1. What is Aortic Valve Index?

The Aortic Valve Index (AVAi) is a measurement that normalizes the aortic valve area to body surface area. It provides a more accurate assessment of aortic valve stenosis severity by accounting for patient body size.

2. How Does the Calculator Work?

The calculator uses the AVAi formula:

Where:

• \( AVA \) — Aortic Valve Area (cm²)
• \( BSA \) — Body Surface Area (m²)
• \( AVAi \) — Aortic Valve Area Index (cm²/m²)

Explanation: This calculation adjusts the aortic valve area for the patient's body size, providing a more personalized assessment of valve function.

3. Importance of AVAi Calculation

Details: AVAi is crucial for accurate diagnosis and grading of aortic stenosis, especially in patients with extreme body sizes. It helps determine the true severity of valve obstruction relative to the patient's metabolic demands.

4. Using the Calculator

Tips: Enter aortic valve area in cm² and body surface area in m². Both values must be positive numbers. BSA can be calculated using various formulas like DuBois or Mosteller.

5. Frequently Asked Questions (FAQ)

Q1: Why is AVAi important in aortic stenosis assessment?
A: AVAi accounts for body size differences, preventing underdiagnosis in large patients and overdiagnosis in small patients.

Q2: What are the normal AVAi values?
A: Normal AVAi is typically >0.85 cm²/m². Severe aortic stenosis is usually defined as AVAi <0.6 cm²/m².

Q3: How is BSA calculated?
A: BSA can be calculated using formulas like DuBois (BSA = 0.007184 × weight^0.425 × height^0.725) or Mosteller (BSA = √[height × weight / 3600]).

Q4: When is AVAi particularly useful?
A: AVAi is especially important in obese patients, very tall or short individuals, and when there's discordance between AVA and gradient measurements.

Q5: Are there limitations to using AVAi?
A: While useful, AVAi should be interpreted in clinical context along with other parameters like gradients, flow status, and symptoms.