Richards K L
Department of Medicine, University of New Mexico School of Medicine, Albuquerque 87131.
Circulation. 1991 Sep;84(3 Suppl):I182-7.
Doppler and imaging echocardiography are highly useful methods of identifying and quantifying both aortic and pulmonic stenosis. The presence of valve stenosis and associated regurgitation is based on detecting abnormal intracardiac velocity patterns near the affected valve. Defining the specific valve involved and the type of lesion present is based on determining the location and timing of the abnormal velocities. Both color flow imaging and duplex pulsed Doppler with two-dimensional echocardiographic imaging are highly accurate in identifying the lesions present. Quantification of the severity of stenotic lesions requires calculation of the pressure gradient across the valve and estimation of valve area; quantification of volume flow rate is frequently helpful. The pressure gradient is calculated from high velocity data acquired in the stenotic valve orifice by using the Bernoulli equation. Volume flow rate through the valve can be estimated by using Doppler velocity data and two-dimensional echocardiographic imaging data acquired at sites upstream from the stenotic valve. The continuity equation allows calculation of valve area that is based on this noninvasive stroke volume and pressure gradient data. This review characterizes flow patterns present near stenotic valves, discusses the equations required to quantify aortic and pulmonic stenosis, and then describes the clinical approach to the noninvasive quantification of both stenotic lesions.
多普勒超声心动图和成像超声心动图是识别和量化主动脉瓣狭窄及肺动脉瓣狭窄的非常有用的方法。瓣膜狭窄及相关反流的存在是基于检测受影响瓣膜附近的异常心内速度模式。确定具体受累瓣膜及现存病变类型是基于确定异常速度的位置和时间。彩色血流成像和二维超声心动图的双功脉冲多普勒在识别现存病变方面都高度准确。狭窄病变严重程度的量化需要计算跨瓣膜的压力阶差并估计瓣膜面积；流量率的量化通常也有帮助。压力阶差是通过使用伯努利方程从狭窄瓣膜口获取的高速数据计算得出的。通过瓣膜的流量率可利用多普勒速度数据和在狭窄瓣膜上游部位获取的二维超声心动图成像数据来估计。连续性方程可根据这种无创的每搏输出量和压力阶差数据计算瓣膜面积。本综述描述了狭窄瓣膜附近的血流模式，讨论了量化主动脉瓣狭窄和肺动脉瓣狭窄所需的方程，然后描述了对两种狭窄病变进行无创量化的临床方法。
