THBD and COVID-19: Diverse biomarkers have been proposed to assess endothelial function in both COVID-19 and post-COVID-19 patients, including flow-mediated dilation (FMD), lung diffusing capacity (DLCO) or vascular intima-media thickness (IMT) as non-invasive indicators; and circulating levels of vWF, tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), soluble thrombomodulin, angiopoietin-2, vascular cell adhesion molecule (VCAM), E selectin, circulating endothelial cells (CECs) or endothelial-colony forming cells (ECFCs) as invasive ones [3, 17].