title: Effect of continuous positive airway pressure on day/night rhythm of prothrombotic markers in obstructive sleep apnea.
abstract: OBJECTIVE
  Obstructive sleep apnea (OSA) has been associated with an increased risk of atherothrombotic events. A prothrombotic state might partially explain this link. This study investigated OSA patients' day/night rhythm of several prothrombotic markers and their potential changes with therapeutic continuous positive airway pressure (CPAP).
  
  
  METHODS
  The study included 51 OSA patients [apnea hypopnea index (AHI) ⩾10] and 24 non-OSA controls (AHI<10). Of the 51 OSA patients, 25 were randomized to CPAP and 26 to placebo-CPAP. Twelve blood samples were collected over a 24h period to measure prothrombotic markers. For the apneic patients these samples were collected before treatment and after 3weeks of treatment with either CPAP or placebo-CPAP. Day/night variation in prothrombotic markers was examined using a cosinor analysis.
  
  
  RESULTS
  Compared with controls, OSA patients showed lower mesor (mean) and amplitude (difference between maximum and minimum activity) of D-dimer. In unadjusted (but not in adjusted) analysis, patients showed higher mesor of plasminogen activator inhibitor-1 (p<0.05 in all cases). No significant group differences were seen in mesor and amplitude for either soluble tissue factor or von Willebrand factor, or the acrophase (time of the peak) and periodic pattern for any prothrombotic markers. There were no significant differences in changes of periodic pattern and in day/night rhythm parameters of prothrombotic markers pre- to post-treatment between the CPAP and placebo condition.
  
  
  CONCLUSIONS
  There may be altered day/night rhythm of some prothrombotic markers in OSA patients compared with controls. CPAP treatment for 3weeks did not affect day/night rhythm of prothrombotic markers in OSA patients differently from placebo-CPAP.
authors.affiliation: Department of General Internal Medicine, Inselspital, Bern University Hospital, and University of Bern, Switzerland.
authors.forename: Roland
authors.initials: R
authors.lastname: von Känel
authors.forename: Loki
authors.initials: L
authors.lastname: Natarajan
authors.forename: Sonia
authors.initials: S
authors.lastname: Ancoli-Israel
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Mills
authors.forename: Tanya
authors.initials: T
authors.lastname: Wolfson
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Gamst
authors.forename: José S
authors.initials: JS
authors.lastname: Loredo
authors.forename: Joel E
authors.initials: JE
authors.lastname: Dimsdale
mesh_terms: D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D002940:Circadian Rhythm; D045422:Continuous Positive Airway Pressure / Q000009:adverse effects*; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000628:therapy; D013925:Thromboplastin / Q000032:analysis; D013927:Thrombosis / Q000097:blood / Q000209:etiology*; D014841:von Willebrand Factor / Q000032:analysis
chemical_list: D015415:Biomarkers; D005338:Fibrin Fibrinogen Degradation Products; D017395:Plasminogen Activator Inhibitor 1; C036309:fibrin fragment D; D014841:von Willebrand Factor; D013925:Thromboplastin