Outcomes after conversion from mechanical to bioprosthetic valves for anticoagulation-related complications

Conversion from mechanical to bioprosthetic valves is sometimes pursued for anticoagulation-related complications, yet outcomes after such conversion remain poorly characterized.

We analyzed 62 consecutive patients undergoing mechanical-to-bioprosthetic valve replacement owing to major bleeding, recurrent thromboembolism, or nonbleeding/nonthromboembolic warfarin-related difficulty between 2000 and 2005. The primary endpoint was time to first postoperative bleeding or thromboembolic event, with death treated as a competing risk. Survival was estimated using Kaplan-Meier analysis.

The median interval from mechanical valve implantation to conversion was 7 years (interquartile range, 1-17 years). Fifty-eight percent of procedures were urgent or emergent, and hospital mortality was 13%. Among hospital survivors, 66% were discharged on and remained on warfarin therapy beyond 3 months. Overall survival was 82% at 1 year and 71% at 5 years. The 5-year cumulative incidence of bleeding or thromboembolism was 27%, with 63% of events occuring while patients were receiving warfarin.

Conversion from a mechanical valve to a bioprosthetic valve for anticoagulation-related complications carries substantial early risk and frequently does not eliminate the need for anticoagulation. Recurrent bleeding and thromboembolic events remain clinically significant, underscoring the importance of careful patient counseling and shared decision making.