Myocardial Infarction in Childhood 

Updated: May 23, 2014
Author: Louis I Bezold, MD; Chief Editor: Stuart Berger, MD 

Overview

Background

Acute myocardial infarction (AMI) is rare in childhood and adolescence. Although adults acquire coronary artery disease (CAD) from lifelong deposition of atheroma and plaque, which causes coronary artery spasm and thrombosis, children usually have either an acute inflammatory condition of the coronary arteries or an anomalous origin of the left coronary artery (LCA). Intrauterine myocardial infarction (MI) also does occur, often in association with coronary artery stenosis.[1]

Pathophysiology and Etiology

Whatever the etiology, the final common pathway of AMI includes myocardial ischemia (resulting in hypoxia), release of inflammatory cytokines, and cell death. The terminal event is often a cardiac arrhythmia, either ventricular tachycardia deteriorating to ventricular fibrillation or extreme bradycardic arrest. The onset of the terminal event is heralded by a loss of peripheral circulation and consciousness and by cardiovascular collapse and cardiac arrest. Two leading causes of AMI in children are anomalous origin of the LCA from the pulmonary artery (ALCAPA) and Kawasaki disease.

ALCAPA

Infants with ALCAPA develop irritability with dyspnea, tachycardia, diaphoresis, and vomiting while feeding. Irritability is secondary to anginal pain caused by a coronary artery steal phenomenon to the anomalous origin of the LCA. The flow in this vessel, which has its distribution over the left ventricular myocardium, is retrograde to the main pulmonary artery.

The diagnosis of ALCAPA is suspected in irritable anxious infants presenting with pain while feeding (a modified stress test). Electrocardiography (ECG) demonstrates classic findings of deep Q waves, peaked T waves, or ST segment changes consistent with ischemia, injury, or infarction. Confirmation of the anomaly may be obtained by means of high-quality 2-dimensional and Doppler echocardiography or cardiac catheterization with angiography. A high degree of suspicion must predominate to make this diagnosis.

Kawasaki disease

Kawasaki disease is an acquired disease of unknown etiology, and it can affect all cardiac tissues (pericardium, endocardium, myocardium, valves, and conductive tissue). The pathogenetic mechanism is attributable to a high degree of immune activation. Since the introduction of intravenous (IV) gamma globulin as part of standard therapy for Kawasaki disease, the incidence of AMI due to Kawasaki disease has decreased.[2]

Coronary artery involvement occurs in 15-25% of children with Kawasaki disease within 1-3 weeks of onset. In patients with untreated Kawasaki disease or with residual coronary aneurysms, sudden death has resulted from AMI caused by ruptured coronary artery aneurysms or thromboses. Detrimental changes in arterial wall hemodynamics are present and persist after acute Kawasaki disease, and these changes may predispose to long-term cardiovascular events.

See Kawasaki Disease: Do You Know the Signs?, a Critical Images slideshow, to help identify the specific criteria for diagnosis.

Other conditions

Other, often rarer, conditions that predispose children to AMI have been described, including dextro-transposition of the great arteries (D-TGA), tetralogy of Fallot, and pulmonary atresia.

D-TGA

For patients undergoing the Jatene arterial switch procedure, the presence of an intramural coronary artery course in patients with D-TGA may prohibit arterial repair. Hypothetically, manipulation of the intramural coronary artery may cause damage and resultant inflammation, kinking, thrombosis, and myocardial ischemia or infarction (see Transposition of the Great Arteries).

Tetralogy of Fallot

Surgical repair of pulmonary outflow obstruction often involves patching the right ventricular outflow tract and resecting the obstructing right ventricular muscle. An estimated 2-9% of patients with tetralogy of Fallot have coronary arterial anomalies, which may affect the timing of or approach to surgical repair.

The most common anomaly (4% of patients) is the origin of the left anterior descending (LAD) coronary artery from the right coronary artery (RCA), which then courses across the pulmonary outflow tract. Inadvertent transection of this vessel yields disastrous consequences. Frequently, the conus branch of the RCA is large and supplies a significant portion of the 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 means of noninvasive or invasive studies (see Tetralogy of Fallot with Pulmonary Atresia).

Pulmonary atresia with intact ventricular septum

Primitive embryonic sinusoidal connections to coronary vasculature may demonstrate severe intimal thickening, occlusion, or interruption. The RCA is most commonly affected, followed by the LAD and, less frequently, the distal extent of the circumflex coronary artery. In most patients, endocardial fibroelastosis, myocardial fibrosis, and AMI are observed (see Pulmonary Atresia with Intact Ventricular Septum).

Additional relatively uncommon predisposing conditions are as follows:

  • Coronary artery ostial stenosis or coronary artery kinking – These may present after arterial switch repair of D-TGA in the neonatal period or may develop years later, possibly related to aortic root dilation; they may also occur after a Ross procedure for aortic valve disease

  • Other abnormalities of coronary structure or course – Left main coronary artery atresia is a rare anomaly that can masquerade as dilated cardiomyopathy; coronary ostial stenoses can be seen in patients with Williams syndrome, most commonly accompanying supravalvular aortic stenosis but on rare occasions in isolation[3] ; infarction can present in utero in these cases[1] Acute MI due to fibromuscular dysplasia in a 12-year-old boy has recently been reported.[4]

  • Sudden death – Sudden death due to an aberrantly coursing left main coronary artery with its origin at the right sinus of Valsalva may present in athletes who are exercising.

  • Coronary insufficiency – This may develop in patients with Marfan syndrome, Takayasu arteritis, or cystic medial necrosis with aortic root dilatation, aneurysm formation, and dissection into the coronary artery

  • Traumatic MI – Although traumatic MI is very rare, it can occur in patients of any age; however, it is more likely to occur in ambulatory and adolescent patients

  • Atherosclerosis – Accelerated coronary artery atherosclerosis is known to occur in orthotopic cardiac transplant recipients on immunosuppressive therapy

  • Familial homozygous hypercholesterolemia

  • Cocaine and other drug intoxication - Drugs have been associated with MI. K2 (a designer drug with synthetic cannabinoid effects) has reportedly been associated with MI in an adolescent,[5] as has the combination of ethanol and Adderall (amphetamine/dextroamphetamine).[6]

  • Accelerated coronary atherosclerosis due to juvenile diabetic dyslipidemia or nephrotic syndrome

  • Accelerated coronary vascular disease associated with chronic kidney disease and renal failure[7]

  • Accelerated atherogenesis after treatment for childhood cancer

  • Inflammatory conditions such as viral and eosinophilic myocarditis[8] and systemic lupus erythematosus (SLE) - Dyslipidemia frequently occurs in children with SLE and is often underrecognized and undertreated[9]

  • Sickle cell disease

  • Prothrombotic defects (eg, protein C deficiency and prothrombin gene mutations), especially in conjunction with other coronary anomalies[10]

  • Coronary artery spasm in adolescents

  • Complications of dilated or ischemic cardiomyopathy

  • Neonatal MI has been reported sporadically. Multiple possible etiologies have been suggested, including intrauterine myocarditis, adverse effects of maternal oxytocin administration, thromboembolism from umbilical catheters or renal vein thrombosis, coronary artery steal in association with septal hypertrophy in an infant of a diabetic mother, and antithrombin III deficiency.[11, 12]

Epidemiology

United States

According to the Centers for Disease Control and Prevention (CDC), annual mortality from all causes in the US pediatric population ranges from 22 deaths per 100,000 population in children aged 5-14 years to 756 deaths per 100,000 population in infants younger than 1 year. (By way of comparison, annual all-cause mortality is 90 deaths per 100,000 in persons aged 15-24 years and 2,538 deaths per 100,000 in individuals aged 65-74 years.[13] )

The CDC also reports that mortality from AMI is 0.2 deaths per 100,000 population in persons aged 15-24 years and fewer than 0.2 deaths per 100,000 in infants younger than 1 year. (In comparison, AMI mortality is 1.4 deaths per 100,000 population in persons aged 25-34 years and 262 deaths per 100,000 population in individuals aged 65-74 years.[13] )

One study used Nationwide Inpatient Sample (NIS) data from 1998-2001 to determine the incidence and outcomes of adolescent AMI and found an incidence of 157 cases per year, or 6.6 events per 1 million patient-years.[14] Within the subset of adolescents with AMI, the incidence was higher in individuals aged 16-18 years than in individuals aged 13-15 years.

Age- and sex-related demographics

The etiology of MI determines the age of incidence.

ALCAPA may occur as unexplained sudden death in a neonate. Coronary artery ostial stenosis may occur after repair of D-TGA in the neonatal period. In childhood, infarction may occur years after arterial switch due to kinking of the coronary arteries, possibly in association with aortic root dilation. Thrombotic coronary artery occlusion from Kawasaki disease may occur in early childhood.

Sudden death from an aberrantly coursing left main coronary artery with its origin at the right sinus of Valsalva may occur in athletes who are exercising. Coronary insufficiency may develop in patients with Marfan syndrome, Takayasu arteritis, or cystic medial necrosis with aortic root dilatation, aneurysm formation, and dissection into the coronary artery. Though very rare, traumatic MI can occur at any age; it is more likely to occur in ambulatory patients.

Accelerated atherosclerosis is known to occur in orthotopic cardiac transplant recipients on immunosuppressive therapy and can occur in early adolescence. Coronary artery spasm as a cause of acute typical chest pain with associated cardiac enzyme elevation has been increasingly recognized in adolescents with otherwise normal coronary arteries.[15] The incidence of substance abuse and smoking are higher in adolescents with AMI than in adolescents admitted to the hospital for other conditions.[14]

One study from the NIS suggests a significant male preponderance in adolescent AMI (80%).[14]

Prognosis

AMI affects a small subset of children at risk for sudden cardiac death (defined as any natural death from cardiac causes that occurs from minutes to 24 hours after the onset of symptoms[16] ). Early mortality can be high, depending on the cause, the speed of diagnosis, and the availability of therapeutic interventions.

In patients with Kawasaki disease, the highest risk for coronary artery events is in patients with residual giant aneurysms, particularly if both coronary artery systems are involved. A recent study looking at outcomes in 245 patients with giant aneurysms over a median of 20 years after diagnosis of Kawasaki disease reported the incidence of death was 6%, acute MI 23%, and coronary artery bypass grafts 37%. Most myocardial infarctions occurred within 2 years of diagnosis.[17]

Unlike adults with MI secondary to ischemic and atherogenic disease, children with MI who survive are less likely to have significant prolonged illness or disability. Some data suggest that the hospital survival for AMI in adolescents is excellent (mortality, 0.8%).[14]

Early diagnosis by means of echocardiography with color-flow mapping and the development of improved surgical techniques (eg, myocardial preservation) have dramatically improved the prognosis of MI in childhood.

Patient Education

All patients should undergo formal exercise stress testing at an appropriate age to facilitate the development of an appropriate exercise program. Long-term physical restrictions, including restrictions of participation in competitive sports, depend on whether myocardial ischemia is evident at rest or during exercise. No dietary restrictions are necessary after successful surgical revascularization with subsequent clinical improvement.

For patient education resources, see the Heart Center and the Cholesterol Center, as well as Chest Pain, Coronary Heart Disease, Heart Attack, and Tetralogy of Fallot.

 

Presentation

History

Patients experiencing myocardial infarction (MI) in whom sudden death does not occur may present with a prodrome that can include any of the following features:

  • Chest pain (angina)

  • Palpitation

  • Dyspnea

  • Evidence of poor cardiac output

  • Weakness

  • Dizziness

  • Mental confusion

  • Irritability

  • Orthostasis

  • Presyncope

  • Syncope

Physical Examination

Examination findings vary, depending on the degree of disability and the duration of ischemia, and may include the following:

  • Altered level of consciousness – Lethargy, unconsciousness, irritability

  • Pulse abnormalities – Tachycardia, bradycardia, dysrhythmia

  • Respiratory embarrassment – Apnea, bradypnea, tachypnea, hyperpnea, nasal flaring, grunting, head bobbing, retractions (supraclavicular, intercostal, or subcostal), paradoxical respirations, rales, rubs, rhonchi, consolidation

  • Cardiac examination abnormalities – Hyperdynamic precordium, broad cardiac impulse, displaced apical beat, S3, S4, holosystolic murmur at the apex (mitral insufficiency), holosystolic murmur at the left lower sternal border (tricuspid insufficiency), loud pulmonic closure sound (P2, pulmonary hypertension), diastolic murmur of aortic/pulmonary insufficiency, diastolic rumble of increased tricuspid/mitral flow

  • Hypotension and signs of low cardiac output – Cool skin, prolonged capillary refill time (CRFT), diaphoresis, poor turgor, peripheral cyanosis

  • Signs of cor pulmonale (right heart failure) – Jugular vein distention, hepatosplenomegaly, hepatojugular reflux, ascites, peripheral edema

 

DDx

Differential Diagnoses

 

Workup

Laboratory Studies

A number of laboratory studies are indicated in pediatric patients with myocardial infarction (MI).

Testing of cardiac enzymes is the standard for identification of myocardial cell death. The following levels are measured:

  • Aspartate transaminase (AST)

  • Lactate dehydrogenase (LDH) and isoenzymes

  • Creatine kinase (CK)

  • CK-MB isoforms

  • Troponin I and troponin T

Levels of acute-phase reactants are elevated in the early stages of Kawasaki disease. Studies of the following are indicated:

  • White blood cell (WBC) count

  • C-reactive protein (CRP)

  • Erythrocyte sedimentation rate (ESR)

  • Thrombocytosis

  • Alpha1 -antitrypsin (A1AT)

Evaluation for heritable forms of thrombophilia (eg, prothrombin G20210 and C677T MTHFR gene mutations) and protein C deficiencies should be considered in young patients with myocardial ischemia.[10]

Radiography

Chest radiography is indicated to reveal cardiomegaly, with or without pulmonary venous congestion.

Angiographic evaluation of the coronary artery system is indicated on an urgent basis but should be performed with caution because of the inherent instability of the diseased myocardium.

Definitive diagnosis of an anomalous left coronary artery (LCA) from the pulmonary artery is made. Aortography demonstrates an enlarged right coronary artery (RCA) system with collateralization to the LCA and reflux of contrast into the pulmonary arterial system (ie, anomalous origin of the LCA from the pulmonary artery [ALCAPA]). Patients with Kawasaki disease frequently have coronary aneurysm, ectasia, or both.

Echocardiography

Two-dimensional echocardiography may be used to identify the following:

  • The abnormal origin of the LCA from the main pulmonary artery

  • Chamber enlargement

  • Systolic and diastolic dysfunction

  • Coronary artery ectasia or aneurysm

  • A flail mitral valve leaflet and ruptured papillary muscle

  • Segmental wall motion abnormality

  • Mural or intraventricular thrombi

In experienced hands, color-flow Doppler mapping can have the following uses:

  • Diagnosing ALCAPA by demonstrating retrograde flow from the anomalous LCA into the pulmonary trunk

  • Demonstrating the direction of coronary artery flow

  • Quantifying mitral insufficiency

  • Quantifying pulmonary hypertension, in conjunction with spectral Doppler

Tissue Doppler imaging (TDI) is an echocardiographic technique that can noninvasively evaluate myocardial contraction and relaxation. Data suggest that TDI may have a role in early detection of graft failure due to coronary vasculopathy in orthotopic transplant recipients.[18]

CT and MRI

Multislice computed tomography (CT) angiography has been shown to be useful in identifying coronary ostial or arterial stenoses in pediatric patients after an arterial switch operation for dextro-transposition of the great arteries (D-TGA).[19]

Magnetic resonance imaging (MRI) can reveal coronary origins, anatomy, and abnormalities, as well as infarction, in patients with Kawasaki disease.[20, 21, 22] Cardiac MRI has been used to determine myocardial viability and prognosis in a case of MI in utero.[23] Cardiac MRI has also been very useful in distinguishing between MI and myocarditis in pediatric patients with chest pain and elevated troponin.[24]

Electrocardiography

Classic electrocardiographic (ECG) findings for diagnosing ischemia or infarction in adults have been described as follows:

  • Deep Q waves in a completed transmural infarct over the involved areas

  • Peaked T waves hyperacutely

  • ST elevation in the acute phase

  • ST depression when ischemia is present or in the latter stages of acute injury

  • Various dysrhythmias and ectopy secondary to ischemia and irritable myocardium or conductive tissue (see the image below)

    Electrocardiogram in an infant with anomalous orig Electrocardiogram in an infant with anomalous origin of the left coronary artery from the pulmonary artery, demonstrating pathologic q waves in leads I and aVL and diffuse ST-T wave changes consistent with an anterolateral infarction.

An anterolateral infarct is demonstrated with abnormal deep (> 3 mm) and wide (> 30 ms) Q waves in leads I, aVL, V5, and V6, with absent Q waves in leads II, III, and aVF. The QRS axis is typically normal, though a left superior axis is observed in some patients.

ST-segment changes diagnostic of transmural infarction in adults may be seen in pediatric patients in the absence of coronary occlusion.[25] Additional criteria for diagnosing pediatric ischemia have been described, as follows[26] :

  • Wide Q waves (>35 ms) with or without Q-wave notching

  • ST-segment elevation (>2 mm)

  • Prolonged QTc (>440 ms) with accompanying Q-wave abnormalities

Exercise myocardial perfusion stress testing has been shown to be safe and useful for assessment of myocardial perfusion and for risk stratification in children with Kawasaki disease.[27]

Other Studies

Myocardial perfusion imaging may be useful in evaluating myocardial ischemia and infarction in various disease states.[28]

Hemodynamic (oximetric) measurements may demonstrate the following:

  • Decreased systemic venous oxygen content is consistent with low cardiac output

  • A small left-to-right shunt may be demonstrated by oximetry in the main pulmonary artery if ALCAPA is the diagnosis

  • Elevated left atrial pressures are secondary to reduced left ventricular compliance, significant mitral valve insufficiency, or both

 

Treatment

Approach Considerations

Medical care for a disease or condition that predisposes children to acute myocardial infarction (AMI) is discussed more fully elsewhere (see Anomalous Left Coronary Artery from the Pulmonary Artery and Kawasaki Disease).

The primary treatment in patients with anomalous left coronary artery (LCA) from the pulmonary artery (ALCAPA) is surgical. Surgical revascularization may also be necessary in patients with Kawasaki disease who develop significant coronary stenoses or occlusion. Percutaneous transluminal coronary angioplasty (PTCA) for proximal coronary stenoses after an arterial switch procedure for dextro-transposition of the great arteries (D-TGA) has been reported.

The severity of myocardial infarction (MI) symptoms at presentation determines whether the patient is admitted to an intensive care unit (ICU) for aggressive medical management of congestive heart failure (CHF) before surgical revascularization.

Short-term use of oral digoxin, diuretics, and angiotensin-converting enzyme (ACE) inhibitors is common after surgical revascularization. Coronary spasm is generally treated with nitrates or calcium channel blockade.

Initial Supportive Measures

Intensive care and acute management of the infant with symptoms of coronary artery ischemia or injury are initially directed at reducing myocardial oxygen demands while administering oxygen, fluids, or blood products, providing endotracheal intubation, and correcting acid-base status and paralysis to reduce the work of breathing.

Treatment of CHF includes careful administration of diuretics, afterload reduction medications, and inotropic drugs. Spontaneous resolution of CHF symptoms is rare. Surgical revascularization is usually necessary in the event of AMI.

Aggressive afterload reduction may be deleterious in patients with ALCAPA. Right coronary artery (RCA) perfusion may be reduced during aggressive afterload reduction, leading to decreased left coronary blood flow.

Conversely, inotropic support may increase myocardial oxygen consumption significantly, which, in the presence of reduced myocardial blood flow, may worsen ischemia.

Surgical Revascularization

Once the patient is stabilized, surgical revascularization is performed to create a patent coronary arterial distribution (see Anomalous Coronary Artery from the Pulmonary Artery: Surgical Perspective).

Oral administration of digitalis, diuretics, and afterload-reducing medications improves cardiac output and reduces preoperative symptoms in patients with CHF. These techniques are frequently used until left ventricular systolic and diastolic functions improve and mitral insufficiency stabilizes.

Cardiac dysrhythmia secondary to preoperative myocardial ischemia or MI is likely. Monitor continuously in the immediate postoperative period.

In a review of NIS data, only 2% of adolescents with AMI underwent coronary artery bypass grafting (CABG), compared with 12-24% of adults with AMI. The higher incidence of subendocardial AMI and coronary vasospasm (possibly related to substance abuse) in adolescents may at least partially account for this difference.[14]

Successful PTCA for proximal coronary stenoses after an arterial switch procedure has been reported in a small number of patients, with apparently excellent results 3-5 years later.[29, 30] Postcatheterization effects that call for precautions include hemorrhage, vascular disruption after balloon dilation, pain, nausea and vomiting, and arterial or venous obstruction from thrombosis or spasm. Possible complications include blood vessel rupture, tachyarrhythmia, bradyarrhythmia, and vascular occlusion.

NIS data suggest that the use of cardiac catheterization and percutaneous coronary interventions (PCIs) may be less in adolescents with AMI (29%) than in adults with AMI (40-50%). Again, this may be due to a higher incidence of coronary vasospasm and subendocardial AMI in adolescents.[14] A recent study on long-term follow-up in Kawasaki disease patients with giant aneurysms reported a 30-year survival of 49% in patients who had an AMI, compared with a 25-year survival of 95% in patients who had undergone coronary bypass grafting, highlighting the importance of consideration for early revascularization in these patients.[17]

Postoperative care

After surgical revascularization, postoperative care includes the use of inotropes, diuretics, and afterload reduction medication to improve cardiac output and eliminate the preoperative symptoms of CHF. Initial postoperative treatment is usually provided in a pediatric ICU until the patient is extubated and no longer requires intravenous (IV) inotropes or antiarrhythmics.

Monitor patients continuously during the immediate postoperative period because, cardiac dysrhythmia secondary to preoperative myocardial ischemia or MI, though unusual, is a risk that should be taken into account.

Complications

Complications are rare. Whether future valve surgery will be needed depends on the occurrence of hemodynamic complications (eg, residual mitral valve insufficiency precipitated by permanent damage of the mitral valve architecture) after surgical treatment.

Late complications related to coronary artery insufficiency are more likely to occur if revascularization was accomplished via any of the following techniques:

  • Surgical ligation

  • Bypass grafting (the grafts may become occluded or stenotic)

  • Intrapulmonary tunneling, which may cause supravalvular pulmonary stenosis or, less commonly, obstruction of the surgically created aortopulmonary window

Although generally unlikely, inadequate growth of the coronary anastomosis may ensue if surgical reimplantation of the LCA is performed. This complication is similar to the rare reports of late coronary artery problems after an arterial switch procedure for D-TGA, which also requires direct coronary transfer and reimplantation.

Diet and Activity

In general, no specific dietary restrictions are necessary. If failure to thrive was noted preoperatively, patients may require increased caloric density postoperatively. Patients with residual CHF may require salt or fluid restriction.

Activity restrictions are directly related to the severity of the left ventricular dysfunction and postoperative mitral valve insufficiency. In patients who are able to participate in exercise or competitive sports or who have residual postoperative hemodynamic problems, consider recommending avoidance of significant isometric activities. Exercise stress testing (eg, with electrocardiography or echocardiography) is advised for assessment of myocardial response to exercise, preparticipation screening, and ongoing monitoring of conditioning effect.

Prevention

Long-term antiplatelet therapy with aspirin may be needed in patients with conditions predisposing to coronary thrombosis, such as Kawasaki disease with significant aneurysm formation.[31] In patients with giant aneurysms, additional anticoagulation with dipyridamole or warfarin may be recommended. A small retrospective study suggested that combination therapy with warfarin and aspirin was associated with a decreased risk of MI in patients with giant aneurysms due to Kawasaki disease.[32]

Consultations

Consultation with an adult interventional cardiologist is indicated because of the wealth of information he or she can provide have regarding proper imaging planes and anatomic variations of the coronary arteries.

A nuclear medicine radiologist or cardiologist may help quantify approximate myocardial injury and recovery potential. Pediatric and adult cardiovascular surgeons may collaborate to effect optimal surgical repair.

Long-Term Monitoring

The clinical status of the patient in relation to residual CHF symptoms determines the frequency of postoperative outpatient follow-up visits.

Most patients do not require frequent cardiac evaluations after surgical revascularization once ventricular function and mitral valve insufficiency have dramatically improved.

For patients with Kawasaki disease, long-term follow-up is recommended, even in cases without evidence of obvious coronary dilatation or aneurysms. Dipyridamole stress scintigraphy may be useful for long-term follow-up and risk stratification in patients with Kawasaki disease.[33] The progression of stenosis in patients with aneurysms impacts prognosis. Dobutamine stress echocardiography may also be useful in providing independent prognostic data over time, as demonstrated in a cohort of 58 patients with coronary artery lesions following Kawasaki disease followed over 15 years.[34]

Patients on coronary vasodilators for coronary artery spasm require long-term follow-up.[15]

 

Medication

Medication Summary

Medications used in the management of myocardial infarction (MI) in childhood include inotropic agents, antiplatelet agents, and afterload-reducing agents.

Inotropic agents

Class Summary

Inotropes are used to enhance cardiac contractility as an adjunct to treating congestive heart failure (CHF).

Digoxin (Lanoxin)

Digoxin is a cardiac glycoside with direct inotropic effects and indirect effects on the cardiovascular system. It acts directly on cardiac muscle, increasing myocardial systolic contractions. Its indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.

Antiplatelet Agents, Hematologic

Class Summary

Antiplatelet agents are used for reduction of platelet adhesiveness in thrombotic disease and as anti-inflammatory agents for immune-mediated or noninfectious inflammatory conditions.

Aspirin (Anacin, Ascriptin, Bayer Genuine Aspirin)

Aspirin inhibits prostaglandin synthesis, preventing formation of platelet-aggregating thromboxane A2. It may be used in low doses to inhibit platelet aggregation and improve complications of venous stasis and thrombosis.

ACE Inhibitors

Class Summary

Afterload-reducing agents are used for systemic afterload reduction after MI with depressed left ventricular function.

Captopril

Captopril prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion. It is rapidly absorbed, but bioavailability is significantly reduced with food intake. Captopril achieves peak concentration in 1 hour and has a short half-life. It is cleared by the kidney; impaired renal function necessitates dosage reduction.

Captopril is absorbed well when administered orally. It should be given at least 1 hour before meals. If it is added to water, it should be used within 15 minutes. Captopril can be started at a low dose and titrated upward as needed and tolerated.

Enalapril (Vasotec)

Enalapril prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in increased levels of plasma renin and a reduction in aldosterone secretion. It helps control blood pressure (BP) and proteinuria. It decreases the pulmonary-to-systemic flow ratio in the catheterization laboratory and increases systemic blood flow in patients with relatively low pulmonary vascular resistance.

Enalapril has a favorable clinical effect when administered over a long period. It helps prevent potassium loss in distal tubules. The body conserves potassium; thus, less oral potassium supplementation is needed.

Lisinopril (Prinivil, Zestril)

Lisinopril prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in increased levels of plasma renin and a reduction in aldosterone secretion.

Benazepril (Lotensin)

Benazepril prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in increased levels of plasma renin and a reduction in aldosterone secretion.

When pediatric patients are unable to swallow tablets or the calculated dose does not correspond with tablet strength, an extemporaneous suspension can be compounded. Combine 300 mg (15 tablets of 20-mg strength) in 75 mL of Ora-Plus suspending vehicle, and shake well for at least 2 minutes. Let the tablets sit and dissolve for at least 1 hour, then shake again for 1 minute. Add 75 mL of Ora-Sweet. The final concentration is 2 mg/mL, with a total volume of 150 mL. The expiration time is 30 days with refrigeration.

Fosinopril

Fosinopril is a competitive ACE inhibitor. It prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in increased levels of plasma renin and a reduction in aldosterone secretion. It decreases intraglomerular pressure and glomerular protein filtration by decreasing efferent arteriolar constriction.

Quinapril (Accupril)

Quinapril is a competitive ACE inhibitor. It reduces angiotensin II levels, decreasing aldosterone secretion.