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

S Schulman; J S Healey; J D Douketis; J Delaney; C A Morillo

doi:10.1016/j.thromres.2014.07.028

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

Thromb Res. 2014 Oct;134(4):814-8. doi: 10.1016/j.thromres.2014.07.028. Epub 2014 Aug 1.

Authors

S Schulman¹, J S Healey², J D Douketis³, J Delaney⁴, C A Morillo²

Affiliations

¹ Thrombosis and Atherosclerosis Research Institute, McMaster University, Hamilton, ON, Canada; Department of Medicine, Thrombosis Service, McMaster University, Hamilton, ON, Canada; Karolinska Institutet, Stockholm, Sweden. Electronic address: [email protected].
² Department of Medicine, Thrombosis Service, McMaster University, Hamilton, ON, Canada; Arrhythmia Services, Cardiology Division, McMaster University, Hamilton, ON, Canada; Population Health Research Institute, McMaster University, Hamilton, ON, Canada.
³ Thrombosis and Atherosclerosis Research Institute, McMaster University, Hamilton, ON, Canada; Department of Medicine, Thrombosis Service, McMaster University, Hamilton, ON, Canada.
⁴ Department of Medicine, Thrombosis Service, McMaster University, Hamilton, ON, Canada.

PMID: 25127655
DOI: 10.1016/j.thromres.2014.07.028

Abstract

Background: Perioperative 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.

Methods: In 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.

Results: The 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%).

Conclusion: The 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.

Trial registration: ClinicalTrials.gov NCT02094157.

Keywords: Anticoagulation; Atrial fibrillation; Defibrillator; Pacemaker; Surgery.

Publication types

Clinical Trial
Randomized Controlled Trial

MeSH terms

Anticoagulants / administration & dosage
Anticoagulants / adverse effects
Anticoagulants / therapeutic use*
Defibrillators, Implantable*
Female
Hematoma / chemically induced
Hemorrhage / chemically induced
Heparin, Low-Molecular-Weight / administration & dosage
Heparin, Low-Molecular-Weight / adverse effects
Heparin, Low-Molecular-Weight / therapeutic use*
Humans
International Normalized Ratio
Male
Pacemaker, Artificial*
Preoperative Care*
Preoperative Period
Thromboembolism / prevention & control
Vitamin K / therapeutic use
Warfarin / administration & dosage
Warfarin / adverse effects
Warfarin / therapeutic use*

Substances

Anticoagulants
Heparin, Low-Molecular-Weight
Vitamin K
Warfarin

Associated data

ClinicalTrials.gov/NCT02094157