Ischemia
Ischemia is inadequate blood flow to a region of the body, most often due to a constriction of the blood vessels into that area. Lack of oxygen supply can cause tissue necrosis and death if it is not restored. Gastrointestinal (GI) ischemia is caused by blood clots or twisting and strangulation of the GI tract. Signs and symptoms of ischemia include severe abdominal pain, nausea, and vomiting. GI ischemia is a medical emergency that usually requires surgical intervention. X-ray and angiography can diagnose ischemia.
References:
http://en.wikipedia.org/wiki/Ischemia
http://www.fpnotebook.com/SUR7.htm