Giant Calcified Right Coronary Artery-to-Right Atrial Fistula Associated with Tricuspid Regurgitation and Thrombocytopenia

Coronary artery fistulas are rare, and large right coronary artery-to-right atrial (RCA-RA) fistulas with systemic complications are even rarer. We report the case of a 74-year-old woman with a giant, calcified RCA-RA fistula accompanied by thrombocytopenia and recurrent gastrointestinal bleeding. Computed tomography revealed a 20-mm calcified aneurysmal fistula. Echocardiography revealed severe tricuspid regurgitation, moderate mitral regurgitation, moderate pulmonary hypertension, and a continuous shunt flow with an estimated pulmonary-to-systemic blood flow ratio of 1.39. A preoperative evaluation revealed a model for endstage liver disease (MELD) score of 9 and MELD-XI of 12.1, thus suggesting that the organ dysfunction was potentially reversible. The patient underwent a successful surgical repair, including saphenous vein grafting to the distal RCA, fistula resection with bovine pericardial patch reconstruction, mitral and tricuspid annuloplasty, and left atrial appendage resection. Postoperatively, the platelet count normalized by day 7, gastrointestinal bleeding resolved, and sinus rhythm was restored. At 6 months, echocardiography showed trivial tricuspid and mitral regurgitation with a preserved biventricular function. This case demonstrates that the curative surgical repair of a large RCA-RA fistula can reverse systemic manifestations, such as thrombocytopenia, by resolving congestive hepatopathy, even in high-risk patients.