Review for 10.1186/s12876-021-01629-4 (2021)

Reviewer’s report
Title: 
Case series of aortoenteric fistula: A rare cause of gastrointestinal bleeding
Version: 
0 
Date: 
30 Aug 2020
Reviewer's report:
In this retrospective series, the Authors report data on their experience with
Aortoenteric fistula, a rare condition which is often both difficult to diagnose
and to treat. 
While it is certainly interesting to to acquire more information about relatively
rare cases of gastrointestinal bleeding ni order to orient the management of
future patients, 
I have some concerns about the data reporting in this manuscript.
Major issues:
1. First of all, it would be useful to know how many cases of gastrointestinal
bleeding were observed in the same timespan of 14 Years as the 9 cases of
aortoenteric fistula occurred, in order to have an idea of the number of cases
treated by the Center
2. In case of Aortoenteric fistula, the main problem for the physicians is that
symptoms are often initially subtle and may get unrecognised until at same point,
there is a serious manifestation. In the Manuscript , data about the timing
between the onset of first symptoms (and which were the first symptoms) and
the onset of further symptoms and/or major complications are not clearly
reported, I only find a single sentence t the beginning of the results section. I
think these data should be described in the foreground, because this information
would actually help recognise this condition in patients with unspecific
symptoms. Moreover, as concerns secondary fistulas, data about the time
between the implantation of graft/surgery and the onset of symptoms is also
important. 
3. Diagnosis: it is unclear why only six patients underwent gastroscopy and only
four patients underwent colonoscopy, while none of the patients underwent
push-enteroscopy, single/double balloon enteroscopy or capsule endoscopy
considering the high number of negative results. Is it because patients developed
shock and were sent directly to CT? Please specify and comment. 
4. Surgical treatment: this paragraph is rich in information, but extremely
difficult to read and confusing, I suggest rewriting it in a clearer way, maybe
grouping the treatment for primary and secondary cases and the cause of death.
Moreover, also in this case the time between onset of symptoms and death or, if
treated, between intervention and death should be clearly reported in the
manuscript. 
5. Please provide a language revision by native speaker, there are many grammar
and syntax mistakes
Minor comments: 
1. Background: many sentences provide data and classifications with our
references. References should be added
2. Background: I believe that the term "the incidence" may be used incorrectly, is
it a prevalence? Please specify
3. Results: Are "Bacterial pathogen results" are all the results of blood cultures?
Please specify
4. Results: "Ulcer stage A2" please add the reference for this classification
5. Discussion: "The third segment of the duodenum...should be taken seriously",
please reformulate
6. Abbreviations: plase correct the meaning of the abbreviation EGD, which is
correct in the text
7. Figure legends: Figure 3 Thrombosis should probably be replaced by
thrombus?
8. Tables: the presence of so many abbreviations makes it difficult to read the
tables
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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?
Yes
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Yes
Is the presentation of the work clear?
No
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes