EROA Mitral Regurgitation Calculator - PISA & VTI Plan

An EROA mitral regurgitation calculator turns four echo measurements (the PISA shell radius, the colour Doppler aliasing velocity, the peak velocity of the MR jet, and the VTI of that jet) into a single effective regurgitant orifice area in cm^2, the volume flow rate in mL per second, the regurgitant volume in mL, and the ACC/AHA 2014 grade label (A at risk, B progressive, C asymptomatic severe, D symptomatic severe).

• • Echo workflow: drop in the PISA radius, aliasing velocity, Vmax, and VTI from a transthoracic echo and read the EROA, Rvol, VFR, and grade on the same screen.
• • MR severity review: use the EROA and Rvol pair to confirm the guideline thresholds and to flag severe primary MR (EROA at or above 0.4 cm^2, Rvol at or above 60 mL).
• • Symptom-aware staging: flip the symptoms toggle to upgrade the grade from C to D when decreased exercise tolerance or exertional dyspnoea is present.
• • Teaching and review: use the formula box and the VFR step to teach the PISA derivation and the continuous-wave jet connection.

EROA stands for effective regurgitant orifice area, and Rvol is the volume of blood that flows back through that opening with each heartbeat. Together they convert a colour Doppler image and a continuous-wave Doppler tracing into a single severity band, which is why an EROA mitral regurgitation calculator is the standard way to read the result.

The EROA mitral regurgitation calculator is a planning tool, not a clinical decision. The final call sits with the cardiology or cardiothoracic surgery team.

Mitral regurgitation shares the echocardiography workflow with aortic stenosis, and the Aortic Valve Area Calculator covers the continuity equation, Gorlin, and Hakki formulas that use the same Doppler and BSA inputs.

The EROA mitral regurgitation calculator works in three short steps. It reads the four PISA inputs, applies the PISA VFR formula and divides by the peak velocity of the MR jet to get the EROA in cm^2, and multiplies the EROA by the VTI to get the Rvol in mL. The grade label uses the ACC/AHA 2014 thresholds, with the symptoms toggle upgrading C to D.

The PISA VFR in mL per second is 2 pi r squared Va. The EROA is the VFR divided by Vmax, the Rvol is the EROA times the VTI, and the unit math reduces cleanly to cm^2 and mL.

According to ACC/AHA 2014 VHD Guideline (Nishimura et al., Circulation 2014), severe primary mitral regurgitation is an EROA at or above 0.4 cm^2 or an Rvol at or above 60 mL, with the grade C label applied when the patient is asymptomatic and grade D when symptoms are present.

According to Grayburn, Weissman, Zamorano; Circulation 2012, the EROA in cm^2 is the PISA VFR in mL per second divided by the peak velocity of the mitral regurgitation jet, and the Rvol in mL is the EROA times the VTI of the jet.

The PISA measurement is taken at mid-systole, and confirming a stable heart rate through the ECG Heart Rate Calculator helps place the shell radius inside a single beat.

Four concepts drive the result. Naming them keeps the EROA and Rvol pair from being read as a single lab number, which they are not.

The regurgitant volume in the EROA workflow is the single-beat volume that returns to the left atrium instead of reaching the kidneys, and the GFR Calculator picks up that drop in perfusion as a falling eGFR.

The form works from a small set of echo measurements. Each input should be set to a value that reflects the measurement as it was taken, not an idealised version.

1. 1 Set the aliasing velocity and freeze the image: set the colour Doppler aliasing velocity, freeze at mid-systole, and locate the PISA hemisphere on the atrial side of the mitral valve.
2. 2 Measure the PISA radius: measure the PISA shell radius in cm from the centre of the regurgitant orifice to the aliasing boundary at mid-systole.
3. 3 Trace the continuous-wave jet: read the peak velocity Vmax in cm per second and the VTI in cm from the same continuous-wave Doppler trace.
4. 4 Enter the inputs: type the aliasing velocity, Vmax, and VTI into the form.
5. 5 Set the symptoms toggle: leave on Asymptomatic or switch to Symptomatic to upgrade C to D when severe MR criteria are met.
6. 6 Read the result panel: look at the VFR, the EROA, the Rvol, the severity labels, and the ACC/AHA 2014 grade together.

A reader with a PISA radius of 0.7 cm, an aliasing velocity of 30 cm/s, a Vmax of 480 cm/s, and a VTI of 110 cm can enter those four numbers, leave the symptoms toggle on Asymptomatic, and read the VFR, EROA, Rvol, and grade together.

Calculating the EROA and Rvol from a small set of echo measurements has several practical benefits over running the PISA math by hand.

• • PISA arithmetic done in one form: the four PISA inputs feed the VFR, EROA, and Rvol steps in a single panel.
• • EROA and Rvol side by side: the result panel shows the EROA in cm^2 and the Rvol in mL together, with a separate severity label for each.
• • ACC/AHA 2014 grade built in: the grade label follows the 2014 AHA/ACC primary MR staging (Grade A at risk, B progressive, C asymptomatic severe, D symptomatic severe).
• • Symptoms toggle for staging: the symptoms toggle lets the same form return Grade C or Grade D without re-entering the echo numbers.
• • Visible VFR step for audit: the VFR intermediate result is shown on the result panel, so a reader can audit the PISA arithmetic before the EROA division.

The same form works for self-tracking (a patient who wants to follow the EROA between echo visits) and for shared tracking (a clinician who wants a quick reproducibility check on a reported result). Bring the EROA and Rvol pair to the next cardiology visit, especially when one of them lands in the severe band.

Severe MR changes how the left ventricle fills, and pairing the EROA result with a current systolic and diastolic reading through the Blood Pressure Calculator gives the cardiology review the same cardiovascular risk context as the echo report.

The EROA mitral regurgitation calculator is a planning tool. Several factors shape the result. The most important ones sit inside the entered form, and a small set of caveats belong outside the form.

• • The PISA method assumes a hemispherical shell of accelerating blood on the atrial side of the valve. In some patients the shell is not a true hemisphere, and 3D colour Doppler or planimetry of the vena contracta can give a more accurate EROA.
• • The result is a planning estimate, not a diagnosis. The final clinical decision sits with the cardiology or cardiothoracic surgery team and should consider symptoms, left-ventricular function, pulmonary pressures, atrial size, and exercise testing in addition to the EROA and Rvol pair.

The 2014 AHA/ACC valvular heart disease guideline pairs the EROA and Rvol with the regurgitant fraction and the vena contracta in the severe range, so a value above the severe band is reassuring only when the regurgitant fraction and the vena contracta agree.

According to American Society of Echocardiography Valve Disease Resource Library, the effective regurgitant orifice area is calculated from the PISA radius and aliasing velocity divided by the peak velocity of the regurgitant jet.

Ischaemic MR is one of the chronic causes of secondary MR, and reviewing low-density lipoprotein with the LDL Calculator is a sensible follow-up step because the EROA result only quantifies the regurgitation, not the coronary risk behind it.