Anomalies of the Coronary Sinus

Failure to identify the uncommon anomalies of the coronary sinus can have serious consequences during cardiac surgery or interventions. Formed from the left sinus venosus, it can retain connection with the left cardinal vein, creating a persistent left superior vena cava (PLSVC). Another anomaly, unroofed coronary sinus, occurs because of failure in the formation of the wall between the coronary sinus and left atrium. Unroofed coronary sinus includes a combination of left superior vena cava to left atrium, absent coronary sinus, and atrial septal defect in the location of the coronary sinus orifice. Unroofed coronary sinus may be associated with either a right-to-left or a left-to-right shunt, and several variants exist. Atresia of the coronary sinus is rare and often coexists with PLSVC, which serves to provide a site of drainage of coronary venous blood. These anomalies must be recognized by imaging modalities prior to cardiac intervention.