AV Velocity Ratio
AVA (Continuity Eqn VTI)
AVA (Continuity Eqn VMax)
dP/dt (LV Contractility)
dP/dt (RV Contractility)
Left Atrial Pressure (MR)
Aortic Valve Area (Continuity Equation using VMax)
Author: Dr. Chi-Ming Chow, Updated: January 1st, 2011
Author: Dr. Chi-Ming Chow, Updated: January 1st, 2011
CalculationInputV1
V2
LVOT
Height
Weight
ResultAVA
AVA Index
Calculate
Clear
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InformationAVA = (π × (LVOT / 2)2 × V1) / V2
AVA Index = AVA / BSA
AVA Index = AVA / BSA
Aortic valve area can be calculated by using the principle of conservation of mass — "What comes in must go out". Although VTI is a more accurate method, using maximum velocities is simpler and can generate a very close result. The simplified continuity equation is based on the concept that in native aortic valve stenosis the shape of the velocity curve in the outflow tract and aorta is similar so that the ratio of LVOT to aortic jet VTI is nearly identical to the ratio of the LVOT to aortic jet maximum velocity (V).
Aortic valve area indexed to body surface area should be considered for the large and small extremes of body surface area.
References| Baumgartner H, et al. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr. 2009 Jan;22(1):6-8,10. |  |
| Baumgartner H, et al. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr. 2009 Jan;22(1):6-8,10. | |
