Bioprosthetic versus mechanical mitral valve replacements in patients with rheumatic heart disease

Background: Rheumatic heart disease (RHD) remains a critical problem in developed countries. Few studies have compared the long-term outcomes of bioprosthetic valves and mechanical valves in patients with RHD who have received mitral valve (MV) replacement.

Methods: Patients with RHD who received MV replacement with bioprosthetic or mechanical valves were identified between 2000 and 2013 from Taiwan's National Health Insurance Research Database. The primary late outcomes of interest were all-cause mortality and redo MV surgery. Propensity score matching at a 1:1 ratio was performed.

Results: We identified 3638 patients with RHD who underwent MV replacement. Among those patients, 1075 (29.5%) and 2563 (70.5%) chose a bioprosthetic valve and mechanical valve, respectively. After matching, 788 patients were assigned to each group. No significant difference in the risk of in-hospital mortality was observed between groups (P = .920). Higher risks of all-cause mortality (10-year actuarial estimates: 50.6% vs 45.5%; hazard ratio, 1.19; 95% confidence interval, 1.01-1.41; P = .040) and MV reoperation (10-year actuarial estimates: 8.9% vs 0.93%; subdistribution hazard ratio, 4.56; 95% confidence interval, 1.71-12.17; P <.01) were observed in the bioprosthetic valve group. Furthermore, the relative mortality benefit associated with mechanical valves was more apparent in younger patients and the beneficial effect persisted until approximately 65 years of age.

Conclusions: In the patients with RHD who underwent MV replacement, mechanical valves were associated with more favorable long-term outcomes in patients younger than the age of 65 years.