Review for 10.1186/s12876-024-03179-x (2024)

Title: Efficacy of transcatheter arterial embolization in treating nonvariceal gastric remnant
bleeding: a retrospective 5-year study
Version: 0 Date: 12 Jan 2024
Reviewer's report:
Comments to Authors:
This single center retrospective study assessed the efficacy of transcatheter arterial embolization
in treating non-variceal gastric remnant bleeding. During an interval of 5 years, forty-two
patients underwent 47 interventional embolization. Of these, 16 were positive for angiographic
findings, and 26 were negative. Based on arteriography results, different embolic agents were
selected and the technical success rate was 100%. The incidence of postoperative re-bleeding
was 19.1% (9/47), and the overall clinical success rate was 81.0% (34/42). The Logistic
regression shows that omission of embolization of collateral gastric-supplying arteries can
lead to early re-bleeding (OR) of 10.000 (p = 0.014). They conclude that utilizing TAE for
nonvariceal gastric remnant bleeding is safe and effective in the short term (30 days).
The topic is clinically relevant.Nevertheless, the study presents major limitations that need to
be addressed, as follows:
1) In the methods the authors should clearly state the aims of the study and the outcomes.
2) In the methods the authors must clearly provide a definition of all endpoints (clinical success,
technical success, etc).
3) Inclusion criteria: Specify whether all or at least some of the inclusion criteria had to be met.
If all had to be satisfied, inclusion would be too restrictive, reducing the number of patients
eligible for enrollment and limiting the external validity of the study.
4) Exclusion criteria: what does exclusion mean for 'request for surgical treatment'? It does not
make sense. Refusal of the TAE (for any reason) is sufficient as an exclusion criterion.
5) Results: the sample is largely heterogeneous due to:
- Cause of partial gastrectomy (benign, esophago-gastric tumor, etc.)
- Cause of bleeding (erosions, ulcers, neoplasia, vascular malformations, etc.)
- Endoscopic treatment of bleeding (carried out only in 29/42) with patients poorly characterized
regarding the endoscopic treatment used (none, versus mechanical treatment (clips, hemospray ,
glue), or thermal. Furthermore, it is not reported whether before TAE there was a second attempt
at endoscopic hemostasis was made.
- Different angiography method (diagnostic or therapeutic), reason for performing the TAE
(therapeutic, prophylactic or decompressive) and type of embolizing agent used.
The authors should argue these points in the discussion.
6) It is not very clear how the multivariate logistic model has beenperfomed. Table 3 does not
describe the model characteristics for all variables (e.g. B, OR, 95%), but only for the variable
'collateral gastric supplying arteries'.Moreover, variables considered into the models should
not be selected only based on significance to the univariate model, but also guided by clinical
relevance and biological plausibility.Furthermore, the model appears to be overfitted, since there
are too many variables in relation to the events. Ten events per variable is a widely advocated
minimal criterion for sample size considerations in logistic regression analysis.
7) The retrospective study was performed over a 5-year period, despite this the follow-up lasted
only 30 days. The authors should explain the reasons. Recall bias can limit safety data collection
when performed retrospectively. On the other hand, the data on overall mortality can still be
provided over a longer period.
8) Based on these statistical limitations, the results must be presented and suggested with great
caution, advocating prospective multicenter studies. Moreover, I suggest rewriting the paper in
the form of a case series, avoiding any inferential statistics, which can be affected by the study
design, the small sample size and the scarcity of events.
9) The English language is poor and many typos are present. Extensive language editing by a
native speaker is necessary to improve the quality of the manuscript.