1. What is the Aortic Valve Equation?

The Aortic Valve Equation calculates the aortic valve area using the continuity equation. It's commonly used in echocardiography to assess the severity of aortic stenosis by comparing the left ventricular outflow tract (LVOT) with the aortic valve flow.

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 at the LVOT (cm)
• VTI_AoV — Velocity time integral at the aortic valve (cm)

Explanation: The equation is based on the principle of continuity of flow, where the stroke volume at the LVOT equals the stroke volume at the aortic valve.

3. Importance of Aortic Valve Area Calculation

Details: Accurate aortic valve area calculation is crucial for diagnosing and grading the severity of aortic stenosis, which helps determine the need for valve replacement.

4. Using the Calculator

Tips: Enter LVOT Area in cm², VTI values in cm. All values must be positive numbers. Typical LVOT area is about 3-4 cm² in adults.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal aortic valve area?
A: Normal aortic valve area is 3-4 cm². Severe aortic stenosis is typically <1.0 cm².

Q2: How is LVOT area determined?
A: LVOT area is calculated as π × (LVOT diameter/2)², measured from the parasternal long-axis view.

Q3: What are typical VTI values?
A: Normal LVOT VTI is 18-22 cm, while aortic valve VTI depends on stenosis severity (higher in severe stenosis).

Q4: When is this calculation most useful?
A: It's particularly valuable in low-flow, low-gradient aortic stenosis cases.

Q5: Are there limitations to this method?
A: Accuracy depends on proper measurement technique and assumes circular LVOT geometry.