Peripheral Pulse Pressure, Large Arteries, and Microvessels

he aorta is a capacitance vessel that enables transformation of the "on-off" blood-flow characteristics of the left ventricle into a less pulsatile flow in more distal vessels. Thus, a smooth nonpulsatile blood-flow pattern is achieved at capillary level. Arterial wall stiffness determines the degree of energy absorbed by the elastic aorta and its recoil in diastole. Aortic pulse pressure (PP) in health is physiologically lower than peripheral PP. Reduction of elevated aortic systolic blood pressure (SBP) protects circulation from pressure-induced damage. Maintaining aortic diastolic blood pressure (DBP) ensures adequate coronary perfusion. A stiffer aorta, which can be observed with aging and in different pathological conditions such as hypertension, obesity, diabetes mellitus, and dyslipidemia, fails in both of these tasks. Numerous studies now show that PP, arterial stiffness, and early wave reflections are strong predictors of cardiovascular (CV) risk. The downward consequences of enhanced pulsatility, particularly at the peripheral and even the microvascular levels, are less documented. The study by Mitchell et al 2 in the June issue of Hypertension addresses this subject, with particular focus on a healthy elderly population.