XANTUS: rationale and design of a noninterventional study of rivaroxaban for the prevention of stroke in patients with atrial fibrillation.

Atrial fibrillation (AF) is associated with a fivefold increase in the risk of stroke. The Phase III ROCKET AF (Rivaroxaban Once-Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation) trial showed that rivaroxaban, an oral, direct Factor Xa inhibitor, was noninferior to warfarin for the reduction of stroke or systemic embolism in patients with AF. Compared with warfarin, rivaroxaban significantly reduced rates of intracranial and fatal hemorrhages, although not rates of bleeding overall. XANTUS (Xarelto(®) for Prevention of Stroke in Patients with Atrial Fibrillation) is a prospective, international, observational, postauthorization, noninterventional study designed to collect safety and efficacy data on the use of rivaroxaban for stroke prevention in AF in routine clinical practice. The key goal is to determine whether the safety profile of rivaroxaban established in ROCKET AF is also observed in routine clinical practice. XANTUS is designed as a single-arm cohort study to minimize selection bias, and will enroll approximately 6,000 patients (mostly from Europe) with nonvalvular AF prescribed rivaroxaban, irrespective of their level of stroke risk. Overall duration of follow-up will be 1 year; the first patient was enrolled in June 2012. Similar studies (XANTUS-EL [Xarelto(®) for Prevention of Stroke in Patients with Nonvalvular Atrial Fibrillation, Eastern Europe, Middle East, Africa and Latin America] and XANAP [Xarelto(®) for Prevention of Stroke in Patients with Atrial Fibrillation in Asia-Pacific]) are ongoing in Latin America and Asia-Pacific. Data from these studies will supplement those from ROCKET AF and provide practical information concerning the use of rivaroxaban for stroke prevention in AF

Impact of Modifiable Bleeding Risk Factors on Major Bleeding in Patients With Atrial Fibrillation Anticoagulated With Rivaroxaban.

Background Reducing major bleeding events is a challenge when managing anticoagulation in patients with atrial fibrillation. This study evaluated the impact of modifiable and nonmodifiable bleeding risk factors in patients with atrial fibrillation receiving rivaroxaban and estimated the impact of risk factor modification on major bleeding events. Methods and Results Modifiable and nonmodifiable risk factors associated with major bleeding events were identified from the XANTUS (Xarelto for Prevention of Stroke in Patients With Atrial Fibrillation) prospective registry data set (6784 rivaroxaban-treated patients). Parameters showing univariate association with bleeding were used to construct a multivariable model identifying independent risk factors. Modeling was used to estimate attributed weights to risk factors. Heavy alcohol use (hazard ratio [HR]=2.37; 95% CI 1.24-4.53); uncontrolled hypertension (HR after parameter-wise shrinkage=1.79; 95% CI 1.05-3.05); and concomitant treatment with antiplatelets, nonsteroidal anti-inflammatory drugs, or paracetamol (HR=1.80; 95% CI 1.24-2.61) were identified as modifiable, independent bleeding risk factors. Increasing age (HR=1.25 [per 5-year increment]; 95% CI 1.12-1.38); heart failure (HR=1.97; 95% CI 1.36-2.86); and vascular disease (HR=1.91; 95% CI 1.32-2.77) were identified as nonmodifiable bleeding risk factors. Overall, 128 (1.9%) patients experienced major bleeding events; of these, 11% had no identified bleeding risk factors, 50% had nonmodifiable bleeding risk factors only, and 39% had modifiable bleeding risk factors (with or without nonmodifiable risk factors). The presence of 1 modifiable bleeding risk factor doubled the risk of major bleeding. Conclusions Elimination of modifiable bleeding risk factors is a potentially effective strategy to reduce bleeding risk in atrial fibrillation patients receiving rivaroxaban. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT01606995

An evaluation of exact matching and propensity score methods as applied in a comparative effectiveness study of inhaled corticosteroids in asthma

Peer reviewedPublisher PD

Left atrial thrombus resolution in atrial fibrillation or flutter:Results of a prospective study with rivaroxaban (X-TRA) and a retrospective observational registry providing baseline data (CLOT-AF)

BackgroundData on left atrial/left atrial appendage (LA/LAA) thrombus resolution after non–vitamin K antagonist (VKA) oral anticoagulant treatment are scarce. The primary objective of X-TRA was to explore the use of rivaroxaban for the resolution of LA/LAA thrombi in patients with nonvalvular atrial fibrillation (AF) or atrial flutter, with the CLOT-AF registry providing retrospective data after standard-of-care therapy in this setting.MethodsX-TRA was a prospective, single-arm, open-label, multicenter study that investigated rivaroxaban treatment for 6 weeks for LA/LAA thrombus resolution in patients with nonvalvular AF or atrial flutter and LA/LAA thrombus confirmed at baseline on a transesophageal echocardiogram (TEE). CLOT-AF retrospectively collected thrombus-related patient outcome data after standard-of-care anticoagulant treatment for 3 to 12 weeks in patients with nonvalvular AF or atrial flutter who had LA/LAA thrombi on TEE recorded in their medical file.ResultsIn X-TRA, patients were predominantly (95.0%) from Eastern European countries. The adjudicated thrombus resolution rate was 41.5% (22/53 modified intention-to-treat [mITT] patients, 95% CI 28.1%-55.9%) based on central TEE assessments. Resolved or reduced thrombus was evident in 60.4% (32/53 mITT patients, 95% CI 46.0%-73.6%) of patients. In CLOT-AF, the reported thrombus resolution rate was 62.5% (60/96 mITT patients, 95% CI 52.0%-72.2%) and appeared better in Western European countries (34/50; 68.0%) than in Eastern European countries (26/46; 56.5%).ConclusionX-TRA is the first prospective, multicenter study examining LA/LAA thrombus resolution with a non-VKA oral anticoagulant in VKA-naïve patients or in patients with suboptimal VKA therapy. Rivaroxaban could be a potential option for the treatment of LA/LAA thrombi

Dronedarone in patients with congestive heart failure: insights from ATHENA

Dronedarone is a new multichannel blocking antiarrhythmic drug for treatment of atrial fibrillation (AF). In patients with recently decompensated congestive heart failure (CHF) and depressed LV function, the drug was associated with excess mortality compared with a placebo group. The present study aimed to analyse in detail the effects of dronedarone on mortality and morbidity in AF patients CHF. We performed a post hoc analysis of ATHENA, a large placebo-controlled outcome trial in 4628 patients with paroxysmal or persistent AF, to evaluate the relationship between clinical outcomes and dronedarone therapy in patients with stable CHF. The primary outcome was time to first cardiovascular (CV) hospitalization or death. There were 209 patients with NYHA class II/III CHF and a left ventricular ejection fraction <0.40 at baseline (114 placebo, 95 dronedarone patients). A primary outcome event occurred in 59/114 placebo patients compared with 42/95 dronedarone patients [hazard ratio (HR) 0.78, 95% CI = 0.52-1.16]. Twenty of 114 placebo patients and 12/95 dronedarone patients died during the study (HR 0.71, 95% CI = 0.34-1.44). Fifty-four placebo and 42 dronedarone patients were hospitalized for an intermittent episode of NYHA class IV CHF (HR = 0.78, 95% CI = 0.52-1.17). In this post-hoc analysis of ATHENA patients with AF and stable CHF, dronedarone did not increase mortality and showed a reduction of CV hospitalization or death similar to the overall population. However, in the light of the ANtiarrhythmic trial with DROnedarone in Moderate to severe CHF Evaluating morbidity DecreAse study, dronedarone should be contraindicated in patients with NYHA class IV or unstable NYHA classes II and III CHF