Author(s): Akhtar RP, Abid AR, Zafar H, Khan JS
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Abstract PURPOSE: To identify optimum international normalized ratio (INR) levels and required warfarin doses and anticoagulation-related complications in patients following mechanical prosthetic valve replacement. MATERIALS AND METHODS: Five hundred and seven patients were prospectively followed up for 10 years (2008.5 patient-years). Anticoagulation-related complications were classified into hemorrhage and thromboembolism. RESULTS: Two hundred and ninety-two (57.6\%) were males and 215 (42.4\%) were females with a mean age of 29.5 +/- 11.32 years. A total of 268 (52.9\%) patients had mitral, 96 (18.9\%) had aortic and mitral, and 76 (15\%) had aortic valve replacement (AVR). Valves implanted totaled 345 (68\%) ball and cage, 126 (24.9\%) bileaflet, and 36 (7.1\%) single disc. There were 10,669 total visits, with mean INR 2.6 +/- 0.59 and mean warfarin 5.17 +/- 1.6 mg. Sixty-four (3.2\% per patient-years) events occurred during follow-up, of which 23 (1.13\% per patient-years) events were due to thromboembolism and 41 (2.04\% per patient-years) to bleeding. Atrial fibrillation occurred in 12 (52.4\%) patients having thromboembolic events and in 24 (58.5\%) suffering from bleeding complications. Among thromboembolic events, valve thrombosis occurred in 9 patients (0.44\% per patient-years) and cerebrovascular accidents (CVAs) in 14 (0.69\% per patient-years). Atrial fibrillation was present in 7 (77.8\%) patients in the valve thrombosis group and in 5 (35.7\%) in the CVA group. Of 41 bleeding events, 8 (0.39\% per patient-years) were minor episodes, 20 (0.99\% per patient-years) were major episodes, and severe hemorrhage occurred in 5 (0.34\% per patient-years). Intracranial hemorrhage leading to CVA was seen in 8 patients (0.34\% per patient-years). There were 22 (1.1\% per patient-years) fatal hemorrhages and 15 (0.74\% per patient-years) fatal thromboembolic events. In-hospital mortality was 25 (4.9\%), and 62 (12.2\%) were late deaths; of these, 37 (7.3\%) were anticoagulation related. CONCLUSIONS: Anticoagulation for mechanical heart valve replacement can be managed with INR levels of 2-2.5 with acceptable hemorrhagic and thromboembolic events.
This article was published in Ann Thorac Cardiovasc Surg
and referenced in Journal of Anesthesia & Clinical Research