Background: The aim of this multicentre prospective observational study was to identify the incidence, patient characteristics, diagnostic pathway, management and outcome of acute mesenteric ischaemia (AMI). Methods: All adult patients with clinical suspicion of AMI admitted or transferred to 32 participating hospitals from 06.06.2022 to 05.04.2023 were included. Participants who were subsequently shown not to have AMI or had localized intestinal gangrene due to strangulating bowel obstruction had only baseline and outcome data collected. Results: AMI occurred in 0.038% of adult admissions in participating acute care hospitals worldwide. From a total of 705 included patients, 418 patients had confirmed AMI. In 69% AMI was the primary reason for admission, while in 31% AMI occurred after having been admitted with another diagnosis. Median time from onset of symptoms to hospital admission in patients admitted due to AMI was 24 h (interquartile range 9-48h) and time from admission to diagnosis was 6h (1–12 h). Occlusive arterial AMI was diagnosed in 231 (55.3%), venous in 73 (17.5%), non-occlusive (NOMI) in 55 (13.2%), other type in 11 (2.6%) and the subtype could not be classified in 48 (11.5%) patients. Surgery was the initial management in 242 (58%) patients, of which 59 (24.4%) underwent revascularization. Endovascular revascularization alone was carried out in 54 (13%), conservative treatment in 76 (18%) and palliative care in 46 (11%) patients. From patients with occlusive arterial AMI, revascularization was undertaken in 104 (45%), with 40 (38%) of them in one site admitting selected patients. Overall in-hospital and 90-day mortality of AMI was 49% and 53.3%, respectively, and among subtypes was lowest for venous AMI (13.7% and 16.4%) and highest for NOMI (72.7% and 74.5%). There was a high variability between participating sites for most variables studied. Conclusions: The overall incidence of AMI and AMI subtypes varies worldwide, and case ascertainment is challenging. Pre-hospital delay in presentation was greater than delays after arriving at hospital. Surgery without revascularization was the most common management approach. Nearly half of the patients with AMI died during their index hospitalization. Together, these findings suggest a need for greater awareness of AMI, and better guidance in diagnosis and management. Trial registration: NCT05218863 (registered 19.01.2022).

Computed tomography (CT) is widely used in diagnosing acute mesenteric ischemia (AMI), but robust identification of distinctive subtypes and stages of progression is lacking. Systematic literature search in PubMed, Cochrane Library, Web of Science and Scopus was conducted in May 2024. Studies including at least 10 adult patients and reporting radiological diagnosis of AMI versus no AMI or transmural ischemia versus no transmural ischemia were included. Meta-analyses on sensitivity and specificity of different radiological features in diagnosing AMI were conducted. From 2628 titles, 490 studies underwent full text review, and 81 were included in 14 meta-analyses. Diagnostic accuracy of CT angiography (CTA) was high - sensitivity of 92.0% and specificity of 98.8% (I² 45% and 79%, respectively), but lower for other CT protocols (sensitivity 75.8 and specificity 90.5; I² 83%). In most included studies, distinction of subtypes and severity of AMI (non-transmural or transmural) was not possible. Amongst the non-vascular features, absent/reduced bowel wall enhancement provided the best prognostic value (sensitivity 57.9 and specificity 90.1). CTA is the method of choice for diagnosing AMI with high diagnostic accuracy. None of the non-vascular features alone is sufficiently reliable to diagnose AMI or its progression to transmural necrosis, whereas a combination of different radiological features conveys a potential.

The optimal strategy for initial treatment of acute occlusion of superior mesenteric artery (SMA) is debated. The aim of the study was to compare the effectiveness, timelines and outcomes of endovascular versus open surgical treatment in patients with acute SMA occlusion. This was a preplanned substudy of the prospective observational multicenter AMESI (Acute MESenteric Ischaemia) study. Patients with SMA occlusion were divided into surgical and endovascular treatment groups. The surgical group included patients initially subjected to open surgical treatment with surgical or hybrid revascularization or intestinal resection only. The endovascular group included patients initially revascularized endovascularly and was further divided according to treatment effectiveness. Patients were also categorized according to revascularization or no revascularization, and subanalysis performed for different revascularization methods. Baseline and outcome comparisons were made using Fisher and Mann–Whitney U tests. Risk-factors for in-hospital mortality were analysed using a logistic regression model. Of 158 patients 107 had surgical and 51 endovascular treatment. The surgical group had higher baseline illness severity scores, higher C-reactive protein and lactate values. The mortality in the endovascular effective, endovascular insufficient as monotherapy and surgical groups was 2.9%, 41.2% and 45.8%, respectively. In multivariable analysis surgery was not an independent risk factor for in-hospital mortality. The rate of arterial embolism was higher in the endovascular revascularization as monotherapy insufficient treatment group (10/17) compared to the endovascular revascularization as monotherapy effective (5/34) and surgical (27/107) groups. We could not identify useful best thresholds for discriminating between effective and insufficient endovascular treatment. Analysis comparing the effect of any revascularization versus no revascularization on in-hospital mortality did not show a clear benefit of revascularization and the method of revascularization did not independently influence mortality. The beneficial effect of endovascular compared to surgical treatment in unadjusted analyses is largely explained by selection of patients. None of the compared management approaches had an independent effect on mortality. The choice between endovascular and surgical treatment should not be based solely on the time elapsed from symptom onset but rather on the patient’s general condition and possibly on the cause of SMA occlusion.

Background: There are no clinical or laboratory markers that can diagnose acute mesenteric ischemia (AMI) accurately. This study aimed to find differences in clinical and laboratory markers between arterial occlusive AMI and other acute abdominal diseases where AMI was initially suspected. Methods: This was a post hoc study of an international prospective multicenter study where data on patients with suspected AMI were collected. Independent factors associated with arterial occlusive AMI were evaluated in a multivariable logistic regression analysis. Results: The number of patients with arterial occlusive AMI was 231, consisting of thrombotic (n = 104), embolic (n = 61), and indeterminate (n = 66) occlusions. The non-AMI group included 287 patients, of whom 128 had strangulated bowel obstruction. Current smoking (odds ratio [OR] 2.56, 95% confidence interval [CI] 1.31–5.03), hypertension (OR 2.08, 95% CI 1.09–3.97), bowel emptying (OR 3.25, 95% CI 1.59–6.63), and leukocytosis (OR 1.54, 95% CI 1.14–2.08) at admission were independently associated with arterial occlusive AMI compared to the non-AMI group. Conclusions: This study found clinical and laboratory data to be associated with arterial occlusive AMI in patients with suspicion of AMI, which can possibly be of value in screening for arterial occlusive AMI at the emergency department. Further studies are needed to find more accurate diagnostic markers.