Peri-operative endothelial dysfunction in patients undergoing minor abdominal surgery

BACKGROUND: Myocardial injury after noncardiac surgery is common and associated with major adverse cardiac events. Surgery induces acute endothelial dysfunction, which might be central in the pathophysiology of myocardial injury; however, the relationship between surgical stress and endothelial function remains incompletely understood. OBJECTIVES: This study aimed to assess the acute peri-operative changes in endothelial function after minor elective abdominal surgery. DESIGN: A prospective, observational, single-centre study. SETTING: A university hospital from February 2016 to January 2017. PATIENTS: Sixty patients undergoing elective minor abdominal surgery. MAIN OUTCOME MEASURES: The change in endothelial function, expressed as the reactive hyperaemia index (RHI), was assessed by non-invasive digital pulse tonometry. RHI, biomarkers of nitric oxide bioavailability and oxidative stress were assessed prior to and 4 h after surgery. RESULTS: RHI decreased significantly from 1.93 95% confidence interval (95% CI 1.78 to 2.09) before surgery to 1.76 (95% CI 1.64 to 1.90), P = 0.03, after surgery. The nitric oxide production, L-arginine/asymmetric dimethylarginine, decreased significantly from a ratio of 213.39 (95% CI 188.76 to 241.2) to a ratio of 193.3 (95% CI 171.82 to 217.54), P = 0.03. Plasma biopterins increased significantly after surgery, while the ratio between tetrahydrobiopterin and dihydrobiopterin was unchanged. Total ascorbic acid decreased significantly after surgery (P < 0.001), while its oxidation ratio was unchanged. CONCLUSION: Elective minor abdominal surgery impaired systemic endothelial function early after surgery. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02690233.