Pathophysiology
Clinical meaning
Chronic mesenteric ischemia (CMI) results from atherosclerotic stenosis of the mesenteric arteries (celiac, SMA, IMA), causing inadequate blood flow to the gut during periods of increased metabolic demand (postprandial state). At least two of the three mesenteric arteries are typically stenosed > 70% before symptoms develop due to extensive collateral circulation. Postprandial pain (intestinal angina) occurs because the diseased vessels cannot increase blood flow to meet the metabolic demands of digestion. Chronic mucosal ischemia leads to villous atrophy, malabsorption, and progressive weight loss. CMI is a precursor to acute mesenteric ischemia, which carries > 50% mortality.