Aortic Valve Area Calculator

Estimate Aortic Valve Area

The aortic valve area (AVA) calculator uses the continuity equation to estimate how wide the aortic valve opens during echocardiography. Clinicians use AVA to grade aortic stenosis severity when direct planimetry is unavailable. Enter left ventricular outflow tract (LVOT) diameter and the subvalvular and valvular velocity time integrals to get AVA in cm² with severity interpretation.

Continuity Equation Formula

$$\text{AVA} = \dfrac{\text{LVOT}^2 \times 0.7854 \times V_{T_1}}{V_{T_2}}$$

LVOT is the outflow tract diameter in centimeters. The constant 0.7854 equals π/4 and converts diameter to cross-sectional area. VT1 is the subvalvular velocity time integral and VT2 is the maximal velocity time integral across the aortic valve, both in centimeters. For related cardiovascular assessments, see the Max Heart Rate Calculator and 6 Minute Walk Test Calculator.

Interpreting AVA Results

An AVA below 1 cm² indicates severe aortic stenosis. Values from 1 to 1.5 cm² suggest moderate disease, 1.5 to 3 cm² mild narrowing, and above 3 cm² a normal valve area. Always correlate AVA with symptoms, valve gradients, and left ventricular function rather than relying on a single measurement.