ENDOTHELIAL CONTROL OF ARTERIAL DISTENSIBILITY IS IMPAIRED IN CHRONICHEART-FAILURE

Background Vascular tone is a determinant of conduit artery distensibi lity. The aim of this study was to establish whether endothelium-deriv ed relaxing factor (EDRF) influences the distensibility of conduit art eries and whether endothelium-mediated increases in distensibility are impaired in chronic heart failure (CHF). Methods and Results Conduit artery distensibility was measured by two methods in healthy subjects and in nine patients with CHF caused by dilated cardiomyopathy. In the first method, pulse-wave velocity (PWV) was measured in the right com mon iliac artery at rest and during local infusions of acetylcholine ( 10(-7) to 10(-5) mol/L) or adenosine (2X10(-7) to 2x10(-5) mol/L), wit h correction for systemic effects. Acetylcholine induced concentration -dependent local reductions of PWV in healthy subjects (-5%, -15%, and -26%) but not in CHF patients (3%, 1%, -4%, P<.01), whereas adenosine induced similar reductions of PWV in healthy subjects and CHF patient s. In the second method, brachial artery diameter, blood flow, and blo od pressure were measured noninvasively by high-resolution ultrasound, continuous-wave Doppler, and photoplethysmography during reactive hyp eremia in the hand and after sublingual glyceryl trinitrate (GTN, 400 mu g). Hyperemic flow, similar in healthy subjects and CHF patients, w as associated with increases in diameter and distensibility in healthy subjects (8.8% and 18.4%, respectively) but not in CHF patients (0.3% and -4.5%), whereas GTN induced similar effects in healthy subjects a nd CHF patients. Conclusions These data indicate that conduit artery d istensibility is increased by acetylcholine and increased blood flow i n healthy subjects but not in CHF patients, whereas the effects of ade nosine and GTN on distensibility are preserved in CHF patients. This i mplies that EDRF-mediated increases in distensibility are impaired in CHF patients, thus adding to cardiac work.