Table 2 American Society of Echocardiography criteria for MR severity and potential pitfalls [27]
From: Mitral regurgitation in the critically ill: the devil is in the detail
| Â | MR severity | Pitfalls | ||
|---|---|---|---|---|
Mild | Moderate | Severe | ||
MV morphology | None/mild leaflet abnormality | Moderate leaflet abnormality or moderate tenting | Severe valve lesions | -Image quality often limited by mechanical ventilation and ability to optimise patient position -Requires low threshold for TOE if concerns for structural abnormalities |
LV size and function LA size | Usually normal | Normal or mildly dilated | Dilated An LV ejection fraction of \(\le\)60% and LVESD of \(\ge\)40 mm is indicative of LV decompensation [71] | - Poor endocardial definition in the critical care population - Limited access to contrast agents for more accurate measurement - May not be dilated in acute severe MR - The 60/40 rule (LVEF \(\le\) 60% and LVESD > 40 mm) is often used to guide surgical intervention in chronic severe MR |
Colour jet area | Small, central, narrow, brief | Variable | Large central jet (> 50% of LA) or eccentric jet | - Imprecise, particularly in eccentric, wall-hugging jets - Load dependent, jet size very dependent upon systolic BP - Overestimates when MR not holosystolic - Underestimated in acute severe MR due to low MR driving pressure (due to hypotension and very high LAP) |
Flow convergence | Not visible, transient or small | Intermediate in size and duration | Large throughout systole | - Problematic with multiple jets - Eccentric and constrained jets often underestimated - Non-hemispheric shape, particularly in secondary MR - Overestimates when MR not holosystolic |
CWD jet | Faint, partial or parabolic | Dense but partial or parabolic | Holosystolic, dense or triangular | - Qualitative - Angle dependent—central jets appear denser than eccentric jets of higher severity - Density is gain dependent |
Vena contracta (cm) |  < 0.3 | Intermediate |  ≥ 0.7 | - Problematic with multiple jets - Convergence zone needed for accurate measurement - Non-hemispheric shape, particularly in secondary MR |
Pulmonary vein flow | Systolic dominance | Normal or systolic blunting | Systolic flow reversal or minimal systolic flow | - MR may affect flow pattern in individual PVs - Challenging to image with TTE - Systolic blunting not specific for MR—also elevated LAP, AF - All pulmonary veins must be assessed when using TOE, particularly in the presence of eccentric MR jets |
Mitral inflow | A-wave dominant | Variable | E-wave dominant (> 1.2 m/s) | - Not specific to MR - Affected by severe LV dysfunction (low E wave even in severe MR) |
Effective regurgitant orifice area (EROA), 2D proximal isovelocity surface area (PISA) (cm2) |  < 0.20 | 0.2–0.39 |  ≥ 0.40 | - Less accurate with eccentric/multiple jets - Non-hemispheric shape, particularly in secondary MR. 3D PISA may improve accuracy but is seldom performed in the ICU - Significant amplification of small measurement errors through step-wise calculations |
RVol (ml) |  < 30 | 30–59 |  ≥ 60 | - Significant amplification of small measurement errors through step-wise calculations - Not valid if coexistent AR - Volumetric vs PWD methods may give different results |
RF (%) |  < 30 | 30–49 |  ≥ 50 | |