Risk of Ischemic Stroke after Intracranial Hemorrhage in Patients with Atrial Fibrillation

Background We aimed to estimate the risk of ischemic stroke after intracranial hemorrhage in patients with atrial fibrillation. Materials and Methods Using discharge data from all nonfederal acute care hospitals and emergency departments in California, Florida, and New York from 2005 to 2012, we identified patients at the time of a first-recorded encounter with a diagnosis of atrial fibrillation. Ischemic stroke and intracranial hemorrhage were identified using validated diagnosis codes. Kaplan-Meier survival statistics and Cox proportional hazard analyses were used to evaluate cumulative rates of ischemic stroke and the relationship between incident intracranial hemorrhage and subsequent stroke. Results Among 2,084,735 patients with atrial fibrillation, 50,468 (2.4%) developed intracranial hemorrhage and 89,594 (4.3%) developed ischemic stroke during a mean follow-up period of 3.2 years. The 1-year cumulative rate of stroke was 8.1% (95% CI, 7.5-8.7%) after intracerebral hemorrhage, 3.9% (95% CI, 3.5-4.3%) after subdural hemorrhage, and 2.0% (95% CI, 2.0-2.1%) in those without intracranial hemorrhage. After adjustment for the CHA(2)DS(2)-VASc score, stroke risk was elevated after both intracerebral hemorrhage (hazard ratio [HR], 2.8; 95% CI, 2.6-2.9) and subdural hemorrhage (HR, 1.6; 95% CI, 1.5-1.7). Cumulative 1-year rates of stroke ranged from 0.9% in those with subdural hemorrhage and a CHA(2)DS(2)-VASc score of 0, to 33.3% in those with intracerebral hemorrhage and a CHA(2)DS(2)-VASc score of 9. Conclusions In a large, heterogeneous cohort, patients with atrial fibrillation faced a substantially heightened risk of ischemic stroke after intracranial hemorrhage. The risk was most marked in those with intracerebral hemorrhage and high CHA(2)DS(2)-VASc scores.