780: 5 MG OF IV VITAMIN K IS SAFE AND EFFECTIVE TO REVERSE LIFE-THREATENING BLEEDS SECONDARY TO WARFARIN

Abstract

Introduction: Vitamin K is a cofactor in the synthesis of clotting factors. It can be administered to counteract the effects of vitamin K antagonists (e.g., warfarin). The 2020 American College of Cardiology Guidelines recommend 5-10 mg of intravenous (IV) vitamin K for reversal of major bleeding due to warfarin, though the optimal dose of IV vitamin K to rapidly lower the INR to a safe range is unknown. Therefore, the purpose of this study is to compare the guideline-recommend dosing range of 5 mg vs. 10 mg for safety and efficacy. Methods: This single center, retrospective cohort study included patients with life-threatening bleeding secondary to warfarin who received IV vitamin K at Loyola University Medical Center from January 1st, 2014 - July 19, 2022. The primary endpoint of this study is percentage of patients below INR goal ≤1.5 at 24 hours (±12 hours). Secondary endpoints include thromboembolic events and 30-day mortality. This study is IRB approved. Results: Of the 94 patients with life-threatening bleeding, 56 patients met inclusion criteria. Fourteen patients received 5 mg of IV vitamin K and 42 patients received 10 mg. More patients in the 5 mg group had intracranial hemorrhage (85.7% vs. 66.7%). The median baseline INR for the 5 mg group was 2.7 (inner quartile range [IQR] 2-4) vs. 3.3 (2.6-5.8) in the 10 mg group. The primary endpoint of INR goal ≤1.5 within 24 hours of administration was achieved in 85.7% of both dosing groups. A multivariable logistic regression, performed to identify predictive factors of goal INR attainment at 24 hours and adjust for baseline INR found an increase in sequential organ failure assessment score significantly decreased the odds of achieving an INR goal < 1.5 (odds ratio 0.72, 95% confidence interval 0.59-0.89). Two thromboembolic events occurred in the 10 mg group compared to zero in the 5 mg group. Thirty-day mortality was similar between groups. Conclusions: A dose of 5 mg of IV vitamin K is safe and effective in lowering an INR to goal < 1.5 without causing thromboembolic events or significantly increasing mortality.