Anomalous origin of the left coronary artery from the pulmonary artery with coronary artery fistula in an adult presenting with cardiomegaly, abnormal electrocardiogram, myocardial perfusion defect and pulmonary hypertension: a case report.

The anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) represents a rare and potentially life-threatening coronary anomaly. The clinical manifestations, progression, and prognosis of ALCAPA are significantly influenced by the degree of collateral circulation. Only 10%-15% of untreated individuals with ALCAPA develop extensive collateral circulation from the right coronary artery, enabling them to survive into adulthood with either no symptoms or various nonspecific symptoms, thereby presenting considerable diagnostic challenges. Furthermore, ALCAPA may occur in isolation or in conjunction with other congenital heart diseases, which can obscure its presence and complicate its management. Herein, we present a distinctive case of an adult patient with ALCAPA and coronary-pulmonary artery fistula, who exhibited facial edema and mild pericardial effusion secondary to severe hypothyroidism, without any cardiac symptoms. Given the patient's cardiomegaly, coronary artery calcification, abnormal electrocardiogram, and hyperlipidemia, coronary angiography was conducted, which incidentally revealed the presence of ALCAPA and the coronary-pulmonary artery fistula. Subsequent right heart catheterization and resting single-photon emission computed tomography myocardial perfusion scintigraphy identified pre-capillary pulmonary hypertension and regional myocardial perfusion defect in the anterior and lateral walls of the left ventricle. This case underscores the considerable difficulty in diagnosing adult ALCAPA and emphasizes the need for a thorough evaluation in patients presenting with atypical cardiac manifestations.