Impact of arterial stiffening on left ventricular structure

Aging of the vasculature results in arterial stiffening and an increase in systolic and pulse pressures. Although pressure load is a stimulus for left ventricular hypertrophy, the extent to which vascular stiffening per se, i ndependent of blood pressure, influences left ventricular structure is unce rtain. Two hundred seventy-six subjects (79 normotensive and 197 otherwise healthy hypertensive individuals) underwent echocardiography to assess left ventricular structure. Arterial stiffness was estimated by the pressure-in dependent stiffness index, beta, and the pressure-dependent elastic modulus derived from simultaneous carotid ultrasound and applanation tonometry. Sy stemic arterial compliance (the inverse of stiffness) was estimated by the arterial compliance index. In multivariate analysis, beta was related to ag e (P<0.001) and smoking history (P<0.01) but not mean pressure, whereas ela stic modulus was related to age and mean pressure (both P<0.001), The arter ial compliance index was only related to age. Whereas systolic and diastoli c pressures and the elastic modulus were positively associated with left ve ntricular mass tall P<0.001), primarily because of increases in wall thickn esses, beta and the arterial compliance index bore no relation to left vent ricular mass. beta was inversely related to chamber diameter and directly r elated to left ventricular relative wall thickness, the ratio of wall thick ness to chamber radius. Younger and older hypertensive subjects had compara ble left ventricular mass, despite higher systolic and pulse pressures in t he older group, whereas older hypertensives had higher mean relative wall t hickness, associated with a significant increase in arterial stiffness (bet a, 7.06 versus 5.17; elastic modulus, 595 versus 437 dyne/cm(2) x 10(-6)) a nd reduction in the arterial compliance index (0.87 versus 1.05 mL/mm Hg pe r square meter) tall P<0.001). Thus, the extent to which arterial stiffness relates to left ventricular hypertrophy is dependent on the method by whic h arterial stiffness is estimated. Pressure-dependent methods show an assoc iation with left ventricular hypertrophy, whereas the pressure-independent stiffness index, <beta>, and the arterial compliance index are most strongl y associated with aging and left ventricular concentric remodeling but not hypertrophy.