ELN and endothelial dysfunction: These immune responses activate matrix metalloproteinases, which degrade key structural proteins—elastin and collagen—in the aortic media, leading to cystic medial necrosis, elastin fragmentation, smooth muscle cell loss, and proteoglycan pooling.3, 4, 5 Simultaneously, Lp(a) promotes oxidative stress and endothelial dysfunction, accelerating cell senescence, disrupting endothelial barrier integrity, and impairing nitric oxide–mediated vasodilation.4