Spontaneous thrombosis of an unroofed coronary sinus: case report.

Background: Unroofed coronary sinus (UCS) is a rare congenital anomaly and is usually found incidentally. While coronary sinus thrombosis (CST) can occur following instrumentation of the coronary sinus, spontaneous CST is a rare occurrence and only a few cases have been reported to date. The presence of both rare entities concurrently has not been reported previously. Case summary: A 57-year-old man presented with rectal bleeding and was in hypovolaemic shock. On computed tomography (CT), he was found to have ischaemic colitis as well as an incidental finding of a Type IV UCS with CST. He was initially managed with intravenous heparin infusion but developed life-threatening upper gastrointestinal bleeding, requiring endoscopic clipping of a gastric ulcer. The patient was recommenced on intravenous heparin and later transitioned to oral anticoagulant without further events. Discussion: In UCS, the coronary sinus communicates with the left atrium. The majority of patients are asymptomatic, and the anomaly usually goes undetected. In this patient, UCS was found incidentally with concurrent spontaneous CST. The ischaemic colitis was likely due to cardioembolism from the CST. In the absence of evidence-based practice, we described our cautious approach to anticoagulation in this critically unwell patient. Furthermore, advances in cardiac intervention have seen an increasing need to instrument the coronary sinus and an increased awareness of coronary sinus anomalies is important. Cardiac CT provides an excellent imaging tool for assessing the coronary sinus anatomy (as demonstrated in this case) and can be helpful in pre-procedural planning.