Review for 10.1186/s12876-023-02926-w (2023)

Title: Treatment of acute mesenteric ischemia between 2010 and 2020 – a German nation-wide
study
Version: 2 Date: 11 Jun 2023
Reviewer:  Martin Altreuther
Reviewer's report:
Thank you for the opportunity to review this nationwide study about treatment of
acute mesenteric ischemia in Germany between 2010 and 2020 with more than 270.000
hospitalizations. The results indicate the severity of the condition with high mortality, even
though there is a slight decline.
My main criticism is that a great proportion of the actual patients were treated conservatively,
with better survival than the patients treated with open surgery or endovascular intervention. It is
likely, that a considerable proportion of the patients who survived without any intervention did
not have acute mesenteric ischemia, but rather chronic mesenteric ischemia or other conditions
which may cause abdominal pain.
Still, the results cover the recent decade, and are very valuable in understanding the severity of
the actual condition, as well as the fact that we are quite far from giving this patient group the
treatment that is recommended, which is immediate revascularization.
Background: Well written and concise, I have one minor remark
Line 9-10: Treatment regimen depend on the etiology; main goal is to restore blood supply to
the bowel, to prevent infections and to resect nonviable portions of the bowel [2, 6]. Consider
rewording, as treatment not only depends on etiology.
Methods: Well written and detailed. I agree with the categorization of codes as described in
table 1.
However, I could not find the following codes in the online version of the OPS coding system.
Please check, and correct if necessary.
• 8-836.fa
• 8-836.ga
• 8-836.ha
• 8-836.ja
Results: Well written and detailed. I have no additional comments.
Discussion:
I do agree with the description of time trends regarding revascularization with endovascular
intervention or with open surgery, and I do agree with your description of the impact of the
Covid pandemic. However, I feel that you have not addressed  a number of elephants in the
room in your discussion.
In my opinion, the most striking finding in your study is that most patients with the diagnosis of
acute mesenteric ischemia are managed conservatively, with a small decrease during the study
period. Most of the conservatively managed patients are discharged alive, indicating that the
diagnosis of acute mesenteric ischemia is uncertain at best in this subgroup. This should be
addressed more thoroughly in the discussion.
In case the patient is treated invasively after admission, the most common treatment method
is visceral surgery, indicating that bowel necrosis already was established upon admission
or maybe that revascularization after admission was not performed in time. This should be
addressed more thoroughly in the discussion.
Revascularization, either endovascular or with open surgery is rarely performed, even though
this should be the preferred option, increasing from 0.8 % to 2 % over time for endovascular
revascularization and decreasing from 1.6 to 1.1 over time for surgical revascularization. This
probably indicates undertreatment of patients with acute mesenteric ischemia. Whether these
patients are admitted too late, or the lack of treatment is due to limited availability is hard to say,
but the fact that only a small proportion are revascularized should be addressed more thoroughly
in the discussion.