Arterial mechanical properties in dilated cardiomyopathy. Aging and the response to nitroprusside.

Abstract

The effects of aging on arterial mechanical properties and the response to nitroprusside were examined in 25 patients with dilated cardiomyopathy. High-fidelity pressures were recorded with a multisensor catheter. Pulse wave velocity was determined between two sensors in the thoracic aorta. Arterial compliance was determined by an analysis of the diastolic waveform and cardiac output.At baseline, despite a similar systemic vascular resistance, the pulsatile load (e.g., arterial compliance) and wave transmission characteristics (e.g., pulse wave velocity) were altered with aging. Arterial compliance was reduced in older (> 50 yr, n = 8) versus younger (< 35 yr, n = 8) patients (0.51±0.17 vs.1.33±0.63 ml/mmHg, P < 0.01) and intermediate in those 35-50 yr of age (n = 9,0.72±0.40 ml/mmHg). There was a positive correlation between age and pulse wave velocity (r = +0.90).Nitroprusside infusion decreased resistance, increased arterial compliance, and lowered pulse wave velocity in all groups. Yet, advancing age was associated with a greater fall in wave velocity for a given fall in aortic pressure. The slope (K) of the relation between pulse wave velocity and aortic diastolic pressure progressively increased with age (0.01±0.03, 0.06±0.02, and 0.09±0.03 m/s-mmHg). Multiple linear regression analysis revealed a significant relation between K and age.These data demonstrate that in older patients with dilated cardiomyopathy the left ventricle is coupled to an arterial circulation that has a greater pulsatile load, despite a similar steady load. Furthermore, these age-related changes in the arterial system affect the hemodynamic response to pharmacologicallyinduced vasodilatation. (J. Clin.

Aortic Diameter, Aortic Stiffness, and Wave Reflection Increase With Age and Isolated Systolic Hypertension

“…No direct effect on aortic stiffness has been found for nitrates in older human adults. [55][56][57] In very carefully controlled experimental studies on animals, nitrates have shown no direct effect on aortic characteristic impedance, despite marked effect on peripheral muscular arteries. 58 In contrast to inefficacy on aortic stiffness, nitrates and other arterial dilators have marked effects on wave reflection and can virtually eliminate the late systolic augmentation Figure 5.…”

Isolated systolic hypertension, pulse pressure, and arterial stiffness as risk factors for cardiovascular disease

“…Passive reduction in distending pressure can reduce aortic stiffness to a modest degree [2,31], but although data to the contrary exist [2,32], vasodilator drugs generally appear to have little direct beneficial effect. In contrast, the indirect effects of arterial stiffness can be offset to a substantial degree through reduction of wave reflection with vasodilator drugs that act on peripheral arteries and arterioles [2,26] (Fig.…”

Brachial Artery Elastic Mechanics in Patients With Heart Failure

“…These details are important because each of these factors can influence arterial mechanical properties. [31][32][33] In particular, arterial size (which correlates fairly tightly with measures such as height and forearm volume) is a major determinant of mechanical properties, such as compliance and PWV, 20 independent of vessel stiffness.…”