Thromboelastography Parameters and Platelet Count on Admission to the ICU and the Development of Venous Thromboembolism in Patients With Coronavirus Disease 2019

Abstract

Objectives: Determine if thromboelastography parameters and platelet count on the day of ICU admission are associated with the development of venous thromboembolism in patients with coronavirus disease 2019. Design: Prospective, observational cohort study. Setting: Tertiary-care, academic medical center in Nashville, TN. Patients: Patients with coronavirus disease 2019 pneumonia and acute respiratory failure admitted to the adult ICU without venous thromboembolism at the time of ICU admission. Intervention: None. Measurements and Main Results: The primary outcome was development of venous thromboembolism during the index hospitalization. Venous thromboembolism was defined by clinical imaging or autopsy, demonstrating deep vein thrombosis or pulmonary embolism. Forty consecutive critically ill adults with laboratory-confirmed coronavirus disease 2019 were enrolled; 37 (92.5%) were hypercoagulable by at least one thromboelastography parameter at the time of ICU admission and 12 (30%) met the primary outcome of venous thromboembolism during the index hospitalization. Patients who developed venous thromboembolism had decreased measures of clotting (maximum amplitude, alpha angle, shear elastic modulus parameter, and clotting index) on ICU admission thromboelastography compared with patients who did not develop venous thromboembolism (p < 0.05 for all measures). For each individual thromboelastography parameter used to dichotomize patients as hypercoagulable, the rate of venous thromboembolism was not higher in those identified as hypercoagulable; in fact, the venous thromboembolism rate was higher in patients who were not hypercoagulable by thromboelastography for maximum amplitude (p = 0.04) and alpha angle (p = 0.001). Platelet count was positively correlated with maximum amplitude, alpha angle, G parameter, and clotting index, and significantly lower in patients who developed venous thromboembolism than those who did not (median 186 vs 278 103/μL, p = 0.046). Venous thromboembolism was associated with inhospital mortality (odds ratio, 6.3; 95% CI, 1.4-29; p = 0.02). Conclusions: Our data do not support the use of thromboelastography to risk stratify critically ill adults with coronavirus disease 2019 for the development of venous thromboembolism or to guide decisions about anticoagulation. Lower platelet count on ICU admission, which may reflect platelet aggregation, was associated with venous thromboembolism.