短暂性脑缺血发作患者的认知功能及脑血流改变

目的　探讨短暂性脑缺血发作 (TIA)患者的认知功能与脑血流改变及两者之间的关系。方法应用事件相关电位 (ERP)、老年认知功能量表 (SECF)、磁共振血管成像 (MRA) ,对 35例TIA患者进行检测评估 ,并将ERP及SECF检测结果与性别、年龄、利手和文化程度方面严格匹配的 33名健康对照者进行对比。结果　与对照组相比 ,TIA患者的P3 潜伏期明显延长 (P <0 0 5 ) ;有明显的记忆障碍 ,注意力、注意集中能力、信息提取能力均下降 ;TIA组 94 2 8%有脑动脉狭窄和闭塞。结论　TIA患者有多项认知功能障碍 ,尤以记忆损害突出 ;有持久的脑血流低灌注 ,认知功能损害与此密切相关     

Cerebral blood flow and CO2 reactivity in transient ischemic attacks: comparison between TIAs due to the ICA occlusion and ICA mild stenosis

Hemispheric mean cerebral blood flow (CBF), together with its CO2 reactivity in response to hyperventilation, was investigated in 18 patients with transient ischemic attacks (TIAs) by intraarterial 133Xe injection method in a subacute-chronic stage of the clinical course. In 8 patients, the lesion responsible for symptoms was regarded as unilateral internal carotid artery (ICA) occlusion, and in 10 patients, it was regarded as unilateral ICA mild stenosis (less than 50% stenosis in diameter). Resting flow values were significantly (P less than 0.05) decreased in the affected hemisphere of TIA due to the ICA occlusion as compared with the unaffected hemisphere of the same patient, regarded as the relative control. It was not decreased in the affected hemisphere of TIA due to the ICA mild stenosis as compared with the control. With respect to the responsiveness of CBF to changes in PaCO2, it was preserved in both TIAs, due to the ICA occlusion and ICA mild stenosis. Vasoparalysis was not observed in either types of TIAs in the subacute-chronic stage. However, in the relationship of blood pressure and CO2 reactivity, expressed as delta CBF(%)/delta PaCO2, pressure-dependent CO2 reactivity as a group was observed with significance (P less than 0.05) in 8 cases of TIA due to the ICA occlusion, while no such relationship was noted in 10 cases of TIA due to the ICA mild stenosis. Moreover, clinical features were different between TIAs due to the ICA occlusion and ICA mild stenosis, i.e., more typical, repeatable TIA (6.3 +/- 3.7 times) with shorter duration (less than 30 minutes) was observed in TIAs due to the ICA mild stenosis, while more prolonged, less repeatable TIA (2.4 +/- 1.4 times) was observed in TIAs due to fixed obstruction of the ICA. From these observations, two different possible mechanisms as to the pathogenesis of TIA might be expected, e.g., TIA of microembolic origin due to the ICA mild stenosis, and TIA of hemodynamic origin due to fixed obstruction of the ICA, for whom the bypass surgery might be beneficial, i.e., all TIAs are not based on the same mechanism.     

Cerebral blood flow and cerebrovascular CO2 reactivity in stroke-age normal controls

We used the noninvasive 133-xenon inhalation technique to determine cerebral hemodynamics in 55 normal volunteers aged 18 to 88. Values for cerebral blood flow and cerebrovascular CO2 reactivity in fast-clearing tissue (flow gray) and slow-clearing tissue (flow white) were examined as functions of age and in relation to hematocrit, blood pressure, and evidence of extracranial vascular disease. Flow gray declined linearly with age, but no corresponding change was found in flow white or in CO2 reactivity. The data suggest that the progressive fall in flow gray is due to a physiologic aging process.     

Cerebral blood flow distribution and reactivity during the symptom-free stages of transient ischemic attacks--a 99mTc-HMPAO SPECT study]

Even during the symptom-free stages, patients with transient ischemic attacks (TIA) often show cerebral blood flow (CBF) disturbances. For evaluating the factors which cause these abnormalities, we studied CBF and CBF reactivity to acetazolamide (Diamox) using a 99mTc-hexamethylpropyleneamine oxime (HMPAO) single photon emission computed tomography (SPECT). The results from CBF-SPECT were compared with X-ray computed tomography (CT), cerebral arteriogram, clinical characteristics of TIA and cerebrovascular risk factors. The overall sensitivity rates in detecting the lesion were 68% in CBF-SPECT and 9% in CT. The size of the hypoperfused area tended to be wide in patients who had intracranial, severe stenotic or multiple arterial lesions on the ipsilateral side. No such relations were found between CBF and other examinations. Brain hypoperfusion was located in the subcortical region in eight patients; two patients showed a small hypodense lesion on CT which corresponded to the hypoperfusion on SPECT, and three patients showed no arteriographic abnormality. Hypoperfusion in the cortex was seen in seven patients; all patients showed arteriographic abnormality, but no CT abnormality. The severity rating of the vascular stenosis and hypoperfusion, and the incidence of the intracranial lesions were higher in this group than the group with subcotical hypoperfusion. Seven patients showed fixed normoperfusion before and after diamox injection. Two patients with a subcortical small infarction showed fixed hypoperfusion even after diamox injection. Twelve patients showed focal hypoperfusion before diamox with a new filling-in after diamox. Only one patient showed resting hypoperfusion and decreased CBF reactivity to diamox.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cerebral infarct in apparent transient ischemic attack

Fifty-seven patients with transient ischemic attacks in the carotid territory had CTs 3 to 28 days after the last episode. Sixteen (28%) showed an infarct appropriate to the symptoms. Infarcts were more likely with longer mean duration of attacks, longer duration of the longest attack, longer total duration of symptoms, and smaller number of attacks. Age, sex, type and extent of hemisphere symptoms, and vascular risk factors had no influence. If attacks lasted more than 45 to 60 minutes, the risk of infarction was more than 80%; most were actually infarcts. So-called TIAs included two subgroups, true TIA and CITS (cerebral infarction with transient signs), which corresponded respectively to a short (mean, 21 minutes) or long (mean, 6 hours) duration of attack.     

SPECT study of cerebral blood flow reactivity after acetazolamide in patients with transient ischemic attacks

We investigated 15 patients with one or more transient ischemic attacks (TIAs) in the internal carotid artery territory within the month following the most recent TIA. Cerebral blood flow (CBF) was measured by single-photon emission computed tomography, using intravenous xenon-133 before and after injection of 1 g acetazolamide. Six patients had severe carotid stenosis or occlusion; the other nine patients had no significant carotid lesions. Twenty age-matched volunteers free of neurologic symptoms or history were used as controls. Mean CBF in the sylvian region was not significantly different between patients and controls. Seven patients exhibited a focal hypoperfusion at rest in the symptomatic hemisphere, and their hypoperfused areas were hyporeactive after administration of acetazolamide. Seven other patients exhibited hyporeactive areas after acetazolamide administration while their CBF tomograms at rest were normal. Thus, CBF abnormalities were detected in 14 of the 15 patients. Our findings suggest that CBF measured early after acetazolamide administration could be useful to confirm the clinical diagnosis of TIA. In the nine patients with no significant lesion of the internal carotid artery, the areas of hypoperfusion were small and were probably related to the focal ischemic event. In the six patients with severe lesions of the internal carotid artery, abnormalities were of variable size and intensity but were often large and pronounced. The discrepancy between these two subgroups of patients could be ascribed to the hemodynamic influence of the internal carotid artery lesions. Moreover, our findings may provide some insight into the pathophysiology of TIAs.     

Local cerebral blood flow and its CO2 reactivity in the ischemic cerebrovascular diseases before and after bypass]

We evaluated the effects of the STA-MCA anastomosis on local cerebral blood flow (LCBF) and CO2 cerebrovascular reactivity (CVR) in ischemic cerebrovascular diseases (CVD). [Patients and Methods] We examined the LCBF and CVR of 21 patients with ischemic CVD subjected standard STA-MCA anastomosis. During surgery, LCBF was continuously measured using the thermal diffusion method sometimes in a state of decreased PaCO2 (median: 7.2mmHg) before and after bypass. CVR was represented as % delta LCBF/delta CO2. [Results] 1) In the control group (with non-ruptured aneurysm, n = 7), LCBF was 58.6 +/- 14.1 ml/100g/min and % delta LCBF/delta CO2 was 4.68 +/- 1.68%/mmHg. 2) Before bypass, LCBF was 46.7 +/- 10.3ml/100g/min. It was significantly (p < 0.05) lower than control level. After bypass, LCBF increased significantly (p < 0.05) to 62.0 +/- 14.3 ml/100g/min. 3) Before bypass, % delta LCBF/delta CO2 was -1.36 +/- 4.34%/mmHg. In the 14 cases (66.7%), % delta LCBF/delta CO2 was below the 0%/mmHg (inverse steal effect). 4) After bypass, it increased to 0.08 +/- 2.73%/mmHg. 11 cases (52.4%) showed % delta LCBF/delta CO2 was above the 0%/mmHg. 5) In the group with a preoperative % delta LCBF/delta CO2 of less than 0%/mmHg, preoperative LCBF was 43.6 +/- 9.3 ml/100g/min, which was significantly low (p < 0.01) compared to that in the group with higher % delta LCBF/delta CO2. After bypass, LCBF and % delta LCBF/delta CO2 remarkably increased in the group with % delta LCBF/delta CO2 below 0%/mmHg. [Conclusion] Before bypass, LCBF was low and CVR was severely disturbed. In the 14 cases % delta LCBF/delta CO2 was below 0%/mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)     

TIA患者脑动脉微栓子的监测及其与颈动脉斑块的相关性

目的 监测短暂性脑缺血发作(TIA)患者脑动脉微栓子(MES)的出现率,探讨其与颈动脉斑块的相关性.方法 112例TIA患者均进行MES的监测和颈动脉彩色多普勒超声检测,分别观察MES阳性与有颈动脉斑块的病例数.结果 (1)MES阳性者31例,阳性率27.68%.有颈动脉斑块者67例,斑块出现率59.82%,其中不稳定斑块28例,占有斑块病例的41.79%.(2)67例有斑块者MES阳性率35.82%,较45例无斑块者15.56%高(P<0.05);28例不稳定斑块者MES阳性率57.14%,较39例稳定斑块者20.51%高(P<0.01).(3)MES与斑块的大小、部位和个数无相关性.结论 颈动脉不稳定斑块的脱落是TIA患者脑动脉MES的主要来源之一,稳定颈动脉斑块的处理是减少TIA复发及其后出现脑梗死的重要举措.

Abstract：

Objective To study the prevalence of cerebral microembolism(MES)in patients with TIA and its relation to carotid plaque.Methods Total 112 patients with TIA were studied.The cerebral artery MES were monitored by TCD.and carotid plaques were detected by color transcranial Doppler.The cases with cerebral artery MES and with carotid plaques were respectively recorded.Results There were 31 patients with MES and the prevalence WaS 27.68%.There were 67 patients with carotid plaques and the presence was 59.82%;among them,28 patients with unstable carotid plaques constituted 41.79%.The prevalence of MES in 67 patients with carotid plaques(35.82%)Was significantly hisher than 45 patients without carotid plaques(15.56%)(P<0.05),while the prevalence of MES in 28 patients with unstable carotid plaques(57.14%)was greatly higher than 39 patients with stable carotid plaques(20.51%)(P<0.01).The prevalence of MES had nothing to do with the size,position and quantity of the carotid plaque.Conclusions The desquamation of unstable carotid plaque is one of the main sources of cerebral artery MES.The stabilization of carotid plaque is an important measure to reduce relapse of TIA and prevent the patient from cerebral infarction after TIA.     

短暂性脑缺血发作的眩晕及脑血流改变

目的探讨短暂性脑缺血发作(TIA)患者的眩晕症状与脑血流改变。方法回顾性分析136例患者的临床资料,对颈内动脉系统TIA及椎基底动脉系统TIA(VB-TIA)的眩晕症状进行对比,应用磁共振血管成像(MRA)、TCD检查分析脑血流的改变。结果VB-TIA是颈内动脉系统TIA的3倍,占总发病率75%,VB-TIA患者的眩晕症状占90.2%。136例TIA并眩晕症状105例,占77.2%。TCD、MRA检查脑血流异常分别为91%、85%。结论TIA患者眩晕症状突出,TCD、MRA检查在TIA的诊断中对脑血流改变提供有价值的客观依据,说明脑动脉硬化及狭窄加之颈椎病的发生,最终导致持久的脑血流低灌注,即慢性脑供血不足。TIA的眩晕症状与颈椎病、脑血流关系密切。     

Abnormalities on diffusion-weighted magnetic resonance imaging in patients with transient ischemic attack]

We studied abnormalities on diffusion-weighted magnetic resonance imaging (DWI) in patients with transient ischemic attack (TIA). Out of 18 consecutive TIA patients, 9 patients had relevant focal abnormalities on DWI. Among TIA patients, six patients were associated with atrial fibrillation (Af), and all of these patients had focal abnormalities on DWI as well. TIA patients with Af had significantly more frequent focal abnormalities on DWI than those without Af (p = 0.009; Fisher's exact probability test). In addition, the duration of TIA symptoms was not related to the presence of focal abnormalities on DWI. These results indicate that embolic mechanism may cause focal abnormalities on DWI. DWI was more sensitive to detect responsible ischemic lesions in these patients than T2-weighted image or fluid-attenuated inversion recovery image.     

Magnetic resonance imaging in patients with transient ischemic attack

<正>Transient ischemic attack(TIA)is a temporary event,which portends a higher risk of a disabling stroke following the TIA.However,the evaluation and management of TIA vary worldwide and is debated and controversial.With the development of brain imaging,particularly diffusion weighted imaging-magnetic resonance imaging(DWI-MRI),the diagnosis of TIA changed from time-based definition to a tissue-based one.DWI-MRI became a mandatory tool in the TIA workup.The DWI-MRI provides not only the evidence to distinguish between TIA and acute ischemic stroke,furthermore it predicts TIA patients who are at higher risk of disabling stroke,which can be prevented by an immediate evaluation and treatment of TIA.     

Survey of blood pressure control status in patients with ischemic stroke or transient ischemic attack in China

OBJECTIVE: We sought to assess the current status of blood pressure control and the use of antihypertensive drugs in patients with ischemic stroke (IS) or transient ischemic attack (TIA) in China. SUBJECTS AND METHODS: A cross-sectional study (across 19 urban outpatient clinics) on secondary stroke prevention measures was conducted. All subjects diagnosed with IS or TIA at neurological clinics were enrolled consecutively. Face to face interviews were conducted by a trained neurologist and research assistant using questionnaire at the same day of enrollment. RESULTS: A total of 2283 IS or TIA patients were included in the survey. A history of hypertension was present in 1509 patients, of which 896 (59.4%) had uncontrolled blood pressure. A history of hypertension was absent in 603 patients, of whom 162 (26.9%) had uncontrolled blood pressure. In addition, 495 (88.9%) of patients with diabetes mellitus had uncontrolled blood pressure (systolic blood pressure > or = 130 mmHg or diastolic blood pressure > or = 80 mmHg). In multivariate logistic regression analysis, having monthly income of > 1000 yuan [odds ratio (OR): 2.040; 95% confidence interval (CI): 1.277-3.259), female (OR: 1.546; 95% CI: 1.174-2.034) and smoking habits (OR: 1.428; 95% CI: 1.014-2.013) remained significantly associated with blood pressure control. In contrast, compound preparation (OR: 0.685; 95% CI: 0.473-0.993) was inversely associated with the likelihood of blood pressure control. CONCLUSION: Blood pressure control rate among IS or TIA patients in major metropolitan clinics is an important issue in China which might largely influence the efforts in stroke prevention and treatment. Further works are needed to develop substantive quality improvement strategies of stroke secondary prevention care.     

Cerebral infarction in patients with transient ischemic attacks

Summary Cranial computed tomography of 284 patients with transient ischemic attacks (TIAs) and without previous stroke was evaluated. The sample population included patients with carotid and/or vertebrobasilar TIAs. Computed tomography revealed cerebral infarction in 34 patients, including 5 with multiple infarctions. The lesion location was consistent with TIA symptoms in 16 patients. In another 16 patients, however, the lesion location did not correspond to the TIA symptoms; these lesions were attributed to previous silent infarctions. Two patients with multiple infarctions had both symptomatic and asymptomatic lesions. Age and carotid stenosis were each significantly related to an increased chance of detecting cerebral infarction (either symptomatic or asymptomatic). No significant relationship between race, gender, hypertension, diabetes, cardiac disease, or smoking and the incidence of infarction was found by either univariate or multivariate analyses.     

不同剂量阿托伐他汀对短暂性脑缺血发作转归的影响

目的：观察阿托伐他汀对短暂性脑缺血发作（T IA ）患者转归的影响。方法130例T IA患者随机分为高剂量（40 mg/d）阿托伐他汀治疗组（H组）和低剂量（10 mg/d）阿托伐他汀治疗组（L组）各65例,2组患者均给予相同的基础治疗。观察2组患者住院及随诊1 a期间T IA复发及形成梗死、新发冠脉事件、脑出血及死亡情况,并比较2组1 a点LDL水平。结果住院期间和随访期间,H组TIA复发率、梗死及新发冠脉事件发生率及LDL水平明显低于L组。结论高剂量（40 mg/d）阿托伐他汀能显著改善短暂性脑缺血患者的发作,值得临床推广。     

血脂康对短暂性脑缺血发作患者颈动脉粥样硬化斑块和血脂的影响

目的探讨血脂康对短暂性脑缺血发作(TIA)患者颈动脉粥样硬化斑块和血脂水平的影响。方法65例有颈动脉粥样硬化斑块的TIA患者随机分为血脂康组和对照组;血脂康组口服血脂康及阿司匹林6个月,对照组仅口服阿司匹林。治疗前后进行颈动脉超声检查,观察颈动脉内中膜厚度(IMT)、粥样硬化斑块面积;检测血脂、血清一氧化氮(NO)及氧化低密度脂蛋白(oxLDL)浓度,比较治疗6个月内两组患者脑血管事件的发生率。结果治疗后,血脂康组血胆固醇、低密度脂蛋白、三酰甘油和oxLDL水平比治疗前明显下降,NO和高密度脂蛋白水平明显升高(均P<0.01);颈动脉IMT变薄及斑块面积减少,与对照组比较差异均有显著性(P<0.05～0.01)。血脂康组脑血管事件的发生率为9.7%,对照组为20.6%,两组间差异无显著性(P>0.05)。结论血脂康不仅有调整血脂的作用,还具有抗脂质氧化、保护血管内皮等多种作用,并能消除或稳定TIA患者的颈动脉粥样硬化斑块。