Preventing stroke and systemic embolism in renal patients with atrial fibrillation: focus on anticoagulation

Chronic kidney disease and atrial fibrillation (AF) commonly coexist, and data suggest that renal patients have AF rates in excess of double that encountered in the general population. These patients are at increased risk of stroke, regardless of the presence or absence of AF. Furthermore, a lower GFR causes increased thromboembolic risk in patients with AF - independent of other risk factors. The dilemma facing clinicians treating this cohort of patients is that renal insufficiency confers both a thromboembolic and a bleeding risk. Renal disease also commonly coexists with other risk factors for stroke and bleeding such as hypertension and advanced age. Furthermore, bleeding risk tracks stroke risk and many risk factors are common to both thromboembolism and haemorrhage. Patients with severe renal impairment are also actively excluded from the majority of trials for stroke prevention in AF, including those trials which informed the development of stroke risk factor scoring schemes. Therefore, patients with renal disease and AF present a unique management challenge. The available data suggests that the benefit from warfarin in terms of stroke reduction is not as clear as in the general population, and there is an increased risk of bleeding complications and even ectopic vascular calcification. Thus, it is problematic to extrapolate the benefits of warfarin in the general population to a subgroup that has been actively excluded from clinical trials. The new oral anticoagulants have relatively little data in patients with severe renal impairment, and all have an element of renal excretion. There is a need for large randomised control trials in patients with renal insufficiency and on haemodialysis to provide a bank of high-quality scientific data on which clinicians can base their management decisions. Until then, we must adopt a pragmatic approach which involves careful consideration of the relative risk of stroke and bleeding in each individual patient.