Anatomical characteristics of anomalous left coronary artery from the opposite sinus (left-ACAOS) and its clinical relevance: A serial coronary CT angiography study

BACKGROUND: Anomalous left coronary artery from the opposite sinus (left-ACAOS) is a rare congenital heart disease. While “interarterial course” is considered as the malignant anatomic feature for these patients, a number of patients with left-ACAOS, who don’t follow the above anatomic pattern, were reported with ischemic symptoms. PURPOSE: This study aims to evaluate the anatomic characteristics of left-ACAOS and their clinical relevance. METHODS: The coronary computed tomography angiography (CCTA) data from 44 patients with 46 left-ACAOS vessels were retrospectively included. Patients were divided into 2 groups: those with ischemic symptoms (n = 19) and those without ischemic symptoms (n = 25). Baseline clinical characteristics were recorded and the follow-up was done by telephone. CCTA images were reviewed for anomalous coronary artery, take-off angle and level, ostia morphology and grading, proximal narrowing, anomalous course and atherosclerotic plaques. RESULTS: The prevalence of left-ACAOS was approximately 0.09% among 48, 719 consecutive patients referred for coronary CTA in our institution. Right sinus of Valsalva (RSV) was the most common origin (36/46, 78.26%). Left-ACAOS arising from right coronary artery (RCA) had narrower proximal segment (P = 0.014) and more prone to atherosclerosis (P = 0.040) than left-ACAOS arising from right sinus of Valsalva (RSV). Proximal narrowing severity (P < 0.001) and degree of maximal coronary stenosis (P = 0.034) of the anomalous left artery was higher in patients with ischemic symptoms than those without. Of note, no MACE was recorded during a mean follow-up of 43.4 ± 26.2 months. CONCLUSION: Left-ACAOS arising from RCA seems to be more prone to atherosclerosis than other subtypes. Proximal narrowing was more severe in patients with ischemia symptoms, which may contribute to risk stratification and clinical management.