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.