title: Clinical heterogeneity of patients with complex sleep apnea syndrome.
abstract: BACKGROUND
  The definition of complex sleep apnea (CompSAS) encompasses patients with obstructive sleep apnea (OSA) who develop central apnea activity upon restitution of airway patency. Presence of arterial hypertension (HTN), coronary artery disease (CAD) and heart failure (HF) have been proposed as risk factors for CompSAS among OSA patients. Using our database of patients with CompSAS, we examined the prevalence of these risk factors and defined other clinical characteristics of patients with CompSAS.
  
  
  METHODS
  Through retrospective search of the database, we examined the medical and clinical characteristics of consecutive patients diagnosed with CompSAS between 11/1/2006 and 6/30/2011 at NorthShore University HealthSystem.
  
  
  RESULTS
  One hundred and fifty patients with CompSAS were identified. Among patients included in the study, 97 (64.7 %) had at least one risk factor for CompSAS, while 53 (35.3 %) did not have any of them. Prevalence of low left ventricular ejection fraction and hypocapnia were low. Therapeutic interventions consisted of several positive airway pressure therapies, mainly adaptive servo ventilation. A hundred and ten patients (73.3 %) complied with recommended therapy and improved clinically.
  
  
  CONCLUSIONS
  Although most patients with CompSAS have cardiac comorbidities, about one third of patients do not have any risk factors of CompSAS prior to sleep testing. Further research on factors involved in development of CompSAS will allow for better tailoring of therapy to pathophysiology involved in an individual case.
authors: Division of Pulmonary and Critical Care Medicine, NorthShore University HealthSystem, 2650 Ridge Avenue, Evanston, IL, USA, tk@medycyna-snu.pl.
authors: Tomasz J
authors: TJ
authors: Kuźniar
authors: Kamilla
authors: K
authors: Kasibowska-Kuźniar
authors: Daniel W
authors: DW
authors: Ray
authors: Thomas
authors: T
authors: Freedom
mesh_terms: D000328:Adult; D015897:Comorbidity; D045422:Continuous Positive Airway Pressure / Q000379:methods; D003324:Coronary Artery Disease / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D007087:Illinois; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012189:Retrospective Studies; D012307:Risk Factors; D020182:Sleep Apnea, Central / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy; D013813:Therapy, Computer-Assisted