REN and pulmonary edema: SARS-CoV-2 infection decreases the function of ACE-2 which can regulate the renin–angiotensin system, and may then result in vascular endothelial damage with increased permeability, and an inflammatory cascade effect because of dysfunction of the renin–angiotensin system, and may furtherly result in pulmonary edema, abnormal coagulation or disseminated intravascular coagulation [82,83,84].