BackgroundWe examined outcomes in Acute Mesenteric Ischemia (AMI) with the hypothesis that Open Abdomen (OA) is associated with decreased mortality.MethodsWe performed a cohort study reviewing NSQIP emergency laparotomy patients, 2016–2020, with a postoperative diagnosis of mesenteric ischemia. OA was defined using flags for patients without fascial closure. Logistic regression was used with outcomes of 30‐day mortality and several secondary outcomes.ResultsOut of 5514 cases, 4624 (83.9%) underwent resection and 387 (7.0%) underwent revascularization. The OA rate was 32.6%. 10.8% of patients who were closed required reoperation. After adjustment for demographics, transfer status, comorbidities, preoperative variables including creatinine, white blood cell count, and anemia, as well as operative time, OA was associated with OR 1.58 for mortality (95% CI [1.38, 1.81], p < 0.001). Among revascularizations, there was no such association (p = 0.528). OA was associated with ventilator support >48 h (OR 4.04, 95% CI [3.55, 4.62], and p < 0.001).ConclusionOA in AMI was associated with increased mortality and prolonged ventilation. This is not so in revascularization patients, and 1 in 10 patients who underwent primary closure required reoperation. OA should be considered in specific cases of AMI.Level of EvidenceRetrospective cohort, Level III.