Coarctation of the Aorta 

Updated: Nov 20, 2018
Author: Syamasundar Rao Patnana, MD; Chief Editor: Stuart Berger, MD 

Overview

Background

Coarctation of the aorta (CoA) is a relatively common defect that accounts for 5-8% of all congenital heart defects. Coarctation of the aorta may occur as an isolated defect or in association with various other lesions, most commonly bicuspid aortic valve and ventricular septal defect (VSD). The diagnosis of coarctation of the aorta may be missed unless an index of suspicion is maintained, and diagnosis is often delayed until the patient develops congestive heart failure (CHF), which is common in infants, or hypertension, which is common in older children. This article discusses the pathology, pathophysiology, clinical features, noninvasive and invasive evaluation, and therapy in patients with coarctation of the aorta.

Pathologic anatomy

Coarctation of the aorta may be defined as a constricted aortic segment that comprises localized medial thickening, with some infolding of the medial and superimposed neointimal tissue.[1] The localized constriction may form a shelflike structure with an eccentric opening or may be a membranous curtainlike structure with a central or eccentric opening. The coarctation may be discrete, or a long segment of the aorta may be narrowed; the former is more common.

In the past, coarctation of the aorta has been described as preductal (or infantile) type or postductal (or adult) type, depending on whether the coarctation segment is proximal or distal to the ductus arteriosus, respectively. However, a closer examination of the anatomy suggests that all coarctations are juxtaductal.

The classic coarctation of the aorta is located in the thoracic aorta distal to the origin of the left subclavian artery at about the level of the ductal structure. However, rarely, a coarcted segment is present in the lower thoracic or abdominal aorta. In such instances, the coarcted segment may be long and fusiform with irregular lumen; many consider these to be inflammatory or autoimmune in origin, and they may be variants of Takayasu arteritis.

Dilatation of the descending aorta immediately distal to the coarctation segment (poststenotic dilatation) is usually present. A jet lesion on the wall of the aorta distal to the coarctation site may also be present. Varying degrees of hypoplasia of the isthmus of the aorta (the portion of the aorta between the origin of the left subclavian artery and ductus arteriosus) are present in most patients with thoracic coarctation; this hypoplasia may be significant in symptomatic coarctation of the neonate and infant; in children and adults, the isthmus may have only mild narrowing. The transverse aortic arch (the arch between the origin of the right innominate artery and the left subclavian artery) is also hypoplastic in symptomatic neonates and infants. Collateral vessels that connect arteries from the upper part of the body to the vessels below the level of coarctation may be seen; these may be present as early as a few weeks to a few months of life.

The most commonly associated clinically significant defects include patent ductus arteriosus, VSD, and aortic stenosis. The earlier the infant presents, the more likely a significant associated defect is present. Bicuspid aortic valve may be seen in nearly two thirds of infants with coarctation of the aorta, whereas only 30% of those who present in childhood have such an anomaly.

Mitral valve anomalies, although less common than those of the aortic valve, are also associated with coarctation of the aorta. Sometimes, coarctation of the aorta is a complicating feature of a more complex cyanotic heart defect, such as transposition of the great arteries, Taussig-Bing anomaly, double-inlet left ventricle, tricuspid atresia with transposition of the great arteries, and hypoplastic left heart syndrome.

Aortic coarctation is extremely rare in patients with severe right ventricular outflow tract obstructions such as tetralogy of Fallot and pulmonary atresia with intact ventricular septum. Some patients with coarctation of the aorta may have cerebral aneurysms, predisposing them to cerebrovascular accidents with severe hypertension later in life. Coarctation of the aorta is the most common cardiac defect associated with Turner syndrome.

Pathogenesis

The exact mechanism by which aortic coarctation is produced is not clearly understood. The most commonly invoked hypotheses include hemodynamic and ectopic ductal tissue theories. In the hemodynamic theory, an abnormal preductal flow or abnormal angle between the ductus and aorta that increases right-to-left ductal flow and decreases isthmic flow potentiates development of coarctation. Postnatal spontaneous closure of the ductus arteriosus completes the development of aortic obstruction.[2, 3]

A high incidence of coarctation of the aorta in patients with congenital heart defects with decreased antegrade aortic flow in utero and virtual absence of CoA in patients with right heart obstructions lends credence to the hemodynamic theory. Abnormal extension of ductal tissue into the aorta (ectopic ductal tissue).[4, 5] has been postulated to create the coarctation shelf and, with ductal closure, development of aortic obstruction. This theory, however, does not explain the variable degrees of isthmus and aortic arch hypoplasia associated with coarctation of the aorta.

Pathophysiology

Coarctation of the aorta imposes significant afterload on the left ventricle (LV), which results in increased wall stress and compensatory ventricular hypertrophy.

The afterload may be imposed acutely, as occurs following closure of the ductus arteriosus in neonates with severe coarctation. These infants may rapidly develop CHF and shock. Rapid constriction of the ductus arteriosus, producing sudden severe aortic obstruction, seems to be the most likely explanation. As the ductus (aortic end) constricts, the left ventricular afterload rapidly increases, with a resultant increase in left ventricular pressures (systolic and diastolic). This causes elevation of the left atrial pressure, which may open the foramen ovale, causing left-to-right shunt and dilatation of the right atrium and right ventricle. If the foramen ovale does not open, pulmonary venous pressures and pulmonary artery pressures increase, and right ventricular dilatation develops.

Cardiomegaly revealed by chest roentgenography and right ventricular hypertrophy seen on ECG and echocardiography are related to the indirect effects of rapid development of severe aortic obstruction.

LV afterload may also gradually increase, allowing children with less severe coarctation to develop arterial collateral vessels that partially bypass the aortic obstruction. These children may be asymptomatic until hypertension is detected or another complication develops.

The mechanism for development of hypertension is not clearly understood; mechanical obstruction and renin-angiotensin–mediated humoral mechanisms have been postulated.

The mechanical obstruction theory explains the increased blood pressure by postulating that a higher blood pressure is required to maintain flow through the coarcted segment and collateral vessels. The stroke volume, ejected into the limited aortic receptacle, produces a higher pressure proximal to coarctation. However, this theory does not explain the following:

  • The lack of relationship between the degree of elevation of blood pressure and the magnitude of obstruction

  • The increased peripheral vascular resistance distal to the site of obstruction

  • The delayed or lack of reduction of blood pressure immediately following relief of obstruction

The humoral theory postulates activation of the renin-angiotensin system secondary to reduction of renal blood flow and appears to explain most of the clinical features.[6, 7, 8] However, measurement of plasma renin activity in both animal models and human subjects did not show consistently elevated plasma renin levels in the early studies. The reasons for the inability to demonstrate elevation of renin levels may be related to inadequate measurement of salt intake, posture, extracellular fluid volume, and sympathetic influences on renin release. More recent studies demonstrated abnormalities in renin-angiotensin-aldosterone systems.[9] In addition, activation of central sympathetic nervous system may also be responsible for hypertension of aortic coarctation.[10]

Associated anomalies greatly influence pathophysiology.[11] VSD is frequently present, and coarctation exacerbates the associated left-to-right shunt. Other levels of left heart obstruction (aortic stenosis, subaortic stenosis) may be present and may add to LV afterload.

Numerous neurohumoral changes occur with CHF.[12] Sympathetic nervous system activation occurs, resulting in increases in heart rate and blood pressure (BP). The renin-angiotensin system is activated in patients with CHF, particularly in coarctation of the aorta, in which lower-body BP and renal perfusion may be reduced. Activation of the renin-angiotensin system results in vasoconstriction, cell hypertrophy, and the release of aldosterone. The role of the renin-angiotensin system in CHF and the use of drugs to modulate this system are an intense area of research. Unlike most cases of CHF, coarctation of the aorta is more complex because precoarctation and postcoarctation hemodynamics are quite different.

Drugs typically used to treat patients with CHF, such as angiotensin-converting enzyme (ACE) inhibitors and, more recently, angiotensin II antagonists, may have adverse effects in patients with coarctation of the aorta. Attempts to achieve a normal precoarctation BP with these drugs may result in inadequate lower-body perfusion and may precipitate renal failure.

Vasopressin is also increased in heart failure, although its major stimulus for release is angiotensin II. Vasopressin affects free water retention and may result in hyponatremia. The vasoconstrictive properties of vasopressin may further elevate BP in coarctation.

Other substances, such as human brain natriuretic peptide (BNP), an endothelin, may be activated by CHF, although their specific role in coarctation has not been studied.

An additional cause of coarctation of the aorta is trauma that results in aortic dissection. Compromise of the true lumen of the aorta can result in the clinical picture of coarctation with reduced lower-extremity pulses. Urgent intervention is required in this circumstance.

Prognosis

Coarctation of the aorta is a lifelong disease with a guarded prognosis. Relief of obstruction, control of hypertension, follow-up monitoring for recurrent obstruction, and follow-up care of associated anomalies are imperative.

Continue subacute bacterial endocarditis prophylaxis indefinitely, even in the absence of associated abnormalities. Patients without residual obstruction who are normotensive both at rest and with exercise should lead normally active lives without restriction. They should be able to obtain health and life insurance.

Patients with persistent hypertension, untreated residual obstruction, or other complications have a variable prognosis related to the severity of these problems.

Data regarding long-term follow-up are limited. Available studies indicate that significant mortality rates are found at long-term follow-up after surgical correction of aortic coarctation.[16] The survival curve, while not approaching that in the healthy population, is significantly improved compared with Campbell's natural history data.[17] Death appears to be secondary to recoarctation repair, aneurysms at site of coarctation repair or at a remote site, congestive heart failure, bacterial endocarditis, and hypertension. Attempts to define factors that affect long-term survival have been made; age at operation and degree and duration of hypertension prior to surgery appear to affect the long-term survival.

A study by Oliver et al indicated that in young adults who underwent aortic coarctation repair in childhood, the greatest risk factor for heart failure or cardiovascular death is pulmonary hypertension related to restrictive LV physiology. The study involved 159 adults who underwent aortic coarctation repair at mean age 4.1 years. The investigators found that those individuals with a pulmonary artery systolic pressure of over 40 mm Hg were at the greatest risk of death or of being admitted to the hospital for heart failure. Using logistic regression analysis, they also found that pulmonary hypertension in the adults studied was predicted primarily by restrictive LV physiology.[18]

The study did not find heart failure or death to be statistically associated with recoarctation, systemic hypertension, intracardiac lesions, or aortic aneurysm or with treatment with beta blockers or ACE inhibitors/angiotensin receptor blockers.[18]

Morbidity/mortality

Past autopsy studies suggest that the mortality rate in patients in whom coarctation of the aorta is not surgically repaired is 90% by age 50 years, with a mean age of 35 years.[19] In the current era, coarctation of the aorta mortality is often determined by patient age, patient size, and associated major cardiovascular anomalies.

Associated problems that may contribute to death or morbidity include hypertension, intracranial hemorrhage, aortic rupture or dissection, endocarditis, and CHF.

Complications

Coarctation of the aorta is a lifelong disease with complications that may not be evident until many years following an initial and apparently successful repair.

Recurrent coarctation

Recurrence of coarctation is associated with patient size, age at surgery, and associated transverse arch or isthmic hypoplasia. Ductal tissue in the wall of the aorta may involute and contribute to recurrence, as might scarring at the repair site. Some surgeons believe that the use of interrupted sutures in the anterior portion of the anastomotic suture line improves aortic growth and reduces the risk of recurrence. Sometimes, the surgical repair site is unobstructed, yet obstruction develops at the transverse arch or isthmus because of the failure of these areas to grow proportionally to the rest of the arch. Such obstruction may not be detected for many years after initial repair.

Some patients who have undergone initial repair with left subclavian flap aortoplasty may have a tortuosity at the repair site that does not result in obstruction until rapid growth in adolescence.

Aortic aneurysm

Aneurysm of the aorta can occur in unrepaired coarctation of the aorta and has been described in patients with Turner syndrome and coarctation of the aorta. In addition, endocarditis can result in aortic arch aneurysm (mycotic aneurysm), usually distal to the site of obstruction.

Patch repair of coarctation of the aorta results in an increased incidence of aortic aneurysm (usually opposite the site of the patch), particularly if the shelf of coarcted tissue is excised. Patients with aortic aneurysm can be entirely asymptomatic. Hoarseness that results from stretching of the recurrent laryngeal nerve associated with aortic aneurysm has been described. Chest radiographs are unlikely to reveal the aortic aneurysm, but MRI is more useful in delineating the size and extent of aneurysms.

Hypertension

Hypertension may persist, even after successful repair of coarctation of the aorta, and usually relates to the duration and severity of preoperative hypertension. This is probably related to alterations in the renin-angiotensin system and baroreceptors. As with other forms of uncontrolled hypertension, patients may be at risk for premature atherosclerosis, ventricular dysfunction, and rupture of cerebral aneurysms.

Cerebral aneurysms

Berry aneurysms of the circle of Willis or other vessels are believed to occur in as many as 10% of patients with coarctation of the aorta and may be multiple. Aneurysm size tends to increase with age, as does the risk of rupture. Uncontrolled hypertension promotes the growth of the aneurysms and increases risk of rupture. Most patients are asymptomatic until rupture occurs, although some aneurysms may leak prior to rupture, resulting in warning symptoms of headache, photophobia, weakness, or other symptoms. Rupture of a cerebral aneurysm is associated with high mortality rates and should prompt repair of both the aneurysm and coarctation.

Paralysis

Although rare, paraplegia can occur from spinal cord ischemia, resulting from a compromised blood supply to the anterior spinal artery.[20, 21] Risk of paralysis is increased with reduced arterial collateral vessels, prolonged aortic cross-clamping time, and intraoperative sacrifice of intercostal arteries, as well as other factors.

Paralysis is uncommon in the presence of a well-developed arterial collateral supply, emphasizing the importance of assessing collateral arterial flow prior to surgical intervention. Methods to prevent cord ischemia include hypothermia, use of cardiopulmonary bypass, or insertion of a bypass graft (Gott shunt) with partial aortic clamping.

Cardiomyopathy

Cardiomyopathy is usually present in infants with critical coarctation, especially if additional levels of left heart obstruction, such as aortic stenosis or subaortic stenosis, are present. Some patients may have changes of endocardial fibroelastosis that result in chronic dilated cardiomyopathy, requiring medical management or, in rare cases, cardiac transplantation. Hypertrophic cardiomyopathic changes also may occur, predisposing the patient to subendocardial ischemia, arrhythmias, or congestive heart failure (CHF) related to diastolic dysfunction.

Chylothorax

Extensive dissection at surgery may result in disruption of the thoracic duct, leading to chylothorax. Chylothorax is recognized when feedings are instituted postoperatively. Persistent chylous pleural effusions may necessitate long-term chest tube drainage. Some patients respond to dietary therapy with medium-chain triglyceride diet, fat restriction, and/or total parental nutrition. Patients with refractory chylothorax may require pleurodesis or thoracic duct ligation.

Postcoarctectomy syndrome[22, 23, 24]

Restoring pulsatile blood flow to the mesenteric arteries may result in mesenteric arteritis, in which the arteries become distended and may rupture. Reflex arteriolar vasoconstriction occurs as part of autoregulation of blood flow and can result in ischemia.

Clinical manifestations may range from mild abdominal discomfort to an acute abdomen with severe abdominal distention, vomiting, ileus, and progression to intestinal wall hemorrhage or perforation. This syndrome may be related to early return to feeding after coarctation repair. Thus, feedings are usually delayed for 48 hours after surgery, and nasogastric tube decompression is continued until feedings are begun slowly and advanced as tolerated. Patients with severe postcoarctectomy syndrome may require exploratory laparotomy for treatment of bowel necrosis or perforation.

Careful monitoring and good control of BP in the postoperative period may reduce the risk of postcoarctectomy syndrome.

Valvar aortic stenosis, membranous subaortic stenosis, and mitral valve stenosis

These may develop during the follow-up period; if these are significant, transcatheter or surgical relief of the obstruction may become necessary.

Race

No definitive racial differences have been documented in coarctation of the aorta, although some authors have suggested that coarctation of the aorta is less common in Asians.[15]

Sex

The male-to-female ratio is 2:1, although this ratio is not valid in abdominal coarctation of the aorta, in which this rare lesion predominantly affects females. The ratio of abdominal-to-thoracic coarctation is approximately 1:1000. The male preponderance observed in older patients is not seen in infants with coarctation of the aorta.

Age

Generally, patients with coarctation of the aorta present early in life with CHF or later in life with hypertension. Studies continue to document that coarctation of the aorta is often missed in the first year of life,[25, 26] and the median age of referral to a pediatric cardiologist in one study was 5 years. Among 2192 patients reported to the Pediatric Cardiac Care Consortium from 1985-1993, 1337 were infants, 824 were children, and 31 were adults.[27]

Epidemiology

Frequency

United States

Coarctation of the aorta is a common defect and occurs in 6-8% of patients with congenital heart disease.[13, 14] However, coarctation may be found more frequently in infants who present with symptoms prior to age one year.[11]

International

The prevalence of coarctation of the aorta appears to be lower (< 2%) in Asian countries than in European and North American countries.[15]

 

Presentation

History

The presentation of patients with coarctation of the aorta (CoA) varies but may be discussed relative to the patients who present early, often with congestive heart failure (CHF), and the patients who present later, most often with hypertension.

Early presentation

The presence of associated defects and aortic arch anomalies, the extent of patency of the ductus arteriosus, the rapidity of the process of closure of the ductus arteriosus, and the level of pulmonary vascular resistance determine the timing of clinical presentation and the severity of symptoms. Young patients may present in the first few weeks of life with poor feeding, tachypnea, and lethargy and progress to overt CHF and shock.[15, 28] These patients may have appeared well prior to hospital discharge, and deterioration coincides with closure of the patent ductus arteriosus. Presentation may be abrupt and acute with ductal closure.

Development of symptoms is often accelerated by the presence of associated major cardiac anomalies, such as ventricular septal defect (VSD). Symptoms may be subtle at first, and patients may make repeated trips to the physician before finally presenting in extremis.

Late presentation

Patients often present after the neonatal period with hypertension or a murmur. These patients often have not developed overt CHF because of the presence of arterial collateral vessels.

The diagnosis is often made after hypertension is noted as an incidental finding during evaluation of other problems, such as trauma or more routine illness. Other presenting symptoms may include headaches, chest pain, fatigue, or even life-threatening intracranial hemorrhage. True claudication is rare, although an occasional child may experience pain or weakness in the legs.

Many patients are asymptomatic except for the incidentally noted hypertension. Frequently, coarctation of the aorta is not recognized by the primary care physician.[25, 26, 29] Palpation of femoral pulses and measurement of blood pressure during routine examination is necessary to avoid a delay in the diagnosis.

Physical

As with history, physical examination may conveniently separate patients into 2 groups: those who present early with heart failure and those who present later with hypertension.

Early presentation

Neonates may be found to have tachypnea, tachycardia, and increased work of breathing and may even be moribund with shock. Keys to the diagnosis include blood pressure (BP) discrepancies between the upper and lower extremities and reduced or absent lower extremity pulses to palpation. However, when the infant is in severe heart failure, all pulses are diminished. Upon treatment for heart failure, prominent brachial pulses with weak or nonpalpable femoral arterial pulses may be discerned. Diminished pulses on examination should never be disregarded, since the digits appreciate the rate of change in BP, which may be diminished in ductally dependent coarctation, although the measured BP may not show discrepancies. In patients with an aberrant origin of the right subclavian artery from the aorta distal to the obstruction, such discrepancies in BP may not be present, although lower extremity pulses are diminished versus the carotid pulses.

Differential cyanosis (pink upper extremities with cyanotic lower extremities) may occur when right-to-left shunt across a patent ductus arteriosus provides flow to the lower body. Although often not obvious to the eye, differential cyanosis may be documented based on preductal and postductal pulse oximetry measurements and careful inspection. However, in the presence of lesions with large left-to-right shunt (eg, VSD), pulmonary artery saturations may approximate aortic saturations with less obvious differential oximetric findings. Reversed differential cyanosis (upper body cyanosis with normal lower-body oxygen saturation) may occur with transposition of the great arteries, patent ductus arteriosus, and pulmonary hypertension, resulting in right-to-left ductal shunting.

In patients with low cardiac output and ventricular dysfunction, pulses may be diminished diffusely, and BP gradients may seem minimal. Thus, in addition to coarctation, the differential diagnosis of perinatal circulatory insufficiency always includes left ventricular (LV) outflow obstruction, including aortic valve stenosis, subaortic stenosis, and supravalvar aortic stenosis, as well as severe mitral stenosis or insufficiency.

The murmur associated with coarctation of the aorta may be nonspecific yet is usually a systolic murmur in the left infraclavicular area and under the left scapula. Additional murmurs that result from the presence of associated abnormalities, such as VSD or aortic valve stenosis, may also be detected. An ejection click may signify the presence of a bicuspid aortic valve, whereas a gallop rhythm may indicate ventricular dysfunction.

Late presentation

Older infants and children may be referred for evaluation of hypertension or murmur. Hypertension in a fussy infant or a child may be attributed to agitation; thus, comparing BP readings in all the 4 extremities is important. Occasionally, the left arm pressure is lower than the right arm pressure if the origin of the left subclavian artery is involved in the coarctation. Similarly, anomalous origin of the right subclavian artery (below the level of coarctation) may produce decreased or absent right brachial pulse. Careful simultaneous palpation of upper and lower extremity pulses may help confirm suspected coarctation.

In older children, adolescents, and adults, coarctation of the aorta is best diagnosed clinically based on simultaneous palpation of femoral and brachial pulses. Blood pressure in both arms and one leg must be determined; a pressure difference of more than 20 mm Hg in favor of the arms may be considered evidence of coarctation of the aorta.

A murmur in the left infraclavicular area and under the left scapula may be systolic, but the murmur may also sound continuous in the presence of multiple collateral vessels or, occasionally, severe coarctation. An ejection click may be audible when an associated bicuspid aortic valve and a murmur of aortic stenosis or insufficiency are present. Similarly, a murmur of mitral stenosis or LV outflow tract obstruction may also occur. A gallop rhythm may occur in the presence of a hypertrophic noncompliant LV.

Other findings on physical examination may include abnormalities of blood vessels in the retina and a prominent suprasternal notch pulsation. A thrill may be present in the suprasternal notch or on the precordium in the presence of significant aortic valve stenosis. In the rare case of abdominal coarctation, an abdominal bruit may be noted.

Causes

Numerous theories have been proposed for the etiology of coarctation of the aorta, including postnatal ductal constriction,[2, 3] translocation of ductal tissue onto the aorta,[4, 5] and a theory that alterations in intrauterine blood flow cause altered flow through the aortic arch and result in the substrate for coarctation.[2] Coarctation of the aorta manifests when the ductus closes starting at the pulmonary end, with gradual involution of ductal tissue toward the aorta.

Similar to most forms of congenital heart disease (CHD), the etiology of coarctation of the aorta may be explained by multifactorial inheritance hypothesis.[30] The prevalence of coarctation of the aorta in genetic abnormalities such as Turner syndrome (45,X), is as high as 15-20%. Familial patterns of inheritance of coarctation have been reported, as well as for other left heart obstructive lesions. An increase in seasonal occurrence of coarctation of the aorta is reported in September and November.

 

DDx

Diagnostic Considerations

Important considerations

Do not fail to diagnose coarctation of the aorta (CoA). Hypertensive patients may be treated well into adolescence or adulthood without consideration of the diagnosis of coarctation by physicians. When these patients exhibit complications of coarctation, such as a ruptured cerebral aneurysm, significant repercussions may ensue.

Patients may refuse the administration of blood products and yet need repair. This may be particularly true of infants whose parents refuse the use of blood products. In these patients, consider balloon dilation of a native coarctation to achieve temporary or even permanent relief of obstruction.

Physicians may reduce the risk of paralysis by careful attention to documenting the extent of arterial collateral flow prior to surgical repair in patients with native or recurrent coarctation. Multiple precautionary measures, including Gott shunt, may be used if the status of collateral vessels is uncertain.

Cardiac catheterization, if necessary to document the extent of collateral vessels, allows intraoperative measures to protect the spinal cord and to avoid paralysis.

Special concerns

After successful repair of coarctation of the aorta, pregnancy should be well tolerated.[31] Prenatal care should include careful monitoring of blood pressure (BP), since hypervolemia in pregnancy may contribute to worsening hypertension, especially in patients with some degree of residual obstruction or preexisting hypertension. The presence of other associated lesions, such as aortic valve disease, may further complicate obstetrical management. Anecdotal cases document aortic rupture during pregnancy.

Differential Diagnoses

 

Workup

Laboratory Studies

Studies that may be indicated in evaluation of patients with suspected coarctation of the aorta (CoA) are summarized below.

Laboratory studies in neonatal patients who present in shock include the following:

  • Septic workup includes blood, urine, and cerebral spinal fluid (CSF) cultures.

  • Electrolyte levels, BUN, creatinine, and glucose concentrations should be tested.

  • Measure arterial blood gases and serum lactate levels.

Laboratory studies in older patients who present with hypertension include urinalysis, electrolyte levels, BUN, creatinine, and glucose concentrations.

Preductal and postductal pulse oximetry readings may show evidence of ductal right-to-left shunting, especially in the neonate.

Electrocardiography

ECG in the neonate or infant with early onset of coarctation of the aorta may reveal right ventricular rather than left ventricular (LV) hypertrophy. The reasons for right ventricular preponderance in the face of LV outlet obstruction are mentioned in Pathophysiology.

ECG findings in patients with late onset of coarctation of the aorta may be normal or may reveal LV hypertrophy and may show signs of LV ischemia or strain. Sometimes, LV hypertrophy may manifest as increased S waves in leads V5 and V6, the so-called posterobasal LV hypertrophy.

Chest Radiography

Radiography in patients with early onset of coarctation of the aorta may reveal cardiomegaly, pulmonary edema, and other signs of congestive heart failure (CHF).

Radiography in patients with late onset of coarctation of the aorta may reveal cardiomegaly. An inverted "3" sign of the barium-filled esophagus or a "3" sign on a highly penetrated chest radiograph (frontal view) may be visualized. Rib notching secondary to collateral vessels may also be seen.

Echocardiography

Echocardiography delineates intracardiac anatomy and allows assessment of associated significant intracardiac anomalies. The suprasternal notch 2-dimensional echocardiographic view allows evaluation of the aortic arch to assess the transverse aortic arch, isthmus, and severity of coarctation. Doppler echocardiography is used to measure the gradient at the site of coarctation and to identify the pattern of diastolic runoff typically seen in patients with severe obstruction.

Instantaneous peak pressure gradients across the aortic coarctation can be estimated with a modified Bernoulli equation, as follows:

ΔP = 4 (V22 – V12)

ΔP is the peak instantaneous gradient, and V2 and V1 are the peak flow velocities in the descending aortic, distal to coarctation (continuous-wave Doppler) and proximal to the coarctation (pulsed Doppler), respectively. The calculated gradient usually overestimates the measured blood pressure gradient. Presence of pan-diastolic flow indicates significant obstruction. Inclusion of duration-related Doppler flow parameters in the gradient calculation may improve the accuracy of Doppler prediction of coarctation gradient.[32]

When aortic arch cannot be adequately evaluated, abdominal aortic Doppler parameters may help in the diagnosis.[33] Absence of early diastolic reversal along with corrected pulse delay of 2.8 microseconds1/2 or more may best predict significant obstruction.

Magnetic Resonance Imaging and Computed Tomography Scanning

MRI and CT are useful in older or postoperative patients to assess residual arch obstruction, arch hypoplasia, or formation of aneurysms (see image below).[34, 35] Ultrafast CT scanning is preferable if multiple surgical clips or a stent is present in the area of coarctation.

Apart from defining the anatomy, peak systolic pressure gradients may also be calculated using MRI-based computational fluid dynamics.[36]

Aortic coarctation visualized by aortic angiograph Aortic coarctation visualized by aortic angiography.
Aortic coarctation visualized by MR imaging. Aortic coarctation visualized by MR imaging.

Cardiac Catheterization

Cardiac catheterization and selective cineangiography may not be required for diagnosis; however, they allow evaluation of the severity of coarctation, anatomic nature of the aortic obstruction (discrete vs long segment), and arch anatomy, including hypoplasia of the transverse arch or isthmus.

Cardiac catheterization helps to confirm the diagnosis when echocardiography findings are not completely clear, allows the evaluation of intracardiac anatomy and the contribution of associated lesions to the overall hemodynamic disturbance, and is a prerequisite for intervention in the form of either balloon angioplasty or stent implantation in native or recurrent coarctation.

When catheterization is performed, elevations of left ventricular and ascending aortic peak systolic pressures with a peak-to-peak systolic pressure gradient across the coarcted segment are usually found. A peak-to-peak gradient in excess of 20 mm Hg is generally considered indicative of significant obstruction. However, the magnitude of the gradient is not necessarily indicative of the degree of narrowing because the gradient depends on not only the extent of aortic narrowing but also the size and number of collateral vessels. In addition, cardiac output and the state of ductus arteriosus, particularly in the neonate and young infant, also determine the pressure gradient.

Selective aortic root or aortic arch angiography is necessary to clearly demonstrate the aortic narrowing. Aortography is useful in demonstrating the type of aortic coarctation (diffuse, long segment, aortic kinking [pseudocoarctation]); extent of collateral circulation; the size of ductus arteriosus, if patent; and the presence and degree of hypoplasia of transverse aortic arch and aortic isthmus, especially in neonates. If thoracic coarctation is not demonstrated despite clinical features of coarctation or if neurofibromatosis is suspected, abdominal aortography may be needed to demonstrate (or exclude) abdominal coarctation.

LV angiography is particularly useful in neonates and infants who demonstrate ventricular septal defects (VSDs) and in evaluating LV function.

Histologic Findings

Coarctation of the aorta results from marked ridgelike thickening of the media of the aortic wall opposite the insertion of the patent ductus arteriosus or ligamentum arteriosum.

The intima in this area may be thin initially but may thicken over time.

This ridge or shelf becomes an obstruction when the patent ductus involutes and when ductal tissue in the wall of the aorta involutes.

 

Treatment

Medical Care

Early presentation of coarctation of the aorta (CoA)

Note the following:

  • Treatment in patients with congestive heart failure (CHF) includes the use of diuretics and inotropic drugs.

  • Prostaglandin E1 (0.05-0.15 mcg/kg/min) is infused intravenously to open the ductus arteriosus.

  • Ventilatory assistance is provided to patients with markedly increased work of breathing.

  • Infusion of inotropic drugs (dopamine, dobutamine, epinephrine) is useful when ventricular dysfunction is present, especially with hypotension.

  • A Foley catheter is inserted to monitor renal perfusion and urine output.

  • ABGs are tested to monitor acidosis.

  • An umbilical artery catheter may be placed in neonates to assess the response to prostaglandin infusion with regard to improving lower-body blood flow.

  • Patients stabilized by the above interventions are better candidates for surgical or catheter intervention.

  • In the presence of associated defects, the significance of coarctation on the clinical course of the patient should be assessed with echo-Doppler and/or catheterization and angiographic studies. If the coarctation has a significantly adverse effect on the physiology of the associated defects, and consequently the clinical status, the coarctation should be initially relieved with surgery or balloon angioplasty and the patient reassessed with regard to need for intervention for the associated defects. Based on the authors' experience and that of others, the aortic obstruction is usually a major contributing factor for the symptomatology, and relief of the obstruction may postpone or avert the need for additional surgical intervention for the associated cardiac defects.[37, 38]

Late presentation of coarctation of the aorta

Treatment of hypertension

Preoperative hypertension can be effectively treated using beta-blockers. The goal should be to reduce upper extremity hypertension, but remember that vigorous attempts to achieve normal upper extremity blood pressure (BP) may result in inadequate lower-body perfusion. Beta-blocker therapy prior to surgery may reduce the severity of postoperative hypertension, although most patients with preoperative hypertension require at least transient postoperative therapy. Remember that relieving the aortic obstruction promptly rather that attempting to treat hypertension with antihypertensive medications is better.[1]

Postoperative hypertension can be treated short-term with vasodilators, such as sodium nitroprusside, and intravenous beta-blockers, such as esmolol. When longer-term antihypertensive therapy is required, beta-blockers may be continued, and if no residual arch obstruction exists, ACE inhibitors or angiotensin II antagonists (pediatric dosing not established for angiotensin II antagonists) may be added if hypertension persists despite beta-blocker therapy.

Guidelines regarding beta-adrenergic receptor blockers have been established.[39]

One study concluded that data is not sufficient to discourage or recommend the use of beta-blockers in children with CHF.[40]

Evaluate associated abnormalities

Associated abnormalities include aortic stenosis, subaortic stenosis, and mitral valve disease.

Evaluate adequacy of collateral blood vessels

The adequacy of the collateral blood vessels is used to assess the safety of surgical intervention.

Surgical Care

Significant hypertension or congestive heart failure (CHF) is an indication for intervention. Surgical relief of the aortic obstruction and catheter interventional techniques (balloon angioplasty and stents) are available alternatives. Symptomatic neonates and infants should undergo urgent intervention soon after the infant is stabilized. Asymptomatic infants, children, adolescents, and adults should undergo the procedure electively. If neither hypertension nor heart failure is present, elective surgical or balloon therapy in children aged 2-5 years is suggested. Waiting beyond age 5 years for surgery or balloon therapy to relieve aortic obstruction is not advisable because of the evidence of residual hypertension if intervention is performed after age 5 years.[41]

Since the introduction of surgical correction by Crafoord and Nylin (1945) and by Gross and Hufnagel (1945) in the early 1940s, surgical therapy has been the preferred treatment for aortic coarctation. Various surgical techniques have been used to treat patients with coarctation of the aorta, namely, resection and end-to-end anastomosis, patch aortoplasty, left subclavian flap aortoplasty, and tubular bypass grafts. The techniques are occasionally combined or modified to fit the individual patient's anatomy.[42]

For instance, a reverse left subclavian flap aortoplasty may be used, turning the left subclavian artery as a patch back toward the left carotid artery to enlarge an area of transverse arch hypoplasia. In addition, an extended end-to-end repair may be used, in which the segment of descending aorta is beveled and brought up to the underside of the transverse arch to enlarge areas of transverse arch hypoplasia. The exact technique used varies depending on the patient's age at presentation, size, associated abnormalities, and arch anatomy. A surgical approach from a median sternotomy, rather than the classic left lateral thoracotomy, is used commonly in complex arch repairs.

In a review of 1337 patients undergoing repair of coarctation in infancy, the following findings were reported[27] :

  • Subclavian flap aortoplasty was performed in 763 patients (57%). Resection in end-to-end anastomosis was used in 406 patients (30%), and patch aortoplasty was used in 133 patients (9.9%). In addition, 20 patients underwent placement of an interposition graft or bypass graft.

  • In the series, the mortality risk was highest in neonates in whom surgery was performed during the first week of life, whereas only 8 of 279 infants aged 3 months to 1 year who underwent surgery died. Mortality associated with surgery was also higher in smaller infants, particularly in infants who weighed less than 3 kg and infants with associated cardiac anomalies.

  • The presence of a ventricular septal defect (VSD) with or without minor associated anomalies increased the risk of death from 0.9% (no anomalies) to 6.8% (with VSD). Complex associated anomalies, such as a single ventricle or transposition of the great arteries, greatly increased the mortality rate to 16.6%. Similarly, the surgical mortality rate in neonates who required surgery early was high at 45%. Urgent surgery may be required if the patent ductus arteriosus cannot be opened and the patient continues to have poor urine output and acidosis.

In the presence of a hemodynamically significant VSD, historically, placement of a pulmonary artery band was performed to limit pulmonary blood flow at the time of left thoracotomy for coarctation repair. Current surgical approach uses a single-stage repair of the coarctation and VSD, usually through a sternotomy, even in the small neonate.

In severe transverse arch hypoplasia that results in significant residual obstruction following coarctation repair, an ascending-to-descending aortic conduit may be placed. This is usually a less favorable approach because the patient may be obligated to undergo subsequent surgeries for conduit replacement.

In most centers, associated defects may be addressed at the time of surgery for coarctation by proceeding with a median sternotomy to repair lesions such as mitral stenosis or subaortic obstruction or to accomplish left ventricular (LV) outflow tract enlargement. Occasionally, the adequacy of the LV volume is called into question, and the patient may require a modified Norwood repair. Decision making about this issue is addressed in Hypoplastic Left Heart Syndrome. However, note that hypoplasia of the left heart structures, particularly the LV, associated with isolated CoA usually improves following relief of aortic obstruction.[43]

Repair of coarctation in the asymptomatic child or adolescent is usually undertaken on an elective basis after assessment of associated anomalies and appropriate preoperative evaluation. The timing of intervention in the otherwise asymptomatic patient has been debated. The rationale for delaying surgery until age 3-5 years has been based on the size of the aorta in childhood relative to the anticipated adult size. Because significant obstruction occurs when the diameter of the aorta is reduced by 50% or more, delaying surgery until age 3-5 years allows the aorta to be larger than half the anticipated adult size at operation, theoretically reducing the risk of significant residual obstruction in the event that the surgical repair site does not grow over time. However, issues of hypertension, progressive LV hypertrophy, or LV dysfunction mandate earlier repair.

Improvements in surgical techniques have led most cardiologists to recommend surgery at the time of diagnosis, especially in patients with hypertension. In patients with only mild obstruction, especially those diagnosed in the first year of life, surgery may safely be delayed and the patient monitored for worsening obstruction or development of hypertension prior to recommending surgery.

Pseudo-coarctation of the aorta refers to abnormal tortuosity of the aorta that does not result in significant obstruction or hypertension and is noted for the lack of development of collateral vessels. This abnormality does not require surgical intervention.

Surgical repair of coarctation of the aorta is accomplished in children and adolescents with generally good results and low mortality. Of 824 patients who underwent coarctation repair in childhood, 431 (52%) underwent end-to-end anastomosis, whereas patch aortoplasty was performed in 214 patients (26%) and only 109 patients (13%) underwent subclavian flap aortoplasty. Death occurred in only 6 of 824 patients for a total mortality rate of 0.73%.[27] The surgical era of this cohort does not reflect the current surgical strategy for aggressive complete arch repair or the aorta and all associated lesions. The trend is toward the less frequent use of patch aortoplasty because of concerns regarding the development of aortic aneurysm at the site of repair.[44, 45, 46, 47]

Operative mortality rates in neonates and infants are high (4-50%), whereas the operative mortality rates in older children are low (0-5%). The high mortality in the young infant appears to be related to the condition of the infant at the time of surgery and the associated defects.

Significant recoarctation (6-33% in infants, 0-18% in older children)[37, 48] ; formation of aneurysms in all types of coarctation repair,[44] particularly well-documented following prosthetic patch angioplasty[48, 49] ; development of paraplegia[20, 21, 50] ; paradoxical hypertension[22, 23, 24] ; and vascular complications related to subclavian flap repair[51, 52, 53, 54, 55] continue to be problems.

In a study examining long-term results of surgery by MRI of 247 patients aged 33.0 ± 12.8 years, restenosis (mild in 31% and significant in 9%) and dilatation of the aortic segment (13%), with discrete aneurysm at the repair site in 9%, was observed. However, antihypertensive therapy was required, which controlled the blood pressure in 93% patients.[56] Mortality rate was low, but significantly higher than age-matched healthy controls.

Late hypertension continues to be a problem.[57]

Despite these problems, surgical repair is considered by many to be the therapeutic option of choice in the treatment of aortic coarctation. Some groups of workers, including the authors' group, consider balloon angioplasty the initial therapy of choice and reserve surgical intervention for the following coarctations:

  • Coarctations that involve the long segment of the aorta

  • Coarctations that are completely or almost completely occluded so that no catheter or guide wire can be passed across the coarcted segment

  • Coarctations that are associated with a large patent ductus arteriosus and ventricular septal defect that requires prompt surgical intervention for the primary cardiac problem.

Balloon angioplasty

Gruntzig's technique of balloon angioplasty was adopted by Sos et al (1979), Singer et al (1982), and Sperling et al (1983) for enlargement of coarcted aortic segments in a postmortem specimen, postsurgical recoarctation, and native coarctation, respectively. Other cardiologists then used this technique to treat native coarctation of the aorta. Numerous investigators reported their experiences with balloon angioplasty of native aortic coarctations. However, the use of balloon angioplasty for treatment of native aortic coarctation is controversial.[1, 58] This section describes the technique and the results of balloon angioplasty.

Technique[15, 48, 59]

Cardiac catheterization and selective cineangiography are performed to confirm the clinical diagnosis, to exclude other cardiac defects, and to assess suitability for balloon angioplasty. Once balloon angioplasty is chosen, a 4F-6F multi-A2 (Cordis) catheter is introduced into the femoral artery percutaneously and is positioned across the aortic coarctation. Then, a 0.021-0.035 in J-tipped guide wire is passed through the catheter into the ascending aorta and the tip of the wire positioned in the ascending aorta. A 4F-7F balloon angioplasty catheter is then positioned across the aortic coarctation. The balloon is inflated with diluted contrast material to approximately 3-5 atm of pressure or higher, depending on the manufacture's recommendations.

Monitoring pressure of inflation via any of the commercially available pressure gauges is recommended. The balloon is inflated for 5 seconds. A total of 2-4 balloon inflations are performed 5 minutes apart. Aortography and measurement of pressure gradients across the coarctation of the aorta are performed. The heart rate, systemic pressure, and cardiac index are recorded prior to and 15 minutes after balloon dilatation to ensure that the change in pressure gradient is related to balloon dilation rather than changes in patient status.

The author generally performs this procedure with the patient under conscious sedation, whereas others advocate general anesthesia. Most cardiologists use percutaneous femoral artery approach for cardiac catheterization and balloon angioplasty. Occasionally, femoral artery cutdown or left axillary artery cutdown is necessary if the percutaneous approach is unsuccessful. The authors and others have used a transumbilical approach in neonates in an attempt to avoid the use of the femoral arteries.[15, 60] In patients in whom the aorta can be entered from the right ventricle (either directly in patients with transposition of the great arteries or double outlet right ventricle or indirectly through a ventricular septal defect), balloon angioplasty may be performed transvenously.

The size of the balloon chosen for angioplasty is 2 or more times the size of the coarcted segment, but no larger than the size of the descending aorta at the level of the diaphragm, as measured from a frozen video recording. The authors usually choose a balloon that is midway between the size of the aortic isthmus (or transverse aortic arch) and the size of the descending aorta at the level of diaphragm. If the relief of obstruction is not adequate (pressure gradient reduction to < 20 mm Hg and angiographic improvement), a balloon as large as the diameter of the descending aortic at the level of diaphragm is chosen for additional dilatation.[48, 61]

The authors usually give 100 U of heparin per kilogram prior to introducing the balloon-angioplasty catheter. Activated clotting times should be measured every 30 minutes and maintained between 200 and 250 seconds. The heparin effect is neither reversed nor continued after the procedure. Administering adequate doses of heparin to prevent thromboembolism is important.[48, 62]

The balloon inflation pressure should be monitored and attempts should be made not to exceed that stated by the manufacturer; this is to prevent balloon rupture and its adverse effects.[37, 48]

A catheter or a guide wire must not be manipulated over the site of a freshly dilated coarctation of the aorta. A guide wire should always be left in place across the coarctation segment, and all angiographic and balloon-dilatation catheters should be exchanged over the guide wire.

Balloon size should be carefully chosen to prevent aneurysm.

Use of large-caliber angioplasty catheters may result in significant femoral artery compromise. Availability of balloon catheters that can be introduced through 4F sheaths appears to reduce the femoral artery injury. Even these may injure the femoral artery in the young infant; in such situations, the authors use 3F sheaths through which the more recently available balloon dilatation catheters (eg, Mini-Tyshak [Braun] catheters) can be introduced, which may further reduce such complications.

Short-term results

Despite an initial report of poor results,[63] subsequent experience with balloon angioplasty appears encouraging and has been detailed elsewhere.[32, 37, 48, 64, 65, 66] A reduction of pressure gradient across the coarctation and an increase in the size of the coarcted segment have been observed. The collateral vessels promptly diminish. The femoral pulses, which had been either absent or markedly reduced and delayed (when compared with brachial pulses) become palpable with increased pulse volume after balloon angioplasty.

The infants who were in heart failure improved, as did their hypertension. The infants who were ventilator dependent could be weaned off of the ventilator support and were extubated. Most infants (beyond the neonate period) and children are discharged from the hospital within 24 hours after balloon angioplasty. None of the authors' patients required immediate surgical intervention.

Intermediate-term follow-up results

Several investigators have reported 1-year to 2-year follow-up results, and these studies suggest continued improvement. From the authors' study, 60 patients (58 catheterization, 2 clinical) were observed; the residual gradients 14 ± 11 (mean ± standard deviation [SD]) months following angioplasty remained low at 16 ± 15 mm Hg.[67] These gradients continue to be lower (P< .001) than those prior to angioplasty (46 ± 17 mm Hg) and are slightly higher (P< .05) than the gradients (11 ± 9 mm Hg) immediately following angioplasty. The angiographically measured coarctation segment remained wide. Only a modest increase is found (11 ± 9 vs 16 ± 15 mm Hg; P< .05) in peak gradients for the group as a whole, but, when individual patient values are examined, 15 (25%) of the 60 patients had evidence of recoarctation, defined as a peak-to-peak systolic pressure gradient in excess of 20 mm Hg.

The incidence of recoarctation is higher in neonates (5 [83%] of 6; P< .01) and infants (7 [39%] of 18; P =.011) than in children (3 [8%] of 36). Ten of these children underwent repeat balloon angioplasty, and their gradients were reduced (P< .001) from 39 ± 11 mm Hg to 10 ± 6 mm Hg.[67] Early in the authors' experience, 2 patients underwent surgical resection with good results. The final 3 children had no discrete narrowing and had no hypertension; therefore, no intervention was recommended. Aneurysms developed in 3 (5%) of 58 patients who underwent follow-up angiography; one of these patients required surgical excision of the aneurysm and the other 2 are observed clinically.

Similar high recoarctation rates were documented by our group[68, 69] in neonates and infants less than three months of age, but balloon angioplasty provided successful and effective palliation in 92% infants.

Long-term follow-up results

Only scant data can be found on long-term follow-up after balloon angioplasty of native coarctation. Despite recoarctation and aneurysms, some requiring repeat intervention at intermediate-term follow-up, the long-term follow-up results (5-9 y) appear encouraging, in that minimal incidence of late recoarctation and no late aneurysm formation was found.[58, 70, 71]

Event-free survival curves following initial balloon angioplasty suggest that the event-free rates are better (P< .001) in children than in infants and neonates. In most children, the arm blood pressure remained normal and the blood pressure–determined gradient between arms and legs remained low.[67]

Applicability in adult patients

Although balloon angioplasty of aortic coarctation has most frequently been used in neonates, infants, and children, it can also be used in adult patients.

Lababidi et al (1984) were the first to apply this technique in a 27-year-old man, resulting in reduction of peak systolic pressure gradient across the coarctation (from 70 to 15 mm Hg), angiographic improvement, and reduced hypertension (190/124 mm Hg vs 130/80 mm Hg). They subsequently reported their experience with balloon dilatation of native coarctation in 8 consecutive adults, aged 19-30 years (25 ± 5 y).[72] The systolic pressure gradient across the coarctation was reduced from 48 ± 19 mm Hg to 7 ± 5 mm Hg. The size of the coarcted segment increased from 6.8 ± 2.2 mm to 15.2 ± 5 mm. No complications were encountered. Clinical and echo-Doppler follow-up one year after the procedure revealed good results, with no more than 15 mm Hg peak systolic blood pressure difference between the arms and the legs (measured by cuff). They concluded that results in young adults are similar to those observed inchildren,balloonangioplastyshouldbeconsideredasanoptiontosurgicalintervention, and follow-up studies (>1 y) are required.

Other reports followed, which revealed equally good results.[73] Based on a review of these studies, aortic perforation during the procedure and aneurysmal formation at follow-up are also apparent in adults. In addition, intimal dissection that persisted at 6-month follow-up was seen in one patient. Therefore, (1) avoiding manipulation to the tips of the catheters and guide wires in the region of freshly dilated coarctation, (2) choosing an appropriate-sized balloon (no larger that the diameter of the descending aorta at the level of the diaphragm), and (3) monitoring for the development of aneurysms and, if found, closely following the progression of aneurysms with repeated angiography or MRI are prudent guidelines. Twenty-year follow-up for discrete coarctations appear encouraging.[74]

Surgery compared with balloon therapy

Scant data are available to compare surgical intervention with balloon angioplasty. In an attempt to compare the safety and efficacy of balloon angioplasty with surgical correction of aortic coarctation, the authors scrutinized 49 papers (published from 1980-1991) that reported on results of surgery in infants younger than 1 year and 9 papers that compared the results of balloon angioplasty in children.[37, 48] These data showed that recoarctation rates are similar, whereas the mortality rates are slightly higher in the surgical than the balloon angioplasty series. Similar comparison of results in children older than 1 year showed identical results.

Shaddy and associates (1993) prospectively randomized 36 patients aged 3-10 years to undergo either balloon angioplasty (20 patients) or surgery (16 patients) and found similar immediate pressure gradient relief in both groups.[75] The risks of aneurysm formation and restenosis were higher in the balloon angioplasty group, whereas risks of neurologic complications were higher in the surgical group. They concluded that balloon angioplasty in coarctation of the aorta may provide an effective initial alternative to surgery in children beyond infancy and suggested that further follow-up is needed to evaluate the long-term risks of aneurysms following angioplasty.

The senior author compared the efficacy and safety of balloon angioplasty with those of surgical correction in infants younger than 3 months.[38] Data on 29 infants who underwent intervention for aortic coarctation from 1982-1992 were examined. Fourteen infants underwent surgical repair, and 15 underwent balloon angioplasty. The data indicated that the degree of relief of aortic obstruction and the frequency with which reintervention is needed are similar in both groups. However, balloon angioplasty carries lower morbidity rates and complications than with surgical therapy. Based on these data, the we suggested that balloon angioplasty may be an acceptable alternative to surgery in the treatment of symptomatic aortic coarctation in infants younger than 3 months.

Shim and colleagues (1997) compared hospital charges and found lower charges for patients who underwent balloon therapy compared to surgery.[76]

Complications such as paraplegia[20, 21, 50] and paradoxical hypertension[22, 23] are seen following surgical repair, although such complications are rare and, if present, very mild and inconsequential following balloon angioplasty. Aneurysms following balloon angioplasty[48, 77, 78] are of concern and need further study, although such aneurysms are also seen with surgical repair.[44] The femoral artery occlusion rate following balloon angioplasty may be higher than that seen with surgical therapy. However, vascular complications can occur in the left upper limb following coarctation repair with subclavian flap aortoplasty; these complications include gangrene, reduction in the length and muscle mass of upper arm and forearm, and abnormal Doppler blood flow velocities in brachial arteries, suggesting potential for symptoms of ischemia.[51, 52, 53, 54]

Cowley et al (2005) compared long-term (mean, 10-11 y) results of balloon angioplasty with those of surgery for patients with native aortic coarctation who were randomized at entry into the study and found similar resting blood pressures, residual gradients across the coarctation, exercise performance, aortic arch anatomy based on MRI angiography, and reintervention rates.[79] However, the incidence of aneurysms and greater arm-to-leg blood pressure difference during exercise was higher in the balloon group than in the surgery group.

Cowley et al suggested that surgery is preferable to balloon angioplasty in the management of aortic coarctation in children. Although randomization is a virtue of the study, the study involves only 36 children, with only 21 (58%) returning for reevaluation. Furthermore, other studies in which a larger number of balloon angioplasty procedures were evaluated at long-term follow-up revealed 5% aneurysm formation. Aneurysm formation was also detected in surgical patients. Consequently, a multi-institutional randomized study with a larger number of subjects is in order to resolve the issues brought out by this paper.[73]

Rodés-Cabau et al (2007) compared transcatheter and surgical treatment and concluded that immediate results were similar, but with reduced morbidity and duration of hospitalization with transcatheter intervention.[80] However, angioplasty was associated with a higher rate of reintervention and aneurysm formation.

Wong and associates (2008) used decision analysis to compare preferences for balloon angioplasty versus surgery and concluded that balloon angioplasty is preferred over surgery as the initial treatment for native aortic coarctation in children; however, this type of decision analysis approach was questioned.[81]

Based on the above review, the effectiveness of balloon angioplasty appears to be comparable with that of surgery; the mortality rates are similar (and are probably related to the associated cardiac defects, not related to type of intervention performed), and morbidity and complication rates are lower with balloon angioplasty than with surgical therapy. Balloon angioplasty may be an effective alternative to surgery for the relief of aortic coarctation.

Recoarctation

Residual and recurrent obstructions cannot be easily distinguished, and the term recoarctation may be used to describe both entities. Recoarctation is defined as a peak-to-peak systole pressure gradient in excess of 20 mm Hg with or without angiographically demonstrable narrowing.[82] Recoarctation following both surgical correction and balloon angioplasty has been described.

Recoarctation following surgery does not depend on the type of surgical repair[44, 48] ; it has been observed following resection with end-to-end anastomosis, subclavian flap angioplasty, prosthetic patch repair, subclavian artery turn-down procedure, and interposition tube grafts. The reported incidence of recoarctation has varied depending on the study. The average recoarctations rates were 11-17% in neonates and infants younger than 1 year and 5.6% in children older than 1 year. In a large cohort of patients studied by Pinzon et al (1991), recoarctation occurred in 23%.[44] Recent reports demonstrate similar recoarctation rates.[83, 84] The younger the child at surgery, the higher the chance for recoarctation.

Although no consensus has been reached in regard to the method of intervention (surgery vs balloon angioplasty) for native aortic coarctation, both cardiologists and cardiovascular surgeons generally agree that balloon angioplasty is the treatment of choice for postsurgical aortic coarctations.[48, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94] The immediate and follow-up results of balloon angioplasty for postsurgical recoarctation are essentially similar to those of native coarctations and have been reviewed in detail elsewhere.[71]

Restenosis following balloon angioplasty also appears to be age dependent; the younger the child, the greater the chance for recoarctation.[58] The authors[58, 64] and others[70] recommend repeat balloon dilatations in such cases, whereas others[95] prefer surgical intervention.

The technique of balloon angioplasty for the management of both postsurgical and post–balloon angioplasty recoarctations is similar to that described above for native coarctation.[64]

Conclusions

Based on an extensive review of the literature and personal experience with the procedure for more than 25 years, some generalizations with regard to balloon therapy may be made, as follows.

Children older than 1 year and adults with discrete native coarctation are candidates for balloon dilatation. Most cardiologists agree on this issue. Long-segment coarctations or those associated with significant isthmic hypoplasia may be candidates for stent placement, especially in adolescents and adults.

Recurrent coarctation following previous balloon angioplasty may be treated with repeat balloon angioplasty; others prefer surgery. If the recoarcted segment is long, surgical treatment in younger children and stents in adolescents and adults seem appropriate.

Treatment of coarctation in neonates and infants is perhaps the most controversial issue. Many cardiologists prefer surgical intervention, whereas a few cardiologists may opt for balloon angioplasty.

Balloon angioplasty is useful in the treatment of extremely ill neonates and infants with severe coarctation; in this subset of patients, the balloon angioplasty has a significant advantage over a surgical approach.

Most cardiologists and surgeons agree that balloon angioplasty is the treatment of choice for postsurgical recoarctations.

Aortic stents

Vascular stenotic lesions can be opened with balloon angioplasty, but, because of the elastic recoil of the vessel wall, the vessel lumen may return to the predilation size following withdrawal of the balloon catheter. Such recoil and vascular dissection following balloon dilatation can be circumvented with implantation of endovascular stents. Dotter (1969), in the late 1960s, suggested this concept and implanted spiral coil-spring prostheses into the experimentally produced peripheral artery stenotic lesions. The stent concept and technology were dormant until the early 1980s, when the balloon-expandable and self-expanding stents were designed and used.[96] Initially, stents were used in the treatment of peripheral arterial disease and coronary artery stenotic lesions in adults. The technique was then extended to the treatment of other stenotic vessels, including aortic coarctation.[61, 97]

Despite reasonably good short-term and long-term results of balloon angioplasty, some problems remain, including restenosis, probability of aortic rupture, formation of aneurysms, and inability to effectively treat long-segment tubular narrowing. Because of these and other reasons, endovascular stenting of aortic coarctation has gained acceptance over the last decade.[60, 91, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119]

The following are perceived advantages of stents over balloon angioplasty:

  • The ability to expand tubular long-segment coarctation, hypoplastic isthmus, and the distal transverse aortic arch

  • The ability to increase the coarcted segment diameter independently of the intimal tear

  • The ability to decrease the probability of restenosis

  • The ability to prevent dissection of the torn intimal flap by facilitating apposition of the intima against the media

  • The ability to prevent aneurysms because of the support of the weakened aortic wall with the stent and neointima

O'Laughlin et al (1991) were the first to use a stent for the treatment of aortic coarctation, although the results in a 12-year-old child were marginal. Subsequently, numerous others reported the use of a stent in aortic coarctation with encouraging results.[61, 64, 91, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 117, 118, 119]

Because of growth issues and the need for large sheaths for implantation, most cardiologists limit stent usage to adolescents and adults. The following are indications for using stent:

  • Long-segment coarctation

  • Associated hypoplasia of the isthmus or aortic arch

  • Tortuous coarctation with malalignment of the proximal and distal aortic segment

  • Recurrent aortic coarctation or an aneurysm following prior surgical or balloon therapy

Technique

The procedure may be performed under conscious sedation or under general anesthesia. Cardiac catheterization is performed to confirm the clinical and echocardiographic diagnosis and to exclude other cardiac defects. Pressure gradients across the coarctation and selective cineangiography in multiple angiographic projections are initially performed to demonstrate the stenotic lesions.[60]

The following measurements are made: (1) the diameter of the stenotic lesion, (2) the diameter of the aorta proximal and distal to the obstructive segment, and (3) the length of the vessel that can be stented. All the measurements are made in 2 orthogonal views and averaged. Foreshortening of the vessel length is taken into account based on the anatomy. These measurements are used in the selection of expanded diameter and length of the stent. Heparin (100 U/kg) is administered, and activated clotting times are monitored and maintained between 200-250 seconds by giving additional doses of heparin, as needed.

An end-hole catheter (5F-6F multi-A2) is positioned across the coarctation with the help of a soft-tipped 0.035-in Bentson guide wire. The guide wire and catheter are advanced into the ascending aorta. The tip of the catheter may also be placed in the right or left subclavian arteries, depending on the location and angulation of the coarcted segment. The catheter is left in place, and the guide wire is removed and replaced with either an extra-stiff exchange-length 0.035-in Amplatz or a super-stiff, short tip, Amplatz guide wire. The catheter is then removed.

If the approach to the lesion is tortuous or difficult to reach, the authors select a 0.038-in super-stiff Amplatz wire. An appropriate-sized long blue Cook sheath with a multipurpose curve and a radiopaque marker at the tip is introduced over the stiff wire. Once the tip of the sheath is past the site intended to be stented, the dilator is removed and the sheath flushed. Sometimes, the dilator has to be withdrawn slightly to position the tip of the sheath at the desired location.

The selection of the sheath diameter obviously depends on the size of the stent delivery catheter. The authors have always attempted to select a balloon delivery system that would allow the smallest possible sheath diameter. Initially, when other workers were using Meditech PE-MT balloon catheters, which required 11F sheaths, the authors were using Olbert balloon catheters, which can be introduced through 8F or 9F sheaths for mounting the stent. Subsequently, the authors have used Bridge stents, which can also be delivered via 8F or 9F sheaths.[60] Most recently, the authors used IntraStent DoubleStrut stents and Palmaz Genesis.[116] The latter stents are mounted on balloon-in-balloon (BIB) catheters. The size of the sheath used is 1F larger than the sheath size needed for the BIB catheter.

The selected stent is hand crimped onto a BIB catheter; the authors use a sterile umbilical tape to further crimp the stent onto the balloon.

The balloon catheter, with the stent mounted on it, is advanced over the stiff guide wire but within the sheath and positioned across the coarctation segment. The tip of the sheath is withdrawn distal to the aortic coarctation based on bony landmarks. Contrast is also injected via the side arm of the blue Cook sheath, and the position of the stent is adjusted as necessary. Some cardiologists place catheters into the ascending aorta via trans-septal route or from radial artery for angiography during stent placement.[120] Although this may provide better visualization, the authors do not routinely recommend it to avoid additional time in the catheterization laboratory and morbidity associated with such additional procedures.

In cases in which the BIB catheter is used, the inner balloon is inflated at the manufacturer's recommended pressure and the position of the stent adjusted, if needed, followed by inflation of the outer balloon, thus implanting the stent. The balloon catheter is then advanced slightly, centering the balloon across the proximal end of the stent, and the outer balloon is re-inflated to ensure apposition of the stent against the vessel walls. The balloon catheter is then centered over the distal end of the stent. This is performed by advancing the tip of the sheath over the deflated balloon into the stent to prevent inadvertent displacement of the stent.[121] The outer balloon is then re-inflated to ensure apposition of the distal stent against the vessel walls.

If the outer balloon diameter is not as large as the desired diameter of the stent, additional balloon expansion with larger diameter balloons is performed. The author always tries to avoid this step by using an outer balloon of the BIB catheter at the desired diameter. Following the removal of the balloon catheter, a multitrack catheter[122] is positioned over the wire, and pressure pullback tracings and angiography are performed to assess the results of stent implantation.

The effect of heparin is not reversed, and no additional doses of heparin are administered. Intravenous cefazolin 25 mg/kg/dose (maximum of 1 g) is started in the catheterization laboratory, and 2 additional doses are administered at 6- to 8-hour intervals. Aspirin in platelet-inhibiting doses (5-10 mg/kg/d) is started on the day following the procedure and continued for 6 weeks. Use of heparin overnight on the day of procedure and more potent platelet-inhibiting drugs or anticoagulation with warfarin (Coumadin) have been undertaken in the past. At present, the data do not indicate the need for intensive anticoagulation. Aspirin alone appears to suffice. However, more potent platelet-inhibiting drugs, such as clopidogrel, may be used in adults.

To avoid potential balloon rupture, the tip of the guide wire is placed in the right subclavian artery instead of the ascending aorta, which is the usual practice for balloon angioplasty. Try not to position the stent across the origins of left common carotid artery and left subclavian artery. However, on occasion, avoiding the subclavian artery is impossible. In such situations, the authors have carefully traversed the stent cells (in between the struts) with a soft guide wire followed by a multi-A2 catheter. The stent cell is then dilated with an angioplasty balloon of a diameter equal to that of the proximal left subclavian artery; uncompromised flow to the left subclavian artery was found in these patients. Predilation of the coarcted segment with balloon angioplasty prior to stenting is no longer recommended.

Immediate results

The reduction of peak systolic pressure gradients and an increase in the diameter of the coarcted segment have been demonstrated following stent implantation.[60, 73, 88, 99, 100, 101, 102, 103, 104, 105, 106, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 123] Stenting was found to be effective in postsurgical and postballoon recoarctations, as well as in native coarctations. The ratio of diameters of coarcted segment to the descending aorta at the level of the diaphragm increased to unity in many patients who undergo aortic stenting. Improvement in the size of hypoplastic isthmus or transverse aortic arch and exclusion of the aneurysm, if present, also occurred after stent placement.

In the first series of 10 patients published by Suarez de Lezo et al in 1995,[100] the peak systolic pressure gradient across the coarctation decreased from 43 ± 12 to 2 ± 3 mm Hg (P< .001). The ratio of isthmus/descending aorta increased from 0.65 ± 0.14 to 1 ± 0.08 following the procedure. Similar results have been reported subsequently by other investigators.[68, 73]

Complications

Vessel disruption,[100] displacement of stent,[100, 106, 108, 113, 124] stent fracture,[125] and aneurysms[104, 106] are rare but do occur. Balloon rupture that results in inadequate stent expansion and stent migration has been reported but may be prevented by avoiding curvature of the balloon or stent assembly, the use of newer stents with less injurious ends, and the use of BIB catheters.[99, 113]

Because of the large size of the sheath required, loss of pulse and bleeding from a puncture site may occur. Use of vascular closure devices may help circumvent this problem. Rare complications included myocardial infarction and retroperitoneal hemorrhage.

Follow-up results

Most studies had only a short-term and incomplete follow-up in a limited number of patients. However, a few studies examined results of more than 20 patients at a mean follow-up of 2 years or longer.[106, 109, 112, 113, 123] The pressure gradients across the coarctation site (blood pressure, Doppler, or catheterization) remained low, and systemic hypertension decreased both in degree and frequency with the consequent decrease in the need for antihypertensive medications. No evidence for recoarctation, aneurysmal formation, or stent fracture or displacement was observed in most studies, although no systematic or complete follow-up was achieved in most studies. In some studies new aneurysms (in 6% of patients), stent fractures and jailed or partially covered brachiocephalic vessels were seen.[126]

Residual or recurrent obstruction was present in a few patients, and, in these, successful redilatation with larger balloons was accomplished. Detailed angiographic studies by Suarez de Lezo et al (1999) revealed no detectable neointimal proliferation in 75% of patients; in the remaining patients, focal neointimal ridge formation was observed at the ends of the stent, causing minimal restenosis.[106] Segmental analysis of the aorta revealed an increase in nonstented segments of the aorta, consistent with normal growth. Two young patients (7%) developed small new aneurysms that were obliterated by coil placement following angiographic detection. However, the overall follow-up results were encouraging.

Comments

Note the following:

  • Stent therapy appears to be an attractive method for the treatment of recurrent coarctation or aneurysm formation following prior surgical or balloon intervention and for long-segment hypoplasia. Most cardiologists use stents in adolescents and adults, although a few have advocated their use in younger children.[106, 127, 128] The selection of the type of stent and the type of balloon catheter used for stent deployment appears to be evolving. Balloon-expandable stents are preferred over self-expandable stents. However, some workers used self-expandable stents successfully.[129]

  • The use of a BIB catheter for stent delivery appears to be gaining momentum in an attempt to prevent balloon ruptures and perforation of other cardiovascular structures.

  • Positioning the guide wire into the right or left subclavian artery may avoid excessive curvature and, thus, may prevent balloon rupture.

  • Flexible instead of rigid Palmaz stents are being used.

  • Selected stent diameter at implantation should be at least twice the diameter of the narrowest aortic segment to prevent stent displacement during implantation.

  • The issues related to placement of the stent across the mouths of the arch vessel still need to be resolved.

  • Relief of obstruction both short-term and at follow-up with a low incidence of major complications is well demonstrated in several studies.

  • Meticulous attention to the technique and adoption of new technology, when it becomes available, may further reduce the incidence of complications.

  • Recoarctation rate at follow-up appears to be low. Re-expansion of the stent to treat residual or recoarctation and growth-related narrowing appears feasible, safe, and effective, although this is based on limited experience.[130]

  • The few studies that have compared balloon angioplasty with stents suggest that stents may be more effective.[117, 131, 132] Similar comparison between surgery and stents indicate stenting for native coarctation of the aorta is an effective alternative to surgical intervention in older children.[133, 134]

  • Based on the available data, stenting aortic coarctation appears to be the preferred alternative to surgical or balloon therapy in adolescents and young adults.

Covered stents

Experience in the use of covered stents to manage aortic coarctation is limited.[126, 135, 136, 137, 138, 139, 140, 141] Different types of stents to treat aortic coarctation have been used and include Jostent grafts, C-P stents, and AneuRx. Although these stents are available outside the United States, none are yet approved for clinical use by the US Food and Drug Administration (FDA). However, customizing and off-label use of available endoluminal grafts are feasible, when necessary.[142] The indications for intervention are similar to those used for balloon angioplasty and deployment of the standard stent.

The indications for use of covered stents include postangioplasty aneurysm, tortuous aortic arch and isthmus, associated patent ductus arteriosus, prior surgical conduit, Takayasu arteritis, and extremely narrow (subatretic) coarcted segment. When the assessed risk for development of aneurysm or dissection is high, a covered stent should be used. The results of the limited use of covered stents appear to be good.[126, 135, 136, 137, 138, 139, 140, 141] Some of the stents can be expanded to only an 18-mm diameter. In addition, the stent shortens when expanded to larger diameters. Use of covered stents has another disadvantage in that the vessels that arise from the aorta are blocked.

Aortic rupture remains an important, though an infrequent, complication following primary stenting for aortic coarctation. Covered stents have been used to reduce this risk. However, aortic rupture has been reported even with covered stents.[143]

Renarrowing of covered stents has been reported, and data in limited number of patients suggest Covered Cheatham-Platinum stents can redilated.[144]

A comparison between bare and covered Cheatham-platinum stents in a randomized clinical trial of 120 patients, aged 23.60 ± 10.99 years at a follow-up duration of 31.1 ± 19.2 months revealed a higher prevalence of recoarctation in bare metal stents and greater occurrence of pseudoaneurysm in covered stents; neither of these achieved statistical significance, however. Number of subjects with normal blood pressure increased in both groups.[145] Collapse and infolding of the covered stents can occur with the use of covered stents, requiring placement of additional stents.[146, 96]

Based on the currently available data, the covered stents may be useful in highly selected patients with aortic coarctation.

Comparison of different treatment modalities

In a multi-institutional study of 350 patients, Forbes et al[147] compared surgery, balloon angioplasty, and stent implantation for treatment of native aortic coarctation and demonstrated improvement in all 3 groups both acutely and at follow-up. However, the stent group had fewer complications (compared with surgical and balloon angioplasty patients), shorter hospitalization (compared with surgical patients), and lower coarctation gradients at follow-up (compared with balloon patients), but had higher “planned” reintervention (compared with surgical and balloon patients).

The study[147] is flawed in that there were a disproportionally large number of patients in the stent group (217, stent; 61, balloon angioplasty; 72, surgery), small number of patients followed (35.7%, with less than 75% of these patients having had imaging studies), and presumed noninclusion of all eligible patients into the study. Significant age and weight differences (P< .001) between study groups were found, although the authors attempted to address this issue by including an analysis of a subgroup of patients aged 6-12 years. Equally disturbing is the nonrandomized nature of the study. The authors, however, correctly concluded that these results should be interpreted with caution, which could be amended to “great” caution.

Instead of debating which treatment is better, it is prudent to tailor the treatment depending on the age of the patient and the pathology (anatomy) of the coarctation and the surrounding region. Most cardiologists prefer surgical intervention for treatment of neonatal and infant (< 1 y) coarctations. Children older than 1 year with discrete native coarctation are candidates for balloon dilatation. If the coarctation segment is long, surgical treatment in younger children and stents in adolescents and adults would seem appropriate.

Future directions

Causes of recoarctation following balloon angioplasty have been extensively investigated,[82, 148, 149] and factors predictive of recoarctation have been identified and include young age and severely narrowed isthmus and coarcted segment. More recently, studies of biophysical characteristics of the coarcted segment revealed less recoil in the subset of recoarctation patients, implying that the elastic properties of the aortic wall are not preserved.[150] This may be related to cystic medial necrosis[151, 152] or to extension of the ductal tissue into the aortic wall.[152, 153, 154]

However, the true cellular pathophysiologic mechanisms responsible for recoarctation have not been identified. Once they are identified, appropriate treatment algorithms to prevent recoarctation could be developed to address the pathophysiology. Until such time, keeping coarcted segments open with stents is an attractive option. Unfortunately, the stents, which are metallic, do not grow with the child and cannot be used routinely in neonates and infants.

Biodegradable stents[155, 156] may offer a solution; these stents keep the coarcted aortic segment open for a 3-month to 6-month period, after which the stents dissolve. By then, the ratio of the normal aortic tissue to abnormal tissue may be in favor of the infant, thus preventing recurrence of significant narrowing. However, this hypothesis should be tested in appropriate animal models and stent delivery systems miniaturized so that they can be used in neonates and young infants. Similarly growth stents[157] may allow re-dilatation at a later date.

Summary of treatment

At initial presentation, if cardiac failure or hypertension is the presenting problem, it should be addressed to stabilize the patient. Subsequently, the aortic obstruction should be relieved. The available options include surgical and catheter interventional procedures; the latter procedures include balloon angioplasty and bare or covered stents.

In general, surgical intervention in neonates and young infants (extremely ill babies with poor left ventricular function may benefit from balloon angioplasty), balloon angioplasty in children, and stent deployment in adolescents and adults appear to be appropriate options. Of course, the anatomy of the coarcted aortic segment and the aortic arch would greatly influence the method of therapy in a given patient.

Consultations

Early presentation

In infants who present early with CHF, stabilization in the ICU may be required prior to surgical intervention.

In premature infants, consultation with a neonatologist may be required to manage associated diseases related to prematurity, such as hyaline membrane disease.

Consultation with a geneticist may be indicated if Turner syndrome or other genetic conditions are suspected.

Consultation with a nephrologist may be needed for assistance in treating patients with hypertension in preoperative or postoperative acute renal failure.

Late presentation

Older patients may be initially referred to specialists prior to the diagnosis of coarctation of the aorta. Referral to a hypertension clinic may lead to the diagnosis of coarctation of the aorta by the nephrologist. Patients who undergo evaluation for suspected genetic syndromes may be referred to the cardiologist for evaluation because of previously undiagnosed coarctation.

Complications of coarctation of the aorta, such as intracranial hemorrhage or endocarditis, may require consultation with a neurosurgeon or infectious disease specialist, respectively.

Diet

Persistent hypertension has been shown to increase the incidence of coronary artery disease (CAD); therefore, periodically examine patients who have undergone coarctation of the aorta repair for hypertension and recommend a healthy low-fat, and perhaps, low-salt diet.

Measure cholesterol levels and intervene pharmacologically in older patients as indicated, with a total cholesterol goal of less than 200 g/dL.

Patients with persistent hypertension may require varying degrees of salt restriction.

Emphasize dietary counseling and avoidance of obesity and smoking.

Activity

Patients with coarctation of the aorta and hypertension who are awaiting surgical repair should limit heavy isometric exercises to a degree commensurate with the degree of hypertension.

Generally, the duration of hypertension after coarctation of the aorta repair is related in part to the duration of hypertension prior to diagnosis and repair of coarctation. Patients who undergo repair of coarctation in infancy usually remain normotensive in the absence of significant residual arch obstruction and require no specific activity restrictions or limitations. With growth, coarctation may recur, and some patients may be normotensive at rest but have significant upper extremity hypertension provoked by exercise. Such patients who desire to participate in competitive athletics should undergo exercise stress testing prior to clearance.

Patients who undergo repair later in life and who have had a significant period of preoperative hypertension are at particular risk for sustained postoperative hypertension, which may be permanent. Restrict heavy isometric exercise and other activities in these patients, commensurate with the degree of hypertension and BP control. Use exercise testing to assess BP response to exercise as a means of delineating reasonable exercise limitations.

 

Guidelines

Guidelines Summary

2008 American College of Cardiology/American Heart Association (ACC/AHA) guidelines on coarctation of aorta in adults (adapted)

Recommendations for clinical evaluation and follow-up [185]

Class I recommendations are as follows:

  • Every patient with systemic arterial hypertension should undergo simultaneous palpation of the brachial and femoral pulses to assess timing and amplitude evaluation to search for the brachial-femoral delay of significant aortic coarctation. Search for differential pressure by measuring the supine bilateral arm (brachial artery) blood pressures and prone right or left supine (popliteal artery) blood pressures (level of evidence: C)

  • For suspected aortic coarctation, useful initial imaging and hemodynamic evaluation is by transthoracic echocardiogram, including suprasternal notch acoustic windows (level of evidence: B)

  • All patients with coarctation (repaired or not) should have at least one cardiovascular magnetic resonance imaging (MRI) or computed tomography (CT) scan for complete evaluation of the thoracic aorta and intracranial vessels (level of evidence: B)

Medical therapy management strategies

Management of hypertension included first-line pharmacotherapy with beta blockers, angiotensin-converting enzyme inhibitors, or angiotensin-receptor blockers. Selection of beta blockers or vasodilators are based in part on the aortic root size, the presence of aortic regurgitation, or both.

Recommendations for interventional and surgical treatment

Class I recommendations are as follows:

  • Intervention for coarctation is recommended in the following circumstances: (1) Peak-to-peak coarctation gradient of at least 20 mm Hg (level of evidence: C) and (2) peak-to-peak coarctation gradient below 20 mm Hg in the presence of anatomic imaging evidence of significant coarctation with radiologic evidence of significant collateral flow (both level of evidence: C)

  • Selection of percutaneous catheter intervention versus surgical repair of native discrete coarctation should be determined by multi-team consultation with adult congenital heart disease cardiologists, interventionalists, and surgeons at the adult congenital heart disease center (ACHD) (level of evidence: C)

  • Percutaneous catheter intervention is indicated for recurrent, discrete coarctation and a peak-to-peak gradient of at least 20 mm Hg (level of evidence: B)

  • Experienced surgeons in congenital heart disease should perform operations for previously repaired coarctation as well as (1) long recoarctation segment and (2) concomitant hypoplasia of the aortic arch (both level of evidence: B)

Class IIb recommendation

Although stent placement for long-segment coarctation may be considered, its usefulness is not well established and the long-term efficacy and safety are unknown (level of evidence: C).

Recommendations for key issues for evaluation and follow-up

Class I recommendations are as follows:

  • Lifelong cardiology follow-up for all patients with aortic coarctation (repaired or not), including an evaluation by or consultation with a cardiologist with expertise in ACHD (level of evidence: C)

  • At least yearly follow-up for patients who have had surgical repair of coarctation at the aorta or percutaneous intervention for aortic coarctation (level of evidence: C)

  • Late postoperative thoracic aortic imaging to assess for aortic dilatation or aneurysm formation, even if the coarctation repair appears to be satisfactory (level of evidence: B)

  • Close observation for the appearance or reappearance of resting or exercise-induced systemic arterial hypertension, which should be treated aggressively after excluding recoarctation (level of evidence: B)

  • 5-Year or shorter interval evaluation of the coarctation repair site by MRI/CT scan, depending on the specific anatomic findings before and after repair (level of evidence: C)

Class IIb recommendation 

Routine exercise testing may be performed at intervals determined by consultation with the regional ACHD center (level of evidence: C).

For the full guidelines, see ACC/AHA 2008 Guidelines for the Management of Adults With Congenital Heart Disease.[185]

2014 European Society of Cardiology (ESC) guidelines

The ESC guidelines largely agree with the ACC/AHA recommendations (all level of evidence: C).[186]

Their class I recommendation is for intervention in all patients with a noninvasive pressure difference above 20 mm Hg between the upper and lower limbs, regardless of symptoms but with upper limb hypertension (>140/90 mm Hg in adults), abnomal exercise blood pressure response, or significant left ventricular hypertrophy.

Their class IIa recommendation indicates intervention should be considered in hypertensive patients with more than 50% aortic narrowing relative to the aortic diameter at the level of the diaphragm (as seen on MRI, CT scan, or invasive angiography), regardless of the pressure gradient.

Their class IIb recommendation  indicates intervention may be considered in patients with more than 50% aortic narrowing relative to the aortic diameter at the level of the diaphragm (as seen on MRI, CT scan, or invasive angiography), regardless of the pressure gradient and the presence of hypertension.

 

 

Medication

Medication Summary

The goals of pharmacotherapy are to reduce morbidity and to prevent complications of coarctation of the aorta (CoA).

Prostaglandins

Class Summary

Alprostadil (PGE1) promotes dilatation of the ductus arteriosus in infants with ductal-dependent cardiac abnormalities.

Alprostadil IV (Prostin VR Pediatric Injection)

Identical to the naturally occurring prostaglandin E1 (PGE1) and possesses various pharmacologic effects, including vasodilation and inhibition of platelet aggregation.

First-line medication used as palliative therapy to temporarily maintain patency of the ductus arteriosus before surgery. Beneficial in infants with congenital defects that restrict pulmonary or systemic blood flow and in patients who depend on a PDA for adequate oxygenation and lower-body perfusion. Produces vasodilation and increases cardiac output. Each 1-mL ampule contains 500 mcg/mL.

Inotropic agents

Class Summary

These agents are used to stimulate alpha-receptor and beta-receptors in the heart and vascular bed. Positive inotropic agents increase the force of contraction of the myocardium and are used to treat acute and chronic CHF. Some may also increase or decrease the heart rate (ie, positive or negative chronotropic agents), provide vasodilatation, or improve myocardial relaxation. These additional properties influence the choice of drug for specific circumstances.

Dopamine (Intropin)

Stimulates both adrenergic and dopaminergic receptors. Hemodynamic effects depend on the dose. Lower doses stimulate mainly dopaminergic receptors that produce renal and mesenteric vasodilation. Cardiac stimulation and renal vasodilation are produced by higher doses.

Positive inotropic agent at 2-10 mcg that can lead to tachycardia, ischemia, and dysrhythmias. Doses >10 mcg cause vasoconstriction, which increases afterload.

Dobutamine (Dobutrex)

Produces vasodilation and increases the inotropic state. At higher doses, may cause increased heart rate, thereby exacerbating myocardial ischemia. Strong inotropic agent with minimal chronotropic effect and no vasoconstriction.

Cardiac glycosides

Class Summary

These medications improve ventricular systolic function by increasing the calcium supply available for myocyte contraction.

Digoxin (Lanoxin)

This form inhibits the sodium-potassium ATPase pump in cardiac myocytes.

Diuretic agents

Class Summary

These agents promote excretion of water and electrolytes by the kidneys. They are used to treat heart failure or hepatic, renal, or pulmonary disease when sodium and water retention have resulted in edema or ascites. Generally includes a loop diuretic that inhibits sodium chloride reabsorption in the ascending loop of Henle.

Furosemide (Lasix)

Increases excretion of water by interfering with chloride-binding cotransport system, which, in turn, inhibits sodium chloride reabsorption in the ascending loop of Henle and distal renal tubules. Dose must be individualized to patient. Depending on response, administer at increments no sooner than 6-8 h after the previous dose, until desired diuresis occurs.

Beta-adrenergic blocking agents

Class Summary

These agents inhibit chronotropic, inotropic, and vasodilatory responses to beta-adrenergic stimulation. Preoperative hypertension can be treated effectively with beta-blockers.

Metoprolol (Lopressor)

Selective beta1-adrenergic receptor blocker that decreases automaticity of contractions. During IV administration, carefully monitor BP, heart rate, and ECG. When considering conversion from IV to PO dosage forms, use ratio of 2.5 mg PO to 1 mg IV metoprolol.

Esmolol (Brevibloc)

Ultra–short-acting beta2-blocker. Particularly useful in patients with labile arterial pressure, especially if surgery is planned, because it can be discontinued abruptly, if necessary. May be useful as a means to test beta-blocker safety and tolerance in patients with history of obstructive pulmonary disease who are at uncertain risk for bronchospasm from beta-blockers. Elimination half-life is 9 min.

Labetalol (Normodyne, Trandate)

Blocks alpha-aderenergic, beta1-aderenergic, and beta2-aderenergic receptor sites, decreasing BP.

Propranolol (Inderal, Betachron E-R)

Class II antiarrhythmic nonselective beta-adrenergic receptor blocker. Has membrane-stabilizing activity and decreases automaticity of contractions. Not suitable for emergency treatment of hypertension.

Atenolol (Tenormin)

Selectively blocks beta1-receptors with little or no effect on beta2-receptors.

Angiotensin-converting enzyme (ACE) inhibitors

Class Summary

These agents reduce afterload and decrease myocardial remodeling that worsens chronic heart failure. May be added if hypertension persists despite beta-blocker therapy and no residual arch obstruction is noted.

Captopril (Capoten)

ACE inhibitors decrease the production of angiotensin II, a potent vasoconstrictor, resulting in peripheral vasodilatation and afterload reduction, improved myocardial performance, and theoretically reduced atrioventricular and semilunar valve insufficiency.

Enalapril (Vasotec)

Competitive ACE inhibitor with prolonged duration of action with oral administration.

Reduces angiotensin II levels, reducing aldosterone secretion.

Vasodilators

Class Summary

Postoperative hypertension can be treated short-term with vasodilators, which reduce SVR, allowing more forward flow, thus improving cardiac output.

Nitroprusside (Nitropress)

Directly acting vasodilator. Exerts its effect on both arterial and venous circulation. Causes reflex tachycardia, small decrease in cardiac output, and decreases total peripheral resistance and cardiac and stroke index.

 

Follow-up

Further Outpatient Care

Focus early outpatient follow-up care on wound healing, resolution of lung atelectasis, and adjustment of antihypertensive medications.

Assess postoperative BP response to exercise prior to discontinuation of antihypertensive therapy.

Many patients may be weaned from antihypertensive therapy over months or years following repair of coarctation. Other patients may require some form of ongoing antihypertensive therapy.

Search for late complications of coarctation repair, including recurrent coarctation and aneurysm formation.

Patients should receive antibiotic prophylaxis before undergoing any bacteremia-producing surgery or procedures, especially in view of reported incidence of bacterial endocarditis during follow-up.[158]

Further Inpatient Care

Focus postoperative recovery of patients with coarctation of the aorta (CoA) on control of blood pressure (BP), slow advancement of diet, manipulation of antihypertensive medications, progressive ambulation, and pulmonary therapy to improve left lung atelectasis (common after left thoracotomy).

Hospitalization and inpatient care may be required for cardiac catheterizations, catheter interventions, and surgical procedures for treatment of recoarctation or other complications.

Transfer

If coarctation of the aorta is prenatally diagnosed, the mother should deliver at or near a facility with expertise in caring for an infant with coarctation of the aorta. The facility should also have prostaglandin E1 available.

Infants who present early with severe coarctation of the aorta may require transfer to a facility with pediatric cardiologists and cardiovascular surgeons skilled in the management of coarctation in seriously ill infants.

Consider transfer of older children, adolescents, and adults to a facility with cardiologists and surgeons with experience in the management of coarctation.

Deterrence/Prevention

Although coarctation of the aorta cannot be prevented, it can be detected early with fetal echocardiography. Although the diagnosis can be difficult to make, echocardiography may be considered in fetuses with unexplained enlargement of the right ventricle, difficult identification of the true aortic arch, identification of an unusual aortic arch contour, or identification of anomalies that may be associated with coarctation of the aorta, such as other forms of left heart obstruction. Fetal echocardiography is indicated during pregnancy in every woman who has previously borne a child with congenital heart disease (CHD), especially left heart obstructive lesions.

Postnatally, early detection of coarctation of the aorta is important to avoid prolonged hypertension or other complications. Careful measurement of BPs and evaluation of lower extremity pulses in newborns and at subsequent healthy child examinations is imperative.

Patient Education

Educate patients with coarctation of the aorta and their families regarding the need for lifelong follow-up care to detect recurrent coarctation or late complications.

Educate patients regarding a healthy lifestyle by instructing them to avoid smoking and obesity, get plenty of aerobic exercise, control BP appropriately, and reduce other factors that influence cardiovascular disease.

 

Questions & Answers

Overview

How common is congenital coarctation of the aorta (CoA)?

What is coarctation of the aorta (CoA)?

What is the pathologic anatomy of coarctation of the aorta (CoA)?

Which clinically significant defects are associated with coarctation of the aorta (CoA)?

What is the pathogenesis of coarctation of the aorta (CoA)?

What is the pathophysiology of coarctation of the aorta (CoA)?

What is the mechanical obstruction theory of coarctation of the aorta (CoA)?

What is the humoral theory of coarctation of the aorta (CoA)?

What is the role of associated anomalies in the pathophysiology of coarctation of the aorta (CoA)?

Which cardiac drugs may be implicated in the pathophysiology of coarctation of the aorta (CoA)?

How might trauma be a factor in coarctation of the aorta?

What is the prognosis of coarctation of the aorta (CoA)?

What is the role of restrictive LV physiology the prognosis of coarctation of the aorta (CoA)?

What is the morbidity and mortality of coarctation of the aorta (CoA)?

What are complications in coarctation of the aorta (CoA)?

How is recurrent coarctation of the aorta (CoA) characterized?

How is aortic aneurysm in coarctation of the aorta (CoA) characterized?

Why does hypertension persist following repair of coarctation of the aorta (CoA)?

What causes cerebral aneurysms in coarctation of the aorta (CoA)?

What causes paralysis in coarctation of the aorta (CoA)?

How is cardiomyopathy characterized in coarctation of the aorta (CoA)?

What is chylothorax in coarctation of the aorta (CoA) repair?

What is postcoarctectomy syndrome in coarctation of the aorta (CoA) repair?

When do valvar aortic stenosis, membranous subaortic stenosis, and mitral valve stenosis complications occur in coarctation of the aorta (CoA) repair?

Does coarctation of the aorta (CoA) have a racial predilection?

Is coarctation of the aorta (CoA) more common in males or females?

What are the age demographics of coarctation of the aorta (CoA)?

How common is coarctation of the aorta (CoA) in the US?

What is the international prevalence of coarctation of the aorta (CoA)?

Presentation

How is the presentation of coarctation of the aorta (CoA) characterized?

What are the features of early presentation of coarctation of the aorta (CoA)?

What are the features of late presentation of coarctation of the aorta (CoA)?

What are the physical findings in coarctation of the aorta (CoA)?

What are the physical findings in the early presentation of coarctation of the aorta (CoA)?

What are the physical findings in the late presentation of coarctation of the aorta (CoA)?

What causes coarctation of the aorta (CoA)?

DDX

What are the diagnostic considerations in coarctation of the aorta (CoA)?

What are the special considerations in pregnant patients with a history of coarctation of the aorta (CoA)?

What are the differential diagnoses for Coarctation of the Aorta?

Workup

Which lab studies are indicated in the workup of coarctation of the aorta (CoA)?

What is the role of ECG in the workup of coarctation of the aorta (CoA)?

What is the role of chest radiography in the workup of coarctation of the aorta (CoA)?

What is the role of echocardiography in the workup of coarctation of the aorta (CoA)?

What is the role of MRI and CT scanning in the workup of coarctation of the aorta (CoA)?

What is the role of cardiac catheterization in the workup of coarctation of the aorta (CoA)?

What are the histologic findings in coarctation of the aorta (CoA)?

Treatment

What is the medical care in the early presentation of coarctation of the aorta (CoA)?

What is the medical treatment for hypertension in a late presentation of coarctation of the aorta (CoA)?

Which cardiac abnormalities are associated with coarctation of the aorta (CoA)?

What is the role of evaluating the adequacy of the collateral blood vessels in the surgical repair of coarctation of the aorta (CoA)?

How effective are stents in the repair of coarctation of the aorta (CoA)?

When is surgery indicated in the treatment of coarctation of the aorta (CoA)?

Which surgical techniques are used in the repair of coarctation of the aorta (CoA) in infancy and what are the outcomes?

How effective is surgical repair of coarctation of the aorta (CoA)?

What are the long-term results of surgical intervention in coarctation of the aorta (CoA)?

When is balloon angioplasty indicated in the treatment of coarctation of the aorta (CoA)?

What is the technique for balloon angioplasty in the surgical repair of coarctation of the aorta (CoA)?

What are the short-term results of balloon angioplasty in the repair of coarctation of the aorta (CoA)?

What are the intermediate-term results of balloon angioplasty in the repair of coarctation of the aorta (CoA)?

What are the long-term results of balloon angioplasty in the repair of coarctation of the aorta (CoA)?

Is balloon angioplasty used in the repair coarctation of the aorta (CoA) in adults?

How do surgery and balloon angioplasty compare in the repair of coarctation of the aorta (CoA)?

What are the complications of surgical repair in coarctation of the aorta (CoA)?

What studies investigated the efficacy of balloon angioplasty for the treatment of coarctation of the aorta (CoA)?

How does recoarctation occur following repair of coarctation of the aorta (CoA)?

When is balloon angioplasty the treatment of choice for coarctation of the aorta (CoA)?

What is the role of aortic stents in the repair of coarctation of the aorta (CoA)?

What are the advantages of stents over balloon angioplasty for the repair of coarctation of the aorta (CoA)?

What are the indications for stents in the repair of coarctation of the aorta (CoA)?

What are the procedures for inserting a stent in the repair of coarctation of the aorta (CoA)?

What are the immediate results of aortic stents in the repair of coarctation of the aorta (CoA)?

What are complications of stent repair for coarctation of the aorta (CoA)?

What are the long-term outcomes of stents in coarctation of the aorta (CoA) repair?

What are the pearls of surgical repair of coarctation of the aorta (CoA)?

What are the indications for covered stents in coarctation of the aorta (CoA) repair?

What is the best option for repair of coarctation of the aorta (CoA)?

What are the future directions of treatment of coarctation of the aorta (CoA)?

Which interventions are best for coarctation of the aorta (CoA) by age?

Which specialist consultations are indicated for neonates with coarctation of the aorta (CoA)?

Which specialist consultations are indicated in late presentations of coarctation of the aorta (CoA)?

What is the recommended diet for patients with coarctation of the aorta (CoA)?

What is the recommended level of activity for patients with coarctation of the aorta (CoA)?

Medications

What are the goals of drug treatment in coarctation of the aorta (CoA)?

Which medications in the drug class Vasodilators are used in the treatment of Coarctation of the Aorta?

Which medications in the drug class Angiotensin-converting enzyme (ACE) inhibitors are used in the treatment of Coarctation of the Aorta?

Which medications in the drug class Beta-adrenergic blocking agents are used in the treatment of Coarctation of the Aorta?

Which medications in the drug class Diuretic agents are used in the treatment of Coarctation of the Aorta?

Which medications in the drug class Cardiac glycosides are used in the treatment of Coarctation of the Aorta?

Which medications in the drug class Inotropic agents are used in the treatment of Coarctation of the Aorta?

Which medications in the drug class Prostaglandins are used in the treatment of Coarctation of the Aorta?

Follow-up

What is the follow-up care of patients with coarctation of the aorta (CoA) repair?

What is the postsurgical inpatient care for patients with coarctation of the aorta (CoA)?

When is transfer indicated for patients with coarctation of the aorta (CoA)?

Can coarctation of the aorta (CoA) be prevented?

What education should be provided to patients with coarctation of the aorta (CoA)?