Review for 10.1186/s12876-025-04010-x (2025)

Title: Comparative Efficacy of Gelatin Sponge, Microcoils, and NBCA in Arterial
Gastrointestinal Bleeding: A Retrospective Study
Version: 1 Date: 07 Apr 2025
Reviewer's report:
Dear authors,
Take care of the following points:
1. Sample Size Justification
The total sample size (N=68) is small, with subgroups of 22–23 patients each. No power analysis
is provided to justify adequacy for detecting statistically significant differences in outcomes,
particularly for secondary endpoints like mortality.
2.   The retrospective nature introduces risks of selection bias and unmeasured confounders (e.g.,
operator skill, patient comorbidities). These limitations are not sufficiently acknowledged in the
discussion, weakening causal inferences.
3.  The use of ANOVA and chi-square tests for small, unevenly distributed groups may not be
robust. Non-parametric tests (e.g., Kruskal-Wallis, Fisher’s exact) are more appropriate for such
sample sizes.
- Pairwise comparisons lack adjustment for multiple testing (e.g., Bonferroni correction),
increasing the risk of Type I errors.
4.  The 100% clinical success rate in the NBCA group is unusually high. Potential biases
(e.g., exclusion of complex cases, operator expertise) are not addressed, casting doubt on
generalizability.
5. Mortality Analysis Underpowered:
30-day mortality rates (17.39%, 13.04%, 9.09%) are based on very few events (4, 3, and 2 deaths,
respectively). The study lacks power to detect meaningful differences in mortality, rendering
these comparisons speculative.
6. Forrest Classification Misapplication
The Forrest classification is validated for peptic ulcer bleeding, not arterial gastrointestinal
bleeding. The rationale for its use here is unexplained, potentially misclassifying bleeding
severity.
7. Inconsistent Reference Formatting:
References contain formatting errors (e.g., missing italics for journal names, inconsistent use of
en dashes in page ranges). Examples:
- Reference 11: “European radiology, 2008, 18:645-657” lacks italics for the journal name.
- Reference 22: Missing volume number and page range formatting.
8. Ethical Approval Number Format:
The approval ID “2024-IIT-FAST 042” appears non-standard. Clarification is needed to confirm
institutional review board compliance.
9. Unaddressed Operator Variability:
The technical complexity of NBCA use (e.g., glue-to-lipiodol ratio adjustments) may depend
on operator experience, which is not discussed as a potential confounder.
10. Redundant Data Availability Statement:
The statement “available from the corresponding author on reasonable request” is generic.
Specific repositories or access protocols are not mentioned, reducing transparency.
11.   The contributions section states roles like “wrote the main manuscript” and “analysed
results” but lacks specificity (e.g., who designed the study, performed statistical analysis, or
interpreted imaging).
12. Incomplete Complication Reporting:
Postoperative complications (e.g., abdominal pain) are listed, but severity, management, and
long-term consequences (e.g., ischemic sequelae) are omitted, limiting clinical relevance.
13. Unjustified Embolization Protocols:
The rationale for using specific NBCA-to-lipiodol ratios (1:4 or 1:3) is not provided, nor is there
discussion of how these ratios were standardized across cases.
14. Ambiguous Exclusion Criteria
Patients with “coagulopathies or thrombocytopenia” were excluded, but the method for
assessing these conditions (e.g., laboratory thresholds, clinical history) is not detailed.
15. Overinterpretation of Results:
The conclusion advocates a “paradigm shift” favoring combination therapies, but the
retrospective design and small sample size preclude definitive recommendations. Greater
caution in framing clinical implications is warranted.
16. Missing Conflict of Interest Clarification:
While authors declare no conflicts, the use of specific products (e.g., Glubran-2, Cook Medical
microcoils) should include a statement confirming no financial ties to manufacturers.