VExUS Grading Guide

Sequence

1. Measure the maximal IVC diameter. Under 2 cm is grade 0 and the exam stops there. 2 cm or more moves on to Doppler.^1,2
2. Obtain pulsed wave Doppler of a hepatic vein, the main portal vein and an intrarenal interlobar vein, with an ECG tracing on screen.¹
3. Grade each vein, then count how many are severely abnormal.^1,2

IVC measurement

• View: subxiphoid long axis of the intrahepatic IVC. If that window is poor, move laterally over the liver to a right-sided view.¹ Confirm in short axis as well, since an off-axis long-axis cut can underestimate the diameter (cylinder effect).³
• Location: the derivation study measured 2 cm from the hepatic vein junction.¹ The ASE right heart guideline uses 1 to 2 cm caudal to that junction.⁵ Sites vary between later studies.^2,6
• Measure the maximal diameter over the respiratory cycle,¹ perpendicular to the long axis of the vessel.⁵ In a spontaneously breathing patient that is usually end-expiration.⁵
• Cutoff: under 2 cm is grade 0. 2 cm or more counts as dilated, so 2.0 cm exactly counts.^1,2
• Collapsibility is not part of VExUS. The derivation study used maximal diameter only.¹ A 2.3 cm IVC that collapses 50% is still dilated for VExUS grading. Collapsibility belongs to the separate ASE estimate of right atrial pressure (over 2.1 cm with under 50% collapse suggests high RAP).⁵
• An IVC under 2 cm is grade 0 even if the Doppler patterns look abnormal. The IVC works as a gate.²

Venous patterns

Wave glossary

How to read the display: flow toward the probe plots above the baseline, flow away plots below. In the subcostal view the hepatic veins drain away from the probe toward the heart, so normal hepatic flow sits below the baseline.⁴

Hepatic vein

The hepatic veins empty straight into the right atrium, so their waveform follows right atrial filling and pressure through the cardiac cycle.⁴

AAtrial contraction

After the P wave, the right atrium contracts. Some blood is pushed backward toward the liver, giving a small retrograde wave above the baseline. Loses its organized shape in atrial fibrillation.⁴

SSystolic wave

After the QRS, the right ventricle contracts and pulls the tricuspid annulus toward the apex. Right atrial pressure drops and blood is drawn toward the heart, giving a wave below the baseline. Normally the dominant wave. It shrinks as right atrial pressure rises or with tricuspid regurgitation, and reverses above the baseline when regurgitant flow or congestion is severe.^1,4

VVentricular filling of the atrium

Near the end of the T wave, the tricuspid annulus returns to its resting position. Flow out of the liver slows to a brief transition point near or just above the baseline.⁴

DDiastolic wave

After the T wave, the tricuspid valve opens and the right atrium empties into the right ventricle. Blood flows passively from the liver into the heart, below the baseline. Normally smaller than S; becomes the dominant wave as congestion develops.^2,4

Portal vein

VmaxPeak velocity

The highest portal velocity in the cardiac cycle. Portal flow is hepatopetal (toward the liver), so it plots above the baseline.³

VminTrough velocity

The lowest velocity in the cycle. Normal portal flow is continuous or only minimally pulsatile, so Vmin sits close to Vmax. With systemic venous congestion, Vmin falls further below Vmax.³ If it drops below zero, flow is reversing.

PFPulsatility fraction

(Vmax − Vmin) / Vmax × 100. The number VExUS grades for the portal vein.³

Intrarenal vein

Interlobar veins also drain toward the right atrium, so their phases line up with the hepatic S and D waves. As venous pressure rises, flow stops during part of the cycle.²

SSystolic phase

Venous flow during ventricular systole, timed with the hepatic S wave. Lost first as congestion worsens.^1,2

DDiastolic phase

Venous flow during diastole, timed with the hepatic D wave. The last phase left in severe congestion (monophasic, D only).^1,2

ArtRenal artery

The interlobar artery sits next to the vein and plots above the baseline. It shows up in the same sample gate but is not graded in VExUS.

Other terms

ECGGating

The ECG strip under each trace times the waves. Without it, S and D are easy to swap.¹

↑↓Antegrade, retrograde

Antegrade is normal-direction flow (toward the heart in the hepatic and renal veins, toward the liver in the portal vein). Retrograde is flow in the opposite direction.

WFWall filter

Removes very low velocities near the baseline, which is why the trace shows a thin black gap right at zero.

Portal pulsatility fraction

PF = (Vmax − Vmin) / Vmax × 100

³

A PF over 100% means flow reverses below the baseline during part of the cycle.

Overall grade

Reading pitfalls

• Use a simultaneous ECG to tell S from D. S follows the QRS; D follows the T wave.¹
• Tricuspid regurgitation lowers the S wave and, when severe, reverses it, independent of volume status.^1,4
• Atrial fibrillation removes the organized A wave and makes the hepatic waveform irregular.⁴ Some validation studies excluded chronic AF.⁶
• Cirrhosis can make the portal vein non-pulsatile even with severe congestion,³ and can flatten the hepatic vein waveform.⁴ Thin, healthy people can show increased portal pulsatility.³ The derivation study excluded cirrhosis and portal vein thrombosis.¹
• Chronic kidney disease and obstructive uropathy can alter intrarenal venous flow.³ The derivation study excluded severe CKD.¹
• Judge several beats, not one. Respiration changes the amplitude from beat to beat.
• VExUS was derived in patients after cardiac surgery, where grade 3 predicted acute kidney injury.¹ A multicenter general ICU cohort found no significant association between VExUS and AKI or 28-day mortality,⁶ so use outside cardiac surgery rests on weaker evidence.

References

1. Beaubien-Souligny W, Rola P, Haycock K, et al. Quantifying systemic congestion with point-of-care ultrasound: development of the venous excess ultrasound grading system. Ultrasound J. 2020;12:16. Link
2. Longino A, Martin K, Leyba K, et al. Reliability and reproducibility of the venous excess ultrasound (VExUS) score, a multi-site prospective study: validating a novel ultrasound technique for comprehensive assessment of venous congestion. Crit Care. 2024;28:197. Link
3. Argaiz ER, Miralles F, Koratala A. POCUS spotlight: venous excess ultrasound score (VExUS). ASRA Pain Medicine News. August 2023. Link
4. Scheinfeld MH, Bilali A, Koenigsberg M. Understanding the spectral Doppler waveform of the hepatic veins in health and disease. RadioGraphics. 2009;29(7). Link
5. Rudski LG, Lai WW, Afilalo J, et al. Guidelines for the echocardiographic assessment of the right heart in adults. J Am Soc Echocardiogr. 2010;23(7):685-713. As summarized by OpenAnesthesia. Link
6. Andrei S, et al. Prevalence of systemic venous congestion assessed by VExUS and association with acute kidney injury in a general ICU cohort: a prospective multicentric study. Crit Care. 2023. Link