Personalizing Bridging Anticoagulation in Patients with Nonvalvular Atrial Fibrillation—a Microsimulation Analysis

Abstract

Background: Bridging anticoagulation is commonly prescribed to patients with atrial fibrillation who are initiating warfarin or require interruption of anticoagulation. Current guidelines recommend bridging for patients at high risk of stroke. Among patients with atrial fibrillation and one or more risk factors for ischemic stroke, the recently published BRIDGE trial found forgoing bridging during interruption to be, on average, noninferior to bridging with respect to ischemic complications, with significantly fewer hemorrhagic complications. Objective: We sought to examine the benefits and harms of bridging anticoagulation across the spectrum of ischemic and hemorrhagic stroke risk and thereby enable more nuanced, risk-stratified decision-making when bridging is considered during initiation or interruption of vitamin K antagonists. Design: A Monte Carlo simulation, using a combination of literature-derived estimates, registry data, and trial data. Main Measures: Net clinical benefit, weighting for ischemic strokes, intracranial hemorrhages, and extracranial major hemorrhages. Key Results: The benefits and harms of bridging anticoagulation vary according to underlying patient risk profiles for both thromboembolic stroke and major intracranial bleeding. Patients at high risk of ischemic stroke and low risk of hemorrhage derive benefit from bridging during initiation or interruption of warfarin therapy. Patients at similarly high or low risk of both outcomes may receive benefit from bridging during initiation and bridging during interruption, but this was sensitive to underlying assumptions. The need for stratification along both axes of risk was robust to a wide range of parameters. Conclusions: Bridging anticoagulation may provide benefit to patients at high risk of ischemic stroke and low risk of intracranial hemorrhage who are initiating or interrupting warfarin therapy, while patients at high or low risk of both complications may be harmed. The use of bridging anticoagulation in patients with non-valvular atrial fibrillation should be considered only after stratification by risk of ischemic and hemorrhagic complications.