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

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.

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