title: Obstructive sleep apnea can be provocative for right-to-left shunting through a patent foramen ovale.
abstract: OBJECTIVE
  Under particular conditions, a patent foramen ovale (PFO) can potentially give rise to ischemic stroke by means of paradoxical embolization, due to right-to-left shunt. Our study aimed to evaluate the presence of right-to-left shunt in patients with obstructive sleep apnea syndrome (OSAS) and diagnosed PFO during sleep.
  
  
  METHODS
  Assessment of provocative-only PFO and concomitant OSAS. Evaluation of right-to-left shunting during sleep by means of transcranial doppler with contrast medium injected in the cubital vein.
  
  
  METHODS
  10 consecutive patients affected by PFO detectable only under Valsalva maneuver during wakefulness and affected by OSAS (mean age 52.8 +/- 10.7 years).
  
  
  METHODS
  Patients underwent transcranial doppler with injection of agitated saline solution mixed with air during normal breathing and during periods of apnea/hypopnea in nocturnal sleep.
  
  
  RESULTS
  Right-to-left shunt was present in 9 patients out of 10 and appeared during obstructive apneas longer than 17 seconds. In 1 out of 10 patients, only hypopneas occurred and no right-to-left shunt could be shown. The number of microembolic signals detected during periods of nocturnal apnea was positively correlated with the number detected during Valsalva maneuver in wakefulness (p<0.0001).
  
  
  CONCLUSIONS
  In the nocturnal sleep period, right-to-left shunt can occur during single obstructive apneas in patients with OSAS and concomitant presence of PFO. This can be a risk factor for cerebrovascular diseases. This risk could probably increase proportionally to the respiratory disturbance index of these patients.
authors.affiliation: Center of Sleep Medicine, DISMR, University of Genoa, Italy.
authors.forename: Manolo
authors.initials: M
authors.lastname: Beelke
authors.forename: Silvia
authors.initials: S
authors.lastname: Angeli
authors.forename: Massimo
authors.initials: M
authors.lastname: Del Sette
authors.forename: Fabrizio
authors.initials: F
authors.lastname: De Carli
authors.forename: Paola
authors.initials: P
authors.lastname: Canovaro
authors.forename: Lino
authors.initials: L
authors.lastname: Nobili
authors.forename: Franco
authors.initials: F
authors.lastname: Ferrillo
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D004621:Embolization, Therapeutic / Q000009:adverse effects*; D005260:Female; D006344:Heart Septal Defects, Atrial / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000209:etiology*; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods; D014636:Valsalva Maneuver; D014851:Wakefulness
chemical_list: D003287:Contrast Media