Review for 10.1186/s12876-025-03816-z (2025)

Title: Correlation and Consistency Analysis between Various Indirect Portal Pressure Gradients
and Actual Portal Pressure Gradient
Version: 2 Date: 28 Jan 2025
Reviewer's report:
The retrospective study by Chen et al. addresses pressure measurements in hepatic veins of
patients with decompensated cirrhosis. It compares hepatic venous pressure gradients (HVPG)
with the gradient measured in the portal vein and the vena cava inferior in 120 patients
receiving a TIPS. Authors concluded that f-HVPG and I-HVPG demonstrated high correlation
and consistency. However, compared with PPG, both gradients (f-HVPG and I-HVPG) show
significantly different absolute values and a limited correlation, a fact which is not sufficiently
considered in the conclusions. According to their results, authors should question the use of hv-
measurements in general and not just repeat the previous recommendation to prefer measurement
in the IVC in cases with a FHVP-IVCP of > 2 mmHg.
Comments
General: Line and page numbers are missing which makes addressing of comments difficult.
1. Abstract, results: value not velue.
2. Abstract conclusions:  The conclusion to use I-HVPG when F-HVPG minus I-HVPG >2
mmHg is already standard knowledge and not new. Instead, your results question the use of
F-HVPG and suggest that l-HVPG should be used only because the I-HVPG shows a better
correlation with the gold standard (PPG) in all patients as well as in patients with a FHVP-
IVCP >2 mmHg. Therefore, there is neither a need nor does it make sense to perform pressure
measurement in the free hepatic vein.
3. Introduction: A critical validation of the WHVP is missing. In many patients, WHVP
measurement is compromised by collaterals between hepatic veins (see comment 15, Lv et al).
4. Second para: FHVP not FVHP
5. Methods: first para: ascites, not acites
6. Why did you exclude patients with severe ascites? This is an important subgroup receiving
a TIPS intervention.
7. The measurement of the IVCP is not described in detail; location of the tip?
8. Results: Table 1: Child (6.1), MELD (10.4) and liver stiffness (15.8) are exceptional low.
The patients may not be representative for most TIPS patients receiving a TIPS. This should be
mentioned and discussed.
9. Table 2: The difference between the HVPGs and the PPG (gold standard) is substantial
(about 5 mmHg) and significant.  A significant number of patients may have HVPGs below the
threshold of 12 mmHg. Thus, 10 of your patients had baseline HVPG < 10 mgHg and 17 patients
< 12 mmHg (Fig. 2a). Please mention this controversial finding.
10. Table 3: The correlations of F-HVPG and I-HVPG with PPG are not convincing. The WHVP
is probably the cause of the limited correlation with PPG.  Please show WHVP and PVP (blots
and correlations) and discuss results accordingly.
11. Discussion: I believe that your aiming at I-HVPG instead of f-HVPG is of minor importance.
I recommend to focus on the question whether measurement in the hepatic vein can be
recommended at all. The differences in PPG and HVPGs are significant and meaningful.
12. Second page of D., 2. para: You underline the importance of the threshold HVPG. Why didn
´t you follow your own recommendations and performed the TIPS in patients with hv-gradients
well below the threshold of 10-12 mmHg?
13. The study is limited by a low number of patients (subgroup with 18 patients). Please discuss.
14. The study by Silvia-Junor is the only one describing the need for measurement in the
hepatic vein because it correlated with survival after transplantation. In view of the many reports
showing limitations of hv-pressure measurements, this finding needs reconfirmation. Even If the
statement was true, it may not justify applying an inappropriate technique. This is of particular
clinical impact if patients receive pre-interventional hv-measurements to decide for or against
TIPS implantation.
15. Several important references are missing: Lv Y et al, Scientific Reports 2024; Lv Y, Song Q,
Yue Z, et al, Chinese J of Intervent Imaging and Therapy 2023; Lv Y et al, Europ J Radiol 2022.
16. In summary, the results of this study indicate that HVPG measurements (f-HVPG and also I-
HVPG) are not sufficiently accurate when compared with the gold standard (PPG). This is in line
with several recent studies demonstrating several pitfalls of the measurement in the hepatic vein.
This relates to the measurement of the wedge as well as the free hepatic vein pressures. In view
of significant differences in absolute values of hv-pressure gradients and PPG, the significant
correlation cannot justify their use. Since pressure measurements have an important clinical
implication, they must be accurate, a prerequisite which limits the use of hv-measurements. If
possible, authors should also discuss the limitations of IVC measurements and the potential
usefulness of measurement in the right atrium instead.