[Influence of sleep apnea on nocturnal blood pressure]

In the present study, we subjected 65 patients to overnight monitoring and continuous nocturnal blood pressure measurement in order to assess the influence of sleep apnea on the circulatory system. Thirty-one patients were compared before and after surgery. The severity of sleep apnea was classified by Apnea Hypopnea Index (AHI), the duration of exposure to low-level oxygen (calculated as the desaturation time: DT), and increment of blood pressure. Before surgery, a significant correlation was noted between the DT and blood pressure changes. Therefore, this index was considered useful for assessing the influence of sleep apnea on nocturnal blood pressure. After surgery, improvement of AHI was greater than 50% in 19/31 patients (61.3%), and this result was almost the same as described in the literature. The improvements in DT and BP change were greater than 50% in 21/31 (67.7%) and 14/31 (45.2%), respectively. With regard to severity before surgery, AHI was > or = 50 and DT was > or = 40% in 10 and 18 patients, respectively. Nineteen patients had BP changes > or = 40 mmHg. After surgery, 1,5, and 2, patients, respectively, still showed these values. Thus, a beneficial effect of surgery was demonstrated.