The research on vascular endothelial dilatation function in elderly patients with obstructive sleep apnea hypopnea syndrome / 中华老年医学杂志

ABSTRACT

Objective To evaluate the vascular endothelial dilatation function in elderly patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods Thirty elderly patients with moderate to severe OSAHS and twenty-eight control subjects were studied. Their blood concentration of nitric oxide (NO) were quantified. Brachial artery diameter was measured with Doppler ultrasound under baseline conditions, during reactive hyperemia (an endothelium-dependent dilatation) and after sublingual administration of nitroglycerin ( an endothelium-independent vasodilator). The dilative rate of brachial artery in different conditions was calculated to evaluate the endothelial function. Subjects with OSAHS were treated by nasal continuous positive airway pressure (nCPAP) for 4 weeks, and the level of NO in plasma and vascular endothelial function were measured. Results Compared with control group, there was a significant decrease of NO level in elderly patients with moderate to severe OSAHS [(50. 35±8.65)μmol/L vs. (57.31±9.31)μmol/L, t=2.95,P=0.005], and the level of NO in plasma was increased after nCPAP treatment for 4 weeks [(55.77±8.87)μmol/L vs. (50.35± 8.65)μmol/L,t=2.40,P=0.023. The elderly patients with moderate to severe OSAHS had lower endothelium-dependent flow-mediated dilation (FMD) compared with control subjects [(9.78± 4.82)%vs. (13.21±5.81)%,t=2.45, P=0.017], and there was no significant difference in endothelium-independent nitroglycerin ( NTG)-induced dilation [( 16.87±6.15)% vs. (14.74 ± 5.82)%,t=1.36,P=0.18]. After nCPAP treatment for 4 weeks, the patients with moderate to severe OSAHS had significant increase in FMD[(14.33±6.13)% vs. (9.78±4.82)%, t=3.20,P= 0.002], whereas there was no significant change in NTG-induced dilation [(14.74±5.82)% vs. (15.15±4.21)%, t=0.31,P=0.76]. Conclusions The elderly patients with moderate to severe OSAHS have abnormal vascular endothelial function, and nCPAP treatment can reverse the dysfunction effectively, which may be associated with the reversal of intermittent hypoxia.