Following the work of Dunphy, Mikkelsen in 1957 described atherosclerotic lesions of the celiac and superior mesenteric artery. CMI causes a defined clinical set of symptoms which include abdominal pain, food aversion, and weight loss. The most important factor that determines the severity of CMI is blood flow. Ischemia induced intestinal injury occurs when the intestinal mucosa is deprived of oxygen and other vital nutrients. At least two of these vessels must be compromised to produce symptomatic intestinal ischemia.
Collateral pathways dilate when a major vessel is occluded.
The bowel can tolerate prolonged reduction in blood flow. The main reasons for this finding, is that the only one fifth of mesenteric capillaries are open at any one time. The major cause of CMI is atherosclerosis. An ostial lesion usually begins on the anterior aortic wall and invades the mesenteric lumen of the major arteries that supply the intestine. These atheromatous plaques cause stenosis of the major vessel which reduces profusion to the intestine.