Increased Aortic Root Size is Associated with Nocturnal Hypoxia and Diastolic Blood Pressure in Obstructive Sleep Apnea

Study Objectives: Obstructive sleep apnea (OSA) is known as a major cardiovascular risk factor, and high prevalence of OSA has been reported in patients with thoracic aortic dissection. The aim of our study was to assess the relationship between OSA, its vascular consequences, and aortic root size. Design/Patients: 156 newly diagnosed apneic patients free of cardiovascular disease and medication were included. Patients underwent cardiac ultrasound for measuring aortic root diameter, polysomnography, office and 24-h ambulatory blood pressure (BP) measurements, baroreflex sensitivity (BRS), and arterial stiffness evaluation by carotid-to-femoral pulse wave velocity (PWV). Measurements and Results: In univariate analysis, greater aortic root size was associated with older age (P = 0.03) and severity of OSA as expressed by mean nocturnal oxygen saturation (SpO(2)) (P = 0.015). Moreover, greater aortic root size was associated with higher diastolic BP, measured both clinically (P = 0.0005) or by 24-h ambulatory BP monitoring (P = 0.02), and PWV (P = 0.03). Mean nocturnal SpO(2) was correlated with BRS (P = 0.0008), thus potentially influencing BP values and arterial stiffness. In multivariate stepwise regression analysis, diastolic BP was the only significant factor for aortic root size (P = 0.0003). Conclusions: In OSA patients, nocturnal hypoxemia decreased BRS and increased diastolic BP, which was the main factor influencing aortic root size.