Wall shear stress in carotid artery and its role in the development of atherosclerosis

Atherosclerosis is associated with systemic risk factors such as arterial hypertension, hyperlipidemia, diabetes mellitus and smoking. Yet it is a focal disease, predominantly affecting predisposed areas. The principal local hemodynamic factor is wall shear stress, i.e. the frictional force acting tangentially on the endothelial cell surface. The effect of wall shear stress on the endothelium depends on its magnitude and direction, as well as on the local vessel geometry and blood flow characteristics. Wall shear stress is an important determinant of endothelial function and phenotype. The article deals with the influence of wall shear stress on endothelial cell function, atherosclerotic plaque formation, and vascular remodelling in the common carotid artery.     

Wall shear stress in the stented superficial femoral artery in peripheral arterial disease

Objective

Local changes in wall shear stress (WSS) contribute to vascular wall thickening and subsequent stenosis. Restenosis after stenting is a major concern, especially in the superficial femoral artery (SFA) of patients with peripheral arterial disease (PAD). Local alterations in WSS after stenting might contribute to restenosis/reocclusion. To test the hypothesis that WSS is impaired along the stented SFA segment, we studied the profile of WSS along the femoro-popliteal axis after stent placement in a cross-sectional design.

Methods

Eighty-seven patients with PAD (89 limbs) were included one day after stenting of the SFA. Flow velocities (peak and mean) and vessel diameter were measured by duplex ultrasound in five predefined segments along the femoro-popliteal axis, at rest and after exercise (30 toe raises); WSS (peak and mean) was calculated from flow velocities, vessel diameter and whole blood viscosity.

Results

WSS progressively declined along the stented segment at rest (peak WSS, p < 0.0001; mean WSS, p < 0.05); after exercise, WSS increased in all segments (all p < 0.001), but, again, progressively declined along the stent (peak WSS, p < 0.0001; mean WSS, p < 0.05). The internal vessel diameter remained unchanged after exercise in the stented and in the non-stented parts of the femoro-popliteal axis (all p > 0.05).

Conclusion

In PAD patients with SFA stenting WSS is impaired along the femoro-popliteal axis. The consequences of this finding in terms of local effects on the vessel wall that might favor restenosis/reocclusion needs further investigation.     

脑梗死患者颈动脉病变与眼底动脉硬化的相关性分析

目的探讨脑梗死患者颈动脉病变与眼底动脉硬化的相关性。方法选择脑梗死患者177例,分别进行头颅CT或MRI、颈动脉超声和眼底照相检查,评价颈动脉内膜中层厚度、颈动脉狭窄及眼底动脉硬化分级。结果177例患者中,颈动脉无病变10例(5.6%),颈总动脉内膜中层厚度增厚22例(12.4%),任意颈动脉斑块形成121例(68.4%),颈动脉狭窄24例(13.6%)。正常35例(19.8%),眼底动脉硬化改变142例(80.2%),其中Ⅰ级69例(39.0%),Ⅱ级31例(17.5%),Ⅲ级42例(23.7%)。眼底动脉硬化与颈动脉内膜中层厚度、颈动脉狭窄相关(P<0.05),但眼底动脉硬化各单项指标与颈动脉内膜中层厚度和颈动脉是否狭窄无相关性(P>0.05)。结论眼底动脉硬化与颈动脉病变存在一致性,眼底照相可作为辅助方法帮助评价全身血管情况,协助颈动脉疾病的诊断。     

颈动脉易损斑块与缺血性脑卒中复发的相关性研究

目的对颈动脉斑块进行评价,分析斑块性质、形态及其危险因素与缺血性脑卒中复发的相关性。方法选择经头颅CT和(或)MRI确诊为缺血性脑卒中复发患者209例,应用CT血管造影联合彩色多普勒超声检查证实122例有颈动脉斑块,根据斑块性质分为易损斑块组86例,稳定斑块组36例,分析斑块性质、形态,观察发生缺血性脑血管事件相关因素,比较2组缺血性脑卒中复发的时间、分布及狭窄的关系,Cox风险比例模型分析缺血性脑卒中复发与颈动脉斑块等危险因素间的相关性。结果 209例患者中,颈动脉斑块122例,占58.4%。与稳定斑块组比较,易损斑块组年龄更高,高血压和冠心病的比例更多(P<0.05)。Cox回归分析显示,易损斑块与冠心病是缺血性脑卒中复发的危险因素。结论颈动脉斑块性质、形态和冠心病是缺血性脑卒中复发的危险因素。     

缺血性脑血管病彩色多普勒、经颅多普勒联合检测结果分析

目的 研究缺血性脑血管病发病与颈部动脉粥样硬化狭窄程度和斑块性质的关系.方法 采用彩色多普勒和经颅多普勒技术对缺血性脑血管病患者100例及健康者40例（对照组）进行检测,观察颈动脉解剖形态、内膜情况,有无斑块形成及斑块大小、形态、回声特征,颅内外动脉管腔是否狭窄和狭窄程度.结果 缺血性脑血管病组颈动脉不均质、不规则斑块的检出率及其颅内外动脉狭窄的比例均明显高于对照组,且颅内动脉狭窄的比例高于颅外动脉.结论 颈动脉粥样硬化斑块的性质及颅内外动脉狭窄与缺血性脑血管病的发生密切相关.     

血栓前体蛋白与老年脑梗死患者颈动脉粥样硬化的相关性研究

目的探讨血栓前体蛋白与老年脑梗死患者颈动脉粥样硬化之间的关系。方法采用酶联免疫吸附法测定44例老年动脉粥样硬化性脑梗死患者(脑梗死组)和30例老年健康对照者(对照组)血浆血栓前体蛋白水平,并对脑梗死患者进行颈动脉超声检查,检测颈动脉内膜中层厚度,并分析血栓前体蛋白水平与颈动脉内膜中层厚度的关系。结果与对照组比较,脑梗死组患者血栓前体蛋白[(9.27±2.29)mg/Lvs(2.20±0.30)mg/L,P=0.000]、纤维蛋白原[(3.79±1.06)g/L vs(3.30±0.69)g/L,P=0.012]和D-二聚体[(1154.05±1038.54)μg/L vs(696.33±443.18)μg/L,P=0.035]明显升高。脑梗死组颈动脉内膜中层厚度≥1.0mm患者血栓前体蛋白水平明显高于内膜中层厚度<1.0mm患者[(10.12±2.46)mg/L vs(7.79±0.30)mg/L,P<0.01];脑梗死组患者血栓前体蛋白与颈动脉内膜中层厚度呈正相关(r=0.518,P<0.05)。结论老年脑梗死患者的血浆血栓前体蛋白水平显著升高,且与颈动脉粥样硬化密切相关。     

Plasma thrombin-cleaved osteopontin elevation after carotid artery stenting in symptomatic ischemic stroke patients

Atherothrombosis is the primary pathophysiology that underlies ischemic cerebral infarction. Osteopontin (OPN) is produced in atherosclerotic lesions and is cleaved by activated thrombin. We hypothesized that the rupture or damage of an unstable atherosclerotic plaque increases plasma levels of thrombin-cleaved OPN (trOPN). This study included 90 patients who received carotid angioplasty with stenting (CAS), 23 patients with essential hypertension (EHT) and 10 patients who were treated with carotid endarterectomy (CEA). The CAS patient group included 36 patients that had pre- and post-operative blood tests, diffusion-weighted imaging (DWI) using cerebral MRIs and estimated thrombus debris within the protection device. Immunohistochemistry of CEA specimens revealed that trOPN was detected around intra-plaque vessels. The highest tertile of plasma trOPN levels in CAS patients was higher than trOPN levels in EHT patients. Post-operative trOPN levels were significantly higher in symptomatic compared with asymptomatic patients (P=0.003). New ipsilateral DWI-positive patients revealed higher post-operative trOPN levels (P=0.003) and a higher grade of thrombi (P<0.001) than DWI-negative patients. TrOPN may be a novel biomarker that reflects the atherothrombotic status in ischemic stroke.     

兔颈动脉顶端动脉瘤的血流动力学数值模拟切应力分析

目的探讨颅内顶端动脉瘤的血流动力学特点,分析动脉瘤生长、破裂的机制.方法选取5只兔颈动脉顶端动脉瘤模型,结合医学影像学资料,采用计算流体力学（CFD）有限元方法的软件,对兔颈动脉顶端动脉瘤的血流动力学行数值模拟,并对瘤颈、瘤壁等部位切应力大小随时间变化情况及分布进行分析.结果顶端动脉瘤在整个心动周期里切应力几乎都在迅速变化,变化时程与血流速度的变化时程一致,切应力主要存在于瘤颈,动脉瘤颈入口边界切应力0.21 T达峰值,为0.83 Pa;出口边界切应力0.32 T达峰值,为0.38 Pa;动脉瘤壁切应力接近于0.结论顶端动脉瘤瘤壁切应力是促进动脉瘤生长、扩大的可能原因之一.CFD数值模拟是一种反映动脉瘤血流动力学较好的方法.     

脑卒中高危人群氧化应激指标与颈动脉粥样硬化危险因素分析

目的调查贵州省福泉县脑卒中高危人群氧化应激指标与颈动脉粥样硬化(CAS)关系,分析CAS相关危险因素。方法采用随机整群抽样法对福泉县6个镇、4个乡常住居民9500例进行健康问卷调查、体格检查、实验室检查、心电图检查及颈动脉彩色超声检查。共筛选出脑卒中高危人群1032例,随机选取高危人群360例,再根据颈部血管彩色超声筛查结果分为颈动脉正常组78例、颈动脉内膜中层厚度(IMT)增厚组131例及CAS组151例,检测氧化应激指标氧化型低密度脂蛋白(ox-LDL)及超氧化物歧化酶(SOD)变化,采用单因素和多因素logistic回归分析CAS的危险因素。结果 CAS组ox-LDL明显高于颈动脉正常组和IMT增厚组[(564.7±70.6)μg/L vs(434.5±46.3)μg/L,(488.1±51.2)μg/L,P<0.05],SOD明显低于颈动脉正常组和IMT增厚组[(41.0±18.1)kU/L vs(67.4±9.5)kU/L,(58.6±10.3)kU/L,P<0.05]。logistic回归分析显示,年龄、吸烟、高血压、脑卒中史或家族史、空腹血糖、LDL-C、ox-LDL升高是导致CAS的独立危险因素。结论加强脑卒中高危人群管理,积极指导控制各项危险因素,调控患者氧化应激反应,可延缓CAS,降低脑卒中发生。     

脂蛋白相关磷脂酶A2在颈动脉粥样硬化和缺血性卒中中的作用

脂蛋白相关磷脂酶A2(lipoprotein-associated phospholipase A2,Lp-PLA2)是磷脂酶A2超家族的一个亚型,主要由巨噬细胞和淋巴细胞产生.Lp-PLA2选择性水解低密度脂蛋白颗粒表面的氧化型磷脂,产生溶血磷脂胆碱和氧化型游离脂肪酸.Lp-PLA2表达于动脉粥样硬化斑块和不稳定斑块纤维帽内的巨噬细胞.研究表明,缺血性卒中患者血浆Lp-PLA2活性显著增高,而Lg-PLA2可能成为预测缺血性脑血管事件的独立危险因素.选择性LP-PLA2抑制剂可减轻炎症反应,增强斑块稳定性,抑制动脉粥样硬化斑块形成,有可能成为抗动脉粥样硬化斑块形成的一类新型药物.     

症状性颈动脉狭窄对急性脑梗死患者短期预后的影响

目的评估症状性颈动脉狭窄对急性缺血性脑梗死短期预后的影响。方法选取前循环急性缺血性脑梗死患者421例,通过血管影像学检查评估颈动脉,根据颈动脉狭窄程度分为颈动脉重度狭窄组44例,中度狭窄组43例和轻度或无狭窄组334例。采用多元logistic回归分析评估颈动脉狭窄程度与急性脑梗死短期预后的关系。结果与中度狭窄组和轻度或无狭窄组比较,重度狭窄组病死率、神经功能恶化和不良转归比例更大,住院时间更长(P<0.05,P<0.01)。多元logistic分析显示,与中度狭窄组比较,重度狭窄组患者死亡风险更高(OR=2.564,95%CI:0.469¹4.009),神经功能恶化(OR=2.037,95%CI:0.74214.009),神经功能恶化(OR=2.037,95%CI:0.742⁵.922)、不良转归更严重(OR=2.347,95%CI:0.9885.922)、不良转归更严重(OR=2.347,95%CI:0.988⁵.577)和住院时间延长(OR=7.000,95%CI:2.6625.577)和住院时间延长(OR=7.000,95%CI:2.662¹8.409)。结论症状性颈动脉重度狭窄是急性脑梗死短期不良预后的独立预测因素,因此,针对症状性颈动脉重度狭窄的患者应尽早采取积极的干预措施。     

颈动脉易损斑块对缺血性脑卒中预后的影响

目的探讨颈动脉易损斑块与缺血性脑卒中预后的关系。方法经头颅MRI证实的首发或再发缺血性脑卒中患者152例,根据诊断分为易损斑块组56例,非易损斑块组96例,并进行CT血管成像联合颈动脉超声检查,分析斑块性质、形态,发病后根据美国国立卫生研究院卒中量表(NIHSS)评分对患者的神经功能缺损情况进行评估,采用改良的Rankin残障量表(mRS)评估预后,评估各项危险因素,动态观察其入院后7、14、30d时NIHSS评分、mRS评分、梗死灶体积,观察分析患者的脑血管事件。结果与非易损斑块组比较,易损斑块组7、14、30d NIHSS评分及mRS评分所占比例明显增高,大面积脑梗死体积明显增多,差异有统计学意义(P<0.05,P<0.01)。logistic回归分析显示,颈动脉易损斑块与缺血性脑卒中预后密切相关;NIHSS评分、高敏C反应蛋白、年龄与缺血性脑卒中预后相关。结论缺血性脑卒中易损斑块患者病情重、预后不良,动态观察易损斑块与缺血性脑卒中预后的病情变化程度能够更充分的预测脑卒中的预后。     

Low wall shear stress contributes to atherosclerosis of the carotid artery in hypertensive patients.

Numerous in vitro studies have indicated that low shear stress may contribute to intimal thickening and development of atherosclerosis. In the present study, we investigated wall shear stress in hypertensive patients and its relevance to atherosclerosis in the carotid arteries by means of a non-invasive technique. Fifty-five hypertensive patients and 23 normotensive controls were investigated. Intima-media thickness, number of plaques, internal dimension and blood flow velocity of the carotid artery were evaluated. Wall shear stress was calculated using the Poiseuillean parabolic model of velocity distribution as follows: shear stress = 4 X blood viscosity X central line flow velocity/internal dimension. Hypertensive patients showed increased intima-media thickness and dilated common carotid arterial dimension relative to normotensive controls. There was no difference in blood viscosity between the two groups. Both the mean shear stress and systolic peak shear stress were significantly lower in hypertensive patients than normotensive controls. Further, wall shear stress at both mean and peak velocity was significantly and negatively related to intima-media thickness and number of plaques in hypertensive patients, as well as in the total study population. These findings indicate that structural and functional alterations in the common carotid artery of hypertensive patients further precipitates atherosclerosis through low shear stress.     

高血压伴与不伴缺血性脑卒中患者颈动脉内中膜厚度的研究

目的 :用彩色多普勒超声观察高血压伴与不伴缺血性脑卒中患者颈动脉内中膜厚度 ,探讨颈动脉粥样硬化与缺血性脑卒中的关系。方法 :用HDI 30 0 0彩色多普勒超声观察了 36例无缺血性脑卒中的高血压病患者和 36例伴有缺血性脑卒中的高血压病患者双侧颈动脉内中膜厚度 ,并与 2 8名健康对照进行了比较。结果 :1 3组间空腹血糖、血脂和体重指数及平均年龄无显著性差异 (P >0 0 5 ) ;2 单纯高血压病患者和高血压病伴缺血性脑卒中患者颈动脉内中膜厚度明显高于健康对照者 (P <0 0 1) ,且高血压伴缺血性脑卒中患者颈动脉内中膜厚度明显高于无缺血性脑卒中的高血压患者 (P <0 0 1)。结论 :高血压病患者存在有颈动脉粥样硬化 ,且伴有缺血性脑卒中患者颈动脉粥样硬化程度明显加重 ,提示颈动脉粥样硬化程度可作为预测缺血性脑卒中发生的参考指标。     

缺血性卒中患者踝肱指数与颈动脉粥样硬化性狭窄关系的研究

目的评估缺血性卒中患者踝肱指数（ABI）与动脉粥样硬化性颈动脉狭窄（CAS）的相关性,探讨ABI作为颈动脉狭窄的筛选指标的可行性。方法选取缺血性卒中患者156例,使用血压超声测量仪,测量所有病例的ABI,使用彩色多普勒超声仪检测所有病例的颈总动脉和颈内动脉,研究ABI与颈动脉狭窄的相关性。结果156例缺血性卒中患者中,颈动脉彩色多普勒超声检查（CDFI）显示颈动脉非狭窄组87例,ABI为0．971&#177;0．108;狭窄组69例,ABI为0．828&#177;0．096,两组差异有统计学意义（P〈0．001）。相关分析显示ABI和CAS呈负相关（r=-0．806,P=0．003）。结论ABI与颈动脉粥样硬化狭窄程度呈负相关,可作为颈动脉粥样硬化狭窄的初步筛查手段。     

Intra-arterial thrombolysis in a patient presenting with an ischemic stroke due to spontaneous internal carotid artery dissection.

We describe a case of a 38-year-old male who presented with acute onset of right-sided hemiplegia and aphasia, who was transferred for emergent percutaneous intervention. Angiography revealed a dissection with total occlusion of the left internal carotid artery (ICA) with propagation of thrombus in the distribution of the middle cerebral artery (MCA). Therapy was directed at the MCA and not the ICA. Intra-arterial thrombolysis was performed on the M1 and M2 branches of the left middle cerebral artery, resulting in almost complete resolution of symptoms during the angiography procedure. Heparin was continued postprocedure, and the patient was discharged home on warfarin and aspirin with minimal residual symptoms.     

颈动脉内膜切除术预防老年缺血性脑卒中

目的 探讨颈动脉内膜切除术预防老年人缺血性脑卒中的应用价值。方法 根据狭窄的部位和程度对152例颅外颈动脉狭窄患者采取不同的手术方法,其中包括传统术式46例,外翻术式97例,增加补片9例。结果 手术均获成功,术后脑缺血症状均有改善。颈动脉内膜切除术后的并发症以局部血肿及声音嘶哑为主,术后血压不稳定多见于采用外翻术式后。结论 颈动脉内膜切除术治疗颅外颈动脉狭窄是安全有效的,在预防缺血性脑卒中中有重要价值。     

穿支动脉区脑梗死部位分布的临床研究

目的探讨急性脑穿支动脉闭塞或狭窄所致急性脑梗死的部位分布。方法回顾性分析解放军总医院2008年4月~2013年12月神经内科收治的急性穿支动脉区脑梗死患者369例。根据磁共振弥散加权成像检查确定脑梗死部位,总结分析穿支动脉区脑梗死的部位分布。结果369例患者中,其中放射冠和半卵圆中心23例(6.2%),基底节129例(35.0%),内囊59例(16.0%),单侧丘脑45例(12.2%),中脑11例(3.0%),脑桥78例(21.1%),延髓18例(4.9%),双侧丘脑(Percheron动脉病变)6例(1.6%)。结论穿支动脉区脑梗死最常见于基底节,其次为脑桥。延髓、中脑和双侧丘脑等少见部位的穿支动脉区脑梗死也应该受到重视。     

Relationship of Von Willebrand Factor with carotid artery and aortic arch calcification in ischemic stroke patients

BackgroundLarge population studies have revealed that increased von Willebrand Factor (VWF) levels are associated with an increased risk of ischemic stroke. In previous studies VWF was associated with atherosclerosis in healthy individuals. However, it is yet unknown what the association is between atherosclerosis and VWF levels in patients with ischemic stroke.ObjectivesThe aim of our study was to determine the association of atherosclerosis, measured with recent developed techniques, and VWF levels in a large, well characterized, cohort of ischemic stroke patients and to determine the prognostic value.MethodsWe included 925 consecutive patients with transient ischemic attack (TIA) or ischemic stroke. Calcification volumes (mm³) were scored in the aortic arch and both carotid arteries using multidetector computed tomography (CT) angiography. VWF antigen (VWF:Ag) levels were measured using ELISA.ResultsMean VWF:Ag levels were significantly higher in the presence of calcification in either the aortic arch (1.47 vs. 1.37 IU/ml [P = 0.039]) or the carotid arteries (1.49 vs. 1.34 IU/ml [P = 0.001]). Patients with a large artery atherosclerosis ischemic stroke had significantly higher VWF:Ag levels then the other TOAST subtypes (P < 0.0001). High VWF:Ag levels were associated with an unfavorable outcome (modified Rankin Scale >2 vs. ≤2; 1.64 vs. 1.41 IU/ml, [P < 0.0001]).ConclusionOur study showed a strong association between the extent of atherosclerosis in both the aortic arch and the carotid arteries and VWF levels in patients with TIA or ischemic stroke. Higher VWF levels are found in large artery atherosclerosis and are associated with a poor outcome.     

颈动脉超声在筛查颈动脉狭窄及脑卒中高危人群中的应用

目的应用颈动脉超声筛查颈动脉狭窄,并探讨脑卒中高危人群颈动脉狭窄的发病率。方法选择356例患者,以60岁为界分为≤60岁组83例,>60岁组273例,其中高血压196例、冠心病145例、下肢动脉疾病97例、糖尿病134例,采用双功能彩色多普勒行颈动脉超声检查,并分析。结果与≤60岁组比较,>60岁组患者高血压、糖尿病、冠心病和下肢动脉疾病比例明显升高,差异有统计学意义(P<0.05)。颈动脉狭窄≥50%103例,占28.9%,其中颈动脉狭窄≥70%33例,占9.3%。年龄>60岁(OR=2.281,95%CI:1.191～5.673,P=0.013)、冠心病(OR=2.312,95%CI:1.162～4.593,P=0.018)、下肢动脉疾病(OR=2.135,95%CI:1.093～4.985,P=0.011)是颈动脉狭窄的影响因素。结论老年男性、冠心病、下肢动脉疾病人群是颈动脉重度狭窄的主要危险人群,也是颈动脉超声筛查的主要对象。