Coagulation disorders in SARS-CoV-2 infection.

A better understanding of the pathogenetic mechanisms triggered by SARS-CoV-2 infection may contribute to a more effective management of patients with COVID-19. Coagulation dysfunction is a key pathogenetic element of this disease as well as a challenge for practitioners. Marked inflammatory process found in severe forms of COVID-19, the complement activation, the cytokine storm, and disruption of the renin-angiotensin-aldosterone system are involved in the onset of thrombotic microangiopathy and large vessel coagulopathy. Virus-induced procoagulant activity occurs at the systemic level. Intravascular microthrombi disrupt vascularization in various tissues and organs, contributing to the occurrence of multiorgan failure and explain the higher morbidity and all-cause mortality of patients. It is estimated that almost 20% of patients with COVID-19 have significant coagulation disorders, and about a quarter of those hospitalized in intensive care units are prone to develop thrombosis events under prophylactic anticoagulant treatment. Some of patients who have been immunized after healing from the SARS-CoV-2 infection have a hypercoagulable state and are prone to develop thrombosis. Hypercoagulability is supported by thrombelastographic analysis: patients have an acceleration of the propagation phase of blood clot formation and higher clot strength. Markers of coagulation dysfunction in SARS-CoV2 are: decreased platelet count, increased INR, presence of fibrin degradation products, and especially higher plasma levels of D-dimers, which predict unfavorable outcome in these patients. Age, pre-existing diseases and associated risk factors, together with careful monitoring of clinical evolution and laboratory parameters allow the choice of the best personalized prophylactic or curative anticoagulant treatment.