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: 
2 
Date: 
04 Oct 2020
Reviewer's report:
The authors are reporting interesting data. I recommend the publication in this journal. However, the
current revisions are not satisfactory. It should be more important to explore the factors associated with
clinical success and mortality in patients with acute non-variceal gastrointestinal bleeding who are treated
with angiographic embolization. In the authors' responses, the authors said "angiographic visualization of
extravasation decreased the clinical success rate (ORs: 0.401, 95% CI:0.165-0.974)" and "clinical success
decreased the 30-day all-cause mortality (ORs: 0.001, 95% CI: 0.000-0.109)". If so, this paper is of little
significance. I guess that your statistical analysis may be problematic. Additionally, another cause for this
unexpected phenomenon should be that negative "angiographic visualization of extravasation" indicates
less severe disease and better outcomes. I suspected that some cases of negative "angiographic
visualization of extravasation" 
may have conservative therapy alone, but lower requirement of
embolization.
I suggest that the authors should separately analyze the risk factors for the outcomes (mortality) in patients
with and without "angiographic visualization of extravasation".
Procedures regarding blind embolization are still unclear. How to select a target vessel to release your
embolization agent should be introduced in details. More detailed information should be given in the
figure legend.
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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?
No
Is the presentation of the work clear?
No
Are the images in this manuscript (including electrophoretic gels and blots) free from apparent
manipulation?
Yes