Evaluation and standardization of current practices for reinitiation of warfarin therapy post-procedurally at a VA healthcare facility

Introduction: Current anticoagulation guidelines do not address optimal dosing of warfarin following peri-procedural interruption in patients bridged with low molecular weight heparin (LMWH). Several strategies may be used post-operatively, including reinitiation of the maintenance dose, which may result in prolonged reestablishment of a therapeutic international normalized ratio (INR) and continued need for LMWH bridging. Alternatively, a loading dose strategy has been found to achieve a therapeutic INR more rapidly.

Objectives: This quality improvement project aims to evaluate two strategies of warfarin dosing post-procedurally at a VA healthcare facility, to improve pharmacist interventions and optimize patient care.

Study Design: This is a 12-week, prospective, two-phase study, which has received Institutional Review Board exemption as a quality improvement project.

Methods: The first phase of this study included an anonymous survey of anticoagulation pharmacists to assess current warfarin reinitiation practices at a VA healthcare facility. The second phase will prospectively evaluate of two strategies of warfarin dosing for reinitiation post-procedurally in patients being bridged with LMWH. Time to therapeutic INR, discontinuation of LMWH, and 30-day outcomes will be evaluated for all patients.

Results: A survey of anticoagulation pharmacists evaluating warfarin reinitiation practices was completed in October 2015. Preliminary survey results found that all pharmacists use a 7-day follow-up to assess INR post-procedurally. There was also found to be consistency in that most pharmacists use a loading dose strategy for warfarin post-procedurally, however, the way in which this is done differs between individual pharmacists. Variation in dosing is expected to have an effect on time to a therapeutic INR.

Conclusions: Upon completion of this project, data analysis will be used to identify areas of improvement in the process of warfarin reinitiation within a VA healthcare facility. Results will be utilized to provide pharmacist education and standardization of clinic practices.