Abstract
Introduction Atresia of the left main coronary artery (LMCA) refers to a congenital defect in which both the LMCA and its coronary ostium fail to develop, despite the presence of anatomically normal left anterior descending and circumflex branches. This condition is exceedingly uncommon, with fewer than 60 documented instances reported globally over the past 70 years [ 1 ]. In cases of LMCA, the existence of Vieussens’ arterial ring – a connection forming a circular anastomosis between the conus branch of the right coronary artery and the left anterior descending artery (LAD)—provides an alternative pathway for perfusion of the otherwise isolated left coronary circulation. This represents a very rare coronary anomaly. Only 7 case reports describing the combination of Vieussens’ ring and left main atresia are documented in the literature [ 2 ]. Publication History Received: 25 June 2025 Accepted after revision: 21 August 2025 Article published online: 08 September 2025 © 2025. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany