Thrombotic Events Develop in 1 Out of 5 Patients Receiving ECMO Support: An 11-Year Referral Centre Experience

Background: The use of extracorporeal membrane oxygenation (ECMO) for critically ill patients is growing rapidly given recent developments in technology. However, adverse events are frequently reported that have potentially devastating impacts on patient outcomes. The information on predictors and risk factors for thrombotic events, especially that focusing on the comparison of veno-arterial and veno-venous ECMO configurations, are still inconsistent and sparse; therefore, we aimed to close this gap. Methods: We performed a retrospective analysis of all patients on extracorporeal life support admitted to the intensive care units of a tertiary university center in Europe. Results: From 645 patients, 417 who received extracorporeal life support due to cardiogenic shock (290, 70%), respiratory failure (116, 28%) or hypothermia (11, 3%) were included. In total, 22% (92) of the patients experienced thrombotic events with a similar incidence in both ECMO configurations. Anticoagulation consisted of unfractionated heparin (296, 71%) and argatroban (70, 17%). Univariate Cox analyses identified hemoconcentration and increased maximal clot firmness (thromboelastometry) as risk factors for thrombosis. Moreover, the patients experiencing thrombosis had longer ECMO duration and intensive care stays. Conclusions: ECMO is a specialized life-support modality with a high risk of complications. A longer ECMO duration is associated with thrombosis occurrence in patients receiving ECMO support. Following hemorrhage, thromboembolic complications are common adverse events. However, in contrast to major bleeding, no impact on mortality was observed. The question arises if a protocol with less anticoagulation may have a role to play in the future.