Regarding thrombotic complications, AT III supplementation was associated with a reduced risk of thromboembolism in cardiac ECMO patients (RR = 0.45, 95% CI: 0.31–0.65) but was linked to an increased thromboembolism risk in adult patients (RR = 2.55, 95% CI: 1.32–4.94) and in other ECMO support types (RR = 1.62, 95% CI: 1.31–2.01). This evidence concerns the gene SERPINC1 and Thromboembolism.