Big Endothelin-1 and Nitric Oxide in Hypertensive Elderly Patients with and without Obstructive Sleep Apnea-Hypopnea Syndrome

Background

The role of oxidative stress in hypertensive elderly patients withobstructive sleep apnea-hypopnea syndrome (OSAHS) is unknown.

Objective

The purpose was to evaluate the levels of big endothelin-1 (Big ET-1) andnitric oxide (NO) in elderly hypertensive patients with and without moderateto severe OSAHS.

Methods

Volunteers were hospitalized for 24 h. We obtained the following data: bodymass index (BMI); 24-ambulatory blood pressure monitoring; and currentmedication. Arterial blood was collected at 7pm and 7am for determiningplasma NO and Big ET-1 levels. Pulse oximetry was performed during sleep.Pearson''s or Spearman''s correlation and univariate analysis of variance wereused for statistical analysis.

Results

We studied 25 subjects with OSAHS (group 1) and 12 without OSAHS (group 2)aged 67.0 ± 6.5 years and 67.8 ± 6.8 years, respectively. No significantdifferences were observed between the groups in BMI; number of hours ofsleep; 24-h systolic and diastolic BPs; awake BP, sleep BP and medicationsto control BP between groups. No differences were detected in plasma BigET-1 and NO levels at 19:00 h, but plasma Big ET-1 levels at 7:00 h werehigher in group 1 (p = 0.03). In group 1, a negative correlation was alsoobserved between the mean arterial oxyhemoglobin saturation level, 24-hsystolic BP (p = 0.03, r = −0.44), and Big ET-1 (p = 0.04, r = −0.41).

Conclusions

On comparing elderly hypertensive patients with and without OSAHS havingsimilar BP and BMI, we observed higher Big ET-1 levels After sleep in theOSAHS group. NO levels did not differ between the hypertensive patients withor without OSAHS.