The Association of Nocturnal Hypoxemia with Arterial Stiffness and Endothelial Dysfunction in Male Patients with Obstructive Sleep Apnea Syndrome

Abstract

Background: Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular complications, and atherosclerosis is considered to mediate this association. Arterial stiffness and endothelial dysfunction are widely accepted as early markers of atherosclerosis. Objectives: The purpose of this study was to investigate the influence of sleep apnea on arterial stiffness and endothelial dysfunction. Methods: We enrolled 83 OSAS patients including 39 with mild to moderate degree (apnea hypopnea index, AHI ≧5, AHI <30) and 44 with severe degree sleep apnea (AHI ≧30) and 29 normal control subjects (AHI <5). After finishing polysomnography, carotid-femoral pulse wave velocity (cfPWV) and flow-mediated dilation (FMD) were measured using noninvasive devices. Results: In patients with severe degree of OSAS, cfPWV was significantly higher than mild to moderate degree of OSAS or normal control subjects. Also, the severe OSAS group showed lower FMD than the normal control group (all p < 0.01). The cfPWV was significantly correlated with FMD (r = –0.26, p < 0.01). Age (β = 0.33, p < 0.01) and percentage of time below 90% O₂ saturation (β = 0.34, p < 0.01) were the significant variables to determine cfPWV (adjusted R² = 21%, p < 0.01) in multivariate analysis, and the lowest O₂ saturation was a significant determinant for FMD (β = 0.25, adjusted R² = 6%, p < 0.01). Conclusions: Nocturnal hypoxemia may alter arterial elasticity and endothelial function in OSAS patients, and those impairments could increase the risk of cardiovascular complications.

Increased arterial stiffness in obstructive sleep apnea: a systematic review

“…46 It was found that, whereas both types of OSA patients showed significantly higher arterial stiffness as compared to healthy controls, OSA patients with masked hypertension had the highest arterial stiffness. Chung et al 47 compared cfPWV in patients with mild to moderate OSA, severe OSA and control subjects. They found cfPWV to be significantly higher in patients with severe OSA as compared to both mild to moderate OSA and normal controls.…”

“…Out of the seven studies investigating the association between severity of OSA and arterial stiffness, 45,47,48,51,52,60,62 six provided full support for the association 45,47,51,52,60,62 and one provided mixed results. 48 More specifically, the study by Protogerou et al 48 did not find a direct association between OSA severity categories (moderate, severe and very severe) and arterial stiffness.…”

“…The methods of assessing arterial stiffness also differed between studies; however, it is encouraging that eight studies used cfPWV, AIx or both as parameters of arterial stiffness. [42][43][44][45]47,48,53,54 Furthermore, limiting our search to English language publications may have led to an omission of potentially relevant studies. Owing to methodological constraints, a meta-analysis of studies aiming to also quantify the overall magnitude of the effect of OSA on arterial stiffness could not be conducted.…”

Response to Impact of Obstructive Sleep Apnea on Cardiovascular Outcomes in Patients Treated With Percutaneous Coronary Intervention: Rationale and Design of the Sleep and Stent Study

“…In another recent study, 5 OSA syndrome was shown to increase Rho-associated protein kinase activity and to be a major determinant of endothelial dysfunction. Chung et al 6 also showed that nocturnal hypoxemia may alter arterial elasticity and endothelial function in patients with OSA syndrome.…”

Association between sleep‐disordered breathing and arterial stiffness in heart failure patients with reduced or preserved ejection fraction

“…Several studies have revealed higher PWV in obstructive sleep apnoea (OSA) patients than in controls and reported nocturnal oxygen desaturation to be associated with high PWV 19, 20…”