title: Nasal nitric oxide as a marker of sinus mucosal health in patients with nasal polyposis.
abstract: BACKGROUND
  Reduced nasal nitric oxide (nNO) has been shown in patients with chronic rhinosinusitis (CRS) but its clinical significance remains uncertain. The objective of this study was to measure nNO changes in patients undergoing endoscopic sinus surgery (ESS) for CRS and to explore its relationship to clinical measures of sinus mucosal health postoperatively.
  
  
  METHODS
  This was a prospective study of CRS patients undergoing ESS. Patients had the following measurements at baseline and at 1 and 6 months post-ESS: nNO levels, Lund-Kennedy Endoscopy Score (LKES), and 22-item Sino-Nasal Outcome Test (SNOT-22) score. Statistical analysis was performed using GraphPad Prism 6.
  
  
  RESULTS
  Thirty-nine patients were enrolled, of these 84.6% had CRS with nasal polyps. Baseline Lund-Mackay computed tomography (CT) score was 16.9 ± 5.1. There was a statistically significant increase in nNO levels from baseline to 1 month and 6 months postoperatively (p < 0.0001). The SNOT-22 and LKES followed a similar trend with a significant and sustained improvement at 1 month and 6 months post-ESS (p < 0.0001). Subgroup analysis revealed that changes in nNO were driven by the polyp cohort because nonpolyp patients had no significant changes in their nNO postoperatively. No correlation was found between nNO levels and SNOT-22. However, a significant negative correlation was found between nNO and LKES (p < 0.0001), suggesting healthier sinus mucosa was associated with higher nNO levels.
  
  
  CONCLUSIONS
  This is the first study to show that nNO levels may be a marker of sinus mucosal health following ESS in patients with polyps. This has important implications for nNO in its potential etiologic role in mediating ongoing sinus inflammation.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.|The Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: John M
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Carmen L
authors.initials: CL
authors.lastname: McKnight
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Theresa
authors.initials: T
authors.lastname: Aves
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Yip
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Amandeep S
authors.initials: AS
authors.lastname: Grewal
authors.affiliation: The Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada.|Division of Respirology, Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Samir
authors.initials: S
authors.lastname: Gupta
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism*; D002908:Chronic Disease; D004724:Endoscopy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000378:metabolism* / Q000601:surgery; D009298:Nasal Polyps / Q000175:diagnosis* / Q000601:surgery; D009569:Nitric Oxide / Q000378:metabolism*; D011446:Prospective Studies; D012220:Rhinitis / Q000175:diagnosis* / Q000601:surgery; D012852:Sinusitis / Q000175:diagnosis* / Q000601:surgery
chemical_list: D015415:Biomarkers; D009569:Nitric Oxide
keywords: biomarker; chronic rhinosinusitis; endoscopic sinus surgery; endoscopy; eosinophilic rhinitis and nasal polyposis