Continuation of warfarin during pacemaker or implantable cardioverter-defibrillator implantation: A randomized clinical trial

Background: Management of oral anticoagulation in patients undergoing pacemaker (PPM) or implantable cardioverter-defibrillator (ICD) implantation remains controversial. Prior studies demonstrate that continuation of warfarin may be safer when compared with strategies requiring interruption and/or heparin bridging. Limited data from randomized trials exist. Objective: We conducted a randomized trial to determine whether warfarin continuation is superior to warfarin interruption during PPM or ICD implantation. Methods: Patients on oral anticoagulation referred for PPM or ICD implantation were randomized to warfarin continuation versus interruption. Patients randomized to warfarin interruption were further stratified into two groups based on their risk for thromboembolic events in the absence of warfarin. Moderate-risk patients were randomized to warfarin continuation versus warfarin interruption. High-risk patients were randomized to warfarin continuation versus warfarin interruption with heparin bridging. The primary combined outcome included thromboembolic events, anticoagulant-related complications, or any significant bleeding necessitating additional intervention or discontinuation of anticoagulation. Results: We studied 100 patients (average age 70.8 years, 21% female, mean body mass index 28.4) who underwent 64 ICD and 36 PPM implantations. Fifty patients were assigned to continue warfarin. The randomized groups were well matched. Among patients randomized to warfarin interruption, there were two pocket hematomas, one pericardial effusion, one transient ischemic attack, and one patient who developed heparin-induced thrombocytopenia. No events were noted among patients continuing warfarin (P = .056). Conclusions: While the results were not statistically significant, there was a trend toward reduced complications in patients randomized to warfarin continuation. This strategy should be considered in patients undergoing PPM or ICD implantation.