Coronary Artery Anomalies 

Updated: Dec 30, 2019
Author: Louis I Bezold, MD; Chief Editor: Stuart Berger, MD 

Overview

Background

Knowledge of physiology, normal and variant anatomy, and anomalies of coronary circulation is an increasingly vital component in managing congenital and acquired pediatric heart disease. Congenital, inflammatory, metabolic, or degenerative disease may involve coronary circulation, and increasingly complex cardiac surgical repairs demand enhanced understanding to improve operative outcomes.

Variations in coronary anatomy are often recognized in association with structural forms of congenital heart disease. Importantly, coronary artery anomalies are a cause of sudden death in young athletes in the absence of additional heart abnormalities. Understanding the pathophysiology is important in guiding management because variations in coronary anatomy are common. Because of considerable heterogeneity of coronary vasculature, what is considered atypical, abnormal, aberrant, anomalous, accessory, ectopic, incidental, variant, or significant is often unclear. The terms anomalous or abnormal are used to define any variant form observed in less than 1% of the general population.

The Latin term corona, or crown, aptly describes coronary arteries that supply cardiac parenchyma with nutrient blood flow. Coronary arteries (most often two) are normally the only vessels arising immediately above the free margin of aortic valve from the ascending aorta. The name and nature of a coronary artery or branch is defined by that vessel's distal vascularization pattern or territory, rather than by its origin. The right coronary artery (RCA) most commonly arises separately from an ostium just below the sinotubular junction of the right (right anterior) sinus of Valsalva. The normal anatomy of the coronary arteries is shown in the image below.

Normal anatomy of coronary arteries, viewed from a Normal anatomy of coronary arteries, viewed from above with the atria removed. A = aortic valve; P = pulmonary valve; T = tricuspid valve; M = mitral valve; RCA = right coronary artery; AM = acute marginal branch of the right coronary artery; CB = conus branch of the right coronary artery; PD = posterior descending branch; AVN = atrioventricular nodal branch; Circ = circumflex coronary artery; OM = obtuse marginal branches of circumflex coronary artery; LAD = left anterior descending coronary artery; Diag = diagonal branches of the left anterior descending coronary artery; Inter = intermedius branch of the left coronary artery.

The RCA courses in the right atrioventricular groove and provides nutrient branches to the right ventricular free wall, extending to the acute margin of the heart. The distal extent of the RCA varies and may extend posteriorly as far as the obtuse margin of the heart. In 90% of patients, the RCA supplies the posterior descending coronary artery branch at the crux of the heart, which supplies the atrioventricular (AV) node and the posterior aspect of the interventricular septum.

The first branch arising from the RCA is the conal or infundibular branch, which courses anteriorly to supply the muscular right ventricular outflow tract or infundibulum. The RCA supplies blood to the atria with a highly variable pattern of small branches. The sinus node artery arises from the proximal RCA in approximately 50% of patients. The left coronary artery (LCA) arises from the mid position of the left (left anterior) sinus of Valsalva (sinuses on either side of the point of aortic and pulmonary commissural contact) just above the level of the free margin of the aortic valve leaflet and generally below the sinotubular junction.

The left coronary ostium is usually single, giving rise to a short, common LCA trunk that branches into the left anterior descending (LAD) and circumflex (Cx) coronary arteries. The LAD courses in the anterior interventricular groove, giving rise to the anterior septal perforating branches as it extends toward the cardiac apex. Small branches may arise from the LAD and supply the anterior wall of the right ventricle. Diagonal branches arise from the LAD and course at downward angles to supply the anterolateral free wall of the left ventricle.

The Cx coronary artery courses along the left AV groove, around the obtuse margin, and posteriorly toward the crux of the heart. Should the Cx coronary reach the crux of the heart and supply the posterior descending coronary artery, the left coronary system would be termed dominant. This occurs in approximately 10% of patients. Atrial branches may arise from the Cx coronary artery and supply the sinus node in 40% of patients. Obtuse marginal branches arise from the Cx system to supply the posterolateral aspect of the left ventricle. In an estimated 70% of patients, a coronary branch (termed ramus medianus, intermedius, or intermediate branch) arises early off the left coronary system to supply an area between diagonal branches from the LAD and obtuse branches from the Cx systems.

Variability in coronary circulation

Despite the position of the heart within the chest and the position of the great arteries as they arise from the heart, aortic and pulmonary valves normally have a single point of contact, with commissural apposition at this point. Coronary arteries almost always arise normally from the "facing" sinuses of Valsalva on either side of this point of commissural contact. Coronary arteries do not normally arise from "nonfacing" or most distant sinus; however, variations in coronary anatomy are common. Variations that occur in less than 1% of the general population may be considered abnormal or anomalies.[1, 2] Coronary artery development, both normal and abnormal, has been reviewed in recent years.[3]

Number and size of coronary ostia

Normally, an individual has two or, sometimes, three coronary ostia. Often, the conal branch of the RCA may arise separately from the right sinus. The Cx or LAD may, on occasion, arise directly from the aortic root. Coronary ostia are typically equal to, or larger than, the vessel they supply.

Positioning within sinuses

Coronary arteries arise more or less perpendicular to the aortic wall. Ostia are located in the middle of the sinus, just above the free leaflet margin of the aortic leaflet and below the sinotubular junction. Coronary arteries that arise ectopically usually course tangentially to the aortic wall or arise in close relationship to the commissure of the aortic valve.

Course of coronary arteries

The course of named coronary arteries is mostly epicardial, although the proximal LAD may have an intramural or subepicardial course in 5-25% of the general population. Branches of epicardial vessels generally proceed in a perpendicular course to supply myocardial arterioles and capillaries. This uniquely designed pattern of epicardial (reservoir) and intramyocardial (nutrient) supply optimizes blood flow to the heart.

Patient education

For patient education resources, see Heart Health Center as well as Tetralogy of Fallot.

Pathophysiology

The heart has a very limited capacity for anaerobic metabolism. The primary source of energy is oxidative metabolism of free fatty acids; therefore, the heart has a negligible ability to tolerate periods of ischemia, yet its capacity to extract oxygen is great (although relatively fixed), and limited degrees of hypoxemia are generally well tolerated. At rest, the oxygen requirement of the heart (8-10 mL/min/100 g) is much greater than of the skeletal muscle (0.115 mL/min/100 g). Exercise requires a 50% increase in oxygen demand primarily met by an increase in myocardial flow 3-4.5 times greater than baseline.

The pattern of coronary blood flow is unique. Epicardial coronary vessels serve as capacitance vessels, primarily filling during the period of diastole (as much as 85% of total flow), and intramural pressure and resistance to myocardial perfusion progressively increase from the outer to inner layers of the heart. Myocardial arterioles have tremendous vasodilatory reserve capacity and enable high flow and low resistance in response to exercise. Recent investigations suggest that the coronary vascular tree has a dual mechanism of vasodilatation: larger proximal vessels by endothelium-derived nitric oxide and direct stimulation of smooth muscle cell alpha2-receptors by adenosine and other metabolites.[4]

A coronary artery with an oblique origin, intramural (within the wall of the aorta) course, or positioning between the great arteries puts the coronary arteries at risk for compression and may significantly limit the reservoir capacity of the epicardial coronary system. Comparable pressure in larger vessels creates greater wall tension and is felt to cause compression of smaller vessels that are in continuity by the Laplace law (tension = pressure X radius).

Proximal areas of significant stenosis hamper the heart's capacity to respond to increased myocardial oxygen demands. The major regulators of coronary blood flow are as follows:

  • Intramural pressure

  • Aortic diastolic perfusion pressure

  • Myocardial metabolic rate (in turn related to heart rate, inotropic state, and systolic arterial pressure)

  • Autonomic nervous system control

  • Endothelial function

  • Blood viscosity in response to decreased myocardial oxygen supply

Myocardial ischemia is the primary manifestation of congenital or acquired coronary artery disease (CAD).

In Coronary Artery Anomalies, Angelini comprehensively classifies coronary anomalies in (normal) human hearts, as follows[5] :

  • Anomalies of origination and course

  • Anomalies of intrinsic coronary arterial anatomy

  • Anomalies of coronary termination

  • Anomalous collateral vessels

Anomalies of origination and course

Anomalies of origination and course include the following[6] :

  • Absent left main trunk (split origination of the left coronary artery [LCA])

  • Anomalous location of coronary ostium within aortic root or near proper aortic sinus of Valsalva (for each artery): High, low, commissural

  • Anomalous location of coronary ostium outside normal "coronary" aortic sinuses

  • Anomalous origination of the coronary ostium from opposite, facing "coronary" sinus (potentially involves joint origination or adjacent double ostia) Variants include the following: (1) the right coronary artery (RCA) arising from the left anterior sinus, with anomalous course; (2) the left anterior descending (LAD) coronary artery arising from right anterior sinus, with anomalous course; (3) the circumflex artery arising from the right anterior sinus, with anomalous course; and (4) the LCA arising from the right anterior sinus, with anomalous course

  • Single coronary artery

For more detailed information, please refer to Angelini P, Velasco JA, Flamm S. Coronary anomalies: incidence, pathophysiology, and clinical relevance. Circulation. 2002 May 21;105(20):2449-54. PMID: 12021235.[6]

Anomalies of intrinsic coronary arterial anatomy

Anomalies of intrinsic coronary arterial anatomy include the following:

  • Congenital ostial stenosis or atresia (LCA, LAD, RCA, Cx): Coronary ostial dimple, coronary ectasia or aneurysm

  • Absent coronary artery

  • Coronary hypoplasia

  • Intramural coronary artery (muscular bridge)

  • Subendocardial coronary course

  • Coronary crossing

  • Anomalous origination of posterior descending artery from anterior descending branch or septal penetrating branch

  • Absent PD (split RCA): Variants include proximal and distal PDs, both arising from the RCA

  • Absent LAD (split LAD): Variants include (1) LAD and a first large septal branch and (2) double LAD

  • Ectopic origination of first septal branch

Anomalies of coronary termination

Anomalies of coronary termination may include inadequate arteriolar/capillary ramifications as well as fistulas from the RCA, LCA, or infundibular artery to the following:

  • Right ventricle

  • Right atrium

  • Coronary sinus

  • Superior vena cava

  • Pulmonary artery

  • Pulmonary vein

  • Left atrium

  • Left ventricle

  • Multiple, right and left ventricles

Epidemiology

United States data

A higher incidence of coronary anomalies is observed in young victims of sudden death than in adults (4-15% vs 1%, respectively). Several large studies address the frequency of minor and major coronary anomalies in different subsets of patients by varying techniques and recording methods. Angelini's comprehensive review identified an incidence of coronary anomalies in 5.6% of consecutive patients undergoing angiographic study and is shown in the image below.[5]

Incidence of coronary artery abnormalities detecte Incidence of coronary artery abnormalities detected in 1,950 selective coronary angiograms performed in adult patients with suspected coronary arterial obstructive disease and otherwise anatomically normal hearts.

The most common coronary variants were split RCA (1.23%) and ectopic origin of the RCA near the right aortic sinus (1.13%). Many coronary variations, such as intramural extension or myocardial bridging of the LAD, which occurs in 5-25% of patients, are so common, they are not considered an anomaly.

Anomalous origins of the coronary arteries have been described in siblings,[7] and a recent study suggested a higher incidence of asymptomatic anomalous coronary origins in first-degree relatives of patients with an anomalous coronary, raising the question of whether screening family members should be considered.[8]

In a large retrospective incidence study, coronary artery anomalies were found in 1% of adults and 0.9% of children.[9] Anomalous left circumflex artery was the most common anomaly in adults (25%). The majority of adults were asymptomatic; anomalous left coronary artery from pulmonary artery and myocardial bridges were the only anomalies responsible for anginalike symptoms in adults. In children, anomalous left coronary artery from the pulmonary artery was most common (48%), it was generally detected due to symptoms, and it always required urgent surgical treatment.[9]

Race-, sex-, and age-related demographics

No racial or sexual predisposition is known.

Anomalous origin of the LCA from the pulmonary artery presents in early infancy. Significant coronary anomalies usually result in symptoms or sudden death in older children or young adults. Numerous incidental coronary anomalies may be detected at the time of coronary angiography in later adult life.

Prognosis

Morbidity/mortality

Many coronary anomalies are clinically silent and are recognized only at the time of autopsy. The incidence of incidental coronary anomalies at autopsy includes a single coronary artery in 0.024% and coronary arterial fistulae in 0.2%. After hypertrophic cardiomyopathy, coronary artery abnormalities are the second most common cause of sudden death in young athletes.

 

Presentation

History

Manifestations of coronary artery disease (CAD) reflect myocardial ischemia and are recognized clinically as the following:

  • Myocardial dysfunction

  • Angina

  • Syncope

  • Dysrhythmia

  • Infarction[10]

  • Death

Pediatric CAD usually presents in infancy as cardiogenic shock or later in childhood or adolescence as an activity-related phenomenon, syncope, or chest pain.

In infants, angina may be recognized by the following symptoms:

  • Irritability

  • Diaphoresis

  • Gray or poor color in association with symptoms

  • Poor output or congestive heart failure (CHF)

Most infants present at age 2-3 months with the following symptoms:

  • Poor feeding

  • Dyspnea

  • Wheezing

  • Periods of pallor

  • Failure to thrive

In the older child or adolescent, anginal chest pain or syncope associated with activity is suggestive of CAD.

Unfortunately, in a significant number of patients, symptoms may not be evident before a sudden catastrophic, presumably dysrhythmic, event. Ventricular dysrhythmias are usually the terminal event in these circumstances.

Sudden death is most often associated with activity. It is frequently observed in association with anomalous origin of the left coronary artery (LCA) from the right sinus of Valsalva and coursing between the two great arteries. In this circumstance, the coronary artery often has an oblique origin, slitlike ostia, and intramural and interarterial course.

Coronary ischemia is felt to arise from disturbed kinetics from oblique origin, ostial stenosis, compression of intramural course, loss of reservoir capacity, and increased myocardial oxygen demands associated with exercise.

Sudden death is less commonly seen in association with anomalous origin of the right coronary artery (RCA) from the left sinus of Valsalva. It has also been reported in association with ostial stenosis, atresia, or hypoplasia.

Physical Examination

In infancy with coronary ischemia, patients present with signs of CHF and low output. The apex beat is diffuse with a palpable or audible third heart sound (S3) gallop. Heart sounds are often reduced in intensity with a holosystolic murmur of mitral valve insufficiency audible at the apex. In the older child, physical examination findings vary from entirely normal (most often) to findings of cardiogenic shock caused by myocardial infarction (rare).

Older patients with a coronary arterial fistula may present with signs of CHF, a continuous murmur, and, rarely, endocarditis.

Causes

Associated syndromes

Coronary anomalies may be commonly associated with other congenital cardiac malformations, most notably, transposition of the great arteries, tetralogy of Fallot malformation, and different forms of pulmonary atresia. Each of these topics is addressed specifically in other chapters.

Williams syndrome

Patients with Williams syndrome (elfin facies, infantile hypercalcemia, hypoplastic teeth) may have coronary ostial narrowing as a component of supravalvar aortic stenosis characteristic of this disease. Patients with aortic valve disease commonly have variants in ostial origin. Those with varied forms of left ventricular outflow tract obstruction are at greater risk for increasing myocardial oxygen demand with limited ability to augment oxygen supply, placing them at increased risk for myocardial underperfusion.

D-transposition of the great arteries[11]

Coronary arteries in transposition of the great arteries normally arise from facing sinuses of Valsalva. Variation in coronary arterial patterning is frequent, and distribution of coronary pattern, as described by Sim et al, is presented in the image below.[12]

Thirteen patterns of origin and proximal epicardia Thirteen patterns of origin and proximal epicardial course of coronary arteries in 255 hearts with complete transposition of the great arteries. LAD = left anterior descending coronary artery; LCA = left coronary artery; LCx = left circumflex coronary artery; RCA = right coronary artery. (Image courtesy of Excerpta Medica, Inc).

Correct identification of the origin and course of coronary vasculature is important for patients undergoing Jatene arterial switch procedure. The presence of an intramural coronary artery course in this condition may complicate arterial switch operation.

According to Pasquini, this anomaly may be suggested on echocardiographic study by the eccentric origin of the coronary ostia arising away from the middle third of the aortic sinus and coursing within the aortic wall (see Transposition of the Great Arteries).[13]

Tetralogy of Fallot[11]

Operative repair of pulmonary outflow obstruction often involves patching of the right ventricular outflow tract and resection of the obstructing right ventricular muscle.[14]

An estimated 2-9% of patients with tetralogy of Fallot have coronary arterial anomalies, possibly affecting timing or approach to operative repair. The most common anomaly is origin of the left anterior descending (LAD) coronary artery from the RCA, which then courses across the pulmonary outflow tract. This is estimated to occur in approximately 4% of patients (see the image below.)

Thirteen patterns of origin and proximal epicardia Thirteen patterns of origin and proximal epicardial course of coronary arteries in 255 hearts with complete transposition of the great arteries. LAD = left anterior descending coronary artery; LCA = left coronary artery; LCx = left circumflex coronary artery; RCA = right coronary artery. (Image courtesy of Excerpta Medica, Inc).

Frequently, the conus branch of the RCA is large and supplies a significant portion of right ventricular infundibular muscle. Surgical techniques to avoid transection include limited incisions, varied tunneling techniques, and perhaps conduit placement. Cardiologists must predefine these abnormalities by noninvasive or invasive study (see Tetralogy of Fallot with Absent Pulmonary Valve, Tetralogy of Fallot with Pulmonary Atresia).

Pulmonary atresia with intact ventricular septum[11]

In this condition, absence of effective egress of blood from the cavity of the right ventricle may preserve primitive embryonic sinusoidal connections to coronary vasculature, resulting in the filling of the connections from the right heart in systole and filling from the aorta in diastole.

These abnormal right ventricular coronary sinusoidal connections can be recognized echocardiographically and angiographically.[15] The coronary vessel most often affected is the RCA, but the LAD system or, less frequently, the distal extent of the circumflex (Cx) coronary artery may also be affected. In addition, 70% of these coronary arteries may demonstrate severe intimal thickening, occlusion, or interruption.

In most cases, endocardial fibroelastosis, myocardial fibrosis, and acute myocardial infarction are observed. Optimal coronary arteriography often is required to delineate the extent of these abnormalities. Medical and surgical management strategies are varied and often ineffective (see Pulmonary Atresia with Intact Ventricular Septum).

Hypoplastic left heart syndrome and Shone complex

Clinically important anomalies of the left coronary system do occur in patients with left heart obstructive disease and can affect surgical approach and outcome, highlighting the importance of routinely attempting to identify coronary anatomy in pediatric patients with congenital heart disease.[11, 16]

Congenitally corrected transposition of the great arteries (atrioventricular and ventriculoarterial discordance

Congenitally corrected transposition of the great arteries (atrioventricular and ventriculoarterial discordance has much less variability of coronary anatomy than d-TGA. Most patients have so-called typical arrangement of the coronary origins; however, surgically important variations exist.[11]

Other forms of congenital heart disease

Other forms of congenital heart disease associated with coronary artery anomalies include truncus arteriosus, double outlet right ventricle, and bicuspid aortic valve.[11]

 

DDx

 

Workup

Laboratory Studies

In the initial evaluation of a critically ill infant, include an assessment of acid-base status and rule out systemic sepsis. Cardiac enzymes (creatine kinase [CK], lactate dehydrogenase [LDH], serum glutamic-oxaloacetic transaminase [SGOT], troponins) are elevated in association with muscle loss. Brain natriuretic peptide (BNP) may be obtained as an index of congestive heart failure (CHF).

In a typical patient with myocardial muscle damage, SGOT levels elevate within 6 hours of injury, peak at 2-10 times normal at 18-36 hours, and normalize within 3-4 days. In typical patients, LDH levels increase relatively late, peak in 3-6 days, and normalize within 8-14 days. The plasma CK levels exceed normal within 4-6 hours, peak within 24 hours, and decline to normal within 3-4 days.

In addition to the heart, skeletal muscle, smooth muscle, and the brain are endowed with CK, and diagnostic specificity is enhanced by reporting of isoenzymes. Isoenzymes of CK are dimers composed of muscle (M) or brain (B) subunits. MB isoenzyme fraction is only minimally present in tissues other than the heart; consequently, an elevation in CK-MB fraction represents myocardial cell death and is unlikely to be present with ischemia alone.

Because of their high specificity for both myocardial cell injury and infarction, cardiac troponins may allow for detection of minor cell damage and quantification of myocardial cell injury. Troponins are three distinct proteins (I, C, T) that regulate calcium-dependent interaction of myosin and actin. Troponin C is similar in myocardial and skeletal muscle; however, troponins I and T are unique to myocardium, and a sensitive enzyme-linked immunosorbent assay is currently available for clinical use.

Imaging Studies

Chest radiography

Radiographic features of anomalous coronary arteries are similar to those of CHF, including cardiomegaly, pulmonary venous congestion, interstitial edema, and left atrial enlargement.

Echocardiography

In patients sustaining myocardial injury, echocardiography demonstrates a hypocontractile, dilated, poorly functioning ventricle. Global or regional areas of myocardial dysfunction may be present. Mitral valve insufficiency from papillary muscle dysfunction is often demonstrable and may be recoverable.

Coronary arteries should be diligently sought in any patient presenting with cardiac dysfunction or in an older child presenting with activity-related chest pain. By routine evaluation of coronary arteries, chances for identification of coronary variants are increased.

Specific echocardiographic findings may include identification of the site of coronary artery origin with anomalous origin off pulmonary vasculature, which is associated with reciprocal dilatation and increased flow of corresponding coronary artery as it arises from the aorta. Septal collateral vessels often present as increased color flow signals within the interventricular septum. Transesophageal studies employing color Doppler assessment have been useful in identifying turbulent high-velocity flow in patients with coronary ostial stenosis.

Routine, systematic echocardiographic evaluation of coronary artery origins in a large cohort of asymptomatic patients suggests that clinically "silent" congenital coronary anomalies are more common than generally recognized, particularly high coronary takeoff, wrong sinus of origin, and small coronary artery fistulas. Associated congenital heart defects were found in 53% of individuals with coronary anomalies.[17] Recent description of a clinically unsuspected anomalous left coronary artery diagnosed via echocardiography in a premature infant underscores the importance of routinely identifying coronary artery origins on routine echocardiograms.[18]

Cardiac Magnetic Resonance Imaging (MRI)

Cardiac MRI allows noninvasive evaluation of cardiac structure, flow, and function (as is seen in the image below).

MRI of anomalous right coronary artery (RCA = blac MRI of anomalous right coronary artery (RCA = black arrow) arising from the left sinus of Valsalva and coursing interatrially between the aorta (AO) and the pulmonary artery (PA). Note the oblique origin and the intramural course within the aortic wall, all factors compromising coronary blood flow.

Newer MRI sequences have improved image quality with better anatomical definition. Cine MRI sequences are useful to show dynamics and flow disturbances. Black-blood imaging enables visualization of the lumen and aortic wall. Three-dimensional reconstruction provides optimal anatomical information.

MRI does not use radiation and enables adequate definition of the origin of the coronary vasculature but is limited by time of acquisition and gating requirements for cardiac study and may suboptimally define the distal course and extent of a coronary anomaly.

Computed tomography (CT) scanning

Robust imaging technologies of electron-beam CT (EBCT) and multidetector row CT (MDCT) using intravenous contrast injection have shown excellent definition of coronary arterial anatomy (as is shown in the image below).

Three-dimensional volume rendering from multidetec Three-dimensional volume rendering from multidetector CT imaging of a large right coronary artery aneurysm (arrow). Subtraction of the myocardium in B shows the fistula draining to the coronary sinus and then into the right atrium. (Reproduced from Manghat NE, Morgan-Hughes GJ, Marshall AJ, Roobottom CA: Multidetector row computed tomography: imaging congenital coronary artery anomalies in adults. Heart 2005 Dec; 91(12): 1515-22).

Following a period of approximately 20 seconds of acquisition, very detailed 3-dimensional reconstruction of the origin and course of the coronary distribution can be obtained. Advantages of EBCT and MDCT include greater spatial resolution, with better distal coronary artery and side-branch visualization than MRI.

CT scanning is useful in coronary artery anomalies associated with congenital heart disease.[19] Recently a new classification system for coronary artery anatomy in patients with d-TGA has been proposed based on CT angiography.[20]

Nuclear imaging

In children, radionuclide studies are used to study regions of myocardium at risk for myocardial ischemia and acute or remote myocardial infarction.

Myocardial perfusion imaging with compounds labeled with thallium-201 or technetium-99m permits evaluation both at rest and with exercise. The radiopharmaceutical is taken up by myocardial cells at a certain rate of extraction. Under basal conditions, 88% of thallium is extracted during the first transit. Decreased accumulation of radionuclide indicates underperfusion relative to other areas of myocardium.

Rubidium-82 positron emission tomography (PET) scanning may have use in assessment of myocardial perfusion in children.[21]

Other Tests

Electrocardiography (ECG)

ECG demonstrates findings of myocardial ischemia, injury, and/or infarction. Characteristic electrocardiographic patterns are evident in patients with evolving myocardial infarction and may include changes in T waves, ST segments, and QRS complexes. These serial changes are most evident in the distribution of the myocardium involved and may include reciprocal changes in leads facing away from this region.

Particularly evident are patterns of ischemia that cause T-wave inversion resulting from repolarization changes, muscle cell injury that causes ST segment elevation, and areas of infarction manifested as Q or QR alteration in QRS complexes.

ECG may also be a useful test in patients with coronary anomalies associated with congenital heart disease.[22]

Preparticipation ECG screening is becoming increasingly common for athletes; some countries have mandatory requirements across many sporting activities. Guidelines related to preparticipation screening for cardiovascular abnormalities in competitive athletes have been established.[23, 24, 25, 26, 6, 27, 28, 29, 30, 31]

Exercise stress test

During exercise, the coronary blood flow increases 5-fold to 6-fold. Blood supply and oxygen delivery may be adequate at rest but may be unable to meet increased demands during exercise.

Treadmill or pharmacologic stress protocols may be administered, with immediate postexercise and late redistribution studies performed to delineate regions of myocardium at risk.

Procedures

Cardiac catheterization (as is shown in the image below) may be warranted if noninvasive studies fail to define specific anatomic abnormality.

Selective right coronary arterial injection in an Selective right coronary arterial injection in an 8-month-old female with tetralogy of Fallot malformation. Study demonstrates left anterior descending coronary artery (LAD) arising early from the right coronary artery (RCA) and coursing across the right ventricular outflow tract. Left anterior oblique projection.

Right heart pressures may be elevated as a reflection of left heart compromise. Aortic root angiography may be sufficient to accurately define a specific coronary anomaly, yet selective coronary artery studies may be necessary.

Experience in coronary arteriography is necessary to accurately define and identify significant coronary variations.

Postcatheterization precautions to monitor for include hemorrhage, vascular disruption after balloon dilation, pain, nausea and vomiting, and arterial or venous obstruction from thrombosis or spasm. Complications may include rupture of blood vessel, tachyarrhythmias, bradyarrhythmias, and vascular occlusion. These invasive studies carry a significant risk in critically ill infants, and often the experience of an angiographer who specializes in adults may be helpful.

 

Treatment

Medical Care

An infant with symptoms of coronary artery ischemia or injury requires intensive care management and therapies. Direct initial efforts at reducing myocardial oxygen demands, possibly including oxygen administration, correction of acid-base status, endotracheal intubation, and paralysis to reduce work of breathing.

Additional beta-agonist inotropy may be used in a life-saving circumstance but is likely to result in increased oxygen use and may precipitate malignant ischemic dysrhythmias. For mechanical support, left ventricular assist devices (LVADs) or extracorporeal membrane oxygenation (ECMO) have been used effectively as bridges to surgery.

Phosphodiesterase inhibitors can be used to enhance inotropy and obtain peripheral vasodilation that reduces afterload. In association with anomalous coronary artery arising from the pulmonary artery, milrinone may precipitate a reduction in pulmonary vascular resistance.

Loop diuretics may be used to relieve symptoms of congestive heart failure (CHF).

Beta-adrenergic blockers may be used in selected cases of coronary abnormalities to reduce myocardial oxygen consumption and reduce predisposition to ischemia. A recent study concluded that current data does not support or discourage the use of beta-blockers in children with CHF.[32]

Surgical Care

Surgical management of coronary abnormalities varies and often requires the combined expertise of both adult and congenital cardiac surgical specialists.

In addition to all the varied techniques of coronary arterial bypass, anomalous origin of coronary artery from pulmonary artery may require Takeuchi tunnel repair techniques or the Jatene button relocation technique. Long-term complications are common after the Takeuchi repair and include pulmonary stenosis, baffle leaks, mitral regurgitation, and/or left ventricular dysfunction.[33]

Addressing coronary ostial obstruction or intramural coronary courses often requires unroofing (as is shown in the image below), unique resection, and patching strategies.

Operative repair of anomalous left coronary artery Operative repair of anomalous left coronary artery (LCA) from the right sinus of Valsalva. The slitlike anomalous origin of the left coronary artery from the right aortic sinus of Valsalva is demonstrated, as is the intramural course of the coronary artery. (B) The intramural course of the artery is unroofed, placing the functional ostium in the left sinus. (C) Tacking sutures are used to secure the intima of the new coronary ostium and to reinforce the adjacent commissure of the aortic valve. (Reproduced from Jaquiss RD, Tweddell JS, Litwin SB: Surgical therapy for sudden cardiac death in children. Pediatr Clin North Am 2004 Oct; 51(5): 1389-400).

Although controversy exists regarding the diagnosis and treatment of anomalous aortic origin of a coronary artery, a study of 50 patients who underwent surgical repair demonstrated no operative mortality and good medium-term (median follow-up, 5.7 y) results (47/50 free of cardiac symptoms, and no patient with sudden death).[34]

In cases of coronary fistula, cardiac catheterization with coronary embolization using coils and devices has been an effective therapy in many instances.[35]

Farouk et al published a discussion of operative technique and review of the literature on anomalous left coronary artery arising from the right pulmonary artery.[36]

Consultations

Consultations often are required for optimal management of varied coronary artery anomalies in children. These may include a colleague experienced in the techniques of selective coronary arteriography and intervention in adults, nuclear medicine radiographers knowledgeable in quantification of myocardial injury and recovery potential, and both pediatric and adult cardiovascular surgeons to facilitate optimal surgical repair.

Transfer

Transfer patients to a facility with specialists experienced in the techniques of selective coronary arteriography and intervention, with specialists experienced in nuclear medicine, with radiographers knowledgeable in quantification of myocardial injury and recovery potential, and with both pediatric and adult cardiovascular surgeons to facilitate optimal surgical repair.

Activity

Individualize recommended activity for those patients who have sustained a cardiac injury. Cautiously reintegrate patients into physical education and sports.

Recommendations may be aided by periodic stress assessments. However, even these may not absolutely ensure the prevention of potential catastrophic events.