# Evaluation of bivalirudin-based anticoagulation for extracorporeal membrane oxygenation, including patients with COVID-19

## TL;DR

This study evaluates bivalirudin as an anticoagulant for ECMO, finding it effective but noting longer adjustment times in patients with COVID-19.

## Contribution

The study evaluates a pharmacist-directed bivalirudin protocol for ECMO anticoagulation and identifies differences in patients with and without COVID-19.

## Key findings

- Median time to achieve therapeutic aPTT was 8.9 hours pre-protocol and 14.2 hours post-protocol.
- Patients with COVID-19 had a significantly longer time to reach therapeutic aPTT (26.5 vs. 8.6 hours).
- Median number of dose adjustments was higher in patients with COVID-19 (4 vs. 2).

## Abstract

Background: Although unfractionated heparin (UFH) has traditionally been used for anticoagulation during extracorporeal membrane oxygenation (ECMO), bivalirudin may be preferred due to fewer complications. A prior medication use evaluation of ECMO patients who received bivalirudin resulted in dosing updates for our pharmacist-directed bivalirudin protocol. This study intended to evaluate the efficacy and safety of bivalirudin for anticoagulation during ECMO support post-protocol initiation. Methods: This was a retrospective, single-center, pre-post study. Adult patients requiring ECMO support for at least 24 h and who received bivalirudin between January 1, 2015 to July 31, 2018 (pre-group) and May 1, 2019 to June 30, 2021 (post-group) were included. Results: There were 38 patients in the pre- and 35 patients in the post-group. The primary outcome, median time to two consecutive activated partial thromboplastin times (aPTTs) within therapeutic range for the initial goal range, was 8.9 h in the pre- and 14.2 h in the post-group (p = 0.517). In a subgroup analysis of the post-group, the primary outcome was higher in patients with COVID-19 (26.5 vs. 8.6 h, p = 0.018). The median number of dose adjustments to achieve goal aPTT was higher in COVID-19 patients (4 vs. 2, p = 0.017). Conclusion: These results suggest that a standardized pharmacist-directed protocol for bivalirudin in ECMO achieves timely therapeutic anticoagulation levels. Patients with COVID-19 trended toward longer times to two consecutive therapeutic aPTTs. Further studies are needed to evaluate dosing strategies in patients with and without COVID-19.