Session II - Geriatric

Fri., 10/11/13 Geriatric, PAPER #40, 8:06 am OTA 2013

Effect of Vitamin K on Surgical Timing After Hip Fracture in Patients on Warfarin

Jacob Lantry, MD; John T. Gorczyca, MD;
University of Rochester Medical Center, Rochester, New York, USA

Purpose: This study was undertaken to characterize treatment patterns for patients sustaining a proximal femur fracture while taking warfarin.

Methods: All patients undergoing treatment of a proximal femur fracture over a 3-year period were identified using CPT codes from a surgical database at a Level I trauma center. 438 patients were identified and their charts reviewed. Patients with an international normalized ratio (INR) ≥1.5 at admission who were taking warfarin were included in the study. Treatment of the elevated INR was classified as either vitamin K administration or expectant management. Vitamin K administration and timing were recorded. Vitamin K administration was classified as immediate if received in the emergency department within 4 hours and delayed if given later. INR values throughout hospitalization and timing of surgery were recorded. INR values at presentation were compared using an independent samples t test. An analysis of variance (ANOVA) test was used to compare impact of treatment on INR over the first 24 hours, as well as on timing to surgery. Tukey HSD (honestly significant difference) was used for post hoc analysis. Fisher exact test was used to compare the percentage of patients able to go to surgery by the day after admission for each group.

Results: Of 438 patients, 40 (9.1%) had an elevated INR due to treatment with warfarin. There were 15 men and 25 women with an average age of 81 years (range, 34-100). Indications for taking warfarin were: atrial fibrillation (27), history of thromboembolic disease (8), both atrial fibrillation with history of thromboembolic disease (3), and prosthetic valve replacement (2). INR on admission averaged 2.2 (range, 1.5-4.1) for those managed expectantly and 2.8 (range, 1.6-7.4) for those treated with vitamin K (P = 0.06). 28 patients were treated with vitamin K and 12 patients were managed expectantly. Of patients treated with vitamin K, the medication was administered an average of 6.7 hours after the return of the initial INR laboratory value (range, 1-20 hours). Those who received immediate vitamin K (within 4 hours) had an average correction of 1.3 in their INR within 24 hours while those who had delayed administration had a correction of 0.3 and those who did not receive vitamin K had an average increase of 0.2 (P = 0.04). Post hoc testing showed significance was due to difference between the immediate vitamin K and expectant management groups (P <0.01). When vitamin K was given immediately, 75% of patients had surgery by the day after admission. When managed expectantly, 58% went to surgery by this time and when vitamin K treatment was delayed, 31% went to surgery by the day after admission (P = 0.06). No patient in any group had thromboembolic complication from correction of coagulopathy.

Conclusion: Treatment of the coagulopathic patient requiring urgent surgery is controversial and complicated. Patients who receive vitamin K early have quicker correction of INR. Patients who did not receive vitamin K showed no significant improvement in INR for 24 hours (average increase of 0.2) despite the fact that the INR was significantly lower. Most patient who received early vitamin K got surgery within 24 hours.

Alphabetical Disclosure Listing

• The FDA has not cleared this drug and/or medical device for the use described in this presentation   (i.e., the drug or medical device is being discussed for an “off label” use).  ◆FDA information not available at time of printing. Δ OTA Grant.