Venous Excess Ultrasound (VExUS) Score

Clinical background

Judging whether a critically ill patient is volume overloaded or needs more fluid is a recurring and difficult decision in intensive care and perioperative medicine. Conventional measures such as central venous pressure (CVP), cumulative fluid balance and peripheral oedema all have appreciable limitations: CVP is invasive, sensitive to measurement error and influenced by intrathoracic pressure, mechanical ventilation and valvular disease. Fluid balance does not necessarily reflect systemic venous pressure, and clinical examination has low sensitivity for detecting congestion-related organ injury.

The Venous Excess Ultrasound (VExUS) score was developed to fill this gap by using bedside ultrasound to quantify systemic venous congestion in the splanchnic circulation. The rationale is that venous congestion lowers the arteriovenous pressure gradient across the organs, raises capillary hydrostatic pressure and thereby causes interstitial oedema, which in encapsulated organs such as the kidneys rapidly leads to increased interstitial pressure and reduced organ blood flow. The score is therefore primarily a tool for assessing "fluid tolerance" rather than fluid responsiveness, and for identifying patients in whom further fluid risks worsening organ injury, particularly acute kidney injury.

Calculating the VExUS score

The VExUS score is based on four bedside ultrasound measurements: the IVC diameter together with pulsed-wave Doppler of the hepatic veins, the portal vein and an intrarenal vein. The measurements are made with the patient supine, using a subxiphoid or lateral window for the IVC and hepatic veins, and the posterior axillary line for the intrarenal vein. ECG monitoring is recommended to identify the systolic and diastolic phases of the cardiac cycle and improves reproducibility.

The grading used by the calculator:

$$\text{VExUS grade} = \begin{cases} 0 & \text{if IVC diameter } < 2 \text{ cm} \ 1 & \text{if IVC diameter } \geq 2 \text{ cm and no severely abnormal Doppler pattern} \ 2 & \text{if IVC diameter } \geq 2 \text{ cm and one severely abnormal Doppler pattern} \ 3 & \text{if IVC diameter } \geq 2 \text{ cm and two or more severely abnormal Doppler patterns} \end{cases}$$

The individual Doppler patterns are classified as follows:

The derivation cohort consisted of 145 patients undergoing cardiac surgery with cardiopulmonary bypass at the Montreal Heart Institute between August 2016 and July 2017 [1]. Patients with preoperative critical illness, acute kidney injury or delirium before surgery were excluded, as were patients with cirrhosis, portal vein thrombosis, severe chronic kidney disease (eGFR <15 mL/min/1.73 m²) or a need for dialysis. In total, 706 ultrasound assessments were analysed with daily measurements on postoperative days 0 to 3. The primary outcome was acute kidney injury according to the KDIGO criteria.

Interpretation in practice

The VExUS grade reflects the severity of systemic venous congestion and should be interpreted in the context of the patient's overall haemodynamic picture. Since an IVC diameter <2 cm gives grade 0 irrespective of the Doppler patterns, the IVC acts as a gatekeeper: a narrow, collapsible IVC effectively excludes marked venous congestion.

In the derivation cohort, VExUS grade 3 was independently associated with subsequent acute kidney injury after cardiac surgery, with a hazard ratio of 3.69 (95% CI 1.65 to 8.24, p = 0.001) [1]. After adjustment for preoperative risk and vasopressor/inotropic support the association persisted (HR 2.82, 95% CI 1.21 to 6.55, p = 0.02). At ICU admission, grade 3 had a positive likelihood ratio of 6.37 (95% CI 2.19 to 18.50) for acute kidney injury, which exceeded what was achieved with CVP measurements at various thresholds [1].

Validation and performance

A systematic review and meta-analysis from 2025 included 1,036 patients from nine prospective observational studies of critically ill ICU patients [2]. Overall, a VExUS $\geq$ 2 was associated with acute kidney injury with an odds ratio of 2.63 (95% CI 1.06 to 6.54, p = 0.04), but with considerable heterogeneity (I² = 74%). In the cardiac surgery subgroup the association was stronger and more homogeneous: OR 3.86 (95% CI 2.32 to 6.42, p < 0.0001, I² = 0%). By contrast, there was no significant association between VExUS and mortality (OR 1.25, 95% CI 0.71 to 2.19, p = 0.44) [2].

In the non-surgical subgroup the association disappeared (OR 1.69, 95% CI 0.25 to 11.53, p = 0.59) [2]. A multicentre study from four Chinese ICUs of 108 patients with sepsis confirmed this: a VExUS $\geq$ 2 was not associated with acute kidney injury (OR 1.82, 95% CI 0.62 to 5.31, p = 0.27), nor with mortality or the need for renal replacement therapy [3]. Of 185 patients assessed for inclusion, 42% were excluded, many because an intrarenal venous Doppler signal could not be obtained (n = 26) or because of atrial fibrillation (n = 22) [3].

In patients with acute coronary syndrome, by contrast, VExUS has shown a clear dose–response relationship: the proportion of patients who developed acute kidney injury rose from 10.8% at grade 0 to 100% at grade 3, and a VExUS $\geq$ 1 was independently associated with acute kidney injury on multivariable analysis (OR 6.15, 95% CI 1.26 to 29.94, p = 0.02) in a cohort of 77 patients [4]. A smaller study of 30 patients with cardiorenal syndrome found that improvement in the VExUS grade correlated with resolution of acute kidney injury (p = 0.003) and with fluid balance (p = 0.006), but not with CVP or ventricular function [5].

Inter-rater reliability has been evaluated in a multicentre study with 42 patients and 84 paired examinations, interpreted by four physicians from different specialties [6]. The overall VExUS grade showed good agreement, with a kappa of 0.71 and an ICC of 0.83, whereas the individual components were weaker. The intrarenal venous Doppler had the lowest reliability (kappa 0.32, ICC 0.48). ECG monitoring improved agreement (kappa 0.75 with ECG versus 0.42 without). Feasibility was 75%, limited mainly by difficulty in obtaining technically satisfactory intrarenal Doppler waveforms [6].

Limitations

The VExUS score concerns systemic venous congestion and is derived and largely validated in cardiac surgery patients. Caution is required in extrapolating to other populations, particularly patients with sepsis, in whom an association with acute kidney injury has not been demonstrated [2, 3].

The tool should not be used alone to guide diuretic treatment. VExUS reflects venous congestion irrespective of cause — that is, both volume overload and pressure overload (for example in right heart failure, pulmonary hypertension or tricuspid regurgitation) — and cannot distinguish between these without complementary assessment of cardiac function and volume status [1].

In atrial fibrillation the interpretation of the hepatic vein Doppler may be affected by irregularity of the systolic phase, and patients with atrial fibrillation were excluded from several validation studies [3]. Cirrhosis and portal vein thrombosis may confound assessment of the portal vein Doppler and were excluded from the derivation cohort [1]. The patient must tolerate examination in the supine position, and respiration and mechanical ventilation can affect the IVC diameter and portal vein pulsatility.

The intrarenal venous Doppler is technically demanding and has the lowest reproducibility of the components [6]. Where the acoustic window is poor, this component may be missing, which places additional demands on operator experience and can make the grading less reliable. ECG monitoring is therefore recommended as standard to improve phase identification.

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(1):16. PMID: 32270297
2. Melo RH, Gioli-Pereira L, Melo E, et al. Venous excess ultrasound score association with acute kidney injury in critically ill patients: a systematic review and meta-analysis of observational studies. Ultrasound J. 2025;17(1):16. PMID: 40029471
3. Song J, Chen G, Lai D, et al. Association between the Venous Excess Ultrasound (VExUS) score and acute kidney injury in critically ill patients with sepsis: a multicenter prospective observational study. Ann Intensive Care. 2025;15(1):105. PMID: 40699273
4. Viana-Rojas JA, Argaiz E, Robles-Ledesma M, et al. Venous excess ultrasound score and acute kidney injury in patients with acute coronary syndrome. Eur Heart J Acute Cardiovasc Care. 2023;12(7):413-419. PMID: 37154067
5. Bhardwaj V, Vikneswaran G, Rola P, et al. Combination of Inferior Vena Cava Diameter, Hepatic Venous Flow, and Portal Vein Pulsatility Index: Venous Excess Ultrasound Score (VEXUS Score) in Predicting Acute Kidney Injury in Patients with Cardiorenal Syndrome: A Prospective Cohort Study. Indian J Crit Care Med. 2020;24(9):783-789. PMID: 33132560
6. Longino AA, Martin KC, Leyba KR, et al. Reliability and reproducibility of the venous excess ultrasound (VExUS) score, a multi-site prospective study. Crit Care. 2024;28(1):197. PMID: 38858766