Two years' clinical experience with a quadrileaflet stentless bioprosthesis in the mitral position

Currently available bioprosthetic mitral valves do not provide sufficient durability. A new stentless pericardial prosthesis was designed for better hemodynamic performance and reduction of stress load compared with current stented bioprostheses.

Between September 1997 and August 1999, the Quadrileaflet mitral valve (QMV) was implanted in 17 patients at our institution. Four patients had minimally invasive mitral valve replacement. Mean patient age was 62.2 +/- 16.3 years; preoperative NYHA class was 3.06 +/- 0.2; ejection fraction was 64.1 +/- 14.7%. Echocardiography was performed pre-, intra- and postoperatively, and at 3-6, 12 and 24 months follow up.

Fifteen patients had an uneventful intra- and postoperative course. Two patients died, one from acute left heart failure at 6 h after surgery, and one on the first postoperative day after resuscitation for ventricular fibrillation. A small-sized prosthesis was implanted in four patients, medium-sized in eight and large-sized in five. The mean duration of cardiopulmonary bypass was 138.3 +/- 37.0 min; mean cross-clamp time was 91.3 +/- 26.3 min. Postoperative control echocardiography showed a mean valve orifice area of 2.5 +/- 0.4 cm2, transvalvular velocity (Vmax) was 1.6 +/- 0.4 m/s, and mean pressure gradient 3.6 +/- 2.0 mmHg. Echocardiographic evaluation after 3, 6 and 12 months showed no significant difference compared with the intraoperative data. Three patients had a minor mitral regurgitation (grade I-II). At 12 months all patients were in NYHA class I or II.

The implantation technique of the QMV is more demanding, but the prosthesis is a promising alternative to conventional biological mitral valve replacement. Further follow up is needed to confirm these favorable mid-term results.