Abstract P133: Obstructive Sleep Apnea May Exacerbate Carotid Artery Stiffness in Individuals With Chronic Obstructive Pulmonary Disease

Abstract

Background: Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are two of the most prevalent respiratory disorders in adults and are both independently associated with increased cardiovascular disease (CVD) risk. The coexistence of OSA in individuals with COPD is termed “overlap syndrome” and occurs in up to 65% of all COPD patients. Individuals with overlap syndrome have more frequent COPD exacerbations, poorer quality of life and increased CVD morbidity than patients with either COPD or OSA alone. COPD and OSA are both independently associated with increased carotid artery stiffness, a predictor of CVD events. However, the interaction of COPD and OSA on carotid artery stiffness remains unknown. We hypothesized that a) carotid artery stiffness would be greater in patients with overlap syndrome than COPD patients without OSA and non-COPD controls and b) overlap syndrome patients that reported using continuous positive airway pressure (CPAP) would have lower carotid artery stiffness than overlap patients not using a CPAP. Methods: Ninety-nine former smokers (n=62 with COPD and n=37 non-COPD controls; age 70 ± 7 yrs; 60M/39F) completed measurements of pulmonary function and common carotid artery stiffness and were retrospectively stratified by self-report of previous clinical diagnosis with OSA. Results: Participants with overlap syndrome had significantly greater carotid β-stiffness than COPD patients without OSA, non-COPD controls with OSA and non-COPD controls without OSA (overlap 5.7 ± 0.71 vs COPD only 3.9 ± 0.20, OSA only 3.6 ± 0.31, controls 3.7 ± 0.23 U; F=6.245, p<0.01) and this difference remained significant after adjustment for body mass index (p=0.01). There were no differences in blood pressure, heart rate, resting oxygen saturation (SpO 2 ) or nocturnal mean SpO 2 in those with overlap syndrome vs. the other groups. Furthermore, there was no difference in carotid β-stiffness between overlap syndrome patients that reported using vs. not using a CPAP (5.98 ± 0.7 vs 5.53 ± 1.9 U, p=0.80). Discussion: These data suggest that OSA exacerbates carotid artery stiffening in COPD patients and that carotid artery stiffness may be one mechanism that mediates the increased CVD risk observed in COPD patients with overlap syndrome.