A hybrid approach for quantification of aortic valve stenosis using cardiac magnetic resonance imaging and echocardiography.
BACKGROUND
Doppler-derived calculation of aortic valve area (AVA) using the continuity equation can be difficult at times, e.g. due to poor acoustic windows, heavy calcification of the aortic valve, or significant flow acceleration in the left ventricular outflow tract. The aim of this study was to compare AVA as assessed by means of transthoracic echocardiography (TTE) with a hybrid approach, where the Doppler-derived numerator in the continuity equation was replaced by cardiovascular magnetic resonance (CMR) determination of stroke volume.


METHODS
Twenty consecutive patients admitted for evaluation of aortic stenosis underwent transthoracic echocardiography and CMR determination of stroke volume within a time period of 3 weeks. Additionally, continuous-wave Doppler spectra of the aortic valve were acquired immediately after the CMR examination.


RESULTS
There was no statistically significant difference for mean AVA between the two methods (0.88 +/- 0.23 cm2 by the standard continuity equation versus 0.86 +/- 0.23 cm2 by the hybrid approach, p = 0.55; r = 0.73, p < 0.01). The mean difference was 0.02 cm2 and the limits of agreement were -0.32 to 0.36. Only 2 patients were classified differently by the two methods. Intraobserver and interobserver variability and reproducibility were superior for the hybrid approach.


CONCLUSIONS
The hybrid method for determination of AVA is an excellent alternative to the standard approach by TTE.
Haghi
Dariusch
D
Medical Department, University Hospital Mannheim, Mannheim, Germany. dariush.haghi@med.ma.uni-heidelberg.de
Papavassiliu
Theano
T
Kalmar
Gabor
G
Schroder
Meike
M
Neff
Wolfgang
W
Kaden
Jens J
JJ
Muller
Ute
U
Haase
Karl K
KK
Borggrefe
Martin
M
Suselbeck
Tim
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000473:pathology*; D004452:Echocardiography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D013318:Stroke Volume