Aortic Valve EOA Calculator Life Expectancy

Aortic Valve EOA Equation:

\[ EOA = \frac{LVOT\ Area \times VTI\ LVOT}{VTI\ AV} \]

Effective Orifice Area (EOA):

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1. What is Aortic Valve EOA?

The Effective Orifice Area (EOA) of the aortic valve is a measurement used to assess the severity of aortic stenosis. It represents the cross-sectional area available for blood flow through the valve during systole.

2. How Does the Calculator Work?

The calculator uses the continuity equation:

\[ EOA = \frac{LVOT\ Area \times VTI\ LVOT}{VTI\ AV} \]

Where:

\( LVOT\ Area \) — Left ventricular outflow tract area (cm²)
\( VTI\ LVOT \) — Velocity time integral of LVOT flow (cm)
\( VTI\ AV \) — Velocity time integral across aortic valve (cm)

Explanation: The equation is based on the principle of conservation of mass (continuity equation), where the stroke volume in the LVOT equals the stroke volume through the aortic valve.

3. Importance of EOA Calculation

Details: EOA is crucial for assessing aortic stenosis severity, guiding treatment decisions, and predicting patient outcomes. It's more reliable than pressure gradients alone as it's less flow-dependent.

4. Using the Calculator

Tips: Enter LVOT area in cm² (usually calculated from LVOT diameter), VTI LVOT and VTI AV in cm (measured by Doppler echocardiography). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are normal EOA values?
A: Normal aortic valve area is 3-4 cm². Values ≤1.0 cm² indicate severe aortic stenosis, though body size should be considered (indexed to body surface area).

Q2: How does EOA relate to life expectancy?
A: Smaller EOA values correlate with worse prognosis. Severe AS (EOA <1.0 cm²) has 50% 2-year mortality without treatment.

Q3: When is this calculation most accurate?
A: Best in native valve assessment with normal LV function. May be less accurate in low-flow states or with irregular rhythms.

Q4: What's the difference between EOA and geometric area?
A: EOA is the functional area (smaller due to flow contraction), while geometric area is the anatomic measurement. EOA better correlates with hemodynamics.

Q5: How often should EOA be measured?
A: In known AS, annual echo is recommended for moderate disease, every 6-12 months for severe asymptomatic AS.