Arterial stiffness and heart rate variability analysis in patients with mild–moderate obstructive sleep apnoea, with and without excessive daytime sleepiness

Valeria Bisogni, Martino F. Pengo, Panagis Drakatos, Brian Kent, Joerg Steier, Gian Paolo Rossi

Abstract

Background: Patients with severe obstructive sleep apnoea syndrome (OSAS) show higher risk of cardiovascular disease (CV) and exhibit an increased arterial stiffness and a deregulation of autonomic nervous system (ANS) activity. Data are lacking in patients with mild-moderate OSAS. The study aimed to analyze heart rate variability (HRV) and arterial stiffness in patients with mild–moderate OSAS, with and without symptoms of excessive daytime sleepiness (EDS).
Methods: Fifty-six male patients with mild–moderate OSAS [apnoea/hypopnea index (AHI) between 5 and 30 events/hour], without any CV risk factor, underwent full polysomnography (NPSG). Patients were divided into two groups according to the Epworth Sleepiness Scale (ESS), a subjective assessment of daytime sleepiness. During the first and the last 5 minutes of NPSG, in the wake stage, and overnight we have analysed arterial stiffness index (SIDVP), derived from digital plethysmogram, and heart rate variability.
Results: The two groups were matched for age, body mass index (BMI) and AHI, did not show differences in terms of arterial stiffness. Patients with an ESS >10 had similar values of SIDVP compared with patients without EDS. In terms of HRV we have found a significant difference only in low frequency (LF) power at the end of the NPSG study (LF power 14,601±7,495 vs. 21,031±14,257 ms2, P<0.05), with no differences in the other HRV parameters.
Conclusions: Patients with mild-moderate OSAS, with or without EDS, exhibit similar arterial stiffness and HRV and therefore might have a similar CV risk.