Renato D. Lopes

Apixaban versus warfarin in patients with atrial fibrillation.

BACKGROUND Vitamin K antagonists are highly effective in preventing stroke in patients with atrial fibrillation but have several limitations. Apixaban is a novel oral direct factor Xa inhibitor that has been shown to reduce the risk of stroke in a similar population in comparison with aspirin. METHODS In this randomized, double-blind trial, we compared apixaban (at a dose of 5 mg twice daily) with warfarin (target international normalized ratio, 2.0 to 3.0) in 18,201 patients with atrial fibrillation and at least one additional risk factor for stroke. The primary outcome was ischemic or hemorrhagic stroke or systemic embolism. The trial was designed to test for noninferiority, with key secondary objectives of testing for superiority with respect to the primary outcome and to the rates of major bleeding and death from any cause. RESULTS The median duration of follow-up was 1.8 years. The rate of the primary outcome was 1.27% per year in the apixaban group, as compared with 1.60% per year in the warfarin group (hazard ratio with apixaban, 0.79; 95% confidence interval [CI], 0.66 to 0.95; P<0.001 for noninferiority; P=0.01 for superiority). The rate of major bleeding was 2.13% per year in the apixaban group, as compared with 3.09% per year in the warfarin group (hazard ratio, 0.69; 95% CI, 0.60 to 0.80; P<0.001), and the rates of death from any cause were 3.52% and 3.94%, respectively (hazard ratio, 0.89; 95% CI, 0.80 to 0.99; P=0.047). The rate of hemorrhagic stroke was 0.24% per year in the apixaban group, as compared with 0.47% per year in the warfarin group (hazard ratio, 0.51; 95% CI, 0.35 to 0.75; P<0.001), and the rate of ischemic or uncertain type of stroke was 0.97% per year in the apixaban group and 1.05% per year in the warfarin group (hazard ratio, 0.92; 95% CI, 0.74 to 1.13; P=0.42). CONCLUSIONS In patients with atrial fibrillation, apixaban was superior to warfarin in preventing stroke or systemic embolism, caused less bleeding, and resulted in lower mortality. (Funded by Bristol-Myers Squibb and Pfizer; ARISTOTLE ClinicalTrials.gov number, NCT00412984.).

Apixaban with Antiplatelet Therapy after Acute Coronary Syndrome

BACKGROUND Apixaban, an oral, direct factor Xa inhibitor, may reduce the risk of recurrent ischemic events when added to antiplatelet therapy after an acute coronary syndrome. METHODS We conducted a randomized, double-blind, placebo-controlled clinical trial comparing apixaban, at a dose of 5 mg twice daily, with placebo, in addition to standard antiplatelet therapy, in patients with a recent acute coronary syndrome and at least two additional risk factors for recurrent ischemic events. RESULTS The trial was terminated prematurely after recruitment of 7392 patients because of an increase in major bleeding events with apixaban in the absence of a counterbalancing reduction in recurrent ischemic events. With a median follow-up of 241 days, the primary outcome of cardiovascular death, myocardial infarction, or ischemic stroke occurred in 279 of the 3705 patients (7.5%) assigned to apixaban (13.2 events per 100 patient-years) and in 293 of the 3687 patients (7.9%) assigned to placebo (14.0 events per 100 patient-years) (hazard ratio with apixaban, 0.95; 95% confidence interval [CI], 0.80 to 1.11; P=0.51). The primary safety outcome of major bleeding according to the Thrombolysis in Myocardial Infarction (TIMI) definition occurred in 46 of the 3673 patients (1.3%) who received at least one dose of apixaban (2.4 events per 100 patient-years) and in 18 of the 3642 patients (0.5%) who received at least one dose of placebo (0.9 events per 100 patient-years) (hazard ratio with apixaban, 2.59; 95% CI, 1.50 to 4.46; P=0.001). A greater number of intracranial and fatal bleeding events occurred with apixaban than with placebo. CONCLUSIONS The addition of apixaban, at a dose of 5 mg twice daily, to antiplatelet therapy in high-risk patients after an acute coronary syndrome increased the number of major bleeding events without a significant reduction in recurrent ischemic events. (Funded by Bristol-Myers Squibb and Pfizer; APPRAISE-2 ClinicalTrials.gov number, NCT00831441.).

Efficacy of apixaban when compared with warfarin in relation to renal function in patients with atrial fibrillation: insights from the ARISTOTLE trial

AIMS Atrial fibrillation (AF) is common among patients with impaired renal function. Apixaban, a novel oral anticoagulant with partial renal excretion, was compared with warfarin and reduced the rate stroke, death and bleeding in the ARISTOTLE trial. We evaluated these outcomes in relation to renal function. METHODS AND RESULTS Baseline glomerular filtration rate (GFR) was estimated using the Cockcroft-Gault and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations as well as cystatin C measurements. According to baseline Cockcroft-Gault, there were 7518 patients (42%) with an estimated GFR (eGFR) of >80 mL/min, 7587 (42%) between >50 and 80 mL/min, and 3017 (15%) with an eGFR of ≤50 mL/min. The rate of cardiovascular events and bleeding was higher at impaired renal function (≤80 mL/min). Apixaban was more effective than warfarin in preventing stroke or systemic embolism and reducing mortality irrespective of renal function. These results were consistent, regardless of methods for GFR estimation. Apixaban was associated with less major bleeding events across all ranges of eGFRs. The relative risk reduction in major bleeding was greater in patients with an eGFR of ≤50 mL/min using Cockcroft-Gault {hazard ratio (HR) 0.50 [95% confidence interval (CI) 0.38-0.66], interaction P = 0.005} or CKD-EPI equations [HR 0.48 (95% CI 0.37-0.64), interaction P = 0.003]. CONCLUSION In patients with AF, renal impairment was associated with increased risk of cardiovascular events and bleeding. When compared with warfarin, apixaban treatment reduced the rate of stroke, death, and major bleeding, regardless of renal function. Patients with impaired renal function seemed to have the greatest reduction in major bleeding with apixaban.

Pulmonary Vein Isolation for the Maintenance of Sinus Rhythm in Patients with Atrial Fibrillation: a Meta-Analysis of Randomized Controlled Trials

Background—Catheter ablation is an established yet evolving nonpharmacologic intervention for the maintenance of sinus rhythm in patients with atrial fibrillation (AF). The efficacy and safety of pulmonary vein isolation (PVI) compared with medical therapy remain in question. Methods and Results—We conducted a meta-analysis of all randomized, controlled trials comparing PVI and medical therapy for the maintenance of sinus rhythm. The primary end point in this analysis was freedom from recurrent AF at 12 months. The relative efficacy of PVI was estimated using random-effects modeling according to intention to treat. We identified 6 trials that randomized a total of 693 patients with AF to PVI or control. PVI was associated with markedly increased odds of freedom from AF at 12 months of follow-up (n=266/344 [77%] versus n=102/346 [29%]; odds ratio, 9.74; 95% CI, 3.98 to 23.87). When we excluded the trial that only enrolled patients with persistent AF (Q-statistic, 2.485; P=0.647 after exclusion), PVI was associated with even greater odds of AF-free survival (15.78; 95% CI, 10.07 to 24.73). PVI was associated with a decreased hospitalization for cardiovascular causes (14 versus 93 per 100 person-years; rate ratio, 0.15; 95% CI, 0.10 to 0.23). Among those randomly assigned to PVI, 17% required a repeat PVI ablation before 12 months. The rate of major complications was 2.6% (n=9/344) in the catheter ablation group. Conclusions—Compared with a nonablation treatment strategy, PVI results in dramatically increased freedom from AF at 1 year. Although the procedure can be associated with major complications, the risk of these complications is comparable to other interventional procedures.

Incidence of and Outcomes Associated With Ventricular Tachycardia or Fibrillation in Patients Undergoing Primary Percutaneous Coronary Intervention

CONTEXT The incidence and timing of sustained ventricular tachycardia or fibrillation (VT/VF) and its impact on outcomes in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) are poorly understood. OBJECTIVE To evaluate the association of sustained VT/VF and its timing on the outcomes of patients presenting for primary PCI-an aim not prespecified in the APEX AMI trial. DESIGN, SETTING, AND PATIENTS We studied 5745 STEMI patients presenting for primary PCI at 296 hospitals in 17 countries between July 13, 2004, and May 11, 2006, from the APEX AMI trial. We categorized them into 4 groups: no VT/VF; VT/VF any time; early VT/VF, before the end of cardiac catheterization; and late VT/VF, after the end of cardiac catheterization. MAIN OUTCOME MEASURE Ninety-day total mortality. RESULTS VT/VF occurred in 329 STEMI patients (5.7%) presenting for primary PCI. The majority of these occurred before the end of catheterization (n = 205, 64%), and 90% occurred within 48 hours of presentation with symptoms of STEMI. Clinical outcomes were worse in patients with vs those without VT/VF (90-day mortality, 23.2% vs 3.6%; adjusted HR, 3.63; 95% CI, 2.59-5.09), and outcomes were worse if the VT/VF occurred late instead of early (90-day mortality for early VT/VF, 17.2% [adjusted HR, 2.34; 95% CI, 1.44-3.80]; for late VT/VF, 33.3% [adjusted HR, 5.59; 95% CI, 3.71-8.43]; for no VT/VF, 3.6% [referent]). In multivariate analyses, factors associated with early VT/VF included pre-PCI thrombolysis in MI (TIMI) flow grade 0 (HR, 2.94; 95% CI, 1.93-4.47), inferior infarction (HR, 2.16; 95% CI, 1.58-2.93), total baseline ST deviation (HR, 1.39; 95% CI, 1.19-1.63), creatinine clearance (HR, 0.88; 95% CI, 0.83-0.94), Killip class greater than I (HR, 1.88; 95% CI, 1.29-2.76), baseline systolic blood pressure (HR, 0.92; 95% CI, 0.87-0.98), body weight (HR, 1.16; 95% CI, 1.04-1.29), and baseline heart rate greater than 70/min (HR, 1.10; 95% CI, 1.01-1.20) (c index, 0.75). Factors related to late VT/VF were systolic blood pressure (HR, 0.83; 95% CI, 0.76-0.91), ST resolution less than 70% (HR, 3.17; 95% CI, 1.60-6.28), baseline heart rate greater than 70/min (HR, 1.20; 95% CI, 1.08-1.33), total baseline ST deviation (HR, 1.43; 95% CI, 1.14-1.79), post-PCI TIMI flow less than grade 3 (HR, 2.09; 95% CI, 1.24-3.52), pre-PCI TIMI flow grade 0 (HR, 2.12; 95% CI, 1.20-3.75), and beta-blockers less than 24 hours (HR, 0.52; 95% CI, 0.32-0.85) (c index, 0.74). CONCLUSIONS In this study, occurrence of VT/VF before or after the end of cardiac catheterization in patients presenting for primary PCI was associated with increased 90-day mortality.

Major bleeding in patients with atrial fibrillation receiving apixaban or warfarin: The ARISTOTLE Trial (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation): Predictors, Characteristics, and Clinical Outcomes.

OBJECTIVES This study sought to characterize major bleeding on the basis of the components of the major bleeding definition, to explore major bleeding by location, to define 30-day mortality after a major bleeding event, and to identify factors associated with major bleeding. BACKGROUND Apixaban was shown to reduce the risk of major hemorrhage among patients with atrial fibrillation in the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial. METHODS All patients who received at least 1 dose of a study drug were included. Major bleeding was defined according to the criteria of the International Society on Thrombosis and Haemostasis. Factors associated with major hemorrhage were identified using a multivariable Cox model. RESULTS The on-treatment safety population included 18,140 patients. The rate of major hemorrhage among patients in the apixaban group was 2.13% per year compared with 3.09% per year in the warfarin group (hazard ratio [HR] 0.69, 95% confidence interval [CI]: 0.60 to 0.80; p < 0.001). Compared with warfarin, major extracranial hemorrhage associated with apixaban led to reduced hospitalization, medical or surgical intervention, transfusion, or change in antithrombotic therapy. Major hemorrhage followed by mortality within 30 days occurred half as often in apixaban-treated patients than in those receiving warfarin (HR 0.50, 95% CI: 0.33 to 0.74; p < 0.001). Older age, prior hemorrhage, prior stroke or transient ischemic attack, diabetes, lower creatinine clearance, decreased hematocrit, aspirin therapy, and nonsteroidal anti-inflammatory drugs were independently associated with an increased risk. CONCLUSIONS Apixaban, compared with warfarin, was associated with fewer intracranial hemorrhages, less adverse consequences following extracranial hemorrhage, and a 50% reduction in fatal consequences at 30 days in cases of major hemorrhage.

Apixaban compared with warfarin in patients with atrial fibrillation and previous stroke or transient ischaemic attack: a subgroup analysis of the ARISTOTLE trial

BACKGROUND In the ARISTOTLE trial, the rate of stroke or systemic embolism was reduced by apixaban compared with warfarin in patients with atrial fibrillation (AF). Patients with AF and previous stroke or transient ischaemic attack (TIA) have a high risk of stroke. We therefore aimed to assess the efficacy and safety of apixaban compared with warfarin in prespecified subgroups of patients with and without previous stroke or TIA. METHODS Between Dec 19, 2006, and April 2, 2010, patients were enrolled in the ARISTOTLE trial at 1034 clinical sites in 39 countries. 18,201 patients with AF or atrial flutter were randomly assigned to receive apixaban 5 mg twice daily or warfarin (target international normalised ratio 2·0-3·0). The median duration of follow-up was 1·8 years (IQR 1·4-2·3). The primary efficacy outcome was stroke or systemic embolism, analysed by intention to treat. The primary safety outcome was major bleeding in the on-treatment population. All participants, investigators, and sponsors were masked to treatment assignments. In this subgroup analysis, we estimated event rates and used Cox models to compare outcomes in patients with and without previous stroke or TIA. The ARISTOTLE trial is registered with ClinicalTrials.gov, number NTC00412984. FINDINGS Of the trial population, 3436 (19%) had a previous stroke or TIA. In the subgroup of patients with previous stroke or TIA, the rate of stroke or systemic embolism was 2·46 per 100 patient-years of follow-up in the apixaban group and 3·24 in the warfarin group (hazard ratio [HR] 0·76, 95% CI 0·56 to 1·03); in the subgroup of patients without previous stroke or TIA, the rate of stroke or systemic embolism was 1·01 per 100 patient-years of follow-up with apixaban and 1·23 with warfarin (HR 0·82, 95% CI 0·65 to 1·03; p for interaction=0·71). The absolute reduction in the rate of stroke and systemic embolism with apixaban versus warfarin was 0·77 per 100 patient-years of follow-up (95% CI -0·08 to 1·63) in patients with and 0·22 (-0·03 to 0·47) in those without previous stroke or TIA. The difference in major bleeding with apixaban compared with warfarin was 1·07 per 100 patient-years (95% CI 0·09-2·04) in patients with and 0·93 (0·54-1·32) in those without previous stroke or TIA. INTERPRETATION The effects of apixaban versus warfarin were consistent in patients with AF with and without previous stroke or TIA. Owing to the higher risk of these outcomes in patients with previous stroke or TIA, the absolute benefits of apixaban might be greater in this population. FUNDING Bristol-Myers Squibb and Pfizer.

Efficacy and Safety of Apixaban Compared With Warfarin at Different Levels of Predicted International Normalized Ratio Control for Stroke Prevention in Atrial Fibrillation

Background— In the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial, apixaban compared with warfarin reduced stroke and systemic embolism, major bleeding, and mortality. We evaluated treatment effects in relation to 2 predictions of time in therapeutic range (TTR). Methods and Results— The trial randomized 18 201 patients with atrial fibrillation to apixaban 5 mg twice daily or warfarin for at least 12 months. For each patient, a center average TTR was estimated with the use of a linear mixed model on the basis of the real TTRs in its warfarin-treated patients, with a fixed effect for country and random effect for center. For each patient, an individual TTR was also predicted with the use of a linear mixed effects model including patient characteristics as well. Median center average TTR was 66% (interquartile limits, 61% and 71%). Rates of stroke or systemic embolism, major bleeding, and mortality were consistently lower with apixaban than with warfarin across center average TTR and individual TTR quartiles. In the lowest and highest center average TTR quartiles, hazard ratios for stroke or systemic embolism were 0.73 (95% confidence interval [CI], 0.53–1.00) and 0.88 (95% CI, 0.57–1.35) (Pinteraction=0.078), for mortality were 0.91 (95% CI, 0.74–1.13) and 0.91 (95% CI, 0.71–1.16) (Pinteraction=0.34), and for major bleeding were 0.50 (95% CI, 0.36–0.70) and 0.75 (95% CI, 0.58–0.97) (Pinteraction=0.095), respectively. Similar results were seen for quartiles of individual TTR. Conclusions— The benefits of apixaban compared with warfarin for stroke or systemic embolism, bleeding, and mortality appear similar across the range of centers’ and patients’ predicted quality of international normalized ratio control. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00412984.

Efficacy and Safety of Apixaban Compared with Warfarin at Different Levels of Predicted INR Control for Stroke Prevention in Atrial Fibrillation

Background— In the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial, apixaban compared with warfarin reduced stroke and systemic embolism, major bleeding, and mortality. We evaluated treatment effects in relation to 2 predictions of time in therapeutic range (TTR). Methods and Results— The trial randomized 18 201 patients with atrial fibrillation to apixaban 5 mg twice daily or warfarin for at least 12 months. For each patient, a center average TTR was estimated with the use of a linear mixed model on the basis of the real TTRs in its warfarin-treated patients, with a fixed effect for country and random effect for center. For each patient, an individual TTR was also predicted with the use of a linear mixed effects model including patient characteristics as well. Median center average TTR was 66% (interquartile limits, 61% and 71%). Rates of stroke or systemic embolism, major bleeding, and mortality were consistently lower with apixaban than with warfarin across center average TTR and individual TTR quartiles. In the lowest and highest center average TTR quartiles, hazard ratios for stroke or systemic embolism were 0.73 (95% confidence interval [CI], 0.53–1.00) and 0.88 (95% CI, 0.57–1.35) (Pinteraction=0.078), for mortality were 0.91 (95% CI, 0.74–1.13) and 0.91 (95% CI, 0.71–1.16) (Pinteraction=0.34), and for major bleeding were 0.50 (95% CI, 0.36–0.70) and 0.75 (95% CI, 0.58–0.97) (Pinteraction=0.095), respectively. Similar results were seen for quartiles of individual TTR. Conclusions— The benefits of apixaban compared with warfarin for stroke or systemic embolism, bleeding, and mortality appear similar across the range of centers’ and patients’ predicted quality of international normalized ratio control. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00412984.

Short- and long-term outcomes following atrial fibrillation in patients with acute coronary syndromes with or without ST-segment elevation

Objective: To assess variables associated with the occurrence of atrial fibrillation (AF) and the relation of AF with short- and long-term outcomes and with other in-hospital complications in patients with acute coronary syndromes (ACS) with and without ST-segment elevation. Design: Pooled database of 120 566 patients with ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation (NSTE) ACS enrolled in 10 clinical trials. Multivariable logistic regression and Cox proportional hazards modelling were used to identify factors associated with AF and its relation with clinical outcomes. Setting: ACS complicated by AF. Patients: 120 566 patients with STEMI and NSTE-ACS in 10 clinical trials. Interventions: None evaluated. Main outcome measure: Short- and long-term mortality. Results: Occurrence of AF was 7.5% in the overall population (STEMI 8.0% (n = 84 161); NSTE-ACS = 6.4% (n = 36 405)). Seven-day mortality was higher for patients with AF (5.1%) than for those without (1.6%). After adjusting for confounders, association of AF with 7-day mortality was present in STEMI (hazards ratio (HR) = 1.65; 95% CI 1.44 to 1.90) and NSTE-ACS (HR = 2.30; 95% CI 1.83 to 2.90; p interaction = 0.015). Risk of long-term mortality (day 8 to 1 year) was also higher in STEMI (HR = 2.37; 95% CI 1.79 to 3.15) and NSTE-ACS (HR = 1.67; 95% CI 1.41 to 1.99). AF had a larger impact in NSTE-ACS on risk of short-term mortality (p<0.001), stroke (p<0.001), ischaemic stroke (p<0.001) and moderate or severe bleeding (p<0.001). Conclusions: AF is more common in patients with STEMI. An association of AF with short- and long-term mortality among patients with STEMI and NSTE-ACS was found. Understanding these findings may lead to better care of patients with this common arrhythmia.