1. What is Aortic Valve Area (AVA)?

The Aortic Valve Area (AVA) calculation is used to assess the severity of aortic valve stenosis. It measures the effective area of the aortic valve opening, which helps determine if the valve is narrowed and to what degree.

2. How Does the Calculator Work?

The calculator uses the continuity equation:

Where:

• \( LVOT\ Area \) — Left ventricular outflow tract area (cm²)
• \( VTI_{LVOT} \) — Velocity time integral of the LVOT (cm)
• \( VTI_{AV} \) — Velocity time integral across the aortic valve (cm)

Explanation: The equation is based on the principle of continuity, which states that the flow volume proximal to the valve must equal the flow volume through the valve.

3. Importance of AVA Calculation

Details: AVA measurement is crucial for diagnosing and grading the severity of aortic stenosis, which helps guide treatment decisions including valve replacement.

4. Using the Calculator

Tips: Enter LVOT Area in cm², VTI LVOT in cm, and VTI AV in cm. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are normal AVA values?
A: Normal aortic valve area is 3-4 cm². Severe aortic stenosis is typically defined as AVA <1.0 cm².

Q2: How is LVOT Area determined?
A: LVOT Area is calculated as π × (LVOT diameter/2)², measured by echocardiography.

Q3: What are the limitations of this calculation?
A: Accuracy depends on proper measurement technique and assumes circular geometry of the LVOT.

Q4: When is this calculation most useful?
A: Particularly valuable when there's discordance between gradient and ejection fraction in aortic stenosis assessment.

Q5: How does this relate to valve gradients?
A: AVA provides complementary information to transvalvular gradients in assessing stenosis severity.