Predictors of Successful Weight Restoration in the Treatment of Superior Mesenteric Artery Syndrome: A Systematic Review.

Background/Objectives: Treatment for superior mesenteric artery (SMA) syndrome can include either weight restoration (conservative management) or surgical intervention, with the latter recommended when individuals fail conservative management. However, reasons for failure of conservative management are poorly understood. This systematic review seeks to better understand predictors of treatment outcomes for malnourished individuals with SMA syndrome, specifically regarding weight restoration and behavioral health intervention, and to better understand why individuals fail conservative management. Methods: Medline, Embase, and Web of Science were searched for articles that assessed treatment interventions for SMA syndrome in malnourished individuals. Results: Seventy-three articles (n = 189 malnourished individuals with SMA syndrome) were included in the final review. Most of the articles (n = 57) had an increased risk of bias as the amount of weight gain with treatment was not explicitly defined and thus the attribution of outcome for "failure" of conservative management could not be ascribed. Modest weight gain (mean 5.64 kg [12.1% body weight increase] or 1.3 kg/m² body mass index increase [9.4% increase in ideal body weight]) was associated with positive outcomes of conservative management. Psychological care also positively impacted treatment outcomes, especially for individuals with comorbid psychiatric conditions. Conclusions: Patients who achieve even modest weight gain have resolution of their SMA-related symptoms without a need for surgical intervention. Psychological treatment should be included for any patient struggling to achieve adequate weight restoration, with subsequent improved outcomes, given the high frequency of comorbid mental health illnesses, especially eating disorders.