title: Patent foramen ovale in severe obstructive sleep apnea: clinical features and effects of closure.
abstract: BACKGROUND
  Patent foramen ovale (PFO) may contribute to nocturnal desaturation in patients with obstructive sleep apnea (OSA), and the effect of PFO closure in OSA is unknown. Our study tested the hypotheses that: (1) patients with severe OSA have a higher prevalence of PFO compared with healthy control subjects, (2) patients with severe OSA with clinically significant PFO experience more nocturnal desaturation than those without, and (3) PFO closure reduces nocturnal desaturation.
  
  
  METHODS
  Patients with severe OSA and healthy control subjects underwent contrast transthoracic echocardiography and transcranial Doppler to detect PFO and determine shunt size. A subgroup of patients with OSA with large shunts underwent percutaneous PFO closure. Polysomnography was performed at baseline and 1, 6, and 12 months postclosure.
  
  
  RESULTS
  One hundred patients with OSA (mean [SD] age, 52 [10] years; apnea-hypopnea index [AHI], 54 [18] events/h) and 50 control subjects (age, 52 [11] years; AHI, 2 [2] events/h) were studied. PFO prevalence was 43% in patients with OSA and 30% in control subjects ( P = .16). Large shunts were detected in 18% of patients with OSA and 6% of control subjects ( P = .049). Patients with OSA with clinically significant shunts had higher oxygen-desaturation index (ODI)/AHI ratios than patients without (ratio, 1.05 [0.27] vs 0.86 [0.26], P = .004). Six patients with OSA underwent PFO closure, which was not associated with a reduction in ODI (baseline, 48 [18]; 12 months, 51 [19] events/h; P = .92) or percentage of the night with arterial oxygen saturation , 90% (baseline, 23% [16%]; 12 months, 20% [22%]; P = .35).
  
  
  CONCLUSIONS
  Patients with severe OSA have a higher prevalence of PFO with large shunts compared with control subjects. The ODI/AHI ratio is increased in patients with OSA with clinically significant shunts. PFO closure does not reduce nocturnal desaturation.
authors.affiliation: National Institute for Health Research Respiratory Biomedical Research Unit, London, England; Academic Unit of Sleep and Ventilation, National Heart and Lung Institute, Royal Brompton Hospital, Imperial College, London, England.
authors.forename: Zarrin F
authors.initials: ZF
authors.lastname: Shaikh
authors.affiliation: Academic Unit of Sleep and Ventilation, National Heart and Lung Institute, Royal Brompton Hospital, Imperial College, London, England.
authors.forename: Jay
authors.initials: J
authors.lastname: Jaye
authors.affiliation: Academic Unit of Sleep and Ventilation, National Heart and Lung Institute, Royal Brompton Hospital, Imperial College, London, England.
authors.forename: Neil
authors.initials: N
authors.lastname: Ward
authors.affiliation: Division of Sleep, Department of Medicine, Brigham and Women's Hospital, Boston, MA.
authors.forename: Atul
authors.initials: A
authors.lastname: Malhotra
authors.affiliation: Echocardiography Department at the Royal Brompton Hospital and Imperial College, London, England.
authors.forename: Manuel
authors.initials: M
authors.lastname: de Villa
authors.affiliation: National Institute for Health Research Respiratory Biomedical Research Unit, London, England.
authors.forename: Michael I
authors.initials: MI
authors.lastname: Polkey
authors.affiliation: Department of Cardiology, Heart Hospital, London, England.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mullen
authors.affiliation: Academic Unit of Sleep and Ventilation, National Heart and Lung Institute, Royal Brompton Hospital, Imperial College, London, England. Electronic address: m.morrell@imperial.ac.uk.
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Morrell
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004452:Echocardiography; D057510:Endovascular Procedures; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000601:surgery; D016896:Treatment Outcome