A study on the association between the severity of newly diagnosed obstructive sleep apnea and subclinical carotid atherosclerosis in patients without overt cardiovascular disease

Background: Obstructive Sleep Apnea (OSA) has been associated with both subclinical and accelerated atherosclerosis; however, it 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. Objective: To prospectively examine whether patients with newly diagnosed moderate/severe OSA carry a higher burden of carotid atherosclerosis as compared to healthy, well matched for all standard Framingham risk factors patients. Methods: A total of 40 subjects without clinically diagnosed cardiovascular disease 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 intima media thickness (cIMT) and presence of atheromatic plaques on both carotid arteries. Measurement was performed using B-mode ultrasonogram. Results: Moderate to severe OSA was diagnosed in 21 subjects. While patients with OSA had a higher BMI compared to healthy subjects, both groups were well matched and of similar cardiovascular risk profile. 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). Conclusion: 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.