Exploring pulse wave velocity as a vascular hemodynamic stress marker: more than just arterial stiffening?

Arterial pulse wave velocity (PWV), defined as the speed at which a blood pressure pulse propagates along the arterial tree, is the gold standard for assessment of arterial stiffness and can serve as an independent predictor of cardiovascular events, such as myocardial infarction, stroke, and heart failure. However, recent animal data suggest that pulse wave velocity measurements may not only assess arterial stiffness but also highly dynamic changes in local homeostasis and the delicate artery whole body interplay. This narrative review summarizes the major contributing factors to changes in pulse wave velocity and proposes novel classification into these factors as being either intrinsic or extrinsic to the vasculature. Intrinsic factors known to modulate pulse wave velocity include the elastin, collagen and calcium content of the arterial wall, smooth muscle tone, and endothelial cell function. In contrast, extrinsic factors include variables such as sex, and others that can fluctuate such as blood pressure, heart rate, metabolic health, and age. We highlight how increases in pulse wave velocity may be variable and oversimplified depictions of aortic stiffness and suggest that they are holistic measurements of vascular hemodynamic stress that also include the cumulative impact of mechanical forces, biochemical alterations, and structural and/or functional changes to the vasculature.