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Titolo:
Smooth muscle relaxation and local hydraulic impedance properties of the aorta
Autore:
Cholley, BP; Lang, RM; Korcarz, CE; Shroff, SG;
Indirizzi:
Univ Pittsburgh, Dept Bioengn, Pittsburgh, PA 15261 USA Univ Pittsburgh Pittsburgh PA USA 15261 Bioengn, Pittsburgh, PA 15261 USA Univ Chicago, Dept Med, Cardiol Sect, Chicago, IL 60637 USA Univ Chicago Chicago IL USA 60637 ed, Cardiol Sect, Chicago, IL 60637 USA
Titolo Testata:
JOURNAL OF APPLIED PHYSIOLOGY
fascicolo: 6, volume: 90, anno: 2001,
pagine: 2427 - 2438
SICI:
8750-7587(200106)90:6<2427:SMRALH>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
AUTOMATIC BOUNDARY DETECTION; PRESSURE-DIAMETER RELATION; ESSENTIAL-HYPERTENSION; ELASTIC PROPERTIES; CONSCIOUS DOGS; ANTIHYPERTENSIVE TREATMENT; ARTERIAL-HYPERTENSION; ONLINE ASSESSMENT; BLOOD-PRESSURE; NIFEDIPINE;
Keywords:
compliance; incremental elastic modulus; characteristic impedance; pulse wave velocity; calcium channel blocker;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
49
Recensione:
Indirizzi per estratti:
Indirizzo: Shroff, SG Univ Pittsburgh, Dept Bioengn, 749 Benedum Hall, Pittsburgh, PA15261 USA Univ Pittsburgh 749 Benedum Hall Pittsburgh PA USA 15261 61 USA
Citazione:
B.P. Cholley et al., "Smooth muscle relaxation and local hydraulic impedance properties of the aorta", J APP PHYSL, 90(6), 2001, pp. 2427-2438

Abstract

Smooth muscle relaxation is expected to yield beneficial effects on hydraulic impedance properties of large vessels. We investigated the effects of intravenous diltiazem infusion on aortic wall stiffness and local hydraulic impedance properties. In seven anesthetized, closed-chest dogs, instantaneous cross-sectional area and pressure of the descending thoracic aorta were measured using transesophageal echocardiography combined with acoustic quantification and a micromanometer, respectively. Data were acquired during a vena caval balloon inflation, both at the control condition and with diltiazem infusion. At the operating point, diltiazem reduced blood pressure in all dogs but did not alter aortic dimensions or wall stiffness. Over the observed pressure range, aortic area-pressure relationships were linear. Whereas diltiazem affected the slope of this relationship variably (no change in3 dogs, increase in 1 dog, decrease in 3 dogs), the zero-pressure area intercept was significantly increased in every case such that higher area was observed at any given pressure. When comparisons were made at a common level of wall stress, wall stiffness was either increased or unchanged during diltiazem infusion. In contrast, diltiazem decreased wall stiffness in everycase when comparisons were made at a common level of aortic midwall radius. Aortic characteristic impedance and pulse wave velocity, components of left ventricular hydraulic load that are determined by aortic elastic and geometric properties, were affected variably. A comparison of wall stiffness at matched wall stress appears inappropriate for assessing changes in smoothmuscle tone. Because of the competing effects of changes in vessel diameter and wall stiffness, smooth muscle relaxation is not necessarily accompanied by the expected beneficial changes in local aortic hydraulic impedance. These results can be reconciled by recognizing that components other than vascular smooth muscle (e.g., elastin, collagen) contribute to aortic wall stiffness.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/03/20 alle ore 01:57:11