Rao, Meena P.

Background: The package insert for apixaban recommends against its use for stroke prevention in patients with atrial fibrillation (AF) with prosthetic heart valves. There are no published data on the use of apixaban in patients with AF with bioprosthetic valves. This analysis provides preliminary exploratory data on the safety and efficacy of apixaban in these patients. Methods: The ARISTOTLE trial randomized patients with AF to apixaban versus warfarin, and patients with a history of bioprosthetic valve replacement were eligible for inclusion in the trial. In this secondary analysis, baseline characteristics of patients with bioprosthetic valves were compared between apixaban and warfarin patients using Wilcoxon tests for continuous variables and chi-square tests for categorical variables. Unadjusted endpoints were compared between randomized treatments using a Cox regression model. With data collection on these valve patients ongoing, this interim report represents 82 of 260 patients with a history of valve surgery from ARISTOTLE. Results: Among 82 patients with bioprosthetic valves, 41 patients each were in the apixaban and warfarin arms. The patients had a median age of 78 years (vs. 70 years in overall trial), 18% had prior stroke (vs. 19% in overall trial), and 41% had concomitant aspirin use (vs. 31% in overall trial). Other than a higher rate of hypertension in the warfarin arm (98% vs. 81%, p=0.03), there were no statistically significant differences in baseline characteristics between the two groups. There were few events in patients with bioprosthetic valves. There were 2 stroke events, and there were no statistically significant differences between the apixaban and warfarin groups for major bleeding, stroke/systemic embolism, all-cause death, or cardiovascular death (Table). Conclusions: Among the small number of patients in ARISTOTLE with bioprosthetic valves, there were few events with similar event rates in both the apixaban and warfarin groups.

Background Patients with atrial fibrillation ( AF ) and hypertension are at high risk for stroke. Previous studies have shown elevated risk of stroke in patients with AF who have a history of hypertension (regardless of blood pressure [ BP ] control) and in patients with elevated BP . We assessed the association of hypertension and BP control on clinical outcomes. Methods and Results In ARISTOTLE (n=18 201), BP was evaluated as history of hypertension requiring treatment and elevated BP (systolic ≥140 and/or diastolic ≥90 mm Hg) at study entry and any point during the trial. Hazard ratios ( HR s) were derived from Cox proportional hazards models including BP as a time‐dependent covariate. A total of 15 916 (87.5%) patients had a history of hypertension requiring treatment. In patients with elevated BP measurement at any point during the trial, the rate of stroke or systemic embolism was significantly higher ( HR , 1.53; 95% confidence interval [ CI ], 1.25–1.86), as was hemorrhagic stroke ( HR 1.85; 95% CI , 1.26–2.72) and ischemic stroke ( HR , 1.50; 95% CI , 1.18–1.90). Rates of major bleeding were lower in patients with a history of hypertension ( HR , 0.80; 95% CI , 0.66–0.98) and nonsignificantly lower in patients with elevated BP at study entry ( HR , 0.89; 95% CI , 0.77–1.03). The benefit of apixaban versus warfarin on preventing stroke or systemic embolism was consistent among patients with and without a history of hypertension ( P interaction=0.27), BP control at baseline ( P interaction=0.43), and BP control during the trial ( P interaction=0.97). Conclusions High BP measurement at any point during the trial was independently associated with a substantially higher risk of stroke or systemic embolism. These results strongly support efforts to treat elevated BP as an important strategy to optimally lower risk of stroke in patients with AF . Clinical Trial Registration URL : https://ClinicalTrials.gov/ . Unique identifier: NCT 00412984.