[Optimum anticoagulation control after bileaflet mechanical valve replacement: a prospective multi-institutional...

Area of Science:

• Cardiology
• Cardiovascular Surgery
• Pharmacology

Background:

• Bileaflet mechanical heart valves require lifelong anticoagulation therapy.
• Achieving optimal anticoagulation control is essential to prevent thromboembolic and bleeding events.
• The international normalized ratio (INR) is a standard measure for monitoring warfarin therapy.

Purpose of the Study:

• To determine the optimal target range for the international normalized ratio (INR) for anticoagulation control after bileaflet mechanical heart valve replacement.
• To assess the relationship between INR levels and valve-related events, including thromboembolism and bleeding.

Main Methods:

• A prospective study involving 261 patients undergoing bileaflet mechanical heart valve replacement (St. Jude Medical and Carbomedics valves) across 8 centers in Tokyo.
• Patients were monitored for valve-related events, including thromboembolism and bleeding, over 18 months post-operation.
• Prothrombin time-international normalized ratio (PT-INR) levels were analyzed in relation to clinical outcomes.

Main Results:

• 17 valve-related events occurred: 11 thromboembolic (3.62%/pt-yr) and 5 bleeding (1.65%/pt-yr).
• Thromboembolic events were associated with PT-INR levels below 2.0.
• Bleeding events correlated with increased PT-INR or anti-platelet agent use.
• The 5-95 percentile PT-INR at 6 months for patients without events was 1.2-3.0.

Conclusions:

• An optimal PT-INR range of 1.2-3.0 is suggested for patients without high thromboembolic risk.
• A higher PT-INR range of 2.0-3.0 may be optimal for patients at high risk of thromboembolism.
• These findings aid in refining anticoagulation management strategies for mechanical heart valve recipients.