Risks of bleeding vs. thromboembolism in patients with mechanical valves anticoagulated with warfarin

Anticoagulation with vitamin K antagonists is recommended for prevention of thromboembolism in patients with mechanical heart valves. However, this treatment carries a notable risk of bleeding. We performed a retrospective analysis of patients with mechanical heart valves who were anticoagulated with warfarin, extracting the number and type of mechanical heart valves and their time in therapeutic range (TTR) for various recommended international normalised ratio (INR) ranges. Following this, we carried out a prospective study, over two separate six-month periods, identifying those with mechanical heart valves who sustained a bleeding or thromboembolic event. We identified 409 patients with mechanical heart valves with an overall TTR of 68%. Over 12 months, we recorded 32 possible bleeding incidents in 22 patients. There was one thromboembolic event during this period, specifically a cerebrovascular event. In conclusion, while our data indicate an elevated risk of bleeding, additional larger studies are needed to better understand bleeding risks across different demographic groups.