TFPI and COVID-19: Endothelial cell activation is associated with a hypercoagulable state in COVID-19 (210, 211), with proposed mechanisms including exocytosis of granules containing von Willebrand factor (vWF) and P-selectin (211) in addition to alteration in plasminogen activator inhibitor 1 (PAI-1) and tissue factor pathway inhibitor (TFPI) levels and upregulating cell adhesion molecules like VCAM and ICAM, which facilitates extravasation of circulating white blood cells (212) (Figure 1H).