- Question
- In patients at high thromboembolic risk undergoing pacemaker or implantable cardioverter-defibrillator (ICD) surgery, is it safer to continue warfarin or to interrupt it and bridge with heparin?
- Design
- Randomized, single-blind trial comparing two perioperative anticoagulation strategies. It was funded by the Canadian Institutes of Health Research and the Ministry of Health and Long-Term Care of Ontario, and the data and safety monitoring board recommended stopping it after the second prespecified interim analysis.
- Population
- Patients needing pacemaker or ICD surgery who were taking warfarin and had an annual risk of thromboembolic events of 5% or more.
- Intervention
- Continued warfarin treatment throughout device surgery, without interruption.
- Control
- Warfarin interruption with bridging therapy using heparin (low-molecular-weight heparin or intravenous unfractionated heparin).
- Primary outcome
- Clinically significant device-pocket hematoma, defined as a hematoma that necessitated prolonged hospitalization, interruption of anticoagulation, or further surgery (e.g., hematoma evacuation).
- Results
- Clinically significant hematoma occurred in 12 of 343 patients (3.5%) with continued warfarin versus 54 of 338 (16.0%) with heparin bridging (relative risk, 0.19; 95% CI, 0.10 to 0.36; P<0.001).
- Safety
- Major surgical and thromboembolic complications were rare and did not differ significantly between groups: one cardiac tamponade and one myocardial infarction occurred in the heparin-bridging group, and one stroke and one transient ischemic attack in the continued-warfarin group.
- Conclusion
- Continuing warfarin during pacemaker or ICD surgery markedly reduced clinically significant pocket hematoma compared with heparin bridging.
- Why it matters
- The trial provided randomized evidence to move away from routine heparin bridging and to operate on these patients without interrupting warfarin, simplifying perioperative management.
Card generated automatically with AI from the abstract of the original publication and the trial registry; every figure was checked against those sources. It may contain errors: verify the data at the source before using it for clinical decisions.
Generated on October 14, 2026