Statin Use is Independently Associated with Smaller Infarct Volume in Nonlacunar MCA Territory Stroke

BACKGROUND: Studies have shown an association between HMG-CoA reductase inhibitors (statins) and improved stroke outcomes, possibly secondary to neuroprotective properties. OBJECTIVE: To assess whether patients taking statins prior to ischemic stroke have smaller infarcts on magnetic resonance imaging (MRI), adjusting for other relevant clinical factors. DESIGN: We retrospectively reviewed the Cleveland Clinic Foundation (CCF) Neurology Inpatient Database from June 2002 through June 2004. Demographics, medications, stroke subtype, diffusion-weighted imaging (DWI) infarct volume, admission NIHSS, and hours to MRI were collected. Patients with a nonlacunar middle cerebral artery (MCA) territory infarct and MRI less than 48 hours from symptom onset were included (n= 143). A multivariable linear regression model was constructed to determine independent predictors of smaller infarct volume. RESULTS: A total of 143 patients were studied, including 38 patients taking statins at the time of their stroke. In univariate analysis, patients using statins were significantly more likely to have a history of hyperlipidemia, atrial fibrillation, and coronary artery disease and to be using coumadin, antiplatelet drugs, and angiotensin-converting enzyme inhibitors. Patients on statins had a tendency toward smaller infarcts in univariate analysis (median 25.4 cm(3) vs. 15.5 cm(3), P= 0.054). In multivariable linear regression analysis statin use, patient age, and TIA within the prior 4 weeks were independently associated with smaller DWI volumes; vessel occlusion on vascular imaging, and cardioembolic stroke subtype with larger infarct size. CONCLUSIONS: Statin use prior to the onset of nonlacunar MCA infarction was associated with a smaller infarct volume independent of other factors. Further studies utilizing both clinical and radiologic outcomes will be required to confirm these findings.     

Association of higher serum calcium levels with smaller infarct volumes in acute ischemic stroke

BACKGROUND: Elevated serum calcium levels at admission in patients with stroke have been associated with less severe clinical deficits and with better outcomes; however, the relationship between serum calcium levels and volumetric measurement of cerebral infarct size on neuroimaging has not been studied, to our knowledge. OBJECTIVE: To assess the relationship between serum calcium levels at admission and initial diffusion-weighted magnetic resonance imaging (DWI) infarct volumes among patients with acute ischemic stroke. DESIGN: Secondary analysis of prospectively collected hospital quality improvement data. SETTING: Tertiary university hospital. PATIENTS: One hundred seventy-three consecutive patients with acute ischemic stroke initially seen within 24 hours of the last known well time. MAIN OUTCOME MEASURES: Total serum calcium levels were measured on admission and were collapsed into quartiles. The DWI lesions were outlined using a semiautomated threshold technique. The relationship between serum calcium level quartiles and DWI infarct volumes was examined using multivariate quartile regression analysis. RESULTS: One hundred seventy-three patients (mean age, 70.3 years [age range, 24-100 years]; median National Institutes of Health Stroke Scale score, 4 [range, 0-38]) met the study criteria. The median DWI infarct volumes for the serum calcium level quartiles (lowest to highest quartile) were 9.42, 2.11, 1.03, and 3.68 mL. The median DWI infarct volume in the lowest serum calcium level quartile was larger than that in the other 3 quartiles (P < .005). After multivariate analysis, the median adjusted DWI infarct volumes for the serum calcium level quartiles (lowest to highest) were 8.9, 5.8, 4.5, and 3.8 mL. The median adjusted DWI infarct volume in the lowest serum calcium level quartile was statistically significantly larger than that in the other 3 quartiles (P < .05). CONCLUSIONS: Higher serum calcium levels at admission are associated with smaller cerebral infarct volumes among patients with acute ischemic stroke. These results suggest that serum calcium level may serve as a clinical prognosticator following stroke and may be a potential therapeutic target for improving stroke outcome.     

Diffusion MRI in patients with transient ischemic attacks.

BACKGROUND AND PURPOSE: Diffusion MRI has established value in patients with ischemic stroke but has not been systematically investigated in patients with transient ischemic attack (TIA). METHODS: Clinical, conventional MRI, and diffusion MRI data were collected on 42 consecutive patients with symptoms of cerebral TIA. TIA imaging data were compared with those from a contemporaneous group of 23 completed stroke patients. RESULTS: Twenty of the 42 TIA patients (48%) demonstrated neuroanatomically relevant focal abnormalities on diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) imaging. When present, DWI/ADC signal changes in TIA patients were less pronounced and smaller in volume than those in completed stroke patients. TIA symptom duration was significantly longer for DWI-positive than for DWI-negative patients, 7.3 versus 3.2 hours. Diffusion MRI information changed the suspected anatomic and vascular TIA localization and the suspected etiologic mechanism in over one third of patients with diffusion MRI abnormalities. Of the 20 TIA patients with identifiable lesions on diffusion MRI, 9 had follow-up imaging studies; of these, 4 did not show a relevant infarct on follow-up imaging. CONCLUSIONS: Diffusion MRI demonstrates ischemic abnormalities in nearly half of clinically defined TIA patients. The percentage of patients with a DWI lesion increases with increasing total symptom duration. In nearly half, the diffusion MRI changes may be fully reversible, while in the remainder the diffusion MRI findings herald the development of a parenchymal infarct despite transient clinical symptoms. Finally, diffusion imaging results have significant clinical utility, frequently changing the presumed localization and etiologic mechanism.     

Management and outcome of patients with transient ischemic attack admitted to a stroke unit

BACKGROUND: The way in which patients with transient ischemic attack (TIA) are investigated and treated varies substantially worldwide. There are no data on the management and outcome of TIA patients admitted to a stroke unit. We assessed to what extent rapid management of TIA patients admitted to a stroke unit led to specific treatments which can prevent stroke and evaluated the early risk and predictors of stroke in these patients. METHODS: From January 2003 to November 2005, 203 consecutive patients with a recent (<48 h) TIA were admitted to our stroke unit. All patients had a diffusion-weighted imaging (DWI) on admission, a standardized etiological workup, and were followed up to 3 months. RESULTS: The median (interquartile range) time from TIA onset to admission to the stroke unit was 12 h (5-25). DWI revealed acute lesions in 64 patients (32%). Of the 203 patients, 147 (72%) were treated by antiplatelet therapy and 56 (28%) with high doses of heparin, soon after their admission. In addition, 7 patients (3%) had a carotid revascularization. The risk of stroke was 2.5% (95% CI, 0.3-4.7) at 1 week, and 3.5% (1.0-6.1) at 3 months. In multivariate analysis, a score > or =5 at the previously validated ABCD score (HR = 5.0; 1.0-25.8; p = 0.06) and the presence of DWI abnormalities (HR = 10.3; 1.2-86.7; p = 0.03) were independent predictors of stroke at 3 months. CONCLUSION: Early management of TIA in a stroke unit leads to specific treatments in a significant proportion of cases. The presence of acute lesions on DWI and the ABCD score predict the 3-month risk of stroke after TIA.     

Preoperative antithrombotic treatment in acutely symptomatic carotid artery stenosis

ObjectivesEarly recurrence of cerebral ischemia in acutely symptomatic carotid artery stenosis can precede revascularization. The optimal antithrombotic regimen for this high-risk population is not well established. Although antiplatelet agents are commonly used, there is limited evidence for the use of anticoagulants. We sought to understand the safety and efficacy of short-term preoperative anticoagulants in secondary prevention of recurrent cerebral ischemic events from acutely symptomatic carotid stenosis in patients awaiting carotid endarterectomy (CEA).Materials and MethodsA retrospective query of a prospective single institution registry of carotid revascularization was performed. Patients who presented with acute ischemic stroke or transient ischemic attack (TIA) attributable to an ipsilateral internal carotid artery stenosis (ICA) were included. Antiplatelet (AP) only and anticoagulation (AC) treatment arms were compared. The primary outcome was a composite of preoperative recurrent ischemic stroke or TIA. The primary safety outcome was symptomatic intracranial hemorrhage.ResultsOut of 443 CEA patients, 342 were in the AC group and 101 in the AP group. Baseline characteristics between groups (AC vs AP) were similar apart from age (71±10.5 vs 73±9.5, p=0.04), premorbid modified Rankin scale (mRS) score (1.0±1.2 vs 1.4±1.3, p=0.03) and stroke as presenting symptom (65.8 vs 53.5%, p=0.02). Patients in the AC group had a lower incidence of recurrent stroke/TIA (3.8 vs 10.9%, p=0.006). One patient had symptomatic intracranial hemorrhage in the AC group, and none in the AP group. In multivariate analysis controlling for age, premorbid mRS, stroke severity, degree of stenosis, presence of intraluminal thrombus (ILT) and time to surgery, AC was protective (OR 0.30, p=0.007). This effect persisted in the cohort exclusively without ILT (OR 0.23, p=0.002).ConclusionsShort term preoperative anticoagulation in patients with acutely symptomatic carotid stenosis appears safe and effective compared to antiplatelet agents alone in the prevention of recurrent cerebral ischemic events while awaiting CEA.     

Differential patterns of evolution in acute middle cerebral artery infarction with perfusion-diffusion mismatch: atherosclerotic vs. cardioembolic occlusion

BACKGROUND: An acute perfusion-diffusion mismatch is known to be the strongest predictor of infarct growth. However, the differential patterns of clinical and radiological evolution according to stroke mechanism are unknown. METHODS: The study retrospectively reviewed consecutive patients who had 1) acute middle cerebral artery (MCA) territory infarction, 2) diffusion- and perfusion-weighted imaging (DWI and PWI) and MR angiography within 24 h of onset, and follow-up DWI 5 days later, 3) stenosis (>/=50%) or occlusion of MCA on baseline imaging, 4) a baseline PWI-DWI mismatch >20%, and 5) either atherosclerotic MCA disease (MCAD) or cardioembolism (CE). National Institutes of Health Stroke Scale (NIHSS) scores and infarct volume at baseline and 5 days were obtained. RESULTS: Of 90 patients, 52 had MCAD and 38 had CE. At baseline, CE group had more severe stroke (median NIHSS, 9 vs. 5; p=0.001) and larger infarct volume (median 8.32 cc vs. 3.0 cc; p=0.034) than MCAD group. During the 1-week period, CE group had larger infarct volume growth (median 12.85 cc vs. 3.02 cc; p=0.004) than MCAD group, although clinical improvement based on NIHSS (baseline minus 5-day) tended to be higher for CE than MCAD group (median 3 vs. 1; p=0.08). The correlation between infarct volume and NIHSS score was stronger in CE (r=0.841) compared to MCAD (r=0.582) group at 5-day. CONCLUSIONS: Substantial differences in the clinico-radiological evolution of acute ischemic stroke exist according to stroke mechanism. These data emphasize the importance of the stroke mechanism in the design of MRI-based acute stroke trials.     

Clinical determinants of infarct pattern subtypes in large vessel atherosclerotic stroke

Abstract Background   Although stroke from large vessel atherothromboembolism has a common pathogenesis, its topographic presentation is variable. Given the impact of cerebral infarct size and location on incident stroke magnitude and subsequent prognosis, we evaluated the determinants of cerebral infarct topography among patients with atherosclerotic stroke. Methods   We analyzed data on 148 consecutive patients admitted over a 4-year period to a university medical center with acute ischemic stroke within the MCA distribution on DWI, presumed due to atherosclerosis. Based on the DWI data, we divided the patients into three stroke phenotypes: large cortical, small (< 1 cm in diameter) cortical, and deep pattern. Independent factors for each stroke phenotype were evaluated using logistic regression. Results   After adjusting for covariates, premorbid statin use (OR, 3.05; 95 % CI, 1.40–6.65) and older age (OR, 1.05 per 1 year increase; 95 % CI, 1.02–1.08) were independently associated with the small cortical phenotypic pattern. In contrast, younger age (OR, 0.95 per 1 year increase; 95 % CI, 0.92–0.98), premorbid statin non-use (OR, 0.40; 95 % CI, 0.17–0.99), and higher levels of fasting s-glucose (OR, 1.01 per 1 mg/dl increase; 95 % CI, 1.00–1.02) and admission peripheral WBC counts (OR, 1.13 per 1 × 10⁹ cells/L; 95 % CI, 1.00–1.27) were independently associated with the large cortical pattern. There was no relation between DWI patterns and LDL-cholesterol levels. Conclusions   Age, premorbid statin use, s-glucose and WBC count predict atherosclerotic stroke phenotype. Further studies should examine whether modifying some of these factors may result in more favorable phenotypic patterns. Electronic Supplementary Material  The online version of this article (DOI) contains supplementary material, which is available to authorized users.     

Combined diffusion and perfusion MRI with correlation to single-photon emission CT in acute ischemic stroke. Ischemic penumbra predicts infarct growth.

BACKGROUND AND PURPOSE: More effective imaging methods are needed to overcome the limitations of CT in the investigation of treatments for acute ischemic stroke. Diffusion-weighted MRI (DWI) is sensitive in detecting infarcted brain tissue, whereas perfusion-weighted MRI (PWI) can detect brain perfusion in the same imaging session. Combining these methods may help in identifying the ischemic penumbra, which is an important concept in the hemodynamics of acute stroke. The purpose of this study was to determine whether combined DWI and PWI in acute (<24 hours) ischemic stroke can predict infarct growth and final size. METHODS: Forty-six patients with acute ischemic stroke underwent DWI and PWI on days 1, 2, and 8. No patient received thrombolysis. Twenty-three patients underwent single-photon emission CT in the acute phase. Lesion volumes were measured from DWI, SPECT, and maps of relative cerebral blood flow calculated from PWI. RESULTS: The mean volume of infarcted tissue detected by DWI increased from 46.1 to 75.6 cm(3) between days 1 and 2 (P<0.001; n=46) and to 78.5 cm(3) after 1 week (P<0.001; n=42). The perfusion-diffusion mismatch correlated with infarct growth (r=0. 699, P<0.001). The volume of hypoperfusion on the initial PWI correlated with final infarct size (r=0.827, P<0.001). The hypoperfusion volumes detected by PWI and SPECT correlated significantly (r=0.824, P<0.001). CONCLUSIONS: Combined DWI and PWI can predict infarct enlargement in acute stroke. PWI can detect hypoperfused brain tissue in good agreement with SPECT in acute stroke.     

Transient ischemic attack with infarction: A unique syndrome?

It is debated whether transient symptoms associated with infarction (TSI) are best considered a minor ischemic stroke, a subtype of transient ischemic attack (TIA), or a separate ischemic brain syndrome. We studied clinical and imaging features to establish similarities and differences among ischemic stroke, TIA without infarction, and TSI. Eighty-seven consecutive patients with TIA and 74 patients with ischemic stroke were studied. All underwent diffusion-weighted imaging on admission. Symptom duration and infarct volume were determined in each group. Thirty-six patients (41.3%) with TIA had acute infarct(s). Although TIA-related infarcts were smaller than those associated with ischemic stroke (mean, 0.7 vs 27.3 ml; p < 0.001), there was no lesion size threshold that distinguished ischemic stroke from TSI. In contrast, the symptom duration probability density curve was not broad, but instead peaked early with only a few patients having symptoms for longer than 200 minutes. The probability density function for symptom duration was similar between TIA with or without infarction. The in-hospital recurrent ischemic stroke and TIA rate was 19.4% in patients with TSI and 1.3% in those with ischemic stroke. TIA with infarction appears to have unique features separate from TIA without infarction and ischemic stroke. We propose identifying TSI as a separate clinical syndrome with distinct prognostic features.     

A Therapeutic International Normalized Ratio Results in Smaller Infarcts and Better Outcomes for Patients with Ischemic Stroke

Background: Prior studies have shown that warfarin is effective for both primary and secondary stroke prevention in individuals with atrial fibrillation. It is also known that those on warfarin with atrial fibrillation often have poorer long-term poststroke outcomes, possibly because cardioembolic strokes tend to be larger and more severe. Less is known regarding the direct effect of the international normalized ratio (INR) value at the time of stroke on severity or long-term functional status. Methods: We prospectively followed a consecutive series of 112 patients presenting to our institution with acute ischemic stroke between 2013 and 2018 who were on warfarin. Along with INR on admission, data were collected regarding patient demographics, vascular risk factors, stroke characteristics, and functional outcomes. Patients were stratified by INR into “therapeutic” and “subtherapeutic” groups. Stroke severity (NIH Stroke Scale), infarct volume, and outcome (modified Rankin Scale) were assessed on admission, discharge, and follow-up (3 months poststroke). Differences were calculated using Student's t-tests and regression analyses. Results: The average INR on admission was 1.6 for the entire cohort. Seventy six percent were subtherapeutic on admission (INR < 2.0). Therapeutic patients had lower National Institutes of Health Stroke Scale scores on admission (5.9 versus 9.5, P = .033), significantly smaller stroke volumes (19.5 cc versus 49.2 cc, P = .036), and were more likely to show more than 1 digit improvement on follow-up mRS than subtherapeutic patients. Conclusions: Stroke size and severity is significantly reduced in patients with ischemic strokes who present therapeutic on warfarin. The greater volume of brain saved may ultimately lead to better functional recovery.     

Symptomatic intracranial atherosclerosis: outcome of patients who fail antithrombotic therapy

OBJECTIVE: To determine the prognosis of patients with symptomatic intracranial atherosclerosis who fail antithrombotic therapy. BACKGROUND: The outcome of patients with symptomatic intracranial atherosclerosis who fail antithrombotic therapy is unknown. These patients may represent the target group for investigation of more aggressive therapies such as intracranial angioplasty. METHODS: The authors performed a chart review and telephone interview of patients with symptomatic intracranial atherosclerosis identified in the Stanford Stroke Center clinical database. A Cox regression model was created to identify factors predictive of failure of antithrombotic therapy. The authors generated Kaplan-Meier survival curves to determine the timing of recurrent TIA, stroke, or death after failure of antithrombotic therapy. RESULTS: Fifty-two patients had symptomatic intracranial atherosclerosis and fulfilled entry criteria. Twenty-nine of the 52 patients (55.8%) had cerebral ischemic events while receiving an antithrombotic agent (antiplatelet agents [55%], warfarin [31%], or heparin [14%]). In a Cox regression model, older age was an independent predictor of failure of antithrombotic therapy, and warfarin use was associated with a decrease in risk. Recurrent TIA (n = 7), nonfatal/fatal stroke (n = 6/1), or death (n = 1) occurred in 15 of 29 (51.7%) of the patients who failed antithrombotic therapy. The median time to recurrent TIA, stroke, or death was 36 days (95% CI 13 to 59). CONCLUSIONS: Patients with symptomatic intracranial atherosclerosis who fail antithrombotic therapy have extremely high rates of recurrent TIA/stroke or death. Recurrent ischemic events typically occur within a few months after failure of standard medical therapy. The high recurrence risk observed warrants testing of alternative treatment strategies such as intracranial angioplasty.     

FLAIR Vascular Hyperintensities in Acute ICA and MCA Infarction: A Marker for Mismatch and Stroke Severity?

Background: Vascular hyperintensities of brain-supplying arteries on stroke FLAIR MRI are common and represent slow flow or stasis. FLAIR vascular hyperintensities (FVH) are discussed as an independent marker for cerebral hypoperfusion, but the impact on infarct size and clinical outcome in acute stroke patients is controversial. This study evaluates the association of FVH with infarct morphology, clinical stroke severity and infarct growth in patients with symptomatic internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion. Methods: MR images of 84 patients [median age 73 years (IQR 65-80), 56.0% male, median NIHSS 7 (IQR 3-13)] with acute stroke due to symptomatic ICA or MCA occlusion or stenosis were reviewed. Vessel occlusions were identified by MRA time of flight and graded with the TIMI score. Diffusion and perfusion deficit volumes on admission and FLAIR lesion volumes on discharge were assessed. The presence and number of FVH were evaluated according to MCA-ASPECT areas, and associations with MR volumes, morphology of infarction, recanalization status, presence of white matter disease and hemorrhagical transformation as well as with stroke severity (NIHSS), stroke etiology and thrombolysis rate were analyzed. Results: FVH were detectable in 75 (89.3%) patients. The median number of FVH was 4 (IQR 2-7). Patients with FVH >4 presented with more severe strokes due to NIHSS (p = 0.021), had larger initial DWI lesions (p = 0.008), perfusion deficits (p = 0.001) and mismatch volumes/ratios (p = 0.005). The final infarct volume was larger (p = 0.005), and hemorrhagic transformation was more frequent (p = 0.029) in these patients. Conclusions: The presence of FVH indicates larger ischemic areas in brain parenchyma predominantly caused by proximal anterior circulation vessel occlusion. A high count of FVH might be a further surrogate marker for initial ischemic mismatch and stroke severity.     

影响急性脑梗死出血性转化的危险因素

目的 探讨急性脑梗死的出血性转化的危险因素。方法 收集2012年1月～2015年1月在湖北省恩施州利川市人民医院神经内科住院的急性脑梗死患者的临床及实验室检查资料,并在入院后10 d内行头颅CT复查,采用多变量logistic回归分析确定出血性转化的独立危险因素。结果 共纳入345例急性脑梗死患者,其中男205例,女140例,101例发生出血性转化。出血性转化组的年龄、脑梗死体积、脑卒中史或TIA史、高血压病、糖尿病、抗凝药和房颤的比例均显著高于非出血性转化组(P<0.05),而2组抗血小板聚集药、他汀类、高脂血症史、吸烟或饮酒史无明显差异(P>0.05)。多变量logistic回归分析显示年龄(OR=1.168,95%,CI=1.059～3.412; P=0.021)、梗死体积(OR=3.461,95%C1=1.317～6.270; P=0.044)和房颤(OR=1.284,95%C1= 1.117～2.903; P=0.015)为出血性转化的独立危险因素。结论 急性脑梗死患者出血性转化的发生率为29.3%,年龄、脑梗死体积和房颤为出血性转化的独立危险因素,绝大多数出血性转化不会加重临床症状,临床症状加重的患者主要是脑实质血肿型。     

磁共振多层并采扩散峰度成像与传统扩散加权成像识别急性缺血性卒中梗死核心的研究

目的与磁共振成像(magnetic resonance imaging,MRI)传统扩散加权成像(diffusion weighted imaging,DWI)对比,探讨MRI多层并采扩散峰度成像(multi-band EPI diffusion kurtosis imaging,m-DKI)界定急性缺血性卒中梗死核心的准确性。方法选择在发病3~8 h进行MRI检查的急性缺血性卒中患者,所有患者经灌注加权成像(perfusion weighted imaging,PWI)判定不存在缺血半暗带,没有接受静脉溶栓/动脉取栓治疗。基线扫描时加入传统DWI以及m-DKI序列,并在患者发病亚急性期([7±1)d]复查MRI扫描,利用Mricron软件分别对基线MRI检查表观扩散系数(apparent diffusion coefficient,ADC)图,平均扩散峰度(mean kurtosis,MK)图以及复查MRI T_1加权成像(T_1 weighted imaging,T_1WI)责任病灶体积进行测量,分别计算ADC图、MK图与T_1WI责任病灶体积的差值,并进行比较。结果入组的19例患者,1例患者DWI显示缺血病灶,但MK图及复查MRI均未见责任病灶;1例患者病灶位于基底节区附近,影响MK图责任病灶观察及测量。余17例患者MK图显示责任病灶的体积与亚急性期T_1WI责任病灶体积的差值为(0.25±0.37),而ADC图显示责任病灶的体积与亚急性期T_1WI体积的差值为(0.73±0.72)(t=3.968,P=0.001)。MK图责任病灶的体积更接近T_1WI的体积。结论与传统DWI相比,基线m-DKI显示责任病灶的体积更接近复查T_1WI的体积,对最终梗死核心的界定更为准确。     

Relevance of transient ischemic attack to early neurological recovery after nonlacunar ischemic stroke

BACKGROUND: We hypothesized that previous transient ischemic attack (TIA) had a favorable effect on early outcome after acute nonlacunar ischemic stroke. METHODS: Data of 1,753 consecutive patients with ischemic stroke collected from a prospective hospital-based stroke registry were studied. A comparison was made of the groups with and without previous TIA. Favorable outcome included spontaneous neurological recovery or grades 0-2 of the modified Rankin scale at hospital discharge. RESULTS: Previous TIA occurred in 55 (11.5%) of 484 patients with lacunar stroke and in 166 (13.1%) of 1,269 patients with nonlacunar stroke. The percentage of nonlacunar ischemic stroke patients with favorable outcome was 21.7% in those with a history of TIA compared to 15% without TIA (p < 0.03). In the lacunar stroke group, differences were not significant. In the multivariate analysis, TIA was an independent predictor of spontaneous in-hospital recovery. CONCLUSIONS: Prior TIA was associated with a favorable outcome in nonlacunar ischemic stroke, suggesting a neuroprotective effect of TIA possibly by inducing a phenomenon of ischemic tolerance allowing better recovery from a subsequent ischemic stroke.     

Impact of abnormal diffusion-weighted imaging results on short-term outcome following transient ischemic attack

OBJECTIVE: To characterize short-term prognoses among patients with transient ischemic attack (TIA) and normal diffusion-weighted imaging (DWI) results, TIA patients with abnormal DWI results (transient symptoms associated with infarction [TSI]), and patients with completed ischemic stroke (IS). DESIGN: Retrospective study. SETTING: University hospital. PATIENTS: We reviewed patient medical records between January 2003 and December 2004 with International Classification of Diseases, Ninth Revision codes for TIA at admission, resolution of neurological symptoms within 24 hours, magnetic resonance imaging within 48 hours, and a discharge diagnosis of TIA or IS. A random sample of 50 IS patients was selected from all IS admissions and discharges by International Classification of Diseases, Ninth Revision codes. Demographic, clinical, radiographic, and in-hospital outcome data were recorded. Three diagnostic categories were created: TIA with normal DWI results, TSI, and IS. Multivariate logistic regression was used to estimate the association between diagnostic category and rate of in-hospital stroke or recurrent TIA among the 3 groups. RESULTS: We identified 146 classic TIA (25% with TSI) and 50 IS cases. There were 4 recurrent TIAs and 6 strokes among patients with TSI (27.0%); 3 recurrent TIAs and no strokes among patients with normal DWI results (2.8%); and 1 recurrent stroke and no TIAs among IS patients (2.0%). Transient symptoms associated with infarction was independently associated with in-hospital recurrent TIA or stroke (adjusted odds ratio, 11.2; P < .01). CONCLUSIONS: Transient symptoms associated with infarction is associated with a greater rate of early recurrent TIA and stroke than both IS and TIA with normal DWI results. These data suggest that TSI may be a separate clinical entity with unique prognostic implications.     

MRI三维动脉自旋标记法对TIA的诊断价值

目的本研究拟运用MRI三维动脉自选标记法(3D-ASL),结合DWI及时间飞跃法MRA(3DTOF-MRA),探讨3D-ASL在TIA的诊断、血流灌注评估等方面的应用价值,为临床超早期诊断、治疗提供更多的理论依据。方法发病24 h内的TIA患者13例,入院时进行常规MRI、DWI、3D-TOF-MRA及3D-ASL扫描。观察所有患者MRA图,分析颅内血管及颈内动脉有无狭窄及异常,比较DWI所示梗死面积(SDWI)和全脑血流量(CBF)图上灌注异常面积(SASL)的差异,分别计算DWI和3D-ASL对TIA患者的检出率,并结合MRA分析造成脑组织血流灌注异常的原因。对于DWI阴性但ASL灌注异常,且MRA(或CTA)显示血管狭窄的患者,计算病灶侧和对侧相应区域的CBF值的比值(rCBF),比较rCBF与入院时(发病24 h内)的NIHSS、Glasgow昏迷评分量表(GCS)、mRS及神经内科临床评分量表(ABCD2)评分、患者发病时间以及一过性脑缺血症状发作持续时间有无相关性,并且比较分析rCBF值与MRA(或CTA)所示血管直径狭窄程度的相关性。结果(1)SASL>SDWI:13例TIA患者中,11例DWI未发现病灶,即SDWI=0,而SASL>0,且显示灌注减低;2例DWI阳性,但病灶面积仍SASL>SDWI。(2)3D-ASL对TIA的检出率明显高于DWI:DWI对TIA患者病灶的检出率为15%;3D-ASL对TIA患者病灶的检出率为69%。(3)rCBF与入院时(发病24 h内)的NIHSS、GCS、mRS及ABCD2评分的分值均无相关性;rCBF与患者发病时间及一过性脑缺血症状发作持续时间无相关性;rCBF值与MRA(或CTA)所示血管直径狭窄程度呈负相关关系(rs=-0.697,P=0.011)。结论3DASL与DWI相比,对TIA的诊断敏感性较高。及早行3D-ASL检查,并与DWI、MRA等序列联合应用,能更早发现灌注异常,并初步提示责任血管狭窄程度,为临床治疗提供科学依据。     

缺血性卒中/TIA患者抗栓药物的使用及影响因素分析：中国七城市门诊连续病例的横断面调查

目的 评估中国缺血性卒中(IS)或短暂性脑缺血发作（TIA）患者应用抗血栓药物（包括抗血小板药物和抗凝药物）的现况，并分析其影响因素。方法 采用横断面研究方法，调查2006年7月1日至8月15日期间，中国主要城市二、三级医院神经内科门诊连续IS或TIA患者近期的抗血栓药物使用情况。22家医院参加调查，总计2384例卒中患者连续入选；有3家不符合中心入选标准被除外，最后19家医院的资料被采用，总计有2283例卒中患者的数据纳入分析中。结果 2283例卒中患者中，使用阿司匹林者占71.9％，使用阿司匹林+氯吡格雷占4.2％，使用氯吡格雷者占7.3％，各种抗血小板药物合计例数占75.6％。伴心房颤动的81例卒中患者中，使用华发林者占17.3％。医疗保险[比值比（OR）1.473，95%可信区间（CI）1.088～1.994]、公费医疗（OR 1.632，95%CI 1.029～2.589）、月均收入≥500元以上（OR 2.136，95%CI 1.508～3.026）、高血压（OR 1.463，95%CI 1.159～1.847）和脂代谢紊乱（OR 1.499，95%CI 1.187～1.893）是卒中患者接受抗血小板药物的促进因素。患者年龄≥75岁（OR 0.701，95%CI 0.498～0.988）及改良的Rankin评分4～5分（OR 0.684，95%CI 0.486～0.965）是用药的阻碍因素。结论 中国大城市二、三级医院IS和TIA患者的抗血栓治疗现状不容乐观，各类抗血栓药物应用的比例较低，为改善以上状况，亟待探索有效的改进模式，缩短临床实践与指南间的差距。     

短暂性脑缺血发作的DWI表现和临床因素的关系

目的:评价磁共振弥散加权成像(diffusion-weighted MRI,DWI)对短暂性脑缺血发作(transient ischemic attack,TIA)患者的应用价值,以及DWI异常与临床因素的关系。方法:研究2006年3～9月间在发病后7天内进行常规MRI和DWI检查的81例TIA患者。对TIA患者DWI表现和临床因素的关系进行分析。结果:32例TIA患者有DWI异常(32／81,39％),49例无DWI异常(49／81,61％)。DWI异常者更多见于TIA持续时间较长(≥30分钟),发作频繁,有运动障碍,失语,脑卒中或TIA史,糖尿病和房颤者。32例有DWI异常者中13例在常规MRI上未显示病灶, 19例在常规MRI(T2和FLAIR)上也显示异常。结论:在临床诊断的TIA患者中,症状持续时间较长,发作频繁,运动障碍,失语,脑卒中或TIA史,糖尿病和房颤者是与DWI异常显著相关的因素。     

Early magnetic resonance imaging prediction of arterial recanalization and late infarct volume in acute carotid artery stroke.

In patients with acute ischemic stroke, early recanalization may save tissue at risk for ischemic infarction, thus resulting in smaller infarcts and better clinical outcome. The hypothesis that clinical and diffusion- and perfusion-weighted imaging (DWI, PWI) parameters may have a predictive value for early recanalization and final infarct size was assessed. Twenty-nine patients were prospectively enrolled and underwent sequential magnetic resonance imaging (1) within 6 hours from hemispheric stroke onset, before thrombolytic therapy; (2) at day 1; and (3) at day 60. Late infarct volume was assessed by T2 -weighted imaging. At each time, clinical status was assessed by the National Institutes of Health Stroke Scale (NIHSS). Twenty-eight patients had arterial occlusion at day 0 magnetic resonance angiography (MRA). They were classified into two groups according to day 1 MRA: recanalization (n = 18) versus persistent occlusion (n = 10). Any significant differences between these groups were assessed regarding (1) PWI and DWI abnormality volumes, (2) relative and absolute time-to-peak (TTP) and apparent diffusion coefficient within the lesion on DWI; and (3) day 60 lesion volume on T2 -weighted imaging. Univariate and multivariate logistic regression analysis showed that the most powerful predictive factors for recanalization were lower baseline NIHSS score and lower baseline absolute TTP within the lesion on DWI. The best predictors of late infarct size were day 0 lesion volume on DWI and day 1 recanalization. Early PWI and DWI studies and day 1 MRA provide relevant predictive information on stroke outcome.