OBJECTIVES: Patients with non-valvular atrial fibrillation (AF) who survive an intracranial hemorrhage (ICH) have an increased risk of ischemic stroke and thromboembolic events (Stroke/SE). An unanswered question is the efficacy and safety of restarting oral anticoagulant treatment (OAC), relative to not restarting in those patients. Our aim was to investigate if restarting OAC among AF patients with an ICH is linked with a lower risk of Stroke/SE and all-cause mortality, but with a small increase in major bleeding compared to not restarting OAC.

METHODS: A cohort study built using administrative data from the Quebec RAMQ and Med-Echo databases. We identified older adults using inpatient coding (ICD-9/ ICD-10) with AF from 1995 to 2014 who were discharged alive. Patient with subsequent incident ICH were included. After hospital discharge for ICH, patients were categorized as no, partial or full OAC exposure (MPR≥90%). The outcomes were the rate of stroke/SE, mortality, recurrent ICH and major bleeding after a quarantine period of 6 weeks. Crude events rates were done at 1 year of follow-up. Cox models were used to assess aHRs (95%CI).

RESULTS: A cohort of 703 AF patients with ICH was identified and aged on average at 83 years with a history of prior Stroke/SE (40%) and major bleeding (9%). The rate (per 100 person-years) of Stroke/SE, mortality, ICH and major bleeding were 2.4, 36.2, 10.6 and 1.9 for no OAC; 4.9, 33.2, 11.5, 11.2 for partial exposure; and 1.1, 3.2, 1.1 and 2.2 for full exposure. The aHR of Stroke/SE and death was 0.11 (0.05-0.28); the aHR for recurrent ICH was 0.09 (0.01-0.63) and major bleeding 0.93 (0.19-4.5) when comparing OAC full exposure to no OAC.

CONCLUSIONS: Resuming OAC after ICH seems to be associated with risk reduction of stroke/SE and mortality, supporting it use after ICH. Further analyses are ongoing to optimally control for potential confounders.