Coronary Orificial Atresia Congenital atresia of the main stem of the left coronary artery is very rare, with no more than solitary cases reported thus far In congenital orificial atresia, there is no orifice for the main stem from the aortic root Instead, the left anterior descending and left circumflex coronary arteries remain in their anatomically correct position but end blindly and receive blood flow solely retrograde from the RCA, usually via collateral vessels.58 Typically, these collateral vessels are inadequate to perfuse the left heart, and patients are almost always symptomatic This lesion is differentiated from a single coronary artery by the direction of blood flow in the left coronary arterial system When there is a single RCA giving rise to all three major coronary arteries, flow is antegrade and most patients are asymptomatic Although congenital orifical atresia usually occurs in isolation, associations have been noted with supravalvar aortic stenosis, ventricular septal defect with pulmonic stenosis, right coronary orificial stenosis, and patency of the arterial duct with aortic insufficiency Pathophysiology The pathophysiology of congenital orificial atresia is that of collateral perfusion of the left coronary arterial system As the collateral vessels are typically smaller than the left-sided coronary arteries, there is typically not enough blood flow through these vessels to meet myocardial oxygen demand This leads to LV myocardial ischemia and the potential for sudden death Clinical Presentation Clinically, patients can present at a wide range of ages from infancy into adulthood Regardless of the age of presentation, patients are nearly always symptomatic The age at presentation likely has to do with the extent and adequacy of the collateral circulation Infants and young children present with signs of heart failure and ischemia, similar to ALCAPT or dilated cardiomyopathy Specifically, they will have feeding difficulty, failure to thrive, and dyspnea A holosystolic murmur from mitral regurgitation due to infarcted papillary muscles may be present The younger patients are also more likely to have associated congenital heart disease because these lesions may increase myocardial demand leading to an earlier presentation Older children, adolescents, and adults may present with syncope, dyspnea, angina, and ventricular arrhythmias Sudden death can be the first presentation at all ages Diagnostic Testing In infants and children, the chest x-ray may show cardiomegaly with pulmonary congestion due to heart failure In adolescents and adults, the chest x-ray may be normal A 12-lead ECG may show evidence of ischemia, typically anterolateral Q waves, lateral T wave inversion, right bundle branch block, or ventricular tachycardia A transthoracic echocardiogram is likely to show a dilated left ventricle with poor function and mitral regurgitation Similar to ALCAPT, the location of the atretic orifice should be clearly evaluated Doppler color flow may show retrograde flow from the RCA to the left coronary system without filling in the pulmonary trunk Notably, an orifice for the main stem of the left coronary artery will not be clearly demonstrated To differentiate from ALCAPT, the left circumflex coronary artery should be clearly evaluated In ALCAPT, retrograde flow will be demonstrated in the left circumflex coronary artery In left coronary ostial atresia, antegrade flow will be demonstrated in the left circumflex coronary artery.23 Because coronary arterial origins can be difficult to demonstrate by echocardiography alone, cardiac catheterization with coronary angiography is the gold standard of diagnosis (Video 46.6) If there is a question of the correct diagnosis, selective angiography should be performed in the RCA if this is possible Surgical Technique Due to the high risk of sudden death with congenital orificial atresia, surgery should be performed as soon as possible after diagnosis The majority of cases have been treated by coronary artery bypass grafting Some reports have described the use of autologous pericardial patch, saphenous vein onlay patch, or pulmonary homograft patch to attain surgical revascularization by creating a new orifice.59–61 Outcomes Because congenital orificial atresia is primarily limited to case reports in the literature, long-term outcome data are not available in this population Shortterm postoperative mortality appears related to the extent of myocardial injury at the time of diagnosis and operation If the atresia is noted early and significant collateralization is present, short-term results are encouraging after surgical revascularization