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Background and Objective: Rivaroxaban is an oral, direct Factor Xa inhibitor, which is at an advanced stage of clinical development for prevention and treatment of thromboembolic disorders. Two phase II studies, ODIXa-DVT and EINSTEIN DVT, assessed the efficacy and safety of oral rivaroxaban (once daily or twice daily) for treatment of acute deep-vein thrombosis (DVT). Population pharmacokinetic and pharmacodynamic analyses of rivaroxaban in patients in these two phase II studies were conducted to characterize the pharmacokinetics/pharmacodynamics of rivaroxaban and the relationship between important patient covariates and model parameters. Exposure simulations in patients with atrial fibrillation (AF) were also performed in order to predict the exposure of rivaroxaban, using modified demographic data reflecting the characteristics of a typical AF population.Methods: A population pharmacokinetic model was developed using plasma samples from these patients. Various simulations were conducted to explore the pharmacokinetics of rivaroxaban in patients with DVT and to predict exposure in those with AF. Correlations between plasma rivaroxaban concentrations and the prothrombin time, Factor Xa activity, HepTest® and activated partial thromboplastin time were also described.Results: The pharmacokinetics of rivaroxaban in patients with DVT were found to be consistent and predictable across all doses studied. The area under the plasma concentration-time curve (AUC) increased dose dependently. The same total daily doses given once daily achieved higher maximum plasma concentration (C(max)) values (∼20%) and lower trough (minimum) plasma concentration (C(trough)) values (∼60%) than when given twice daily; however, the 5th-95th percentile ranges for these parameters overlapped. Rivaroxaban clearance was moderately influenced by age and renal function, and the volume of distribution was influenced by age, body weight and sex; the effects were within the observed interindividual variability. Simulations in virtual patient populations with AF showed that a rivaroxaban dose of 15 mg once daily in patients with creatinine clearance of 30-49 mL/min would achieve AUC and C(max) values similar to those observed with 20 mg once daily in patients with normal renal function. The prothrombin time correlated almost linearly with plasma rivaroxaban concentrations (≤500 μg/L).Conclusion: Population analyses of phase II clinical data indicated that the pharmacokinetics and pharmacodynamics of all rivaroxaban doses were predictable and were affected by expected demographic factors in patients with acute DVT. [ABSTRACT FROM AUTHOR]

Background: The optimal duration of oral anticoagulant therapy in patients with deep venous thrombosis (DVT) of the lower extremities remains uncertain.Objective: To assess whether tailoring the duration of anticoagulation on the basis of the persistence of residual thrombi on ultrasonography reduces the rate of recurrent venous thromboembolism (VTE) compared with the administration of conventional fixed-duration treatment in adults with proximal DVT.Design: Parallel, randomized trial from 1999 to 2006. Trained physicians who assessed outcomes were blinded to patient assignment status, but patients and providers were not.Setting: 9 university or hospital centers in Italy.Patients: 538 consecutive outpatients with a first episode of acute proximal DVT at completion of an uneventful 3-month period of anticoagulation.Intervention: Patients were randomly assigned (stratified by center and secondary vs. unprovoked DVT by using a computer-generated list that was accessible only to a trial nurse) to fixed-duration anticoagulation (no further anticoagulation for secondary thrombosis and an extra 3 months for unprovoked thrombosis) or flexible-duration, ultrasonography-guided anticoagulation (no further anticoagulation in patients with recanalized veins and continued anticoagulation in all other patients for up to 9 months for secondary DVT and up to 21 months for unprovoked thrombosis). For the primary outcome assessment, 530 patients completed the trial.Measurements: The rate of confirmed recurrent VTE during 33 months of follow-up.Results: Overall, 46 (17.2%) of 268 patients allocated to fixed-duration anticoagulation and 32 (11.9%) of 270 patients allocated to flexible-duration anticoagulation developed recurrent VTE (adjusted hazard ratio [HR], 0.64 [95% CI, 0.39 to 0.99]). For patients with unprovoked DVT, the adjusted HR was 0.61 (CI, 0.36 to 1.02) and 0.81 (CI, 0.32 to 2.06) for those with secondary DVT. Major bleeding occurred in 2 (0.7%) patients in the fixed-duration group and 4 (1.5%) patients in the flexible-duration group (P = 0.67).Limitations: The trial lacked a double-blind design. The sample size was not powered to detect differences in bleeding between groups and to detect effectiveness of the intervention in the subgroups of patients with unprovoked and secondary DVT. Patients with previous thromboembolism, permanent risk factors for thrombosis, and thrombophilic abnormalities other than factor V Leiden and prothrombin mutation were excluded.Conclusion: Tailoring the duration of anticoagulation on the basis of ultrasonography findings reduces the rate of recurrent VTE in adults with proximal DVT.Primary Funding Source: None. [ABSTRACT FROM AUTHOR]

Background: Risks of recurrence and major bleeding with extended anticoagulation in Asian patients with venous thromboembolism (VTE) are similar to those in non-Asian patients but risks according to baseline risk factor profiles is not well documented., Methods: Subgroup analysis of two randomized trials, which compared once-daily rivaroxaban (20 mg or 10 mg) with placebo or aspirin (100 mg) for extended treatment in Asian patients with VTE who had completed 6-12 months of anticoagulation. Index events were classified as unprovoked, provoked by major persistent risk factors, minor persistent risk factors, minor transient risk factors, or major transient risk factors. One-year cumulative risks of recurrent VTE were calculated for these risk factor profiles., Results: 367 patients received rivaroxaban, 159 aspirin, and 48 placebo. For patients with unprovoked VTE, one-year cumulative incidences of recurrence in the 202 patients given rivaroxaban, the 89 given aspirin and the 28 given placebo were 1.6%, 5.8%, and 14.8%, respectively. For patients with VTE provoked by minor persistent risk factors, these incidences were 0% in the 74 patients given rivaroxaban, 9.3% in the 36 given aspirin, and 0% in the 12 given placebo. No recurrent VTE occurred in patients with VTE provoked by major persistent or transient risk factors or minor transient risk factors. Rivaroxaban was not associated with a significant increase in major bleeding., Conclusions: Rivaroxaban seems to be an effective and safe option for extended treatment in Asian patients, especially those presenting with unprovoked VTE. Subgroups of patients with provoked risk factors were too small to draw meaningful conclusions., Trial Registration: NCT00439725 and NCT02064439., (© 2024. The Author(s).)

Background: The results of the EINSTEIN-DVT/PE and AMPLIFY trials, which compared rivaroxaban and apixaban with conventional anticoagulation therapy for acute venous thromboembolism (VTE), respectively, are often compared. However, the trials differed in duration of therapy (3-12 and 6months, respectively) and in patient selection (few exclusion criteria and more stringent exclusion criteria, respectively)., Methods: To determine the effect of these methodological differences on outcomes, the patients enrolled in EINSTEIN-DVT/PE were divided into 2 cohorts; the 5253 patients that matched the exclusion criteria for AMPLIFY and were treated for at least 6months (cohort 1) and the 2368 patients who would have been ineligible for AMPLIFY (cohort 2)., Results: Compared with patients in cohort 2, those in cohort 1 were older and more often male and there were more with unprovoked VTE, prior VTE, cancer and known thrombophilia. In cohort 1, rivaroxaban would have significantly reduced recurrent VTE (relative risk [RR], 0.64; 95% confidence interval [CI], 0.43-0.95) and major bleeding (RR, 0.50; 95% CI, 0.30-0.82) compared with conventional therapy, whereas the two treatments would have had similar effects on recurrent VTE (RR, 1.08; 95% CI, 0.65-1.79) and major bleeding (RR, 1.03; 95% CI, 0.48-2.18) in cohort 2., Conclusions: This analysis illustrates the influence of patient selection and treatments duration on outcome results and highlights the limitations of cross-trial comparisons., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: The prevalence of pulmonary embolism among patients hospitalized for syncope is not well documented, and current guidelines pay little attention to a diagnostic workup for pulmonary embolism in these patients., Methods: We performed a systematic workup for pulmonary embolism in patients admitted to 11 hospitals in Italy for a first episode of syncope, regardless of whether there were alternative explanations for the syncope. The diagnosis of pulmonary embolism was ruled out in patients who had a low pretest clinical probability, which was defined according to the Wells score, in combination with a negative d-dimer assay. In all other patients, computed tomographic pulmonary angiography or ventilation-perfusion lung scanning was performed., Results: A total of 560 patients (mean age, 76 years) were included in the study. A diagnosis of pulmonary embolism was ruled out in 330 of the 560 patients (58.9%) on the basis of the combination of a low pretest clinical probability of pulmonary embolism and negative d-dimer assay. Among the remaining 230 patients, pulmonary embolism was identified in 97 (42.2%). In the entire cohort, the prevalence of pulmonary embolism was 17.3% (95% confidence interval, 14.2 to 20.5). Evidence of an embolus in a main pulmonary or lobar artery or evidence of perfusion defects larger than 25% of the total area of both lungs was found in 61 patients. Pulmonary embolism was identified in 45 of the 355 patients (12.7%) who had an alternative explanation for syncope and in 52 of the 205 patients (25.4%) who did not., Conclusions: Pulmonary embolism was identified in nearly one of every six patients hospitalized for a first episode of syncope. (Funded by the University of Padua; PESIT ClinicalTrials.gov number, NCT01797289 .).

The pharmacokinetics of oral rivaroxaban are highly predictable and only affected to a limited extent by bodyweight; therefore, dose adjustments for bodyweight are not required. However, this raises concerns among physicians for potential under- or overdosing. This substudy of the randomised EINSTEIN DVT and EINSTEIN PE trials, which compared rivaroxaban with enoxaparin/vitamin K antagonist (VKA) therapy, aimed to determine the incidence of major bleeding in patients with a low bodyweight and recurrent venous thromboembolism (VTE) in patients with a high bodyweight during rivaroxaban or enoxaparin/VKA therapy. More than 8,000 patients with objectively diagnosed deep-vein thrombosis or pulmonary embolism were included. Adjusted hazard ratios for recurrent VTE and bleeding were calculated using the Cox proportional hazards model. Analyses were performed for both the first 21 days of treatment and the whole treatment period. For rivaroxaban recipients, there was no association between bodyweight or body mass index (BMI) and risk of recurrent VTE (ptrend=0.87 and 0.62, respectively), major bleeding (ptrend=0.24 and 0.36, respectively) or clinically relevant bleeding (ptrend=0.17 and 0.63, respectively). Major bleeding events were numerically lower in rivaroxaban patients across all bodyweight and BMI categories. Hazard ratios for rivaroxaban vs enoxaparin/VKA were similar in all bodyweight and BMI categories, both during the first 21 days and the whole treatment period. The fixed-dose rivaroxaban regimen is not associated with an increased risk of major bleeding or recurrent VTE in patients with either a low or high bodyweight. A high BMI was not associated with an increased risk of recurrent VTE during anticoagulation.

Post-thrombotic syndrome (PTS) is a common complication of deep-vein thrombosis (DVT). Poor quality treatment with vitamin K antagonists (VKA) is a risk factor for PTS. We hypothesised that treatment with the direct oral anticoagulant (DOAC) rivaroxaban may lower PTS incidence as compared to enoxaparin/VKA, as DOACs have a more stable pharmacologic profile than VKA. We performed a post-hoc subgroup analysis of the Einstein DVT trial (n=3449). Kaplan-Meier survival analysis was performed to compare the cumulative incidence of PTS between the rivaroxaban and enoxaparin/VKA groups. Hazard ratios (HR) and 95 % confidence intervals (CI) were calculated using Cox proportional hazards models. We included 336 patients with a mean age of 58 ± 16 years and a median follow-up after index DVT of 57 months (interquartile range 48-64). Of these, 162 (48 %) had been treated with rivaroxaban and 174 (52 %) with enoxaparin/VKA. The cumulative PTS incidence at 60 months follow-up was 29 % in the rivaroxaban group and 40 % in the enoxaparin/VKA group. After adjusting for age, gender, body mass index, previous VTE, ipsilateral recurrent DVT, extent of DVT, idiopathic DVT, duration of anticoagulant treatment, compliance to assigned study medication, elastic compression stocking use and active malignancy, the HR of PTS development for rivaroxaban was 0.76 (95 % CI: 0.51-1.13). In conclusion, treatment of acute DVT with rivaroxaban was associated with a numerically lower but statistically non-significant risk of PTS compared to enoxaparin/VKA treatment. The potential effect on reducing PTS deserves evaluation in a large randomised trial.

Women receiving vitamin K antagonists (VKAs) require adequate contraception because of the potential for fetal complications. It is unknown whether the use of hormonal therapy, especially those containing estrogens, is associated with recurrent venous thromboembolism (VTE) during anticoagulation. Despite the absence of data, World Health Organization guidelines state that use of estrogen-containing contraceptives confers an "unacceptable health risk" during established anticoagulation for VTE. We compared the incidences of recurrent VTE and abnormal uterine bleeding with and without concomitant hormonal therapy in women aged <60 years who were receiving anticoagulation with rivaroxaban or enoxaparin/VKA for confirmed VTE. Incidence densities in percentage per year were computed for the on and off estrogen-containing or progestin-only therapy periods. Cox regression models were fitted, with hormonal therapy (on vs off) as a time-dependent variable to derive the hazard ratio (HR) for the effects on recurrent VTE and abnormal uterine bleeding. In total, 1888 women were included. VTE incidence densities on and off hormonal therapy were 3.7%/year and 4.7%/year (adjusted HR, 0.56; 95% confidence interval [CI], 0.23-1.39), respectively, and were 3.7%/year and 3.8%/year, respectively, for estrogen-containing and progestin-only therapy. The adjusted HR for all abnormal uterine bleeding (on vs off hormonal therapy) was 1.02 (95% CI, 0.66-1.57). Abnormal uterine bleeding occurred more frequently with rivaroxaban than with enoxaparin/VKA (HR, 2.13; 95% CI, 1.57-2.89). Hormonal therapy was not associated with an increased risk of recurrent VTE in women receiving therapeutic anticoagulation. The observed increased risk of abnormal uterine bleeding with rivaroxaban needs further exploration., (© 2016 by The American Society of Hematology.)

Objectives: Outpatient treatment of acute venous thromboembolism (VTE) requires the selection of patients with a low risk of bleeding during the first few weeks of anticoagulation. The accuracy of four systems, originally derived for predicting bleeding in VTE treated with vitamin K antagonists (VKAs), was assessed in VTE patients treated with rivaroxaban., Methods: All patients treated with rivaroxaban in the multinational EINSTEIN deep vein thrombosis (DVT) and pulmonary embolism (PE) trials were included. Major bleeding was defined as ≥2 g/dL drop in hemoglobin or ≥2-unit blood transfusion, bleeding in critical area, or bleeding contributing to death. The authors examined the incidence of major bleeding in patients with low-risk assignment by the systems of Ruiz-Gimenez et al. (score = 0 to 1), Beyth et al. (score = 0), Kuijer et al. (score = 0), and Landefeld and Goldman. (score = 0). For clinical relevance, the definition of low risk for all scores except Kuijer includes all patients < 65 years with no prior bleeding history and no comorbid conditions (current cancer, renal insufficiency, diabetes mellitus, anemia, prior stroke, or myocardial infarction)., Results: A total of 4,130 patients (1,731 with DVT only, 2,399 with PE with or without DVT) were treated with rivaroxaban for a mean (±SD) duration of 207.6 (±95.9) days. Major bleeding occurred in 1.0% (40 of 4,130; 95% confidence interval [CI] = 0.7% to 1.3%) overall. Rates of major bleeding for low-risk patients during the entire treatment period were similar: Ruiz-Gimenez et al., 12 of 2,622 (0.5%; 95% CI = 0.2% to 0.8%); Beyth et al., nine of 2,249 (0.4%; 95% CI = 0.2% to 0.8%); Kuijer et al., four of 1,186 (0.3%; 95% CI = 0.1% to 0.9%); and Landefeld and Goldman, 11 of 2,407 (0.5%; 95% CI = 0.2% to 0.8%). At 30 days, major bleed rates for low-risk patients were as follows: Ruiz-Gimenez et al., five of 2,622 (0.2%; 95% CI = 0.1% to 0.4%); Beyth et al., five of 2,249 (0.2%; 95% CI = 0.1% to 0.5%); Kuijer et al., three of 1,186 (0.3%; 95% CI = 0.1% to 0.7%); and Landefeld and Goldman, seven of 2,407 (0.3%; 95% CI = 0.1% to 0.6%). No low-risk patient had a fatal bleed., Conclusions: Four scoring systems that use criteria obtained in routine clinical practice, derived to predict low bleeding risk with VKA treatment for VTE, identified patients with less than a 1% risk of major bleeding during full-course treatment with rivaroxaban., (© 2016 by the Society for Academic Emergency Medicine.)

Vitamin K antagonists (VKA) are used to prevent recurrent disease in patients with venous thromboembolism (VTE). Their efficacy and safety depend on individual time in therapeutic range (iTTR) and variability of International Normalised Ratios (INR). We aimed to identify independent predictors of poor VKA control > 28 days. In a prospective cohort of 3825 VTE patients, separate logistic regression analyses were performed to identify predictors of low iTTR (first quartile) and instability (iTTR median). Subsequently, the association between these predictors and clinical outcomes was investigated. Weight < 50 kg (odds ratio [OR]=1.89; 95 % confidence interval [CI] 1.03-3.49), active cancer at baseline (OR=1.52; CI1.05-2.19), secondary VTE (OR=1.42; CI1.20-1.68), and INR < 2.0 at stop of double therapy (OR=1.35; CI1.09-1.67) were independent predictors of low iTTR. The first two were also predictive for instability (OR=1.96; CI1.06-3.63 and OR=1.95; CI1.36-2.80, respectively). ORs of early (≤ 28 days) low iTTR and instability depended on VKA type. In acenocoumarol users, early low iTTR was an independent predictor of subsequent low iTTR (OR=1.92; CI1.31-2.80) and instability (OR=1.55; CI1.07-2.23). In warfarin users, early low iTTR (OR=1.36; CI1.09-1.69) and instability (OR=1.25; CI1.01-1.55) were additionally predictive for low iTTR, but only the latter was predictive for instability (OR=1.91; CI1.57-2.32). Many predictors of VKA control also predicted premature discontinuation, but only region was prognostic for clinical outcome. In conclusion, we identified several independent predictors of low iTTR and instability > 28 days, which showed some similarities but did not fully overlap. Early VKA control was of additional value for prediction of both, but had to be interpreted in the context of VKA type.

Background: Rivaroxaban is a new oral anticoagulant (NOAC) that can be prescribed in a fixed dose, making regular monitoring and dose adjustments unnecessary. It has been proven to be safe and effective in comparison with enoxaparin/vitamin K antagonists (LMWH/VKA) for the (extended) treatment of venous thromboembolism in the EINSTEIN studies. Nevertheless, there is a need for information regarding the clinical impact of (major) bleeding events with NOACs such as rivaroxaban., Objectives: A post-hoc analysis was performed to compare the severity of clinical presentation and subsequent clinical course of major bleeding with rivaroxaban vs. LMWH/VKA., Methods: Two investigators performed a blinded classification of major bleeding using a priori defined criteria. During the EINSTEIN studies, data concerning the clinical course and measures applied were prospectively collected for each major bleed., Results: Treatment with LMWH/VKA caused more major bleeding events (1.7%) than rivaroxaban (1.0%; hazard ratio, 0.54; 95% confidence interval [CI], 0.37-0.79). Major bleeding events during rivaroxaban therapy had a milder presentation (23% were adjudicated to the worst categories vs. 38% for LMWH/VKA; hazard ratio or HR, 0.35; 95% CI, 0.17-0.74; P = 0.0062). The clinical course was severe in 25% of all major bleeding events associated with rivaroxaban, compared with 33% of LMWH/VKA-associated bleeds (HR, 0.46; 95% CI, 0.22-0.96; P = 0.040)., Conclusions: Rivaroxaban-associated major bleeding events occurred less frequently, had a milder presentation and appeared to take a less severe clinical course compared with major bleeding with LMWH/VKA., (© 2015 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.)

Patients with unprovoked venous thromboembolism (VTE) are at high risk for recurrence. Although rivaroxaban is effective for extended VTE treatment at a dose of 20 mg once daily, use of the 10 mg dose may further improve its benefit-to-risk ratio. Low-dose aspirin also reduces rates of recurrent VTE, but has not been compared with anticoagulant therapy. The EINSTEIN CHOICE study is a multicentre, randomised, double-blind, active-controlled, event-driven study comparing the efficacy and safety of two once daily doses of rivaroxaban (20 and 10 mg) with aspirin (100 mg daily) for the prevention of recurrent VTE in patients who completed 6-12 months of anticoagulant therapy for their index acute VTE event. All treatments will be given for 12 months. The primary efficacy objective is to determine whether both doses of rivaroxaban are superior to aspirin for the prevention of symptomatic recurrent VTE, while the principal safety outcome is the incidence of major bleeding. The trial is anticipated to enrol 2,850 patients from 230 sites in 31 countries over a period of 27 months. In conclusion, the EINSTEIN CHOICE study will provide new insights into the optimal antithrombotic strategy for extended VTE treatment by comparing two doses of rivaroxaban with aspirin (clinicaltrials.gov NCT02064439).

Background: In Japan, the standard of care for the treatment of pulmonary embolism (PE) and/or deep vein thrombosis (DVT) consists of intravenous unfractionated heparin (UFH) followed by warfarin, which was recently compared with rivaroxaban, an oral factor Xa inhibitor, in randomized trials., Aim: To examine the length of hospital stay in patients with PE and/or DVT receiving rivaroxaban compared to Japanese standard therapy in the Japanese (J)-EINSTEIN PE and DVT program., Methods: Open-label, randomized clinical trials that compared 3, 6, or 12 months of rivaroxaban with UFH and warfarin in patients with acute, confirmed symptomatic proximal PE and/or DVT. Decisions regarding hospital admission and/or discharge were left to the clinical judgment of attending physicians. Analyses were conducted in the intention-to-treat (ITT) population., Results: In the ITT population (N = 97), overall patient characteristics were similar in both treatment arms. The median length of stay in rivaroxaban patients was 10.0 days (interquartile range [IQR] 6.0 to 15.0 days) while it was 15.0 days (IQR 9.0 to 22.0) for patients on standard therapy (p = 0.016). All of the four DVT patients who were not hospitalized for the index event were in the rivaroxaban arm., Conclusions: Our results suggest that treatment with rivaroxaban may significantly reduce the length of hospital stay in patients hospitalized for PE and/or DVT compared with the current standard of care in Japan, thereby reducing the burden on patients and the healthcare system. The limitations of our study include small sample size and the generalizability of the findings to the real-world setting. Further research is warranted to identify PE and/or DVT patients in Japanese clinical practice who may potentially be managed as outpatients., Trial Registration: Clinicaltrials.gov: NCT01516814 and NCT01516840.

The impact of residual vein thrombosis (RVT) on the long-term outcome of patients with deep vein thrombosis (DVT) is unknown. We assessed the incidence of recurrent venous thromboembolism (VTE), postthrombotic syndrome (PTS), arterial thrombotic events, and cancer in patients with DVT with and without RVT. For this purpose, we evaluated up to 3 years 869 consecutive patients with acute proximal DVT who had conventional anticoagulation. RVT, defined as ultrasound incompressibility of at least 4 mm in the common femoral and/or the popliteal vein after 3 months, was detected in 429 (49.4%) patients, and was more likely in males (adjusted odds ratio [OR], 1.82; 95% confidence interval [CI], 1.37-2.04), in patients with previous VTE (OR, 1.64; 95% CI, 1.06-2.54), and in those with extensive thrombosis (OR, 3.58; 95% CI, 2.19-5.86). During the 3-year follow-up, recurrent VTE developed in 84 (19.6%) patients with RVT and 43 (9.8%) patients without RVT (adjusted hazard ratio [HR], 2.03; 95% CI, 1.40-2.94); PTS in 225 (52.4%) and 118 (26.8%), respectively (HR, 2.34; 95% CI, 1.87-2.93); arterial thrombosis in 29 (6.7%) and 14 (3.2%), respectively (HR, 2.05; 95% CI, 1.08-3.88); and cancer in 21 (4.9%) and 8 (1.8%), respectively (HR, 3.09; 95% CI, 1.31-7.28). In conclusion, in patients treated with vitamin K antagonists for prevention of recurrent VTE, RVT doubles the risk of recurrent VTE, PTS, arterial thrombosis, and cancer. Males, patients with previous VTE, and those with extensive thrombosis are independent risk factors of RVT development. Studies addressing the impact of the novel direct anticoagulants on the development of RVT as well as the long-term complications of DVT are needed., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Objectives: The objective was to assess adverse outcomes in relation to the simplified Pulmonary Embolism Severity Index (PESI) score in patients treated with rivaroxaban or standard therapy in the phase III EINSTEIN PE study and to evaluate the utility of the simplified PESI score to identify low-risk pulmonary embolism (PE) patients., Methods: A post hoc analysis of EINSTEIN PE data was performed to assess the efficacy and safety of rivaroxaban in patients with a range of simplified PESI scores. Recurrent venous thromboembolism, fatal PE, all-cause mortality, and major bleeding were stratified by simplified PESI scores of 0, 1, or ≥2 and according to treatment period at 7, 14, 30, and 90 days and at the end of the full intended treatment period., Results: Simplified PESI scores could be calculated in 4,831 of the 4,832 randomized patients; of those, 53.6, 36.7, and 9.7% had PESI scores of 0, 1, and ≥2, respectively. Among patients with simplified PESI scores of 0 or 1, fatal PE, all-cause mortality, and other adverse outcomes were uncommon within the first 7, 14, and 30 days. Patients with simplified PESI scores of ≥2 had more frequent adverse outcomes. Major bleeding was lower in the rivaroxaban group, particularly in those with simplified PESI scores of 1 or ≥2., Conclusions: The findings support using risk stratification with the simplified PESI score to identify low-risk patients with PE., (© 2015 The Authors. Academic Emergency Medicine published by Wiley Periodicals, Inc. on behalf of Society for Acadamic Emergency Medicine.)

Introduction: Rivaroxaban is an oral, direct Factor Xa inhibitor, approved for the treatment of pulmonary embolism (PE) and deep vein thrombosis (DVT) and the secondary prevention of recurrent PE and DVT as a fixed-dose, monotherapy regimen that does not require initial heparinisation, routine coagulation monitoring or dose adjustment. Approval in this indication was supported by results from EINSTEIN PE, a large, randomised, open-label study that compared rivaroxaban with enoxaparin/vitamin K antagonist (VKA) therapy in patients with acute symptomatic PE with or without DVT., Materials and Methods: Patient-reported treatment satisfaction was evaluated in a predefined subanalysis of EINSTEIN PE to enable monitoring and optimisation of patient-reported outcomes and, therefore, patient compliance. As part of EINSTEIN PE, 2,397 patients in seven countries were asked to complete a validated measure of treatment satisfaction, the Anti-Clot Treatment Scale (ACTS) throughout the duration of treatment (up to 12 months)., Results: Patients reported greater satisfaction in the rivaroxaban treatment arm as compared with the enoxaparin/VKA treatment arm. Treatment with rivaroxaban was reported as being significantly less burdensome than enoxaparin/VKA therapy, and the benefits of treatment were significantly greater., Conclusion: Rivaroxaban treatment resulted in improved treatment satisfaction compared with enoxaparin/VKA in PE patients, particularly in reducing patient-reported anticoagulation burden., (Copyright © 2014. Published by Elsevier Ltd.)

Objectives: In the EINSTEIN DVT and EINSTEIN PE studies, the majority of patients received heparins to bridge the period during venous thromboembolism (VTE) diagnosis confirmation and the start of the study. In contrast to vitamin K antagonists (VKAs), rivaroxaban may not require initial heparin treatment., Methods: To evaluate the effect of prestudy heparin on the efficacy and safety of rivaroxaban relative to enoxaparin/VKA, the 3-month incidence of recurrent VTE, and the 14-day incidence of major and nonmajor clinically relevant bleeding were compared in patients who did and did not receive prestudy heparin., Results: Of the 8,281 patients randomized, 6,937 (83.8%) received prestudy heparin (mean ± SD duration = rivaroxaban: 1.04 [± 0.74] days; enoxaparin 1.03 [± 0.42] days), and 1,344 (16.2%) did not. In patients who did not receive prestudy heparin, the incidences of recurrent VTE were similar in rivaroxaban (15 of 649, 2.3%) and enoxaparin/VKA (13 of 695, 1.9%) patients (adjusted hazard ratio [HR] = 1.11; 95% confidence interval [CI] = 0.52 to 2.37). The incidences of recurrent VTE were also similar in rivaroxaban (54 of 3,501, 1.5%) and enoxaparin/VKA (69 of 3,436, 2.0%) patients who did receive prestudy heparin (adjusted HR = 0.74; 95% CI = 0.52 to 1.06; pinteraction  = 0.32). The incidences of major or nonmajor clinically relevant bleeding with rivaroxaban were not significantly different from those with enoxaparin/VKA, either with (105 of 3,485, 3.0% vs. 104 of 3,428, 3.0%; adjusted HR = 0.98; 95% CI = 0.75 to 1.29) or without (24 of 645, 3.7% vs. 30 of 688, 4.4%; adjusted HR = 0.81; 95% CI = 0.46 to 1.40; pinteraction  = 0.68) prestudy heparin., Conclusions: Although the majority of patients in the EINSTEIN studies received prestudy heparin, there were no notable differences in treatment effect of rivaroxaban versus enoxaparin/VKA in those who did and did not receive it., (© 2015 by the Society for Academic Emergency Medicine.)

Background: The global EINSTEIN DVT and PE studies compared rivaroxaban (15 mg twice daily for 3 weeks followed by 20 mg once daily) with enoxaparin/vitamin K antagonist therapy and demonstrated non-inferiority for efficacy and superiority for major bleeding. Owing to differences in targeted anticoagulant intensities in Japan, Japanese patients were not enrolled into the global studies. Instead, a separate study of deep vein thrombosis (DVT) and/or pulmonary embolism (PE) in Japanese patients was conducted, which compared the Japanese standard of care with a reduced dose of rivaroxaban., Methods: We conducted an open-label, randomized trial that compared 3, 6, or 12 months of oral rivaroxaban alone (10 mg twice daily or 15 mg twice daily for 3 weeks followed by 15 mg once daily) with activated partial thromboplastin time-adjusted intravenous unfractionated heparin (UFH) followed by warfarin (target international normalized ratio 2.0; range 1.5-2.5) in patients with acute, objectively confirmed symptomatic DVT and/or PE. Patients were assessed for the occurrence of symptomatic recurrent venous thromboembolic events or asymptomatic deterioration and bleeding., Results: Eighty-one patients were assigned to rivaroxaban and 19 patients to UFH/warfarin. Three patients were excluded because of serious non-compliance issues. The composite of symptomatic venous thromboembolic events or asymptomatic deterioration occurred in 1 (1.4%) rivaroxaban patient and in 1 (5.3%) UFH/warfarin patient (absolute risk difference, 3.9% [95% confidence interval, -3.4-23.8]). No major bleeding occurred during study treatment. Clinically relevant non-major bleeding occurred in 6 (7.8%) patients in the rivaroxaban group and 1 (5.3%) patient in the UFH/warfarin group., Conclusions: The findings of this study in Japanese patients with acute DVT and/or PE suggest a similar efficacy and safety profile with rivaroxaban and control treatment, consistent with that of the worldwide EINSTEIN DVT and PE program., Trial Registration: Clinicaltrials.gov: NCT01516840 and NCT01516814.

Background: Statins may reduce the risk of first and recurrent venous thromboembolism (VTE). No data are available on their potential benefit in patients treated with the oral anticoagulant rivaroxaban., Methods: The EINSTEIN DVT/PE and EINSTEIN Extension studies compared rivaroxaban with standard of care (n=8280) and placebo (n=1188), respectively. The incidences of recurrent VTE and major bleeding per 100 patient-years for exposure (or not) to statins were calculated. A Cox proportional hazards model was constructed, stratified by index event and intended treatment duration, with statin use as a time-dependent variable, for each treatment group (rivaroxaban vs enoxaparin/vitamin K antagonist or placebo) and adjusted for relevant variables., Results: In EINSTEIN DVT/PE, 1509 (18.3%) patients used statins during the at-risk period, and 6731 (81.7%) did not. Overall, 2.6 recurrent VTEs occurred per 100 patient-years with statin use compared with 3.8 per 100 patient-years without statins (adjusted hazard ratio [HR] 0.76; 95% confidence interval [CI] 0.46-1.25). HRs for recurrent VTE were similar for concomitant use of rivaroxaban-statin and enoxaparin/VKA-statin. Major bleeding events occurred in 3.0 per 100 patient-years with statin use compared with 2.3 per 100 patient-years without statins (adjusted HR 0.77; 95% CI 0.46-1.29). Due to adjustments in the Cox regression model, the direction of this HR is in contrast to the crude comparison. In EINSTEIN Extension, no recurrent VTEs occurred with statin use in the rivaroxaban group compared with 1.6 per 100 patient-years without statins. In the placebo group, 12.2 recurrent VTEs occurred per 100 patient-years with statin use compared with 13.2 per 100 patient-years without (adjusted HR 0.81; 95% CI 0.35-1.86)., Conclusions: The effect of statins in this secondary analysis of the EINSTEIN VTE treatment program is consistent with other studies that suggest a reduced risk of recurrent VTE, but conclusive evidence of this benefit is lacking. Statins are simple to use, inexpensive, very safe and do not cause bleeding. Therefore, the potential effect on reducing recurrent VTE, which is in the range of that of acetylsalicylic acid, deserves evaluation in a large randomized trial., Trial Registration Number: ClinicalTrials.gov: EINSTEIN PE, NCT00439777; EINSTEIN DVT, NCT00440193; EINSTEIN Extension, NCT00439725.

Background: Patients with renal impairment receiving classical anticoagulation for venous thromboembolism (VTE) are at increased risk of bleeding and possibly pulmonary embolism. We examined the efficacy and safety of oral rivaroxaban in patients with VTE with and without renal impairment., Methods: Prespecified subgroup analysis of the EINSTEIN DVT and EINSTEIN PE studies comparing fixed-dose rivaroxaban with enoxaparin/a vitamin K antagonist (VKA), performed in 8246 patients enrolled from 2007 to 2011 in 314 hospitals., Results: Outcomes were recurrent VTE and major or clinically relevant nonmajor bleeding in patients with normal renal function (n = 5569; 67.3%) or mild (n = 2037; 24.6%), moderate (n = 636; 7.7%), or severe (n = 21; 0.3%) renal impairment. Rates of recurrent VTE were 1.8%, 2.8%, 3.3%, and 4.8% in patients with normal renal function and mild, moderate, and severe renal impairment, respectively (ptrend = 0.001). Hazard ratios for recurrent VTE were similar between treatment groups across renal function categories (pinteraction = 0.72). Major bleeding in rivaroxaban recipients occurred in 0.8%, 1.4%, 0.9%, and 0%, respectively (ptrend = 0.50). Respective rates in enoxaparin/VKA recipients were 1.0%, 3.0%, 3.9%, and 9.1% (ptrend < 0.001). Rivaroxaban-enoxaparin/VKA hazard ratios were 0.79 (95% confidence interval [CI] 0.46-1.36) for normal renal function, 0.44 (95% CI 0.24-0.84) for mild renal impairment, and 0.23 (95% CI 0.06-0.81) for moderate renal impairment (pinteraction = 0.034)., Conclusions: Patients with symptomatic VTE and renal impairment are at increased risk of recurrent VTE. Renal impairment increased the risk of major bleeding in enoxaparin/VKA-treated patients but not in rivaroxaban-treated patients., Trial Registration: NCT00440193 and NCT00439777.

Background: Patients with venous thromboembolism and cancer have a substantial risk of recurrent venous thromboembolism and bleeding during anticoagulant therapy. Although monotherapy with low-molecular-weight heparin is recommended in these patients, in clinical practice many patients with venous thromboembolism and cancer do not receive this treatment. We aimed to assess the efficacy and safety of a single-drug regimen with oral rivaroxaban compared with enoxaparin followed by vitamin K antagonists, in the subgroup of patients with cancer enrolled in the EINSTEIN-DVT and EINSTEIN-PE randomised controlled trials., Methods: We did a subgroup analysis of patients with active cancer (either at baseline or diagnosed during the study), a history of cancer, or no cancer who were enrolled in the EINSTEIN-DVT and EINSTEIN-PE trials. Eligible patients with deep-vein thrombosis (EINSTEIN-DVT) or pulmonary embolism (EINSTEIN-PE) were randomly assigned in a 1:1 ratio to receive rivaroxaban (15 mg twice daily for 21 days, followed by 20 mg once daily) or standard therapy (enoxaparin 1·0 mg/kg twice daily and warfarin or acenocoumarol; international normalised ratio 2·0-3·0). Randomisation with a computerised voice-response system was stratified according to country and intended treatment duration (3, 6, or 12 months). The prespecified primary efficacy and safety outcomes of both the trials and this subanalysis were symptomatic recurrent venous thromboembolism and clinically relevant bleeding, respectively. We did efficacy and mortality analyses in the intention-to-treat population, and bleeding analyses for time spent receiving treatment plus 2 days in the safety population (all patients who received at least one dose of study drug). The EINSTEIN-DVT and EINSTEIN-PE studies are registered at ClinicalTrials.gov, numbers NCT00440193 and NCT00439777., Findings: In patients with active cancer (diagnosed at baseline or during treatment), recurrent venous thromboembolism occurred in 16 (5%) of 354 patients allocated to rivaroxaban and 20 (7%) of 301 patients allocated to enoxaparin and vitamin K antagonist (hazard ratio [HR] 0·67, 95% CI 0·35 to 1·30). Clinically relevant bleeding occurred in 48 (14%) of 353 patients receiving rivaroxaban and in 49 (16%) of 298 patients receiving standard therapy (HR 0·80, 95% CI 0·54 to 1·20). Major bleeding occurred in eight (2%) of 353 patients receiving rivaroxaban and in 15 (5%) of 298 patients receiving standard therapy (HR 0·42, 95% CI 0·18 to 0·99). The overall frequency of recurrent venous thromboembolism in patients with only a history of cancer (five [2%] of 233 patients in the rivaroxaban group vs five [2%] of 236 in the standard therapy group; HR 0·98, 95% CI 0·28-3·43) was similar to that of patients without cancer (65 [2%] of 3563 vs 70 [2%] of 3594, respectively; HR 0·93, 95% CI 0·66-1·30), but the frequency was increased in patients with active cancer at baseline (six [2%] of 258 vs eight [4%] of 204, respectively; HR 0·62, 95% CI 0·21-1·79) and most markedly increased in patients whose diagnosis of cancer was made during the study (ten [10%] of 96 vs 12 [12%] of 97, respectively; HR 0·80, 95% CI 0·34-1·88). The overall frequency of major bleeding in patients with only a history of cancer (one [<1%] patient in the rivaroxaban group vs four [2%] patients in the standard therapy group; HR 0·23, 95% CI 0·03-2·06) was similar to that of patients without cancer (31 [1%] vs 53 [1%], respectively; HR 0·58, 95% CI 0·37-0·91), but was increased in patients with active cancer at baseline (five [2%] vs eight [4%], respectively; HR 0·47, 95% CI 0·15-1·45) and was highest in those with cancer diagnosed during the study (three [3%] vs seven [7%], respectively; HR 0·33, 95% CI 0·08-1·31)., Interpretation: In patients with active cancer and venous thromboembolism, rivaroxaban had similar efficacy to prevent recurrence of venous thromboembolism and reduced the number major bleeding events compared with treatment with enoxaparin and a vitamin K antagonist, although there was no difference between groups for clinically relevant bleeding. Based on these results, a head-to-head comparison of rivaroxaban with long-term low-molecular-weight heparin in patients with cancer is warranted., Funding: Bayer HealthCare Pharmaceuticals and Janssen Research & Development., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Importance: Combined anticoagulant and aspirin therapy is associated with increased bleeding risk in patients with atrial fibrillation, but the bleeding risk of combined use of anticoagulant and nonsteroidal anti-inflammatory drugs (NSAIDs) is poorly documented., Objective: To estimate the bleeding risk of combined anticoagulant (rivaroxaban or enoxaparin-vitamin K antagonist [VKA]) and NSAID or aspirin therapy in patients with venous thromboembolism., Design, Setting, and Participants: Prospective analysis of observational data from the EINSTEIN deep vein thrombosis and pulmonary embolism clinical trials comparing rivaroxaban with enoxaparin-VKA treatment, trials performed in hospitals and clinics in 8246 patients enrolled from 2007 to 2009., Exposure: Bleeding event rates during exposure to NSAID and aspirin therapy were compared to time without exposure., Main Outcomes and Measures: Days of NSAID or aspirin use and nonuse, clinically relevant bleeding event and major bleeding event rates by patient-years, and hazard ratios., Results: During NSAID-anticoagulant concomitant treatment, clinically relevant bleeding occurred with an event rate of 37.5 per 100 patient-years vs 16.6 per 100 patient-years during anticoagulant use only (hazard ratio [HR], 1.77 [95% CI, 1.46-2.14]). Major bleeding during NSAID-anticoagulant treatment occurred with an event rate of 6.5 per 100 patient-years, compared to 2.0 per 100 patient-years during nonuse (HR, 2.37 [95% CI, 1.51-3.75]). For aspirin-anticoagulant concomitant treatment, clinically relevant bleeding occurred with an event rate of 36.6 per 100 patient-years, compared to 16.9 per 100 patient-years during aspirin nonuse (HR, 1.70 [95% CI, 1.38-2.11]). Major bleeding in aspirin-anticoagulant-treated patients occurred with an event rate of 4.8 per 100 patient-years, compared to 2.2 per 100 patient-years during aspirin nonuse (HR, 1.50 [95% CI, 0.86-2.62]). Increases in risk for clinically relevant and major bleeding were similar for rivaroxaban and enoxaparin-VKA anticoagulation regimens., Conclusions and Relevance: Among patients with venous thromboembolism receiving anticoagulant therapy, concomitant use of an NSAID or aspirin is associated with an increased risk of clinically relevant and major bleeding.

Objective: The phase III EINSTEIN DVT and EINSTEIN PE trials demonstrated the potential of oral rivaroxaban for the treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE). The length of initial hospitalization in patients presenting with either symptomatic DVT or PE was assessed using hospitalization records from these trials., Methods: Analyses were carried out in the intention-to-treat population, using non-parametric and parametric statistical methods., Results: Overall, 52% (1781/3434) of EINSTEIN DVT patients and 90% (4328/4821) of EINSTEIN PE patients were admitted to hospital. The proportion of hospitalized patients with a length of stay of five or fewer days receiving rivaroxaban was 54% compared with 31% for enoxaparin/vitamin K antagonist (VKA) in patients with DVT. For patients with PE, the corresponding values were 45% and 33%. Stays of 6-10 days were observed in 29% of rivaroxaban-treated patients compared with 45% of enoxaparin/VKA-treated patients for DVT. For patients with PE, these values were 39% and 46% in the rivaroxaban and enoxaparin/VKA groups, respectively. Overall, length of stay was significantly shorter in the rivaroxaban group, compared with the enoxaparin/VKA group across all analyses performed (p < 0.0001). Across regions, the observed admission rates and length of stay duration varied greatly: Asia had the longest overall hospitalization rates, whereas the lowest rates were reported in North America, Australia and New Zealand. Nevertheless, a consistent trend was observed: length of hospital stay in patients with DVT or PE receiving rivaroxaban was shorter than, or at least similar to, patients receiving enoxaparin/VKA., Conclusion: A single-drug regimen with rivaroxaban may reduce the burden on healthcare systems and patients, and provides effective and well tolerated treatment. The studies shared an open-label design that allowed comparison of initial hospitalization, but limitations include the well monitored clinical trial setting in which decisions on admission and discharge could vary from real-world management.

Background: The worldwide EINSTEIN DVT and EINSTEIN PE studies randomized 8282 patients with acute symptomatic deep-vein thrombosis (DVT) and/or pulmonary embolism (PE) and, for the first time in trials in this setting, included patients in China. This analysis evaluates the results of these studies in this subgroup of patients., Methods: A total of 439 Chinese patients who had acute symptomatic DVT (n=211), or PE with or without DVT (n=228), were randomized to receive rivaroxaban (15 mg twice daily for 21 days, followed by 20 mg once daily) or standard therapy of enoxaparin overlapping with and followed by an adjusted-dose vitamin K antagonist, for 3, 6, or 12 months. The primary efficacy outcome was symptomatic recurrent venous thromboembolism. The principal safety outcome was major or non-major clinically relevant bleeding., Results: The primary efficacy outcome occurred in seven (3.2%) of the 220 patients in the rivaroxaban group and in seven (3.2%) of the 219 patients in the standard-therapy group (hazard ratio, 1.04; 95% confidence interval 0.36-3.0; p=0.94). The principal safety outcome occurred in 13 (5.9%) patients in the rivaroxaban group and in 20 (9.2%) patients in the standard-therapy group (hazard ratio, 0.63; 95% confidence interval 0.31-1.26; p=0.19). Major bleeding was observed in no patients in the rivaroxaban group and in five (2.3%) patients in the standard-therapy group. In fragile patients (defined as age >75 years, creatinine clearance <50 mL/min, and/or body weight ≤50 kg), the principal safety outcome occurred in four (8.9%) of the 45 patients who received rivaroxaban compared with seven (15.2%) of the 46 patients who received standard therapy., Conclusions: In Chinese patients with acute symptomatic DVT and/or PE, rivaroxaban was as efficacious as enoxaparin followed by vitamin K antagonist therapy, with a similar safety profile. The relative efficacy and safety of rivaroxaban compared with enoxaparin/vitamin K antagonist were consistent with that found in the rest of the world., Trial Registration Number: EINSTEIN PE, ClinicalTrials.gov NCT00439777; EINSTEIN DVT, ClinicalTrials.gov NCT00440193.

Rivaroxaban, an oral, direct factor Xa inhibitor, has been approved for the treatment of deep-vein thrombosis (DVT) and pulmonary embolism (PE) and the prevention of recurrent DVT and PE as a fixed-dose, single-drug regimen that does not require initial heparinisation, routine coagulation monitoring or dose adjustment. This study evaluated patient-reported treatment satisfaction in EINSTEIN DVT--a large, open-label, randomised study that compared rivaroxaban with enoxaparin/vitamin K antagonist (VKA) therapy in patients with acute symptomatic DVT without PE. As part of EINSTEIN DVT, a total of 1,472 patients in seven countries were asked to complete a new, validated measure of treatment satisfaction--the Anti-Clot Treatment Scale (ACTS)--at scheduled visits throughout 12 months of treatment. ACTS scores were compared between study groups in the intention-to-treat population. Patients reported greater satisfaction in the rivaroxaban group compared with the enoxaparin/VKA group, with higher mean ACTS scores across visits. Mean ACTS Burdens scores were 55.2 vs 52.6 (p<0.0001) in favour of rivaroxaban, equivalent to a moderate effect size of 0.42. The treatment effect was consistent over time, with the mean score difference ranging from 2.18 (month 2) to 3.18 (month 12). Overall mean ACTS Benefits scores were 11.7 vs 11.5 in favour of rivaroxaban (p=0.006). This was associated with a small overall effect size of 0.12. The improvement in ACTS Benefits for rivaroxaban became apparent at month 2 and subsequent visits. Rivaroxaban results in improved treatment satisfaction compared with enoxaparin/VKA among patients with DVT, particularly in reducing patient-reported anticoagulation burden.

Background: Standard treatment for venous thromboembolism (VTE) consists of a heparin combined with vitamin K antagonists. Direct oral anticoagulants have been investigated for acute and extended treatment of symptomatic VTE; their use could avoid parenteral treatment and/or laboratory monitoring of anticoagulant effects., Methods: A prespecified pooled analysis of the EINSTEIN-DVT and EINSTEIN-PE studies compared the efficacy and safety of rivaroxaban (15 mg twice-daily for 21 days, followed by 20 mg once-daily) with standard-therapy (enoxaparin 1.0 mg/kg twice-daily and warfarin or acenocoumarol). Patients were treated for 3, 6, or 12 months and followed for suspected recurrent VTE and bleeding. The prespecified noninferiority margin was 1.75., Results: A total of 8282 patients were enrolled; 4151 received rivaroxaban and 4131 received standard-therapy. The primary efficacy outcome occurred in 86 (2.1%) rivaroxaban-treated patients compared with 95 (2.3%) standard-therapy-treated patients (hazard ratio, 0.89; 95% confidence interval [CI], 0.66-1.19; pnoninferiority < 0.001). Major bleeding was observed in 40 (1.0%) and 72 (1.7%) patients in the rivaroxaban and standard-therapy groups, respectively (hazard ratio, 0.54; 95% CI, 0.37-0.79; p = 0.002). In key subgroups, including fragile patients, cancer patients, patients presenting with large clots, and those with a history of recurrent VTE, the efficacy and safety of rivaroxaban were similar compared with standard-therapy., Conclusion: The single-drug approach with rivaroxaban resulted in similar efficacy to standard-therapy and was associated with a significantly lower rate of major bleeding. Efficacy and safety results were consistent among key patient subgroups., Trial Registration Einstein-Pe: ClinicalTrials.gov, NCT00439777; EINSTEIN-DVT: ClinicalTrials.gov, NCT00440193.

Background: Direct oral anticoagulants that target a single coagulation factor have been developed as an alternative to standard therapies with heparin and/or vitamin K antagonists. The purpose of this study was to derive non-inferiority margins suitable for randomised clinical studies designed to evaluate these agents for the treatment of venous thromboembolism (VTE)., Methods: We performed a systematic review to derive non-inferiority margins suitable for use in studies evaluating direct oral anticoagulants for the treatment of VTE. A PubMed search identified publications that evaluated current standard treatment versus placebo, 'no treatment' or 'less intensive treatment' in patients with symptomatic deep vein thrombosis (DVT) and/or pulmonary embolism (PE). Publications were eligible if they had a randomised study design, included patients with symptomatic DVT and/or PE, used objective diagnostic methods to document the index event and reported objectively confirmed symptomatic recurrent VTE., Results: Fourteen publications were included in the analysis. Recurrent VTE occurred in 25 (1.5%) out of 1715 patients who received current standard of care and in 157 (9.2%) out of 1711 patients who received placebo, 'no treatment' or 'less intensive treatment', for an odds ratio of 0.18 (95% confidence interval, 0.14-0.25; test for heterogeneity, p=0.87). In order to preserve 50% or 75% of the established treatment effect using a linear scale, the corresponding thresholds for non-inferiority equalled 2.50 and 1.75, respectively., Conclusions: This systematic review and statistical approach determined non-inferiority margins suitable for use in studies of direct oral anticoagulants for the treatment of DVT and/or PE.

The development of rivaroxaban (XARELTO®) is an important new medical advance in the field of oral anticoagulation. Thrombosis-mediated conditions constitute a major burden for patients, healthcare systems, and society. For more than 60 years, the prevention and treatment of these conditions have been dominated by oral vitamin K antagonists (such as warfarin) and the injectable heparins. Thrombosis can lead to several conditions, including deep vein thrombosis, pulmonary embolism, myocardial infarction, stroke, and/or death. Prevention and treatment of thrombosis with an effective, convenient-to-use oral anticoagulant with a favorable safety profile is critical, especially in an aging society in which the risk of thrombosis, and the potential for bleeding complications, is increasing. Rivaroxaban acts to prevent and treat thrombosis by potently inhibiting coagulation Factor Xa in the blood. Factor Xa converts prothrombin to thrombin, which initiates the formation of blood clots by converting fibrinogen to clot-forming fibrin and leads to platelet activation. After a large and novel clinical development program in over 75,000 patients to date, rivaroxaban has received approval for multiple indications in the United States, European Union, and other countries worldwide to prevent and treat several thrombosis-mediated conditions. This review will highlight some of the unique aspects of the rivaroxaban development program., (© 2013 New York Academy of Sciences.)

Introduction: Little is known about the natural history of clot resolution in the initial weeks of anticoagulant therapy in patients with acute pulmonary embolism (PE). Clot resolution of acute PE was assessed with either computed tomography pulmonary angiography scan (CT-scan) or perfusion scintigraphy scan (Q-scan) after 3 weeks of treatment., Methods: This was a predefined safety analysis of the Einstein PE study, including PE patients, randomized to either enoxaparin with vitamin K antagonist (VKA) or rivaroxaban. A similar scan as at baseline was repeated after 3 weeks. The percentage of vascular obstruction (PVO) was calculated on the basis of a weighted semiquantitative estimation of obstruction. Clot resolution was assessed blindly by calculating the relative change after 3 weeks., Results: PE was diagnosed in 264 patients with CT-scan and in 83 with Q-scan. Baseline characteristics were similar. At baseline, the mean PVO assessed with CT-scan (PVO-CT) and the mean PVO assessed with Q-scan (PVO-Q) were both 21% (standard deviation [SD] 13%) (P = 0.9). The mean relative decrease in PVO was 71% (SD 33%) for PVO-CT, and 62% (SD 36%) for PVO-Q (P = 0.02); complete resolution was observed in 44% (116/264; 95% confidence interval [CI] 38-50%) and 31% (26/83; 95% CI 22-42%) with CT-scan and Q-scan, respectively (P = 0.04). No difference in clot resolution between enoxaparin/VKA and rivaroxaban was found., Conclusion: In patients with acute PE, only 3 weeks of anticoagulant treatment leads to complete clot resolution in a considerable proportion of patients, and normalization is more often observed with CT-scan than with Q-scan., (© 2013 International Society on Thrombosis and Haemostasis.)

Stress-induced hyperglycaemia is common during orthopaedic surgery. In addition, hyperglycaemia activates coagulation. The aim of the study was to assess whether stress-induced hyperglycaemia is associated with symptomatic or asymptomatic venous thromboembolism (VTE) following orthopaedic surgery. We performed post-hoc analyses in the four RECORD studies (REgulation of Coagulation in major Orthopaedic surgery reducing the Risk of Deep venous thrombosis and pulmonary embolism). Separate analyses were performed for patients undergoing elective total hip or knee replacement. Outcome measures were symptomatic VTE and "total VTE" (defined as the composite of symptomatic VTE, asymptomatic DVT assessed by per protocol venography and all cause mortality). Glucose levels were measured pre-op and 6 hours post-op, categorised into quartiles, based on the distribution in the respective cohorts. The influence of glucose, adjusted for body mass index, age, gender and diabetes mellitus on VTE was assessed by logistic regression analyses. A total of 12,383 patients were eligible for assessment of symptomatic VTE, and 8,512 patients were eligible for assessment of total VTE. Increased glucose levels after total hip replacement were associated with total VTE; adjusted odds ratio (OR) highest versus lowest quartile 1.9 (95% confidence interval [CI] 1.3 to 3.0). Furthermore, increase in glucose levels during total hip replacement was associated with total VTE (OR highest versus lowest quartile 1.8 (95%CI 1.2 to 2.8). This was not observed in patients undergoing total knee replacement, probably due to differences in the applied surgical procedures.

Background: Rivaroxaban, an oral factor Xa inhibitor, may provide a simple, fixed-dose regimen for treating acute deep-vein thrombosis (DVT) and for continued treatment, without the need for laboratory monitoring., Methods: We conducted an open-label, randomized, event-driven, noninferiority study that compared oral rivaroxaban alone (15 mg twice daily for 3 weeks, followed by 20 mg once daily) with subcutaneous enoxaparin followed by a vitamin K antagonist (either warfarin or acenocoumarol) for 3, 6, or 12 months in patients with acute, symptomatic DVT. In parallel, we carried out a double-blind, randomized, event-driven superiority study that compared rivaroxaban alone (20 mg once daily) with placebo for an additional 6 or 12 months in patients who had completed 6 to 12 months of treatment for venous thromboembolism. The primary efficacy outcome for both studies was recurrent venous thromboembolism. The principal safety outcome was major bleeding or clinically relevant nonmajor bleeding in the initial-treatment study and major bleeding in the continued-treatment study., Results: The study of rivaroxaban for acute DVT included 3449 patients: 1731 given rivaroxaban and 1718 given enoxaparin plus a vitamin K antagonist. Rivaroxaban had noninferior efficacy with respect to the primary outcome (36 events [2.1%], vs. 51 events with enoxaparin-vitamin K antagonist [3.0%]; hazard ratio, 0.68; 95% confidence interval [CI], 0.44 to 1.04; P<0.001). The principal safety outcome occurred in 8.1% of the patients in each group. In the continued-treatment study, which included 602 patients in the rivaroxaban group and 594 in the placebo group, rivaroxaban had superior efficacy (8 events [1.3%], vs. 42 with placebo [7.1%]; hazard ratio, 0.18; 95% CI, 0.09 to 0.39; P<0.001). Four patients in the rivaroxaban group had nonfatal major bleeding (0.7%), versus none in the placebo group (P=0.11)., Conclusions: Rivaroxaban offers a simple, single-drug approach to the short-term and continued treatment of venous thrombosis that may improve the benefit-to-risk profile of anticoagulation. (Funded by Bayer Schering Pharma and Ortho-McNeil; ClinicalTrials.gov numbers, NCT00440193 and NCT00439725.).