Long-Term Follow-up of the Björk-Shiley Prosthetic Valve Used in the Mitral Position

Abstract

This study analyzes 547 patients who had mitral valve replacement with a Björk-Shiley prosthesis over a 9-year period (mean follow-up, 46.5 months). Operative mortality was 7.3%, and 5-year survival was 76.9%. Serious anticoagulation problems occurred in 1.8% (10 patients) and serious thromboembolic episodes in 5.3% (28 patients) (1.3 per 1,000 patient-months). The study includes 257 patients with isolated mitral valve replacement (Group 1) and 290 who had associated procedures (Groups 2 through 5). Hospital mortality in Group 1 was 2.7% compared with 11.7% in Groups 2 through 5 ( p < 0.01). Five-year survival for Group 1 was 83.9% and for the others, 70.5% ( p < 0.01), and two-thirds of the deaths occurred in Groups 2 through 5. In the patients in Group 1 with pure mitral insufficiency (MI), 5-year survival was 70.9%, significantly lower ( p < 0.05) than the 90.2% for those with pure mitral stenosis (MS) and 84.3% for those with combined stenosis and insufficiency (MI + MS). In Groups 2 through 5, 5-year survivals were 56.0% (MI), 82.5% (MS), and 71.4% (MI + MS). Significantly lower ( p < 0.01) 5-year survival was found for those in Functional Class IV preoperatively compared with Class III or II. In Group 1, 89.1% were in Class II, 86.7% in Class III, and 64.8% in Class IV. The corresponding figures in the combined other groups were 72.7%, 76.4%, and 48.9%, respectively. This study shows that rhythm plays a small role in thromboembolic episodes and survival and that there is strong evidence for early operation in patients with MI.