Study On Correlation Between Cerebrovascular Reactivity And Oscular Blood Flow In Normal People In Qinghai

Objective:To explore the correlation between cerebrovascular reactivity and ocular blood flow.Methods:From October 2018 to March 2019,80 healthy normal people(21-50 years old)were selected as the research objects at the physical examination center of Qinghai Provincial People's Hospital.The German DWL Transcranial Multi-Dop X equipment was used to detect the mean blood flow velocity of the middle cerebral artery and the end-expiratory CO2 partial pressure in the monitoring mode.Cerebrovascular reactivity(CVR)to hypocapnia and hypercapnia were calculated by hyperventilation test and CO2 inhalation test.Blood flow parameters of ophthalmic artery(OA)were measured in the conventional mode,including mean blood flow velocity(MFV),pulsatility index(PI)and resistance index(RI)of ophthalmic artery.The 3D OCT-2000 produced by Topcon Company was used to take fundus color photos,and we measured the retinal artery and vein diameter by using the computer software program Image J and calculated their ratio.Statistical analysis:(1)To analyze whether there is a difference between CVR to hypocapnia and hypercapnia.(2)CVR of different ages and genders were compared respectively.(3)The ophthalmic artery blood flow parameters and retinal vessel diameter of different ages and genders were compared respectively.(4)To analyze the correlation between CVR and ophthalmic artery blood flow parameters and retinal vessel diameter.Results:(1)The CVR to hypocapnia is significantly lower than to hypercapnia in normal people(t=-23.081,P<0.05).(2)Both CVR to hypocapnia and hypercapnia decreased gradually with age,and the difference was statistically significant(F=14.541,P<0.05;F=16.377,P<0.05).There was no significant difference in both CVR to hypocapnia and hypercapnia between men and women(P>0.05).(3)The PI and RI of ophthalmic artery increased gradually with age,the difference was statistically significant(F=12.772,P<0.05;F=19.314,P<0.05).There was no significant difference in MFV of ophthalmic artery among different ages(P>0.05).There was no significant difference in MFV,PI,RI of ophthalmic artery between men and women(P>0.05).(4)There was no significant difference in retinal artery diameter(RAE),retinal vein diameter(RVE)and their ratio(AVR)among different ages(P>0.05).There was no significant difference in RAE,RVE and AVR between men and women(P>0.05).(5)There was a negative correlation between the CVR to hypocapnia and PI,RI of ophthalmic artery(r=-0.806,P<0.05;r=-0.779,P<0.05).There was still a negative correlation(r=-0.738,P<0.05;r=-0.686,P<0.05)between the CVR to hypocapnia and PI,RI of ophthalmic artery after controlling the influence of different ages.There was a negative correlation(r=-0.783,P<0.05;r=-0.766,P<0.05)between the CVR to hypercapnia and PI,RI of ophthalmic artery.There was still a negative correlation(r=-0.704,P<0.05;r=-0.660,P<0.05)between the CVR to hypercapnia and PI,RI of ophthalmic artery after controlling the influence of different ages.There was no significant correlation between CVR and MFV of ophthalmic artery(P>0.05).(6)There was a positive correlation between the CVR to hypercapnia and AVR(r=0.284,P<0.05),but no significant correlation with RAE and RVE(P>0.05).There was no significant correlation between the CVR to hypocapnia and RAE,RVE and AVR(P>0.05).Conclusion :(1)The normal people's cerebrovascular reactivity to hypocapnia is weaker than cerebrovascular reactivity to hypercapnia in Qinghai.(2)Age is a risk factor of cerebrovascular reactivity damage and ophthalmic arteriosclerosis in normal people in Qinghai.(3)The normal people's cerebrovascular reactivity is correlated with the ocular blood flow in Qinghai,among which pulsatility index and resistance index of the ophthalmic artery are highly correlated with cerebrovascular reactivity.