Doppler-derived aortic valve gradients: imaging versus non-imaging techniques.
BACKGROUND
Quantitative Doppler echocardiography has become an established method for estimating aortic valve area in aortic stenosis, replacing cardiac catheterization as the confirmatory study. The technique is time consuming, especially when measuring the transaortic velocity, which is performed by convention. This is accomplished by interrogating multiple windows with a non-imaging probe to record the maximal velocity. To determine how the examination could be expedited, we prospectively compared aortic valve gradients measured by Pedof and duplex transducers.


METHODS
One hundred eighty-two consecutive patients with native aortic valve disease, mechanical or bioprosthetic aortic valves were studied. Two technicians measured maximal transaortic valve velocities from apical, subcostal, right parasternal and suprasternal notch windows with a 2 MHz Pedof probe and from the apical window with a 3-3.5 MHz duplex probe using color flow to orient the continuous wave beam. Angle-corrected and non-angle-corrected signals were recorded. There were 109 comparisons read by two observers; intra- and inter-reader variations were 0.4% and 2.0%, respectively.


RESULTS
Duplex imaging velocity gradients were consistently smaller than Pedof non-imaging measurements with a mean +/- 1 standard deviation difference between peak velocities of 0.40 +/- 0.71 meters per second (m/s) for angle-corrected, and 0.76 +/- 0.68 for non-angle-corrected signals (both p < 0.001). Technician variability accounted for some of the difference (p < 0.02).


CONCLUSIONS
Although non-imaging and imaging methods share the apical window, the Pedof probe scans unlimited planes to locate the maximal aortic valve gradient, whereas the duplex probe is confined to the plane providing the optimal two-dimensional image. Therefore, Doppler echocardiographic estimations of aortic valve areas still require careful, time-intensive non-imaging recordings of transaortic velocities.
Tavli
T
T
Section of Cardiology, Aegean University, Izmir, Turkey.
Ammar
A
A
Wong
M
M
D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D001705:Bioprosthesis; D001783:Blood Flow Velocity / Q000502:physiology; D015150:Echocardiography, Doppler / Q000295:instrumentation*; D006350:Heart Valve Prosthesis; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008838:Microcomputers; D015588:Observer Variation; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014159:Transducers