title: Functional changes are associated with tracheal structural abnormalities in patients with acromegaly.
abstract: BACKGROUND
  Although impaired pulmonary function and respiratory sleep disorders are described as responsible for increased mortality in acromegalic patients, little is known about the tracheal abnormalities in this group of patients. Thus, the objectives of this study were to describe the tracheal structural abnormalities and correlate these changes with the respiratory function and clinical data of acromegalic patients.
  
  
  METHODS
  This is a cross-sectional study that was carried out at two university hospitals. Twenty acromegalic patients underwent spirometry, forced oscillation technique, and computed tomography (CT) assessments. Dyspnea and daytime sleepiness were assessed using the Modified Medical Research Council (MMRC) scale and the Epworth Sleepiness Scale (ESS), respectively. Forty matched subjects served as controls.
  
  
  RESULTS
  The acromegalic patients exhibited larger median ratios between forced expiratory flow and forced inspiratory flow at 50% of the forced vital capacity (FEF50%/FIF50%) (2.05 vs. 1.06, p = 0.0001) compared with healthy volunteers. In the CT analysis, acromegalic patients exhibited larger median differences between their cervical and thoracic tracheal diameters (Δ tracheal diameters) (3 vs. 1 mm; p = 0.003). An association was found between FEF50%/FIF50% and the following variables: mean resistance (Rm), cervical tracheal diameter, and Δ tracheal diameters. Rm also exhibited a negative correlation with cervical tracheal diameter. Neither the MMRC scale nor the ESS exhibited any significant correlation with large airway obstruction (LAO) indices or with the measured tracheal diameters.
  
  
  CONCLUSIONS
  Acromegalic patients have tracheal structural abnormalities which are associated with functional indicators of LAO but not with clinical data.
authors.affiliation: Post-graduate Program in Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, Brazil; Department of Radiology, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Gustavo Bittencourt
authors.initials: GB
authors.lastname: Camilo
authors.affiliation: Rehabilitation Sciences Post-graduate Program, Augusto Motta University Center, Rio de Janeiro, Brazil; Department of Physiotherapy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Fernando Silva
authors.initials: FS
authors.lastname: Guimarães
authors.affiliation: Post-graduate Program in Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, Brazil; Department of Radiology, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Roberto
authors.initials: R
authors.lastname: Mogami
authors.affiliation: Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Alvaro Camilo Dias
authors.initials: AC
authors.lastname: Faria
authors.affiliation: Post-graduate Program in Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, Brazil; Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil; Post-graduate Program in Clinical and Experimental Physiopathology (FISCLINEX), School of Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Pedro Lopes
authors.initials: PL
authors.lastname: Melo
authors.affiliation: Post-graduate Program in Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, Brazil; Rehabilitation Sciences Post-graduate Program, Augusto Motta University Center, Rio de Janeiro, Brazil.
authors.forename: Agnaldo José
authors.initials: AJ
authors.lastname: Lopes
keywords: acromegaly; respiratory function tests; tomography; trachea