颈动脉流场改变对斑块稳定性影响及脑梗死分型特点分析

目的探讨颅外段颈动脉狭窄所致血流动力学变化对斑块稳定性影响;分析脑梗死分型与责任血管狭窄程度、斑块稳定性关系,为脑梗死发病机制、临床诊断、治疗和预防提供重要依据。方法对168例急性脑梗死患者分别行64排CT头颈部血管成像(CTA)及彩色多普勒血流显像仪(CDFI)检查,部分经CTA证实为中、重度狭窄及闭塞者于脑梗死恢复期行DSA检查,根据其责任血管狭窄程度,将168例患者分成颈动脉正常组、轻度狭窄组、中度狭窄组,重度狭窄组及闭塞组,结合CDFI及CTA评价斑块性质及流场改变,对梗死灶进行急性脑梗塞的牛津郡社区卒中计划(OCSP)分型,再根据CTA所示脑梗死部位,将患者分为皮质、基底节区、放射冠和后循环梗死4种亚型。观察流场改变对斑块稳定性影响并对比不同程度颈动脉狭窄后脑梗死临床分型特点。结果 168条责任血管,正常17.9%,轻度狭窄22.6%,中度狭窄30.9%,重度狭窄14.8%,闭塞14.3%,中度狭窄比例最高。狭窄程度大于50%即可导致流场改变,血流速度增快,湍流形成,斑块不稳定性增加,以脂质斑及混合斑比例最高。临床部分前循环梗死(PACI)多见,重度狭窄及闭塞组颈动脉斑块以混合斑多见,临床以分水岭梗死多见。轻度狭窄组,多为纤维斑块,临床以腔隙性梗死(LI)多见。结论颈动脉中度狭窄因特殊的血流流场变化导致斑块不稳定性增高,易发生动脉-动脉栓塞。

Effect of carotid artery flow changes on the stability of plaque and typing characteristics of cerebral infarction

objective To observe the influence of hemodynamic changes caused by extracranial carotid stenosis on the plaque stability, and analyze the relationship of cerebral infarction classification, criminal artery stenosis degree and plaque stability to offer evidence for evalu- ating nosogenesis,clinical diagnosis, treatment and prevention of cerebral infarction. Methods CDFI, CTA were performed in 168 patients with acute cerebral infarction, some moderate and severe and occlusive carotid artery which were demonstrated by CTA and CDFI were further checked by DSA during convalescence. Totally 168 acute cerebral infarction patients were divided into 5 groups based on the criminal artery stenosis degree. To evaluate the plaque stability and flow field changes with CDFI and CTA, OCSP clinical classification and brain image clas- sification were finished according to CTA. Patients were classified into 4 subtypes, namely cortical infarction, basal ganglion infarction, corona radiata infarction and posterior infarction, according to the lesion distributions. Observe the changes of flow field and stability of plaque, and compare the relationship between different degree of stenosis and the classification of lesion of infarction. Results Among the 168 criminal arteries,there was 17.9% of normal,22.6% of mild stenosis,30.9% of moderate stenosis,14.8% of severe stenosis,and 14.3% of occlu- sion,and the moderate stenosis proportion was the highest. When the stenosis degree was over 50% ,it may lead to the changes of flow field, speeding up of blood flow,forming of turbulent flow,and increasing of plaque instability in which lipid plaque and admixture plaque was the highest. PACI is the commonest in all moderate groups. Admixture plaque is usually seen in severe stenosis and occlusion, while fibrous plaque is usually seen in mild stenosis. Conclusion Moderate carotid stenosis may lead to the increase of plaque instability as a result of the changes of flow field, and it may prone to artery-artery embolization.