Sex differences of continuous positive airway pressure treatment on flow-mediated dilation in patients with obstructive sleep apnea syndrome

Abstract

IntroductionThere is growing research evidence suggesting the presence of endothelial dysfunction and systemic inflammation in patients with obstructive sleep apnea syndrome (OSAS). Continuous positive airway pressure (CPAP) is the most effective method for treating OSAS; nonetheless, the effects of CPAP on the aforementioned pathophysiologic pathways as well as on the systemic disease that result or coexist with the OSAS remain elusive.AimTo assess the effect of 3-month CPAP therapy on endothelial-dependent dilation, plasma levels of inflammatory markers, blood pressure (BP), and glucose control on male and female patients with OSAS.MethodsOur study group consisted of 40 (24 males and 16 females) patients with no prior history of cardiovascular disease, with an apnea–hypopnea index ≥15, who were assigned to receive CPAP treatment. Measurements of flow-mediated dilation (FMD), 24-hour ambulatory BP, and blood analysis were performed at baseline and 3 months after CPAP therapy.ResultsBaseline FMD values were negatively correlated with the apnea–hypopnea index (r=−0.55, P=0.001). After 3 months of CPAP, there was an increase in the FMD values (5.40%±2.91% vs 3.13%±3.15%, P<0.05) and a significant reduction in the patients’ 24-hour systolic BP (122.82±11.88 mmHg vs 130.24±16.75 mmHg, P<0.05), diastolic BP (75.44±9.14 mmHg vs 79.68±11.09 mmHg, P<0.05), and pulse pressure (47.38±9.77 mmHg vs 52.72±11.38 mmHg, P<0.05); daytime systolic BP (125.76±12.69 mmHg vs 132.55±17.00 mmHg, P<0.05) and diastolic BP (77.88±10.39 mmHg vs 82.25±11.01 mmHg, P<0.05); nighttime systolic BP (118.17±13.16 mmHg vs 126.22±17.42 mmHg, P<0.05) and pulse pressure (46.61±10.76 mmHg vs 52.66±11.86 mmHg, P<0.05); and C-reactive protein and HbA1c levels (0.40 [0.40–0.70] mg/L vs 0.60 [0.40–0.84] mg/L and 5.45%±0.70% vs 5.95%±1.08%, respectively; P<0.05). When divided by sex, only male patients produced similar statistically significant results, while female patients failed to show such associations.ConclusionOur results suggest that CPAP therapy improves the endothelial function, the BP, and the glucose control in male patients with OSAS. Further research is warranted in order to verify these results and to further elucidate the impact of CPAP on the cardiovascular risk of male and female patients with OSAS.

Obstructive sleep apnoea syndrome and endothelial function: potential impact of different treatment strategies—meta-analysis of prospective studies

“…Finally, 18 studies could be included in the quantitative meta-analysis (Fig. 1) [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Study design and baseline clinical characteristics are summarized in Table 1.…”

Sex differences in renal hemodynamics and renin-angiotensin system activity post-CPAP therapy in humans with obstructive sleep apnea

“…Conversely, moderatesevere OSA was associated with retinal arteriolar narrowing and venular widening in men but not women (37). CPAP for 3 mo significantly improved endothelial function, BP, and glycemic control in men but not women (33). Previous studies specifically evaluating CPAP and the RAS in OSA have excluded female participants (39, 51, 57) or included few women (42), did not examine their participants; hypoxemia profiles, and, most importantly, did not control for kidney function, Na ϩ intake, or other factors known to affect the RAS.…”

“…We have previously demonstrated that OSA is associated with glomerular hyperfiltration that is improved by CPAP through renal renin-angiotensin system (RAS) downregulation (44). Renal hemodynamic responses to angiotensin II (ANG II) vasoconstrictor challenge (40) and RAS blockade (41) differ by sex in healthy humans, and the vascular effects of OSA also differ by sex (33,37). However, whether the beneficial effects of CPAP on renal hemodynamics and RAS activity in patients with OSA differ by sex is unknown.…”

Endothelial Function and Arterial Stiffness Should Be Measured to Comprehensively Assess Obstructive Sleep Apnea in Clinical Practice

“…It is unknown whether different subtypes of OSA have different vascular functions and stiffness. Gender can also influence endothelial function (22). Although some studies have applied PAT to explore the association between endothelial function and OSA, few studies have been performed in Chinese patients with OSA without severe comorbidities.…”