Prospective Evaluation of Venous Excess Ultrasound for Estimation of Venous Congestion

Abstract

Background: Venous excess ultrasound (VExUS) is a novel ultrasound technique previously reported as a noninvasive measure of venous congestion and predictor of cardiorenal acute kidney injury.

Research question: Are there associations between VExUS grade and cardiac pressures measured by right heart catheterization (RHC) and cardiac biomarkers and clinical outcomes in patients undergoing RHC?

Study design and methods: We conducted a prospective cohort study at the Denver Health Medical Center from December 20, 2022, to March 25, 2023. All patients undergoing RHC underwent a blinded VExUS assessment prior to their procedure. Multivariable regressions were conducted to assess relationships between VExUS grade and cardiac pressures, biomarkers, and changes in weight among patients with heart failure, a proxy for diuretic success. Receiver operating characteristic curve and area under the curve (AUC) were derived for VExUS, inferior vena cava (IVC) diameter, and IVC collapsibility index (ICI) to predict right atrial pressure (RAP) > 10 and < 7 mm Hg.

Results: Among 81 patients, 45 of whom were inpatients, after adjusting for age, sex, and Charlson Comorbidity Index, there were significant relationships between VexUS grade of 2 (β = 4.8; 95% CI, 2.6-7.1; P < .01) and 3 (β = 11; 95% CI, 8.9-14; P < .01) and RAP, VExUS grade of 2 (β = 6.8; 95% CI, 0.16-13; P = .045) and 3 (β = 15; 95% CI, 7.3-22; P < .01) and mean pulmonary artery pressure, and VExUS grade of 2 (β = 7.0; 95% CI, 3.9-10; P < .01) and 3 (β = 13; 95% CI, 9.5-17; P < .01) and pulmonary capillary wedge pressure. AUC values for VExUS, IVC diameter, and ICI as predictors of RAP > 10 mm Hg were 0.9 (95% CI, 0.83-0.97), 0.77 (95% CI, 0.68-0.88), and 0.65 (95% CI, 0.52-0.78), respectively. AUC values for VExUS, IVC diameter, and ICI as predictors of RAP < 7 mm Hg were 0.79 (95% CI, 0.70-0.87), 0.74 (95% CI, 0.64-0.84), and 0.62 (95% CI, 0.49-0.76), respectively. In a subset of 23 patients with heart failure undergoing diuresis, there was a significant association between VExUS grade 3 and change in weight between time of RHC and discharge (P = .025).

Interpretation: Although more research is required, VExUS has the potential to increase diagnostic and therapeutic capabilities of physicians at the bedside and increase our understanding of the underappreciated problem of venous congestion.

Keywords: acute kidney injury; diuretic responsiveness; hemodynamics; ultrasound; venous congestion; volume assessment.

Figure 1

Patient enrollment flow diagram. VExUS = venous excess ultrasound.

Figure 2

There were significant linear associations between VExUS grade and intracardiac pressures measured by right heart catheterization. Data presented as violin plots with demarcated quartiles. Width of the column represents the proportion of data located there. VExUS = venous excess ultrasound.

Figure 3

For detection of RAP > 10 mm Hg, the AUC for VExUS was 0.9 (95% CI, 0.83-0.97) compared with 0.77 (95% CI, 0.68-0.87) for IVC diameter and 0.65 (95% CI, 0.52-0.78) for IVC collapsibility. For detection of RAP < 7 mm Hg, the AUC for VExUS was 0.8 (95% CI, 0.71-0.87) compared with 0.77 (95% CI, 0.67-0.89) for IVC diameter. VExUS examination was superior to IVC diameter alone as a means of predicting elevated RAP. AUC = area under the curve; IVC = inferior vena cava; RAP = right atrial pressure; VExUS = venous excess ultrasound.