Abstract 20116: The Impact of Atrial Fibrillation Type on the Risk of Thromboembolism, Mortality and Bleeding: A Systematic Review and Meta-analysis

Abstract

Introduction: Thromboembolic risk stratification schemes and clinical guidelines for atrial fibrillation regard risk as independent of classification into paroxysmal (PAF) and nonparoxysmal atrial fibrillation (NPAF). The aim of the current study was to conduct a systematic review and meta-analysis evaluating the impact of AF type on thromboembolism, bleeding and mortality. Hypothesis: AF type would predict rates of thromebolism, mortality and bleeding. Methods: Pubmed was searched for randomized controlled trials, cohort studies, and case series reporting prospectively collected clinical outcomes stratified by AF type. The incidence of thromboembolism, mortality and bleeding was extracted. Results: AF clinical outcome data was extracted from 12 studies containing 99,996 patients. The pooled unadjusted risk ratio (RR) for thromboembolism in NPAF vs. PAF was RR 1.339 (95% CI: 1.140-1.644, P<0.001). In studies providing estimates of thromboembolism risk adjusted for baseline clinical risk factors, the pooled adjusted hazard ratio (HR) in NPAF vs. PAF was HR 1.384 (95% CI, 1.191-1.608, P<0.001). The pooled unadjusted risk ratio for all-cause mortality in NPAF vs. PAF was RR 1.462 (95% CI: 1.255-1.703 P<0.001). The pooled adjusted HR for all-cause mortality in NPAF vs. PAF was HR 1.217 (95% CI: 1.085-1.365, P<0.001. Rates of bleeding in NPAF and PAF were similar, unadjusted RR 1.00 (95% CI 0.919-1.087, P=0.994), pooled adjusted HR 1.025 (95% CI: 0.898-1.170, P=0.715). Conclusions: These data suggest a need for re-evaluation of the paradigm of thromboembolic risk equivalence between PAF and NPAF, and emphasize AF type as a powerful predictor of AF-related morbidity and mortality. Future studies exploring integration of AF type into thromboembolic risk models are needed.