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.
Patients usually complain of pain after eating.
Other cause of CMI is nonatherogenic celiac axis compression also known as median arcuate ligament syndrome. The basis for visceral ischemia is the external compression of the celiac axis by the median arcuate ligament. When these symptoms are identified before the onset of infarction, CMI can be treated successfully by visceral artery reconstruction. Pain, which is usually the first sign, is typically gnawing and dull. The location is usually periumbilical or epigastric in location and has its onset between 15 and 30 minutes after meals.