(CCSP053) SAFETY AND EFFICACY OF DIRECT ORAL ANTICOAGULANTS IN AF PATIENTS WITH NON-MECHANICAL VALVES: A COHORT STUDY (SAFE VALVE)

Background: Direct oral anticoagulants (DOACs) have been studied in non-valvular (NV) atrial fibrillation (AF) patients. Data are still lacking on their use in AF patients with non-mechanical valves (NMV), although it has been routinely prescribed over the years. We hypothesized that the use of DOACs was safe and effective in preventing stroke and systemic embolism in AF patients with NMV.

METHODS AND RESULTS: We designed a retrospective cohort study nested within the administrative healthcare databases of the province of Quebec, Canada, to assess safety and effectiveness of DOACs in AF patients with NMV procedures. Cohort entry date was defined at latest of either a) the first dispensation of DOAC or b) 3 months following the NMV procedure to exclude transitory anticoagulation. Follow-up was until end of data availability or end of exposure to DOACs. The primary outcome was occurrence of ischemic stroke or systemic thromboembolism. Secondary outcome was manifestation of major bleeding. Incidence rates and 95% confidence intervals (CI) were estimated using Poisson regression. Event rates were compared to those in patients receiving DOACs for NVAF in the same databases.

A total of 740 patients were included in the analysis. Of those, 15.3% (113 patients) received dabigatran, 32.3% (239 patients) received rivaroxaban and 52.4% (388 patients) were taking apixaban, the available drugs at the time of study. Entry dates for the cohort studies ranged from January 2009 to April 2012, and end of follow-up varied from December 2014 to March 2017. Due to low event incidence, data were pooled for all DOACs. There were 7 ischemic strokes or systemic embolisms in 764 patient-years for an incidence rate of 0.92 per 100 person-years (CI 0.44-1.92) and 15 major bleedings were noted in 754 patient-years, yielding an incidence rate of 1.99 per 100 person-years (CI 1.20-3.30) (table 1). In comparison, NVAF cohorts treated with DOACs demonstrated 554 ischemic strokes or systemic embolisms in 6707,58 patient-years, yielding an incidence rate of 0.83 per 100 person-years (CI 0.76-0.90) and 1907 major bleedings in 64178,27 patient-year for an incidence rate of 2.97 per 100 person-years (CI 2.84-3.11).

Conclusion: To our knowledge, this is the largest cohort reported of patients with NMV procedures and anticoagulated with DOACs for AF. Based on the low event rates in stroke and bleeding, and overlapping CI for incidences of outcomes in NVAF, our data support prescribing of dabigatran, rivaroxaban and apixaban in such population.