EROA is the size of the hole through which blood leaks back. It is the most robust single measure of regurgitation severity because it depends less on blood pressure and heart rate than jet size.
How to use the EROA Calculator
- Method
- PISA radius
- Aliasing velocity
- Peak MR velocity
- Mitral annulus diameter
- Mitral inflow VTI
- LVOT diameter
- LVOT VTI
- MR VTI
Results update as you type, and every field accepts the units shown in its menu.
How it works
Choose the method. For volumetric, enter mitral annulus diameter and VTI, LVOT diameter and VTI, and MR VTI.
Inputs explained
| Field | What to enter |
|---|---|
| Method | Choose one: PISA, Volumetric |
| PISA radius | Units: cm, mm |
| Aliasing velocity | In cm/s |
| Peak MR velocity | In cm/s |
| Mitral annulus diameter | Units: cm, mm |
| Mitral inflow VTI | In cm |
| LVOT diameter | Units: cm, mm |
| LVOT VTI | In cm |
| MR VTI | In cm |
What each result means
- Mitral stroke volume = pi×([Mitral annulus diameter]÷2)^2×[Mitral inflow VTI]
- LVOT stroke volume = pi×([LVOT diameter]÷2)^2×[LVOT VTI]
- Regurgitant volume = [EROA]×[MR VTI]
- Regurgitant fraction = [Regurgitant volume]÷([LVOT stroke volume] + [Regurgitant volume])×100
Example values
How the main result changes when PISA radius changes and everything else stays at the example values above:
| PISA radius (cm) | EROA (cm²) |
|---|---|
| 0.45 | 0.1 |
| 0.675 | 0.23 |
| 0.9 | 0.41 |
| 1.13 | 0.64 |
| 1.35 | 0.92 |
| 1.8 | 1.63 |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
PISA: EROA = 2πr² × Va ÷ peak MR velocity
Volumetric: RVol = SV(mitral) − SV(LVOT); EROA = RVol ÷ MR VTI
Regurgitant fraction = RVol ÷ SV(mitral) × 100
Worked example
Inputs — Method: PISA; PISA radius: 0.9 cm; Aliasing velocity: 40 cm/s; Peak MR velocity: 500 cm/s; MR VTI: 150 cm.
Results — Mitral stroke volume = 121 mL; LVOT stroke volume = 62 mL; EROA = 0.41 cm²; Regurgitant volume = 61 mL; Regurgitant fraction = 49 %.
Key terms
- EROA
- Effective regurgitant orifice area.
- RVol
- Regurgitant volume.
Frequently asked questions
What is a severe EROA?
0.40 cm² or more for primary mitral regurgitation.
What regurgitant fraction is severe?
50% or more.
Which method is better?
PISA is quicker; the volumetric method helps when PISA is unreliable, such as with eccentric jets.