The Cerebral Hemodynamic Monitoring In Carotid Endarterectomy And The Stady Of Plaque Stability

The paper involved two aspects:(1) a study about the changes of cerebralhemodynamics in carotid endarterectomy (CEA);(2) Research the expression of CD40andmatrix metalloproteinase (MMPs) in CEAplaques and the impact on plaque stability.Part Ⅰ:A StudyAbout The Changs Of Cerebral Hemodynamics InCarotid EndarterectomyObjective To prospectively study how to prevent cerebral ischemia and hyperperfusionsyndrome during carotid endarterectomy (CEA).Methods29cases of patients undergoing CEA (35surgeries were done in total) withcarotid artery stenosis were divided into bilateral and unilateral stenosis groups. DuringCEA, the regulation of blood pressure is according to changes of the ipsilateral middlecerebral artery mean flow velocity (MCA Vm) detected by Transcranial Doppler (TCD): ifthe MCA Vm after carotid artery occlusion is lower than70%of that before occlusion, theblood pressure should be increased; and the MCA Vm after release cross was higher than100%of that before carotid artery occlusion, the blood pressure should be decreased.Before and after surgery, all cases in the study were underwent TCD, Color doppler flowimaging (CDFI), Magnetic resonance angiography (MRA) and/or Computed tomographyangiography (CTA) and/or Digital subtraction angiography (DSA) to diagnosis thevascular stenosis and recanalization; underwent Computed tomography perfusion (CTP) toevaluate the cerebral perfusion; underwent Computerized tomography (CT) and Magneticresonance imaging (MRI) to evaluate whether the parenchymal hemorrhage or ischemicchanges; underwent TCD to evaluate the establishment of collateral circulation beforesurgery. Results (1) In the two groups: the MCA Vm of the intraoperation side before carotidartery occlusion was decreased as compared with that before anesthesia (P=0.000); Aftercarotid artery occlusion, the MCAVm was decreased slightly as compared with that beforeocclusion (P>0.05), and the blood pressure increased (23.76±9.15)%(P=0.000); TheMCA Vm after release cross was higher than that before occlusion（P=0.000), the bloodpressure decreased (6.70±6.89)%(P=0.000).(2) Between the two groups: After carotidartery occlusion, the MCA Vm of the intraoperation side in bilateral stenosis group wasdecreased than in unilateral stenosis group (P<0.05), the enhance rate of the blood pressurewas higher than in unilateral stenosis group (P<0.01). After release cross, the reduce rate ofthe blood pressure in bilateral stenosis was lower than in unilateral stenosis group (P<0.05),the MCA Vm between the two groups have no statistic difference (P>0.05).(3) Aftersurgery, the cerebral perfusion of all patients of the intraoperation side was improvedversus before surgery.Conclusion During CEA, TCD can real-time monitoring the changes of cerebralhemodynamics, evaluate the cerebral perfusion, guide the anesthetist to regulate the bloodpressure timely, so as to improve the success rate of surgery significantly. Part Ⅱ: Research the expression of CD40and MMPs in CEAplaquesand the impact on plaque stabilityObjective Study the expression level of CD40and matrix metalloproteinase (MMPs) invulnerability, stability carotid atherosclerotic plaque. Investigate the relevance of CD40and MMPs expression and the impact on plaque stability.Methods35cases of specimens with carotid atherosclerotic plaque were collected fromCEA. According to the evaluation of the plaque stability by CDFI before surgery, whether find microembolic signals (MES) by TCD in one week before surgery and the presence ofacute ischemic stroke events, all specimens were divided into stable plaque group andvulnerable plaque group, detected the mRNA and protein expression level of CD40andMMPs in each group using realtime fluorescent quantitative PCR (Realtime PCR) andWestern blotting assay.Results (1) Realtime PCR test results: The mRNA expression level of CD40and MMP-9in vulnerable plaque group was significantly higher than in stable plaque grouprespectively (P<0.01). There was no statistically significant differences in the mRNAexpression level of MMP-1, MMP-2, MMP-14between the two groups (P>0.05); Therewere significantly positive correlation between CD40mRNA and MMP-9mRNA(r=0.9006, P<0.0001), and positive correlation between CD40mRNA and MMP-2mRNA(r=0.4322, P=0.0135). But there was no significant correlation between CD40mRNA andMMP-1mRNA (r=0.0282), CD40mRNA and MMP-14mRNA (r=0.0876)(P>0.05).(2)Western blotting test results: As the mRNA expression level of CD40and MMP-9invulnerable plaque group was significantly higher than in stable plaque group respectively,and there was a positive correlation between CD40mRNA and MMP-2mRNA, CD40mRNA and MMP-9mRNA, therefore, we selected the protein expression level of CD40,MMP-2and MMP-9to analysis. The results show that the protein expression level ofCD40, MMP-2and MMP-9in vulnerable plaque group was significantly higher than instable plaque group.Conclusions CD40is not only involved in the formation of atherosclerotic plaque, butalso may influence the stability of atherosclerotic plaques by regulating the expression ofMMP-2and MMP-9, promoting plaque rupture, resulting in the occurrence of ischemicstroke.