TR severity criteria at a glance
ACC/AHA VHD 2020 TR severity assessment — the parameters that grade severity, the supportive signs, and why TR Vmax is not a severity criterion.
An echo report arrives: TR Vmax 3.2 m/s, RA enlarged, 'severe TR by qualitative assessment.' Which parameters actually determine severity — and why isn't TR Vmax one of them?
Key takeaway
TR severity is graded by vena contracta width, PISA EROA, regurgitant volume, hepatic vein systolic flow reversal, CW Doppler contour, and right-sided chamber remodeling. TR Vmax reflects pressure gradient — not severity.
Key points
- Vena contracta ≥ 0.7 cm is a primary severe-range signal for TR.
- PISA EROA ≥ 0.40 cm² and regurgitant volume ≥ 45 mL/beat are quantitative severe-range criteria.
- Hepatic vein systolic reversal, dense triangular CW Doppler, and RA/RV enlargement are strong supportive signs — not standalone criteria.
- TR Vmax reflects the RV-RA pressure gradient via the simplified Bernoulli equation. It is used to estimate PASP — not to grade TR severity.
- In severe TR, pressure equalization can lower TR Vmax even as regurgitant burden is maximal.
- Integrated assessment — combining quantitative parameters with supportive signs — is the standard approach.
When to read this
Read this when reviewing echo reports for TR and trying to identify which parameters reflect severity versus pulmonary pressure. 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 sign |
| CW Doppler contour | Dense, triangular | Yes — supportive sign |
| RA/RV enlargement | Present (chronic volume overload) | Yes — supportive sign of chronicity |
| IVC plethora | ≥ 21 mm, < 50% collapse | Supportive — elevated RA pressure context |
| TR Vmax | Any value | No — reflects RV-RA pressure gradient, not regurgitant volume |
Why integrated assessment matters
No single parameter reliably grades 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 remodeling confirm that the TR burden is hemodynamically significant.
The integrated approach combines multiple parameters — especially when individual measurements are technically limited, discordant, or at the borderline of the severe threshold.
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. Adding estimated RA pressure gives an estimated PASP.
This makes TR Vmax clinically useful — but for pulmonary pressure assessment, not for TR severity grading. In severe TR, a large regurgitant volume loads the RA and raises RA pressure. As RA pressure approaches RV systolic pressure, the RV-RA gradient narrows and TR Vmax falls. A low TR Vmax in a patient with RA/RV dilation, IVC plethora, and hepatic vein reversal may reflect pressure equalization — not mild TR.
The TR Vmax trap
Do not use TR Vmax to reassure about TR severity. In severe or torrential TR, pressure equalization can produce a TR Vmax that appears low — while the actual regurgitant burden is maximal. Assess severity with vena contracta, EROA, regurgitant volume, and supportive signs.
- 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.