title: Derived Arterial Stiffness is Increased in Patients with Obstructive Sleep Apnea and Periodic Limb Movements during Sleep.
abstract: OBJECTIVE
  Both periodic limb movements during sleep (PLMS) and obstructive sleep apnea (OSA) have been associated with increased risk of cardiovascular disease (CVD). OSA has also been linked to increased large arterial stiffness, which is considered an independent risk factor for CVD. We utilized a previously validated index of large artery stiffness (SIDVP) derived from the digital volume pulse (DVP) to seek comparison in patients with PLMS and OSA.
  
  
  METHODS
  Forty-nine adult male subjects, without known comorbidities that could affect arterial stiffness or on vasoactive medication, were retrospectively identified and categorized into controls (n = 8), PLMS (n = 13), OSA (n = 17), and OSA/PLMS (n = 11). The cutoff for PLMS was a periodic limb movement index (PLMI) > 15 events/h, and for OSA an apnea-hypopnea index (AHI) > 10 events/h. SIDVP was derived from the raw data of photoplethysmography of the nocturnal polysomnography, averaged for 2 min prior to sleep study initiation (baseline), after completion in the morning, and every half hour after sleep onset.
  
  
  RESULTS
  The groups were age/body mass index-matched. Controls showed lower baseline, morning, and overall SIDVP compared to the other groups (p < 0.01). Patients with PLMS (PLMI: 50.69 ± 9.7 events/h) and the OSA group (AHI: 29.7 ± 2 events/h) demonstrated similar overall SIDVP (6.78 ± 0.08 versus 6.94 ± 0.04, respectively, p = 0.5), whereas the OSA/PLMS (AHI: 29.35 ± 8, PLMI: 50.63 ± 7.2) group demonstrated the highest (7.40 ± 0.06, p < 0.001).
  
  
  CONCLUSIONS
  Based on an easily reproducible and applicable marker of large arterial stiffness, patients with significant PLMS had higher SIDVP when compared to controls and comparable to those with moderate/severe OSA. The OSA/PLMS group had the highest SIDVP, implying a possible additive effect of OSA and PLMS on arterial stiffness.
authors.affiliation: Guy's and St Thomas' NHS Foundation Trust, UK.
authors.forename: Panagis
authors.initials: P
authors.lastname: Drakatos
authors.affiliation: Guy's and St Thomas' NHS Foundation Trust, UK.
authors.forename: Sean
authors.initials: S
authors.lastname: Higgins
authors.affiliation: Guy's and St Thomas' NHS Foundation Trust, UK.|University Hospital of Padova, Italy.
authors.forename: Martino F
authors.initials: MF
authors.lastname: Pengo
authors.affiliation: Guy's and St Thomas' NHS Foundation Trust, UK.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Kent
authors.affiliation: Guy's and St Thomas' NHS Foundation Trust, UK.
authors.forename: Rex
authors.initials: R
authors.lastname: Muza
authors.affiliation: University Hospital of Patras, Greece.
authors.forename: Kiriakos
authors.initials: K
authors.lastname: Karkoulias
authors.affiliation: Guy's and St Thomas' NHS Foundation Trust, UK.|King's College, London, England.
authors.forename: Guy
authors.initials: G
authors.lastname: Leschziner
authors.affiliation: Guy's and St Thomas' NHS Foundation Trust, UK.|King's College, London, England.
authors.forename: Adrian
authors.initials: A
authors.lastname: Williams
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000209:etiology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020189:Nocturnal Myoclonus Syndrome / Q000150:complications / Q000503:physiopathology*; D017156:Photoplethysmography; D017286:Polysomnography; D012189:Retrospective Studies; D012307:Risk Factors; D012890:Sleep / Q000502:physiology; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology*; D059289:Vascular Stiffness / Q000502:physiology*
keywords: arterial stiffness; cardiovascular risk; digital pulse volume; periodic limb movements during sleep; stiffness index