Author + information
- Received January 30, 1988
- Revision received June 2, 1988
- Accepted June 18, 1988
- Published online March 1, 1989.
- Robert A. Levine, MD, FACCa,1,
- A. Jimoh, MS†,
- Edward G. Cape, BSCHE†,
- Scott McMillan, PhD†,
- Ajit P. Yoganathan, PhD† and
- Arthur E. Weyman, MD, FACCa
- ↵1Address for reprintsRobert A. Levine, MD, Cardiac Ultrasound Laboratory, Phillips House 8, Massachusetts General Hospital. Boston, Massachusetts 02114.
Doppler ultrasound is currently being widely applied to measure intracardiac pressure gradients noninvasively. In comparative invasive studies, it is generally assumed that pressure is effectively uniform distal to the stenosis. As the poststenotic jet expands, however, its velocity decreases, and pressure is recovered to the extent permitted by turbulence, so that the measured gradient will be lower if the distal catheter is positioned downstream from the vena contracta. This can lead to apparent Doppler “overestimation” of the pressure gradient because of this phenomenon of pressure recovery.
This study demonstrates that pressure recovery can be important in a variety of clinical settings studied by in vitro models. Although most prominent in streamlined tunnels modeled after the obstruction in patients with hypertrophic cardiomyopathy, these effects are important even for central stenoses at physiologic flow rates. Because precise catheter position is not always known or controlled, these findings suggest an important advantage for Doppler gradient estimation, because it provides the maximal gradient at the vena contracta, which determines the load on the proximal chamber.
☆ Parts I and 11 of this Seminar appeared in the November 1988 and January 1989 issues of the Journal, respectively.
☆☆ This work was performed during the tenure of a Clinician-Scientist Award of the American Heart Association with funds contributed by its Massachusetts Affiliate and was supported by a grant from the Whitaker Foundation, Camp Hill, Pennsylvania; by Grant HL-38176 from the National Institutes of Health, Bethesda, Maryland and by a grant from the American Heart Association, Dallas, Texas.
- Received January 30, 1988.
- Revision received June 2, 1988.
- Accepted June 18, 1988.