The challenging diagnosis of ICU-related Mesenteric Ischaemia: a prospective, observational, multicentre cohort

Background: The diagnosis of acute mesenteric ischemia (AMI) is challenging, especially in the intensive care unit (ICU), where non-occlusive mesenteric ischemia (NOMI) predominates. In ICU patients, contrast-enhanced computed tomography (CT) provides limited diagnostic accuracy, and no single biomarker is sufficiently reliable. Transmural digestive necrosis, revealed as necrotic bowel (NB) during surgical exploration, is irreversible and requires bowel resection. We proposed an approach combining several clinical, biological, and therapeutic parameters to predict the presence of NB in ICU patients with high suspicion of AMI. Methods: We conducted a prospective observational study in three ICUs. All consecutive patients with suspected AMI were enrolled. Patients with NB identified during surgical exploration were compared with those without NB. Patients who survived without undergoing surgery were considered not to have NB. Multivariable logistic regression analysis was used to identify parameters independently associated with NB. Results: A total of 202 patients were included. Among them, 74 (37%) had NB (including 70 with NOMI and 4 with occlusive AMI), while 128 (63%) did not. In the multivariable analysis, age (OR 1.068, 95% CI 1.027-1.111, p = 0.001), active fluid removal (OR 3.148 (1.19-8.33), p = 0.021), signs of gastrointestinal injury (3.432 (1.082-10.885), p = 0.036), need for renal replacement therapy (OR 3.834 (1.457-10.01), p = 0.006), and lactate dehydrogenase (log) at the time of AMI suspicion (OR 7.135 (2.1-24.235) p = 0.002) were independently associated with NB. Among biomarkers, lactate dehydrogenase, showed the highest area under the ROC curve. Conclusions: This is the first study to propose a combined approach for predicting NB in ICU patients with suspected AMI. When AMI is highly suspected, surgical exploration should be considered in patients presenting with signs of gastrointestinal injury in a context of fluid removal or renal replacement therapy, as these findings are strongly suggestive of necrotic bowel.