Runtime and aPTT predict venous thrombosis and thromboembolism in patients on extracorporeal membrane oxygenation: a retrospective analysis

Introduction: Even though bleeding and thromboembolic events are major complications of extracorporeal membrane oxygenation (ECMO), data on the incidence of venous thrombosis (VT) and thromboembolism (VTE) under ECMO are scarce. Aims and objectives: This study analyzes the incidence and predictors of venous thrombosis and thromboembolism in patients treated with ECMO due to respiratory failure. Methods: Retrospective analysis of 102 patients treated on ECMO in our center from 04/2010 to 11/2015. Patients with thromboembolic events prior to admission were excluded. Diagnosis was made by imaging in survivors and postmortem examination in deceased patients. Results: We identified 42 survivors and 21 autopsy cases (mean age 46.0 ± 14.4 years; 37 (58.7%) male). 34 patients (54.0%) underwent ECMO therapy due to ARDS, 29 Patients (46.0%) with chronic organ failure were bridged to lung transplantation. Despite systemic anticoagulation at a mean PTT of 50.6 ± 12.8 s, (VT/VTE 47.0 ± 12.3 s and no VT/VTE 53.63 ± 12.51 s (P = 0.037)), VT and/or VTE were observed in 29 cases (46.1%). The rate of V. cava thrombosis was 15/29 (51.7%). Diagnosis of pulmonary embolism prevailed in deceased patients (5/21 (23.8%) versus 2/42 (4.8%) (P= 0.036). In a multivariable analysis only aPTT and time on ECMO predicted VT/VTE. There was no difference in the incidence of clinically diagnosed VT in ECMO survivors and autopsy findings. Conclusions: Venous thrombosis and thromboembolism following ECMO therapy are frequent and might influence outcome. Quality of anticoagulation and ECMO runtime predicted thromboembolic events. Current aPTT recommendations might be too low.