Approximately 2 million people in North America take the anticoagulant warfarin to prevent stroke, heart attack, and other events related to blood clots. Warfarin needs to be stopped before a person undergoes surgery or certain procedures because it can cause dangerous amounts of bleeding during and after surgery. Some doctors give a low molecular weight heparin (LMWH) to patients during the 2-week period when participants are without the effects of warfarin. The LMWH has the same effect as warfarin, but it acts and then leaves the system more quickly than warfarin. However, the LMWH is expensive, may increase the risk of bleeding, and has not been proven effective. This study will determine the safety and efficacy of an LMWH in adults with atrial fibrillation who stop warfarin in preparation for surgery. Show Participation in this study will last between 36 and 67 days. Participation will involve nine points of contact with researchers, at least two of which will be in-person visits at the research clinic. The others will be conducted by phone. All points of contact will include assessments on possible bleeding and any new symptoms. The first two of these points of contact, will take place at the signing of the informed consent, which will involve a screening of medical records and random assignment of participants to receive either the LMWH dalteparin or placebo. Participants will self-administer a subcutaneous injection of their assigned treatment twice a day for 3 days before the surgery or procedure and for 6 days after. During the course of the study, when participants visit their primary physicians for regularly scheduled appointments, it will be recommended that they undergo two international normalized ratio (INR) tests of blood clotting ability between day 2 and 10 after the surgery or procedure. The remaining seven points of contact will occur sometime between the day before surgery and 37 days after surgery. One of the in-person visits will occur within the first week after surgery and will include assessments on possible bleeding, any new symptoms, and INR results. Editor's Note: Commentary based on Douketis JD, Spyropoulos AC, Kaatz S, et al. Perioperative bridging anticoagulation in patients with atrial fibrillation. N Engl J Med. 2015 Jun 22. [Epub ahead of print]. Study Question In patients with atrial fibrillation (AF) on chronic warfarin therapy, does heparin bridging during interruption of warfarin therapy before and after an invasive procedure improve clinical outcomes? Methods This randomized, double-blind, placebo-controlled trial included patients with chronic AF or flutter who had received warfarin therapy for three months or longer, had an international normalized ratio (INR) in the therapeutic range, and were undergoing an elective invasive procedure requiring interruption of warfarin therapy. Patients with a mechanical heart valve; recent stroke, transient ischemic attack (TIA), or major bleeding event; and significant renal impairment were excluded. Participants were randomly assigned to receive bridging anticoagulation therapy with low-molecular-weight heparin (LMWH) or a matching subcutaneous placebo, from three days before the procedure until 24 hours before the procedure and then for five to ten after the procedure. Warfarin was stopped five days before the procedure and restarted within 24 hours after the procedure. The primary efficacy outcome was arterial thromboembolism at 30 days (stroke/TIA and systemic embolism), and the primary safety outcome was major bleeding at 30 days. Secondary outcomes included acute myocardial infarction, deep vein thrombosis, pulmonary embolism, death, and minor bleeding. Non-inferiority analysis with a non-inferiority margin of 1%, and a one-sided alpha level of 0.025 was used for the primary efficacy outcome. Results This study enrolled 1,884 patients (950 in the LMWH bridging arm and 934 in the placebo arm). The study participants were old (mean age of 71 years) with a mean CHADS2 score of 2.3 (CHADS2 score ≥3 in 38%). The incidence of arterial thromboembolism was 0.4% in the placebo arm and 0.3% in the LMWH bridging arm, with a mean between-group difference of 0.1% (95% confidence interval [CI] -0.6 to 0.8; P = 0.01 for non-inferiority). The incidence of major bleeding events was 1.3% in the placebo arm and 3.2% in the LMWH bridging arm. The relative risk for major bleeding associated with placebo as compared with LMWH bridging was 0.41 (95% CI 0.005). There were no significant differences between the two study arms for secondary efficacy outcomes. Conclusion Among patients with AF on chronic warfarin therapy who undergo invasive procedures requiring temporary interruption of warfarin, a periprocedural strategy of no bridging anticoagulation was non-inferior to periprocedural bridging with LMWH for prevention of arterial thromboembolic events. Furthermore, no bridging anticoagulation was also associated with a lower risk of major bleeding events. Commentary/Perspective Effectiveness of Bringing Anticoagulation for Surgery (The BRIDGE Study)1 addresses a frequently encountered clinical question of whether AF patients on chronic anticoagulation who undergo invasive procedures requiring warfarin interruption need periprocedural anticoagulation bridging. Current guidelines recommend periprocedural discontinuation of oral anticoagulants and bridging with LMWH or unfractionated heparin in AF patients at high risk for thromboembolic complications (American Heart Association grade 1C).2 In contemporary clinical practice, one in four AF patients who have interruption in oral anticoagulation therapy undergo periprocedural bridging.3 The present study provides conclusive evidence in favor of forgoing bridging anticoagulation among these patients, with a non-inferior risk of arterial thromboembolic events and significantly lower risk for major bleeding as compared with heparin bridging. Although thromboembolic events are generally more serious than major bleeding events, it is notable that bridging therapy led to an excess of 19 bleeding events for each thrombotic event prevented. These findings are consistent with previously reported observational findings from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF)3 and Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) sub-study4 that have demonstrated an increased risk of bleeding and no difference in thromboembolic complication risk among AF patients with versus without anticoagulation bridging in the periprocedural period. These findings also call into question the clinical practice pattern of prioritizing periprocedural thromboembolic risk prevention over the increased bleeding risk from bridging anticoagulation among AF patients. However, as highlighted by the authors, the results of the BRIDGE study should be interpreted in multiple clinical contexts. First, a majority of the study participants had low-to-moderate risk of stroke, and the study findings may not be applicable to higher risk patients. Second, patients undergoing procedures such as cardiac/neurological surgery, cancer surgeries, and vascular surgeries who are at a much higher risk for stroke were excluded from the study; thus, the study results may not apply to this patient population. Finally, the lower than expected rate of thromboembolic events among the study participants led to an overestimation of the non-inferiority margin and may have affected the power of the study to detect a significant benefit associated with bridging. Future studies are needed to address these unanswered questions about the effectiveness of periprocedural bridging strategy among AF patients who are at a high risk for systemic thromboembolic events and/or are undergoing high-risk procedures. References
Keywords: Anticoagulants, Atrial Fibrillation, Double-Blind Method, Embolism, Heart Valves, Heparin, Heparin, Low-Molecular-Weight, Incidence, International Normalized Ratio, Ischemic Attack, Transient, Myocardial Infarction, Neoplasms, Pulmonary Embolism, Registries, Risk, Stroke, Thromboembolism, Venous Thrombosis, Warfarin < Back to
Listings Which patients should receive bridging anticoagulation?Patients with Afib history.
Any patient with a TIA or CVA within the previous three months is automatically considered high risk.
Do you need to bridge for atrial fibrillation?As mentioned by the atrial fibrillation guidelines, it's reasonable to assess an individual patient's risk of stroke and bleeding to determine the need to bridge; however, the vast majority of patients are unlikely to benefit from bridging therapy.
Is Bridging necessary with eliquis?Because direct oral anticoagulants such as dabigatran, apixaban, rivaroxaban, and edoxaban provide their effects immediately they do not require bridging with unfractionated or low molecular weight heparin when starting therapy.
Does xarelto need bridging?Do I need to bridge patients with heparin or LMWH to XARELTO®? There is no need to bridge with heparin or LMWH for the DVT and PE treatment indications. XARELTO® can be used as a single, oral agent at the time of diagnosis; it can also be used following initial treatment with heparin or LMWH.
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Perioperative bridging anticoagulation in patients with atrial fibrillation
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