Is the Left Coronary Artery (LCA) dilated in Anomalous Left Coronary Artery from the Pulmonary Artery (ALCAPA)?

Left Coronary Artery Dilation in ALCAPA

Yes, the Left Coronary Artery (LCA) is typically dilated in Anomalous Left Coronary Artery from the Pulmonary Artery (ALCAPA) syndrome. This dilation occurs primarily due to the development of significant collaterals from the right coronary artery (RCA) to the LCA.

Pathophysiology of LCA Dilation in ALCAPA

• In ALCAPA, the LCA originates abnormally from the pulmonary artery instead of the aorta, resulting in retrograde flow and lower oxygen content in the coronary circulation 1
• The right coronary artery (RCA) becomes dilated as it develops extensive collaterals to supply the left coronary system, and this collateral network leads to dilation of the LCA as well 1
• Adult survivors with ALCAPA typically have significant collateral development from the RCA to the LCA, which contributes to the dilation of both vessels 2

Clinical Significance of Coronary Dilation

• Despite collateral development and LCA dilation, chronic subendocardial ischemia still occurs in most cases, which can lead to myocardial dysfunction 1
• The dilated coronary arteries in ALCAPA are a key diagnostic feature that can be identified on imaging studies such as CT angiography or cardiac catheterization 2
• Case reports have documented dilated RCA extending to the left ventricle with anomalous left main originating from the pulmonary artery 1

Diagnostic Imaging for ALCAPA

• Echocardiography may identify the dilated coronary arteries in children and young adults but has limitations in older adults 2
• CT or magnetic resonance angiography is recommended as the initial screening method in centers with expertise in such imaging 2
• Coronary angiography remains valuable for delineating arterial course, branches, and assessing for atherosclerosis 2
• Coronary CTA has become the "gold standard" for assessment of anomalous coronary origin and course in adults 2

Management Implications

• The ACC/AHA guidelines recommend reconstruction of a dual coronary artery supply in patients with ALCAPA 2
• Surgery should be performed by surgeons with training and expertise in congenital heart disease at centers with expertise in managing anomalous coronary artery origins 2
• Two main surgical approaches are used:
  • Direct reimplantation/translocation of the LCA to the aorta 3
  • Takeuchi procedure (creating an intrapulmonary tunnel) when the LCA arises far from the aorta 3

Long-term Follow-up

• For adult survivors of ALCAPA repair, clinical evaluation with echocardiography and noninvasive stress testing is indicated every 3 to 5 years 2
• Even after successful repair, residual coronary abnormalities may persist, including proximal, midvessel, and distal coronary artery obstructions 2
• Patients may have residual myocardial fibrosis from preoperative ischemia, requiring ongoing surveillance 2

Clinical Pearls and Pitfalls

• ALCAPA should be considered in young adults with dilated cardiomyopathy and mitral regurgitation 1
• Common presentations include acute myocardial infarction, angina, dyspnea on exertion, and sudden cardiac death 1
• The risk of sudden cardiac death tends to decrease with age of diagnosis 1
• Even in patients with normal left ventricular function, significant myocardial damage may remain long after surgery, necessitating lifelong follow-up 4