Acute mesenteric ischemia: classification, evaluation and therapy

Abstract

Mortality rates of acute mesenteric ischemia still range between 60 and 100%. Unfortunately, retrospective series have not shown any significant improvement in mortality in the past decades. With approximately 50%, superior mesenteric artery (SMA) embolism is the most common form of acute mesenteric ischemia, followed by SMA thrombosis (approximately 25%), nonocclusive mesenteric ischemia (approximately 20%) and mesenteric venous thrombosis (approximately 5%). Clinical presentation may be unspecific, but is often characterised by an initial discrepancy between severe subjective pain and relatively unspectacular findings on physical examination. The key to a better outcome (and the main problem in clinical practice) is early diagnosis. Up to now, helas, there are no simple and noninvasive diagnostic tests of sufficient sensitivity and specificity. Thus, angiography remains the cornerstone of diagnosis and should be performed early in all patients with a risk profile and a clinical presentation suspicious of AMI. The initial therapeutic step in all patients with AMI is resuscitation and a stabilization of circulation. If an advanced stage of ischemia is suspected, broad spectrum antibiotics have to be given. Nonocclusive mesenteric ischemia without signs of peritoneal infarction may be managed by pharmacological vasodilation, and vasodilators are also considered as a valuable supportive treatment option in patients with obstructive mesenteric ischemia. Patients with mesenteric venous thrombosis have to be treated by immediate anticoagulation, followed by laparotomy if peritoneal signs are present. Standard treatment for patients with obstructive mesenteric arterial syndromes is a laparotomy with embolectomy or revascularization and, if indicated, resection of infarcted bowel.--. This review will give an overview on the different forms of mesenteric ischemia and then focus on the diagnosis and on generally recommended forms of treatment.