Untreated incomplete ALCAPA in an adult resulting in mitral regurgitation and reduced left ventricular ejection fraction: case report.

Background: Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital malformation, with an incidence ranging from 1 in 300 000 to 1 in 30 000 live births. Incomplete ALCAPA is defined as an abnormal origin of either the left anterior descending coronary artery (LAD) or the circumflex artery from the aorta. It may also present as ALCAPA with duplication of one of these arteries due to an additional branch arising from the aorta. Case summary: The case report presents a man diagnosed with dilated cardiomyopathy at the age of 29. Despite repeated echocardiographic examinations, the diagnosis of incomplete ALCAPA (additional LAD arising from the aorta) as the aetiology of the dilated cardiomyopathy with reduced left ventricular ejection fraction and severe mitral regurgitation was only established at age 57. The patient underwent surgical correction of the ALCAPA and mitral valve repair. Despite optimal surgical intervention, only minimal postoperative improvement in the left ventricular ejection fraction was observed. Discussion: According to guidelines, computed tomography angiography is the most effective diagnostic method for anomalous origin of coronary artery from the pulmonary artery (ACAPA). Due to ACAPA's extreme rarity, standard indications for surgical intervention in incomplete ALCAPA are not established. Surgical correction appears most suitable for symptomatic patients. It should also be considered for asymptomatic patients with ventricular dysfunction or myocardial ischaemia caused by the coronary anomaly.