Clinical Features Comparing Arterial Thrombosis and Venous Thromboembolism in Hospitalized Patients with COVID-19: Result from the CLOT-COVID Study

Objectives: This study aimed to investigate the clinical features of arterial thrombosis and venous thromboembolism (VTE) in coronavirus disease 2019 (COVID-19). Methods: The CLOT-COVID Study was a retrospective, multicenter cohort study that enrolled 2,894 consecutively hospitalized patients with COVID-19 among 16 centers in Japan from April 2021 to September 2021. We compared the clinical features of arterial thrombosis and VTE. Results: Thrombosis was observed in 55 patients (1.9%) during hospitalization. Arterial thrombosis and VTE occurred in 12 (0.4%) and 36 (1.2%) patients, respectively. Among the 12 patients with arterial thrombosis, 9 (75%), 2 (17%), and 1 developed ischemic cerebral infarction, myocardial infarction, and acute limb ischemia, respectively, and there were five patients (42%) without comorbidities. Among 36 patients with VTE, 19 (53%) and 17 (47%) developed pulmonary embolism (PE) and deep vein thrombosis (DVT), respectively. PE was common in the early stages of hospitalization; whereas, DVT was common beyond the early stages of hospitalization. Conclusion: Among patients with COVID-19, arterial thrombosis was less common than VTE, although ischemic cerebral infarction seemed to be relatively common, and a certain number of patients developed arterial thrombosis even in the absence of known atherosclerosis risk factors.