title: Blood Pressure Increases in OSA due to Maintained Neurovascular Sympathetic Transduction: Impact of CPAP.
abstract: OBJECTIVE
  To test the hypothesis that greater resting sympathetic activity in obstructive sleep apnea (OSA) syndrome would not induce a lesser sympathetic neurovascular transduction.
  
  
  METHODS
  Case-controlled cohort study.
  
  
  METHODS
  33 patients with newly diagnosed OSA without comorbidities and 14 healthy controls.
  
  
  METHODS
  6 months of continuous positive airway pressure (CPAP) treatment for OSA patients and follow-up for 9 healthy controls.
  
  
  RESULTS
  We assessed resting sympathetic outflow and sympathetic neurovascular transduction. Sympathetic activity was directly measured (microneurography) at rest and in response to sustained isometric handgrip exercise. Neurovascular transduction was derived from the relationship of sympathetic activity and blood pressure to leg blood flow during exercise. Despite an elevated sympathetic activity of ∼50% in OSA compared to controls, neurovascular transduction was not different (i.e., absence of tachyphylaxis). After six months of CPAP, there were significant declines in diastolic pressure, averaging ∼4 mm Hg, and in sympathetic activity, averaging ∼20% with no change in transduction.
  
  
  CONCLUSIONS
  Greater sympathetic activity in obstructive sleep apnea does not appear to be associated with lesser neurovascular transduction. Hence, elevated sympathetic outflow without lesser transduction may underlie the prevalent development of hypertension in this population that is well controlled by continuous positive airway pressure treatment.
authors.affiliation: Université Grenoble Alpes, HP2; Inserm U1042, Grenoble, France.|CHU de Grenoble, Clinique Physiologie, Sommeil et Exercice, Grenoble, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Tamisier
authors.affiliation: Cardiovascular Research Laboratory, Spaulding Rehabilitation Hospital, and Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA.
authors.forename: Can Ozan
authors.initials: CO
authors.lastname: Tan
authors.affiliation: Université Grenoble Alpes, HP2; Inserm U1042, Grenoble, France.|CHU de Grenoble, Clinique Physiologie, Sommeil et Exercice, Grenoble, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Pepin
authors.affiliation: Université Grenoble Alpes, HP2; Inserm U1042, Grenoble, France.|CHU de Grenoble, Clinique Physiologie, Sommeil et Exercice, Grenoble, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Levy
authors.affiliation: Cardiovascular Research Laboratory, Spaulding Rehabilitation Hospital, and Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA.
authors.forename: J Andrew
authors.initials: JA
authors.lastname: Taylor
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D016022:Case-Control Studies; D015331:Cohort Studies; D045422:Continuous Positive Airway Pressure; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000517:prevention & control; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D012146:Rest / Q000502:physiology; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology* / Q000628:therapy*; D013564:Sympathetic Nervous System / Q000502:physiology*; D055815:Young Adult
keywords: arterial blood pressure; continuous positive airway pressure; hypertension; obstructive sleep apnea; sympathetic nervous system