title: Effect of CPAP on arterial stiffness in severely obese patients with obstructive sleep apnoea.
abstract: BACKGROUND
  Obstructive sleep apnoea (OSA) may independently increase cardiovascular risk in obesity. Although there is evidence that arterial stiffness is altered in OSA, knowledge of these effects with continuous positive airway pressure (CPAP) in severe obesity (body mass index (BMI) ≥ 35 kg/m(2)) is limited. This study aimed to explore how arterial stiffness, as measured by the augmentation index (Aix), changed in severely obese patients with OSA who were treated with CPAP and in patients without OSA.
  
  
  METHODS
  Forty-two patients with severe obesity-22 with OSA, 20 without OSA-were recruited at baseline and followed-up after a median of 13.5 months. Pulse wave analysis (PWA) was performed using applanation tonometry at the radial artery to measure augmentation index (Aix), augmentation pressure (AP) and subendocardial viability ratio (SEVR). Cardiovascular parameters and body composition were also measured.
  
  
  RESULTS
  There were significant improvements in Aix, AP (both P < 0.001) and SEVR (P = 0.021) in OSA patients on CPAP compared with subjects without OSA. Epworth scores (P < 0.001), systolic (P < 0.001) and mean arterial pressures (P = 0.002) improved with CPAP. Regression showed that CPAP was significantly associated with change in arterial stiffness from baseline. However, patients with OSA on CPAP continued to have increased arterial stiffness (Aix) (P < 0.001), AP (P = 0.028) and reduced SEVR (P = 0.002) relative to non-OSA patients.
  
  
  CONCLUSIONS
  Although sleepiness and blood pressure improve with CPAP in severe obesity, CPAP alone is not sufficient to modify PWA measures to levels comparable with non-OSA patients. This supports a need for a multifaceted approach when managing cardiovascular risk in patients with severe obesity and obstructive sleep apnoea receiving CPAP therapy.
authors: Department of Obesity and Endocrinology, University of Liverpool, Liverpool, UK. iseetho@liv.ac.uk.|Clinical Sciences Centre, University Hospital Aintree, Longmoor Lane, Liverpool, L9 7AL, UK. iseetho@liv.ac.uk.
authors: Ian W
authors: IW
authors: Seetho
authors: Cancer Research UK Liverpool Cancer Trials Unit, Waterhouse Building, Liverpool, UK.
authors: Rebecca
authors: R
authors: Asher
authors: Department of Respiratory Medicine, University Hospital Aintree, Liverpool, UK.
authors: Robert J
authors: RJ
authors: Parker
authors: Department of Respiratory Medicine, University Hospital Aintree, Liverpool, UK.
authors: Sonya
authors: S
authors: Craig
authors: Department of Respiratory Medicine, University Hospital Aintree, Liverpool, UK.
authors: Nick
authors: N
authors: Duffy
authors: Department of Diabetes and Endocrinology, St. Helens and Knowsley Hospitals, St. Helens, UK.
authors: Kevin J
authors: KJ
authors: Hardy
authors: Department of Obesity and Endocrinology, University of Liverpool, Liverpool, UK.
authors: John P H
authors: JP
authors: Wilding
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D015331:Cohort Studies; D045422:Continuous Positive Airway Pressure; D004739:England; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications / Q000503:physiopathology* / Q000628:therapy*; D017286:Polysomnography; D063177:Pulse Wave Analysis; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology* / Q000628:therapy*; D016896:Treatment Outcome; D059289:Vascular Stiffness / Q000502:physiology*
keywords: Arterial stiffness; CPAP; Obstructive sleep apnoea; Severe obesity
references: J Hypertens. 1998 Dec;16(12 Pt 2):2079-84
references: 9886900
references: Sleep. 1999 Aug 1;22(5):667-89
references: 10450601
references: Hypertension. 2010 Jan;55(1):9-14
references: 19948990
references: Hypertens Res. 2008 Jun;31(6):1109-14
references: 18716358
references: Sleep Med Rev. 2013 Feb;17(1):7-18
references: 22658640
references: Hypertension. 2003 Dec;42(6):1206-52
references: 14656957
references: Br J Clin Pharmacol. 2001 Jun;51(6):507-22
references: 11422010
references: J Hum Hypertens. 2012 Jan;26(1):64-70
references: 21228823
references: Sleep Med Rev. 2003 Feb;7(1):81-99
references: 12586532
references: Eur Heart J. 2004 May;25(9):735-41
references: 15120883
references: Circulation. 1995 Aug 1;92(3):342-7
references: 7634447
references: Eur Heart J. 2006 Nov;27(21):2588-605
references: 17000623
references: Sleep Breath. 2011 Sep;15(3):325-32
references: 20628825
references: Hypertension. 2001 Oct;38(4):932-7
references: 11641312
references: Circulation. 1989 Dec;80(6):1652-9
references: 2598428
references: JAMA. 2001 May 16;285(19):2486-97
references: 11368702
references: J Clin Sleep Med. 2012 Oct 15;8(5):587-96
references: 23066375
references: Am J Epidemiol. 2013 May 1;177(9):1006-14
references: 23589584
references: Curr Opin Cardiol. 2011 Nov;26(6):541-7
references: 21993356
references: JAMA. 2012 May 23;307(20):2161-8
references: 22618923
references: Sleep Med Rev. 2013 Feb;17(1):19-28
references: 22575367
references: Hypertension. 2011 Sep;58(3):417-24
references: 21747042
references: Eur Respir J. 2007 Apr;29(4):720-7
references: 17251237
references: J Sleep Res. 2014 Dec;23 (6):700-708
references: 24731017
references: Clin Exp Pharmacol Physiol. 2008 Aug;35(8):909-15
references: 18346166
references: J Hum Hypertens. 1999 Sep;13(9):625-9
references: 10482972
references: Hypertension. 2005 May;45(5):980-5
references: 15837821
references: Chest. 2007 Sep;132(3):843-51
references: 17573492
references: Hypertens Res. 2011 Jan;34(1):23-32
references: 20962788
references: Proc Am Thorac Soc. 2008 Feb 15;5(2):185-92
references: 18250211