Quantitative Evaluation Of Collateral Circulation And Cerebral Hemodynamics Changes In Patients With Severe Stenotic Lesions Of Internal Carotid Artery

The paper involved two aspects:(1)Feasibility study of semi-quantitative evalution of cerebral collateral circulation with unilateral internal carotid artery severe stenotic lesions;(2)To investigate the cerebral hemodynamic changes after unilateral carotid endarterectomy(CEA)for bilateral internal carotid artery severe stenotic lesions.PartI:Feasibility study of semi-quantitative evalution of cerebralcollateral circulation with unilateral internal carotid artery severestenotic lesionsObjectiveTo investigate the feasibility of using transcranial Doppler(TCD)to semi-quantify cerebral collateral circulation in patients with unilateral internal carotid artery(ICA)severe stenotic lesions.Methods1.Case data:From august 2015 to October 2017,145 patients with unilateral ICA severe stenotic lesions comfirmed by multi-modal imaging in stroke center of the First Affiliated Hospital of Soochow University were included retrospectively.The cerebral collateral circulation was evaluated by TCD and digital subtraction angiography(DSA),and we conducted consistency test of their results.There were 128 patients whose two results were consistent,and we used TCD to semi-quantify cerebral collateral circulation of these patients.We set that the opening of anterior communicating artery(ACoA),posterior communicating artery(PCoA)and ophthalmic artery(OA)were 3 points,2 points and 1 point,respectively.2.Inclusion criteria:(1)unilateral ICA severe stenosis(≥70%)or occlusion;(2)consistent imaging findings and complete data.Exclusion criteria:(1)TCD examination of poor temporal window;(2)combined with other large intracranial or extracranial vessels severe stenotic lesions;(3)previous cerebral infarction.3.Research group:128 patients were devided into symptomatic group(90cases)and asymptomatic group(38cases).We used the receiver operating characteristic curve(ROC)to analyse two groups of their collateral circulation scores and to determine the optimal cut-off value for poor group(86 cases)and good group(42cases)of collateral circulation.The parameters of TCD and computed tomography perfusion(CTP)were compared between two groups.TCD collateral circulation scores and the Alberta Stroke Programme Early CT Scores(ASPECTS)were performed correlation analysis.4.Statistical analysis:Kappa value was used to calculate the consistency between TCD and DSA who were used to evaluate cerebral collateral circulation.The rank datawere expressed by example(%)and the rank sum test was used for inter-group comparison;the measurement data were expressed by(x±s)and the inter-group comparison was expressed by independent sample t-test.The ROC curve of TCD collateral circulation score was analyzed,and the best diagnostic threshold,sensitivity and specificity were determined according to the maximum point of Youden index.Spearman rank correlation test was used to analyze the correlation between TCD collateral circulation score and ASPECTS.Results1.Consistency test:The consistencies of ACoA,PCoA and OA which were assessed by TCD and DSA were all excellent(Kappa value=0.879,0.787,0.770,P<0.01).2.ROC curve analysis:The differences of collateral circulation scores between symptomatic group and asymptomatic group had statistical significance(P<0.01).The ROC curve showed that the optimal cut-off value of collateral circulation scores was 3.5 points,and the sensitivity was 73.7%,and the specificity was 84.4%.3.TCD parameters:The mean blood flow velocity(Vm)of ipsilateral middle cerebral artery(MCA)in poor collateral circulation group was significantly lower than that in good collateral circulation group(P<0.01),and the pulsatility index(PI)in poor collateral circulation group was lower than that in good collateral circulation group,but the differences had no statistical significance(P>0.05).4.CTP parameters:The cerebral blood flow(CBF)and cerebral blood volume(CBV)of ipsilateral basal ganglia area and temporal lobe in poor collateral circulation group were significantly lower than those in good collateral circulation group(P<0.01),and the mean transit time(MTT)and time to peak(TTP)in poor collateral circulation group were significantly longer than those in good collateral circulation group(P<0.01).5.Correlation analysis:The TCD collateral circulation score was highly positivity correlated with ASPECTS(r=0.767,P<0.01).ConclusionTCD can semi-quantify the collateral circulation of unilateral ICA with severe stenotic lesions,and it is of guiding significance for clinical diagnoses and treatments.Part II:To investigate the cerebral hemodynamic changes after unilateralCEA for bilateral internal carotid artery severe stenotic lesionsObjiectiveTo investigate the changes of cerebral hemodynamic in patients with severe stenotic lesions of bilateral ICA after unilateral carotid endarterectomy(CEA).Methods1.Case data:A retrospective study of 41 consecutive patients in the department of neurosurgery,the First Affiliated Hospital of Soochow University from February 2012 to June 2018,who were confirmed by multi-modal images with severe stenotic lesions of bilateral ICA and underwent unilateral CEA(the operated side was severe stenosis and the rate of stenosis ≥70%).The opening of ACoA and PCoA were evaluated by computed tomography angiography(CTA)before and after CEA.2.Inclusion criteria:(1)severe stenotic lesions of bilateral ICA and underwent unilateral CEA;(2)underwent the examination within 24 hours before operation and 5 days after operation(examination interval<24 hours).Exclusion criteria:(1)combined with other large intracranial or extracranial vessels severe stenotic lesions;(2)poor temporal window by transcranial Doppler(TCD);(3)incomplete imaging data or controversial diagnostic results.3.Research group:According to the postoperative CTA,whether ACoA was opened or not,41 patients were devided into ACoA open group(15 cases)and ACoA non-open group(26 cases).We used computed tomography perfusion(CTP)and TCD to evaluate these changes of cerebral hemodynamic after operation in two groups,and analyzed their clinical outcomes.4.Statistical analysis:Line chart was used to show the change of opening ratio of cerebral collateral circulation before and after operation;box chart was used to show the change of CTP and TCD parameters before and after operation;bar chart was used to show the improvement ratio of nerve function defect corresponding to responsible vessel after operation.The measurement data were expressed as(x±s).Paired t-test was used to compare the differences of CTP and TCD parameters before and after operation,and independent sample t-test was used to compare the differences of parameters between two groups.Counting data were expressed as an example(%)and χ2 test was used for comparison between groups.Results1.CTA showed changes of cerebral collateral circulation:After CEA,the opening rate of ACoA was increased significantly(pre-operation 4.9%vs.postoperation 36.6%,P<0.01),all the PCoA on the operated side were closed(pre-operation 51.2%vs.postoperation 0%,P<0.01),but on the non-operated side remained unchanged(pre-operation 46.3%vs.postoperation 46.3%,P>0.05).2.Changes of CTP parameters:Before and after surgery comparison,the CTP parameters on the operated side of two groups and on the non-operated side of the ACoA open group were significantly improved(P<0.01),but the CTP parameters on the non-operated side of the ACoA non-open group had no significant differences(P>0.05).Postoperative inter-group comparison,there were no significant differences in CTP parameters on the operated side between two groups(P>0.05),but the CTP parameters on the non-operated side in the ACoA open group were significantly improved than those in the ACoA non-open group(P<0.01).3.Changes of TCD parameters:Before and after surgery comparison,the Vm and PI of the MCA on the operated side of two groups and on the non-operated side of the ACoA open group were significantly increased(P<0.01),but these parameters on the non-operated side of the ACoA non-open group had no significant differences(P>0.05).Postoperative inter-group comparison,there were no significant differences in Vm and PI of MCA on the operated side between two groups(P>0.05),but the Vm of MCA on the non-operated side in the ACoA open group were significantly higher than those in the ACoA non-open group(P<0.01).4.Clinical outcomes:The neurological function defects of the responsible vessel on the operated side were improved in both groups,but on the non-operated side were different.The improvement rate in the ACoA open group was higher than that in the ACoA non-open group(46.7%vs.19.2%).ConclusionAfter unilateral CEA for severe stenotic lesions of bilateral ICA,the opening of ACoA can simultaneously improve the cerebral perfusion on the non-operated side.