COVID-19 is frequently associated with abnormalities on coagulation testing and a coagulopathy driven by inflammation, intravascular coagulation activation, and microvascular thrombosis. Elevated D-dimer is the most common finding and is a predictor of adverse outcomes including thrombosis, critical illness, and death. Although COVID-19-associated coagulopathy has some similarities to disseminated intravascular coagulation, the platelet count is usually preserved, coagulation times are usually normal or minimally prolonged, and thrombosis is more common than bleeding, at least in noncritically ill patients. Bleeding is uncommon but may be a significant problem in critically ill patients, including those who may develop a consumptive coagulopathy with frank disseminated intravascular coagulation and those on extracorporeal membrane oxygenation. Blood product support to correct coagulopathy is reserved for bleeding patients or those requiring invasive procedures. Current recommendations suggest that all hospitalized patients should receive at least a prophylactic dose of anticoagulation. Results from a multiplatform randomized clinical trial suggest that therapeutically dosed anticoagulation may improve outcomes, including the need for organ support and mortality in moderately ill patients but not in those requiring critical care. The results of ongoing trials evaluating the impact of different antithrombotic strategies (therapeutic agents and intensity) on COVID-19 outcomes are eagerly awaited and are expected to have important implications for patient management. We also discuss COVID-19 vaccine-associated cytopenias and bleeding as well as vaccine-induced thrombotic thrombocytopenia, in which thrombosis is associated with thrombocytopenia, elevated D-dimer, and, frequently, hypofibrinogenemia.
Copyright © 2021 by The American Society of Hematology.