Obstructive sleep apnea and silent cerebral infarction in hypertensive individuals

Obstructive sleep apnea syndrome is very prevalent in hypertensive subjects. Moreover, obstructive sleep apnea syndrome activates multiple processes that might be associated with silent cerebral infarct independently of established risk factors. Our aim is to estimate the frequency of obstructive sleep apnea syndrome in hypertensive patients with and without silent cerebral infarct, and to determine whether obstructive sleep apnea syndrome is an independent risk factor of silent cerebral infarct and/or lacunar silent cerebral infarct in patients with hypertension. In this matched cross-sectional study performed in hypertensive subjects, each patient with silent cerebral infarct detected by magnetic resonance imaging was matched with two patients without silent cerebral infarct. Polysomnographic studies were performed, and the apnea-hypopnea index was calculated. Severe obstructive sleep apnea syndrome was considered in those with apnea-hypopnea index >30. One-hundred and eighty-three patients, 61 with silent cerebral infarct and 122 without silent cerebral infarct, were evaluated. The mean age was 64.1 +/- 4.5 years, and 72.1% were men. The frequency of severe obstructive sleep apnea syndrome was 44.3% in patients with silent cerebral infarct and 38.5% in the control group. An adjusted conditional logistic regression model did not show a significant increased risk of silent cerebral infarct in patients with severe obstructive sleep apnea syndrome (odds ratio 1.362; 95% confidence interval: 0.659-2.813; P=0.404). Forty-three patients (70.5%) of the silent cerebral infarct were lacunar. The presence of severe obstructive sleep apnea syndrome was significantly higher in lacunar silent cerebral infarct when compared with patients without lacunar infarcts (55.8% versus 35.7%, P=0.019), being independently associated on an adjusted logistic regression model (odds ratio 2.177; 95% confidence interval: 1.058-4.479; P=0.035). In conclusion, severe obstructive sleep apnea syndrome is highly prevalent among hypertensive subjects, and is independently associated with lacunar silent cerebral infarct.