TIA, RIND, minor stroke: a continuum, or different subgroups? Dutch TIA Study Group

Long-Term Incidence of Ischemic Stroke After Transient Ischemic Attack: A Nationwide Study From 2014 to 2020

BACKGROUND

The short-term incidence of ischemic stroke after a transient ischemic attack (TIA) is high. However, data on the long-term incidence are not well known but are needed to guide preventive strategies.

METHODS

Patients with first-time TIA (index date) in the Danish Stroke Registry (January 2014-December 2020) were included and matched 1:4 with individuals from the background population and 1:1 with patients with a first-time ischemic stroke on the basis of age, sex, and calendar year. The incidences of ischemic stroke and mortality from index date were estimated by Aalen-Johansen and Kaplan-Meier estimators, respectively, and compared between groups using multivariable Cox regression.

RESULTS

We included 21 500 patients with TIA, 86 000 patients from the background population, and 21 500 patients with ischemic stroke (median age, 70.8 years [25th-75th percentile, 60.8-78.7]; 53.1% males). Patients with TIA had more comorbidities than the background population, yet less than the control stroke population. The 5-year incidence of ischemic stroke after TIA (6.1% [95% CI, 5.7-6.5]) was higher than the background population (1.5% [95% CI, 1.4-1.6], P<0.01; hazard ratio, 5.14 [95% CI, 4.65-5.69]) but lower than the control stroke population (8.9% [95% CI, 8.4-9.4], P<0.01; hazard ratio, 0.58 [95% CI, 0.53-0.64]). The 5-year mortality for patients with TIA (18.6% [95% CI, 17.9-19.3]) was higher than the background population (14.8% [95% CI, 14.5-15.1], P<0.01; hazard ratio, 1.26 [95% CI, 1.20-1.32]) but lower than the control stroke population (30.1% [95% CI, 29.3-30.9], P<0.01; hazard ratio, 0.41 [95% CI, 0.39-0.44]).

CONCLUSIONS

Patients with first-time TIA had an ischemic stroke incidence of 6.1% during the 5-year follow-up period. After adjustment for relevant comorbidities, this incidence was approximately 5-fold higher than what was found for controls in the background population and 40% lower than for patients with recurrent ischemic stroke.

Cost-Minimization Analysis of Computed Tomography versus Magnetic Resonance Imaging in the Evaluation of Patients with Transient Ischemic Attacks at a Large Academic Center

Background

The type of neuroimaging for the evaluation of transient ischemic attack (TIA) is debatable. Many patients undergo head computed tomography (CT) with or without CT angiogram (CTA) while being at the emergency department (ED) and later magnetic resonance imaging (MRI) with MR angiogram (MRA) during admission. We hypothesized that evaluation with only one imaging modality (CT/CTA or MRI/MRA) is sufficient to formulate a treatment plan. We looked for the most cost-effective way to evaluate TIA patients.

Methods

We performed a retrospective chart review of 82 patients with TIA. All patients had completely resolved neurological deficit at the time of their evaluation in the ED. We divided the patients into two groups. In group 1, the evaluation included CT with CTA of the head and neck. In group 2, the evaluation included brain MRI with MRA or CTA of the head and neck. We compared these two groups for clinical characteristics and etiological evaluations of stroke/TIA. The outcomes were measured by the number of therapeutic adjustments for the prevention of another ischemic stroke/TIA at the time of discharge from the hospital and revascularization procedures. We counted the following as therapeutic adjustment: (1) antiplatelet therapy was started de novo; (2) anticoagulation was started; (3) arterial revascularization procedure was performed, and (4) one antiplatelet agent was substituted for another. We performed a cost-effectiveness analysis if the outcomes of the two groups were different and a cost-minimization analysis if there was no difference in the outcomes. All cost calculations were made based on Medicare CPT codes.

Results

Group 1 included 23 patients and group 2 59 patients. The patients in both groups had similar demographic and clinical characteristics. There was no difference in other etiological evaluations in groups 1 and 2. All patients underwent head CT as the first tool of evaluation whether MRI was done later or not. Therapeutic adjustments and revascularization procedures did not differ between the two groups. All head CTs showed no acute changes. MRI showed small ischemic infarcts in 44% of the patients in group 2. The average per-patient cost of neuroimaging with CT/CTA was USD 1,460.00, with CT and MRI/MRA USD 1,569 and with CT/CTA and brain MRI USD 2,090.00 (p < 0.01).

Conclusion

Either MRI/MRA or CT/CTA might be sufficient for the evaluation of patients with TIA or small asymptomatic strokes. If head CT at the ED is bypassed, a brain MRI with MRA of the head and neck would be the most informative tool at the lowest cost. Prospective studies with larger numbers of patients are needed for a better understanding of the safety and cost of imaging tools used for patients with TIA.

Acute brain infarction detected by CCT and stroke risk in patients with transient ischemic attack lasting <1 hour

BACKGROUND AND PURPOSE

This study aimed to determine the frequency and associated factors of acute brain infarction (ABI) detected by noncontrast cranial computed tomography (CCT) in patients with transient ischemic attack (TIA) of symptom duration <1 h and to investigate the association between evidence of ABI and short-term risk of stroke.

METHODS

During a 54-month period (starting November 2007), consecutive patients with TIA (symptom duration <1 h) admitted and imaged with CCT were prospectively evaluated. Adjusted logistic regression was used to estimate odds ratios (ORs).

RESULTS

Of 1021 patients (mean age, 74.5 ± 11 years; 52% female) with TIA (symptom duration <1 h) imaged with CCT at admission, 68 patients (6.7%; 95% CI, 5.3-8.3%) exhibited TIA-related ABI. Adjusted logistic regression showed that ABI was independently correlated with atrial fibrillation (AF) (OR, 3.3; 95% CI, 1.4-7.9; p = 0.006) and time between onset and CT assessment >6 h (OR, 2.5; 95% CI, 1.1-6.1; p = 0.034). During hospitalization (5 ± 3 d), 22 patients (2.2%; 95% CI, 1.4-3.1%) developed a stroke. Patients with ABI had higher stroke rates than those without (10.3% and 1.6%, respectively; p < 0.001). Adjusted logistic regression revealed that stroke risk was independently correlated with ABI (OR, 5.3; 95% CI, 1.8-15.0; p = 0.002) and AF (OR, 2.6; 95% CI, 1.1-6.4; p = 0.026).

CONCLUSIONS

Detection of ABI by CCT in TIA patients with symptom duration <1 h may depend on timing of CCT assessment and presence of AF. Evidence of ABI indicates an elevated stroke risk during hospitalization.

Use of cranial CT to identify a new infarct in patients with a transient ischemic attack

Research on infarct detection by noncontrast cranial computed tomography (CCT) in patients with transient ischemic attack (TIA) is sparse. However, the aims of this study are to determine the frequency of new infarcts in patients with TIA, to evaluate the independent predictors of infarct detection, and to investigate the association between a new infarct and early short-term risk of stroke during hospitalization. We prospectively evaluated 1533 consecutive patients (mean age, 75.3 ± 11 years; 54% female; mean National Institutes of Health Stroke Scale [NIHSS] score, 1.7 ± 2.9) with TIA who were admitted to hospital within 48 h of symptom onset. A new infarct was detected by CCT in 47 (3.1%) of the 1533 patients. During hospitalization, 17 patients suffered a stroke. Multivariate logistic regression analysis revealed the following independent predictors for infarct detection: NIHSS score ≥10 (odds ratio [OR], 4.8), time to CCT assessment >6 h (OR 2.2), and diabetes (OR 2.3). The evidence of a new infarct was not associated with the risk of stroke after TIA. The frequency of a new infarct in patients with TIA using CCT is low. The use of the CCT tool to predict the stroke risk during hospitalization in patients with TIA is found to be inappropriate. The estimated clinical predictors are easy to use and may help clinicians in the TIA work up.

A severe neurological event during a local anaesthesia phlebectomy

A 58 year old female patient underwent an intervention of phlebectomy below the knee. The patient gradually developed a severe neurological event and the Glasgow Coma Score decreased dramatically. After two and a half hours from onset, general conditions gradually improved and recovered completely. Lidocaine neurotoxicity was excluded. A right side motor deficit strongly suggests a transient ischaemic attack. As to invasivity, phlebectomy can be compared with liquid and foam sclerotherapy so that the simple question arises of also comparing their adverse effects. We have the strong conviction that this case may only be a co-incidental association.

Predictors of outcome in acute ischemic cerebrovascular syndromes: The GIFA study

BACKGROUND

Today it may be more useful to use the term acute ischemic cerebrovascular syndrome (AICS) to define a spectrum of disease ranging from TIA to stroke and that share a similar underlying pathophysiology: cerebral ischemia. The aim of this study is to evaluate the prognostic importance of some demographic, laboratory and clinical variables on the outcome in hospitalized patients with a discharge diagnosis suggestive of acute ischemic cerebral syndrome (AICS).

METHODS

17,377 Subjects were enrolled in the GIFA study, a multicenter survey of hospitalized older patients. 1878 Subjects with a main discharge diagnosis suggestive of acute ischemic cerebrovascular syndrome (AICS) represent the final sample. The primary outcomes of this study were: (1) in-hospital mortality; (2) cognitive impairment at discharge; (3) functional status at discharge.

RESULTS

Age, WBC count, glucose blood level at admission and Charlson index score were directly associated with in-hospital mortality. Age, WBC count, Charlson index score and disability at admission are directly associated with cognitive impairment at discharge. Finally, age, Charlson index score and disability at admission are directly associated with disability at discharge.

CONCLUSIONS

Our study evaluated prognosis in the light of the three main aspects of mortality, disability and cognitive impairment that showed substantial sharing for most of the prognostic factors, probably owing to the possible strict association of these outcome indicators with markers of ischemic brain damage extent (WBC) and/or individual response to an ischemic event by neuroplasticity (age, comorbidity) in subjects with AICS.

Diffusion-weighted MR imaging in transient ischaemic attacks

The purpose of this study was to determine frequency and the characteristics of diffusion-weighted imaging (DWI) abnormalities in patients with transient ischaemic attack (TIA). We analysed data of 98 consecutive patients (mean age: 60.6+/-15.4 years, 56 men) admitted between January 2003 and April 2004 for TIA. Age, gender, symptom type and duration, delay from onset to magnetic resonance imaging (MRI), probable or possible TIA and cause of TIA were compared in patients with (DWI+) and without (DWI-) lesions on DWI. Volume and apparent diffusion coefficient (ADC) values of DWI lesions were computed. DWI revealed ischaemic lesions in 34 patients (34.7%). Lesions were small (mean volume: 1.9 cm(3)+/-3.3), and ADC was moderately decreased (mean ADC ratio: 79.5%). The diagnosis of TIA was considered as probable in all DWI+ patients. A multiple logistic regression model demonstrated that TIA duration greater than or equal to 60 min (OR, 7.6; 95% CI, 2.3-25.7), aphasia (OR, 9.2; 95% CI, 2.7-31.4) and motor deficit (OR, 5.1; 95% CI, 1.5-17.8) were independent predictors of DWI lesions. Prolonged TIA duration, aphasia and motor deficits are associated with DWI lesions. More than half of TIA patients with symptoms lasting more than 60 min have DWI lesions.

Antiplatelet Drugs In the Secondary Prevention After Stroke

Background and Purpose— Arterial disease resulting in cerebral ischemia can be classified into large vessel disease (LVD) and small vessel disease (SVD). We assessed whether antiplatelet drugs were more efficacious in large than in small vessel cerebrovascular disease.

Methods— Individual patient data of the second European Stroke Prevention Study (n=6602), in which patients with a previous transient ischemic attack or ischemic stroke were randomized to aspirin, dipyridamole, their combination, or placebo, were reanalyzed. Type of vessel disease was classified according to clinical symptoms or physical examination. Presence of a lacunar syndrome was considered typical for SVD and evidence of cortical dysfunction for LVD. Vascular events (nonfatal stroke, nonfatal myocardial infarction, nonfatal other vascular event, or vascular death) were taken as outcome. Cox regression analyses were performed.

Results— A total of 419 first vascular events occurred in 2600 patients with SVD and 367 in 1816 patients with LVD (mean follow-up 1.7 years). For aspirin versus placebo, the hazard ratio (HR) was 0.86 (95% CI, 0.66 to 1.11) in patients with SVD and 0.80 (95% CI, 0.61 to 1.06) in those with LVD ( P interaction =0.74). For dipyridamole versus placebo, the HR was 0.86 (95% CI, 0.67 to 1.12) in patients with SVD and 0.90 (95% CI, 0.68 to 1.19) in patients with LVD ( P interaction =0.84). Similar observations were made for the outcome stroke only.

Conclusions— Our findings do not concur with the hypothesis that aspirin, dipyridamole, or the combination may be especially effective in preventing vascular events in patients with previous cerebral ischemia that was caused by LVD compared with SVD.

Acute Ischemic Cerebrovascular Syndrome

Background— Existing diagnostic classification systems for cerebrovascular disease are based primarily on clinical impression of temporal features, clinical syndrome, inferred localization, or ischemic mechanism. Diagnostic certainty of the ischemic pathology based on supportive or refuting laboratory or radiological evidence has been of secondary importance.

Summary of Comment— Acute ischemic cerebrovascular syndrome (AICS) describes a spectrum of clinical presentations that share a similar underlying pathophysiology: cerebral ischemia. Diagnostic criteria for AICS incorporate prior classification systems and currently available information provided by neuroimaging and laboratory data to define 4 categories ranging from “definite AICS” to “not AICS,” which define the degree of diagnostic certainty.

Conclusions— Clinical trials testing new treatments for acute ischemic stroke or secondary stroke prevention should limit enrollment to patients with “definite” AICS whenever feasible.

Diffusion-weighted MRI in evaluation of transient ischemic attack

Diffusion-weighted magnetic resonance imaging (DWI) is a sensitive diagnostic tool for detecting recent ischemic lesions in patients with transient ischemic attacks (TIAs), but the interpretation of the presence or absence of DWI abnormalities in TIA patients still remains controversial. To elucidate the pathophysiology underlying those lesions, we analyzed DWI abnormalities in patients with recent TIAs. Based on 45 consecutive patients with TIAs who underwent DWI within 10 days of onset, demographic data and clinical manifestations were analyzed in relation to the DWI abnormalities. According to the method utilized in the Oxfordshire Community Stroke Study, clinical manifestations were classified into classical lacunar syndrome and non-lacunar symptoms. Based on the vascular distributions of ischemic lesions, the DWI abnormalities were classified into small-vessel and large-vessel lesions. DWI abnormalities were detected in 14 (31%) of 45 TIA patients. Seven (50%) of 14 DWI-positive patients had occlusive vascular lesions on intracranial magnetic resonance angiography, while only 5 (16%) of 31 DWI-negative patients had occlusive lesions (P < .05). No other demographic or clinical features, including risk factor and presence of cardiac disease, differed significantly between the DWI-positive and DWI-negative patient groups. Four (46%) of 9 DWI-positive patients who had a classical lacunar syndrome also showed small-vessel lesions on DWI, whereas all 5 patients who had non-lacunar symptoms showed large-vessel lesions. We concluded that although DWI abnormalities were detected in only one third of our TIA patients, DWI abnormalities were closely related to intracranial vascular occlusive lesions. The combination of DWI and MRA was useful for detecting large-artery lesions in patients displaying a classical lacunar syndrome.

Detection of diffusion-weighted MRI abnormalities in patients with transient ischemic attack: correlation with clinical characteristics

BACKGROUND AND PURPOSE

Although diffusion-weighted MRI (DWI) has demonstrated clear superiority over other conventional imaging modalities in the detection of hyperacute cerebral ischemia, its value in the evaluation of patients with transient symptoms has received only limited attention. We assessed the utility of DWI in patients with transient ischemic attack (TIA) to further evaluate the usefulness of this technique in these individuals.

METHODS

A retrospective analysis was performed on all patients entered in the Stanford Stroke Center database during 1997-2001 who were clinically diagnosed with a TIA and who had also undergone a DWI scan <or=3 days after symptom onset. The relationship between DWI-detected findings and patients' clinical presentation was then analyzed.

RESULTS

Seventy-five patients experiencing 78 TIAs who also underwent DWI within 3 days of symptom onset were identified. DWI-detected abnormalities were present in 16 of 78 cases (21%). Patients with positive DWI scans were 9.6 times more likely to have had symptom duration >or=1 hour, 16 times more likely to have had motor deficits, and 25 times more likely to have had aphasia than patients with negative DWI scans. The combination of all 3 symptoms was 100% specific for an abnormality on DWI. In 7 of 16 cases (44%), a DWI abnormality was present on both DWI and conventional imaging (T2-weighted imaging or fluid-attenuated inversion recovery [FLAIR]). In all of these cases the DWI clarified the extent or acuity of the lesion (n=7) or identified additional lesions not detected by conventional imaging (n=9).

CONCLUSIONS

In TIA patients, symptom duration >or=1 hour, motor deficits, and aphasia were each independently correlated with detecting an abnormality with DWI. DWI was also helpful in differentiating between chronic versus acute lesions. These data may be of value in identifying those TIA patients for whom MRI evaluation with DWI is of greatest clinical utility.

Epidemiological impact in the United States of a tissue-based definition of transient ischemic attack

BACKGROUND AND PURPOSE

The traditional definition of transient ischemic attack (TIA), based on an arbitrary time criterion of symptom resolution within 24 hours, is problematic because a large number of patients with traditionally defined TIAs have a relevant cerebral infarction on brain imaging. The objective of this study was to characterize the epidemiological impact of adopting a tissue-based definition of TIA.

METHODS

Estimates of the annual US incidence of traditionally defined transient ischemic attacks were abstracted from the literature. Models were then constructed for determining the frequency of brain injury in traditionally defined TIAs, derived from recent human studies of MR diffusion-weighted imaging (DWI) in transient cerebral ischemia.

RESULTS

Traditionally defined US TIA annual incidence rates ranged from 37 to 107 per 100,000 per year. Across 5 series, the raw frequency of DWI positivity in traditionally defined TIAs was 44%. Adjusting for an overrepresentation of longer-duration TIAs in MR series yielded an expected frequency of diffusion MRI positivity of 33% in unselected, traditionally defined TIAs. Applying this model to the US population in the year 2000 showed that adopting a tissue-based definition of TIA would decrease the annual number of events classified as TIAs from 179,840 to 120,493 and increase events classified as strokes from 821,181 to 880,520.

CONCLUSIONS

Adopting a tissue-based definition of transient ischemic attack would reduce estimates of the annual incidence of TIA by 33% (sensitivity analysis range, 19% to 44%) and increase estimates of the annual incidence of stroke in the United States by 7% (range, 4% to 10%).

Diffusion weighted magnetic resonance imaging in the diagnosis of reversible ischaemic deficits of the brainstem

OBJECTIVES

To evaluate the sensitivity of diffusion weighted magnetic resonance imaging (MRI) for the diagnosis of clinically suspected reversible ischaemic deficits of the brainstem.

METHODS

A total of 158 consecutive patients presenting with acute signs of brainstem dysfunction were investigated using EPI diffusion weighted MRI within 24 hours of the onset of symptoms. High resolution T1 and T2 weighted imaging was performed as a follow up after a median of six days.

RESULTS

Fourteen of the 158 patients had a complete clinical recovery within 24 hours (transitory ischaemic attack (TIA)), and 19 patients recovered in less than one week (prolonged reversible neurological deficit (RIND)). Diffusion weighted MRI showed acute ischaemic deficits in 39% of patients with transient neurological deficits. The detection rate seemed to be higher in patients with longer lasting symptoms, but the difference between patients with TIA (29%) and RIND (47%) was not significant.

CONCLUSIONS

Diffusion weighted MRI is a sensitive indicator of acute ischaemic brainstem deficits even in patients with reversible neurological deficit. Early identification of patients with TIA and increased risk of stroke may influence acute management and improve patient outcome.

Diffusion-weighted MR imaging in the acute phase of transient ischemic attacks

BACKGROUND AND PURPOSE

Radiologic assessment of acute transient ischemic attacks (TIAs) has been handicapped by the low sensitivity of CT and conventional MR imaging for acute small-vessel infarction and the difficulty in differentiating between acute and chronic lesions by use of these methods. Our purpose was to evaluate the incidence of TIA-related infarction by using diffusion-weighted MR imaging to determine whether the presence of a diffusion imaging abnormality correlates with the duration of symptoms or cause of TIA.

METHODS

We prospectively studied 58 consecutive patients with acute TIA by use of diffusion-weighted imaging. All MR imaging was performed with a 1.5-T whole-body system with 24-mT/m gradient strength and an echo-planar-capable receiver. All patients were imaged within 10 days of stroke onset.

RESULTS

Thirty-nine patients (67%) manifested a diffusion imaging abnormality consistent with acute ischemia. Cortical lesions were identified in 54% of these patients; most of them associated with other acute ischemic lesions. Subcortical lesions were identified in 46%; most of them were isolated from other lesions. The mean duration of symptoms in patients with no TIA-related diffusion imaging abnormalities was 0.96 hours (median, 0.33 hours) compared with a mean of 6.85 hours (median, 1.53 hours) in patients with diffusion imaging abnormalities (P =.025, Mann-Whitney U test). This significant correlation between the duration of TIA symptoms and the presence of TIA-related abnormalities was lost when we excluded from the analysis patients whose symptoms lasted longer than 6 hours (P =.513, Mann-Whitney U test). No significant correlation was observed between the size of TIA-related lesions and the duration of symptoms or cause of TIA.

CONCLUSION

Two thirds of our TIA patients showed focal abnormalities indicative of acute ischemic lesions on diffusion-weighted images. This incidence is higher than that previously reported in the literature. The presence of such abnormalities increased with increasing total symptom duration, but this relation was not observed when only patients whose symptoms lasted less than 6 hours were considered. No significant correlation was observed between the cause and presence of TIA-related lesions on diffusion-weighted MR images. These TIA-related lesions are probably irreversible and may lead to subsequent infarct.

Management of the first-time transient ischaemic attack

The assessment and management of patients with a suspected transient ischaemic attack of the brain or eye is a daily task in busy emergency departments. They are common, affecting about 50 per 100,000 population each year. Conditions which mimic a transient ischaemic attack are even more common (e.g. migraine aura, partial seizures, benign paroxysmal positional vertigo, hysteria). This comprehensive review outlines an approach to the management of this complex and challenging problem.

Systematic review of diffusion and perfusion imaging in acute ischemic stroke

BACKGROUND AND PURPOSE

Recent advances in neuroimaging have raised hopes of early and accurate identification of ischemic brain and the discrimination of dead from salvageable tissue. We sought to determine whether the data published so far are enough to establish the roles of these techniques in everyday clinical practice.

METHODS

A systematic review of studies of MR diffusion-weighted imaging (DWI), perfusion imaging (PI), or a combination of the two, in human stroke, excluding abstracts and case reports. One reviewer extracted information on the size of each study, its main purpose, methodological details, and results.

RESULTS

We identified 47 studies of DWI, 18 studies of MR PI alone or in combination with another advanced imaging modality, and 19 studies of DWI and PI together. Although high proportions of the studies were prospective and gave good details of the imaging sequences used, the majority gave very limited details on patient selection and clinical characteristics or blinded imaging assessment. Pathophysiological changes were inferred from DWI/PI patterns that were not supported by other data.

CONCLUSIONS

Despite considerable enthusiasm for and promise of these techniques, there is not sufficient information available in these studies to enable us to draw firm conclusions about the sensitivity and specificity of these techniques for identification of either ischemic lesions not visible by other means or salvageable tissue. Future studies should include larger numbers of carefully described patients, assess the contribution of DWI over and above other imaging, obtain follow-up at an appropriate time interval to determine accurate clinical and neuroradiological outcomes, and assess DWI/PI abnormality with reperfusion in randomized treatment trials. Investigators should also be encouraged to combine their individual patient data in meta-analyses to obtain a more robust assessment of the value of DWI and PI from larger sample sizes.

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.

Influence of treated blood pressure on progression of silent cerebral infarction

PURPOSE AND METHODS

To examine whether treatment for hypertensive patients prevents the progression of cerebral infarction, we performed magnetic resonance imaging (MRI) repeatedly at mean intervals of 22 months on 117 Japanese subjects aged 65-89 (mean 74 years), including 84 hypertensive patients. The patients were given various anti-hypertensive agents, and the blood pressure of each patient was monitored periodically during the observation period. Depending on the average blood pressure at the end of the follow-up period, hypertensive patients were classified into three subgroups: normotension (N), borderline (B) and hypertension (H). None had a prior history of symptomatic cerebral infarction and neurological abnormalities. The number of infarcted lesions were determined on brain MRI by two independent observers.

RESULTS

Silent cerebral infarction (SCI) lesions were observed in 42 hypertensive subjects (50.0%) and in eight control subjects (24.2%) on enrollment. The numbers of SCI lesions increased in 33 hypertensive subjects (39.3%) and three control subjects (9.1%) during the observation period. In the hypertensive subjects, an increased number of infarcted lesions was found in six of 28 subjects in group N (21.4%), 17 of 44 in group B (38.6%), and 10 of 12 in group H (83.3%). Thus, blood pressure controlled to the normal level appears to result in a lower incidence of progression of infarcted areas in patients with hypertension (N versus H, P < 0.001).

CONCLUSION

Our data indicate that an appropriate anti-hypertensive treatment reduces the risk of a cerebrovascular accident in hypertensive patients.

Diagnosis of transient ischemic attack by the nonneurologist. A validation study

BACKGROUND AND PURPOSE

Interobserver reliability of the diagnosis of transient ischemic attack (TIA) is low, and diagnosis of TIA made by nonneurologists is often erroneous. We sought to validate the diagnosis of TIA made by general practitioners (GPs) and by hospital emergency service physicians (emergency MDs).

METHODS

A list of 20 neurological symptoms was distributed to 20 GPs and 22 neurologists who graded the compatibility of each symptom with the TIA diagnosis. At least two neurologists validated TIA diagnoses made by GPs for patients under their care or by emergency MDs.

RESULTS

Compared with neurologists, GPs considered "confusion" and "unexplained fall" more often compatible with TIA and "lower facial palsy" and "monocular blindness" less often compatible with TIA. Validation of diagnosis by GP was confirmed in 10 patients (19%); 26 patients had strokes, and 16 (31%) had a noncerebrovascular disorder. Validation of diagnosis by emergency MD was confirmed in 4 patients (13%); 10 patients had strokes, and 17 (55%) had noncerebrovascular disorders. The most frequent conditions misdiagnosed as TIAs were transient disturbances of consciousness, mental status, and balance.

CONCLUSIONS

The TIA concept is understood differently by neurologists and nonneurologists. GPs and emergency MDs often label minor strokes and several nonvascular transient neurological disturbances as TIAs. Until this misconception of TIA is changed, the term TIA should probably be avoided in the communication between referring physicians and neurologists. If not referred to a neurologist, one third to one half of patients labeled with a diagnosis of TIA will be inappropriately managed.

Persisting perfusion defect in transient ischemic attacks: a new clinically useful subgroup?

BACKGROUND AND PURPOSE

Cerebral infarction and prolonged regional hypoperfusion have been described in patients with transient ischemic attacks (TIAs). The aim of this study was to compare the sensitivity of single-photon emission CT (SPECT) with that of brain CT and to evaluate the clinical significance of differentiation of TIA patients with or without focal hypoperfusion.

METHODS

From a hospital-based population, we studied the SPECT and CT findings in 76 consecutive patients, without a stroke history, who presented with TIA in the carotid artery territory. The recorded variables were the time of SPECT, imaging (<36 or > or = 36 hours), clinical presentation, history of previous TIA(s), duration of the presenting attack (<2 or > or = 2 hours), vascular risk factors, and etiology. We used both visual and semiquantitative analyses for the SPECT evaluation. Acetazolamide challenge was not performed.

RESULTS

The overall SPECT sensitivity was 36% (27/76). When brain CT and SPECT were performed in the same patients, the SPECT sensitivity was significantly higher than that of CT (19/59 [32%] versus 8/59 [14%]; P=.007). The SPECT sensitivity was not dependent on the time of investigation, duration of attacks, history of TIA(s), or the clinical presentation. The vascular risk and etiologic factors were not significantly different between the patients with or without prolonged focal hypoperfusion. Logistic regression did not identify any variable to discriminate the two groups.

CONCLUSIONS

Despite its better sensitivity compared with CT, SPECT performed without the acetazolamide test provides no additional clinically useful information on the vascular risk factors and etiology in TIA patients.

Transient ischemic attacks

Preview All transient ischemic attacks are not created equal. However, they are a medical emergency, and all patients should be hospitalized for urgent evaluation of their risk for stroke or myocardial infarction. For optimal management, it must be determined whether an ischemic attack affects the anterior or posterior circulation. In this article, the authors review current medical options for stroke prevention and the indications for carotid endarterectomy.

Does cerebral infarction after a previous warning occur in the same vascular territory?

BACKGROUND AND PURPOSE

The aim of this study was to compare the territory of cerebral infarcts on follow-up with that of the preceding transient ischemic attack or nondisabling stroke.

METHODS

The Dutch TIA Trial was a randomized, double-blind, controlled trial, in which the secondary preventive effects of two doses of aspirin were compared in patients with a transient ischemic attack or nondisabling stroke. On the basis of clinical symptoms and computed tomography, qualifying events were classified as pertaining to the left carotid, right carotid, or vertebrobasilar circulation.

RESULTS

In 2,993 patients the territory of the qualifying event was that of the left carotid in 1,281 (43%), the right carotid in 1,090 (36%), and the vertebrobasilar in 444 (15%); the territory was uncertain in 178 (6%). On follow-up (mean, 2.6 years), 184 of the 2,371 patients with a baseline event in the carotid circulation suffered a recurrent ischemic stroke (7.8%), as did 28 of the 444 patients in the vertebrobasilar group (6.3%); 117 of these 212 infarcts (55%; 95% confidence interval, 49-62) occurred in the same territory (108 in the ipsilateral carotid and nine in the vertebrobasilar territory) as the event at baseline, compared with 39% to be expected by chance alone (95% confidence interval, 32-45). In the carotid groups patients were significantly more likely to have a subsequent ischemic event in the same territory as at entry than patients in the vertebrobasilar group (relative risk, 1.8; 95% confidence interval, 1.1-3.2). The average interval between the qualifying event and the subsequent stroke was significantly shorter (mean, 167 days; 95% confidence interval, 77-257) if the vascular territory was the same.

CONCLUSIONS

These results suggest that single artery disease accounts for at most one half of the strokes on follow-up, relatively more often in the carotid territory, and that recurrent strokes from the same arterial lesion occur sooner than strokes associated with other lesions.

Hypodensity of the cerebral white matter in patients with transient ischemic attack or minor stroke: influence on the rate of subsequent stroke. Dutch TIA Trial Study Group

In a prospective study of 3,017 patients with transient ischemic attack or minor ischemic stroke from the Dutch Transient Ischemic Attack Trial, the presence or absence of diffuse hypodensity of the white matter on a baseline computed tomography (CT) scan of the brain was related to the occurrence of subsequent stroke. On entry, 337 patients were judged to have diffuse hypodensity of the white matter on CT; they were older (71.4 +/- 7.4 years versus 64.4 +/- 9.9 years), more often had hypertension (50% versus 41%), and more often had lacunar infarcts on CT scan (40% versus 26%) than did patients with normal white matter. Strokes, fatal or nonfatal, occurred in 51 (15%) of the patients with diffuse hypodensity of the cerebral white matter, compared to 217 (8%) in the group with normal white matter (crude hazard ratio, 2.0; 95% confidence interval, 1.4-2.7). After adjustment for age and other relevant entry variables, the hazard ratio was 1.6 (95% confidence interval, 1.2-2.2). In patients younger than 70 years the crude hazard ratio was 2.7 (95% confidence interval, 1.7-4.2). The distribution between the main subtypes of stroke was similar for patients with and those without diffuse hypodensity of the cerebral white matter: Intracerebral hemorrhage occurred in 6 and 9%, cortical infarction in 47 and 45%, and lacunar infarction in 34 and 29%, respectively. We conclude that hypodensity of the cerebral white matter in patients with transient ischemic attack or minor stroke is associated with an extra risk of future stroke, from large as well as from small vessels, and particularly in patients under 70 years old; this increase of risk is independent of other risk factors for stroke.