A 76 year old woman was referred to our cardiology department for percutaneous mitral commissurotomy. Two months before her admission, she underwent emergency vascular surgery for leg ischaemia successfully. She was in atrial fibrillation and a severe mitral stenosis was diagnosed (mitral valve area 1 cm2, mean transmitral gradient 12 mm Hg). She received two months of oral anticoagulation with adequate international normalised ratio (INR) range. Before the procedure, transoesophageal echocardiography was performed. At least four separate thrombi were identified: one in the left appendage which was almost occluded (panel A), a smaller one, very mobile, close to the left appendage (panel B), a large one (16×26 mm) on the anterior side of the atrium near the aorta (panel C), and a very small one on the left side of the interatrial septum (panel D). Just after transoesophageal echocardiography the patient developed a stroke with complete left hemiplegia. Since she was already on oral anticoagulation with an INR > 2, and systemic thrombolysis was contraindicated, in situ fibrinolysis was performed. Unfortunately, a new cerebral embolic event occurred and the patient died two days later.
Left atrial thrombi are common complications in mitral stenosis but are usually unique and observed in the left appendage. The present case illustrates the high risk of embolic event in mitral stenosis that is not completely discarded despite adequate anticoagulation. The most efficient treatment remains an earlier management of the stenosis by percutaneous commissurotomy or surgery.