Hereditary/Acquired Bleeding Disorders

Recent research suggests that in patients with COVID-19, the thrombotic disorder characterized by micro- and macrothrombosis in the lungs and other organs and tissues is accompanied by an imbalance of von Willebrand factor (VWF) and ADAMTS13, a key enzyme regulating blood clotting via VWF function; this is evidenced by a high VWF/ADAMTS13 ratio. This review presents a detailed meta-analysis of 36 studies: 17 on VWF in COVID-19, 3 on ADAMTS13 and COVID-19, and 16 reporting on both VWF and ADAMTS13 in COVID-19. Patients with severe COVID-19, greater oxygen requirements, and admission to intensive care units rather than general wards had elevated VWF levels, and COVID-19 survivors had lower VWF levels. The authors found that development of thrombosis was associated with an imbalance of VWF and ADAMTS13, "evidenced by a high VWF/ADAMTS13 ratio, thus generating a clinical picture that closely resembles a secondary thrombotic microangiopathy."