PISA Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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Cardiovascular numbers become useful only when the equation behind them is clear. PISA Calculator turns the specific measurements in this tool into a focused hemodynamic or risk estimate.

What this calculator does

PISA Calculator uses r, Vr, Vmax, α angle, and Velocity time integral (VTI) to calculate PISA-derived regurgitation measurements. It is built around the exact fields displayed in this plugin rather than a generic version of the topic. Where supported, it also shows Mitral valve area (MVA), Volume flow rate (VFR), and Regurgitant volume (RVol) so the primary result is easier to place in context. Cardiovascular formulas are sensitive to measurement technique and clinical context. A mathematically correct output can still be misleading if the input was obtained under a different physiologic condition, with a different assay, or outside the population for which the score was developed.

How to use it

Enter or select r, Vr, Vmax, α angle, and Velocity time integral (VTI). Use the units offered by the calculator and choose the option that matches the actual clinical or timing situation. Check date entries and laboratory units before relying on the output. When the formula combines measurements, use values obtained under the same assessment or physiologic conditions whenever possible.

How the calculation works

The calculator estimates the proximal isovelocity surface area as 2πr², volume flow rate as PISA × aliasing velocity, and EROA as flow rate / peak regurgitant velocity. Regurgitant volume is EROA × VTI. It also reports an angle-adjusted mitral-orifice value using the entered alpha angle as a fraction of 180 degrees.

Example

Using the sample values prefilled in this calculator, the primary result is 0.377 cm² (Effective regurgitant orifice (EROA)), Mitral valve area (MVA) is 0.377 cm², and Volume flow rate (VFR) is 188.5 mL/s. This worked example shows how the plugin’s own default inputs flow through the implemented method; replace them with the correct patient, laboratory, imaging, or personal values before interpreting a result.

How to interpret the result

Read the output as effective regurgitant orifice (eroa) generated by this specific formula or score. The number is most useful when compared with the clinical context and, when appropriate, serial measurements or the current guideline pathway for the condition. A boundary value should not be overinterpreted as a sudden change in physiology.

Limitations and notes

Cardiovascular formulas are sensitive to measurement technique and clinical context. A mathematically correct output can still be misleading if the input was obtained under a different physiologic condition, with a different assay, or outside the population for which the score was developed.