Venous and arterial thromboembolic complications in COVID-19 patients admitted to an academic hospital in Milan, Italy

Background Few data are available on the rate and characteristics of thromboembolic complications in hospitalized patients with COVID-19. Methods We studied consecutive symptomatic patients with laboratory-proven COVID-19 admitted to a university hospital in Milan, Italy (13.02.2020–10.04.2020). The primary outcome was any thromboembolic complication, including venous thromboembolism (VTE), ischemic stroke, and acute coronary syndrome (ACS)/myocardial infarction (MI). Secondary outcome was overt disseminated intravascular coagulation (DIC). Results We included 388 patients (median age 66 years, 68% men, 16% requiring intensive care [ICU]). Thromboprophylaxis was used in 100% of ICU patients and 75% of those on the general ward. Thromboembolic events occurred in 28 (7.7% of closed cases; 95%CI 5.4%–11.0%), corresponding to a cumulative rate of 21% (27.6% ICU, 6.6% general ward). Half of the thromboembolic events were diagnosed within 24 h of hospital admission. Forty-four patients underwent VTE imaging tests and VTE was confirmed in 16 (36%). Computed tomography pulmonary angiography (CTPA) was performed in 30 patients, corresponding to 7.7% of total, and pulmonary embolism was confirmed in 10 (33% of CTPA). The rate of ischemic stroke and ACS/MI was 2.5% and 1.1%, respectively. Overt DIC was present in 8 (2.2%) patients. Conclusions The high number of arterial and, in particular, venous thromboembolic events diagnosed within 24 h of admission and the high rate of positive VTE imaging tests among the few COVID-19 patients tested suggest that there is an urgent need to improve specific VTE diagnostic strategies and investigate the efficacy and safety of thromboprophylaxis in ambulatory COVID-19 patients.
Highlights • COVID-19 is characterized by coagulation activation and endothelial dysfunction. Few data are available on thromboembolic complications. • We studied symptomatic patients with laboratory-proven COVID-19 admitted to a university hospital in Milan, Italy (13.02-10.04.2020). • Venous and arterial thromboembolic events occurred in 8% of hospitalized patients (cumulative rate 21.0%) and 50% of events were diagnosed within 24 h of hospital admission. • Forty-four (11% of total) patients underwent VTE imaging tests; 16 were positive (36% of tests), suggesting underestimation of thromboembolic complications. • There is an urgent need to investigate VTE diagnostic strategies and the impact of thromboprophylaxis in ambulatory COVID-19 patients.