Extracorporeal membrane oxygenation (ECMO) requires systemic anticoagulation to reduce the risk of thromboembolic events. Despite its historic role, activated clotting time (ACT) remains a widely used heparin monitoring method. Systematic evidence on the association of ACT-guided monitoring with hemorrhagic or thromboembolic complications does not exist.

Systematic literature review and meta-analysis (Scopus and PubMed, July 2023).

All cohort studies.

Patients receiving ECMO support.

Anticoagulation monitoring with ACT.

We identified 3,177 publications, with 8 studies reporting the average ACT values for patients with and without bleeding. Meta-analysis revealed no significant difference in the compared groups (SMD = 0.69; 95% CI −0.05 to 1.43, p = 0.069; I² = 87.4%). Three studies (n = 117 patients) reported on the average ACT values for patients with thrombosis, without significant differences in ACT between patients with and without thrombosis (SMD = 0.47; 95% CI −0.50 to 1.44, p = 0.342; I² = 81.1%).

Even though ACT is a widely used heparin monitoring tool, the evidence on its association with hemorrhagic or thromboembolic events is still controversial and limited. Further studies are essential to elucidate the role of ACT in anticoagulation monitoring during ECMO support.