Use the 2D PISA method to estimate EROA and regurgitant volume for valvular regurgitation in a structured echocardiography worksheet.
The Proximal Isovelocity Surface Area (PISA) method is a quantitative echocardiographic technique used to assess the severity of valvular regurgitation. By measuring the flow convergence zone proximal to a regurgitant orifice, clinicians can calculate the Effective Regurgitant Orifice Area (EROA) and regurgitant volume — key parameters for grading regurgitation severity.
The PISA method is based on the principle of conservation of mass: as blood accelerates toward a regurgitant orifice, it forms concentric hemispheric shells of increasing velocity. At the aliasing boundary visible on color Doppler, the velocity equals the Nyquist limit, and the radius of this hemisphere can be measured to calculate instantaneous flow rate.
This calculator applies the standard PISA formula to compute flow rate, EROA, and regurgitant volume for mitral, aortic, and tricuspid valves. Results are graded according to ASE/ACC guidelines for regurgitation severity. While PISA is most validated for mitral regurgitation with a circular orifice, it is widely used across all valves with appropriate clinical judgment.
The PISA method gives a quantitative way to summarize regurgitation severity that can be reviewed alongside the rest of the echo. This page is most useful when it keeps the multi-step PISA arithmetic transparent rather than leaving the calculation buried in manual notes.
PISA Flow Rate = 2π × r² × Va (mL/s) EROA = PISA Flow Rate ÷ Peak Regurgitant Velocity (cm²) Regurgitant Volume = EROA × Regurgitant VTI (mL) Where r = PISA radius (cm), Va = aliasing velocity (cm/s)
Result: EROA = 0.41 cm², Regurgitant Volume = 61 mL — Severe mitral regurgitation
With PISA radius 0.9 cm and aliasing velocity 40 cm/s, PISA flow = 2π × 0.81 × 40 = 203.6 mL/s. EROA = 203.6 ÷ 500 = 0.41 cm². Regurgitant volume = 0.41 × 150 = 61 mL. Both EROA ≥ 0.40 and RVol ≥ 60 indicate severe MR.
PISA estimates regurgitant flow by measuring the color-Doppler flow-convergence radius at the aliasing boundary, then converting that into flow rate, EROA, and regurgitant volume. It is most widely used for mitral regurgitation, but the same basic logic can be applied to other valves with caution.
The calculation assumes a roughly hemispheric convergence zone and a geometry that is often only approximate in real patients. Eccentric jets, noncircular orifices, tethered leaflets, poor alignment, and beat-to-beat variation can all change the estimate.
Use this worksheet to keep the PISA numbers together and to compare them with the rest of the echocardiographic assessment. Final grading should still be integrative rather than based on PISA alone.
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This page applies the conventional 2D PISA workflow by calculating hemispheric flow rate from the PISA radius and aliasing velocity, then dividing by peak regurgitant velocity to estimate EROA and multiplying by regurgitant VTI to estimate regurgitant volume. It is best read as an echocardiography worksheet that keeps the main calculations together.
PISA has known limitations. Nonhemispheric flow convergence, eccentric jets, noncircular regurgitant orifices, and beat-to-beat variation can all change the estimate, so the output should be interpreted with the rest of the echocardiographic assessment rather than used as a stand-alone severity decision.
PISA stands for Proximal Isovelocity Surface Area. It is a method of quantifying regurgitant flow by measuring the hemispheric convergence zone on color Doppler imaging proximal to a regurgitant orifice.
PISA is well-validated for mitral regurgitation with circular orifices and correlates well with cardiac MRI. Accuracy decreases with eccentric jets, non-circular orifices, or when the convergence zone is not truly hemispheric.
Effective Regurgitant Orifice Area is the cross-sectional area of the regurgitant orifice through which blood flows backward. It is the single best quantitative parameter for grading regurgitation severity.
PISA is recommended as a primary quantitative method for mitral regurgitation. For aortic regurgitation, use pressure half-time and holodiastolic flow reversal. PISA can supplement any valve assessment.
Shift the color Doppler baseline to achieve aliasing at 30–40 cm/s. This creates a well-defined hemispheric convergence zone. Lower velocities produce larger, easier-to-measure hemispheres.
Limitations include: assumption of a hemispheric convergence zone (may be constrained by walls), assumption of a circular orifice (may be crescentic in functional MR), difficulty measuring when the jet is eccentric, and flow entrainment artifacts. Use this as a practical reminder before finalizing the result.