Obstructive sleep apnoea
Published Date: 19th July 2016
Publication Authors: Hardy KJ
Introduction: Obstructive sleep apnoea (OSA) is associated with obesity, hypertension and cardiovascular disease. Arterial stiffness has been proposed as a marker of cardiovascular disease risk. We determined whether severely obese patients with newly diagnosed OSA without previous cardiovascular disease have increased arterial stiffness compared with BMI-matched controls.
Methods: 72 patients(35 females), age 47.8±9.8 years, mean BMI 40.9±7.2 kg/m2 underwent a night respiratory polysomnographic study to assess for OSA. Pulse wave analysis used applanation tonometry at the radial artery. Augmentation index at HR75 (Aix), Augmentation pressure (AP) and subendocardial viability ratio (SEVR) were derived from waveforms. OSA patients were studied prior to CPAP.
Results: Groups [OSA 47, controls 25], [Apnoea-hypopnoea Index (AHI) 23.8±10.6 vs 2.6±1.0] were matched for age [OSA 46.7±9.4 years vs control 49.6±10 years(ns)] and BMI [42.0±7.8 kg/m2 vs 40.0±5.8 kg/m2 (ns)]. Obese OSA patients demonstrated increased arterial stiffness, augmentation pressure and SEVR compared with controls (OSA Aix 23.2±5.2% vs control 11.3±5.2%; OSA AP 12.8±6.3 mmHg vs control 6.5±4.1 mmHg; OSA SEVR 149±14% vs control 171±12%) all P<0.001. Aix was associated with mean arterial blood pressure (MAP) (r=0.31, P=0.003) and AHI (r=0.436,P<0.001). On multivariate analysis with Aix designated as dependent variable and including age, BMI, systolic BP, diastolic BP, MAP, total cholesterol and AHI as independent variables, AHI emerged as an independent predictor of arterial stiffness [β=0.42±0.05,P<0.001].
Conclusions: Severely obese patients without cardiovascular disease or hypertension but who have OSA have increased arterial stiffness. The observed association between the Aix and MAP may relate to underlying arterial stiffness augmenting central pressures, potentially increasing cardiovascular risk.
Seetho, I; Parker, R; Craig, S; Duffy, N; Hardy, K; Wilding, J. (2013). Obstructive sleep apnoea is associated with increased arterial stiffness in severe obesity . Obesity Facts. 6 (Suppl 1), 130
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