Reduced-dose warfarin or interrupted warfarin with heparin bridging for pacemaker or defibrillator implantation: A randomized trial

•Preoperative reduced-dose warfarin without bridging was studied in terms of safety•The study was prematurely discontinued due to change in practice•The risk of pocket hematoma was similar to interrupted and bridged warfarin•The anticoagulant effect of reduced-dose warfarin was higher than expected on Day − 1•This resulted in frequent administration of vitamin K preoperatively

BackgroundPerioperative management with reduced-dose warfarin is of potential interest by eliminating the need for bridging while still maintaining a degree of anticoagulation. The outcomes of this regimen have not been well determined.MethodsIn a randomized controlled trial we compared two regimens for management of anticoagulation with warfarin in patients with implantation of a pacemaker or defibrillator. Half dose of warfarin for 3-6 days, depending on the baseline international normalized ratio (INR), before surgery aiming at an INR of ≤ 1.7 was compared with interrupted warfarin for 5 days with preoperative bridging with low-molecular-weight heparin (LMWH) at therapeutic dose for 2.5 days. Main safety outcome was pocket hematoma. Secondary outcomes were major bleeding, thromboembolism - all within 1 month, days of hospitalization and number of patients requiring correction of INR with vitamin K.ResultsThe study was planned for 450 patients but it was discontinued prematurely due to a change in practice. Pocket hematoma occurred in 4 of 85 patients (5%) randomized to the bridged regimen and in 3 of 86 patients (3%) randomized to reduced-dose warfarin. One pocket hematoma in each group was severe. There were no major hemorrhages or thromboembolism within the 1-month window. Duration of hospitalization was similar in the two groups. Correction of INR the day before surgery with vitamin K had to be used for significantly more patients in the reduced-dose warfarin group (41%) than in the bridged regimen group (6%).ConclusionThe reduced-dose warfarin regimen appeared to have similar safety after device implantation as interrupted warfarin with preoperative LMWH bridging. Due to premature discontinuation no firm conclusion can be drawn. The reduced-dose warfarin regimen often failed to achieve the intended preoperative INR.ClinicalTrials.gov Identifier: NCT 02094157