Sleep breathing disorders and peripheral arterial disease in patients with coronary artery disease

Abstract

Obstructive Sleep Apnea (OSA) is a common disorder in the Sleep Unit. Nocturnal intermittent hypoxemia leads to oxidative stress and endothelial dysfunction and may facilitate the development and progression of atherosclerosis. People with peripheral arterial disease have four to five times more risk of heart attack or stroke but its relationship with OSA is unclear. To determine the prevalence of peripheral arterial disease in patients with a coronary event and its relationship with sleep breathing disorders. The study was performed at the Sleep Unit, Reina Sofia University Hospital, Cordoba, Spain, a third level referral center. The CordioPrev study is an ongoing prospective, controlled trial with a mean follow up of five years duration, including patients with high- risk coronary disease. The study was approved by the Ethics Committee (NCT00924937), and all participants gave written informed consent. Exclusion criteria included severe disease and positive airway pressure treatment before the study. In this cohort of high risk patients, all of them underwent a home respiratory polygraphy. OSA was considered when the apnea-hypopnea index (AHI) ⩾10 events per hour. We also determined the ankle-brachial index to assess lower limb circulation. Values lower than 0.9 where considered pathological. 238 patients were included (mean age 60 ± 9.6 yrs, body mass index 30 ± 3.8). There were 193 (80%) males and 45 (20%) females. 111 subjects (46%) were diagnosed of OSA. The subgroup with higher OSA showed higher body mass index ( p = 0.02) and a lower oxyhemoglobin saturation ( p = 0.03). There were no significant differences in the rate of diabetes mellitus, cholesterol levels and smoking, but hypertension was slightly higher in the OSA group. Both groups had a similar ankle-brachial index, OSA (1.1 ± 0.17) vs non-OSA patients (1.1 ± 0.14), ( p = 0.2). The prevalence of peripheral arterial disease was 4% (10 subjects). No relationship between ankle-brachial index value and respiratory variables (number of events and nocturnal oxyhemoglobin saturation), were observed. In our population the prevalence of peripheral arterial disease assessed by the ankle-brachial index was low and no correlation between ankle-brachial index values and respiratory variables associated with a diagnosis of OSA was observed. At this point it is essential to increase our sample size in order to reject this hypothesis. To Dra Feu Collado for her critical reading of this paper.