Musa Murat Çalışkan, Tahir Talat Yurttaş, Selim Doğan, Ufuk Oğuz İdiz, Kenan Büyükaşık, Taşkın Rakıcı, Mert Mahsuni Sevinç
Background/Objectives: Acute mesenteric ischemia (AMI) resembles non-vascular intestinal ischemia (NSII) and non-specific abdominal pain (NSAP) at presentation yet carries 50-80% mortality. We tested how well admission data separate these conditions and predict in-hospital mortality, the primary endpoint. Methods: We studied 197 consecutive adults (2015-2021): AMI (n = 61), NSII (n = 62), and NSAP controls (n = 74). Admission demographics, comorbidities, laboratory markers, the Mannheim Peritonitis Index (MPI), and APACHE-II were compared by ROC/DeLong analysis and multivariable logistic regression (STROBE). Results: AMI had more atrial fibrillation, thromboembolism, chronic kidney disease (CKD), and dyslipidemia (p ≤ 0.028) and higher in-hospital mortality than NSII (47.5% vs. 16.1%; p < 0.001). Inflammatory ratios, lactate, and albumin separated AMI from NSAP well (AUC up to 0.93) but from NSII modestly (lactate, 0.672). APACHE-II (AUC 0.861) and MPI (0.810) predicted in-hospital death and improved combined (0.897; DeLong p = 0.014). Independent predictors were MPI (adjusted odds ratio 1.14, 95% CI 1.06-1.23), CKD (3.72, 1.25-12.10), and arterial lactate (1.20, 1.03-1.45). Conclusions: A composite admission panel was internally consistent but hypothesis-generating, not a triage tool ready for clinical use. CT angiography remains essential, since these markers cannot separate vascular from non-vascular ischemia; prospective external validation is required.