弁置換術における心房室溝部の乾酪性石灰化輪状嚢のパッチ除外術

Caseous liquefaction is a rare variant of mitral annular calcification that can lead to cavity formation in the atrioventricular groove. We report a case of mitral valve replacement in a 76-year-old woman with a large caseous cavity, coronary artery disease, severe mitral valve stenosis and atrial fibrillation. Preoperative computed tomography showed a large caseous cavity (3 x 3.5 cm) in the posterior annulus extending into the atrioventricular groove. After unroofing and evacuation, the cavity was excluded with a pericardial patch. The lower edge of the patch was sutured to the ventricular side of the cavity; valve sutures passed through the residual posterior leaflet, the upper edge of the patch and the atrial edge of the cavity. The mitral prosthesis was then secured. The patient was weaned from cardiopulmonary bypass without complications. Intraoperative echocardiography demonstrated a well-seated mitral prosthesis with no valvular or paravalvular leaks. Postoperative imaging confirmed successful exclusion of the cavity in the atrioventricular groove. The postoperative echocardiogram revealed a mean gradient of 4 mmHg across the mitral prosthesis and no mitral regurgitation. Patch exclusion of the caseous cavity is a safe and feasible approach to support implanting a mitral prosthesis and obliterating a cavity.