ELASTIC PROPERTIES AND WINDKESSEL FUNCTION OF THE HUMAN AORTA
ELASTIC PROPERTIES AND WINDKESSEL FUNCTION OF THE HUMAN AORTA
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DOI：
10.1007/bf00877747
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发表时间：
1995-02-01
影响因子：
3.4
通讯作者：
BELZ, GG
中科院分区：
文献类型：
--
作者：
BELZ, GG
对主动脉弹性性质的作用的理解表明它们在心血管功能的几个部位的相关性。作为心脏后面的弹性缓冲室（Windkessel功能），主动脉和一些近端大血管在收缩期储存约50%的左心室每搏输出量。在腹主动脉瓣中，主动脉壁的弹力将这50%的体积推进到外周循环，从而产生几乎连续的外周血流。这种收缩-舒张相互作用代表了Windkessel功能，其不仅对外周循环而且对心脏有影响，导致左心室后负荷减少，冠状动脉血流和左心室舒张改善。随着年龄的增长、血压的升高和动脉粥样硬化等病理变化，主动脉对收缩期扩张的弹性阻力（或刚度）也会增加。在任何给定的平均压力下，这种增加的僵硬度导致收缩压增加和舒张压降低，收缩期血流速度增加，左心室后负荷增加，以及舒张期动脉内膜下血液供应减少，并且必须被认为是主要的病理生理因素，例如收缩期高血压。主动脉Windkessel的弹性特性可以在人体内以几种方式进行评估，最容易的是通过测量沿着主动脉的脉搏波速度。该速度越高，弹性阻力即刚度越高。其他方法依赖于评估脉压和主动脉容积变化之间的比率（Δ P/Δ V），这可以通过超声或断层摄影方法进行无创评估。所有血管硬度的评估都必须考虑当前血压的直接影响，因此对干预影响的判断依赖于血压不变。或者，为了推导出主动脉壁的“固有”刚度，必须校正血压的影响。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。血管紧张素转换酶（ACE）抑制剂和一氧化氮（NO）供体似乎直接降低了主动脉的弹性阻力。除了对血压和外周循环的其他影响外，这种影响可能具有重要的临床相关性，作为左心室卸载、改善冠状动脉循环和降低动脉系统脉动应力的额外机制。
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 (Delta 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. Angiotensin-converting enzyme (ACE) inhibitors and nitric oxide (NO) donors seem to directly reduce the elastic resistance of the aorta. This effect, in addition to other effects on blood pressure and the peripheral circulation, could have major clinical relevance as an additional mechanism for unloading the left ventricle, improving coronary circulation, and reducing the pulsatile stress of the arterial system.