Association between the severity of newly diagnosed obstructive sleep apnea and subclinical carotid atherosclerosis in patients without overt cardiovascular disease

OBJECTIVE: Obstructive Sleep Apnea (OSA) has been associated with both subclinical and accelerated atherosclerosis; however, it still remains unknown whether this association is unique or is mediated by the higher burden of co-existing cardio-metabolic disorders frequently seen in patients with OSA.

PATIENTS AND METHODS: A total of 40 subjects without clinically diagnosed cardiovascular disease (CVD) referred for polysomnography test were included in the study. Subjects with apnea/hypopnea index (AHI > 15/h) were classified as moderate/severe OSA. Subclinical changes in carotid atherosclerosis were assessed using mean carotid intima-media thickness (cIMT) and presence of atheromatic plaques on both carotid arteries. The measurement was performed using B-mode ultrasonogram. Framingham risk score was used in the approximation of cardiovascular risk.

RESULTS: The mean age of our cohort was 56.8 years, 70% (n = 28) of whom were males. Moderate/severe OSA was diagnosed in 21 subjects. Both groups were well matched in terms of clinical and demographic characteristics, and cardiovascular risk profile, as shown in their respective Framingham risk scores (10.4 ± 6.6 vs. 11.8 ± 8.8, p = NS). Patients with moderate/severe OSA had a higher mean AHI, 3% oxygen desaturation index, and lower minimum nocturnal oxygen saturation than controls. No significant differences were detected in terms of C-reactive protein levels. The two groups had similar cIMT (0.66 ± 0.17 vs. 0.75 ± 0.20 p = 0.33) and presence of atheromatic plaque (50% vs. 45%, p = 1.00).

CONCLUSIONS: Our study suggests that among patients with similar cardiovascular risk profile and free of overt CVD, the severity of newly diagnosed OSA was not correlated with increased inflammation or subclinical carotid atherosclerosis.