Comparison of subclavian vein to inferior vena cava collapsibility by ultrasound in acute heart failure: A pilot study

Abstract

Background: Management of acute decompensated heart failure (ADHF) requires accurate assessment of relative intravascular volume, which may be technically challenging. Inferior vena cava (IVC) collapsibility with respiration reflects intravascular volume and right atrial pressure (RAP). Subclavian vein (SCV) collapsibility may provide an alternative.

Hypothesis: The purpose of this study was to examine the relationship between SCV collapsibility index (CI) and IVC CI in ADHF.

Methods: This was a prospective study of non-ventilated patients with ADHF who had paired IVC and SCV ultrasound assessments. As SCV CI is highly position-dependent, measurements were performed supine at 30-45°.

Results: Thirty-three patients were included with 36 encounters. The sample size was adequately powered for receiver-operator characteristic (ROC) analysis. SCV CI correlated with IVC CI during relaxed breathing (R = .65, n = 36, p < .001) and forced inhalation (R = .47, n = 36, p = .0036). SCV CI < 22% and >33% corresponded to IVC CI < 20% and >50% suggesting hypervolemia (sensitivity/specificity: 72%) and hypovolemia (sensitivity/specificity: 78%), respectively. Moderate to severe tricuspid regurgitation (TR) compared to less than moderate TR was associated with lower SCV CI (medians: 12.4% vs. 25.3%, p = .022) and IVC CI (medians: 9.6% vs. 35.6%, p = .0012). SCV CI and IVC CI were not significantly different among chronic kidney disease stages.

Conclusion: In non-ventilated ADHF, SCV CI at 30-45° correlates with paired IVC CI, and may provide an alternative to IVC CI for assessment of relative intravascular volume, which may facilitate clinical management. Moderate to severe TR decreases SCV CI and IVC CI and may result in overestimation of relative intravascular volume.

Keywords: acute decompensated heart failure; inferior vena cava ultrasound; subclavian/proximal axillary vein ultrasound; tricuspid regurgitation.

Conflict of interest statement

The authors declare that there is no conflict of interest.

© 2021 The Authors. Clinical Cardiology published by Wiley Periodicals LLC.

Figures

Figure 1

Ultrasound probe positions and ultrasound images of the subclavian vein (SCV) and inferior vena cava (IVC) with respiration. (A) Ultrasound probe positions: distal SCV images were obtained with patients lying supine at an incline of 30–45°. A linear array transducer was placed inferior to the lateral border of the right clavicle, aligned in the deltopectoral groove along the axis of the right arm to obtain a transverse view of the SCV at the junction with the proximal axillary vein. The IVC was imaged via the subcostal window in a longitudinal plane using the phased array transducer. (B) Ultrasound images of the subclavian artery (SCA) and SCV using the linear array transducer with color‐flow Doppler to ensure imaging of the appropriate vessel and to clarify SCV borders. (C) Ultrasound images of the IVC using the phased array transducer. Images are shown during expiration and inspiration. Maximum and minimum SCV and IVC diameters were measured perpendicular to the inner edge of the vessel walls as illustrated by the white lines. IVC diameters were measured 2 cm from the right atrium (RA) or distal to the hepatic vein (HV)

Figure 2

Patient recruitment. IABP, intra‐aortic balloon pump; IVC, inferior vena cava; SCV, subclavian vein; US, ultrasound

Figure 3

Correlations of SCV CI to IVC CI with both relaxed breathing and forced inhalation. Black curved lines represent 95% confidence interval. (A) Correlation of SCV CI to IVC CI with relaxed breathing. R = .65, n = 36, p < .001. (B) Correlation of SCV CI to IVC CI with forced inhalation. R = .47, n = 36, p = .0036. CI, collapsibility index; IVC, inferior vena cava; SCV, subclavian vein

Figure 4

Sensitivity and specificity for SCV CI cutoffs, as predictors for IVC CI 50%, with relaxed breathing. Red circles represent sensitivity and blue squares specificity. Solid curves are sigmoidal fit to data, with values for sensitivity and specificity maxima and minima constrained to 100% and 0%, respectively. SCV CI cutoffs at which sensitivity and specificity are equal and maximal are indicated by the vertical line. (A) Sensitivity and specificity for SCV CI cutoffs, as predictors for whether IVC CI is n = 36, p = .000085). (B) Sensitivity and specificity for SCV CI cutoffs, as predictors for whether IVC CI is >50%, suggesting hypovolemia. SCV CI cutoff of >33% corresponded to equivalent sensitivity/specificity of 78% (AUC of ROC plot = 0.833 ± 0.091 [SE], n = 36, p = .000127). AUC, area under the curve; CI, collapsibility index; IVC, inferior vena cava; ROC, receiver‐operator characteristic; SE, standard error; SCV, subclavian vein

Figure 5

Relationship of first encounter SCV and IVC collapsibility indices and maximum diameters to the severity of tricuspid regurgitation in acute decompensated heart failure. Panels A and B show the relationship of SCV CI and IVC CI to TR in the current study population with acute decompensated heart failure. Higher SCV CI (p = .022 Mann–Whitney) and IVC CI (p = .0012 Mann–Whitney) were seen with less than moderate TR, compared to moderate or greater TR. Panels C and D show the effect of TR on SCVmax and IVCmax. Lower SCVmax (p = .00097 Mann–Whitney) and IVCmax (p = .026 Mann–Whitney) were seen with less than moderate TR, compared to moderate or greater TR in these patients with acute decompensated heart failure. Boxes represent medians and interquartile ranges. CI, collapsibility index; IVC, inferior vena cava; SCV, subclavian vein; TR, tricuspid regurgitation