Alexander, John H.

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.

Objectives Growth differentiation factor 15 (GDF-15) is a biomarker independently associated with bleeding and death in anticoagulated patients with atrial fibrillation (AF). GDF-15 is also used as one component in the more precise biomarker-based ABC (age, biomarkers, clinical history)-AF-bleeding and ABC-AF-death risk scores. Data from large trials indicate a geographic variability in regard to overall outcomes, including bleeding and mortality risk. Our aim was to assess the consistency of the association between GDF-15, ABC-AF-bleeding score and ABC-AF-death score, with major bleeding and death, across world geographic regions. Methods Data were available from 14 767 patients with AF from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial and 8651 patients with AF from the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial in this cohort study. GDF-15 was analysed from plasma samples obtained at randomisation. The geographical consistency of the associations between outcomes and GDF-15, ABC-AF-bleeding score and ABC-AF-death scores were assessed by Cox-regression models including interactions with predefined geographical region. Results GDF-15 and the ABC-AF-bleeding score were associated with major bleeding in both trials across regions (p<0.0001). Similarly, GDF-15 and the ABC-AF-death score were associated with all-cause mortality in both trials across regions (p<0.0001). Overall, the association between GDF-15, the ABC-AF-bleeding score and ABC-AF-death risk score with major bleeding and death was consistent across regions in both ARISTOTLE and the RE-LY trial cohorts. The ABC-AF-bleeding and ABC-AF-death risk scores were consistent regarding discriminative ability when comparing geographic regions in both trial cohorts. The C-indices ranged from 0.649 to 0.760 for the ABC-AF-bleeding and from 0.677 to 0.806 for the ABC-AF-death score by different geographic regions. Conclusions In patients with AF on anticoagulation, GDF-15 and the biomarker-based ABC-AF-bleeding and ABC-AF-death risk scores are consistently associated with respectively increased risk of major bleeding and death and have similar prognostic value across world geographic regions. Trial registration number ClinicalTrials.gov Registry NCT00412984 and NCT00262600.

AbstractBackgroundCardiac troponin T (cTnT) and I (cTnI) concentrations provide strong prognostic information in anticoagulated patients with atrial fibrillation (AF). Whether the associations between cardiac troponin concentrations and mortality and morbidity differ by sex is not known.ObjectivesTo assess whether men and women have different concentrations and prognostic value of cTnT and cTnI measurements in anticoagulated patients with AF.MethodscTnT and cTnI concentrations were measured with high‐sensitivity (hs) assays in EDTA plasma samples obtained from the multicentre ARISTOTLE trial, which randomized patients with AF and at least one risk factor for stroke or systemic embolic event to warfarin or apixaban. Patients were stratified according to sex and the associations between hs‐troponin concentrations, and all‐cause death, cardiac death, myocardial infarction, stroke or systemic embolic event and major bleeding were assessed in multivariable regression models.ResultsWe found higher cardiac troponin concentrations in men (n = 9649) compared to women (n = 5331), both for hs‐cTnT (median 11.8 [Q1‐3 8.1–18.0] vs. 9.6 [6.7–14.3] ng L−1, P < 0.001) and hs‐cTnI (5.8 [3.4–10.8] vs. 4.9 [3.1–8.8] ng L−1, P < 0.001). Adjusting for baseline demographics, comorbidities and medications, men still had significantly higher hs‐troponin concentrations than women. C‐reactive protein and N‐terminal pro‐B‐type natriuretic peptide concentrations were higher in female patients. Both hs‐cTnT and hs‐cTnI concentrations were associated with all clinical outcomes similarly in men and women (p‐value for interaction >0.05 for all end‐points).ConclusionMen have higher hs‐troponin concentrations than women in AF. Regardless of sex, hs‐troponin concentrations remain similarly associated with adverse clinical outcomes in anticoagulated patients with AF.

Background: The use of nonsteroidal anti-inflammatory drugs (NSAIDs) with oral anticoagulants has been associated with an increased risk of bleeding. We investigated the risk of bleeding and major cardiovascular outcomes in patients with atrial fibrillation taking NSAIDs and apixaban or warfarin. Methods: The ARISTOTLE trial (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation; n=18 201) compared apixaban with warfarin in patients with atrial fibrillation at an increased risk of stroke. Patients in ARISTOTLE without severe renal (creatine clearance ≤30 mL/min) or liver disease were included in this analysis (n=17 423). NSAID use at baseline, NSAID use during the trial (incident NSAID use), and never users were described. The primary outcome was major bleeding. Secondary outcomes included clinically relevant nonmajor bleeding, gastrointestinal bleeding, heart failure hospitalization, stroke or systemic embolism, and all-cause mortality. NSAID use during the trial, and the interaction between randomized treatment, was analyzed using time-dependent Cox proportional hazards models. Results: Those with baseline NSAID use (n=832 [4.8%]), incident NSAID use (n=2185 [13.2%]), and never users were similar in median age (age [25th, 75th]; 70 [64, 77] versus 70 [63, 75] versus 70 [62, 76]). Those with NSAID use at baseline and incident NSAID use were more likely to have a history of bleeding than never users (24.5% versus 21.0% versus 15.6%, respectively). During a median follow-up (25th, 75th) of 1.8 (1.4, 2.3) years and when excluding those taking NSAID at baseline, we found that incident NSAID use was associated with an increased risk of major bleeding (hazard ratio [HR], 1.61 [95% CI, 1.11–2.33]) and clinically relevant nonmajor bleeding (HR, 1.70 [95% CI, 1.16–2.48]), but not gastrointestinal bleeding. No significant interaction was observed between NSAID use and randomized treatment for any outcome. Conclusions: A substantial number of patients in the ARISTOTLE trial took NSAIDs. Incident NSAID use was associated with major and clinically relevant nonmajor bleeding, but not with gastrointestinal bleeding. The safety and efficacy of apixaban versus warfarin appeared not significantly to be altered by NSAID use. This study warrants more investigation of the effect of NSAIDs on the outcomes of patients treated with apixaban. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00412984.

BackgroundThe optimal anticoagulation strategy for patients with atrial fibrillation (AF) and bioprosthetic valve (BPV) replacement or native valve repair remains uncertain.HypothesisWe evaluated the safety and efficacy of apixaban vs warfarin in patients with AF and a history of BPV replacement or native valve repair.MethodsUsing data from Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) (n = 18 201), a randomized trial comparing apixaban with warfarin in patients with AF, we analyzed the subgroup of patients (n = 251) with prior valve surgery. We contacted sites by telephone to obtain additional data about prior valve surgery. Full data were available for 156 patients. The primary efficacy endpoint was stroke/systemic embolism. The primary safety endpoint was major bleeding. Treatment groups were compared using a Cox regression model.ResultsIn ARISTOTLE, 104 (0.6%) patients had a history of BPV replacement (n = 73 [aortic], n = 26 [mitral], n = 5 [mitral and aortic]) and 52 (0.3%) had a history of valve repair (n = 50 [mitral], n = 2 [aortic]). Among patients with BPVs, 55 were randomized to apixaban and 49 to warfarin. Among those with a history of native valve repair, 32 were randomized to apixaban and 20 to warfarin. Overall clinical event rates were low, with no significant differences between apixaban and warfarin for any outcomes.ConclusionsIn patients with AF and a history of BPV replacement or repair, the safety and efficacy of apixaban compared with warfarin was consistent with results from ARISTOTLE. These data suggest that apixaban may be reasonable for patients with BPVs or prior valve repair, though future larger randomized trials are needed.ClinicalTrials.govNCT00412984.

Objectives Compare the effect of apixaban and warfarin on coagulation and primary haemostasis biomarkers in atrial fibrillation (AF). Methods The biomarker substudy from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial included 4850 patients with AF randomised to treatment with apixaban or warfarin. Sixty per cent of patients used vitamin K antagonist (VKA) within 7 days before randomisation. Prothrombin fragment 1+2 (F1+2), D-dimer, soluble CD40 ligand (sCD40L) and von Willebrand factor (vWF) antigen were analysed at randomisation and after 2 months of study treatment. Results In patients not on VKA treatment at randomisation, F1+2 and D-dimer levels were decreased by 25% and 23%, respectively, with apixaban, and by 59% and 38%, respectively, with warfarin (p<0.0001 for treatment differences for both). In patients on VKA at randomisation, F1+2 and D-dimer levels increased by 41% and 10%, respectively, with apixaban and decreased by 37% and 11%, respectively, with warfarin (p<0.0001 for treatment differences for both). sCD40L levels were slightly increased at 2 months, regardless of VKA or randomised treatment. Apixaban and warfarin also both reduced vWF antigen regardless of VKA treatment. The efficacy (stroke) and safety (bleeding) of apixaban compared with warfarin was similar irrespectively of biomarker levels at 2 months. Conclusions Treatment with apixaban compared with warfarin for stroke prevention in patients with AF was associated with less reduction in thrombin generation and fibrin turnover. This effect of apixaban could contribute to the clinical results where apixaban was superior to warfarin both in stroke prevention and in reducing bleeding risk. Trial registration number NCT00412984.