Objectives: This study evaluates the effects of uvulopalatopharyngoplasty (UPPP) on serum levels of nitric oxide derivatives (NO(x)) and endothelial function by endothelium dependent flow-mediated dilation (FMD) in obstructive sleep apnea syndrome (OSAS).
Study design: Prospective study.
Subjects and methods: Fifteen healthy subjects and 30 subjects with moderately severe to severe OSAS who desired UPPP were prospectively enrolled. FMD was measured by high-resolution B-mode ultrasonography; serum level of NO(x) from peripheral blood samples was also measured. All subjects participated in sleep studies. These studies were repeated 3 months after UPPP in OSAS patients.
Results: For healthy patients, there was no difference in serum level of NO(x) and FMD between baseline and 3 months later. The serum levels of NO(x) in 14 of 30 patients with OSAS - designated surgical responders - increased from 13.9 +/- 5.5 microM preoperation to 28.9 +/- 8.2 microM postoperatively. FMD increased from 5.2 +/- 5.0 preoperatively to 10.0 +/- 4.7 postoperatively. For the 16 unresponsive patients, serum NOx and FMD remained impaired after UPPP.
Conclusion: Successful treatment of OSAS with UPPP leads to restoration of FMD and normal serum levels of NO(x).