Circulation, Vol 69, 1177-1181, Copyright © 1984 by American Heart Association
LM Valdes-Cruz, S Horowitz, DJ Sahn, D Larson, C Oliveira Lima and E Mesel
The purpose of this study was to develop an open-chest animal preparation
to validate the accuracy of a two-dimensional Doppler echocardiographic
method for estimating pressure drops across discrete stenotic obstructions.
Six mongrel dogs underwent median sternotomy and catheters were placed in
the right ventricle, distal main pulmonary artery, and aorta of each. A 1/8
inch umbilical tape was sewn to the posterior rim of the pulmonary artery
just above the anulus and was progressively tightened to vary the degree of
stenosis. Ultrasound and Doppler studies were performed with a 2.5 MHz
phased-array unit with capabilities for pulsed or continuous-mode Doppler
and real-time imaging. Peak systolic main pulmonary arterial flow
velocities were recorded by Doppler echocardiography within the jet distal
to the band from an oblique parasternal short-axis echocardiographic view
and corrected for angle of incidence between the direction of Doppler
sampling and the presumed direction of flow. Doppler velocities were
converted to gradients with a simplification of the Bernoulli equation
(gradient = 4 X maximal Doppler flow velocity2 ). Maximal Doppler-
determined systolic pulmonary arterial velocities showed a good linear
correlation with the 63 measured pressure drops (r = .95, SEE +/- 36.3
cm/sec). An excellent correlation was also found between Doppler-
calculated and actual pressure gradients (r = .96, SEE +/- 7.26 mm Hg). Our
results suggest that this Doppler method for measuring gradients across
discrete stenotic obstructions may be quite accurate in clinical
applications.
ARTICLES
Validation of a Doppler echocardiographic method for calculating severity of discrete stenotic obstructions in a canine preparation with a pulmonary arterial band
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