Serial Thromboelastography and the Development of Venous Thromboembolism in Critically Ill Patients With COVID-19

To test the hypothesis that relatively lower clot strength on thromboelastography maximum amplitude (MA) is associated with development of venous thromboembolism (VTE) in critically ill patients with COVID-19. DESIGN: Prospective, observational cohort study. SETTING: Tertiary care, academic medical center in Nashville, TN. PATIENTS: Patients with acute respiratory failure from COVID-19 pneumonia admitted to the adult medical ICU without known VTE at enrollment. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Ninety-eight consecutive critically ill adults with laboratory-confirmed COVID-19 were enrolled. Thromboelastography parameters and conventional coagulation parameters were measured on days 0 (within 48 hr of ICU admission), 3, 5, and 7 after enrollment. The primary outcome was diagnosis of VTE with confirmed deep venous thrombosis and/or pulmonary embolism by clinical imaging or autopsy. Twenty-six patients developed a VTE. Multivariable regression controlling for antiplatelet exposure and anticoagulation dose with death as a competing risk found that lower MA was associated with increased risk of VTE. Each 1 mm increase in enrollment and peak MA was associated with an 8% and 14% decrease in the risk of VTE, respectively (enrollment MA: subdistribution hazard ratio [SHR], 0.92; 95% CI, 0.87–0.97; p = 0.003 and peak MA: SHR, 0.86; 95% CI, 0.81–0.91; p < 0.001). Lower enrollment platelet counts and fibrinogen levels were also associated with increased risk of VTE (p = 0.002 and p = 0.01, respectively). Platelet count and fibrinogen level were positively associated with MA (multivariable model: adjusted R(2) = 0.51; p < 0.001). CONCLUSIONS: When controlling for the competing risk of death, lower enrollment and peak MA were associated with increased risk of VTE. Lower platelet counts and fibrinogen levels at enrollment were associated with increased risk of VTE. The association of diminished MA, platelet counts, and fibrinogen with VTE may suggest a relative consumptive coagulopathy in critically ill patients with COVID-19.