Efficacy and Safety of Apixaban in COVID-19 Coagulopathy Patients With Respiratory Severity Under Critical

There is an increased risk of Venous and Arterial thromboembolism in COVID-19 infection. The main reason being that the novel coronavirus SARS-CoV-2 induces hyperinflammation and subsequently immunothrombolism which is wide spread in the body. The angiotensin converting enzyme 2 (ACE2) receptor, which is utilized by the virus to infect the host, is present throughout the human body organs and endothelial cells. Thrombotic microangiopathies are the consequence of this direct endothelial invasion of the virus and widespread endothelial inflammation. Consequently, pervasive dysfunction of the endothelium and apoptosis is seen primarily due to the host immune response and release of pro inflammatory cytokines.

A hypercoagulable state is therefore seen due to the shift in the vascular equilibrium towards a vasoconstrictive and inflammatory response, promoting a microvascular derangement and dysfunctions.

Although this pathological response is not unique to the COVID-19 disease, the systemic coagulopathies observed due to this novel virus are noted to be slightly distinct. These include the increased risk of mortality with the increased level of D-Dimers in nearly 50% of the patients . While mild prolongation of Prothrombin time and thrombocytopenia are not noted to be important predictors of the severity of the disease or its adverse outcomes .

In COVID-19 patients, the International Society on Thrombosis and Hemostasis (ISTH). criteria for Disseminated Intravascular Coagulation (DIC) is seldom met, despite the indication by the typical triad of thrombin time prolonged, decreased platelet counts and increased D-dimer levels .

Although the Disseminated Intravascular Coagulation is low grade, the fibrinolytic system is activated and endogenous tissue plasminogen is released because of the pathogenic inflammation-causing endothelial cell injury and thrombotic angiopathies of the microvascular system. This also contributes to the increased mortalities due to high D-Dimer levels.