The Brachial-Ankle Pulse Wave Velocity Is a Better Predictor for Pulse Pressure than Augmentation Index in Older Hypertensives

The brachial-ankle pulse wave velocity (PWV) is a new measure for arterial stiffness. The relative contribution of systemic arterial stiffness and wave reflection to the genesis of pulse pressure remains unclear. To address this issue, we measured blood pressure, heart rate, brachial-ankle PWV, and augmentation index (AI) of the left common carotid artery in young and older hypertensives before and after sublingual administration of nitroglycerin, using a new automatic device. Pulse pressure was larger and brachial-ankle PWV and AI were significantly higher in the older than in the younger group. Both brachial-ankle PWV and AI were significantly and positively correlated with pulse pressure in the older group. In multiple regression analysis, the brachial-ankle PWV was an independent contributor for pulse pressure, but AI was not. Nitroglycerin significantly lowered mean blood pressure in both groups but reduced pulse pressure only in the older group. Nitroglycerin similarly reduced AI in the two groups but reduced the brachial-ankle PWV by about 74% more in the older group. The change in pulse pressure after nitroglycerin was significantly correlated with that in brachial-ankle PWV (r0.384, P0.00005) but not with that in AI in the old group. Both heart rate and left ventricular ejection time were similar for either condition. These data suggest that increased systemic arterial stiffness, but not wave reflection, plays a prime role in the regulation of pulse pressure in older hypertensive patients. Expected reduction in pulse pressure after nitroglycerin is possibly offset by an aortic mechanism in young hypertensives.