Severe renal impairment and stroke prevention in atrial fibrillation: implications for thromboprophylaxis and bleeding risk.

The prevalence of atrial fibrillation (AF) in end-stage renal failure is high, with an increased risk of stroke among these patients with AF compared with the AF population without severe renal impairment. Many trials have shown the net clinical benefit of oral anticoagulation therapy for primary and secondary prevention of stroke in patient populations with AF. However, current stroke risk stratification schemes are based on studies that have deliberately excluded patients with severe renal impairment. Indeed, there are no large randomized controlled trials that assess the real risk/benefit of full intensity anticoagulation in patients with severe renal impairment. Also, rates of major bleeding episodes in anticoagulated hemodialysis patients with AF are high. These data are influenced by the lack of appropriate monitoring, the difficulties in maintaining the international normalized ratio target (variable between the studies), and an inaccurate bleeding classification. Thus, the limited available data may be difficult to apply to such a heterogeneous patient population, characterized by both an increased risk of bleeding and a hypercoagulability state, as seen in the patient population with severe renal impairment.