老年阻塞性睡眠呼吸暂停低通气综合征患者血管内皮舒张功能的变化

目的 评价老年阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者血管内皮舒张功能的变化.方法 老年中重度OSAHS患者30例及对照组28例,分别测定血浆一氧化氮(NO)含量;用高分辨率超声检测基础状态、反应性充血时(内皮依赖性血管扩张)及含服硝酸甘油后(非内皮依赖性血管扩张)的肱动脉内径,计算不同状态下肱动脉的扩张率以评估血管内皮功能.老年中重度OSAHS患者经过4周经鼻持续气道内正压通气(nCPAP)治疗后重复多导睡眠监测、血浆NO含量和血管内皮功能测定.结果 老年中重度OSAHS组的血浆NO含量[(50.35±8.65)gmol/Li较对照组[(57.31±9.31)μmol/Li降低(t=2.95,P=0.005),接受4周的nCPAP治疗后血浆NO含量[(55.77±8.87)μmol/Li有明显升高(t=2.40,P=0.02).老年中重度OSAHS组反应性充血时肱动脉内径扩张率[(9.78±4.82)%较对照组[(13.21±5.81)%]明显减低(t=2.45,P=0.017);而对照组和老年中重度OSAHS组由硝酸甘油介导的血管扩张率分别为(16.87±6.15)%和(14.74±5.82)%(t=1.36,P=0.18).老年中重度OSAHS组接受4周nCPAP治疗后反应性充血时肱动脉内径扩张率为(14.33±6.13)%,较治疗前明显改善(t=3.20,P=0.002),而硝酸甘油介导的血管扩张率为(15.15±4.21)%,较治疗前无明显变化(t=0.31,P=0.76).结论 老年中重度OSAHS组患者存在血管内皮功能异常,nCPAP治疗能有效修复这些损害,其机制可能与纠正间断缺氧有关.

The research on vascular endothelial dilatation function in elderly patients with obstructive sleep apnea hypopnea syndrome

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.