K. Kim1, C. Bowles1, Y. Juo1, R. Ou1, L. Mukdad1, S. Barajas Nuno1, H. Laks1,2, R. Shemin1,2, P. Benharash1,2 1David Geffen School Of Medicine, University Of California At Los Angeles,Los Angeles, CA, USA 2University Of California – Los Angeles,Cardiac Surgery,Los Angeles, CA, USA
Introduction: Thrombotic and embolic events as well as anticoagulation related bleeding continue to be the greatest contributor to postoperative complications following valve operations. Warfarin is considered a high-risk medication and among hospitalized patients, 7% of all medication errors are associated with anticoagulants increasing the risk of death in these patients by 20%. Beginning In 2008, the Joint commission required hospitals to develop and implement standardized anticoagulation practices to reduce adverse drug events and improve outcomes. To date, a simple and widely adapted warfarin protocol is lacking likely due to the heterogeneous metabolism of warfarin. This study aimed to evaluate the effect of INR monitoring and warfarin dosing in the immediate postoperative period.
Methods: All adult patients undergoing valvular heart surgery between January 2013 and December 2015 at our institution were identified using the local Society of Thoracic Surgeons (STS) Database. Patients were included if they were supposed to receive warfarin in the immediate postoperative period. Patient who received twice-daily INR checks and warfarin dosing were considered the intervention group and were propensity matched to those who received the standard daily dosing in the control group.The data was analyzed to determine length of hospital stay, days required to reach therapeutic INR, and the proportion of days during admission in which the INR was within therapeutic range.
Results: A total 76 patients (23 intervention group, 53 control group) were identified that met the inclusion criteria. None of the patients in the study had postoperative complications related to anticoagulation treatment. Analysis of data showed a statistically significant difference in the hospital length of stay (intervention: 13±7 days, control: 9±5 days; p=0.028) and time to reach therapeutic INR (intervention: 4±2 days, control: 6±4 days; p=0.013) between the intervention and control groups (Figure). The proportion of days during admission in which the INR was within therapeutic range for intervention and control groups 0.32 and 0.23 respectively, and this difference was not statistically significant.
Conclusion: In this single-center study, intensive anticoagulation monitoring and warfarin dosing following cardiac valve operations was associated with a longer hospital length of stay and less time to reach therapeutic INR. Our findings suggest that although intensive warfarin monitoring regimens may expedite therapeutic INR levels, they may not be cost efficient and may increase resource utilization. Given variations in practice, our findings warrant investigation in a randomized trial.
