Territory Transient Ischemic Attacks Research Articles

Stroke Mechanisms in Symptomatic Intracranial Atherosclerotic Disease: Classification and Clinical Implications.

Background and Purpose- In patients with symptomatic intracranial atherosclerotic stenosis, identifying the underlying stroke mechanisms may inform secondary prevention. We aimed to propose reproducible classification criteria for stroke mechanisms based on routine neuroimaging in symptomatic intracranial atherosclerotic stenosis and explore their clinical implications. Methods- We recruited patients with acute ischemic stroke attributed to 50% to 99% intracranial atherosclerotic stenosis in anterior circulation from 2 centers. Two investigators independently classified probable stroke mechanisms as parent artery atherosclerosis occluding penetrating artery, artery-to-artery embolism, hypoperfusion, and mixed mechanisms, with prespecified criteria based on infarct topography and magnetic resonance/computed tomography angiography. These stroke mechanisms were correlated with features of the patients at baseline and recurrent ischemic stroke in the same territory or relevant transient ischemic attack within 1 year. Results- Among 153 patients recruited, the most common stroke mechanisms were isolated hypoperfusion (35.3%) and mixed mechanism of artery-to-artery embolism and hypoperfusion (37.3%) that was associated with higher incidence of dyslipidemia (P=0.045) and hypertension (P=0.033) than patients with other stroke mechanisms. The proposed criteria showed substantial to excellent intrarater and interrater reproducibilities (κ, 0.791-0.908). Overall, 31 patients received interventional treatment of the diseased intracranial artery; 122 received medical treatment, among whom a mixed mechanism of artery-to-artery embolism and hypoperfusion at baseline was associated with higher risk of ischemic stroke in the same territory within 1 year (24.4% versus 7.8%; hazard ratio, 3.40; 95% CI, 1.25-9.20; log-rank P=0.010) than other mechanisms combined. Conclusions- Artery-to-artery embolism and hypoperfusion commonly coexist in ischemic stroke attributed to intracranial atherosclerotic stenosis, which may be associated with higher risk of stroke relapse.

Stenting Versus Aggressive Medical Management for Symptomatic Vertebral Artery Stenosis

Posterior circulation strokes account for 20% of all strokes (2). Traditional studies cite a 5-year stroke rate ranging from 22%e 35% following an initial vertebrobasilar transient ischemic attack (TIA) or stroke (11, 14). Contrary to traditional beliefs, the overall risk of recurrent stroke in the posterior circulation is similar to the risk after an anterior circulation stroke, and likely higher in the acute phase (8). In one pooled analysis of 359 patients experiencing vertebrobasilar territory TIA or stroke, the 90-day risk of stroke after the presenting event was 9.6% in patients with vertebrobasilar stenosis versus 2.8% in those without (OR 3.7, 95% CI 1.2e11.0, P 1⁄4 0.012) (9). The authors noted a trend that this risk was higher with intracranial vertebrobasilar stenosis than extracranial vertebral stenosis (P 1⁄4 0.06). To mitigate this risk, aggressive medical management incorporating diet and lifestyle modification, control of hypertension, and the usage of statins and antiplatelet agents may be used (3, 5, 16). In addition, multiple individual case series have suggested that stenting vertebrobasilar lesions may be associated with a low-risk profile and subsequently low rates of referable TIAs or strokes (1, 10, 12, 13, 15). A systematic review of stenting symptomatic, atherosclerotic vertebrobasilar disease reported periprocedural TIA, stroke, and death rates of 1.6%, 1.3%, and 0.3%, respectively, across 313 cases with proximal vertebral artery disease (6). Over a mean follow-up period of 14.2 months, the post-treatment annual rate of TIA or stroke in the vertebrobasilar territory was 0.6%. Interestingly, for 283 cases of distal vertebrobasilar stenting, the periprocedural TIA, stroke, and death rates were 0.7%, 10.6% and 3.2%, respectively (6). The annual rate of subsequent vertebrobasilar stroke over a mean follow-up of 13 months after treatment was 1.9%. Thus although patients with symptomatic intracranial vertebrobasilar stenosis may have a greater risk of TIA or stroke without treatment (9), the risk of stenting may also be higher in this group (6). However, more specifically, a subgroup analysis from the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial demonstrated significantly higher periprocedural ischemic events in patients undergoing stenting of the basilar artery as compared with those undergoing stenting of the intracranial internal carotid, middle cerebral, or vertebral artery (7). Before the Vertebral Artery Stenting Trial (VAST) (3), subgroup analyses of 2 randomized control trials comparing stenting of symptomatic arterial stenosis to best medical management demonstrated no benefit of stenting for patients with vertebral artery stenosis (4, 5). In the Carotid And Vertebral Artery Transluminal Angioplasty Study (CAVATAS), 16 patients with

Clinical analysis of carotid angioplasty stenting for high-grade extracranial carotid artery stenosis combined with severe tortuosity

To observe the feasibility and safety of carotid angioplasty stenting (CAS) for high-grade extracranial carotid artery stenosis combined with severe tortuosity. Twenty patients diagnosed with high-grade extracranial carotid artery stenosis combined with severe tortuosity by cerebral angiography, who were in hospital in neurology department of China-Janpan friendship from June 2011 to June 2014. Twelve of these patients were symptomatic. All cases weren't suit for or disagreed with carotid endarterectomy (CEA) to accept CAS. We retrospectively discussed the rates of technical success, the perioperative complications and clinical improvement. During the follow-up for 4 to 40 months we observed the events of cured carotid artery territory stroke and death, and record the plaque hyperplasia in stent, in-stent restenosis, stent deformation or fracture by color doppler ultrasonography or craniocervical CT angiography. (1) The results of operation: the rate of technical success was 19/20 and the rate of the distal protection device placement was 18/20. One stent and 2 distal protection device were difficult to pass the tortuous access vessels. The kinking was the most common in circuity classification of internal carotid artery. The stenosis was significantly improved after stenting, and the mean degree of stenosis was reduced from (82% ± 9%) before stenting to (7% ± 6%) after stenting. Although 5 patients were with perioperative complications, all symptoms disappeared within 1 weeks, and there was no stent related death and disability. There were 4 cases with vascular spasm, one of them was combined with carotid sinus reaction, and anther with transient ischemic attack (TIA) during operation. There was one with ipsilateral carotid territory minor stroke. (2) The results of prognosis and follow up: The clinical symptoms from 12 symptomatic patients were improved significantly on discharge, and the average NIHSS scores on admission were reduced from (4 ± 4) to (2 ± 2) on discharge. One patient experienced ipsilateral carotid territory minor stroke and another patient experienced ipsilateral carotid territory TIA during the follow-up for an average of 19 months, and there were 5 cases with mild plaque hyperplasia in stent and no in-stent restenosis, stent deformation or fracture. The severe tortuosity of extracranial carotid artery may affect the using of intervention materials and increase the complexity of CAS, but for the patients who disagree with CEA or were with the contraindications to CEA, CAS may be still a relatively safe, effective and alternative treatment.

William M. Feinberg award for excellence in clinical stroke: hemodynamics and stroke risk in carotid artery occlusion.

Five percent to 15% of patients with carotid territory transient ischemic attacks or cerebral infarctions have complete occlusion of the internal carotid artery.1,2 Their risk of recurrent stroke during the next 2 years while on medical therapy is 5% to 9% per year for all stroke and 2% to 8% per year for ipsilateral ischemic stroke.3–6 Debate on the best means to prevent recurrence has centered on whether embolic or hemodynamic mechanisms are most important. In the late 1970s and early 1980s, embolism of atherothrombotic material from the persisting proximal stump of the occluded internal carotid artery through external carotid artery collaterals was put forward as the most common cause for recurrent cerebral ischemic events.7,8 At this same time, extracranial–intracranial (EC-IC) bypass was increasingly used to prevent recurrent stroke by improving the hemodynamic status of the cerebral circulation distal to the occluded vessel.9,10 From 1977 to 1985, an international, multicenter, randomized trial was conducted to determine the efficacy of EC-IC bypass for the prevention of subsequent stroke. Among 808 randomized patients with symptomatic carotid occlusion, no benefit of surgery was demonstrated.11 Some concluded that the reason for the negative results was that the majority of strokes were because of emboli, whereas others criticized the trial for failing to identify patients with hemodynamic cerebral ischemia because of poor collateral circulation for whom surgical revascularization would be of benefit.12,13 However, the pattern of arteriographic collaterals failed to identify a subgroup who benefitted from surgery.14 At the time of the EC-IC Bypass Study, there was no reliable method for assessing the hemodynamic effects of carotid artery occlusion on cerebral circulation. Although direct measurements of arterial-jugular venous oxygen differences had demonstrated that reductions in whole-brain cerebral blood …

Validation of a TIA Recognition Tool in Primary and Secondary Care: Implications for Generalizability

In spite of public education campaigns, patients with transient ischemic attack still present to primary care where accurate recognition of transient ischemic attack is essential so that specialist referral can be expedited to reduce stroke risk. The complex task of diagnosing transient ischemic attack is challenging in time-limited settings in primary care yet the potential for a transient ischemic attack recognition tool to improve diagnosis has not been determined. We set out to examine the potential utility in primary care of the only existing transient ischemic attack recognition tool. All primary care referrals with suspected transient ischemic attack from a total population of 91,000 people were analyzed over a four-year period from 2002 to 2006. Clinical and research records from the transient ischemic attack clinic and consultation notes and referral letters from primary care physicians were used to populate the Dawson recognition score. Of 513 referrals, 209 (47%) had a clinic confirmed diagnosis of transient ischemic attack. Agreement between primary care assessments and specialist assessments was greater for speech disturbance (kappa 0·68) than for unilateral facial weakness (0·58) and unilateral limb weakness (0·51). The Dawson score had greater accuracy in diagnosing all transient ischemic attack in specialist assessments than in primary care assessments (c statistics 0·80 vs. 0·70, P < 0·0001) and performed particularly poorly in primary care for detecting posterior circulation territory transient ischemic attack with a c statistic (95% confidence interval) of 0·52 (0·43-0·61). The Dawson transient ischemic attack recognition score is less accurate in primary care than in its derivation setting of specialist care. Improving the recognition of transient ischemic attack by providers of first contact health care requires derivation of rules in the clinical setting in which they are to be used.

Correlation of ABCD2 Score with Degree of Internal Carotid Artery Stenosis: An Observational Pilot Study

ABCD(2) is a validated scoring system that predicts the risk of stroke after a transient ischemic attack (TIA). International guidelines suggest that patients with a low score can be investigated on an outpatient basis. The ABCD2 score, however, cannot identify which patients have significant internal carotid artery (ICA) disease, and this group of patients could benefit from rapid access carotid endarterectomy (RACE). Studies have shown that patients with significant carotid artery disease have a higher risk of neurologic events or recurrent stroke. The aim of this study was to document the range of ABCD2 scores in patients with carotid artery-related TIA, and investigate any correlation between the ABCD2 scores and ICA stenosis. Patients undergoing carotid duplex ultrasound scan for TIA from January 2009 to May 2010 from two vascular units were identified from the vascular database retrospectively. Clinical notes were reviewed and outcomes measures were recorded: ABCD2 scores (age, blood pressure, clinical features, diabetes, and duration) and carotid plaque morphology. Ninety-seven patients with a mean age of 74 (range 56-90) years had ICA stenoses of ≥50% up to 100%. Fifty-seven patients had an ABCD2 score of ≤4. There was no significant correlation between ABCD2 scores and degree of ICA stenosis nor carotid plaque morphology (P=0.2, r=1.0, and P=1.0, r=0.0007, respectively). Because no correlation between ABCD2 scores and the degree of ICA stenosis was found, all patients with carotid territory TIA should undergo urgent imaging of the carotid arteries because a high proportion of these patients may benefit from RACE.

Middle Cerebral Artery Plaque and Prediction of the Infarction Pattern

Intracranial atherosclerosis is associated with recurrent ischemic stroke. High-resolution magnetic resonance imaging can provide information about atheroma in vivo including plaque volume, composition,and activity. To evaluate atherosclerosis activity of the middle cerebral artery (MCA) by high-resolution magnetic resonance imaging and determine its relationship with infarction patterns. Patients with MCA territory infarction or transient ischemic attack were enrolled and 3-T high resolution magnetic resonance imaging was performed in the relevant MCA. We analyzed the status of the intracranial atheroma and infarction pattern in the corresponding vascular territory. Intracranial atheroma was defined as vulnerable symptomatic plaque when it was accompanied by intraplaque heterogeneous signal intensity and plaque enhancement, and as a stable symptomatic plaque otherwise. Cerebral infarction pattern was defined as artery-to-artery embolic infarction when multiple lesions were present within the MCA territory. A tertiary referral center. A total of 34 patients were enrolled in the study;14 patients had stable symptomatic plaque, 12 had vulnerable symptomatic plaque, and 8 had no plaque (normal group). Intracranial atheroma stability and infarction pattern. High-resolution magnetic resonance images were acquired from 34 patients, which revealed the presence of stable symptomatic plaque in 14 patients and vulnerable symptomatic plaque in 12 patients. The patients with vulnerable symptomatic plaque more commonly demonstrated an artery-to-artery embolic infarction pattern than the patients with stable symptomatic plaque (P=.02). Vulnerable symptomatic plaque as determined by a high-resolution magnetic resonance imaging technique is associated with artery-to-artery embolic infarction.This novel imaging technique can provide information about intracranial atherosclerosis in vivo, which can predict the infarction pattern.

Endovascular management of symptomatic carotid stenosis combined with kinking

To study the necessity, feasibility, security of carotid angioplasty and stenting (CAS) for symptomatic carotid stenosis combined with kinking. Twelve patients with symptomatic carotid stenosis and kinking demonstrated by digital subtraction angiography (DSA) received CAS from December 2003 to December 2009. There were 9 male and 3 female patients, age ranged from 59 to 77 years (mean 69.3 years). All the patients' clinical, imaging, intervention and follow up data were collected and analyzed. All CAS procedures were successfully performed with 14 self-expandable stents placed. The mean degree of stenosis was reduced from 85.6% before stenting to 11.2% after stenting, the angle of kinking, according to Metz' category, were improved from less than 90° to more than 120° in each case. No perioperative procedure related stroke and transient ischemic attack (TIA) occurred. The clinical symptoms and signs of cerebral ischemia were improved or disappeared for all patients. During follow-up of these 12 patients for 6 to 72 months, one patient experienced ipsilateral carotid territory TIA and another patient experienced contralateral carotid territory TIA. DSA follow up of 5 patients demonstrated 1 case with in-stent restenosis and arterial kinking remote to the stent of internal carotid artery. CAS were performed again and CT angiography follow up demonstrated no kinking and restenosis 2 years after the intervention. Duplex scan of the other 7 patients demonstrated neither kinking nor restenosis. CAS seems to be feasible and safe for the patients with symptomatic kinking and stenosis, and maybe helpful to lower the risk of cerebral ischemia, but further study is needed.

Comparison of Methods for Magnetic Resonance-Guided [18-F]Fluorodeoxyglucose Positron Emission Tomography in Human Carotid Arteries

Inflammation is a major risk factor for atherosclerotic plaque rupture and clinical events. Previous studies have shown that plaque [(18)F]fluorodeoxyglucose (FDG) uptake correlates with macrophage content. In this study we examined the reproducibility of 3 methods of quantifying plaque FDG uptake in the carotid arteries using positron emission tomography (PET). The correlation between 2 simplified uptake parameters (standardized uptake value [SUV], vessel wall-to-blood ratio [VBR]) and a gold standard technique (influx rate [K(i)]) was also determined. We used MRI to correct carotid plaque FDG uptake for partial volume error. Seven patients with a recent carotid territory transient ischemic attack underwent imaging twice within 8 days using MR and FDG-PET. MR coregistered to PET was used to delineate regions of interest, and to facilitate partial volume correction (PVC). SUV was the most reproducible parameter irrespective of whether it was normalized by body surface area (BSA), lean body mass, or weight (intraclass correlation coefficient=0.85, 0.88, and 0.90, respectively). VBR correlated better to K(i) than SUV (r=0.58 VBR, r=0.46 SUV(BSA)). PVC improved these correlations to r=0.81 VBR and r=0.76 SUV(BSA), and only slightly degraded the reproducibility of SUV (intraclass correlation coefficient=0.83-0.85). MR-guided FDG-PET is a highly reproducible technique in the carotid artery and the excellent anatomic detail provided by MR facilitates PVC. Of the methods examined, SUV(BSA)(PVC) appears to represent the best compromise between reproducible and accurate determination of FDG metabolism in carotid artery vessel wall.

Accuracy of colored duplex ultrasound diagnosis of spontaneous carotid dissection cause and ischemia

Background and Purpose—Spontaneous dissection of the cervical internal carotid artery (sICAD) is mainly assessed with MRI and magnetic resonance angiography (MRA), which are not always at hand. In contrast, color duplex sonography (CDS) is readily available. We undertook this prospective study to examine the accuracy of CDS to diagnose sICAD in patients with first carotid territory ischemia. Methods—Consecutive patients with first carotid territory stroke or transient ischemic attack or retinal ischemia underwent clinical and laboratory examinations, ECG, CDS of the cerebral arteries, cranial computed tomography in case of stroke or transient ischemic attack, and echocardiography and 24-hour ECG in selected cases. Patients were included, if they were 65 years of age, CDS showed a probable sICAD (cervical internal carotid artery stenosed or occluded), or had no determined etiology of ischemia. All of the included patients underwent cervical MRI and MRA cerebral catheter angiography. The sonographer was blinded to the results of MRI and angiography studies. Results—We included 177 of 1652 screened patients. Excluded patients (n 1475) were 65 years old (n 818), had another determined cause of ischemia (n 1475), and had intracranial hemorrhage (n 58). CDS diagnosed sICAD in 77 of 177 patients, and the etiology of ischemia was undetermined in the remaining 100 patients. Cervical MRI and angiography showed 74 sICAD; there were 6 falsely positive and 3 falsely negative CDS findings. Thus, sensitivity, specificity, and positive and negative predictive values for CDS diagnosis of patients with sICAD causing carotid territory ischemia was 96%, 94%, 92%, and 97%, respectively. Conclusions—Color duplex ultrasound allows the reliable exclusion of sICAD in patients with carotid territory ischemia, whereas diagnosis of CDS of sICAD must be confirmed with cervical MRI and MRA. (Stroke. 2006;37:000-000.)

Accuracy of Color Duplex Ultrasound Diagnosis of Spontaneous Carotid Dissection Causing Ischemia

Spontaneous dissection of the cervical internal carotid artery (sICAD) is mainly assessed with MRI and magnetic resonance angiography (MRA), which are not always at hand. In contrast, color duplex sonography (CDS) is readily available. We undertook this prospective study to examine the accuracy of CDS to diagnose sICAD in patients with first carotid territory ischemia. Consecutive patients with first carotid territory stroke or transient ischemic attack or retinal ischemia underwent clinical and laboratory examinations, ECG, CDS of the cerebral arteries, cranial computed tomography in case of stroke or transient ischemic attack, and echocardiography and 24-hour ECG in selected cases. Patients were included, if they were <65 years of age, CDS showed a probable sICAD (cervical internal carotid artery stenosed or occluded), or had no determined etiology of ischemia. All of the included patients underwent cervical MRI and MRA+/-cerebral catheter angiography. The sonographer was blinded to the results of MRI and angiography studies. We included 177 of 1652 screened patients. Excluded patients (n=1475) were > or =65 years old (n=818), had another determined cause of ischemia (n=1475), and had intracranial hemorrhage (n=58). CDS diagnosed sICAD in 77 of 177 patients, and the etiology of ischemia was undetermined in the remaining 100 patients. Cervical MRI and angiography showed 74 sICAD; there were 6 falsely positive and 3 falsely negative CDS findings. Thus, sensitivity, specificity, and positive and negative predictive values for CDS diagnosis of patients with sICAD causing carotid territory ischemia was 96%, 94%, 92%, and 97%, respectively. Color duplex ultrasound allows the reliable exclusion of sICAD in patients with carotid territory ischemia, whereas diagnosis of CDS of sICAD must be confirmed with cervical MRI and MRA.

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Prognosis of vertebrobasilar transient ischaemic attack and minor stroke.

Vertebrobasilar (VB) territory transient ischaemic attacks (TIAs) and minor strokes are perceived to have a better prognosis than carotid territory events, and are sometimes managed less aggressively. However, this notion stems mainly from a few small studies in the 1960s and 1970s, and has not been systematically tested. We therefore identified all published studies of prognosis after TIA or minor stroke using MEDLINE and EMBASE, and hand-searching reference lists and relevant journals. In addition, we attempted to include all available individual patient data (IPD) from studies that had not published outcome data by territory of presenting event. Odds of recurrent events were calculated within studies and combined by fixed-effects meta-analysis. Heterogeneity between studies was calculated using the chi2 method. We stratified the analysis by time interval between presenting event and inclusion in study, and by study setting (population-based, published hospital-based and unpublished hospital-based). Publication bias was tested for by linear regression of the standard normal deviate against precision. Eight hundred and twenty abstracts were reviewed, and 304 papers were considered in detail. Of these, 43 studies representing 36 independent cohorts (12,196 patients) reported outcomes by territory of presenting event. IPD from five studies (4643 patients) were also included. The following results compare relative risks of VB with carotid events. Studies including the acute phase (up to 7 days) after the presenting event found a higher relative risk of subsequent stroke in patients with VB events [odds ratio (OR) 1.47, 95% confidence interval (CI) 1.1-2.0, P = 0.014]. Conversely, studies mainly recruiting after the acute phase found a lower relative risk (OR 0.74, 95% CI 0.7-0.8, P = 0.00001). In published hospital-based studies, the risk of recurrent stroke was lower for patients presenting with VB events (OR 0.68, 95% CI 0.6-0.8, P < 0.00001). However, there was no difference in hospital-based IPD (OR 1.02, 95% CI 0.8-1.3, P = 0.91). Moreover, in population-based studies, patients with VB events had a higher risk of stroke (OR 1.48, 95% CI 1.1-2.0, P = 0.025). There was no within-stratum heterogeneity. There was no difference in the risk of fatal stroke (OR 1.04, 95% CI 0.8-1.4, P = 0.90). Therefore, we found no evidence that patients presenting with VB events have a lower risk of subsequent stroke or death compared with patients presenting with carotid TIA or minor stroke. Indeed, their risk of stroke is probably higher in the acute phase. Patients with VB events require active preventive treatment.

Risks of Stroke and Current Indications for Cerebral Revascularization in Patients with Carotid Occlusion

Preventing further stroke in patients with complete carotid artery occlusion remains a difficult challenge because there is no therapy proven effective for this prevention. These patients comprise approximately 15% of patients with carotid artery territory transient ischemic attacks or infarction. Patients with symptomatic carotid artery occlusion have an overall risk of subsequent stroke of 7% per year and a risk of stroke ipsilateral to the occluded carotid artery of 5.9% per year. The presence of severe hemodynamic failure demonstrated by increased oxygen extraction fraction (OEF) of the brain, in a cerebral hemisphere distal to a symptomatic occluded carotid artery, is an independent predictor of subsequent ischemic stroke with a risk comparable to that seen in medically treated patients with symptomatic severe carotid artery stenosis.

Transient ischaemic attacks related to carotid stenosis precipitated by straining, bending, and sneezing

Three patients are described in whom one or more carotid territory transient ischaemic attacks (TIAs) were preceded by sneezing, straining, or bending over. It is argued that the mechanism involved...

A follow‐up survey of clinical practices for the use of heparin, warfarin, and aspirin

To determine whether anticoagulation practices have changed when heparin and warfarin are used to treat cerebrovascular disease, and to determine the dosage of aspirin used to treat carotid territory transient ischemic attacks (TIAs). A 1987 study documented that neurologists and neurology house officers were using excessive amounts of heparin and warfarin. Recent studies have demonstrated the efficacy and safety of low-intensity anticoagulation for preventing strokes, but no data are available on how these findings have affected the treatment practices of clinicians. Questionnaires were sent to neurology staff at 10 medical centers. The questions dealt with the use of heparin, warfarin, and aspirin in stroke/transient ischemic attack patients. The nonparametric Wilcoxon rank sum test was used for analyzing the responses. Ninety-three physicians responded compared with 52 in the prior study. Most (56 of 92; 61%) did not use an IV heparin bolus. The mean partial thromboplastin time (PTT) was 55 seconds, which was significantly less than the mean PTT of 62 seconds (p = 0.006) in the prior study. The mean prothrombin time (PT) fell to 16.0 seconds (range, 12.5 to 20.0) compared with a mean of 19.9 seconds (range, 15.0 to 27.0; p < 0.001) in the earlier study. There was a significant fall in the mean PT ratio from 1.74 (range, 1.20 to 2.25) to 1.49 (range, 1.12 to 2.50; p < 0.001). Most respondents used 325 mg qd of aspirin for treating TIAs. At the centers studied, neurologists and neurology house officers are using less intense anticoagulation when treating stroke patients now than in 1986. This concurs with recent studies demonstrating the efficacy and safety of low-intensity anticoagulation in some clinical settings. The use of 325 mg/d of aspirin is common, although the data supporting its efficacy compared with higher doses are unclear.

High frequency of asymptomatic visual field defects in subjects with transient ischaemic attacks or minor strokes

The hypothesis that asymptomatic visual field defects can be found in patients with carotid transient ischaemic attacks (TIA) or minor strokes was tested. Twenty-two consecutive male patients with TIA and 18 patients with minor strokes from the carotid artery territory were examined by perimetry, cerebral computerised tomography and regional cerebral blood flow. Asymptomatic visual field defects were found in many TIA and minor stroke patients, 29% (5/17) and 57% (8/14), respectively (NS). Eighty-five per cent (11/13) of the scotomas were solely or predominantly located in the upper part of the visual field (P = 0.008 for absolute defects and P = 0.03 for relative defects). We conclude that both carotid territory TIA and minor stroke patients have a high frequency of asymptomatic visual field defects, predominantly located in the upper part of the visual field.

Differences in blood viscosity, glycosylated hemoglobin and platelet count between male patients with carotid territory transient ischemic attacks and minor strokes

Differences in blood viscosity, glycosylated hemoglobin and platelet count between male patients with carotid territory transient ischemic attacks and minor strokes

Symptomatic carotid ischaemic events: safest and most cost effective way of selecting patients for angiography, before carotid endarterectomy.

To determine the safest, least costly, and most effective way to select patients with symptomatic carotid ischaemic events for carotid angiography before carotid endarterectomy. Prospective cohort study. University departments of clinical neurosciences and clinical neurology. 485 Patients with carotid territory transient ischaemic attacks of the brain (n = 224) or eye (n = 162) or retinal infarction (n = 99) were referred to a single neurologist between 1976 and 1986. Clinical examination by auscultation over the precordium, supraclavicular fossae, and neck vessels (all patients). Cerebral angiography of patients suitable for carotid endarterectomy. Financial cost and number of disabling strokes after angiography. 296 Patients were investigated by cerebral angiography. Ischaemic symptoms had occurred in the distribution of 298 internal carotid arteries (symptomatic) that were imaged, two patients having bilateral symptoms. The presence or absence of a carotid bruit and the maximum percentage diameter stenosis of the origin of the symptomatic internal carotid artery were correlated. The prevalence of mild disease (diameter stenosis greater than or equal to 25%) of the symptomatic internal carotid artery was 57%, and if an ipsilateral carotid bruit was heard the probability of mild stenosis rose to 92%. The prevalence of moderate disease of the symptomatic internal carotid artery (stenosis greater than or equal to 50%) was 39%, and if a bruit was heard the probability doubled to 78%. The prevalence of severe internal carotid disease (stenosis greater than or equal to 75%) was 22%, and if a bruit was heard the probability was more than double, at 49%. The direct cost to both the NHS and the private health sector of investigating patients with symptomatic carotid ischaemia was estimated for several strategies of carotid artery imaging and expressed in terms of financial cost and number of strokes after angiography incurred in detecting all patients with diameter stenosis of the symptomatic internal carotid artery of greater than or equal to 25%, 50%, or 75%. To detect diameter stenosis of the internal carotid artery of greater than or equal to 25% it is most cost effective to proceed directly to cerebral angiography in patients with a carotid bruit over the symptomatic carotid bifurcation and to screen patients without a carotid bruit by duplex carotid ultrasonography; patients in whom duplex ultrasonography discloses stenosis of greater than or equal to 25% are then referred for cerebral angiography. To detect only more severe internal carotid disease (stenosis of greater than or equal to 50%) the same policy applies, unless the local duplex ultrasonographic service is particularly efficient and reliable, when it is probably most cost effective and safer to screen all patients by this method irrespective of the findings on cervical auscultation. To detect stenosis of 75% or greater it is most cost effective to screen all patients with duplex ultrasonography, whether a carotid bruit is present or not, because this approach reduces the number of angiograms required, is the least expensive, and results in the least number of strokes after angiography. Patients selection for cerebral angiography before carotid endarterectomy needs to be appropriate and cost effective. Sound clinical evaluation and duplex carotid ultrasound are required. The findings of this study should not be applied to other medical centres without first considering possible differences in the prevalence of carotid artery disease, the efficiency and reliability of duplex ultrasonography, the local complication rates of cerebral angiography, and the local costs of the imaging procedures.

Intraoperative duplex scanning after carotid artery reconstruction: a valuable tool.

The operative management of extracranial cerebrovascular occlusive disease requires meticulous surgical technique. Intraoperative duplex imaging (10 MHz B-mode ultrasound combined with 7.5 MHz Doppler spectrum analysis) was used in an attempt to recognize technical problems that might result in serious neurologic injury. Eighty-four carotid arteries were studied in 76 consecutive patients undergoing carotid endarterectomy or reconstruction. Indications for operation included carotid territory transient ischemic attack (n = 36 [43%]), amaurosis fugax (n = 16 [19%]), stroke (n = 11 [13%]), asymptomatic stenosis (n = 11 [13%]), vertebrobasilar transient ischemic attack (n = 7 [8%]), recurrent stenosis (n = 2 [2%]), and trauma (n = 1 [1%]). Arterial anatomy was assessed ultrasonographically and duplex-derived velocity measurements were obtained to assess hemodynamics. Increased velocity measurement was noted to correlate with ultrasound image of stenosis. Technical errors were identified in 17 patients (22%), including six persons with residual internal carotid artery stenoses, three persons with hemodynamically significant stenoses caused by "kinked" internal carotid arteries, eight persons with debris or intimal flaps in their external carotid arteries, and one person with an occluded external carotid artery. The intraoperative duplex scan led to corrective measures during the surgical procedure in eight patients (11%). No new ipsilateral brain injury was noted in the 76 patients postoperatively. Intraoperative duplex scanning accurately identified residual stenosis, intraluminal thrombus, and loose debris. Duplex scanning altered intraoperative decision making in a significant proportion of patients studied.