PISA Calculator

Apply the proximal isovelocity surface area (PISA) method to echocardiographic flow-convergence measurements to estimate the effective regurgitant orifice area and regurgitant volume of a leaking heart valve.

Quick Facts

Core formula
EROA = (2πr² × Va) / Vmax
Flow rate through the PISA hemisphere divided by the peak regurgitant jet velocity.
Severity cutoffs
EROA 0.20 & 0.40 cm²
Common guideline bands: mild <0.20, moderate 0.20-0.39, severe ≥0.40 cm² (mirrored by regurgitant volume 30 and 60 mL).
Angle correction
180° = full hemisphere
Use a smaller angle when the flow convergence region is constrained, not hemispheric.

Your Results

Calculated
Effective regurgitant orifice area
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EROA, cm²
Regurgitant volume
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EROA × jet VTI
PISA flow rate
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Instantaneous flow, mL/s
Severity grade
-
Based on EROA & volume

Ready

Enter the PISA radius, aliasing velocity, peak jet velocity, and VTI, then calculate.

About the PISA method

The proximal isovelocity surface area (PISA) method is a Doppler echocardiography technique for quantifying the severity of valve regurgitation, most commonly mitral regurgitation. As blood flows through a regurgitant orifice, it accelerates in a series of roughly hemispheric shells on the upstream side of the leak, each shell representing a surface of equal (isovelocity) flow. Color Doppler aliasing marks the edge of one shell at a known radius and velocity, giving enough information to calculate the flow rate through the orifice, then the effective regurgitant orifice area (EROA) and regurgitant volume.

How the calculation is built

  • Flow rate: the hemisphere's surface area (2πr²) multiplied by the aliasing (Nyquist limit) velocity Va, with an optional angle correction (α/180) when the convergence zone is constrained rather than a full hemisphere.
  • Effective regurgitant orifice area (EROA): the flow rate divided by the peak regurgitant jet velocity (Vmax), measured with continuous-wave Doppler and converted from m/s to cm/s.
  • Regurgitant volume: EROA multiplied by the velocity time integral (VTI) of the regurgitant jet, which represents the total distance blood travels through the orifice each beat.

Putting the result in context

Widely used echocardiography guideline cutoffs grade EROA as mild below 0.20 cm², moderate from 0.20 to 0.39 cm², and severe at 0.40 cm² or above, with regurgitant volume bands of roughly 30 mL and 60 mL marking the same mild/moderate/severe transitions. The two measures usually agree; when they diverge, EROA is generally considered less dependent on loading conditions and is weighted more heavily.

When to consult a professional

This tool performs the standard PISA arithmetic for education and record-keeping. It is not a diagnosis and does not replace a full echocardiographic study. Measurement technique (frame timing, Nyquist shift, Doppler alignment) strongly affects the inputs, so any clinical decision should be made by the interpreting cardiologist or sonographer using the complete study.

Frequently Asked Questions

What does the PISA method measure?
The proximal isovelocity surface area (PISA) method is an echocardiographic technique for quantifying valve regurgitation, most often mitral regurgitation. As blood accelerates toward a regurgitant orifice, it forms a series of hemispheric shells of equal velocity. Measuring the radius of one shell where color Doppler aliases, along with the aliasing velocity, lets you calculate the instantaneous flow rate through the orifice.
How is EROA calculated from PISA measurements?
Flow rate equals 2 times pi times the PISA radius squared, times the aliasing (Nyquist) velocity, times an optional angle correction divided by 180 for a non-hemispheric shell. The effective regurgitant orifice area (EROA) is that flow rate divided by the peak regurgitant jet velocity measured by continuous-wave Doppler, converted to centimeters per second.
How is regurgitant volume graded once EROA is known?
Regurgitant volume equals EROA multiplied by the velocity time integral (VTI) of the regurgitant jet. Under commonly used echocardiography guideline cutoffs, an EROA under 0.20 cm squared or regurgitant volume under 30 mL suggests mild regurgitation, 0.20 to 0.39 cm squared or 30 to 59 mL suggests moderate, and 0.40 cm squared or higher or 60 mL or higher suggests severe regurgitation.

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