Elective open heart surgery in mitral stenosis: Experience with a stand-by pump oxygenator

Abstract

Primary surgery for mitral stenosis employing pump-oxygenator stand-by was performed in 42 patients. All operations were instituted as closed procedures, but whenever a satisfactory result could not be achieved, open operation with extracorporeal circulation (50 per cent hemodilution with standard 1 to 5 day old buffered banked blood) was immediately instituted. Twenty-five patients had closed operation alone. There was one operative death and no subsequent mortality. There was good leaflet pliability without calcification, fibrosis or regurgitation in 16 of these. The left atrial-left ventricular mean diastolic gradient averaged 10.7 mm. Hg before commissurotomy and 0.9 afterward. Nine patients had varying degrees of leaflet immobility, fibrosis and calcification, but open operation was not elected because of advanced age or coexisting medical problems. In this group, the left atrial-left ventricular mean diastolic gradient averaged 15.6 mm. Hg before commissurotomy and 3.9 afterward. Preoperative radiologic detection of calcification, regardless of degree, uniformly indicated that a satisfactory closed commissurotomy could not be accomplished. Open operation was performed in the majority. In 17 cases mitral valve morphology prevented satisfactory closed surgery, and open repair was immediately performed utilizing the stand-by pump-oxygenator. In all cases, the valves were heavily calcified or fibrotic. Debridement and plastic procedures on the deformed mitral valves under direct vision did not achieve satisfactory mobilization. Mitral valve excision and replacement with a Starr-Edwards prosthesis was done in all patients. Sixteen of the 17 patients who underwent valve replacement are alive and well. Anatomic and hemodynamic restoration of mitral valve function can be predictably accomplished by closed operation in patients whose valves have retained their intrinsic flexibility. The availability of a stand-by pump-oxygenator has permitted immediate application of open repair when necessary.