Contemporary Anticoagulation Reversal Focus on Direct Thrombin Inhibitors and Factor Xa Inhibitors

Propensity matched analysis examining the effect of passive reversal of direct oral anticoagulants on blood loss and the need for transfusions among traumatic geriatric hip fractures

BACKGROUND

Reversal of direct oral anticoagulants (DOACs) is currently recommended prior to emergent surgery, such as surgical intervention for traumatic geriatric hip fractures. However, reversal methods are expensive and timely, often delaying surgical intervention, which is a predictor of outcomes. The study objective was to examine the effect of DOAC reversal on blood loss and transfusions among geriatric patients with hip fractures.

METHODS

This retrospective propensity-matched study across six level I trauma centers included geriatric patients on DOACs with isolated fragility hip fractures requiring surgical intervention (2014-2017). Outcomes included: intraoperative blood loss, intraoperative pRBCs, and hospital length of stay (HLOS).

RESULTS

After matching there were 62 patients (31 reversed, 31 not reversed), 29 patients were not matched. The only reversal method utilized was passive reversal (waiting ≥ 24 hours for elimination). Passively reversed patients had a longer time to surgery (mean, 43 vs. 18 hours, p < 0.01). Most patients (92%) had blood loss (90% passively reversed, 94% not reversed); the median volume of blood loss was 100 mL for both those groups, p = 0.97. Thirteen percent had pRBCs transfused (13% passively reversed and 13% not reversed); the median volume of pRBCs transfused was 525 mL for those passively reversed and 314 mL for those not reversed, p = 0.52. The mean HLOS was significantly longer for those passively reversed (7 vs. 5 days, p = 0.001).

CONCLUSIONS

Passive DOAC reversal for geriatric patients with isolated hip fracture requiring surgery may be contributing to delayed surgery and an increased HLOS without having a significant effect on blood loss or transfusions. These data suggest that passive DOAC reversal may not be necessary prior to surgical repair of isolated hip fracture.

Partial warfarin reversal prior to hip fracture surgical intervention in geriatric trauma patients effects on blood loss and transfusions

BACKGROUND

Warfarin reversal is typically sought prior to surgery for geriatric hip fractures; however, patients often proceed to surgery with partial warfarin reversal. The effect of partial reversal (defined as having an international normalized ratio [INR] > 1.5) remains unclear.

METHODS

This was a retrospective cohort study. Geriatric patients (≥65 y/o) admitted to six level I trauma centers from 01/2014-01/2018 with isolated hip fractures requiring surgery who were taking warfarin pre-injury were included. Warfarin reversal methods included: vitamin K, factor VIIa, (a)PCC, fresh frozen plasma (FFP), and the "wait and watch" method. An INR of ≤ 1.5 defined complete reversal. The primary outcome was the volume of blood loss during surgery; other outcomes included packed red blood cell (pRBC) and FFP transfusions, and time to surgery.

RESULTS

There were 135 patients, 44% partially reversed and 56% completely reversed. The median volume of blood loss was 100 mL for both those completely and partially reversed, p = 0.72. There was no difference in the proportion of patients with blood loss by study arm, 95% vs. 95%, p > 0.99. Twenty-five percent of those completely reversed and 39% of those partially reversed had pRBCs transfused, p = 0.08. Of those completely reversed 5% received an FFP transfusion compared to 14% of those partially reversed, p = 0.09. There were no statistically significant differences observed for the volume of pRBC or FFP transfused, or for time to surgery.

CONCLUSIONS

Partial reversal may be safe for blood loss and blood product transfusions for geriatric patients with isolated hip fractures. Complete warfarin reversal may not be necessary prior to hip fracture surgery, especially for mildly elevated INRs.

Evaluation of Dosing Practices of Rivaroxaban and Dabigatran

Background: Anticoagulation is standard practice for the prevention and treatment of thromboembolic events. Two of the newer agents, rivaroxaban (Xarelto) and dabigatran (Pradaxa) are being utilized frequently in the inpatient and outpatient settings. Prescribers may not appreciate the need for dose reduction in the setting of renal insufficiency. Objective: The objective of this study was to evaluate whether rivaroxaban and dabigatran were dosed according to recommendations in the package insert for patients with renal insufficiency. Methods: Eligible patients were those >18 years of age who received rivaroxaban or dabigatran as an inpatient or had a prescription filled from the outpatient pharmacy. The use of the Cockcroft–Gault equation was utilized to calculate creatinine clearance to evaluate whether patients had appropriate manufacturer recommended dose reductions based on their renal function. Results: There were very few patients (8 of 355, or 2.3%) who should have received a reduced dose when creatinine clearance was calculated utilizing actual body weight. In those patients with renal insufficiency, 3 of 6 (50.0%) patients receiving rivaroxaban and 1 of 2 (50%) patients receiving dabigatran were appropriately dosed. When ideal body weight was substituted for creatinine clearance calculation, there were 15 patients receiving rivaroxaban and 10 patients receiving dabigatran who fell below the creatinine clearance threshold for dose reduction. Conclusions: Based on this evaluation, very few patients required a dose reduction due to renal insufficiency. It is important for clinicians to always monitor renal function when utilizing these medications to optimize the benefits of the new oral anticoagulants while limiting potential deleterious effects. Furthermore, it is necessary to ensure that actual body weight is being utilized for creatinine clearance calculations with the new oral anticoagulants and not to base dosing on estimated glomerular filtration rate or other calculated creatinine clearance as this could lead to inappropriate dose reductions.

Hematologic issues in the geriatric surgical patient

Geriatric patients are at higher risk for hemorrhagic complications after surgery and traumatic injuries. The geriatric population is more likely to take anticoagulant or antiplatelet medications. Chronic disease, autoimmune disease, and nutritional deficiencies can lead to coagulation factor and platelet disorders. One must be familiar with the current anticoagulant and antiplatelet medications, their mechanism of action, and reversal agents to properly care for this group of patients. The new oral anticoagulants do not have Food and Drug Administration (FDA) approved reversal agents, but known procoagulant agents with other FDA indications may be effective.