Published online Apr 27, 2022. doi: 10.4254/wjh.v14.i4.778
Peer-review started: September 30, 2021
First decision: December 4, 2021
Revised: December 30, 2021
Accepted: March 6, 2022
Article in press: March 6, 2022
Published online: April 27, 2022
Processing time: 204 Days and 5 Hours
Congestive hepatopathy, an abnormal state of the liver as a result of congestion, has become a prognostic determinant by insidiously proceeding toward end-stage liver disease without effective biomarkers in patients with congestive heart diseases as survival has been prolonged owing to surgical and medical improvements. Although liver stiffness is generally a useful surrogate marker for liver fibrosis, which is a universal prognosticator in any type of chronic liver disease, regular measurements of shear wave elastography cannot qualify liver fibrosis in cases of congestion because congestion makes the liver stiff without fibrosis. A noninvasive biomarker is demanded for the managements of patients with congestive heart diseases.
When it is difficult to clearly visualize some area of the liver in ultrasound study, we ask patients to change body postures from supine to such as left decubitus position. At that time, we realized that shear wave elastography values substantially changed in some case. We hypothesized that the effects of congestion and fibrosis on liver stiffness may be dissociated by measuring shear wave elastography in different body positions.
To establish a strategy that enables the evaluation of fibrous accumulation in the liver with respect to architectural rigidity under congestive circumstances by measuring shear wave elastography.
Two-dimensional shear wave elastography was measured in the supine and left decubitus positions in 298 consecutive cases as they were subjected to an ultrasound study for various liver diseases. To clarify the relationship between liver stiffness and interstitial tissue pressure, virtual touch quantification of point shear wave elastography was measured before and after cardiac surgery in a different cohort consisting of 41 cases. Regions of interest were placed at twelve sites, and the median and robust coefficient of variation were calculated. The liver stiffness values and clinicopathological data such as cardiothoracic ratio and the Fibrosis-4 Index were statistically analyzed.
The inferior vena cava diameter was significantly reduced in left decubitus (Ld) position in subjects with higher 2-dimensional shear wave elastography (2dSWE) value in Ld (LdSWE) than the 2dSWE value (SpSWE) in supine (Sp) (P = 0.007) but not in those with lower LdSWE values (P = 0.32). Among 81 patients, in whom SpSWE was increased or decreased in Ld beyond the magnitude of robust coefficient of variation, all 37 with normal SpSWE had a higher LdSWE than SpSWE (Normal-to-Hard), whereas in 44 residual subjects with abnormal SpSWE, LdSWE was higher in 27 subjects (Hard-to-Hard) and lower in 17 subjects (Hard-to-Soft) than SpSWE. SpSWE was significantly correlated with the difference between 2dSWE values in Sp and Ld (∆2dSWE) only in Hard-to-Soft (P < 0.0001). ∆2dSWE was larger in each lobe than in the entire liver. When Hard-to-Hard and Hard-to-Soft values were examined for each lobe, fibrosis-4 or platelet counts were significantly higher or lower only for Hard-to-Soft vs Normal-to-Hard cases.
With the help of gravity during body postural changes, the impacts on architectural rigidity and interstitial tissue pressure are dissociated when measuring liver stiffness. Because a rigid liver is resistant to structural deformation, stiff-liver softening in left decubitus position suggests fiber accumulation of the liver. In this report, a simple strategy of liver stiffness measurement is proposed to identify clues to liver fibrosis even under congestive circumstances.
Because there is no standardized indicator for liver fibrosis in congestive hepatopathy, a longitudinal observation would be only the way to validate the efficacy of liver stiffness measurements in supine and left decubitus postures as a decision guidance strategy with respect to the burden of liver diseases in a cohort of congestive heart diseases. Furthermore, synergistic studies that measure shear wave elastography and quantify structural deformation of the liver in different body positions will help understand the physiological components and mechanisms defining liver stiffen.