TR severity criteria at a glance
ACC/AHA VHD 2020 TR severity assessment — the parameters that actually grade severity, the supportive findings, and why TR Vmax is not a severity criterion.
An echo report arrives: TR Vmax 3.2 m/s, RA enlargement, 'severe TR by qualitative assessment.' Which findings truly determine severity — and why is TR Vmax not one of them?
Key takeaway
TR severity is assessed by integrating vena contracta width, PISA EROA, regurgitant volume, hepatic vein systolic flow reversal, CW Doppler contour, and right-sided chamber enlargement. TR Vmax reflects pressure gradient, not regurgitant severity.
Key points
- Vena contracta width ≥ 0.7 cm is a primary severe-range signal for TR.
- PISA EROA ≥ 0.40 cm² and regurgitant volume ≥ 45 mL/beat are major quantitative severe-range criteria.
- Hepatic vein systolic reversal, a dense triangular CW Doppler contour, and RA/RV enlargement are strong supportive findings.
- IVC plethora supports elevated RA pressure, but it does not grade TR severity by itself.
- TR Vmax reflects the RV-RA pressure gradient through the simplified Bernoulli equation. It is useful for PASP estimation, not for TR severity grading.
- In severe TR, pressure equalization can lower TR Vmax even when regurgitant burden is maximal.
- TR severity should be judged by integrated assessment — combining quantitative parameters with supportive signs.
When to read this
Read this when reviewing echo reports and trying to separate the findings that grade TR severity from those that mainly reflect pulmonary pressure or RA pressure. Especially useful before applying the TR Severity Tool.
| Parameter | Severe threshold / finding | Severity criterion? |
|---|---|---|
| Vena contracta width | ≥ 0.7 cm | Yes — primary quantitative criterion |
| PISA EROA | ≥ 0.40 cm² | Yes — primary quantitative criterion |
| Regurgitant volume | ≥ 45 mL/beat | Yes — primary quantitative criterion |
| Hepatic vein systolic flow | Systolic reversal present | Yes — strong supportive finding |
| CW Doppler contour | Dense, triangular | Yes — supportive finding |
| RA/RV enlargement | Present | Yes — supportive sign of chronic volume overload |
| IVC plethora | ≥ 21 mm, < 50% collapse | Supportive — reflects elevated RA pressure |
| TR Vmax | Any value | No — reflects RV-RA pressure gradient, not regurgitant severity |
Why integrated assessment matters
No single parameter can reliably grade TR severity on its own. Vena contracta, EROA, and regurgitant volume provide quantitative estimates of regurgitant orifice size and volume. Hepatic vein systolic reversal, CW Doppler contour, and right-sided chamber enlargement support the conclusion that TR is hemodynamically significant.
This is why TR severity should be assessed by integrating multiple findings — especially when individual measurements are borderline, discordant, or technically limited.
TR Vmax: useful for pulmonary pressure, not for TR severity
TR Vmax is the peak velocity of the tricuspid regurgitant jet measured by continuous-wave Doppler. Through the simplified Bernoulli equation, it estimates the RV-RA systolic pressure gradient. With estimated RA pressure, it helps estimate PASP.
This makes TR Vmax clinically useful — but for pulmonary pressure assessment, not TR severity grading. In severe TR, large regurgitant burden raises RA pressure and narrows the RV-RA gradient, so TR Vmax may fall despite severe regurgitation.
The TR Vmax trap
Do not use TR Vmax to reassure yourself that TR is mild. In severe or torrential TR, pressure equalization may produce a deceptively low TR Vmax even when regurgitant burden is maximal. Severity should be judged from vena contracta, EROA, regurgitant volume, hepatic vein systolic reversal, CW Doppler contour, and right-sided chamber remodeling.
TR severity ranges: mild, moderate, and severe
| Parameter | Mild | Moderate | Severe | Key limitation |
|---|---|---|---|---|
| Vena contracta width | < 0.3 cm | 0.3–0.69 cm | ≥ 0.7 cm | Major quantitative parameter; multiple jets and image quality may complicate assessment |
| PISA EROA | < 0.20 cm² | 0.20–0.39 cm² | ≥ 0.40 cm² | Vulnerable to error when PISA assumptions are not met |
| Regurgitant volume | < 30 mL/beat | 30–44 mL/beat | ≥ 45 mL/beat | Influenced by flow conditions and measurement accuracy |
| Hepatic vein systolic flow | Usually systolic dominant | May become blunted | Systolic flow reversal present | Strong supportive finding, but not a standalone grading criterion |
| CW Doppler contour | Faint / parabolic | Intermediate | Dense and triangular | Used as a supportive sign |
| RA/RV enlargement | Usually absent | May be present | Common in chronic severe TR | Supportive sign of chronic remodeling |
| IVC plethora | Usually absent | May be present | Often present | Reflects elevated RA pressure, not severity grading by itself |
| TR Vmax | — | — | — | Used for PASP estimation; not a TR severity criterion |
- Otto CM, et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease. J Am Coll Cardiol. 2021;77(4):e25–e197.
- Zoghbi WA, et al. Recommendations for Noninvasive Evaluation of Native Valvular Regurgitation. J Am Soc Echocardiogr. 2017.
- Lancellotti P, et al. Recommendations for the echocardiographic assessment of native valvular regurgitation. Eur Heart J Cardiovasc Imaging. 2013.
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