title: A pilot study investigating the effects of continuous positive airway pressure treatment and weight-loss surgery on autonomic activity in obese obstructive sleep apnea patients.
abstract: BACKGROUND
  We have previously demonstrated that severity of obstructive sleep apnea (OSA) as measured by the apnea-hypopnea index (AHI) is a significant independent predictor of readily-computed time-domain metrics of short-term heart rate variability (HRV).
  
  
  METHODS
  We aimed to assess time-domain HRV measured over 5-min while awake in a trial of obese subjects undergoing one of two OSA therapies: weight-loss surgery (n=12, 2 males, median and interquartile range (IQR) for BMI 43.7 [42.0, 51.4] kg/m2, and AHI 18.1 [16.3, 67.5] events/h) or continuous positive airway pressure (CPAP) (n=15, 11 males, median BMI 33.8 [31.3, 37.9] kg/m2, and AHI 36.5 [24.7, 77.3] events/h). Polysomnography was followed by electrocardiography during wakefulness; measurements were repeated at 6 and 12-18 months post-intervention.
  
  
  RESULTS
  Despite similar measurements at baseline, subjects who underwent surgery exhibited greater improvement in short-term HRV than those who underwent CPAP (p=0.04).
  
  
  CONCLUSIONS
  Our data suggest a possible divergence in autonomic function between the effects of weight loss resulting from bariatric surgery, and the amelioration of obstructive respiratory events resulting from CPAP treatment. Randomized studies are necessary before clinical recommendations can be made.
authors.affiliation: Division of Sleep Medicine, Brigham & Women's Hospital & Harvard Medical School, Boston MA. Electronic address: jpbakker@partners.org.
authors.forename: Jessie P
authors.initials: JP
authors.lastname: Bakker
authors.affiliation: Division of Sleep Medicine, Brigham & Women's Hospital & Harvard Medical School, Boston MA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Campana
authors.affiliation: Division of Sleep Medicine, Brigham & Women's Hospital & Harvard Medical School, Boston MA; Pulmonary and Critical Care Unit, Massachusetts General Hospital, Boston MA.
authors.forename: Sydney B
authors.initials: SB
authors.lastname: Montesi
authors.affiliation: Sleep Disorders Center, Section of Pulmonary & Critical Care, Department of Medicine, University of Chicago, Chicago IL.
authors.forename: Jayshankar
authors.initials: J
authors.lastname: Balachandran
authors.affiliation: Pulmonary & Critical Care Division, University of California San Diego, La Jolla CA.
authors.forename: Pamela N
authors.initials: PN
authors.lastname: Deyoung
authors.affiliation: Pulmonary & Critical Care Division, University of California San Diego, La Jolla CA.
authors.forename: Erik
authors.initials: E
authors.lastname: Smales
authors.affiliation: Division of Sleep Medicine, Brigham & Women's Hospital & Harvard Medical School, Boston MA.
authors.forename: Sanjay R
authors.initials: SR
authors.lastname: Patel
authors.affiliation: Division of Sleep Medicine, Brigham & Women's Hospital & Harvard Medical School, Boston MA; Pulmonary & Critical Care Division, University of California San Diego, La Jolla CA.
authors.forename: Atul
authors.initials: A
authors.lastname: Malhotra
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology*; D050110:Bariatric Surgery; D003131:Combined Modality Therapy; D045422:Continuous Positive Airway Pressure; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity; D010845:Obesity Hypoventilation Syndrome / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy*; D010865:Pilot Projects; D029424:Pulmonary Disease, Chronic Obstructive; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D055815:Young Adult
keywords: Continuous positive airway pressure; Heart rate variability; Obstructive sleep apnea; Weight-loss surgery