Assessment Of Cerebrovascular Reactivity Of Obstructive Sleep Apnea Hypopnea Syndrome With Transcranial Doppler Ultrasonography

Objective To investigate the value of transcranial Doppler ultrasonography(TCD)for assessing the cerebrovascular reactivity (CVR)in obstructive sleep apneahypopnea syndrome (OSAHS)patients.Methods Sixty OSAHS outpatients and inpatients admitted to our neurology department from August 2015to December 2016served as an OSAHS group,then further divided into mild group(n=15),moderate group(n=27)and severe group(n=18)according to apneahypopnea index(AHI).Meanwhile,20healthy individuals served as a control group.They underwent TCD on admission to detect their CVR,including the average velocity of cerebral artery blood flow(Vm)during calm breathing and after breath holding.The breath holding index(BHI) was calculed.The relationship between BHI and CVR was analized by pearson linear correlation analysis. Results There was no statistically significant difference in Vm during calm breathing between the OSAHS and control groups(73.64±9.87cm/s vs 72.79±8.68cm/s,P＞0.05).Both of Vm after breath holding and BHI of the OSAHS group were lower than those of the control group(88.63±6.65cm/s vs 93.26±7.12cm/s,0.71±0.16 vs 0.93±0.37,P＜0.01).Both of Vm after breath holding and BHI of the mild group were the highest,while the severe group had the lowest values and the moderate group was in between(P＜0.05).No significant correlation was found between AHI and Vm during calm breathing(r=0.197,P=0.052),while AHI was negatively correlated with Vm after breath holding and BHI(r=-0.557,P =0.011;r=-0.605,P=0.000).Conclusion TCD can detect CVR changes in OSAHS patients,whose Vm after breath holding and BHI decrease significantly.The more severe the OSAHS is,the lower the CVR is.