Description

The anomalous coronary artery arises from the pulmonary artery rather than from its usual origin, the aorta. Most commonly, the anomalous left coronary artery arises from the pulmonary artery in a condition known as ALCAPA or Bland-White-Garland syndrome.

Epidemiology

• The majority of patients present in infancy at approximately 2 months of age when pulmonary vascular resistance falls.
• There are case reports of patients presenting as late as the 4th to 8th decades of life.

Pathophysiology

• In the fetal and neonatal period, pulmonary vascular resistance is increased relative to systemic vascular resistance providing the driving force for antegrade flow from the pulmonary artery through the anomalous coronary artery to supply the ventricle.
• As pulmonary vascular resistance drops, pulmonary arterial pressure drops. When the diastolic blood pressure in the pulmonary artery decreases below myocardial perfusion pressure (or diastolic aortic pressure), pulmonary run-off "steals" blood from the myocardium, resulting in myocardial ischemia. In ALCAPA, ischemia of the anterolateral left ventricular wall occurs leading to left ventricular and mitral valve papillary muscle dysfunction.
• The fact that the ventricle is perfused with desaturated blood plays a less important role than the overall perfusion-related imbalance between myocardial oxygen demand and supply.

Etiology

• Abnormal septation of the conotruncus into the aorta and pulmonary artery
• Persistence of the pulmonary buds and involution of the aortic buds that usually form the coronary arteries
• As-yet-unspecified genetic predisposition

History

• Typically presents with paroxysms of poor feeding, pallor, cough, tachypnea, respiratory distress, and diaphoresis
• Irritability, crying, appearance of being in pain (especially after meals)
• Can be asymptomatic
• Can be symptomatic in infancy and then gradually improve if adequate coronary collateralization develops
• Older children may have exercise intolerance, dyspnea, syncope, chest pain, palpitations.
• Sudden death, especially with exertion

Physical Exam

• Signs of congestive heart failure (CHF) such as cachexia, tachycardia, tachypnea, increased work of breathing, lethargy, diaphoresis
• Signs of low cardiac output such as pallor, diminished peripheral pulses, and perfusion
• Gallop rhythm
• Narrowly split S₂ with a loud P₂ component (if left ventricular heart failure raises pulmonary arterial pressure)
• Murmur of mitral regurgitation or a continuous murmur reminiscent of a coronary arteriovenous fistula
• Diagnosis should be entertained in any infant presenting with cardiomegaly or perplexing cardiorespiratory symptoms.

Differential Diagnosis

• Dilated cardiomyopathy
• Myocarditis
• Coronary artery fistula
• Left ventricular failure from other causes
• Mitral valve regurgitation from other causes
• Respiratory distress from other causes
• Colic

General Measures

The first priority is to safely institute supportive care measures while expeditiously planning for surgical intervention.

Surgery/Other Procedures

• Direct reimplantation of the left coronary artery into the aorta using a button of pulmonary arterial tissue and/or an extension-tube graft of anterior and posterior pulmonary arterial wall tissue sewn into a narrow cylinder to avoid tension, distortion, and stenosis of the coronary artery
• Creation of an aortopulmonary window and tunnel that directs blood from aorta to the left coronary ostium (Takeuchi procedure)
• Ligation of the origin of the left coronary artery and reconstitution with a coronary artery bypass graft; performed with or without the use of cardiopulmonary bypass
• Ligation of the origin of the left coronary artery (to prevent flow runoff into the pulmonary artery or "steal") is rarely ever performed in the current era.

Admission, Inpatient, and Nursing Considerations

• Attention to basic life support measures (airway, breathing, and circulation) and prompt referral to a pediatric cardiac center are indicated immediately on presentation.
• As myocardial ischemia can be worsened with traditional heart failure treatments such as oxygen administration, afterload reduction, and inotropic support, these therapies should be administered in consultation with a pediatric cardiac care center.
• An excess of procedures, interventions, and manipulation is poorly tolerated by this group of critically ill patients.

• Untreated, 90% of those who present in infancy will die before the age of 1 year, usually at 1 to 2 months of age (when pulmonary vascular resistance falls).
• Late results after surgery are excellent in many centers. Hospital mortality in larger selected series is ≤5%, with very little subsequent attrition.
• Mitral regurgitation commonly resolves completely after surgery establishes a patent dual-coronary system, but this may take 6 to 12 months to be fully realized. Follow-up evaluation is warranted, as mitral regurgitation may progress despite surgery and valve repair may be required later.
• Complete normalization of global left ventricular systolic function is common. However, evidence of chronic regional left ventricular function impairment is apparent with echocardiographic myocardial strain evaluation. Cardiac MRI commonly reveals wall motion abnormalities, perfusion deficits, and myocardial fibrosis.
• Residual coronary artery lesions, such as coronary artery stenosis or aneurysms can occur.
• At least moderate pulmonary valve insufficiency typically develops after the Takeuchi procedure.

ICD9

• 746.85 Coronary artery anomaly

ICD10

• Q24.5 Malformation of coronary vessels

SNOMED

• 450301003 Anomalous origin of left coronary artery from pulmonary artery (disorder)