[Long-term results of isolated mitral valve replacement using bioprosthesis]

We evaluated late clinical results of 134 hospital survivors, of whom 152 patients underwent isolated mitral valve replacement with bioprosthesis from September, 1976 to July, 1989 for acquired valvular heart diseases. One hundred fifty-two bioprosthesis consisted of Hancock porcine aortic, 44, Carpentier-Edwards porcine aortic, 28 Ionescu-Shiley pericardial 46 and Carpentier-Edwards pericardial 34. The cumulative follow-up period was 1151.0 patient.year (pt.yr). The actuarial survival rate with Kaplan-Meier method was 82.4%, 79.9%, 76.0% at 5, 7 and 10 years respectively. The actuarial event free rate of primary tissue failure was 96.7%, 82.8% and 56.7% at 5, 7 and 10 years respectively. The linealized rate of bioprosthetic valve endocarditis was 0.3%/Pt.yr. Although 104 patients (77.6%) of 134 received postoperative anticoagulant therapy with Warfarin sodium about for one year. Thromboembolic complications occurred at rate of 1.3%/Pt.yr. The bioprosthesis in the mitral position is now used only in the selected patients because of the limited long term durability and necessity of permanent anticoagulant therapy.