Survival and Outcomes Following Bioprosthetic vs Mechanical Mitral Valve Replacement in Patients Aged 50 to 69 Years

Importance

In nonelderly patients with mitral disease requiring valve replacement, deciding between bioprosthetic and mechanical prosthetic valves is challenging because long-term survival and morbidity are not well defined.

Objective

To quantify survival and major morbidity after mitral valve replacement in patients aged 50 to 69 years.

Design, Setting, and Participants

Retrospective cohort analysis of 3433 patients (aged 50-69 years) who underwent primary, isolated mitral valve replacement in New York State hospitals from 1997-2007. Follow-up ended November 30, 2013; median duration was 8.2 years (range, 0-16.8 years). Propensity score matching for 19 baseline characteristics yielded 664 patient pairs.

Exposures

Bioprosthetic vs mechanical prosthetic mitral valve replacement.

Main Outcomes and Measures

All-cause mortality, stroke, reoperation, and major bleeding events.

Results

No survival difference was observed between use of mechanical prosthetic and bioprosthetic mitral valves in patients aged 50 to 69 years matched by propensity score (209 and 221 deaths, respectively), or in a subgroup analysis of age by decade. Actuarial 15-year survival was 57.5% (95% CI, 50.5%-64.4%) after mechanical replacement vs 59.9% (95% CI, 54.8%-65.0%) after bioprosthetic valve replacement (hazard ratio [HR], 0.95 [95% CI, 0.79-1.15],P = .62). The 15-year cumulative incidence of stroke was higher after mechanical (65 strokes; 14.0% [95% CI, 9.5%-18.6%]) vs bioprosthetic valve replacement (41 strokes; 6.8% [95% CI, 4.5%-8.8%]) (HR, 1.62; 95% CI, 1.10-2.39). The 15-year cumulative incidence of reoperation was lower for mechanical (28 reoperations; 5.0% [95% CI, 3.1%-6.9%]) compared with bioprosthetic (47 reoperations; 11.1% [95% CI, 7.6%-14.6%]) valves (HR, 0.59; 95% CI, 0.37-0.94). The 15-year cumulative incidence of a bleeding event was higher for mechanical (72 events; 14.9% [95% CI, 11.0%-18.7%) vs bioprosthetic (49 events; 9.0% [95% CI, 6.4%-11.5%]) valves (HR, 1.50; 95% CI, 1.05-2.16).

Conclusions and Relevance

Among patients aged 50 to 69 years undergoing mitral valve replacement in New York State, there was no significant survival difference at 15 years in patients matched by propensity score who underwent mechanical prosthetic vs bioprosthetic mitral valve replacement. Mechanical prosthetic valves were associated with lower risk of reoperation but greater risk of bleeding and stroke. Even though these findings suggest bioprosthetic mitral valve replacement may be a reasonable alternative to mechanical prosthetic valve replacement in patients aged 50 to 69 years, the 15-year follow-up was insufficient to fully assess lifetime risks, particularly of reoperation.