The Proximal Isovelocity Surface Area (PISA) calculator is a valuable tool used to assess mitral regurgitation, a condition where blood flows backward into the heart’s atrium due to a malfunctioning mitral valve. The PISA method allows medical professionals to quantify the severity of this condition by measuring two critical parameters: Effective Regurgitant Orifice (ERO) and Regurgitant Volume (RVol). These parameters help determine the extent of mitral regurgitation and guide clinical decision-making.
Formula of PISA Calculator
Effective Regurgitant Orifice (ERO) Formula: ERO (mm²) = π * R²
Where:
- π (pi) is approximately equal to 3.14159.
- R is the radius of the proximal isovelocity surface area (PISA) hemisphere or cone in centimeters.
Regurgitant Volume (RVol) Formula: RVol (mL/beat) = 2π * R² * Vmax * DTI
Where:
- π (pi) is approximately equal to 3.14159.
- R is the radius of the PISA hemisphere or cone in centimeters.
- Vmax is the peak regurgitant velocity (in cm/s).
- DTI is the duration of the regurgitant flow (in seconds).
Quick Reference Table
| Mitral Regurgitation Level | ERO (mm²) | RVol (mL/beat) |
|---|---|---|
| Mild | < 20 | < 30 |
| Mild to Moderate | 20-29 | 30-44 |
| Moderate to Severe | 30-39 | 45-59 |
| Severe | ≥ 40 | ≥ 60 |
Example of PISA Calculator
Let’s illustrate how to use the PISA calculator with a simple example. Suppose a patient’s echocardiogram indicates a mitral regurgitation with a peak regurgitant velocity (Vmax) of 60 cm/s, and the duration of the regurgitant flow (DTI) is 0.5 seconds. To calculate the ERO:
ERO = π * R² ERO = 3.14159 * (60/2)² ERO = 3.14159 * 900 ERO ≈ 2827.43 mm²
In this case, the ERO value exceeds 40 mm², indicating severe mitral regurgitation.
Most Common FAQs
A1: The PISA calculator is primarily used for assessing mitral regurgitation. Other types of regurgitation may require different methodologies and calculations.
A2: Yes, there are various online PISA calculators available, but it’s essential to ensure their accuracy and reliability.
A3: The severity of mitral regurgitation can vary. Mild cases may not require immediate intervention, while severe cases can lead to significant health issues. Consult a healthcare professional for personalized advice.