Anti-Xa-guided anticoagulation with unfractionated heparin and thrombosis during ECMO support: A systematic review and meta-analysis

Objective The initiation of extracorporeal life support (ECMO) triggers complex coagulation processes, necessitating systemic anticoagulation. Therefore, anticoagulation monitoring is crucial to avoid adverse events such as thrombosis and haemorrhage. The main aim of this work is to analyse the association between anti-Xa levels and thrombosis occurrence during ECMO support. Design Systematic literature review and meta-analysis (Scopus and PubMed, up to July 29, 2023) Setting All retrospective and prospective studies Participants Patients receiving ECMO support Intervention Anticoagulation monitoring during ECMO support Measurements and main results We included 16 articles with 1968 patients in the review and 7 studies in the meta-analysis (n = 374). Patients with thrombosis had significantly lower mean anti-Xa values (SMD -0.36; 95%CI -0.62; -0.11, p <0.01). Furthermore, we observed a positive correlation between unfractionated heparin infusion and anti-Xa levels (pooled estimate of correlation coefficients 0.31; 95% CI 0.19; 0.43, p < 0.001). The most common adverse events were major bleeding (42%) and any kind of haemorrhage (36%), followed by thromboembolic events (30%) and circuit or oxygenator membrane thrombosis (19%). More than half of the patients did not survive until discharge (52%). Conclusions Our work revealed significantly lower levels of anti-Xa in patients experiencing thromboembolic events, and a positive correlation between anti-Xa and unfractionated heparin infusion. Considering the contemplative limitations of conventional monitoring tools, further research on the role of anti-Xa is warranted. New trials should be encouraged to confirm our findings and determine the most suitable monitoring strategy for patients receiving ECMO support.