Mitral Valve Prolapse Associated With Accessory Mitral Valve
A 43-year-old man was diagnosed with accessory mitral valve (AMV) via transthoracic echocardiography (TTE), but because he had had no symptoms, his case was followed up by a cardiologist. Seventeen years later, when the patient was 60 years old, TTE and transesophageal echocardiography (TEE) revealed several AMVs and moderate mitral regurgitation due to posterior leaflet prolapse (Figure 1), but no left ventricular outflow tract obstruction was seen. Cardiac catheterization showed no pressure gradient between the left ventricle and the ascending aorta, but coronary AV fistula (right coronary artery to pulmonary artery and left anterior descending coronary artery to pulmonary artery) was found by coronary angiography.
Surgical treatment was performed electively. A right-sided left atriotomy was done during cardiopulmonary bypass. Three sac-like AMVs were attached between the papillary muscle and the mitral leaflet (2 under the anterior mitral leaflet, 1 under the posterior mitral leaflet; Figure 2). They were resected via the transmitral approach; mitral valvuloplasty was performed by attaching artificial chordae, and ring annuloplasty was performed with a 30-mm Cosgrove ring. Histological examination of the specimens confirmed that they were valve tissue with myxoid degeneration. The postoperative course was uneventful, and postoperative echocardiography showed no residual accessory tissue and only trivial mitral regurgitation.