ACE2 and COVID-19: Mechanistically, pre-existing cardiovascular diseases may aggravate COVID-19 by the interaction between the viral spike protein of SARS-CoV-2 and angiotensin-converting enzyme 2, which leads to an imbalance of the renin-angiotensin-aldosterone system (RAAS), increased endothelial cell damage, thromboinflammation, and dysregulated immune response [5,8].