Calculate EROA via PISA or volumetric method for mitral and aortic regurgitation severity grading. Includes regurgitant volume, fraction, and ASE severity tables.
The Effective Regurgitant Orifice Area (EROA) Calculator quantifies valvular regurgitation severity using either the PISA (Proximal Isovelocity Surface Area) method or the volumetric method, following American Society of Echocardiography (ASE) and American College of Cardiology (ACC) guidelines. EROA is a key quantitative parameter for grading mitral and aortic regurgitation as mild, moderate, or severe.
The PISA method uses color Doppler flow convergence proximal to the regurgitant orifice. By measuring the aliasing radius, aliasing velocity, and peak regurgitant velocity, the calculator derives the flow rate through the regurgitant orifice, the EROA, and the regurgitant volume. The volumetric method compares stroke volumes across two valves — the difference represents the regurgitant volume, from which EROA is derived using the regurgitant jet VTI.
Accurate quantification of valvular regurgitation is essential for surgical timing decisions. Current guidelines recommend surgery for severe mitral regurgitation (EROA ≥0.40 cm², regurgitant volume ≥60 mL) and severe aortic regurgitation (EROA ≥0.30 cm², regurgitant volume ≥60 mL) when symptomatic or when ventricular function begins to decline.
Visual assessment of regurgitant jet size on color Doppler is subjective and can overestimate or underestimate severity. Quantitative parameters (EROA, regurgitant volume, regurgitant fraction) provide objective evidence for clinical decision-making, particularly regarding surgical intervention timing. EROA is the most reproducible quantitative parameter across studies. Keep these notes focused on your operational context.
PISA Method: 1. Flow Rate (Q) = 2π × r² × V_aliasing (mL/s) 2. EROA = Q / V_peak (cm²) 3. Regurgitant Volume = EROA × VTI (mL) 4. Regurgitant Fraction = RVol / (SV_forward + RVol) × 100% Volumetric Method: 1. Regurgitant Volume = SV_regurgitant_valve - SV_LVOT (mL) 2. EROA = RVol / VTI_regurgitant_jet (cm²) Severity (Mitral): Mild EROA <0.20, Moderate 0.20–0.39, Severe ≥0.40 cm² Severity (Aortic): Mild EROA <0.10, Moderate 0.10–0.29, Severe ≥0.30 cm²
Result: EROA: 0.50 cm² — Severe Mitral Regurgitation. RVol: 75.4 mL.
Flow Rate = 2π × 1.0² × 40 = 251.3 mL/s. EROA = 251.3 / 500 = 0.50 cm² (≥0.40 = severe). RVol = 0.50 × 150 = 75.4 mL (≥60 mL = severe). This patient has severe MR by both EROA and regurgitant volume criteria. If symptomatic or with declining LV function, surgical referral is indicated.
No single parameter should determine regurgitation severity in isolation. ASE guidelines recommend integrating: structural parameters (LV and LA size, valve morphology), Doppler parameters (jet area/LVOT area ratio, vena contracta width, CW signal density, pulmonary vein flow reversal for MR, descending aortic flow reversal for AR), and quantitative parameters (EROA, regurgitant volume, regurgitant fraction). When parameters are concordant, the diagnosis is straightforward. Discordant findings require clinical judgment and additional testing.
Primary (organic/degenerative) regurgitation results from structural valve abnormalities (prolapse, flail leaflet, endocarditis). Secondary (functional) regurgitation results from ventricular dilation or dysfunction with structurally normal leaflets. The distinction matters for treatment: primary severe MR is treated surgically (repair preferred), while secondary severe MR is treated medically (heart failure therapy, CRT if indicated) with transcatheter repair (MitraClip) for persistent symptoms despite optimal medical therapy.
Real-time 3D echocardiography provides direct planimetry of the vena contracta area (VCA), overcoming the hemispheric assumption of 2D PISA. CMR (cardiac magnetic resonance) provides the most accurate assessment of regurgitant volume by comparing LV stroke volume to aortic flow. 4D flow MRI can directly visualize and quantify regurgitant flow. These modalities are increasingly used when 2D echo findings are borderline or discordant.
EROA (Effective Regurgitant Orifice Area) is the cross-sectional area through which regurgitant blood flows backward through a leaking valve. It represents the "hole" in the valve that is leaking. A larger EROA means more severe regurgitation. It's measured in cm² and is the most reproducible quantitative parameter for grading regurgitation severity.
PISA (Proximal Isovelocity Surface Area) uses the principle that blood accelerating toward a regurgitant orifice forms concentric hemispheric shells of equal velocity (isovelocity surfaces). On color Doppler, the first aliasing contour marks the isovelocity surface where velocity = aliasing velocity. Measuring this radius and the aliasing velocity gives the flow rate, which when divided by peak CW velocity yields the EROA.
For primary (degenerative) severe mitral regurgitation: surgery when symptomatic, LVEF ≤60%, LVESD ≥40mm, new atrial fibrillation, or pulmonary hypertension. For asymptomatic severe MR with preserved LV function, repair (not replacement) is recommended if surgical risk is low and repair likelihood is high (>95%). For severe aortic regurgitation: surgery when symptomatic, LVEF ≤55%, or LVESD >50mm.
PISA assumes: 1) hemispheric flow convergence (violated with eccentric jets, wall impingement, or constrained orifices), 2) circular regurgitant orifice (violated in functional MR with elliptical orifices), 3) flat valve plane (violated with prolapse), 4) single aliasing velocity captures the true flow convergence zone accurately. These limitations can cause over- or underestimation. 3D echocardiography and multi-parameter integration help overcome these issues.
Regurgitant volume (mL) is the absolute amount of blood flowing backward per heartbeat. Regurgitant fraction (%) is the proportion of total stroke volume that flows backward (RVol / [forward SV + RVol]). A patient with high cardiac output may tolerate a large absolute regurgitant volume with a relatively low regurgitant fraction. Both parameters are considered in severity grading per ASE guidelines.
PISA is faster and more commonly used in clinical practice. The volumetric method provides a useful cross-check but requires four separate measurements (two diameters and two VTIs), each subject to error. Ideally, both methods should agree. Discordant results suggest measurement error or technical limitations. 3D echocardiography may provide more accurate EROA measurements than either 2D method.