In addition to laboratory and histopathological evidence of disordered coagulation and endothelial injury, several reports suggest that patients with COVID-19 are at high risk for developing clinically significant large-vessel thrombosis. Early anecdotal evidence of venous thromboembolism (VTE) in critically ill patients has been confirmed by multiple case series describing high rates of VTE in COVID-19, with incidence estimates ranging between 8% and 54% (18, 22), significantly exceeding those reported in critically ill patients with H1N1 influenza of 2% (36) and sepsis of 5% (30). Reports of large-vessel strokes in patients, including those younger than 50 yr, infected with SARS-CoV-2 also suggest hypercoagulability (28). Concordantly, a postmortem study of 12 patients positive for COVID-19 found thrombosis in 58% of cases, which was found to be responsible for 25% of deaths (45).