Review for 10.1186/s12876-020-01570-y (2020)

Reviewer’s report
Title: 
Relationship between angiography timing and angiographic visualization of extravasation in
patients with acute non-variceal gastrointestinal bleeding
Version: 
1 
Date: 
14 Aug 2020
Reviewer's report:
This paper is interesting. I recommend its potential publication in this journal, but it needs extensive
revision and clarification. Some comments are listed.
Because this paper is focusing on the non-variceal GIB, please empahsize this point on the title and give
more details about it on the exclusion criteria section.
The authors said "the endoscopic therapy had failed or had been abandoned due to the inability to control
bleeding". Please give the detailed data regarding what kind of endoscopic therapy failed or had been
abandoned. 
The authors collected the data "... comorbid illnesses (hypertension, diabetes, cirrhosis, chronic renal
failure..." in the Methods section. However, in the Table 1, they gave the data regarding chronic liver
diseases. Cirrhosis or chronic liver diseases? This point is important, because cirrhosis is potentially
associated with variceal bleeding.
As a gastroenterologist, I am very interested at blind embolization and its clinical efficacy, because it is
rarely done at my affiliation. In fact, I have discussed with an interventional radiologist at my affiliation
about blind embolization. Give how to do this experienced procedure and more references to be cited in
the Methods section. If you can provide more figures about your interventional procedure and how to
select the target vessel during a blind embolization procedure, it will be better.
The authors said "The angiographic visualization of extravasation was significantly higher in patients with
diabetes (p = 0.036), lower platelet count (p = 0.048), higher highest heart rate (p = 0.002), and AIMS65
score (p = 0.026), and shorter time-to-angiography (p = 0.031)." These words are confusing, especially
"higher highest heart rate". Please find native English speakers or specialists to improve your paper.
Some words about what are associated with angiographic visualization of extravasation are overlapping
between the parts "Baseline characteristics according to the angiographic visualization of extravasation"
and "Clinical and procedural factors associated with 
the angiographic visualization of extravasation".
Please delete one of them or combine them.
The statistical results are confusing. For example, the authors said "The cutoff value of the time-to-
angiography was 4.3 hours, with a sensitivity and specificity of 
39.7% 
and 
41.3%, respectively (p =
0.012). The area under the ROC curve (AUC) was 0.374." Traditionally, an AUC of <0.5 cannot have a P
value of <0.05. Please find statistical experts to check and correct your restuls.
Except for the factors affecting the angiographic visualization of extravasation, the authors should pay
more attention to analysing the factors affecting clinical success or mortality, which are more clinically
significant.
Publons Reviewer Recognition
. Springer Nature can send verification of this review directly to Publons
(a subsidiary of Clarivate Analytics). If you would like to take advantage of this service, please click on
the “Yes” option below. Your name, email address, title of the reviewed manuscript, name of the journal,
and date of your review submission (the “Review Data”) will then be transmitted to Publons upon
publication of the manuscript. If you have already registered at Publons, they will notify you of the receipt
of this review and update your profile 
as per your settings and their policy. If you are not registered with
Publons, you will receive an email from them asking you to register in order for them to be able to
recognize your review on your new profile page. Publons may use the Review Data to generate derivative
metadata for the benefit of Publons and you as a reviewer, carefully considering the sensitivity of such
information. For example, Publons may verify your record as a reviewer by updating your profile
published on its webservice if you have registered for such service or help editors to identify candidate
reviewers. Please find the details of processing in Publons’ privacy policy
https://publons.com/about/terms
Yes
Declaration of competing interests
Please complete a declaration of competing interests, considering the following questions:
1
. 
Have you in the past five years received reimbursements, fees, funding, or salary from an
organisation that may in any way gain or lose financially from the publication of this manuscript,
either now or in the future?
2
. 
Do you hold any stocks or shares in an organisation that may in any way gain or lose financially
from the publication of this manuscript, either now or in the future?
3
. 
Do you hold or are you currently applying for any patents relating to the content of the manuscript?
4
. 
Have you received reimbursements, fees, funding, or salary from an organization that holds or has
applied for patents relating to the content of the manuscript?
5
. 
Do you have any other financial competing interests?
6
. 
Do you have any non-financial competing interests in relation to this paper?
If you can answer no to all of the above, write 'I declare that I have no competing interests' below. If your
reply is yes to any, please give details below.
I declare that I have no competing interests
Reviewer Publication Consent.
 I agree for my report to be made available under an Open Access
Creative Commons CC-BY License (
 http://creativecommons.org/licenses/by/4.0
) if this manuscript is
accepted for publication. Any comments that I do not wish to be included in the published report have
been included as confidential comments to the editor, which will not be published.
If you are not happy for us to publish this report, please contact the editorial office before completing
the review.
If you wish, you can include your name in your published report. Please note you must decide whether
to include your name at the start of the process and confirm this decision whenever prompted. If you
change your decision later, we will not be able to publish your name.
I agree to the terms of the CC-BY 4.0 license; please publish my name with my report.
Is the study design appropriate to answer the research question (including the use of appropriate controls),
and are the conclusions supported by the evidence presented?
Yes
Are the methods sufficiently described to allow the study to be repeated?
No
Is the use of statistics and treatment of uncertainties appropriate?
Yes
Is the presentation of the work clear?
Yes
Are the images in this manuscript (including electrophoretic gels and blots) free from apparent
manipulation?
No