Brinkman, Hannah M.

ABSTRACT Background The Extracorporeal Life Support Organization recommends daily antithrombin monitoring and supplementation to achieve > 50%–80% activity during extracorporeal membrane oxygenation (ECMO). Evidence supporting this practice is uncertain, and whether it confers clinical benefit or harm is unclear. Methods This was a systematic review with meta‐analysis to evaluate the safety and efficacy of antithrombin supplementation during ECMO. We systematically searched databases and registers for studies comparing patients on ECMO who received antithrombin supplementation to those who did not. Random effects meta‐analysis was performed. Risk of bias was independently assessed by two investigators. A priori subgroup and sensitivity analyses were performed to explore reasons for heterogeneity. Results A total of 11 studies were identified. In the pooled meta‐analysis, antithrombin supplementation resulted in no difference in bleeding events (OR 1.38, 95% CI, 0.88–2.17, p = 0.16), thrombotic events (OR 1.57, 95% CI, 0.84–2.90, p = 0.15), or mortality (OR 1.21, 95% CI, 0.81–1.81, p = 0.35) when compared to those who did not receive antithrombin. Subgroup analysis revealed no difference in bleeding events or mortality in pediatric or adult patients; however, pediatric patients that received antithrombin were more likely to experience a thrombotic event (OR 1.70, 95% CI, 1.51–1.91). Sensitivity analysis in only low risk of bias studies confirmed these findings. Conclusions Antithrombin supplementation was not associated with differences in mortality or hemostatic outcomes during ECMO support and may be associated with harm in pediatric patients on ECMO.

Empirical evidence suggests direct thrombin inhibitors (DTIs) produce more favorable hemostatic outcomes than heparin in patients supported by extracorporeal membrane oxygenation (ECMO), yet the exact mechanisms responsible are unknown. We systematically searched databases and registers for studies comparing DTIs to heparin in humans receiving ECMO. A total of 28 studies were identified, most of which (n = 25) used bivalirudin, while the rest (n = 3) used argatroban. In random-effects meta-analysis, DTIs achieved the therapeutic anticoagulation range faster (mean difference = −6.96 hours, 95% confidence interval [CI] = −11.98 to −1.95, p = 0.006) and maintained the therapeutic range for a greater proportion of time (mean difference = 18.6%, 95% CI = 8.78–28.42, p < 0.001) than heparin. Subgroup analysis revealed these effects were similarly significant in adult patients and when bivalirudin was the DTI; however, they were not significant in pediatric patients or when argatroban was the DTI. Sensitivity analysis confirmed robustness of the primary findings in only low-risk of bias studies and in only studies published as full papers. In summary, DTIs—specifically bivalirudin—were associated with faster time to therapeutic anticoagulation and maintained the goal range for a greater percentage of time than heparin during ECMO support.