Thus, the aims of this paper are: (1) to evaluate the circulating EMP levels—namely CD31+/42− (PECAM-1), CD144 (VE Cadherin), and CD62e (E-selectin)—in combination with annexin V labelling in a hypercholesterolemia cohort representing patients with endothelial dysfunction; and (2) to assess the relationship between EMP and EDV as assessed via PWA, which is an established method of assessing endothelial function. The gene discussed is PECAM1; the disease is Hypercholesterolemia.