Bariatric surgery and prevention of cardiovascular events and mortality in morbid obesity: mechanisms of action and choice of surgery.

AIMS: Obesity is associated with increased cardiovascular (CV) morbidity and mortality. Weight loss improves several risk factors for CV diseases, but anti-obesity medications and lifestyle interventions have failed to modify primary CV endpoints. This paper reviews bariatric surgery in prevention of CV diseases and CV mortality, and analyzes the possible mechanisms involved. DATA SYNTHESIS: In morbidly obese patients bariatric surgery results in stable weight loss and in long-term reduction in the prevalence and incidence of obesity-related comorbidities; controlled trials have shown superiority of bariatric surgery over medical therapy in inducing significant weight loss and improvement of CV risk factors. Bariatric surgery induces several metabolic improvements (resolution of type 2 diabetes mellitus, improvement of lipid metabolism and of insulin resistance, reduction of visceral fat, of subclinical endothelial dysfunction and inflammation), and functional improvements (reduction of hypertension, of sympathetic overactivity, of left and right ventricular hypertrophy), which can explain the protective effect towards CV disease. CONCLUSIONS: Reduction of CV diseases is mediated by the pleiotropic effects of weight loss through surgery. Available data do not allow conclusions on the comparative efficacy of different surgical techniques; the choice of the surgical technique for a single patient remains an open question, and it is likely that the degree of prevention of CV diseases depends, among other factors, on the baseline conditions of patients. Large prospective studies are needed to address this issue in morbidly obese patients.