On arterial physiology, pathophysiology of vascular compliance, and cardiovascular disease.

Traditionally, the main emphasis in hypertension treatment has been on lowering diastolic blood pressure. Recently, this emphasis has been shifting toward systolic blood pressure and pulse pressure, the latter of which might be a better indicator of future clinical events than either blood pressure reading alone or in combination. Increased pulse pressure indicates increased arterial stiffness and hence is commonly seen in older subjects. As patients age and vessels stiffen, there is a resulting loss of arterial compliance, the ability of the vessel to store blood volume temporarily as it is ejected with each systole. The arterial system acts like a Windkessel, or pump, as it converts intermittent flow from the heart into continuous flow to the organs. The process of stiffening occurs via vascular remodeling, a redistribution of the heterogeneous elements of the vascular wall. Endothelial dysfunction can trigger this remodeling process, increasing stiffness, raising blood pressure and pulse pressure, and ultimately leading to atherosclerosis, plaque formation, and attendant clinical events. Because angiotensin-converting enzyme inhibitors and calcium antagonists can restore arterial compliance, they are suitable choices for hypertension treatment when it is complicated by vascular stiffness.