高分辨率MRI评价颈动脉粥样硬化斑块的稳定性

高分辨率颈动脉MRI可用于明确颈动脉斑块是否为不稳定斑块，但缺乏大样本研究。法国研究者fflN用MRI对大样本人群进行了颈动脉斑块的研究，并观察斑块的动态变化。该研究对161例颈动脉斑块厚度〉3mm的患者进行了3T高分辨率MRI检查。根据是否有大的脂质核、斑块内出血（IPH）、纤维帽破裂（FCR）和信号增强（GE）等指标进行斑块不稳定性的判断，并对斑块的上述特点与神经功能症状的相关性及随时间的变化进行比较。由于数据质量问题，剔除7例患者。154例患者中，52例为症状性患者，102例为无症状性患者。两组的IPH发生率分别为39％和16％（P=0．002），FCR发生率分别为30％和9％（P=0．001），GE发生率分别为75％和55％（P：0．015），症状性患者显著高于无症状性患者。进行多因素回归分析后，IPH和FCR在两组问差异仍有统计学意义（OR=2．6，P：0．023；OR=2．8，P=0．038）。出现神经功能症状患者IPH发生率始终高于无症状性患者，而FCR发生率仅在神经功能症状出现后15d内差异有统计学意义。研究者认为，高分辨率MRI颈动脉能明确与缺血症状相关的斑块性质，在一定程度上能预测斑块不稳定性，有助于颅外段颈动脉狭窄的治疗。     

中国汉族人群2型糖尿病与脂联素基因SNP-11377位点相关性的Meta分析

目的评价脂联素基因SNP-11377位点与T2DM的相关性。方法采用Meta分析评估SNP-11377位点与T2DM的相关性。异质性检验后采用M-H固定效应模型合并比值比(OR)值,并进行发表偏倚检验。结果 (1)共纳入10篇文献,其中病例组2831例、对照组3035例。(2)异质性检验显示,脂联素基因SNP-11377在各研究间是同质(I2=11.2%,P>0.05),各研究之间不存在异质性。(3)M-H固定效应模型进行数据合并,结果显示合并OR为1.09(95%CI为1.00～1.18,P=0.05)。(4)Begg和Egger偏倚分析均显示无明显发表偏倚。结论脂联素基因SNP-11377G等位基因可能与中国汉族人群T2DM的发病风险相关。     

短暂性脑缺血发作与颈动脉粥样硬化斑块的关系

目的探讨颈动脉粥样硬化斑块与短暂性脑缺血发作的关系。方法应用多普勒超声技术检测84例颈内动脉系统短暂性脑缺血发作患者颅外颈动脉,检测分析颅外颈动脉硬化斑块的分布、狭窄度及超声分型。并将有症状侧与无症状侧进行分析比较。结果短暂性脑缺血发作患者颅外颈动脉硬化斑块以软斑最为多见,其次为混合斑和溃疡斑,差异有显著意义(P<0.01),硬斑和扁平斑无明显差异;无症状侧斑块明显高于有症状侧斑块(60.34%比39.66%,P<0.01);且无症状侧颅外颈动脉中度以上狭窄发生率明显高于有症状侧(29.31%比6.70%,P<0.01)。结论颅外颈动脉粥样硬化是短暂性脑缺血发作发生的重要危险因素,常规进行颈动脉颅外段彩色超声检测,对短暂性脑缺血发作患者颅外颈动脉粥样硬化严重程度及病因评估有重要的参考价值。     

同型半胱氨酸水平与高血压相关性的Meta分析

目的:对有关同型半胱氨酸(Hcy)水平与高血压之间相关性研究报道的数据进行Meta分析。方法:数据采用PubMed、Cochrane图书馆、中国期刊全文数据库和万方数据库。1纳入标准:纳入提供Hcy水平与高血压优势比(OR值)及95%可信区间(95%CI)的流行病学研究。2质量评价:两名作者独立对文献进行筛选和质量评价。3数据提取与合并:两名作者独立对每篇入选研究的关键信息进行提取汇总,并对入选研究进行异质性检验、计算合并OR值及95%CI,发表偏倚检验、亚组分析、Meta回归分析和累积Meta分析。结果:纳入文献12篇,总样本量18 434例。1篇队列研究结果显示Hcy水平与高血压发生无关,非队列研究Meta分析结果显示Hcy水平升高与高血压患病风险有关,合并OR值为2.56(95%CI:1.81~3.64)。各研究间异质性I2=82.4%。亚组分析和Meta回归分析提示,性别、样本量以及研究设计类型可能是异质性来源的一部分。结论:Hcy水平与高血压之间存在明显的关联,提示Hcy水平可能为高血压发病的危险因素。     

幽门螺杆菌感染与缺血性脑卒中及其亚型相关性Meta分析

目的对幽门螺杆菌(Hp)感染与缺血性脑卒中(IS)及其亚型的相关性进行Meta分析,探讨Hp感染是否为IS及其亚型的危险因素。方法计算机检索MEDLINE、EMBASE及Cochrance Collaboration database电子数据库,检索时限为1 995～2009年。由2名评价者对文献的质量进行评价,纳入相关的病例对照研究。采用Cochrane协作网提供的RevMan 5.0软件对纳入文献进行Meta分析,并进一步进行异质性检验、敏感性分析及偏倚评估。结果共纳入11篇相关文献,其中与IS相关9篇(病例组1575例,对照组1 720例),与大动脉粥样硬化性脑卒中(LAA)相关7篇(病例组510例,对照组944例)。异质性检验提示,Hp与IS及LAA的研究间均存在异质性(I~2=58%,I~2=60%)。病例组与对照组的Hp感染率差异存在统计学意义(OR=1.57,95%CI:1.23～1.99);Hp感染与LAA亦存在相关性(OR=2.24,95%CI:1.46～3.43)。敏感性分析提示结果稳定。漏斗图表明存在发表偏倚,提示缺少小样本的阴性结果文献。结论 Hp感染是IS的危险因素,且与LAA的相关性更为密切;病例对照研究论证强度较低,仍需更多大样本及前瞻性研究以证实Hp在IS及其亚型发病中的作用。     

中国人群2型糖尿病与脂联素基因单核苷酸多态性关系的Meta分析

目的 综合评价中国人群脂联素基因(apM1)单核苷酸多态性(SNP)与2型糖尿病的关系.方法 应用Meta分析软件包RevMan4.3.1对各研究结果进行数据合并,计算SNP基因型频数分布合并后OR值及其95%CI;利用Egger分析和失安全系数(Nfs<,0.05>)评估发表偏倚;对各研究结果进行不同分析模式和样本含量的敏感性分析,评价Meta分析结果的稳定性.结果 检索筛选到相关文献9篇.apM1基因的SNP45在各研究间存在显著的异质性(P<0.10).亚组分析表明apM1基因SNP45在以南方人群为对象的研究间异质性较大(P<0.01),是异质性的主要来源.apM1等位基因或基因型SNP45G和SNP45GG、SNP276G和SNP276GG在中国2型糖尿病人群的分布频率显著高于正常糖耐量组,其合并OR值(95%CI)分别为1.50[1.12,2.02]、2.15[1.53,3.02]、1.23[1.03,1.46]和1.26[1.00,1.59](均P<0.05).apM1基因型SNP45TG和SNP276GT在两组人群中的分布没有统计学意义(P>0.05).发表偏倚分析和敏感性分析结果证实上述Meta分析结果是稳定和可靠的.结论 中国人群2型糖尿病与apM1基因SNP关系密切,SNP45G和SNP276G可能是2型糖尿病的危险因素.     

抗血小板药物使用与颈动脉粥样硬化斑块内出血的多对比度磁共振成像研究

目的本研究旨在利用多对比度MRI技术探讨抗血小板药物使用与颈动脉斑块内出血(IPH)之间的相关性。方法回顾性分析经超声检测至少有一侧颈动脉存在粥样硬化斑块的症状性患者108例,其中存在颈动脉IPH患者(IPH患者)41例,无颈动脉IPH患者(无IPH患者)67例。对所有患者进行双侧颈动脉多对比度MR血管壁成像,分析颈动脉IPH与患者临床特征。结果与无IPH患者比较,IPH患者使用抗血小板药物及吸烟比例显著增高(70.7%vs 46.3%,68.3%vs 47.8%,P0.05),使用他汀类药物比例显著降低(29.3%vs 52.2%,P0.05);IPH患者的颈动脉最大管壁厚度、管壁面积、狭窄程度显著高于无IPH患者,差异有统计学意义(P0.01)。logistic回归分析显示,在校正混杂因素之前,使用抗血小板药物与IPH显著相关(OR=2.80,95%CI:1.23～6.41;P=0.014)。进一步校正患者颈动脉最大管壁厚度和颈动脉狭窄后,使用抗血小板药物与IPH之间仍有相关性(OR=3.33,95%CI:1.06～10.45;P=0.039)。结论颈动脉粥样硬化患者抗血小板药物的使用可能与IPH的发生有关,可为颈动脉粥样硬化患者合理、规范使用抗血小板药物提供一定理论参考。     

胱硫醚β-合成酶G919A基因多态性与原发性高血压关系的meta分析

目的综合评估胱硫醚β-合成酶(CBS)基因G919A多态性与原发性高血压(EH)发生风险的关系。方法全面检索Pub Med、Embase、Medline、万方数据库、中国知网(CNKI)、维普资讯,收集CBS基因G919A多态性与EH发生关系的病例对照研究,优势比(OR)及95%可信区间(CI)评估关联强度,应用Rev Man5.3软件对纳入研究进行异质性检验和效应值OR合并,漏斗图评价发表性偏倚;敏感度分析过程,分别以固定效应模型和随机效应模型合并OR值,以评估结果的稳定性。结果共纳入4篇文献6组病例-对照研究,共累计EH组患者1147例,健康对照组1138例,根据异质性检验结果选取固定效应模型或随机效应模型合并数据。Meta分析结果显示:CBS基因919纯合子模型(AA vs GG)、杂合子模型(GA vs GG)、显性模型(AA+GA vs GG)、隐性模型(AA vs GG+GA)和基因频率(A vs G)与EH关系的合并OR(95%CI)分别为3.03(1.95~4.72)、1.49(1.10~2.02)、1.61(1.23~2.10)、2.65(1.26~5.57)和1.55(1.35~1.79),均P0.01。漏斗图未检测出显著的发表性偏倚。结论目前Meta分析表明CBS基因G919A多态性与EH发病相关联,尤其是在中国人群。     

颈动脉周围脂肪密度与颈动脉狭窄以及预后的关系

目的]探讨颈动脉周围脂肪密度与颈动脉狭窄以及预后的关系。 [方法]回顾性连续纳入209例2017年1月—2021年1月在台州市中心医院(台州学院附属医院)收治的颈内动脉颅外段狭窄的患者。通过颈动脉计算机断层成像血管造影评估最狭窄颈动脉轴层以及对侧同一轴层的血管周围脂肪密度;收集患者临床资料;根据指南对狭窄程度进行分度;回顾病史明确是否为症状性颈动脉狭窄;对患者进行1年的随访。 [结果]患者颈动脉狭窄侧的周围脂肪密度比狭窄对侧高4.2%(P＜0.001),且颈动脉周围脂肪密度随狭窄严重程度加重而增加。在狭窄侧,有症状组患者颈动脉周围脂肪密度比无症状组高6.25%(P＝0.015)。在无症状患者中,1年内发生狭窄侧相关脑血管结局事件组颈动脉周围脂肪密度比未发生患者组高12.4%(P＝0.017),Logistic回归分析校正两组差异因素结果仍具有统计学差异(OR＝1.060,95%CI:1.006～1.117,P＝0.028)。 [结论]颈动脉周围脂肪密度与颈动脉狭窄程度呈正相关;症状性颈动脉狭窄以及再发狭窄侧相关缺血性脑血管结局事件患者的颈动脉周围脂肪密度高。     

颈动脉斑块中血管生长因子表达与新生微血管密度的研究

目的 探讨颈动脉斑块中肝细胞生长因子(HGF)及其受体间充质上皮转换因子(MET)mRNA表达与新生微血管密度的相关性。方法 回顾性收集2011年1月～2019年12月郑州大学第一附属医院行颈动脉内膜剥脱术患者32例,根据有无斑块同侧脑缺血症状分为症状组21例和无症状组11例,应用苏木精-伊红染色法及α平滑肌肌动蛋白染色明确2组斑块的病理特点。qRT-PCR法检测2组斑块中HGF mRNA及MET mRNA表达,免疫组织化学染色法检测症状组斑块内新生微血管密度及HGF表达。结果 症状组斑块中血管密度较多,纤维帽较薄,胶原纤维较少。无症状组斑块中血管密度较少,基质较多。qRT-PCR显示,症状组斑块中HGF mRNA及MET mRNA表达明显高于无症状组(0.76±0.02 vs 0.51±0.04,0.68±0.03 vs 0.57±0.03,P<0.01)。免疫组织化学染色显示,颈动脉斑块中HGF和新生血管标志物CD31表达相一致。与无症状组比较,症状组斑块中HGF吸光度值明显增多,差异有统计学意义(P<0.05)。症状组斑块中新生血管密度明显高于无症状组,差异有统计意义...     

颈内动脉外翻内膜剥脱术治疗颈动脉狭窄疗效分析

目的 探讨颈内动脉外翻内膜剥脱术治疗颈动脉狭窄的疗效.方法 对127例颈动脉粥样硬化性狭窄患者行颈内动脉外翻内膜剥脱术,其中有症状者78例,无症状者49例.术后随访5～16个月,回顾性分析其疗效,评价此术式的优点.结果 全组无手术死亡病例.术后患者均复查颈部和脑实质DSA,显示患侧颈动脉形态正常,颈内动脉血管迂曲消失,无1例狭窄.126例患者脑部供血有明显改善,其患侧颈内动脉、皮质下血管显影时间较术前提前0.40～0.90 s,颅内血管血流经过时间缩短0.50～0.80 s;出现脑梗死1例,遗留永久性神经功能缺损,有效率为99.2%,并发症发生率为2.4%.结论 颈内动脉外翻内膜剥脱术是一种有效、安全治疗颈动脉粥样硬化性狭窄的手术方式.     

Increased Internal Carotid Artery Peak Systolic Velocity Is Associated with Presence of Significant Atherosclerotic Plaque Instability Independent of Degree of ICA Stenosis

The aim of our work was to study the relationship between Doppler ultrasound velocity measurements and the presence of histologic features of plaque instability in carotid atherosclerosis, in particular, intraplaque hemorrhage (IPH). Consecutive patients undergoing carotid endarterectomy in a one-year period were included. All patients were examined by duplex ultrasonography and carotid angiography. Endarterectomy specimens were examined histologically for features of plaque instability. The quantity of IPH was measured by digital image analysis. The associations between Peak Systolic Velocity (PSV), end-diastolic velocity (EDV), degree of ICA stenosis, shape and length of the lesion and the features of plaque instability and quantity of IPH were assessed. Seventy-four patients (20 asymptomatic, 54 symptomatic) were included. PSV was independently associated with the presence of significant IPH [p < 0.001, OR = 1.04 (95% CI = 1.01–1.06)], as was the degree of angiographic ICA stenosis [p < 0.05, OR = 0.98 (95% CI = 0.92–1.6)]. Neither EDV nor the shape of the lesion was associated with IPH (p = 0.26 and p = 0.38, respectively). A close correlation was observed between PSV and the quantity of IPH (r² = 0.68, p < 0.0001). A significant association was observed between PSV and the presence of plaque ulceration (p < 0.05); however, this was not found to be independent of the quantity of IPH and the degree of ICA stenosis [p = 0.17, OR = 1.28 (95% CI = 0.6–2.44)]. PSV at the site of ICA stenosis appears to be associated with the quantity of intraplaque hemorrhage, independent of the angiographic degree of ICA stenosis. We propose that the role of Doppler velocity measurements extends beyond measurement of the degree of ICA stenosis. Increased ICA peak systolic velocity by itself may be an indicator of atherosclerotic plaque instability.     

Protected carotid artery stenting in patients with severe stenosis

Intraplaque hemorrhage (IPH) and ulcers are the major findings of unstable plaques. In addition, initial symptoms are associated with postprocedural complications after carotid artery stenting (CAS). The aim of this study was to determine the safety of CAS using an embolic protection device in symptomatic patients with severe carotid artery stenosis and unstable plaques such as IPH and ulcers.This retrospective study included 140 consecutive patients with severe carotid stenosis. These patients underwent preprocedural carotid vessel wall imaging to evaluate the plaque status. We analyzed the incidence of initial clinical symptoms, such as headache, nausea, and vomiting, after CAS. The primary outcomes analyzed were the incidence of stroke, myocardial infarction, and death within 30 days of CAS.Sixty-seven patients (47.9%) had IPH, and 53 (38.9%) had ulcers on carotid wall imaging/angiography. Sixty-three patients (45.0%) had acute neurological symptoms with positive diffusion-weighted image findings. Intraluminal thrombi on initial angiography and flow arrest during CAS were significantly higher in patients with IPH and symptomatic patients. Symptoms were significantly higher in patients with IPH than in those without (63.5% vs 35.1%, P < .001). There were no significant differences in clinical symptoms after stenting or in primary outcomes, regardless of IPH, ulcer, or initial symptoms.IPH and plaque ulceration are risk factors in symptomatic carotid stenosis. However, IPH and plaque ulceration were not a significant risk factors for cerebral embolism during protected carotid artery stent placement in patients with carotid stenosis. Protected CAS might be feasible and safe despite the presence of unstable plaques.     

Carotid Plaque Characteristics Predict Recurrent Ischemic Stroke and TIA: The PARISK (Plaque At RISK) Study

BackgroundPatients with symptomatic carotid stenosis are at high risk for recurrent stroke. The decision for carotid endarterectomy currently mainly relies on degree of stenosis (cutoff value >50% or 70%). Nevertheless, also, patients with mild-to-moderate stenosis still have a considerable recurrent stroke risk. Increasing evidence suggests that carotid plaque composition rather than degree of stenosis determines plaque vulnerability; however, it remains unclear whether this also provides additional information to improve clinical decision making.ObjectivesThe PARISK (Plaque At RISK) study aimed to improve the identification of patients at increased risk of recurrent ischemic stroke using multimodality carotid imaging.MethodsThe authors included 244 patients (71% men; mean age, 68 years) with a recent symptomatic mild-to-moderate carotid stenosis in a prospective multicenter cohort study. Magnetic resonance imaging (carotid and brain) and computed tomography angiography (carotid) were performed at baseline and after 2 years. The clinical endpoint was a recurrent ipsilateral ischemic stroke or transient ischemic attack (TIA). Cox proportional hazards models were used to assess whether intraplaque hemorrhage (IPH), ulceration, proportion of calcifications, and total plaque volume in ipsilateral carotid plaques were associated with the endpoint. Next, the authors investigated the predictive performance of these imaging biomarkers by adding these markers (separately and simultaneously) to the ECST (European Carotid Surgery Trial) risk score.ResultsDuring 5.1 years follow-up, 37 patients reached the clinical endpoint. IPH presence and total plaque volume were associated with recurrent ipsilateral ischemic stroke or TIA (HR: 2.12 [95% CI: 1.02-4.44] for IPH; HR: 1.07 [95% CI: 1.00-1.15] for total plaque volume per 100 µL increase). Ulcerations and proportion of calcifications were not statistically significant determinants. Addition of IPH and total plaque volume to the ECST risk score improved the model performance (C-statistics increased from 0.67 to 0.75-0.78).ConclusionsIPH and total plaque volume are independent risk factors for recurrent ipsilateral ischemic stroke or TIA in patients with mild-to-moderate carotid stenosis. These plaque characteristics improve current decision making. Validation studies to implement plaque characteristics in clinical scoring tools are needed. (PARISK: Validation of Imaging Techniques [PARISK]; NCT01208025)     

Interhemispheric asymmetry in brain perfusion before and after carotid stenting: a 99mTc-HMPAO SPECT study.

PURPOSE: To assess the effect of unilateral carotid angioplasty and stenting (CAS) on cerebral perfusion asymmetry in patients with severe extracranial carotid stenosis by means of technetium Tc 99m hexamethyl-propyleneamine oxime brain single photon emission computed tomography ((99m)Tc-HMPAO SPECT). METHODS: Twenty-nine consecutive patients (22 men; median age 68 years, range 58-80; 13 symptomatic) undergoing unilateral CAS were included in the study. Brain perfusion was assessed by (99m)Tc-HMPAO brain SPECT prior to the procedure and postoperatively at 8 hours and at 2 to 4 months. The asymmetry index (AI), a measure of the interhemispheric asymmetry in perfusion, was calculated as [(counts in "healthy" hemisphere-counts in hemisphere with carotid stenosis)/counts in "healthy" hemisphere]x100. RESULTS: The preoperative AI demonstrated a wide variation (mean -0.5%+/-8.4%, range -19.5% to 14.1%). There was no significant correlation between the degree of carotid stenosis and preoperative AI. The mean preoperative AI in the asymptomatic patients was lower than in the symptomatic group [-4.0%+/-8.5% (range -19.5% to 8.2%) versus 3.8%+/-6.4% (range -5.2% to 14.1%), p=0.01], suggesting reduced perfusion of the ipsilateral cerebral hemisphere compared to the contralateral side in symptomatic patients. AI variation did not improve after CAS; there was no difference in AI among the 3 SPECT studies (p=0.75). Preoperative AI correlated significantly with late AI (r=0.74, p<0.0001); however, there was no statistically significant correlation between immediate postoperative AI and either preoperative (r=0.24, p=0.217) or late (r=0.24, p=0.249) AI. CONCLUSION: Asymmetry in cerebral perfusion in patients with severe extracranial carotid atherosclerosis does not correlate with the degree of carotid stenosis. Symptomatic patients demonstrate compromised perfusion of the ipsilateral hemisphere compared to asymptomatic patients. As judged by (99m)Tc-HMPAO SPECT scanning, cerebral perfusion patterns do not significantly change after CAS.     

CAROTID ENDARTERECTOMY IN SYMPTOMATIC PATIENTS WITH SEVERE INTERNAL CAROTID ARTERY STENOSIS

Several clinical trials have demonstrated that carotid endarterectomy (CE) in symptomatic patients with 70–99% internal carotid artery (ICA) stenosis, when used appropriately in experienced surgical hands (postoperative complications of stroke and death must not exceed 7%) is safe and effective in preventing recurrence of ipsilateral carotid ischemia and, in particular, in preventing disabling ipsilateral stroke. Only five patients need to be treated to prevent one stroke in three years. The time of greatest risk of stroke after the development of symptoms was in the first six months, and the incremental risk decreased out to two years. Instead the risk of stroke with asymptomatic carotid stenosis is low. Forty-five percent of strokes in patients with asymptomatic 60% to 99% stenosis are attributable to lacunes or cardioembolism. Because CE cannot prevent stroke of cardioembolic origin and is less likely to prevent stroke of lacunar origin, it is doubtful that CE can be justified for most patients with asymptomatic arteries.     

Carotid endarterectomy in symptomatic patients with severe internal carotid artery stenosis

Several clinical trials have demonstrated that carotid endarterectomy (CE) in symptomatic patients with 70-99% internal carotid artery (ICA) stenosis, when used appropriately in experienced surgical hands (postoperative complications of stroke and death must not exceed 7%) is safe and effective in preventing recurrence of ipsilateral carotid ischemia and, in particular, in preventing disabling ipsilateral stroke. Only five patients need to be treated to prevent one stroke in three years. The time of greatest risk of stroke after the development of symptoms was in the first six months, and the incremental risk decreased out to two years. Instead the risk of stroke with asymptomatic carotid stenosis is low. Forty-five percent of strokes in patients with asymptomatic 60% to 99% stenosis are attributable to lacunes or cardioembolism. Because CE cannot prevent stroke of cardioembolic origin and is less likely to prevent stroke of lacunar origin, it is doubtful that CE can be justified for most patients with asymptomatic arteries.     

Surgical management of asymptomatic carotid artery stenosis. Authors' experience, problems and prospectives]

BACKGROUND: Some trials have demonstrated effectiveness of carotid endarterectomy (CEA) for preventing stroke in patients with severe symptomatic carotid stenosis. Although some researches, indication to surgery for asymptomatic carotid stenosis is debated up today. Based on personal experience and literature, the main problems of CEA for asymptomatic stenosis are discussed. METHODS: DESIGN: Retrospective study. SETTING: Section of Vascular Surgery, University Department. PATIENTS: CEA was performed in a consecutive series of 63 cases with asymptomatic stenosis (59 patients, 40 males and 19 females, ages ranging from 46 to 80 years, mean 67.9). INTERVENTIONS: CEA was performed under general anesthesia, with primary closure of arteriotomy in 37 cases and patch angioplasty using PTFE in 24, using eversion technique in 2 cases. Pruitt-Inahara shunt was used in 10/63 cases (15.9%), according to the mean velocity of the middle cerebral artery at carotid clamping/mean velocity of the middle cerebral artery pre-clamping ratio x 100 equal to or lesser than 15%, evaluated with transcranial Doppler, or stump pressure lesser than 50 mmHg, when transcranial Doppler examination was not possible. MEASURES: Operative mortality and postoperative morbidity. RESULTS: Operative mortality plus postoperative stroke were 1.6% (1/63). Operative mortality was precisely 0.0%. Postoperative complications were two: one was a neurologic deficit (monoparesis of the arm) and the other was myocardial ischemia. CONCLUSIONS: Four main problems have been shown in CEA for asymptomatic stenosis: 1. Identification of asymptomatic stenosis: 2. Assessment of risk for stroke: 3. Role of CEA: 4. Questions about surgical treatment. For the first problem, it is important to consider possible indicators for carotid stenosis (contralateral carotid stenosis, coronary artery disease, aortic aneurysm, peripheral arterial disease, etc.). With regard to the second problem, it is important to know the natural history of the carotid stenosis, which shows a stroke rate of 1-2% per year. Regarding the third problem, the role of CEA is conditioned by: trials, patient conditions, lesion characteristics and ability of the surgeon. Further studies should identify some groups of patients (with severe carotid stenosis, dyshomogeneous plaque, progression of plaque, etc.), who can profit from CEA. Finally (fourth problem), CEA for asymptomatic carotid stenosis carries all common problems of carotid surgery (preoperative assessment, evaluation of cerebral ischemia due to carotid clamping, shunt, closure of arteriotomy, etc.). Some of these problems can receive ultimate solutions from some studies in next years.     

Karotisstenose

Carotid stenosis is common, especially among patients with vascular risk factors. The usual distinction between “symptomatic” and “asymptomatic” corresponds to older studies on the surgical vs. conservative treatment and to newer studies on interventional treatment (angioplasty with/without stent vs. surgery). However, both forms only describe different stages of activity of the same disease. They are markers of a systemic atherosclerosis, which results in a high risk of cardiovascular events in particular. All patients with carotid stenosis profit from regular clinical and duplexsonographic follow-up-studies of the brain arteries, cardiovascular assessment and good control of all vascular risk factors. Patients with carotid stenosis may profit from carotid intervention, if this takes place shortly after onset of associated cerebral ischemia and/or if there is a favorable benefit-risk ratio.     

Evaluation of cerebral circulation in patients with significant carotid artery stenosis

BACKGROUND: A significant proportion of ischaemic stroke episodes are caused by atherosclerotic lesions in extracranial arteries. Assessment of haemodynamical profile of cerebral arteries in both symptomatic and asymptomatic patients with carotid artery stenosis is of clinical importance. AIM: To assess haemodynamic changes in cerebral arteries in patients with significant internal carotid artery (ICA) stenosis. METHOD: Patients (n=109) were divided into the following groups: group I (GI) - 42 subjects (64.6+/-9.0 years) with asymptomatic ICA stenosis > or =70%; and group II (GII) - 67 subjects (63.4+/-7.1 years) after stroke. The control group consisted of 30 patients (60.3+/-8.9 years) without significant stenoses of extracranial arteries on USG and angiography. In all cases ultrasonographic evaluation of flow velocities and directions in cerebral arteries within the circle of Willis and collateral flow was performed. RESULTS: The severity of ICA stenosis did not differ significantly between GI and GII. Patients in GI had flow velocity in the middle cerebral artery (MCA) increased by 15.7% and by 40.8% in the anterior cerebral artery (ACA) contralateral to the ICA stenosis (p<0.001 and p<0.001), whereas in GII no significant changes in flow velocity in these arteries were observed in comparison with the control group. Patients in the groups I and II had lower flow velocities in MCA ipsilateral to the ICA stenosis, however values for GII patients were significantly lower than in GI patients (p<0.001). The presence of collateral circulation through the anterior and posterior communicating arteries (ACoA and PCoA) was similar in GI and GII; however, the flow velocities in the ipsilateral MCA and ACA were significantly higher in asymptomatic patients (GI). The frequency of active collateral circulation through both ACoA and PCoA increased along with the increase of ICA stenosis severity (p=0.003; p<0.001). CONCLUSIONS: Collateral flow in the circle of Willis in subjects with ICA stenosis occurs equally often in symptomatic and asymptomatic patients; however, it is more efficient in patients without symptoms. The rate of development of collateral circulation depends on ICA stenosis severity. The important role in maintaining collaterals within the circle of Willis is played by ACoA, although in some patients MCA may also be supplied by PCoA.