Acute Occlusion of the Superior Mesenteric Artery : Diagnosis and treatment

Abstract: Acute occlusion of the superior mesenteric artery (SMA) is a condition associated with high mortality and morbidity. The aim of this thesis is to evaluate diagnostic and therapeutic approaches for acute SMA occlusion. In a prospective study of patients with suspected intestinal ischemia, no biomarker was sufficiently accurate to detect this condition. In a second retrospective study, pancreatic amylase and troponin-I were elevated in a substantial proportion of patients with verified SMA occlusion. In an experimental animal model of acute SMA occlusion, microarray studies of ischemic small bowel wall were used to characterize the mRNA response to ischemia. Thrombospondin, Monocyte Chemoattractant Protein 1 and Gap Junction Alpha 1 were consistently up-regulated in all pigs with intestinal ischemia. Genes encoding previously proposed biomarkers for intestinal ischemia were either up-regulated, such as lactate dehydrogenase and creatine kinase, or down-regulated, such as intestinal fatty acid binding protein and glutathione S-transferase. In a study of the role of computed tomography in the diagnosis of SMA occlusion, it was shown that computed tomography with intravenous contrast was associated with improved survival. A retrospective analysis of all acute SMA revascularizations in Sweden 1999-2006 revealed that D-dimer was elevated in all 35 measured cases.  Endovascular surgery was associated with better outcome than open surgery, both in short and in long term. The presence of postoperative short bowel syndrome was a strong independent risk-factor for decreased long-term survival. Conclusions: Data affirm that D-dimer may serve as an exclusion test for acute SMA occlusion, whereas elevated troponin-I and pancreatic amylase are potential diagnostic pitfalls. Contrast-enhanced computed tomography of the visceral arteries seems to be the best diagnostic method. Endovascular surgery is an option to open surgery in selected cases, and was associated with favourable outcome.