Transient ischemic attacks with and without a relevant infarct on computed tomographic scans cannot be distinguished clinically. Dutch Transient Ischemic Attack Study Group

Comparison of the post-embolization effects of tissue-plasminogen activator and simvastatin on neurological outcome in a clinically relevant rat model of acute ischemic stroke

Data has emerged, largely from non-thromboembolic animal models of stroke, that suggests that statins, which have efficacy in preventing strokes when given pre-ischemically, may have a positive effect on stroke even when given post-ischemically, possibly through pleitropic cerebrovascular effects. The goal of this study was to characterize the effects of IV tPA in a clinically relevant model of stroke utilizing a vascular occlusion with a freshly formed clot, and evaluate the effects of post-ischemic administration of simvastatin on stroke outcome in this model. Neurological deficit, clot burden, and lesion volume were assessed after treatment with tPA in one experiment, and after treatment with simvastatin in another. In the tPA experiment, treatment with 10mg/kg of tPA IV (with 20% given as an initial bolus, and 80% given as an infusion over the remaining 30 min), starting within an hour after stroke, resulted in significant reductions, compared with control animals, in neurological deficit (mean+/-SD neuroscores of 21.5+/-21.1 and 30+/-29.3, respectively, p=0.005), clot burden (p=0.010) and lesion volume (p=0.049) at 24h. In the simvastatin experiment on the other hand, treatment with a 20mg/kg of simvastatin as a single intraperitoneal dose within an hour after stroke resulted in no salutary effects on neurological deficit, clot burden or lesion volume compared with controls at 24h. These results suggest that more research needs to be done to fully ascertain the therapeutic potential and optimal dosing paradigm of a post-ischemic treatment with a statin.

Multidetector row CT of the brain and carotid artery: a correlative analysis

AIM

To evaluate the association between types of carotid plaque, the presence of prior ischaemic events detectable with CT, and patient's symptoms.

MATERIALS AND METHODS

Between January 2004 and May 2006, 112 patients were evaluated using multidetector row computed tomography angiography (MDCTA) of the carotid arteries and computed tomography (CT) of the brain. Carotid arteries were categorized by evaluating the degree of stenosis according to North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria, the type of plaque, and the presence of plaque ulceration. The brain was assessed via CT for the presence, type, and position of lesions. Chi-square tests, Student's t test, and simple logistic regression analysis were performed and the Cohen kappa test was applied for interobserver variability measurement.

RESULTS

The Chi-square test indicated a statistically significant association between the presence of fatty plaques (p=0.005) and CT-detectable lesions in the brain (p=0.004). Moreover, the number of patients with CT-detectable brain lesions was greater in patients with >70% stenosis than in those with <70% stenosis (p=0.007). Logistic regression confirmed the association between fatty plaque and symptoms (p=0.001), between >70% stenosis and symptoms (p=0.041), and an inverse association between calcified plaque and symptoms (p=0.009).

CONCLUSION

MDCTA allows adequate evaluation of the type of plaque. The results of the present study indicate that there is an association between cerebral lesions, symptoms, and fatty plaque in the carotid artery. The degree of stenosis also correlated with cerebral lesions and symptoms. According to the obtained data, the type of carotid plaque should be included among primary parameters in the classification of patients' risk class.

Predictive Implications of Recurrent Transient Ischemic Attacks in Large-Artery Atherosclerosis

BACKGROUND

It is uncertain whether recurrent transient ischemic attacks (R-TIAs), when comparing with single TIAs (S-TIAs), have any distinct mechanisms.

METHODS

All consecutive patients with TIAs, who had been admitted for a 2-year period, were divided into two groups: those who had R-TIAs and those who had S-TIAs. Registry data, medical records, and imaging findings were reviewed and compared between the two groups.

RESULTS

There were 85 patients who had TIAs: 42 patients had R-TIAs, and 43 patients had S-TIAs. On univariate analysis, R-TIA patients had less cardiac embolic TIA sources, less weakness, less speech disturbances, shorter symptom duration, a longer time interval from onset to treatment, less abnormalities on diffusion-weighted magnetic resonance imaging, and more significant relevant arterial stenoses. After logistic regression analysis, independent factors associated with R-TIAs were symptom duration < 10 min (odds ratio OR 3.62; 95% confidence interval CI 1.37-9.57), > or = 50% stenosis of the clinically relevant artery (OR 7.08; 95% CI 1.29-38.71), and absence of cardiac embolic sources (OR 0.04; 95% CI 0.002-0.71).

CONCLUSIONS

R-TIAs may have pathophysiological mechanisms distinct from those of S-TIAs and so may provide a clue for the etiologic diagnosis, in that patients with R-TIAs are more likely to have large-artery atherosclerosis.

The FABP2 gene polymorphism in cerebrovascular disease

OBJECTIVE

Earlier studies have shown that the fatty acid binding protein 2 (FABP2) T54 allele is associated with dyslipidemia, which in turn correlates with the incidence of cerebrovascular disease (CVD). To assess whether the FABP2 gene A54T polymorphism is associated with an increased risk of CVD we undertook a case-control study.

MATERIALS AND METHODS

A total of 407 patients diagnosed with acute CVD and 158 control subjects were genotyped for the A54T polymorphism using a PCR-RFLP method.

RESULTS

Allele and genotype frequencies of the FABP2 A54T polymorphism did not differ between subjects with acute CVD (TT, 9.6%; TA, 41.0%; AA, 49.4%) and controls (TT, 7.6%; TA, 41.1%; AA, 51.3%; P = ns) or in the following subgroups of CVD compared with controls: non-cardioembolic infarction (n = 252), intracerebral hemorrhage (n = 23), and cardioembolic infarction (n = 91). In transient ischemic attacks (TIAs) (n = 41) the combined TT and TA genotype frequency (TT + TA, 65.9%) was more frequent than in controls (48.7%) (P = 0.05). Furthermore, the TT genotype was more frequent in non-smoking patients under the age of 70 (n = 77) with a non-cardioembolic infarction (TT, 18.2%) compared with controls (7.6%) (P = 0.024).

CONCLUSIONS

Our findings suggest an involvement of the FABP2 (A54T) gene polymorphism in the pathogenesis of CVD. The FABP2 T54 allele appears to be a genetic susceptibility marker for TIA and non-cardioembolic infarction at younger onset.

Subtyping in ischemic stroke genetic research

Discovery of genes that influence stroke risk might be facilitated if phenotypic heterogeneity of the population studied were reduced by studying individual subtypes of stroke. Standardized systems for classifying stroke are generally mechanistic or syndromic. Mechanistic systems (eg, Trial of ORG10172 in Acute Stroke Treatment) are based on presumed pathophysiologic basis of occlusion. Syndromic systems (eg, Oxfordshire Community Stroke Project) are based on signs and symptoms of neurologic dysfunction. Linkage and candidate gene studies should use such standardized systems in the search for subtype-specific genetic risk factors to increase the validity of interstudy comparisons.

Hemodynamic and metabolic changes in transient ischemic attack patients: a magnetic resonance angiography and (1)H-magnetic resonance spectroscopy study performed within 3 days of onset of a transient ischemic attack

BACKGROUND AND PURPOSE

We investigated whether patients with transient ischemic attack (TIA) have systemic low flow to the brain or an abnormal intracranial flow distribution caused by an abnormal anatomy of the circle of Willis. Furthermore, we investigated whether metabolic changes were present in the brain.

METHODS

Forty-four patients with clinically diagnosed TIA were prospectively included in our study. Clinical and neurological data were compiled. MR imaging; quantitative flow measurements of the internal carotid, middle cerebral, and basilar arteries; MR angiography of the circle of Willis; and (1)H-MR spectroscopy were performed in all patients within 3 days of onset of symptoms.

RESULTS

Compared with control subjects, TIA patients did not have altered flow volume in any of the arteries and had normal flow distribution through the circle of Willis. In TIA patients, the N-acetylaspartate (NAA)/choline ratio in noninfarcted regions was significantly decreased in the symptomatic hemisphere (1.73+/-0.16) compared with the asymptomatic hemisphere (1.84+/-0.19, P<0.05) and control subjects (1.90+/-0.17, P<0.001). In the symptomatic hemisphere, the lactate/NAA ratio was significantly increased (0.04+/-0.08) compared with control subjects (0.00+/-0.01, P<0.05). Patients with a history of prior TIA had a significantly decreased NAA/choline ratio in both the symptomatic (P<0.05) and asymptomatic (P<0.05) hemispheres compared with TIA patients without a prior TIA.

CONCLUSIONS

TIA patients have neurological deficits that are transient; however, metabolic damage to the brain is present up to 3 days after the onset of the symptoms. These metabolic changes are not restricted to the symptomatic hemisphere or to areas close to ischemic lesions.

Lesions visualized by contrast-enhanced magnetic resonance imaging in transient ischemic attacks

In patients with transient ischemic attacks (TIAs), contrast-enhanced magnetic resonance imaging (MRI) is more sensitive to visualize the recent ischemic lesions than conventional MRI. We examined the clinical characteristics of TIA patients presenting with enhanced lesions visualized by contrast-enhanced MRI. We retrospectively evaluated 64 patients with carotid TIAs. We evaluated the frequency and topography of TIA associated infarcts on contrast-enhanced MRI and compared the clinical background of patients with and without such lesions. Twenty-three patients underwent plain MRI only, while the remaining 41 patients underwent contrast-enhanced MRI. Of the latter 41 patients, 16 had abnormal enhanced lesions (39%: group L), while 25 had no lesions (61%: group NL). In group L, all lesions were spotty, and they were located in the cerebral cortex in 13 patients (81%), the subcortex in two (12%), and the perforator territory in one (6%). Aphasia or confusional state, hypertension, and emboligenic cardiac or arterial disease (stenosis > or =50%) were more frequently observed in group L than in group NL (38 vs. 8%, 81 vs. 48%, and 93 vs. 60%, respectively, P<0. 05). The TIA patients with enhanced lesions on MRI may be associated with an emboligenic cardiac or arterial disease, severe neurologic symptom compared to those without them.

Reversal of acute apparent diffusion coefficient abnormalities and delayed neuronal death following transient focal cerebral ischemia in rats

Twenty-two rats were subjected to 8, 15, 30, or 60 minutes of temporary middle cerebral artery occlusion (n = 5 per group) or sham occlusion (n = 2) in the magnetic resonance imaging unit. Diffusion-, perfusion-, and T2-weighted imaging were acquired before and during occlusion, and after reperfusion. A coregistration method was used to correlate the acute changes of the average apparent diffusion coefficient (ADCav) with the histology after 72 hours at the same topographic sites. The initially reduced ADCav values recovered completely in both the lateral caudoputamen and upper frontoparietal cortex in the 8-, 15-, and 30-minute groups, partially in the cortex, and not at all in the caudoputamen in the 60-minute group. The histology showed that the caudoputamen was either normal or had mild neuronal injury in the 8-minute group and invariably had some degree of neuronal death in the 15-, 30-, and 60-minute groups, whereas the cortex was either normal or had varying degrees of neuronal injury in all groups. No histological abnormalities were seen in the sham-operated rats. Our data suggest that acute ADCav reversal does not always predict tissue recovery from ischemic injury and that temporary focal ischemia for even 8-minute duration can cause delayed neuronal death that is more severe in the caudoputamen where the initial ADCav decline was greater than in the cortex.

Prevalence and associations of MRI-demonstrated brain infarcts in elderly subjects with a history of transient ischemic attack. The Cardiovascular Health Study

BACKGROUND AND PURPOSE

MRI is more sensitive than CT, but the significance of brain abnormalities seen on MR images obtained in older subjects with transient ischemic attack (TIA) is not clear. We studied the prevalence and risk factors associated with MRI-demonstrated infarcts in elderly subjects with a history of TIA.

METHODS

Participants of the Cardiovascular Health Study, aged 65 years or more and without prior stroke, were studied with brain MRI (n=3456). The prevalence of brain infarcts (>/=3 mm) on MRI was determined in subjects with and without TIA. The cardiovascular risk factors and clinical and subclinical cardiovascular disease associated with MRI infarcts were studied in subjects with TIA.

RESULTS

Subjects with TIA (n=100) had a higher prevalence of MRI infarcts than subjects without TIA (46% versus 28%; P<0.001). The unadjusted odds ratio for having MRI infarcts in subjects with TIA was 2.20 (95% CI, 1.47 to 3.30) and remained significantly elevated after adjustments for risk factors and cerebrovascular disease (odds ratio, 1.86; 95% CI, 1.23 to 2.83). In subjects with TIA, diastolic blood pressure (P=0.01) and internal carotid artery intima-media thickness (P=0.01) were the only factors predictive of the presence of MRI infarcts by stepwise logistic regression analysis.

CONCLUSIONS

MRI infarcts are imaging manifestations of clinically important cerebrovascular disease in subjects with a history of TIA, given their increased prevalence and positive association with increased diastolic blood pressure and internal carotid artery intima-media thickness.

Computerised tomography findings as a risk factor in carotid endarterectomy: early and late results

OBJECTIVES

To evaluate whether preoperative CT evidence of brain infarction is associated with an increased risk of early and late stroke and death in patients undergoing CEA.

DESIGN

Retrospective clinical study.

MATERIALS AND METHODS

We evaluated 844 CT scanning records from 893 patients undergoing CEA from 1986-1994: 43% (367) CT positive for cerebral infarction and 57% (477) negative. Univariate and multivariate analysis was performed for risk factors and preoperative symptoms in patients with positive and negative CT scans, and Kaplan Meier survival curves for late events.

RESULTS

A positive CT was significantly more frequent in males vs. females (p < 0.0001; O.R. 2.52; C.I. 1.73-3.73), diabetics vs. non-diabetics (p = 0.03; O.R. 1.52; C.I. 1.03-2.26), symptomatics vs. asymptomatics (p < 0.001; O.R. 2; C.I. 1.93-3.53) and contralateral occlusion vs. patency (p < 0.001; O.R. 2; C.I. 1.30-3.10). The perioperative disabling stroke/ death rate was higher in patients with a positive CT (p = 0.002; O.R. 6.27; C.I. 1.73-34.20); in asymptomatic patients this difference was striking (5 patients vs. O, p = 0.0002). Multiple logistic regression analysis for risk factors, CT findings, symptoms preceding surgery, and congruity of brain infarction confirmed a significantly higher incidence of perioperative stroke/death rate (p = 0.003; O.R. 6.37; C.I. 5.12-7.63) and early and late stroke (p = 0.02; O.R. 1.95; C.I. 1.38-2.53) and death (p = 0.0005; O.R. 2.38; C.I. 1.89-2.88) in patients with brain lesions. After 7 years, the survival rate (p = 0.0009) and stroke-free interval (p = 0.003) were lower in patients with a positive CT. After 5 years, in asymptomatic patients the survival rate (p = 0.003) and stroke-free interval (p = 0.01) were lower in the positive CT group.

CONCLUSIONS

A positive CT finding, regardless of congruity of the lesion, should be regarded as an indicator of an increased risk of stroke and death in patients scheduled for carotid surgery, especially in those with asymptomatic stenosis.

Magnetic resonance imaging correlates of transient cerebral ischemic attacks

BACKGROUND AND PURPOSE

MRI of patients with a transient ischemic attack (TIA) may provide more detailed morphological insights than CT. We therefore studied the frequency and type of TIA-related infarcts shown by MRI, examined the utility of intravenous contrast material, and searched for potential predictors of infarct occurrence.

METHODS

We performed 1.5-T MRI of the brain of 52 patients (age range, 28 to 93 years; mean, 61 years) with a hemispheric TIA. Contrast material (Gd-DTPA) was given to 45 individuals. We recorded type, number, size, and location of ischemic brain lesions and related the presence of acute infarction to features of clinical presentation and probable causes for the TIA.

RESULTS

MRI showed focal ischemic lesions in 50 patients (81%), but an acute TIA-associated infarct was seen in only 19 subjects (31%). In patients with an acute lesion, the infarcts were smaller than 1.5 cm in 13 (68%), purely cortical in 11 (58%), and multiple in 7 (37%) individuals. Contrast enhancement contributed to the delineation of an acute lesion in only 2 of 45 patients (4%). Acute infarction was unpredictable by clinical TIA features, but the frequency of identifiable vascular or cardiac causes was significantly higher in those patients with TIA-related morphological damage (odds ratio, 5.2 [95% confidence interval, 1.6 to 17.3]).

CONCLUSIONS

More than two thirds of TIA patients showed no associated brain lesion even when MRI and contrast material were used, but the overall frequency of ischemic damage was high. TIA-related infarcts on MRI were mostly small and limited to the cortex and tended to consist of multiple lesions. A positive MRI underscores the need for comprehensive diagnostic workup since evidence of infarction appears to be associated with a higher frequency of significant vascular or cardiac disorders.

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.

Silent brain infarcts and transient ischemic attacks. A three-year study of first-ever ischemic stroke patients: the Klosterneuburg Stroke Data Bank

BACKGROUND AND PURPOSE

We undertook to study the clinical relevance of silent strokes and history of transient ischemic attacks (TIAs) and their individual and combined effects on outcome variables of neurological and epidemiological interest in first-ever stroke patients.

METHODS

We performed univariate and multivariate analyses of data prospectively collected in the Klosterneuburg Stroke Data Bank, a hospital-based registry in Austria that includes a 3-year follow-up program.

RESULTS

Of 728 patients (mean age, 68 +/- 10 years) with a first-ever ischemic stroke, 110 (15%) had had a previous TIA, and 66/618 (11%) patients did not have a history of TIA but showed evidence of silent brain infarct on CT. Outcome variables of neurological interest were not significantly different between groups, including time between stroke and study entry, activities of daily living status at first presentation, median time of hospitalization, 30-day mortality, or 3-year mortality. Univariate analyses of epidemiologically important risk factors showed either history of TIA or evidence of silent infarct to be more frequently associated with hypertension (P = .007). Cox models of survival showed that neither history of TIA nor evidence of silent infarct were significantly associated with an increase in 3-year mortality.

CONCLUSIONS

Over a period of 3 years, neither history of TIA nor evidence of silent infarct diagnosed at the time of the presenting major stroke in first-ever ischemic stroke patients exert an important influence on neurological or epidemiological outcome variables.

Silent infarction on a second CT scan in 91 patients without manifest stroke in the Dutch TIA trial

The frequency of silent infarction is an important issue because it is a marker of vascular disease. We studied the occurrence of silent infarction in a sample of patients from the Dutch TIA trial, in which patients were randomized between 30 and 283 mg of aspirin. A total of 91 patients with TIA or non-disabling ischemic stroke and who did not suffer a stroke during a period of one to four years (mean 32 months) underwent CT scanning both on entry and at the end of the study. A cardiac source of embolism was an exclusion criterion for the trial. We found only one patient with a possibly silent infarction; in four patients a previously detected symptomatic infarct on CT was no longer visible. The rarity of silent infarction in this study may have several explanations; (1) the relatively short period of follow-up, (2) the selection of patients (no cardiac source of embolism), (3) the clinical monitoring at four monthly intervals aimed at detection of focal ischemia, (4) the use of aspirin. Given these circumstances, silent infarction is an infrequent problem.

Baseline silent cerebral infarction in the Asymptomatic Carotid Atherosclerosis Study

BACKGROUND AND PURPOSE

In a group of patients with high-grade asymptomatic carotid artery stenosis, we prospectively determined the prevalence and radiological characteristics of clinically asymptomatic brain infarction evident on computed tomography. Risk factors and extent of carotid disease were also determined.

METHODS

Patients randomized into the Asymptomatic Carotid Atherosclerosis Study (ACAS) underwent a neurological history, a detailed stroke/transient ischemic attack questionnaire, and a detailed neurological examination. Computed tomography scans were examined by standardized criteria developed as part of a quality-control program supervised by a neuroradiologist. The presence, location, and size of all cerebral infarctions evident by computed tomography were determined.

RESULTS

Among 1132 patients, 848 had no history of stroke or transient ischemic attack. One hundred twenty-six patients (15%) had a silent infarct; 95 (11%) had one, 24 (3%) had two, and 7 (1%) had three or more infarcts. The infarct size was small and deep for 117 patients (72%), less than one-half lobe for 45 (28%), and one-half to less than one lobe for 1 (0.5%). The silent infarcts were evenly distributed ipsilaterally and contralaterally to the study artery but were significantly more frequent in the right hemisphere (P < .05). Factors associated with silent infarction were abnormal gait (P < .001), abnormal deep tendon reflexes or plantar responses (P = .038), but not degree of carotid stenosis. Silent infarction was less frequent among this totally asymptomatic cohort (15%) compared with those with transient ischemic attacks (34/139, 25%; P < .001).

CONCLUSIONS

Silent infarction in the setting of asymptomatic carotid stenosis is not uncommon, but silent infarctions are rarely sizable. The clinical significance of silent cerebral infarction in patients with asymptomatic carotid artery stenosis has yet to be established.

Transient ischemic attacks, risk factors, and precerebral color doppler angiosonography

The aim of this study was to ascertain the importance of color-coded Doppler sonography (CCDS), a noninvasive examination technique, in early detection of atherosclerotic lesions in precerebral arteries. CCDS was utilized in a group of patients with one or several transient ischemic attacks (TIA) and in a group of non-TIA (NTIA) cases, so that the degree of atherosclerotic lesions of precerebral vessies in TIA and NTIA patients might be compared. The presence of risk factors for cerebrovascular disease (CVD) was compared in both groups as well. We examined 87 patients with TIA (38 women and 49 men), aged 19-86 years (mean, 60.97 ± 11.97 years) and 48 NTIA patients (22 women and 26 men), aged 35-85 years (mean,60.04 ± 9.37years). No statistically significant differences in age and gender were found between the groups. A significant difference was found between the common carotid artery intimal-medial thickness (CCA IMT) in TIA patients (CCA IMT right + left = 1.12 ± 0.44 mm) and NTIA patients (CCA IMT right + left = 0.91 ± 0.32 mm) (p < 0.0001). A positive significant association was found between both groups in the number of different plaques (p < 0.0001) and the number of stenoses (p < 0.0001). When risk factors were compared, the difference between TIA and NTIA groups was statistically significant in regard to high-density lipoproteins (p < 0.002), total cholesterol (p < 0.004), and blood glucose concentrations (p < 0.013), as well as systolic blood pressure (p < 0.011). In conclusion, Doppler sonographic changes in precerebral arteries were present in the TIA group in spite of the fact that both groups had identical risk factors for CVD. CCDS is a valuable aid for early detection of TIA patients who have a significant risk of developing brain infarction.

Silent stroke in patients with transient ischemic attack or minor ischemic stroke. The Dutch TIA Trial Study Group

BACKGROUND AND PURPOSE

We studied silent stroke (i.e., infarcts on computed tomographic scan not related to later symptoms) in patients after transient ischemic attack or minor ischemic stroke.

METHODS

Ours is a cross-sectional study of 2,329 patients who were randomized in a secondary prevention trial after transient ischemic attack or minor ischemic stroke and had no residual deficit after the qualifying event.

RESULTS

Silent stroke was observed in 13% of the 2,329 patients. Lacunes formed 79%, cortical lesions 14%, and border zone lesions 7% of all silent strokes. Silent lacunes were most often located in the basal ganglia and symptomatic lacunes most often in the corona radiata. Age, hypertension, and current cigarette smoking were related to the presence of silent stroke. Silent stroke was equally common in different types of transient ischemic attack, including transient monocular blindness. Residual symptoms of any kind were more common in patients with silent stroke than in those without.

CONCLUSIONS

Because only the sites of silent stroke infarcts differed slightly from those of symptomatic infarcts and the frequency of vascular risk factors was similar to that of symptomatic infarcts, silent stroke may have the same bearing on future risk as known prior stroke.

TIA and minor stroke. How to identify and treat patients at risk for recurrent cerebral ischemia

Clinicians should take a mechanistic approach to transient ischemic attack and stroke. Distinguishing between hemorrhagic and ischemic stroke is important and is most readily accomplished with a computed tomographic brain scan. Newer diagnostic studies are now available to help evaluate patients for a cardiogenic source of embolism. Detection of a cardiogenic source of embolism or high-grade carotid stenosis identifies stroke-prone persons in whom interventional therapy is beneficial.