Belz G G
Zentrum für Kardiovaskuläre Pharmakologie, Mainz-Wiesbaden, Germany.
Cardiovasc Drugs Ther. 1995 Feb;9(1):73-83. doi: 10.1007/BF00877747.
An understanding of the role of the aortic elastic properties indicates their relevance at several sites of cardiovascular function. Acting as an elastic buffering chamber behind the heart (the Windkessel function), the aorta and some of the proximal large vessels store about 50% of the left ventricular stroke volume during systole. In diastole, the elastic forces of the aortic wall forward this 50% of the volume to the peripheral circulation, thus creating a nearly continuous peripheral blood flow. This systolic-diastolic interplay represents the Windkessel function, which has an influence not only on the peripheral circulation but also on the heart, resulting in a reduction of left ventricular afterload and improvement in coronary blood flow and left ventricular relaxation. The elastic resistance (or stiffness), which the aorta sets against its systolic distention, increases with aging, with an increase in blood pressure, and with pathological changes such as atherosclerosis. This increased stiffness leads to an increase in systolic blood pressure and a decrease in diastolic blood pressure at any given mean pressure, an increase in systolic blood velocity, an increase in left ventricular afterload, and a decrease in subendocardial blood supply during diastole, and must be considered a major pathophysiological factor, for example, in systolic hypertension. The elastic properties of the aortic Windkessel can be assessed in vivo in humans in several ways, most easily by measuring the pulse wave velocity along the aorta. The higher this velocity, the higher the elastic resistance, that is, the stiffness. Other methods depend on assessment of the ratio between pulse pressure and aortic volume changes (delata P/delta V), which can be assessed noninvasively by ultrasonic or tomographic methods. All assessments of vessel stiffness have to take into account the direct effect of current blood pressure, and thus judgements about influences of interventions rely on an unchanged blood pressure. Alternatively, to derive the "intrinsic" stiffness of the aortic wall one has to correct for the effect of the blood pressure present. Recently reports about pharmacologic influences on the elastic properties of the aorta have emerged in the literature.(ABSTRACT TRUNCATED AT 400 WORDS)
对主动脉弹性特性作用的理解表明其在心血管功能的多个部位具有相关性。主动脉和一些近端大血管作为心脏后方的弹性缓冲腔（风箱功能），在收缩期储存约50%的左心室搏出量。在舒张期，主动脉壁的弹力将这50%的血量输送到外周循环，从而形成几乎连续的外周血流。这种收缩 - 舒张相互作用代表了风箱功能，它不仅对外周循环有影响，对心脏也有影响，导致左心室后负荷降低，冠状动脉血流和左心室舒张得到改善。主动脉抵抗其收缩期扩张的弹性阻力（或硬度）会随着年龄增长、血压升高以及诸如动脉粥样硬化等病理变化而增加。这种硬度增加会导致在任何给定平均压力下收缩压升高和舒张压降低、收缩期血流速度增加、左心室后负荷增加以及舒张期心内膜下血液供应减少，并且必须被视为例如收缩期高血压的主要病理生理因素。主动脉风箱的弹性特性可以通过多种方式在人体活体中进行评估，最简便的方法是测量沿主动脉的脉搏波速度。该速度越高，弹性阻力即硬度越高。其他方法依赖于评估脉压与主动脉容积变化的比率（ΔP/ΔV），这可以通过超声或断层扫描方法进行无创评估。所有血管硬度评估都必须考虑当前血压的直接影响，因此关于干预影响的判断依赖于血压不变。或者，为了得出主动脉壁的“内在”硬度，必须校正当前存在的血压影响。最近文献中出现了关于药物对主动脉弹性特性影响的报道。（摘要截断于400字）
