Transcatheter Management of Coronary Sinus Atrial Septal Defect in L-Transposition of the Great Arteries

Background: Coronary sinus atrial septal defects (CS-ASDs) have seldom been described in patients with congenitally corrected transposition of the great arteries. When present, CS-ASDs typically present similarly to other atrial septal defects with left-to-right shunting and right-sided dilation. Case Summary: We describe the first reported case of hypoxemia because of a CS-ASD in a patient with congenitally corrected transposition of the great arteries, managed percutaneously by deployment of a covered stent and embolization with a vascular plug of a persistent left superior vena cava draining into the coronary sinus. Discussion: Right-to-left shunting and cyanosis related to CS-ASDs is a rare presentation, which in this case was not caused by either pulmonary hypertension or left ventricle to pulmonary artery conduit stenosis but perhaps could be attributed to mild mitral stenosis. Take-Home Message: Transcatheter closure of CS-ASDs as an alternative to surgery can be considered in rare instances and may resolve cyanosis related to right-to-left shunt.