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Concept: Anticoagulants

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Background Specific reversal agents for non-vitamin K antagonist oral anticoagulants are lacking. Idarucizumab, an antibody fragment, was developed to reverse the anticoagulant effects of dabigatran. Methods We undertook this prospective cohort study to determine the safety of 5 g of intravenous idarucizumab and its capacity to reverse the anticoagulant effects of dabigatran in patients who had serious bleeding (group A) or required an urgent procedure (group B). The primary end point was the maximum percentage reversal of the anticoagulant effect of dabigatran within 4 hours after the administration of idarucizumab, on the basis of the determination at a central laboratory of the dilute thrombin time or ecarin clotting time. A key secondary end point was the restoration of hemostasis. Results This interim analysis included 90 patients who received idarucizumab (51 patients in group A and 39 in group B). Among 68 patients with an elevated dilute thrombin time and 81 with an elevated ecarin clotting time at baseline, the median maximum percentage reversal was 100% (95% confidence interval, 100 to 100). Idarucizumab normalized the test results in 88 to 98% of the patients, an effect that was evident within minutes. Concentrations of unbound dabigatran remained below 20 ng per milliliter at 24 hours in 79% of the patients. Among 35 patients in group A who could be assessed, hemostasis, as determined by local investigators, was restored at a median of 11.4 hours. Among 36 patients in group B who underwent a procedure, normal intraoperative hemostasis was reported in 33, and mildly or moderately abnormal hemostasis was reported in 2 patients and 1 patient, respectively. One thrombotic event occurred within 72 hours after idarucizumab administration in a patient in whom anticoagulants had not been reinitiated. Conclusions Idarucizumab completely reversed the anticoagulant effect of dabigatran within minutes. (Funded by Boehringer Ingelheim; RE-VERSE AD ClinicalTrials.gov number, NCT02104947 .).

Concepts: Atrial fibrillation, Warfarin, Normal distribution, Anticoagulant, Heparin, Dabigatran, Anticoagulants, Direct thrombin inhibitor

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Background Catheter ablation of atrial fibrillation is typically performed with uninterrupted anticoagulation with warfarin or interrupted non-vitamin K antagonist oral anticoagulant therapy. Uninterrupted anticoagulation with a non-vitamin K antagonist oral anticoagulant, such as dabigatran, may be safer; however, controlled data are lacking. We investigated the safety of uninterrupted dabigatran versus warfarin in patients undergoing ablation of atrial fibrillation. Methods In this randomized, open-label, multicenter, controlled trial with blinded adjudicated end-point assessments, we randomly assigned patients scheduled for catheter ablation of paroxysmal or persistent atrial fibrillation to receive either dabigatran (150 mg twice daily) or warfarin (target international normalized ratio, 2.0 to 3.0). Ablation was performed after 4 to 8 weeks of uninterrupted anticoagulation, which was continued during and for 8 weeks after ablation. The primary end point was the incidence of major bleeding events during and up to 8 weeks after ablation; secondary end points included thromboembolic and other bleeding events. Results The trial enrolled 704 patients across 104 sites; 635 patients underwent ablation. Baseline characteristics were balanced between treatment groups. The incidence of major bleeding events during and up to 8 weeks after ablation was lower with dabigatran than with warfarin (5 patients [1.6%] vs. 22 patients [6.9%]; absolute risk difference, -5.3 percentage points; 95% confidence interval, -8.4 to -2.2; P<0.001). Dabigatran was associated with fewer periprocedural pericardial tamponades and groin hematomas than warfarin. The two treatment groups had a similar incidence of minor bleeding events. One thromboembolic event occurred in the warfarin group. Conclusions In patients undergoing ablation for atrial fibrillation, anticoagulation with uninterrupted dabigatran was associated with fewer bleeding complications than uninterrupted warfarin. (Funded by Boehringer Ingelheim; RE-CIRCUIT ClinicalTrials.gov number, NCT02348723 .).

Concepts: Medical statistics, Stroke, Atrial fibrillation, Warfarin, Anticoagulant, Heparin, Dabigatran, Anticoagulants

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Although non-vitamin K antagonist oral anticoagulants are recommended for stroke prevention in patients with non-valvular atrial fibrillation (NVAF) based on clinical trial results, there is a need for safety and efficacy data from unselected patients in everyday clinical practice. XANTUS investigated the safety and efficacy of the Factor Xa inhibitor rivaroxaban in routine clinical use in the NVAF setting.

Concepts: Clinical trial, Stroke, Atrial fibrillation, Warfarin, Anticoagulant, Heparin, Dabigatran, Anticoagulants

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Objective To determine the safety of direct oral anticoagulant (DOAC) use compared with warfarin use for the treatment of venous thromboembolism.Design Retrospective matched cohort study conducted between 1 January 2009 and 31 March 2016.Setting Community based, using healthcare data from six jurisdictions in Canada and the United States.Participants 59 525 adults (12 489 DOAC users; 47 036 warfarin users) with a new diagnosis of venous thromboembolism and a prescription for a DOAC or warfarin within 30 days of diagnosis.Main outcome measures Outcomes included hospital admission or emergency department visit for major bleeding and all cause mortality within 90 days after starting treatment. Propensity score matching and shared frailty models were used to estimate adjusted hazard ratios of the outcomes comparing DOACs with warfarin. Analyses were conducted independently at each site, with meta-analytical methods used to estimate pooled hazard ratios across sites.Results Of the 59 525 participants, 1967 (3.3%) had a major bleed and 1029 (1.7%) died over a mean follow-up of 85.2 days. The risk of major bleeding was similar for DOAC compared with warfarin use (pooled hazard ratio 0.92, 95% confidence interval 0.82 to 1.03), with the overall direction of the association favouring DOAC use. No difference was found in the risk of death (pooled hazard ratio 0.99, 0.84 to 1.16) for DOACs compared with warfarin use. There was no evidence of heterogeneity across centres, between patients with and without chronic kidney disease, across age groups, or between male and female patients.Conclusions In this analysis of adults with incident venous thromboembolism, treatment with DOACs, compared with warfarin, was not associated with an increased risk of major bleeding or all cause mortality in the first 90 days of treatment.Trial registration Clinical trials NCT02833987.

Concepts: Stroke, Thrombosis, Pulmonary embolism, Warfarin, Bleeding, Anticoagulant, Heparin, Anticoagulants

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Oral anticoagulant options have exploded. Dabigatran, a direct thrombin inhibitor, was approved for use in the United States in 2010 for the prevention of stroke in patients with atrial fibrillation; this was rapidly followed by approval of the direct factor Xa inhibitors rivaroxaban, apixaban, and edoxaban within 5 years. The drive for the development of these drugs stemmed from the burdens associated with the use of the anticoagulants that had previously been available for outpatient treatment - subcutaneous heparins and oral vitamin K antagonists. Although these new drugs represent an important advance in anticoagulation therapy, concern over the lack of . . .

Concepts: Atrial fibrillation, Warfarin, Anticoagulant, Heparin, Dabigatran, Anticoagulants, Vitamin K, Direct thrombin inhibitor

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To determine the real world risk of gastrointestinal bleeding associated with the use of the novel oral anticoagulants dabigatran and rivaroxaban compared with warfarin.

Concepts: Atrial fibrillation, Thrombosis, Pulmonary embolism, Warfarin, Anticoagulant, Heparin, Dabigatran, Anticoagulants

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 To study the effectiveness and safety of the non-vitamin K antagonist oral anticoagulants (novel oral anticoagulants, NOACs) dabigatran, rivaroxaban, and apixaban compared with warfarin in anticoagulant naïve patients with atrial fibrillation.

Concepts: Stroke, Atrial fibrillation, Thrombosis, Warfarin, Anticoagulant, Heparin, Dabigatran, Anticoagulants

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Intracerebral hemorrhage (ICH) is the most devastating adverse event in patients receiving oral anticoagulation. There is only sparse evidence regarding ICH related to the use of non-vitamin K antagonist oral anticoagulant (NOAC) agents.

Concepts: Stroke, Anticoagulant, Anticoagulants

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Three new oral anticoagulant agents were tested versus warfarin in separate, large phase III randomized clinical trials for prevention of any stroke and systemic embolism in atrial fibrillation. Dabigatran, a direct thrombin inhibitor, is at 110 mg bid non-inferior and at 150 mg bid superior to warfarin; rivaroxaban, a factor X inhibitor, is also non-inferior, and apixaban, also a factor X inhibitor, is superior to warfarin on the same efficacy end point. Statistical analysis of subgroups does not suggest, for any of the tested drugs, major differences in relation to different risk levels and history of previous stroke/TIA. This re-appraisal of data was undertaken in search for possible additional information, by considering the absolute differences in efficacy and safety events versus warfarin and the corresponding efficiency and number needed to treat, also with regard to secondary versus primary prevention. By this approach, it appears that for all drugs, equivalence or advantage versus warfarin on the efficacy end point is largely driven by a reduction in hemorrhagic rather than ischemic strokes. Dabigatran shows a balanced effect on ischemic and hemorrhagic strokes, and apixaban is most effective in sparing intracranial bleeding versus warfarin. In secondary prevention, better efficiency is shown by dabigatran 150 and apixaban, versus rivaroxaban, despite the higher proportion of post-stroke/TIA patients (55 %) in the ROCKET AF trial of rivaroxaban seemed to favor better results of this drug in secondary prevention. These and other results of our approach should not be directly translated into clinical practice. They may supply useful suggestions to be subsequently tested in specific trials, although head-to-head comparative studies of the three drugs remain unlikely.

Concepts: Clinical trial, Stroke, Atrial fibrillation, Warfarin, Anticoagulant, Heparin, Dabigatran, Anticoagulants

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Two new oral anticoagulants, rivaroxaban and dabigatran, with no need for anticoagulation monitoring, are available for patients with atrial fibrillation (AF). We aimed to compare their anticoagulant effects and safety when used during the AF ablation periprocedural period.

Concepts: Atrial fibrillation, Warfarin, Anticoagulant, Heparin, Dabigatran, Anticoagulants