Mitral Regurgitation (MR) PISA Calculator
Estimate PISA flow rate, effective regurgitant orifice area (EROA), regurgitant volume, and optional regurgitant fraction from echocardiographic measurements.
Educational use only. This calculator supports learning and quick checks. Final MR severity assessment should be integrated with full echocardiographic and clinical data.
What this mitral regurgitation PISA calculator does
The proximal isovelocity surface area (PISA) method helps quantify mitral regurgitation by estimating how much blood leaks backward from the left ventricle into the left atrium during systole. This calculator provides:
- PISA flow rate (mL/s)
- EROA (cm²) — effective regurgitant orifice area
- Regurgitant volume (mL/beat)
- Regurgitant fraction (%) when stroke volume is provided
PISA equations used
The calculation follows the conventional hemispheric PISA model with optional angle correction.
1) Flow rate across the convergence hemisphere
Where r is PISA radius in cm, Va is aliasing velocity in cm/s, and angle is the measured convergence sector angle in degrees.
2) Effective regurgitant orifice area (EROA)
Peak MR velocity is entered in m/s and converted internally to cm/s before division.
3) Regurgitant volume
4) Regurgitant fraction (optional)
How to obtain the inputs correctly
- PISA radius: measure from the regurgitant orifice to the first aliasing contour in mid-systole (zoomed color Doppler).
- Aliasing velocity: use the color baseline shift setting shown during PISA acquisition.
- Peak MR velocity: obtain from continuous-wave Doppler of the MR jet.
- MR VTI: trace CW Doppler MR envelope for full systolic integral.
- Angle correction: use 180° for a full hemisphere; apply narrower angle if constrained convergence is seen.
Simplified interpretation guide
Different guidelines and disease contexts may apply slightly different thresholds. The calculator shows a simplified grade to help with orientation only.
| Context | Common severe threshold (approx.) | Common moderate threshold (approx.) |
|---|---|---|
| Primary MR | EROA ≥ 0.40 cm² or Regurgitant Volume ≥ 60 mL | EROA ≥ 0.20 cm² or Regurgitant Volume ≥ 30 mL |
| Secondary MR | EROA ≥ 0.20 cm² or Regurgitant Volume ≥ 30 mL | EROA ≥ 0.10 cm² or Regurgitant Volume ≥ 20 mL |
Worked example
Suppose a patient has: radius 0.9 cm, Va 40 cm/s, peak MR velocity 5.0 m/s, MR VTI 140 cm, and angle 180°.
- Flow = 2 × π × (0.9²) × 40 ≈ 203.6 mL/s
- Vmax = 5.0 m/s = 500 cm/s
- EROA = 203.6 / 500 ≈ 0.41 cm²
- Regurgitant volume = 0.41 × 140 ≈ 57 mL
This pattern is near severe range in primary MR and should be interpreted with full context (chamber size, pulmonary pressure, symptoms, LV function, and multimodality imaging where needed).
Common pitfalls of PISA measurement
- Assuming a perfect hemisphere when the geometry is not hemispheric.
- Poor frame timing (radius should be measured at representative systolic phase).
- Eccentric, multiple, or dynamic MR jets where single-frame PISA can mislead.
- Suboptimal aliasing velocity setup resulting in unstable radius reading.
- Using isolated quantitative values without integrating qualitative and supportive signs.
Clinical reminder
Mitral regurgitation grading is multiparametric. Use PISA alongside vena contracta, pulmonary vein flow, jet characteristics, ventricular/atrial remodeling, and patient symptoms. If findings disagree, prioritize comprehensive review rather than a single metric.