Aortic Valve Area Calculator

Created by Joanna Michałowska, PhD candidate
Reviewed by Dominik Czernia, PhD and Jack Bowater
Last updated: Nov 25, 2022

Aortic valve area calculator (AVA calculator) allows you to indirectly determine someone's aortic valve area. You can use it to evaluate the severity of aortic stenosis.

Read the article below to get familiar with the aortic valve area formula and reference values for this measurement.

Aortic valve area

The aortic valve is a valve found in the human heart. It is located between the left ventricle and the aorta, and this is the last structure in the heart blood flows through before it enters systematic circulation. When the left ventricle contracts, the pressure rises in the left ventricle, and once it is above the pressure in the aorta, the aortic valve to open and allows blood flow into the aorta and thereby into the rest of the body.

Here you can find the most important information regarding aortic valve area:

  • Estimating the area of aortic valve can be used to evaluate the severity of aortic stenosis.
  • If aortic valve area is less than 1 cm21\ \text{cm}^2 (0.155 in20.155\ \text{in}^2), it indicates severe aortic stenosis.
  • We can classify aortic valve area as normal if it is in the 3 cm23\ \text{cm}^2 - 4 cm24\ \text{cm}^2 (0.465 in20.465\ \text{in}^2 - 0.62 in20.62\ \text{in}^2) range.

What is aortic stenosis?

Aortic stenosis is a narrowing of the aortic valve opening. This is one of the most common and serious valve disease problems. This condition is associated with the restriction of the blood flow from the left ventricle to the aorta, which can also affect the pressure in the left atrium. A lot of patients with aortic stenosis does not experience any symptoms, however, if the blood flow is greatly reduced, the manifestation of the disease may include:

  • Chest pains;
  • Rapid heartbeat;
  • Shortness of breath;
  • Difficulty in walking short distances (a factor you can assess with our 6 minute walk test calculator);
  • Swollen feet; and
  • Reduction in physical activity.

There are different ways of treating aortic stenosis, including medications, valve repair, or valve replacement.

If you want to know more about aortic stenosis, check the American Heart Association website.

How to calculate aortic valve area - aortic valve area formula

Below, we present an aortic valve area formula:
,

AVA=LVOT2 ⁣× ⁣0.7854 ⁣× ⁣VT1VT2\text{AVA} = \frac{\text{LVOT}^2\! \times\! 0.7854 \!\times \!V_{\text{T}_1}}{V_{\text{T}_2}}

where:

  • AVA\text{AVA} - Aortic valve area in cm2\text{cm}^2;

  • LVOT\text{LVOT} - Left ventricular outflow tract diameter, in cm\text{cm};

  • VT1V_{\text{T}_1} - Subvalvular velocity time integral, in cm\text{cm}; and

  • VT2V_{\text{T}_2} - Maximal velocity time integral across the valve, in cm\text{cm}.

Using relevant parameters, we don't calculate the surface area directly from geometric measurements!

Normal aortic valve area - reference values

The table below shows reference values for aortic valve area. As you can see, the normal aortic valve area is equal to 3 cm23\ \text{cm}^2 - 4 cm24\ \text{cm}^2 (0.465 in20.465\ \text{in}^2 - 0.62 in20.62\ \text{in}^2).

AVA\boldsymbol{\text{AVA}} (cm2)\text{cm}^2)

Aortic Stenosis Severity

<1<1

Severe

11 - 1.51.5

Moderate

1.51.5 - 33

Mild

>3>3

Normal

🙋 If you heart is set on the circulatory system, why not visit our other related tools, like the heart rate calculator, the HEART score calculator, or the EROA mitral regurgitation calculator, another valvular disease?

Aortic valve area calculator (AVA calculator), a practical example

Now you know how to calculate aortic valve area. But how to do it using our aortic valve calculator? It is really easy!

You will need three values to perform the calculations:

  • LVOT\text{LVOT} - Left ventricular outflow tract diameter;
  • VT1V_{\text{T}_1} - Subvalvular velocity time integral; and
  • VT2V_{\text{T}_2} - Maximal velocity time integral across the valve.

Let's assume that for our exemplary patient those values are equal to 2.5 cm2.5\ \text{cm}, 25 cm25\ \text{cm}, and 50 cm50\ \text{cm}, respectively.
The equation will look like this:

AVA=LVOT2 ⁣× ⁣0.7854 ⁣× ⁣VT1VT2=2.52×0.7854×2550=122.7250=2.45 cm2\begin{split} \text{AVA} &= \frac{\text{LVOT}^2\! \times\! 0.7854 \!\times \!V_{\text{T}_1}}{V_{\text{T}_2}}\\ \\[1.5 em] &=\frac{2.5^2\times0.7854\times 25}{50}\\ \\[1.5 em] &=\frac{122.72}{50}\\ \\[1.5 em] & = 2.45\ \text{cm}2 \end{split}

As you can see, this value is not within the normal aortic valve area range. This patient has mild aortic stenosis.

Joanna Michałowska, PhD candidate
LVOT
mm
VTI₁
cm
VTI₂
cm
Aortic Valve Area (AVA)
cm²
AVA (cm²)Aortic Stenosis Severity
< 1Severe
1 - 1.5Moderate
1.5 - 3Mild
> 3Normal
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