ISSN 2996-8215
International Journal of Cardiology | Vol. 12, No. 1, January 2021 | pp. 1–8
DOI: 10.46882/2021/IJC/000142
Original Research Article
Efficacy of Lower-Intensity Warfarin Anticoagulation After Mechanical Mitral Valve Replacement Surgery
Ahmed Al-Hassan¹, Fatima Al-Sayed¹, Sami Al-Otaibi²
¹Department of Cardiology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
²Division of Cardiac Surgery, King Abdulaziz Medical City, Riyadh, Saudi Arabia
Abstract:
Mechanical mitral valve replacement demands lifelong oral anticoagulation with vitamin K antagonists to prevent thromboembolic complications. However, standard-intensity regimens are associated with significant bleeding risks. This randomized, open-label clinical trial compared the safety and efficacy of a lower-intensity warfarin regimen versus the standard-intensity regimen in stable post-operative patients. We randomized 280 patients post-mitral valve replacement into two groups: the low-intensity group (target international normalized ratio [INR] 2.0–2.5, n = 140) or the standard-intensity group (target INR 2.5–3.5, n = 140). The primary safety endpoint was the 24-month incidence of major bleeding according to ISTH criteria, and the primary efficacy endpoint was a composite of thromboembolism, valve thrombosis, or ischemic stroke. At 24 months, the incidence of major bleeding was significantly lower in the low-intensity INR group than in the standard-intensity group (3.6% vs. 9.3%, hazard ratio: 0.38, 95% CI: 0.16–0.90, p = 0.02). The primary efficacy endpoint of thromboembolic events did not differ significantly between the cohorts (low-intensity: 2.1% vs. standard-intensity: 1.4%, hazard ratio: 1.48, 95% CI: 0.28–7.84, p = 0.64). Intracranial hemorrhage was completely absent in the lower-intensity cohort. A lower-intensity warfarin regimen targeting an INR of 2.0–2.5 safely reduces major bleeding complications compared to standard-intensity anticoagulation without a significant increase in thromboembolic risks in patients with mechanical mitral valves.
Keywords: Mechanical heart valve, Mitral valve replacement, Warfarin, Anticoagulation, International normalized ratio, Major bleeding
Received: October 10, 2020; Revised: November 24, 2020; Accepted: December 15, 2020; Published: January 18, 2021