Objective: Although obstructive sleep apnea syndrome (OSAS) is accompanied by increased atherosclerotic cardiovascular disease burden, its relation with arterial stiffness is not yet well determined. We investigated whether essential hypertensive subjects with OSAS are characterized by increased arterial stiffness.

Methods: Our study population consisted of 46 consecutive subjects with newly diagnosed untreated stage I–II essential hypertension suffering from OSAS (35 men, aged 49±8 years) and 53 hypertensive subjects without OSAS, matched for age, sex, and smoking status. All subjects underwent polysomnography, echocardiography and aortic stiffness evaluation by means of carotid-femoral pulse wave velocity (c-f PWV) measurements.

Results: Hypertensives with OSAS [apnea hypopnea index (AHI) ⩾5] compared to hypertensives without OSAS (AHI < 5), demonstrated increased levels of body mass index (31.4±4 vs 29.3±4 kg/m², p = 0.015), office systolic/diastolic blood pressure (BP) (151/99vs145/94 mmHg respectively, p < 0.05, for both cases) and relative wall thickness (0.46±0.06 vs 0.42±0.07, p = 0.010). Hypertensives with OSAS compared to those without OSAS had significantly increased c-f PWV by 9% (8.56±0.49 vs 7.85±0.93 m/s, p = 0.001) and this difference remained significant even after adjustment for confounders (p = 0.04). In the total study population, c-f PWV was correlated with age (r = 0.35, p = 0.015), office systolic BP (r = 0.30, p = 0.007), relative wall thickness (r = 0.30, p = 0.03), logAHI (r = 0.389, p = 0.0001) and minimum oxygen saturation (minSatO₂) (r = −0.418, p = 0.0001).

Conclusions: OSAS has a significant incremental effect on aortic stiffening in the setting of middle-aged essential hypertensive subjects. This finding suggests that the presence of OSAS in a hypertensive patient accelerates vascular damage, increasing cardiovascular risk.