Abstract
Most patients affected by the novel coronavirus SARS-CoV-2 — responsible for the Coronavirus disease, COVID-19 — remain asymptomatic or develop mild symptoms. Only a small percentage of cases develop a severe disease that may lead to a fatal outcome. Since the early reports published in the literature by Wuhan colleagues, we have learned that patients hospitalized for acute COVID-19 infection have different clinical and laboratory pictures of coagulopathy. In particular, a marked increase in blood clotting capacity has been reported in most hospitalized patients – COVID-19-associated coagulopathy, CAC – which in turn increases the risk of developing thrombotic complications. The main pathophysiological mechanisms underlying this hypercoagulable state are inflammation, endothelial damage, hypofibrinolysis and hypoxemia. Traditional coagulation tests fail to fully characterize the nature and severity of COVID-19-associated hypercoagulability (CAH). Hence the need for functional coagulation assays (i.e. tromboelastometry/graphy, thrombin generation, platelet function test) and circulating extracellular vesicles to better understand these peculiar conditions. Moreover, it would be very helpful to use these tests to identify patients at increased risk of developing thrombotic complications or with a worse prognosis as well as to ascertain the effectiveness of the anticoagulant treatment. The aim of our narrative review was to describe the main pathophysiologic mechanisms of CAH and to summarize the current knowledge on functional coagulation assays and extracellular vesicles tests in CAH.