Avezum, Álvaro

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.

Objective To assess stroke/systemic embolism, major bleeding and other outcomes, and treatment effect of apixaban versus warfarin, in patients with atrial fibrillation (AF) and different types of valvular heart disease (VHD), using data from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial. Methods There were 14 793 patients with known VHD status, categorised as having moderate or severe mitral regurgitation (MR) (n=3382), aortic regurgitation (AR) (n=842) or aortic stenosis (AS) (n=324); patients with moderate or severe mitral stenosis were excluded from the trial. Baseline characteristics, efficacy and safety outcomes were compared between each type and no significant VHD. Treatment effect was assessed using an adjusted model. Results Patients with MR or AR had similar rates of stroke/systemic embolism and bleeding compared with patients without MR or AR, respectively. Patients with AS had significantly higher event rates (presented as rate per 100 patient-years of follow-up) of stroke/systemic embolism (3.47 vs 1.36; adjusted HR (adjHR) 2.21, 95% CI 1.35 to 3.63), death (8.30 vs 3.53; adjHR 1.92, 95% CI 1.41 to 2.61), major bleeding (5.31 vs 2.53; adjHR 1.80, 95% CI 1.19 to 2.75) and intracranial bleeding (1.29 vs 0.51; adjHR 2.54, 95% CI 1.08 to 5.96) than patients without AS. The superiority of apixaban over warfarin on stroke/systemic embolism was similar in patients with versus without MR (HR 0.69, 95% CI 0.46 to 1.04 vs HR 0.79, 95% CI 0.63 to 1.00; interaction P value 0.52), with versus without AR (HR 0.57, 95% CI 0.27 to 1.20 vs HR 0.78, 95% CI 0.63 to 0.96; interaction P value 0.52), and with versus without AS (HR 0.44, 95% CI 0.17 to 1.13 vs HR 0.79, 95% CI 0.64 to 0.97; interaction P value 0.19). For each of the primary and secondary efficacy and safety outcomes, there was no evidence of a different effect of apixaban over warfarin in patients with any VHD subcategory. Conclusions In anticoagulated patients with AF, AS is associated with a higher risk of stroke/systemic embolism, bleeding and death. The efficacy and safety benefits of apixaban compared with warfarin were consistent, regardless of presence of MR, AR or AS. Clinical trial registration ARISTOTLE clinical trial number NCT00412984.

Background— Apixaban is approved for the prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. However, the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial included a substantial number of patients with valvular heart disease and only excluded patients with clinically significant mitral stenosis or mechanical prosthetic heart valves. Methods and Results— We compared the effect of apixaban and warfarin on rates of stroke or systemic embolism, major bleeding, and death in patients with and without moderate or severe valvular heart disease using Cox proportional hazards modeling. Of the 18 201 patients enrolled in ARISTOTLE, 4808 (26.4%) had a history of moderate or severe valvular heart disease or previous valve surgery. Patients with valvular heart disease had higher rates of stroke or systemic embolism and bleeding than patients without valvular heart disease. There was no evidence of a differential effect of apixaban over warfarin in patients with and without valvular heart disease in reducing stroke and systemic embolism (hazard ratio [HR], 0.70; 95% confidence interval [CI], 0.51–0.97 and HR, 0.84; 95%, CI 0.67–1.04; interaction P =0.38), causing less major bleeding (HR, 0.79; 95% CI, 0.61–1.04 and HR, 0.65; 95% CI, 0.55–0.77; interaction P =0.23), and reducing mortality (HR, 1.01; 95% CI, 0.84–1.22 and HR, 0.84; 95% CI, 0.73–0.96; interaction P =0.10). Conclusions— More than a quarter of the patients in ARISTOTLE with nonvalvular atrial fibrillation had moderate or severe valvular heart disease. There was no evidence of a differential effect of apixaban over warfarin in reducing stroke or systemic embolism, causing less bleeding, and reducing death in patients with and without valvular heart disease. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00412984.