Significance of Coagulopathy in Patients with Severe COVID-19 Supported with Veno-Venous Extracorporeal Membrane Oxygenation in United Kingdom - Multicentre Observational Study

COVID-19 is a prothrombotic condition and a major focus of attention has been to reduce thrombosis in order to improve outcomes. Extracorporeal membrane oxygenation (ECMO) triggers contact activation of coagulation, platelet dysfunction and systemic anticoagulation which may contribute to both thrombosis and bleeding complications. Methods: Multicentre observational study of mortality, thrombosis, and bleeding complications in 152 consecutive patients (≥18 years) supported with VV ECMO during the first wave of the COVID-19 pandemic (1st of March 2020 to 31st of May 2020) from four nationally commissioned UK ECMO centres. Findings: Of 152 patients, mortality during ECMO up to 120 days was 21.1% (32/152) whilst overall all cause in- hospital mortality up to 143 days from ECMO initiation was 25.7% (39/152). Median duration on ECMO was 17 days (interquartile range [IQR] 11-29.7). On multivariate analysis, mortality increased with age (Hazard ratio [HR] 1.09 [95% CI 1.03 - 1.14]), P=0.002. Rates of major bleeding and thrombosis during ECMO were 25.0% (38/152) and 17.1% (26/152). Presence of major bleeding prior to or at initiation of ECMO and intracranial haemorrhage during ECMO conferred 3.65 ([95% CI 1.16 - 11.48], P=0.027) and 6.92 ([95% CI 2.66 - 18.02], <0.0001) folds risks of death respectively during ECMO. Heparin induced thrombocytopenia was diagnosed in 16/152 (10.52%) of the patients and was independently associated with 4-fold increased risk of developing thrombosis (CI1.78-7.21), P=0.002. Thrombosis, coagulation and laboratory parameters did not predict mortality. Interpretation: Although thrombosis is a major complication in patients with COVID-19, major bleeding was frequent and independently associated with increased mortality. Despite a high incidence of major bleeding and thrombosis, both overall and 120-day mortality in this cohort of patients supported with ECMO were better than reported from international registries. Funding Statement: Bayer plc supported the study by providing the investigator-initiated funding to setup the multicentre database of the study. Declaration of Interests: DJA received funding from Bayer plc to setup the multicentre database of the study as an investigator-initiated funding. Other authors have no conflict of interest to declare. Ethics Approval Statement: The study was approved by the human research authority (HRA) and health and care Research Wales (HCRW) and the local Caldicott Guardian at Scotland (reference number: 20/HRA/1785). All patients lacked capacity, and the need for individual informed consent was waived because of observational nature of the study. Data was collected from patient clinical records by the treating medical team with no breach of privacy or anonymity.