Venous Congestion Ultrasound: Doppler Signs That Track Organ Fluid Overload

When the heart fails to pump efficiently, pressure backs up through the venous system and into the organs it supplies. That congestion, a sequence of rising heart filling pressures transmitted to the kidneys, liver and other abdominal organs, is now recognized as a major driver of organ dysfunction in heart failure and cardiogenic shock. A narrative review published in Annals of Intensive Care by Bitar, Maadarani and Bitar lays out how bedside ultrasound, from the inferior vena cava to the portal and renal veins, can be used to detect and grade this congestion noninvasively, and critically appraises the evidence behind the emerging Venous Excess Ultrasound, or VExUS, protocol.

The physiological logic is straightforward. Elevated right atrial pressure is transmitted to the abdominal organs and peripheral tissues, and this altered pressure changes the pattern of venous blood flow in the renal, portal, hepatic and inferior vena caval veins in a predictable manner. Those changes can be quantified with pulsed-wave Doppler. The review notes strong epidemiological evidence that, independent of reduced cardiac output and renal blood flow, venous congestion is associated with reduced glomerular filtration rate. In acute heart failure, the work of Mullens and colleagues showed that higher central venous pressure predicted worsening renal function during hospitalization to a greater extent than low cardiac index did, and cardiac index was inversely associated with worsening renal function even though no association was seen with baseline glomerular filtration rate.

The most familiar ultrasound target is the inferior vena cava. In spontaneously breathing patients, the IVC diameter normally decreases during inspiration as negative intrathoracic pressure draws venous return toward the heart. The collapsibility index, calculated as the difference between maximum and minimum diameter divided by the maximum, is used to estimate central venous pressure: a diameter under 2.1 centimeters with more than 50 percent collapse on sniffing generally indicates a CVP of 0 to 5 cmH2O, while a diameter under 2.1 centimeters with less than 50 percent collapse suggests elevated right atrial pressure. But the review is emphatic about the caveats. The collapsibility index has not been validated in patients on positive-pressure mechanical ventilation, elevated intra-abdominal pressure can distort IVC behavior and produce misleading assessments, and conditions such as right ventricular dysfunction, severe tricuspid regurgitation and cardiac tamponade distend the IVC by raising right atrial pressure rather than by reflecting intravascular volume.

Indeed, the review argues that IVC measurements, while able to estimate CVP and its changes, are unreliable indicators of fluid responsiveness. A systematic review by Marik and colleagues found only a weak correlation between CVP and blood volume, and an inability of CVP or its changes to predict the hemodynamic response to a fluid challenge. CVP, the authors conclude, should not be the sole basis for fluid management decisions. This limitation is precisely what pushed researchers toward direct Doppler interrogation of the organs themselves.

The hepatic vein waveform offers the first window. The normal pattern has four components: a retrograde A wave from atrial contraction, antegrade S and D waves, and a transitional V wave. In a healthy person the systolic wave exceeds the diastolic wave. With mild congestion that relationship reverses, and in severe congestive heart failure the S wave inverts above the baseline, a finding called systolic reversal. An electrocardiogram trace is crucial for correct interpretation, since without it the hepatic vein waveform is easily misread. In significant tricuspid regurgitation, however, the inverted S wave simply reflects retrograde venous flow, and portal vein evaluation becomes the preferred sonographic approach in those patients.

The portal vein, normally a low-velocity, largely monophasic vessel flowing at 10 to 30 centimeters per second, becomes increasingly pulsatile as congestion worsens. The portal pulsatility index, the difference between maximum and minimum velocity divided by the maximum velocity times 100 percent, is considered abnormal above 30 percent. With progressive congestion, systolic flow diminishes, then disappears, and in the most severe cases flow reverses direction. An index above 30 percent strongly suggests liver congestion and has been associated with a higher incidence of adverse kidney outcomes, with an odds ratio of 2.2 and a 95 percent confidence interval of 1.3 to 3.6.

Deep in the kidney itself, intra-renal venous Doppler tracks a similar progression. Normal renal venous flow is continuous and monophasic below the baseline; as congestion worsens, the systolic component shrinks and the diastolic component grows, until only a monophasic diastolic wave remains. The renal venous stasis index quantifies this, measuring the proportion of the cardiac cycle in which no renal venous outflow occurs. In patients with right-sided heart failure, particularly after cardiac surgery, a monophasic pattern was independently linked to acute kidney injury, and the discontinuous intra-renal venous flow pattern correlated strongly with renal congestion and poorer prognosis. Among patients admitted with acute heart failure, a congestive intra-renal venous flow pattern was associated with larger increases in serum creatinine, and in patients with pre-existing kidney dysfunction, ongoing congestion corresponded with significantly higher creatinine both at baseline and 90 days after discharge, though a positive response to diuretics mitigated that correlation.

The VExUS score ties these threads together. Developed by Beaubien-Souligny and colleagues in 2020, originally to predict acute kidney injury after cardiac surgery, it combines IVC diameter with hepatic, portal and renal interlobar vein Doppler patterns. Grade 0 means no congestion, grade 1 mild congestion, grade 2 severe congestion in one organ, and grade 3 severe congestion in at least two of the three organ systems, with severe congestion in a vein defined against a dilated IVC of 2 centimeters or more. In cardiac surgery patients, severe VExUS grade showed the strongest correlation with subsequent acute kidney injury among the ultrasonographic combinations studied. The review also reports a small cohort study in which patients with high VExUS grades showed lower diuretic effect during heart failure hospitalization, independent of admission creatinine and prior loop diuretic use, with the renal venous stasis index showing the best prediction of low diuretic efficiency at an area under the curve of 0.76. In patients hospitalized with acute coronary syndrome, AKI rates climbed with each VExUS grade, from 10.8 percent at grade 0 to 100 percent at grade 3, and after multivariable analysis VExUS of grade 1 or higher remained significantly associated with AKI.

Accuracy against invasive standards is still being established. In a prospective study of 81 patients undergoing right heart catheterization, higher VExUS grades effectively identified elevated right atrial pressure and outperformed standard bedside assessment. In a related prospective analysis by Longino and colleagues, VExUS grade correlated significantly with right atrial pressure, predicting a right atrial pressure of 10 mmHg or higher with an area under the curve of 0.99, compared with 0.79 for isolated IVC diameter. Alternative windows exist for difficult patients: femoral venous Doppler showed moderate agreement with VExUS grading in post-cardiac surgery patients, and internal jugular vein measurements, including the jugular vein diameter ratio during Valsalva, can substitute when the IVC is obscured by obesity, bowel distension or surgical wounds, though a systematic review found no evidence of good interrater reliability for the jugular ratio.

The review closes with caution rather than triumph. VExUS requires specialized expertise, and its accuracy depends on sonographer proficiency. Excess body fat, edema and medical devices common in critically ill patients degrade image quality; hepatic fatty infiltration lowers portal pulsatility, cirrhosis alters Doppler indices, and severe tricuspid regurgitation can produce hepatic systolic reversal even when filling pressures are normal or low. Congestion studies assess organ afterload, and results must be read in the context of the whole patient. Larger-scale studies are needed to confirm clinical applicability, and the authors note a current scarcity of rigorously controlled intervention studies showing that VExUS-guided fluid management actually changes outcomes. Ongoing trials, including a substudy of the ANDROMEDA-SHOCK 2 randomized trial in septic shock and a proposed combined VExLUS protocol pairing venous and lung ultrasound, aim to answer whether Doppler-guided decongestion can translate bedside waveforms into better survival and kidney outcomes.

Subject of Research: Ultrasound indicators of organ venous congestion in heart failure

Article Title: Ultrasound indicators of organ venous congestion: a narrative review

Article References: Bitar, Z. I., Maadarani, O. S., & Bitar, M. (2025). Ultrasound indicators of organ venous congestion: a narrative review. Annals of Intensive Care, 15(1), Article 184. https://doi.org/10.1186/s13613-025-01609-x

Image Credits: AI Generated

DOI: 10.1186/s13613-025-01609-x

Keywords: venous congestion, VExUS, point-of-care ultrasound, Doppler, heart failure, acute kidney injury, inferior vena cava, portal vein, hepatic vein, renal Doppler, diuretic response, cardiorenal syndrome