RESUMO
BACKGROUND: Obesity is associated with obstructive sleep apnea-hypopnea syndrome (OSA) and both induce endothelial dysfunction. However, the effect of OSA on endothelial function after bariatric surgery has not been investigated yet. OBJECTIVES: This study aims to evaluate the impact of weight loss on endothelial function in patients with and without obstructive sleep apnea (OSA) in the first 6 months after bariatric surgery. SETTING: This study was conducted at a university hospital, in Brazil. METHODS: The sample consisted of 56 patients homogeneously divided into groups with and without OSA. All patients underwent Roux-en-Y gastric bypass (RYGB), and the diagnosis of OSA was performed by polysomnography. The patients were evaluated preoperatively and 6 months after surgery. The evaluations included anthropometric measures, electrical bioimpedance, clinical symptoms of OSA, and endothelial function (flow-mediated dilation). RYGB improved the anthropometric, bioimpedance, and endothelial function results in both groups. RESULTS: Patients presented a significant clinical improvement in OSA symptoms throughout the study. However, patients with OSA had an improvement in the endothelial function 2.5% lower (p < 0.001) than patients without APNEA syndrome. CONCLUSION: This study demonstrates that the existence of OSA prior to bariatric surgery interferes in the improvement of endothelial function.