Author + information
- Received December 19, 1994
- Revision received September 22, 1995
- Accepted September 27, 1995
- Published online February 1, 1996.
- Iain A. Simpson, MD,FRCP,FACCc,
- Takahiro Shiota, MD,PhD*,
- Morteza Gharib, PhD† and
- David J. Sahn, MD,FACC1,*
- ↵1Address for correspondence: Dr. David J. Sahn, Center for Congenital Heart Disease, UHN 60, Oregon Health Sciences University, 3181 W Sam Jackson Park Road, Portland, Oregon 97201-3098.
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 severit, 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.
This study was supported in part by Grant HL43287 from the National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland.
- Received December 19, 1994.
- Revision received September 22, 1995.
- Accepted September 27, 1995.