Simpson I A, Shiota T, Gharib M, Sahn D J
Wessex Regional Cardiac Unit, Southampton General Hospital, England, United Kingdom.
J Am Coll Cardiol. 1996 Feb;27(2):504-9. doi: 10.1016/0735-1097(95)00486-6.
Spatial appreciation of flow velocities using Doppler color flow mapping has led to quantitative evaluation of the zone of flow convergence proximal to a regurgitant orifice. Based on the theory of conservation of mass, geometric analysis, assuming a series of hemispheric shells of increasing velocity as flow converges on the orifice--the so-called proximal isovelocity surface area (PISA) effect--has yielded methods promising noninvasive measurement of regurgitant flow rate. When combined with conventional Doppler ultrasound to measure orifice velocity, regurgitant orifice area, the major predictor of regurgitation severity, can also be estimated. The high temporal resolution of color M-mode can be used to evaluate dynamic changes in orifice area, as seen in many pathologic conditions, which enhances our appreciation of the pathophysiology of regurgitation. The PISA methodology is potentially applicable to any restrictive orifice and has gained some credibility in the quantitative evaluation of other valve pathology, particularly mitral and tricuspid regurgitation, and in congenital heart disease. Although the current limitations of PISA estimates of regurgitation have tempered its introduction as a valuable clinical tool, considerable efforts in in vitro and clinical research have improved our understanding of the problems and limitations of the PISA methodology and provided a firm platform for continuing research into the accurate quantitative assessment of valve regurgitation and the expanding clinical role of quantitative Doppler color flow mapping.
利用多普勒彩色血流图对血流速度进行空间评估，已实现对反流口近端血流汇聚区的定量评估。基于质量守恒理论，通过几何分析，假设当血流在口处汇聚时，一系列速度不断增加的半球形壳层（即所谓的近端等速表面积（PISA）效应），已产生有望无创测量反流流速的方法。当与传统多普勒超声结合以测量口速度时，反流口面积（反流严重程度的主要预测指标）也可被估算。彩色M型的高时间分辨率可用于评估口面积的动态变化，这在许多病理情况下都可见到，从而增强了我们对反流病理生理学的认识。PISA方法可能适用于任何限制性口，并在其他瓣膜病变（特别是二尖瓣和三尖瓣反流）以及先天性心脏病的定量评估中获得了一定的可信度。尽管目前PISA对反流的估计存在局限性，限制了其作为一种有价值的临床工具的应用，但体外和临床研究中的大量努力增进了我们对PISA方法问题和局限性的理解，并为继续研究瓣膜反流的准确定量评估以及定量多普勒彩色血流图不断扩大的临床作用提供了坚实的平台。
