Loading dose versus maintenance dose of warfarin for re-initiation after invasive procedures: a randomized trial.
J Thromb Haemost. 2014 May 19;
Authors: Schulman S, Hwang HG, Eikelboom JW, Kearon C, Pai M, Delaney J
Abstract
BACKGROUND: There is uncertainty regarding the optimal dosing regimen for resumption of warfarin after interruption for invasive procedures.
AIM: To determine the efficacy and safety of warfarin resumption with loading doses or with most recent maintenance dose.
METHODS: Patients on warfarin treatment and planned for invasive procedures with expected hospital stay of ≤1 day were randomized to resume warfarin on the day of the procedure, defined as Day 1, with most recent maintenance dose or with 2 intial days of double maintenance dose. Efficacy outcomes were proportion of international normalized ratio (INR) levels ≥2.0 on Day 5 (primary outcome) and day 10. Safety outcomes were bleeding and thromboembolic events. In addition, D-dimer levels were analyzed on Day 5 and 10 in a subset of the population.
RESULTS: There were 49 patients analyzed in each group. INR of ≥2.0 had been achieved by Day 5 for 13% in the Maintenance dose-group and for 50% in the Loading dose-group (relative risk [RR] 0.27; 95% confidence interval [CI], 0.10-0.60) and by Day 10 for 68% and 87%, respectively (RR 0.78; 95% CI, 0.65-1.00). There were no thromboembolic events, 1 major bleed before resumption of warfarin and 1 minor bleed - both in the Maintenance dose-group. There was no difference between the groups in proportion of patients with excessive INRs or elevated D-dimer levels or in the median D-dimer level.
CONCLUSION: Resumption of warfarin after minor-moderately invasive procedures with two loading doses achieves therapeutic INR faster than with only maintenance dose. This article is protected by copyright. All rights reserved.
PMID: 24837794 [PubMed - as supplied by publisher]