Systematic review and meta-analysis of stroke and thromboembolism risk in atrial fibrillation with preserved vs. reduced ejection fraction heart failure.

Background: Stroke and thromboembolism (TE) are significant complications in patients with atrial fibrillation (AF) and heart failure (HF). The impact of ejection fraction status on these risks remains unclear. This study aims to compare the risk of stroke and TE in patients with AF and HF with preserved (HFpEF) or reduced (HFrEF) ejection fraction.

Methods: Literature search of PubMed, Embase, and Scopus databases was done for studies in adult (20 years or more) population of AF patients. Included studies had reported on the incidences of stroke and/or TE in patients with AF and associated HF with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF). Cohort (prospective and retrospective), case-control studies, and studies that were based on secondary analysis of data from a trial were eligible for inclusion. Methodological quality was assessed using the Newcastle Ottawa Scale (NOS). Pooled hazard ratio (HR) with 95% confidence intervals (CI) were reported. Exploratory analysis was conducted based on the different cut-offs used to define HFrEF and HFpEF.

Results: Twenty studies were analyzed. In the overall analysis, HFrEF in AF patients was associated with a significantly reduced risk of stroke and systemic TE (HR 0.88, 95% CI: 0.81, 0.96; n = 20, I2 = 86.6%), compared to HFpEF. However, most studies showed comparable risk of stroke among the two groups of patients except for two studies that had documented significantly reduced risk. Upon doing the sensitivity analysis by excluding these two studies, we found similar risk among the two group of subjects and with no heterogeneity (HR 1.01, 95% CI: 0.99, 1.03; n = 18, I2 = 0.0%). Exploratory analysis also showed that the risk of stroke and systemic thromboembolism was similar between those with HFpEF and HFrEF.

Conclusion: The findings suggest that there is no significantly different risk of stroke and systemic thromboembolism in cases of AF with associated HFpEF or HFrEF. The finding does not support integration of left ventricular ejection fraction into stroke risk assessments.