The PISA calculator allows you to efficiently calculate the mitral regurgitation level, mitral valve regurgitant volume, and the effective regurgitant orifice area (EROA). ❣️

The PISA MR tool can also serve as a mitral stenosis, volume flow rate and mitral valve area (MVA) calculator.

Read on to find out more about the PISA method, calculations, and the calculator itself.

How to measure PISA on echo?

PISA is an abbreviation for proximal isovelocity surface area. It's a method used for the echocardiographic assessment of valve regurgitation, mitral valve area, and mitral stenosis level. With the PISA method, we’re able to calculate the area of a mitral circular orifice's hemisphere.

The well known Venturi effect (the effect of "the open doors") describes the acceleration of fluid/air when it crosses a narrowed orifice. The same rule applies for the mitral valve (MV). The acceleration of the blood flow is considered directly proportional to the speed it achieves when crossing the MV. To put it simpler – the narrower the orifice, the higher the speed.

Venturi

Unfortunately, life likes to get complicated. A less known fact is that in reality, fluids increase their speed before approaching the orifice. That’s why we can’t use the simple circle plane to assess it’s area, and we’re forced to use the shape of a hemisphere.

Doppler echocardiography and the PISA echo calculators are essential for the described task.

💡Doppler is a mode of the ultrasound machine that can visualise the movement and the velocity of the fluids within the human body.

When measuring PISA, pay attention to measure it at its maximum point along a single plane; we’re looking for a line that’s directly within your probe’s beam.

  • Sometimes, the task to visualize PISA is straightforward – it’s usually a case for patients with severe mitral stenosis. Remember to maximize your scale!
  • Save at least a few planes – look through all of them, searching for the greatest PISA visible.
  • Measure the PISA radius from the vena contracta to the furthest edge of the PISA.
💡Vena contracta is the point of the orifice when the fluid's speed is the highest, and the diameter of the stream is the smallest possible.

Use the obtained radius to perform further calculations, such as PISA mitral regurgitation or MVA.

Are you eager to find out more? Try our other heart calculators:

How to use the PISA calculator?

Feeling confused? Our simple guide will explain the shortest possible way to achieve your results.

Let's say that our patient is a 56-year-old Caucasian male suffering from the symptoms of mitral stenosis. We want to confirm that diagnosis using the Doppler ultrasound.

We obtained the following values:

  • Peak mitral velocity (Vmax) - 30 cm/s;
  • Radial distance (r) - 0.5 cm;
  • Aliasing velocity at r (Vr) - 10 cm/s;
  • α angle - 25 degrees; and
  • Velocity time integral (VTI) - 10 cm.

Which of these values are necessary for our calculations?

  1. We'd like to calculate the mitral valve area (MVA)

    We need to input the Vmax, r, Vr, and α angle.

    Our tool will generate a predicted level of stenosis based on a calculated the MVA value; in our patient's case, the MVA indicates severe stenosis.

  2. We'd like to know the regurgitation level

    We'll need r, Vr, Vmax to obtain the effective regurgitant orifice (EFO). If you also add the VTI, you'll be able to discover the regurgitant volume (RVol) as well. Compare these two results.

    In our patient's case, the EFO indicates severe and RVol of mild mitral regurgitation.

  3. We'd like to know the PISA itself

    You'll only need to know your patient's r. In this case, the value of PISA is equal to 1.6.

How to assess the PISA MR calculator's results?

Our tool not only calculates everything that you need to know - but it also evaluates your results in a blink of an eye! However, if you'd like to know the rules we followed, take a look at one of the tables below:

  1. Mitral regurgitation echo criteria:
ERO (mm²)RVol (mL/beat)
Mild<20<30
Mild-Moderate20-2930-44
Moderate-Severe30-3945-59
Severe≥40≥60
  1. Mitral valve area criteria:
MVA (cm²)
Normal4.0-5.0
Mild>1.5
Moderate1.0-1.5
Severe<1.0

How to calculate mitral valve with PISA?

PISA calculations are not as tricky as they seem - here's the section in which you can follow the formulas we used for assessing both the mitral valve (MV) regurgitation and area.

  1. Our mitral regurgitation echo calculator uses the following equations:

    PISA = 2πr²,

    where:

    • PISA stands for the proximal isovelocity surface area, given in cm²; and
    • r is the radial distance from the orifice (PISA radius), given in cm.

    VFR = 2πr² * Vr,

    where:

    • VFR is for the volume flow rate, given in ml/s;
    • Vr stands for the aliasing velocity at the radial distance r (in cm/s); and
    • r means the radial distance from the orifice, given in cm.

    ERO = (VFR) / Vmax,

    where:

    • ERO (EROA) is the effective regurgitant orifice area, given in cm²;
    • VFR stands for the volume flow rate, given in ml/s; and
    • Vmax is the peak mitral stenosis velocity measured by the continuous-flow Doppler, given in cm/s.

    RVol = ERO * VTI,

    where:

    • RVol is the regurgitant volume, given in mL/beat (1 mL = 1 cm³);
    • ERO is the effective regurgitant orifice, given in cm²; and
    • VTI means the velocity time integral of the mitral regurgitant jet, given in cm.
  2. We used the following equations for the mitral stenosis assessment:

    MVA = ( 2πr² * Vr * (α angle/180) ) / Vmax,

    where:

    • MVA is the mitral valve area, given in cm²;
    • Vr stands for the aliasing velocity at the radial distance r (in cm/s);
    • α angle means the angle between two mitral leaflets on the atrial side, given in degrees (°); and
    • Vmax is the peak mitral stenosis velocity measured by the continuous-flow Doppler, given in cm/s.

    VFR = 2πr² * Vr,

    where:

    • VFR is for the volume flow rate, given in ml/s;
    • Vr stands for the aliasing velocity at the radial distance r (in cm/s); and
    • r means the radial distance from the orifice, given in cm.
Łucja Zaborowska, PhD candidate
Vmax
cm/s
r
cm
Vr
cm/s
α angle
deg
Velocity time integral (VTI)
cm
Results
Mitral valve area (MVA)
cm²
Volume flow rate (VFR)
ml
/s
Effective regurgitant orifice (ERO, EROA)
mm²
Regurgitant volume (RVol)
ml
/beat
PISA
cm²
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