Aortic Valve Index Calculator

Aortic Valve Index Formula:

\[ AVI = \frac{Stroke\ Volume}{\sqrt{LVOT\ Area \times VTI_{lvot}}} \quad \text{or} \quad DVI = \frac{V_{aortic}}{V_{lvot}} \]

Aortic Valve Index (AVI):

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1. What is Aortic Valve Index?

The Aortic Valve Index (AVI) is a dimensionless index used to assess aortic valve area and function. It provides valuable information about valve stenosis and helps in evaluating the severity of aortic valve disease.

2. How Does the Calculator Work?

The calculator uses the AVI formula:

\[ AVI = \frac{Stroke\ Volume}{\sqrt{LVOT\ Area \times VTI_{lvot}}} \]

Where:

\( Stroke\ Volume \) — Volume of blood pumped per heartbeat (mL)
\( LVOT\ Area \) — Left ventricular outflow tract area (cm²)
\( VTI_{lvot} \) — Velocity time integral of LVOT (cm)

Explanation: The AVI provides a dimensionless assessment of aortic valve function, with lower values indicating more severe stenosis.

3. Importance of AVI Calculation

Details: AVI is crucial for diagnosing aortic stenosis severity, guiding treatment decisions, and monitoring disease progression in patients with valvular heart disease.

4. Using the Calculator

Tips: Enter stroke volume in mL, LVOT area in cm², and VTI LVOT in cm. All values must be positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the normal range for AVI?
A: Normal AVI values typically range from 0.8-1.2 cm³/m², with values below 0.8 suggesting significant stenosis.

Q2: How does AVI differ from AVA?
A: AVI is a dimensionless index, while AVA (Aortic Valve Area) provides the actual anatomical area. AVI is less dependent on body size.

Q3: When is AVI calculation most useful?
A: AVI is particularly valuable in cases of low-flow, low-gradient aortic stenosis and for patients with small body surface area.

Q4: What are the limitations of AVI?
A: AVI may be less accurate in patients with irregular heart rhythms, significant mitral regurgitation, or poor echocardiographic windows.

Q5: How often should AVI be measured?
A: Frequency depends on clinical context, but typically during initial evaluation and follow-up visits for patients with known aortic valve disease.