It has been discovered that SARS-CoV-2 enters cells by binding to angiotensin-converting enzyme 2 (ACE2), which is widely expressed in endothelial cells, SARS-CoV-2 can cause extensive damage to endothelial cells, leading to endothelial dysfunction, which disrupts the balance between coagulation, anticoagulation, and fibrinolysis, resulting in a significant tendency for thrombus formation and activation of the fibrinolysis system, and elevated levels of D-dimer may reflect fibrinolysis (McGonagle et al., 2020). This evidence concerns the gene ACE2 and endothelial dysfunction.