Review for 10.1186/s12876-023-03034-5 (2023)

Title: The value of endoscopically-placed metal clips for transcatheter arterial embolization in
the treatment of recurrent acute non-variceal upper gastrointestinal bleeding
Version: 1 Date: 28 Jul 2023
Reviewer's report:
Dear authors;
The research article is well designed and well written and I greatly appreciate the work done
in this study . However , I have some comments which does not undermine the effort and the
great work that you have done.
Comments on Introduction:
** The authors mentioned that "Empirical embolization was often ineffective" without providing
citation of a reference that support it , and rebleeding rate of 16% in Kim et al is not a high rate
to conclude that it is often ineffective . I suggest modification of this sentence to " empirical
embolization is not usually effective with a rebleeding rate reaches up to 16 % (Kim et al
reference) .
** please use the word embolization instead of embolism in the following sentence "to guide
embolism  during TAE "
** please use only " (Table-1)"  instead of "(For details, see Table 1: Research status of metal
clips in TAE operations in patients with ANVUGIB. )
Comments on materials and methods:
** Can you please replace the following sentence  "Clinical success refers to a follow-up
until 30 days after discharge, the bleeding stopped, and there was no need for additional
endoscopic treatment, repeated embolization or invasive treatment such as surgery ." with the
following sentence "clinical success was defined as control of bleeding with no need for addition
ecdoscopic treatment , repeated embolization or surgery for 30 days after embolization."
** The authors should define what is the Rockall score for readers
** I suggest putting the technical section paragraph before variables paragraph
** I suggest putting the  "Technical success refers to a repeat of the responsible angiogram that
did not show the responsible artery, and no collateral blood supply was formed immediately
after embolization." in the variables paragraph .
** I suggest putting the following "The technical success rate in this study was 100%. " in the
results section.
** the authors mentioned that "For quantitative variables, the strength of association was
calculated by simple binary logistic regression for binary outcomes and was reported as odds
ratios (ORs) with 95% confidence intervals (CIs). " However the reported ORs in Table 4  is a
qualitative categorical Dichotomus variable and not quantitative . More over the ORs  for the
Rockall score is not reported in Table 4.
** please replace the following "For the flow chart, see Fig. 2. " with " Fig.2"
** please replace the following "(for details, see Table 2: Comparison of baseline data). " with
" Table-2"
** Please delete the following sentences  "Comparison of outcome variables " and
"Among all of the patients in this study"  and "In the group comparison,  " . No need for these
phrases before reporting the results . please report the result directly.
**please add the word respectively in the results between parentheses as follow "(82.2% vs
55.2%; respectively, P<0.001 )"
** please delete this sentence "There were statistical significance for all of the differences . " .
it is already mentioned before and P values are  already reported.
** what authors mean by  " metal clip placement rate" . No variable in the table or in the  methods
section  about that .
Comments on discussion:
** please replace the word "by " with " for" in the following sentence "Endoscopic examination
is always required by  these patients"
** please provide a citation for that sentence "there is still a high rebleeding rate after endoscopic
treatment ." and this sentence "Previous case reports have shown that preplaced metal clips under
endoscopy can play a role in locating the responsible blood vessels during TAE . "
** The authors mentioned that "This study is the first controlled study to endoscopically  assess
the impact of metal clips placed at the bleeding site " ; However the study is a retrospective
study not a controlled study and the authors mentioned that "the operators and other factors that
may affect the results cannot be controlled comprehensively" in the limitations of the study .
** please put the word "endoscopically " after the word "placed" in the following sentence " first
controlled study to endoscopically  assess the impact of metal clips placed at the bleeding site "
** the following sentences are already mentioned in results and no nedd for repetition ;
"Compared with the nonclips group, the group with metal clips had a higher clinical success
rate (82.2% vs. 45.0%, P<0.001). The metal clip group also had a lower rebleeding rate (8.2%
vs 27.6%, P=0.039) and additional surgery rate (11.0% vs 20.7%, P<0.001). Consistent with
these results, metal clip marking was also shown to improve the clinical success (OR=3.750,
95CI=1.456-9.659, P=0.004) of TAE in multivariate analysis "
** please use the word "promoting " instead of "protective " in the following sentence "metal
clip placed at the bleeding site was a protective  factor for the success of hemostasis by TAE"
** The following sentence "The mortality rate of the metal clip group was also lower than that
of the no metal clip group, but the difference was not significant (11% vs 24.1%, p=0.146). "
Can be removed from here  as the whole paragraph is discussing why the mortality rate in this
study lower than previous studies.
** the following sentence is repeated and can be removed "Metal clip hemostasis and marking
also proved to be safe "
comment on Tables an figures :
** in Table -2 ; Are preoperative WBCs and Preoperative albumin  data normally distributed ?
If normally distributed you should express it as mean not medians ? if not normally distributed
why you used independent sample t test ?
** in Table-3 ; what authors mean by  total expense and RMB ?
**  in figure-3 ; It is not a diagram . It is a photographic image .