Pacemaker or Defibrillator Surgery Without Interruption of Anticoagulation

Study Questions:

What is the effect of the current practice of bridging with heparin during pacemaker or implantable cardioverter-defibrillator (ICD) implantation, in patients at moderate to high risk of thromboembolic complications, versus continued warfarin therapy, on the incidence of device-pocket hematoma?

Methods:

The authors reported the results of BRUISE CONTROL (Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial), a multicenter, randomized, single-blind, controlled trial of continued warfarin versus bridging with low molecular weight heparin, in patients estimated to have at least a 5% annual predicted risk of thromboembolism (defined as CHADS2 score >2, mechanical mitral valve, high-risk mechanical aortic valve, recent venous thromboembolism, rheumatic atrial fibrillation [AF], AF with recent transient ischemic attack [TIA]/stroke, cardioversion during device implant, or high-risk thrombophilia—protein C, S, or anti-thrombin III deficiency, or anti-phospholipid antibodies). The primary outcome was clinically significant device-pocket hematoma, which was defined as device-pocket hematoma that necessitated prolonged hospitalization, interruption of anticoagulation therapy, or further surgery (e.g., hematoma evacuation).

Results:

This study was stopped early by the Data and Safety Monitoring Board, after the second prespecified interim analysis. There were significantly more device-pocket hematoma associated with bridging. Among study patients, 12 of 343 patients (3.5%) in the continued-warfarin group, as compared with 54 of 338 (16.0%) in the heparin-bridging group (relative risk, 0.19; 95% confidence interval, 0.10-0.36; p < 0.001), had device-pocket hematoma. Major complications were rare, and not different between the groups. These included one case each of tamponade and myocardial infarction in the bridging group, and one case each of TIA and stroke in the warfarin-continuation group.

Conclusions:

The authors concluded that, as compared with bridging therapy with heparin, a strategy of continued warfarin treatment at the time of pacemaker or ICD surgery markedly reduced the incidence of clinically significant device-pocket hematoma.

Perspective:

This very important study should inspire us to question many assumptions about anticoagulation and interrupting anticoagulation. Most clinicians believe they know that interrupting warfarin lowers periprocedural risk of bleeding in patients receiving warfarin anticoagulation. Further, most clinicians believe that bridging with heparin will minimize the period of time not anticoagulated, and therefore, mitigate any risk of interruption, without additional bleeding risk. This study clearly shows that these assumptions are not valid. The data suggest that bridging with heparin actually increases the risk of procedural bleeding dramatically, without any demonstrable increase in thromboembolic risk, although the study was underpowered to study thromboembolic events. Too often, we do things without evidence of benefit, but with only the presumption that doing something is better than doing nothing. Along with minor dental procedures (including extractions), which have been shown to be well tolerated during continuation of warfarin anticoagulation, we must now strongly consider adding pacer and ICD implantation—not because anticoagulation patients are not at increased risk of device-pocket hematoma, but because bridging with heparin likely only increases that risk. Primum non nocere.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Pulmonary Hypertension and Venous Thromboembolism, Vascular Medicine, Anticoagulation Management and Venothromboembolism, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias

Keywords: Protein C, Risk, Myocardial Infarction, Stroke, Ischemic Attack, Transient, Heparin, Low-Molecular-Weight, Warfarin, Electric Countershock, Venous Thromboembolism, Hematoma, Pacemaker, Artificial, Hospitalization, Hemorrhage, Defibrillators, Implantable


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