Prevalence of Thrombotic Complications in ICU-Treated Patients With Coronavirus Disease 2019 Detected With Systematic CT Scanning

Objective: Severe Coronavirus disease 2019 (COVID-19) is associated with an extensive pneumonitis, and frequent coagulopathy. We sought the true incidence of thrombotic complications in critically ill patients with severe COVID-19 on the intensive care unit (ICU), with or without extracorporeal membrane oxygenation (ECMO). Design: We undertook a single-centre, retrospective analysis of 72 critically ill patients with COVID-19 associated acute respiratory distress syndrome admitted to ICU. CT angiography of the thorax, abdomen and pelvis were performed on admission as per routine institution protocols, with further imaging as clinically indicated. The prevalence of thrombotic complications and the relationship with coagulation parameters, other biomarkers and survival were evaluated.. Setting: COVID-19 ICUs at a specialist cardiorespiratory centre. Patients: Seventy two consecutive patients with COVID-19 admitted to ICU during the study period (19/03/2020-23/06/2020). Interventions: None. Measurements and Main Results: All but one patient received thromboprophylaxis or therapeutic anticoagulation. Amongst 72 patients (M:F=74%; mean age: 52+10; 35 on ECMO), there were 54 thrombotic complications in 42 patients (58%), comprising 34 pulmonary arterial (47%), 15 peripheral venous (21%), and 5 (7%) systemic arterial thromboses / end-organ embolic complications. In those with pulmonary arterial thromboses, 93% were identified incidentally on first screening CT with only 7% suspected clinically. Biomarkers of coagulation (eg. D-dimer, Fibrinogen level, APTT) or inflammation (white cell count, CRP), did not discriminate between patients with or without thrombotic complications. Fifty-one patients (76%) survived to discharge; 17 (24%) patients died. Mortality was significantly greater in patients with detectable thrombus (33% vs. 10%, p=0.022). Conclusions: There is a high incidence of thrombotic complications, mainly pulmonary, amongst COVID-19 patients admitted to ICU, despite anticoagulation. Detection of thrombus was usually incidental, not predicted by coagulation or inflammatory biomarkers, and associated with increased risk of death. Systematic CT imaging at admission should be considered in all COVID-19 patients requiring ICU.