Abstract
Background: Patients with obstructive sleep apnoea (OSA) have increased cardiovascular risk. In these patients, intermittent hypoxia increases sympathetic activity, systemic inflammation and oxidative stress which may all contribute to accelerated atherosclerosis. Our aim was to investigate relationships between carotid intima-media thickness (IMT) and OSA severity, markers of oxidative stress and systemic inflammation.
Methods: 84 subjects [mean age (mean±SD) 47.1±9.7 years, body mass index (BMI) 30.1±4.1 kg/m2] underwent overnight polysomnography (Alice 4, Respironics, Murrysville, USA). Subjects were divided into three groups: no OSA [apnoea-hypopnoea index (AHI) 3.2±1.1 events/hour]; mild-moderate OSA (AHI 15.8±6.7 events/hour), and severe OSA (AHI 48.3±16.0 events/hour). Carotid IMT was assessed by B-mode ultrasound (Philips HD11 XE), arterial pulse wave velocity (PWV) was measured using the automatic Complior device.
Results: Both IMT and PWV increased from subjects with no OSA to patients with mild-moderate, and to those with severe OSA (0.54±0.10 vs 0.59±0.07 vs 0.62±0.11 mm, p=0.037; 8.9±1.0 vs 10.3±1.3 vs 9.8±1.6 m/s, p=0.026, respectively). In addition, circulating oxidized LDL (oxLDL) and lipopolysaccharide binding protein levels increased with OSA severity (p=0.007, p=0.046, respectively). In multivariate analysis, age (p<0.001), oxygen desaturation index (p=0.031) and oxLDL (p=0.005) predicted IMT independently of gender and BMI (r2=0.329).
Conclusions: In patients with OSA, older age, nocturnal intermittent hypoxia and oxLDL were independent correlates of ultrasonographic carotid atherosclerosis.
Support: APVV-0134-11, Ministry of Education, Slovakia.
- Copyright ©ERS 2015