A rare cause of severe mitral regurgitation: mitral valve aneurysm

Perforation of a mitral valve aneurysm is a rare cause of acute mitral regurgitation, and valvular aneurysm formation and its rupture without infectious involvement are unusual. An 80-year-old man was admitted with acute onset and progressive dyspnea. He had no history of chest pain, palpitation, or fever. Laboratory findings did not suggest any signs of infection. Transthoracic echocardiography revealed an aneurysm of the mitral septal leaflet protruding into the left atrium during systole and color-flow Doppler ultrasonography showed severe mitral regurgitation. There was no aortic regurgitation nor evidence for rheumatic involvement of the valvular structures. Pulmonary artery systolic pressure estimated from the tricuspid regurgitation jet was 50 mmHg. Transesophageal echocardiography showed a saccular, thin-walled, mitral valve aneurysm on the atrial surface, expanding during systole and a small tissue defect on the aneurysmatic segment of the mitral leaflet. There were no signs of connective tissue disease. The patient was submitted to surgery. The aneurysmatic and perforated parts on the septal leaflet were resected and an annuloplasty ring was placed. The histopathological examination of the mitral valve tissue showed nonspecific degenerative changes. The postoperative period was uneventful and the patient was discharged on the fifth postoperative day.