In post-ACS patients, PCSK9 inhibitor therapy reduces MACE significantly. This appears to be accomplished in two ways: directly by altering plaque composition and then stabilizing it, and indirectly by interfering with lipid metabolism and platelet aggregation. PCSK9 inhibitors improve endothelial function in patients with familial hypercholesterolemia, a well-known risk factor for cardiovascular disease. Here, PCSK9 is linked to familial hypercholesterolemia.