Aortic Valve Area by Continuity Equation (VTI)

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Data Acquisition

aortic valve area by VTI

Reference Values

Aortic Stenosis Severity
Mild Moderate Severe
AVA (cm2) >1.5 1.0-1.5 <1.0
AVA Index (cm2/m2) >0.85 0.60-0.85 <0.6


\[ AVA = \frac{\pi \times (LVOT/2)^2 \times VTI_{LVOT}}{VTI_{AV}} \]


VTI Velocity-time integral
LVOT Left ventricular outflow tract diameter
AV Aortic valve
AVA Aortic valve area
BSA Body surface area using the Mosteller formula


1. Baumgartner H, et al. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr. 2009 Jan;22(1):8,10. Full text


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Developer & Illustrator: Sirikarn Napan, MD, FACC