Huge thrombus growing on an aortic prosthetic valve detected in acute coronary syndrome.

A 74-year-old woman with a history of aortic valve replacement (AVR) with a tilting prosthesis at the age of 59 was referred to our hospital with chest pain at rest. Following conservative treatment after admission, the laboratory findings demonstrated acute myocardial infarction. Although bilateral coronary arteries exhibited no significant stenosis and embolism on the emergency coronary angiogram, a huge mobile mass above the prosthetic valve was recognized on the aortography, computed tomography, and trans-esophageal echocardiography. Operative findings demonstrated that the huge mobile thrombus was growing from the sawing ring on the side of minor orifice and almost covered the ostium of the left coronary artery. Emergency re-AVR with 21 mm SJM HP valve was performed. This clinical course suggested that the acute coronary syndrome might be caused by the isolated thrombus on the aortic prosthetic valve without any insufficiency of prosthesis and embolic findings due to the thrombosed valve.