Non-Occlusive Mesenteric Ischemia in Aortic Surgery: What You Need to Know.

Abstract

Background: Nonocclusive mesenteric ischemia (NOMI), a subtype of acute mesenteric ischemia, is primarily caused by mesenteric arterial vasoconstriction and decreased vascular resistance, leading to impaired intestinal perfusion.Commonly observed after cardiac surgery, NOMI affects older patients with cardiovascular or systemic diseases, accounting for 20-30% of acute mesenteric ischemia cases with a mortality rate of ∼50%. This review explores NOMI's pathophysiology, clinical implications in aortic dissection, and the unmet needs in diagnosis and management, emphasizing its prognostic significance.

Methods: A comprehensive literature review was conducted using multiple electronic databases to extract relevant data and information.

Results: NOMI is a life-threatening condition characterized by mesenteric vasoconstriction and reduced splanchnic blood flow, often triggered by cardiac surgery, haemodialysis, or hypotensive episodes. Epidemiological studies highlight its prevalence in ICU settings, with a high mortality rate linked to delayed diagnosis and systemic hypoperfusion. Risk factors include advanced age, vasopressor use, and inflammatory markers. Biomarkers such as I-FABP, citrulline, and D-lactate show potential for early detection but lack robust clinical validation. Management includes fluid resuscitation, vasodilators, and surgical intervention for bowel necrosis. Emerging endovascular approaches show promise but are limited to select cases without bowel infarction. This review underscores the critical need for timely diagnosis, risk factor identification, and tailored interventions to improve outcomes.

Conclusion: NOMI remains poorly understood despite advances in surgical and perioperative care. Its pathophysiology, linked to cardiopulmonary bypass and intraoperative factors, requires heightened clinical vigilance. Limited evidence underscores the need for a multidisciplinary approach involving surgeons, radiologists, and anaesthetists to improve diagnosis, management, and outcomes in aortic surgery patients. Figure 1. Schematic illustration of morphological and haemodynamic patterns of mesenteric ischaemia. The aortic type (A) and branch type (B) cause significant malperfusion, while mild compression of the true lumen (TL) or double tract perfusion do not cause malperfusion. AB-AO abdominal aorta, FL false lumen, SMA superior mesenteric artery. Reproduced from Orihashi et al. [REF] with copyright permission obtained.