Thromboembolism and mechanical heart valves: a randomized study revisited

Area of Science:

• Cardiovascular Surgery
• Biomaterials Science
• Clinical Epidemiology

Background:

• Assessing long-term safety and efficacy of mechanical heart valve prostheses is crucial.
• Previous short-term studies suggested potential differences in anticoagulant-related events.
• This study aimed to re-evaluate these differences with extended patient follow-up.

Purpose of the Study:

• To compare the incidence of anticoagulant-related thromboembolism and bleeding events among three mechanical heart valve prostheses.
• To validate or refute previous short-term findings with intermediate-term data.
• To identify factors influencing event rates after heart valve replacement.

Main Methods:

• Randomized trial with intermediate-term follow-up (median 98.5 months) in 418 patients.
• Comparison of Björk-Shiley, Edwards-Duromedics, and Medtronic-Hall mechanical heart valve prostheses.
• Multivariable analysis in the hazard function domain to assess time-related events.

Main Results:

• No significant differences in anticoagulant-related hemorrhage rates were observed among the three prostheses.
• The Medtronic-Hall prosthesis showed a higher incidence of thromboembolism in the mitral position (5.4% per patient-year) compared to Edwards-Duromedics (1.3%) and Björk-Shiley (1.2%).
• These findings contrasted with earlier short-term follow-up results.

Conclusions:

• At long-term follow-up, Medtronic-Hall prostheses in the mitral position are associated with increased thromboembolism risk.
• Björk-Shiley and Edwards-Duromedics prostheses demonstrated favorable, low rates of thromboembolism.
• These results underscore the importance of prosthesis type and position in managing anticoagulation therapy after heart valve replacement.