Mesenteric ischemia overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
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Overview
Historical Perspective
Classification
Pathophysiology
The factors that regulate the intestinal blood flow play a vital role in the development of mesenteric ischemia. Mucosa of the intestines has a high metabolic activity and accordingly a high blood flow requirement. The majority of blood supply of the intestine comes from the superior mesenteric artery, with a collateral blood supply from superior and inferior pancreaticoduodenal arteries (branches of the celiac artery) as well as the inferior mesenteric artery. The splanchnic circulation (arteries supplying the viscera) receives 15-35% of the cardiac output, making it sensitive to the effects of decreased perfusion. Mesenteric ischemia occurs when intestinal blood supply is compromised by more than 50% of the original blood flow without activation of adaptive responses. This can lead to disruption of mucosal barrier, allowing the release of bacterial toxins (present in the intestinal lumen) and vasoactive mediators which ultimately lead to complete necrosis (cell death) of the intestinal mucosa. This can further progress to depression in myocardial activity, sepsis, multiorgan failure, and without prompt intervention, even death.
Causes
Mesenteric ischemia (MI) is classied into various subdivisions based on the difference in pathogenesis and treatment of each type. MI is primarily classified into acute and chronic, on the basis of severity; occlusive and non occlusive based on their pathophysiology.