Arterial Stiffness Associated with Sympathetic Hyperactivity in Obese Individuals with Moderate to Severe Obstructive Sleep Apnea.

INTRODUCTION

Obstructive Sleep Apnea (OSA) is a chronic disorder associated with several risk factors, and increased Body Mass Index (BMI) and waist circumference are correlated with it is severity.

AIM: To evaluate vascular function, central hemodynamics, and autonomic modulation in obese individuals with moderate and severe OSA.

METHODS

Individuals of both sexes, aged 40-70 years and BMI ≥ 30 and < 40 kg/m2, were submitted to assessment of heart rate variability, endothelial function by flow-mediated dilatation, central parameters by oscillometry and carotid ultrasound. The sleep study was performed through a portable home sleep test device (WatchPAT).

RESULTS

Patients (n = 76) were divided according to Apnea-Hypopnea Index (AHI): absent-mild group (AHI < 15 events/h, n = 30) and Moderate-Severe (MS) group (AHI ≥ 15 events/h, n = 46). The Low/High Frequency (LF/HF) ratio (0.81  ±  0.48 vs 1.39  ±  1.08 ms2, p = 0.035), Pulse Wave Velocity (PWV; 6.9  ±  0.7 vs 7.7  ±  1.6m/s, p = 0.004), vascular age (48  ±  6 vs 53  ±  9 years, p = 0.05) and mean intima-media thickness (0.59  ±  0.08 vs 0.66  ±  0.13 mm, p = 0.011) were significantly higher in the MS group. AHI was significantly correlated with PWV (r = 0.26, p = 0.024) and LF/HF ratio (r = 0.40, p < 0.001). Only in the MS group, PWV was significantly correlated with SD2/SD1 ratio (r = 0.611, p ≤ 0.001), and flow-mediated dilation with central systolic blood pressure (r = 0.364, p = 0.018), even after adjustment for age and sex.

CONCLUSION

In this sample of obese individuals, moderate to severe OSA was associated with sympathetic hyperactivity and evidence of accelerated vascular aging with arterial stiffness and subclinical atherosclerosis.