Aortic Stiffness

Arterial stiffness is the inverse of the distensibility of large arteries such as the aorta, whose cushioning function normally distends during systole and recoils during diastole to transform pulsatile flow into steady flow in the microcirculation. ^[1] Aortic stiffness is usually considered an index of vascular aging, with individuals excessively affected by risk factors representing early vascular aging and those resistant to them representing supernormal vascular aging. ^[2] Stiffening of the aorta, measured by aortic pulse wave velocity, is independently associated with adverse cardiovascular outcomes across many patient groups and in the general population. ^[3]

The main structural contributors to arterial stiffening are extracellular matrix proteins that bear the mechanical load and vascular smooth muscle cells, with chronic high blood pressure accelerating collagen production and elastin degradation. ^{[1] [4]} A loss of elastic properties increases pulse pressure and left ventricular load and exposes the microvasculature of the brain and kidneys to wider pressure fluctuations, which may increase the risk of stroke and renal failure. ^{[3] [2]} Higher aortic stiffness is associated with poorer performance on cognitive memory tests and with microvascular alterations and medial temporal lobe atrophy that contribute to dementia pathogenesis. ^[5]