الفهرس 
Small IntestineOnly 14 pages are availabe for public view
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Abstract
Chronic mesenteric ischemia (CMI) is a condition caused by occlusive disease of the mesenteric vessels and occurs when the blood supply is insufficient to meet the metabolic demands of the bowel, resulting from increased motility, secretion, and absorption after meals. The clinical manifestation of CMI is exceedingly rare. It generally occurs in patients over 60 years of age, and is threefold more frequent in women.
Although the prevalence of mesenteric artery stenosis (MAS) is high, symptomatic chronic mesenteric ischemia (CMI) is rare. The collateral network in the mesenteric circulation {between the three main visceral arteries (CA, SMA, and IMA) and the internal iliac arteries}, a remnant of the extensive embryonal vascular network, serves to prevent most cases of ischemia. This explains the high incidence of MAS and relative rarity of cases of CMI. So the majority of patients with symptoms of CMI have significant stenosis or occlusion of at least two of the three mesenteric arteries and most subjects with single vessel mesenteric stenosis do not develop ischemic complaints.
Chronic mesenteric ischaemia is a rare and potentially fatal disease most commonly due to atherosclerotic stenosis or occlusion of two or more mesenteric arteries in 90% of cases; less frequent causes are mesenteric vasculitis (MV) and fibromuscular dysplasia (FMD).CMI poses thus a diagnostic challenge to the medical practitioner. There are numerous case reports of patients whose symptoms are vague and are treated for other causes than the actual underlying problem of CMI, so it requires careful history taking to suspect mesenteric ischemia in a patient with vague abdominal symptoms and the patient has nonspecific finding in physical examination. So we should have a high index of suspicion confirmed by one or more diagnostic studies, such as duplex ultrasonography (DUS), magnetic resonance angiography (MRA), computed tomography angiography (CTA), or conventional aortography.
Duplex ulrasonography is the screening method of choice of CMI. CTA is an emerging diagnostic test with high sensitivity and specificity in the setting of both acute and chronic mesenteric ischemia and should be considered the first-line imaging test. However; conventional angiography is the gold standard test for these patients. Magnetic resonance angiography (MRA) offers a second modality for obtaining anatomic imaging of the visceral vessels aside from CTA.
Recently, Visible light spectroscopy (VLS) is a new technique that enables non-invasive measurements of mucosal capillary hemoglobin oxygen saturations during endoscopy, also jejunal tonometry has been used with additional diagnostic value.Once CMI is diagnosed and manifests with symptoms, the goal of therapy for these patients is the prompt restoration of blood flow to prevent bowel infarction, perforation, sepsis, and death.
Since 1958, Open treatment (OT) of symptomatic CMI has been the gold standard of management. However, nowadays, mesenteric angioplasty and stenting is the first choice of treatment in patients with CMI who have suitable lesions, independent of their clinical risk. The ideal lesion for angioplasty and stenting is a short, focal stenosis or occlusion with minimal to moderate calcification or thrombus.
The decision between open surgical (OS) and endovascular therapy (ET) is nuanced and a careful review of preprocedure CTA with attention to lesion anatomy, nutritional status, and life expectancy. ET is generally preferred as a first choice of treatment for CMI given the low rates of preoperative morbidity and mortality compared to OS.
In most recent results of studies about the management of CMI clarified that ER has similar preoperative mortality and shorter hospitalization but higher rate of restenosis requiring reintervention compared with OR. Patients with ER who required reintervention appear to have longer lesions as well as higher rates of aortic occlusive disease on preoperative angiography. Patients crossed over from ER to OR had higher preoperative mortality than either primary open or endovascular patients. These findings may guide treatment selection in patients with CMI undergoing ER or OR.