Basically And Clinical Study On Carotid Artery Atherosclerotic Stenosis

Cerebral arterial thrombosis is common frequently-occurring disease in mankind,the incidence of cerebral arterial thrombosis a year in China is 0.12～0.18％, casefatality is 0.08～0.12％, arterial stenosis is the main cause in these factor.Carotid artery atherosclerotic is an important risk factor of cerebral arterialdisease, 20％～30％apoplexy results from carotid artery atherosclerotic stenosis, as aresult, carotid artery atherosclerotic stenosis is the hot spot for pay close attention toin neuroscientist. Thomas Willis founded early total obstruct of carotid artery inautopsy in 1684, Chiar emphasized external skull carotid artery obstruct was theimmediate cause of stroke,Fish researched the pathology of carotid artery stenosis in 50's last century andsuggested: it might be effective to prevent stroke for surgical process in carotid arterycrotch; 3 Argentina doctors finished a resects of carotid artery stenosis and MCA-STAbypass for a 41 years man with anemia and right hemiplegics; DeBakey successfulfinished a carotid endarterectomy (CEA) for a 53 years old people with repeatedlytransient ischemic attack (TIA) in 1953; After this, a large number of scholar reportedmany operations, but in 80's, 20 century, some poor curative effect made physiciansto suspect the effect of CEA, This suspect and controversy resulted sharp descend ofthe number for CEA surgery.To solute the question of the effect of CEA, some large-scale to look up and tocompare random clinical trial has been done by the end of 90's last century, representative were:①North American Symptomatic Carotid Endarterectomy Trial(NASCET, 1988～1991),②European Carotid Surgery Trialists' CollaborativeGroup(ECSTCG; 1981～1991),③Asymptomatic Carotid Arthrosclerosis Study(ACAS,1987～1993). They draw some important conclusion:①CEA is extremely utility forhomonymy carotid artery weight stenosis with near time hemisphere ischemic andTIA;②to carotid artery weight stenosis with cerebral ischemia symptom, CEA is thebest therapeutic tool;③CEA has apparent curative effect in prevent stroke for nosymptom carotid artery stenosis without operation contraindicated people.To suffer from the test report enhearten above-mentioned, the case of particularCEA in the world improved rapidly since 1990's, literature number report improvedmultiplication, too. The technical improvement made the complication of CEA lessand less, as a result, there were about 100 thousand people received CEA per year bythe end of 1980's.But CEA as an operation still has determinate trauma and chanciness, clinicaldoctors begun to find a more micro-injury way to solve the question of carotid arterystenosis. Dotter firstly described percutem intracavity arterioplasty (PTA), Kerber cutopen blood vessel with sacculus dilatation to treat carotid stenosis in 1980, Mathiasfinished PTA for a woman with carotid artery fibrodysplasia in 1979 afterexperimentize on animal, successfully finished the first carotid artery stenosisstenting in 1989, then, the cases of CASS appeared unceasing in the world. PTA cancause endomembrane tear apart,plaque shifting and embolus desquamate and vesselwall elasticity recovery, this can result vessel secret compartment even block up.Cerebral embolism and restenosis became chief factor of effecting curative effect.With the improvement of technically achievement ratio in stentt insertion (98％-99％)and descend of complication, CASS appear a tendency to replace CEA gradually. InChina, from 1994 to September 2005, there were 297 articles about carotid arterystenosis research, in these articles; there were 1578 cases with CEA but 4165 casesIn spite of these, the CASS still has determinate complications:①hyperperfusion injury. Which is a complication founded first after CAS.②cerebralinfarction. It is the main complication after CAS.③The place of arteriorpuncturehaematoma.④carotid arteriospasm, secret compartment and obstruction.⑤cardiac rhythm Brady and hyperpiesia.⑥stem restenosis and stentdeformation.This research undertakes the animal experiment of carotid artery atheroscleroticstenosis emphasize, observed and summarize the preliminary experiment of CASS inthe cases with carotid artery atherosclerotic stenosis.PartⅠThe establishment of pig model of carotid atherosclerotic stenosisObjective: To establishes the methods and factors affecting the development ofa stable and reliable animal model suitable for experimental studies of surgicaltreatments of carotid atherosclerotic stenosis (CASS).Methods: Using 10 normal pigs, lesions were created by hot air-drying isolatedsegments of carotid arteries. Empirical procedure: pig to anesthetize→recipe blood ofear to check blood-fat→to lesions double common carotid artery by hotair-drying→feeding the pigs a diet of 6％cholesterol, 12％peanut oil for 2months→recipe blood of ear to check blood-fat→inspected by Doppler color flowimaging, DSA and CTA→reset pathological changes ICA to pathological exam.Evaluated the stenosis of carotid arteries and observed the character of pathologicalchanges. The method of ICA endarterium lesions by hot air-drying: to reveal anddissociation one side CCA for 8 cm by aseptic technique, to obstruct by aneurysmclip in distant and near place, discussion blood engthways, aerates it by electricityaerate for 3 minutes spur 20cm after turnover; rinsed by saline water, sutured innatural position, recanalization after replaced by saline water. To sew up whole rangesoft tissue. Intramuscular penicillinu 80 pan- unit after method at once, afterwardsadds norfloxacin in animal feed, 0.4g~*3/D, for 5 days. Determination extent of ICA:using the software in DSA to precision measurement the diameter of most stenosis ineach ICA (DMS) and the diameter of distal end of normal ICA (DCC). The ratio ofstenosis=(DCC-DMS)/DCC~*100％. The judgement of external stenosiss: stenosisratio＜70％were unable to satisfied the requirement for test, stenosis rati≥70％wereable to satisfied the requirement.Results: No animal dead. In 20 vasculars, 19 with severe stenosis were all morethan 70％, the ratio of success is 95％. No completely vascular occlusion.Determination of Pig blood-fat: LDL-C increased about 15 times than foundation after feed by high lip foods for 2 months, otherwise, the HDL-C in TC which haveresist scleratheroma function increased about 9 times. The Doppler color flowimaging indicates that blood flow rate in injured place accelerates obviously after 2months feeding than before, peak amplitude raise up, both DSA and CTA demonstrateobviously stenosis in ICA. The pathological studies suggested that the atheroscleroticlessions were belong to the mature fibrous plaque period as fed the atherogenic diedfor 2 months.Conculsion: The carotid arteries of pig have a well same as mankind inantatimical and physiology. Injured and fed as described by the authors, thepercentage of stenosis and pathological changes of the animal model is stable andreliable, and it meets the demand of experimental studies of surgical treatment ofCASS.PartⅡPestenotic and poststenotic hemodynamic alter in the ICA of pit modelObjective: To study the prestenotic and poststenotic hemodynamic alter of ICAand Intracal arterial in pig.Methods: To adopt the method stated by partⅠ, to establish the pig model ofcarotid atherosclerotic stenosis, before and after modeling, using 3D Doppler colorflow imaging made by Acuson company(USA), with 6MHz scarching unit toexamine the characteristic of blood flow via the neck area of the body; hemodynamicparameter in each blood vessel include: peak systolic velocity (PSV), ending diastolicvelocity(EDV), mean glow velocity(MVF) and pulsatility index(PI)。Location andcontent for detect were same as preparation.To record the diameter of stenosis (d), the diameter of distal end of normalICA(D), character of plaque and PSV in most stenosis place, to calculate the stenosisextent of blood vessel and volume of blood flow per minute (Q) by below formula。stenosis extent of inner diameter=(D-d)÷D×100％Q=Vm×S×60 Among the total, S is blood vessel's areas, Vm is time average blood flow rate.Results: After the establishment of pig model of carotid atherosclerotic stenos,all MCA's PSV have negative acceleration [post operation (95.78±9.86)cm/s, preoperation (72.04±12.24)cm/s, P＜0.05]. ICA's PSV after 2 months post operationincrease significantly than preparation [post operation (244.76±52.30)cm/s, preoperation (l13.09±19.92)cm/s, P＜0.05]; all volume of blood flow decreasesignificantly than pre operation [post operation (215.18±41.55)ml/min, pre operation(382.68±33.26)ml/min, P＜0.05]. After feed by high lip foods for 2 months postoperation, The Doppler color flow imaging indicates that pig's ICA lumina becameobviously stenosis, endomembrane thickening and different degree atheromatousplaque adnexal wall. after founding model, velocity of ICA was (104.9±12.0)cm/s,but the velocity pre operation was (54.7±7.4)cm／s, The Doppler color flow imagingindicates feed by high lip foods for 2 months post operation, carotid artery pulse ofpig present a type of high resistance, RI rise obviously[post operation (0.91±0.09),pre operation (0.28±0.07), P＜0.05].Conculsion:①The Doppler color flow imaging is simple, quickly andaccurately, which can clear display the changes of endarterium, understand the size ofplaque, position and influence to blood flow.②While ICA of pig become severe stenosis, intracal arterial perfusion descend,appears depress of blood flow rate: arterial perfusion of double hemisphere and circacirculation changes asymmetry, otherwise outside cranium artery appears increase ofblood flow rate, Doppler color flow imaging indicates peak value raise up, blood flowrate obviously decreases obviously.③Although DSA is the "gold standard" of diagnose and evaluation to vascularlesion, but respecting it's injury,expensive and uneasy to accept, it can't to a screenand repeatedly detect way. Doppler color flow imaging has simply, repeatedly andeconomical, as a result, it is a reliable indicator to diagnose intracal and cervix bigvessel stenosis. PartⅢInitial follow-up of Endovascular stenting for stenosis of internalcarotid arteryObjective: To conclude the initial experience of percutaneous transluminalstenting for stenosis of internal carotid artery (ICA).Methods: From May, 2002 to November, 2005, 32 CEVD patients wereidentification by outpatient because of repeated transient ischemic attacks (TIA) orcerebral infarction. Which clinical manifestation and neuroimagings correspondedstand of NASCET, 23 males, 9 females, 55～79 years old, average age is 64.3 yearsold. 24 cases display TIA, 2 display severity dizzy, 6 were old cerebral infarction,without severity nerve functional disturbance. In these patients, 23 cases withhypertensive disease, 15 cases with hyperlipemia, and 7 with diabetes.Imaging data: all cases received MR scanning Preoperative, partly received DWIand PWI weighted imaging to understand if there was new infarction, all patientsreceived Doppler color flow imaging, DSA results shows: 23 cases had stenosis infurcation of CCA, 9 stenosis situated with sub terminal ICA. The stenosis degreewere all over 70％, The mean degree of stenosis was (76±20)％, 8 cases were over90％, mean length of stenosis was 1.6～4.2cmAntiplatelet prepare should be adopt 3～5 days pre operation, routine monitoringin operation, with local anesthesia or total anesthesia, then DSA of cerebral finished,to evaluate the result of DSA, confirm the responsibility vessel, Under the guaid ofRoadmap of DSA, self-expandable stents were placed into the stenosis.Post-expanded was selected to execution. Retrieve protective umbrella, intramuscular0.4 ml Low Molecular Heparin, 1/12h, 3 days. At the same times, take orallyclopidogrel and aspermin, one kind of antiplatelet treated more than 6 months postoperation and follow-up.Results: The symptoms of patients were relieve and vanished, 8 patients withstenosis degree over 90％received Amii sacculus expanding, No operative failure, thestents were placed in the exact place of stenosis. Among 41 stenosis in 32 patientswere successfully treated with self-expansion stents. The mean degree of stenosisreduced from(76±20)％to (15±8)％. No other complications occurred except a frontallobe cerebral infarction occurring in 1 patient during operation. All cases received follow-up with Doppler color flow imaging, 16 received DSA follow-up, No TIA orinfarction happened in the 5-18months (mean 10.7 months) of follow-up. Clinicalsymptoms were significant improved than pre-operation. 7 cases after stenting for 3months founded stenosis but less than 50％, smooth and glossy in stent, thinking therewere blood vessel endothelium formed and patients without the symptom ofinfarction, as a result, no further treatment to adept.Conclusion: Endovascular stenting is a safe and effective way in the treatmentof carotid artery stenosis. Suitable cases are the precondition and important conditionto success of CASS. The most complication of CASS is infarction; adoptingprotective umbrella can decrees the take place of stroke. Strictly process aroundoperative, fineness procedure and closely observe, handle are fundamentalmeasurements to avoid failed.