Assessment of carotid artery intima-media thickness in patients with obstructive sleep apnoea.

OBJECTIVE

This study compares the carotid intima-media thickness (CIMT) in different severity of obstructive sleep apnoea (OSA) patients and assesses the role of OSA in carotid artery vasculopathy with control of multiple co-morbidities.

STUDY

DESIGN

Prospective case-control study.

SETTING

Tertiary referral centre.

PARTICIPANTS

This study recruited 36 volunteers without the complaints of sleep-disordered breathing, 27 patients with mild-moderate OSA and 39 patients with severe OSA.

MAIN OUTCOME MEASURES: The CIMT was measured using a Toshiba Aplio 500 ultrasound system (Otawara, Japan) with a 5-14 MHz L probe.

RESULTS

Bilateral and mean CIMT in healthy control, mild-moderate OSA and severe OSA were 0.69 ± 0.14, 0.72 ± 0.24 and 0.94 ± 0.33, respectively (P < 0.01 in anova test). Post hoc tests show that the severe OSA group had significantly higher mean CIMT than the control and mild-moderate OSA groups (P < 0.01). With the cut-off as 1 mm, the increased risks of cardiovascular disease (CVD) for mild-moderate and severe OSA were 11% and 39%, respectively, while no patient in the healthy control group was at risk of CVD. Multivariate linear regression could not prove that OSA itself was an independent factors for increased CIMT (mild-moderate OSA β: 0, [-0.12, 0.13]; severe OSA β: 0.08, [-0.06, 0.22], both P > 0.05) after adjusting age, hypertension and body mass index.

CONCLUSION

Automated measurement of the CIMT can be a useful tool for CVD risk assessment in patients with OSA. Severity of OSA may be an intermediate factor between multiple co-morbidities and carotid atherosclerotic change.