Publication Date
2-1-2015
Journal
The Texas Heart Journal
DOI
10.14503/THIJ-13-3635
PMID
25873793
Publication Date(s)
February 2015
Language
English
PMCID
PMC4378036
PubMedCentral® Posted Date
2-1-2015
PubMedCentral® Full Text Version
Post-Print
Published Open-Access
yes
Keywords
Aortic valve/anatomy & histology, aortic valve stenosis/physiopathology, cardiac output, echocardiography, transesophageal/methods/standards, evaluation studies as topic, heart valve diseases/diagnosis/ultrasonography, predictive value of tests, severity of illness index, ventricular outflow obstruction/ultrasonography
Copyright
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Abstract
Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined.
In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area.
We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm2) was underestimated by the standard method (1.05 ± 0.47 cm2; P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape.
More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index.