Correlation between severity of obstructive sleep apnea and prevalence of silent cerebrovascular lesions

We investigated the prevalence of silent cerebrovascular lesions in patients with obstructive sleep apnea (OSA) and the correlation between OSA severity and prevalence of silent cerebrovascular lesions in Japanese patients.

Study subjects were 192 polysomnography (PSG)-confirmed patients who visited the sleep disorders clinic in our university hospital. None had a history of cerebrovascular disease (CVD). We performed a cross-sectional study on OSA severity and the prevalence of silent cerebrovascular lesions detected by brain MRI analysis.

The control (AHI < 5/h) group included 19 subjects with a mean AHI of 1.7 +/- 1.6/h, the mild OSAS (AHI 5 to < 15/h) group included 25 patients with a mean AHI of 9.5 +/- 3.7/h, the moderate OSAS (AHI 15 to < 30/h) group included 35 patients with a mean AHI of 22.0 +/- 7.0/h while the severe OSAS (AHI > or = 30/h) group included 113 patients with a mean AHI of 59.9 +/- 20.5/h. A larger percentage of patients with severe OSAS had a higher BMI and hyperglycemia than those with mild or moderate OSAS and control subjects (p < 0.05). Silent lacunar infarction was identified in 4 (21.1%) control subjects, 3 (12.0%) patients with mild OSA, 17 (48.6%) with moderate OSA and 61 (54.0%) with severe OSA. Among control subjects and the mild, moderate, and severe OSA groups, 4 (21.1%), 5 (20.0%), 19 (54.3%) and 61(54.0%), respectively, had periventricular hyperintensity (PVH); most PVH was mild to moderate.

Results indicate that patients with moderate to severe (AHI > or = 15/h) OSA have a higher prevalence of silent cerebrovascular lesion than those with less severe OSA.