Reduction in early stroke risk in carotid stenosis with transient ischemic attack associated with statin treatment.

BACKGROUND AND PURPOSE: Statins reduce stroke risk when initiated months after transient ischemic attack (TIA)/stroke and reduce early vascular events in acute coronary syndromes, possibly via pleiotropic plaque stabilization. Few data exist on acute statin use in TIA. We aimed to determine whether statin pretreatment at TIA onset modified early stroke risk in carotid stenosis. METHODS: We analyzed data from 2770 patients with TIA from 11 centers, 387 with ipsilateral carotid stenosis. ABCD2 score, abnormal diffusion weighted imaging, medication pretreatment, and early stroke were recorded. RESULTS: In patients with carotid stenosis, 7-day stroke risk was 8.3% (95% confidence interval [CI], 5.7-11.1) compared with 2.7% (CI, 2.0%-3.4%) without stenosis (P<0.0001; 90-day risks 17.8% and 5.7% [P<0.0001]). Among carotid stenosis patients, nonprocedural 7-day stroke risk was 3.8% (CI, 1.2%-9.7%) with statin treatment at TIA onset, compared with 13.2% (CI, 8.5%-19.8%) in those not statin pretreated (P=0.01; 90-day risks 8.9% versus 20.8% [P=0.01]). Statin pretreatment was associated with reduced stroke risk in patients with carotid stenosis (odds ratio for 90-day stroke, 0.37; CI, 0.17-0.82) but not nonstenosis patients (odds ratio, 1.3; CI, 0.8-2.24; P for interaction, 0.008). On multivariable logistic regression, the association remained after adjustment for ABCD2 score, smoking, antiplatelet treatment, recent TIA, and diffusion weighted imaging hyperintensity (adjusted P for interaction, 0.054). CONCLUSIONS: In acute symptomatic carotid stenosis, statin pretreatment was associated with reduced stroke risk, consistent with findings from randomized trials in acute coronary syndromes. These data support the hypothesis that statins started acutely after TIA symptom onset may also be beneficial to prevent early stroke. Randomized trials addressing this question are required.

Systematic review and pooled analysis of published and unpublished validations of the ABCD and ABCD2 transient ischemic attack risk scores.

BACKGROUND AND PURPOSE: The ABCD system was derived to predict early risk of stroke after transient ischemic attack. Independent validations have reported conflicting results. We therefore systematically reviewed published and unpublished data to determine predictive value and generalizability to different clinical settings and users. METHODS: Validations of the ABCD and ABCD2 scores were identified by searching electronic databases, reference lists, relevant journals, and conference abstracts. Unpublished tabulated data were obtained where available. Predictive value, expressed as pooled areas under the receiver operator characteristic curves (AUC), was calculated using random-effects meta-analysis, and analyses for heterogeneity were performed by categorization according to study setting and method. RESULTS: Twenty cohorts were identified reporting the performance of the ABCD system in 9808 subjects with 456 strokes at 7 days. Among the 16 studies of both the ABCD and ABCD2 scores, pooled AUC for the prediction of stroke at 7 days were 0.72 (0.66 to 0.78) and 0.72 (0.63 to 0.82), respectively (P diff=0.97). The pooled AUC for the ABCD and ABCD2 scores in all cohorts reporting relevant data were 0.72 (0.67 to 0.77) and 0.72 (0.63 to 0.80), respectively (both P<0.001). Predictive value varied significantly between studies (P<0.001), but 75% of the variance was accounted for by study method and setting, with the highest pooled AUC for face-to-face clinical evaluation and the lowest for retrospective extraction of data from emergency department records. CONCLUSION: Independent validations of the ABCD system showed good predictive value, with the exception of studies based on retrospective extraction of nonsystematically collected data from emergency department records.

Addition of brain infarction to the ABCD2 Score (ABCD2I): a collaborative analysis of unpublished data on 4574 patients.

BACKGROUND AND PURPOSE: The ABCD system was developed to predict early stroke risk after transient ischemic attack. Incorporation of brain imaging findings has been suggested, but reports have used inconsistent methods and been underpowered. We therefore performed an international, multicenter collaborative study of the prognostic performance of the ABCD(2) score and brain infarction on imaging to determine the optimal weighting of infarction in the score (ABCD(2)I). METHODS: Twelve centers provided unpublished data on ABCD(2) scores, presence of brain infarction on either diffusion-weighted imaging or CT, and follow-up in cohorts of patients with transient ischemic attack diagnosed by World Health Organization criteria. Optimal weighting of infarction in the ABCD(2)I score was determined using area under the receiver operating characteristic curve analyses and random effects meta-analysis. RESULTS: Among 4574 patients with TIA, acute infarction was present in 884 (27.6%) of 3206 imaged with diffusion-weighted imaging and new or old infarction was present in 327 (23.9%) of 1368 imaged with CT. ABCD(2) score and presence of infarction on diffusion-weighted imaging or CT were both independently predictive of stroke (n=145) at 7 days (after adjustment for ABCD(2) score, OR for infarction=6.2, 95% CI=4.2 to 9.0, overall; 14.9, 7.4 to 30.2, for diffusion-weighted imaging; 4.2, 2.6 to 6.9, for CT; all P<0.001). Incorporation of infarction in the ABCD(2)I score improved predictive power with an optimal weighting of 3 points for infarction on CT or diffusion-weighted imaging. Pooled areas under the curve increased from 0.66 (0.53 to 0.78) for the ABCD(2) score to 0.78 (0.72 to 0.85) for the ABCD(2)I score. CONCLUSIONS: In secondary care, incorporation of brain infarction into the ABCD system (ABCD(2)I score) improves prediction of stroke in the acute phase after transient ischemic attack.

Transient ischaemic attack: clinical relevance, risk prediction and urgency of secondary prevention.

PURPOSE OF REVIEW: Transient ischaemic attack (TIA) is increasingly recognized as a harbinger of stroke and an important opportunity for secondary prevention. We have reviewed recent evidence on the burden of TIA and prediction and prevention of stroke in the acute phase. RECENT FINDINGS: Although recent data on the incidence and prevalence of TIA are lacking, available data suggest that the burden of TIA is higher than previously estimated and may be expected to increase with the ageing of the population. Prospective prognostic studies have shown that the early risk of stroke after TIA is approximately 5% at 7 days and 10-15% at 90 days depending on clinical settings and study methodology. This risk can be reliably predicted by risk scores based on clinical features (the ABCD system), TIA aetiology and findings on brain imaging, although the optimal combined prognostic strategy is uncertain because the interaction between individual predictors is not established. Studies of the urgent assessment and initiation of secondary prevention in specialist centres suggest that the early risk of stroke after TIA can be reduced by up to 80%. SUMMARY: The risk of stroke after TIA is considerable. However, recent advances have shown that this risk can be predicted for individuals and substantially reduced by appropriate secondary prevention measures.

Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack.

BACKGROUND: We aimed to validate two similar existing prognostic scores for early risk of stroke after transient ischaemic attack (TIA) and to derive and validate a unified score optimised for prediction of 2-day stroke risk to inform emergency management. METHODS: The California and ABCD scores were validated in four independent groups of patients (n=2893) diagnosed with TIA in emergency departments and clinics in defined populations in the USA and UK. Prognostic value was quantified with c statistics. The two groups used to derive the original scores (n=1916) were used to derive a new unified score based on logistic regression. FINDINGS: The two existing scores predicted the risk of stroke similarly in each of the four validation cohorts, for stroke risks at 2 days, 7 days, and 90 days (c statistics 0.60-0.81). In both derivation groups, c statistics were improved for a unified score based on five factors (age >or=60 years [1 point]; blood pressure >or=140/90 mm Hg [1]; clinical features: unilateral weakness [2], speech impairment without weakness [1]; duration >or=60 min [2] or 10-59 min [1]; and diabetes [1]). This score, ABCD(2), validated well (c statistics 0.62-0.83); overall, 1012 (21%) of patients were classified as high risk (score 6-7, 8.1% 2-day risk), 2169 (45%) as moderate risk (score 4-5, 4.1%), and 1628 (34%) as low risk (score 0-3, 1.0%). IMPLICATIONS: Existing prognostic scores for stroke risk after TIA validate well on multiple independent cohorts, but the unified ABCD(2) score is likely to be most predictive. Patients at high risk need immediate evaluation to optimise stroke prevention.

Effect of urgent treatment of transient ischaemic attack and minor stroke on early recurrent stroke (EXPRESS study): a prospective population-based sequential comparison.

BACKGROUND: The risk of recurrent stroke is up to 10% in the week after a transient ischaemic attack (TIA) or minor stroke. Modelling studies suggest that urgent use of existing preventive treatments could reduce the risk by 80-90%, but in the absence of evidence many health-care systems make little provision. Our aim was to determine the effect of more rapid treatment after TIA and minor stroke in patients who are not admitted direct to hospital. METHODS: We did a prospective before (phase 1: April 1, 2002, to Sept 30, 2004) versus after (phase 2: Oct 1, 2004, to March 31, 2007) study of the effect on process of care and outcome of more urgent assessment and immediate treatment in clinic, rather than subsequent initiation in primary care, in all patients with TIA or minor stroke not admitted direct to hospital. The study was nested within a rigorous population-based incidence study of all TIA and stroke (Oxford Vascular Study; OXVASC), such that case ascertainment, investigation, and follow-up were complete and identical in both periods. The primary outcome was the risk of stroke within 90 days of first seeking medical attention, with independent blinded (to study period) audit of all events. FINDINGS: Of the 1278 patients in OXVASC who presented with TIA or stroke (634 in phase 1 and 644 in phase 2), 607 were referred or presented direct to hospital, 620 were referred for outpatient assessment, and 51 were not referred to secondary care. 95% (n=591) of all outpatient referrals were to the study clinic. Baseline characteristics and delays in seeking medical attention were similar in both periods, but median delay to assessment in the study clinic fell from 3 (IQR 2-5) days in phase 1 to less than 1 (0-3) day in phase 2 (p<0.0001), and median delay to first prescription of treatment fell from 20 (8-53) days to 1 (0-3) day (p<0.0001). The 90-day risk of recurrent stroke in the patients referred to the study clinic was 10.3% (32/310 patients) in phase 1 and 2.1% (6/281 patients) in phase 2 (adjusted hazard ratio 0.20, 95% CI 0.08-0.49; p=0.0001); there was no significant change in risk in patients treated elsewhere. The reduction in risk was independent of age and sex, and early treatment did not increase the risk of intracerebral haemorrhage or other bleeding. INTERPRETATION: Early initiation of existing treatments after TIA or minor stroke was associated with an 80% reduction in the risk of early recurrent stroke. Further follow-up is required to determine long-term outcome, but these results have immediate implications for service provision and public education about TIA and minor stroke.

Risk of stroke early after transient ischaemic attack: a systematic review and meta-analysis.

BACKGROUND: Stroke is often preceded by transient ischaemic attack (TIA), but studies of stroke risk after TIA are logistically difficult and have yielded conflicting results. However, reliable estimation of this risk is necessary for planning effective service provision, clinical trials, and public education. We therefore did a systematic review of all studies of stroke risk early after TIA. METHODS: All studies of stroke risk within 7 days of TIA were identified by use of electronic databases and by hand searches of reference lists, relevant journals, and conference abstracts. Stroke risks at 2 days and 7 days after TIA were calculated overall and analyses for heterogeneity were done, if possible, after categorisation by study method, setting, population, and treatment. FINDINGS: 18 independent cohorts were included, which reported stroke risk in 10 126 TIA patients. The pooled stroke risk was 5.2% (95% CI 3.9-6.5) at 7 days, but there was substantial heterogeneity between studies (p<0.0001), with risks ranging from 0% to 12.8%. However, the risks reported in individual studies over different durations of follow-up were highly correlated (0-7 days vs 8-90 days, r=0.89, p<0.0001), and the heterogeneity between studies was almost fully explained by study method, setting, and treatment. The lowest risks were seen in studies of emergency treatment in specialist stroke services (0.9% [95% CI 0.0-1.9], four studies) and the highest risks in population-based studies without urgent treatment (11.0% [8.6-13.5], three studies). Results were similar for stroke risk at 2 days. INTERPRETATION: The reported early risks of stroke after TIA were highly heterogeneous, but this could be largely accounted for by differences in study method, setting, and treatment, with lowest risks in studies of emergency treatment in specialist stroke services.

Substantial underestimation of the need for outpatient services for TIA and minor stroke.

OBJECTIVES: To measure the number of all transient ischaemic attack (TIAs) and minor strokes managed as outpatients, and hence, the need for 'TIA clinics' in comparison to current estimates of 20,000 TIAs annually in England, based on previous rates of incident-definite events. SUBJECTS: All individuals with confirmed or suspected TIA or stroke between 2002 and 2005 in a population-based study of 91,105 individuals in Oxfordshire, UK. OUTCOME MEASURES: Numbers, rates, and risks of recurrent stroke for incident-definite TIA, any probable or definite TIA, stroke, and all referrals of suspected TIA and stroke, stratified according to inpatient versus outpatient management. RESULTS: Of 1,174 confirmed or suspected events ascertained, 729 (62.1%) were managed as outpatients and 445 (37.9%) as inpatients. Among 757 probable or definite events, 432 (57%) were managed as outpatients. Incident-definite TIAs accounted for only 18% of all referrals to outpatient services. Annual rates per 1,000 population were 2.98 (2.77-3.2) for all referrals to outpatient services and 1.88 (1.71-2.06) for inpatient admissions. Of 73 recurrent strokes within 90 days of initial TIA or stroke, 48 (65.8%) occurred in the outpatient population. Applying these rates to the population of England yields approximately 150,000 new referrals annually to TIA clinics with about 10,000 early recurrent strokes. CONCLUSION: More patients with TIA or stroke are managed as outpatients than inpatients in the UK, and this group has the majority of possibly preventable early recurrent strokes. Current projections of need for TIA clinics in England substantially underestimate the overall requirement for outpatient services.

Patient behavior immediately after transient ischemic attack according to clinical characteristics, perception of the event, and predicted risk of stroke.

BACKGROUND AND PURPOSE: Little research has been done on patients' behavior after transient ischemic attack (TIA). Recent data on the high early risk of stroke after TIA mean that emergency action after TIA is essential for effective secondary prevention. We therefore studied patients' behavior immediately after TIA according to their perceptions, clinical characteristics, and predicted stroke risk. METHODS: Consecutive patients with TIA participating in the Oxford Vascular Study or attending dedicated hospital clinics in Oxfordshire, UK, were interviewed. Predicted stroke risk was calculated using 2 validated scores. RESULTS: Of 241 patients, 107 (44.4%) sought medical attention within hours of the event, although only 24 of these attended the emergency department. A total of 107 (44.4%) delayed seeking medical attention for > or =1 day. Correct recognition of symptoms (42.2% of patients) was not associated with less delay. However, patients with motor symptoms or duration of symptoms > or =1 hour were more likely to seek emergency attention (hazard ratio, 2.1; 95% CI, 1.4 to 3.2; P=0.00005), as were those at higher predicted stroke risk (P=0.001). The other main correlate with delay was the day of the week on which the TIA occurred (P<0.001), with greater delays at the weekend. Delay was unrelated to age, sex, or other vascular risk factors. CONCLUSIONS: Many patients delay seeking medical attention after a TIA irrespective of correct recognition of symptoms, although patients at higher predicted risk of stroke do act more quickly. Public education about both the urgency and nature of TIA is required.

Non-focal neurological symptoms associated with classical presentations of transient ischaemic attack: qualitative analysis of interviews with patients.

BACKGROUND: Improving the recognition of transient ischaemic attack (TIA) at initial healthcare contact is essential as urgent specialist assessment and treatment reduces stroke risk. Accurate TIA detection could be achieved with clinical prediction rules but none have been validated in primary care. An alternative approach using qualitative analysis of patients' experiences of TIA may identify novel features of the TIA phenotype that are not detected routinely, as such techniques have revealed novel early features of other important conditions such as meningococcaemia. We sought to determine whether the patient's experience of TIA would reveal additional deficits that can be tested prospectively in cohort studies to determine their additional diagnostic and prognostic utility at the first healthcare contact. METHODOLOGY AND FINDINGS: Qualitative semi-structured interviews with 25 patients who had experienced definite TIA as determined by a stroke specialist; framework analysis to map symptoms and key words or descriptive phrases used against each individual, with close attention to the detail of the language used. All interview transcripts were reviewed by a specialist clinician with experience in TIA/minor stroke. Patients described non-focal symptoms consistent with higher function deficits in spatial perception and awareness of deficit, as well as feelings of disconnection with their immediate surroundings. Of the classical features, weakness and speech disturbance were described in ways that did not meet the readily recognisable phenotype. CONCLUSION/SIGNIFICANCE: Analysis of patients' narrative accounts reveals a set of overlooked features of the experience of TIA which may provide additional diagnostic utility so that providers of first contact healthcare can recognise TIA more easily. Future research is required in a prospective cohort of patients presenting with transient neurological symptoms to determine how frequent these features are, what they add to diagnostic information and whether they can refine measures to predict stroke risk.

Transient neurological symptoms in the older population: report of a prospective cohort study--the Medical Research Council Cognitive Function and Ageing Study (CFAS).

OBJECTIVE: Transient ischaemic attack (TIA) is a recognised risk factor for stroke in the older population requiring timely assessment and treatment by a specialist. The need for such TIA services is driven by the epidemiology of transient neurological symptoms, which may not be caused by TIA. We report prevalence and incidence of transient neurological symptoms in a large UK cohort study of older people. DESIGN: Longitudinal cohort study SETTING: The Medical Research Council Cognitive Function and Aging Study (CFAS) is a population representative study based on six centres across England and Wales. PARTICIPANTS: Random samples of people in their 65th year were obtained from Family Health Service Authority lists. The participation rate was 80% (n=13 004). Interview at baseline included questions about stroke and three transient neurological symptoms, repeated in a subsample after 2 years. Patients were flagged for mortality. MAIN OUTCOME MEASURES: Prevalence and 2-year incidence of transient neurological symptoms. RESULTS: In 11 903 participants without a history of stroke, 271 (2.3%) reported transient problems with speech, 872 (7.6%) with sight and 596 (5.1%) weakness in a limb with 1456 (12.7%) reporting at least one symptom. Of those reinterviewed (n=6748), 675 (9.8%) reported at least one symptom over 2 years. CONCLUSIONS: Lifetime prevalence and incidence of transient neurological symptoms in people aged 65 years and over is high and is substantially greater than the incidence of TIA in hospital-based and population-based studies. These high rates of transient neurological symptoms in the community in the older population should be considered when planning TIA services.

Addition of brain and carotid imaging to the ABCD² score to identify patients at early risk of stroke after transient ischaemic attack: a multicentre observational study.

BACKGROUND: The ABCD² score improves stratification of patients with transient ischaemic attack by early stroke risk. We aimed to develop two new versions of the score: one that was based on preclinical information and one that was based on imaging and other secondary care assessments. METHODS: We analysed pooled data from patients with clinically defined transient ischaemic attack who were investigated while in secondary care. Items that contribute to the ABCD² score (age, blood pressure, clinical weakness, duration, and diabetes), other clinical variables, carotid stenosis, and abnormal acute diffusion-weighted imaging (DWI) were recorded and were included in multivariate logistic regression analysis of stroke occurrence at early time intervals after onset of transient ischaemic attack. Scores based on the findings of this analysis were validated in patients with transient ischaemic attack from two independent population-based cohorts. FINDINGS: 3886 patients were included in the study: 2654 in the derivation sample and 1232 in the validation sample. We derived the ABCD³ score (range 0-9 points) by assigning 2 points for dual transient ischaemic attack (an earlier transient ischaemic attack within 7 days of the index event). C statistics (which indicate discrimination better than chance at >0·5) for the ABCD³ score were 0·78 at 2 days, 0·80 at 7 days, 0·79 at 28 days, and 0·77 at 90 days, compared with C statistics for the ABCD² score of 0·71 at 2 days (p=0·083), 0·71 at 7 days (p=0·012), 0·71 at 28 days (p=0·021), and 0·69 at 90 days (p=0·018). We included stenosis of at least 50% on carotid imaging (2 points) and abnormal DWI (2 points) in the ABCD³-imaging (ABCD³-I) score (0-13 points). C statistics for the ABCD³-I score were 0·90 at 2 days (compared with ABCD² score p=0·035), 0·92 at 7 days (p=0·001), 0·85 at 28 days (p=0·028), and 0·79 at 90 days (p=0·073). The 90-day net reclassification improvement compared with ABCD² was 29·1% for ABCD³ (p=0·0003) and 39·4% for ABCD³-I (p=0·034). In the validation sample, the ABCD³ and ABCD³-I scores predicted early stroke at 7, 28, and 90 days. However, discrimination and net reclassification of patients with early stroke were similar with ABCD³ compared with ABCD². INTERPRETATION: The ABCD³-I score can improve risk stratification after transient ischaemic attack in secondary care settings. However, use of ABCD³ cannot be recommended without further validation. FUNDING: Health Research Board of Ireland, Irish Heart Foundation, and Irish National Lottery.

Risk prediction after TIA: the ABCD system and other methods.

Transient ischemic attack (TIA) is common in the elderly and total numbers are likely to increase with the aging of the population. The risk of stroke early after TIA has recently been shown to be approximately 5 percent at 7 days and 10 to 15 percent at 3 months, while overall cardiovascular risk is increased in the longer term. The ABCD system (Age, Blood pressure, Clinical features, Duration of symptoms) is a clinical score that can be rapidly worked out at the time of presentation and reliably predicts early risk of stroke. It can be used in patient triage to secondary care, informing public education and in the effective targeting of secondary prevention. The vascular territory and etiology of the TIA and results of cerebral imaging can also be used to predict early risk of stroke but the degree of the interaction between all these factors is uncertain.

Influence of general practice opening hours on delay in seeking medical attention after transient ischaemic attack (TIA) and minor stroke: prospective population based study.

OBJECTIVE: To assess the influence of general practice opening hours on healthcare seeking behaviour after transient ischaemic attack (TIA) and minor stroke and feasibility of clinical assessment within 24 hours of symptom onset. DESIGN: Population based prospective incidence study (Oxford vascular study). SETTING: Nine general practices in Oxfordshire. PARTICIPANTS: 91 000 patients followed from 1 April 2002 to 31 March 2006. MAIN OUTCOME MEASURES: Events that occurred overnight and at weekends (out of hours) and events that occurred during surgery hours. RESULTS: Among 359 patients with TIA and 434 with minor stroke, the median (interquartile range) time to call a general practitioner after an event during surgery hours was 4.0 (1.0-45.5) hours, and 68% of patients with events during surgery hours called within 24 hours of onset of symptoms. Median (interquartile range) time to call a general practitioner after events out of hours was 24.8 (9.0-54.5) hours for patients who waited to contact their registered practice compared with 1.0 (0.3-2.6) hour in those who used an emergency general practitioner service (P<0.001). In patients with events out of hours who waited to see their own general practitioner, seeking attention within 24 hours was considerably less likely for events at weekends than weekdays (odds ratio 0.10, 95% confidence interval 0.05 to 0.21): 70% with events Monday to Friday, 33% on Sundays, and none on Saturdays. Thirteen patients who had events out of hours and did not seek emergency care had a recurrent stroke before they sought medical attention. A primary care centre open 8 am-8 pm seven days a week would have offered cover to 73 patients who waited until surgery hours to call their general practitioner, reducing median delay from 50.1 hours to 4.0 hours in that group and increasing those calling within 24 hours from 34% to 68%. CONCLUSIONS: General practitioners' opening hours influence patients' healthcare seeking behaviour after TIA and minor stroke. Current opening hours can increase delay in assessment. Improved access to primary care and public education about the need for emergency care are required if the relevant targets in the national stroke strategy are to be met.

Prognosis and management in the first few days after a transient ischemic attack or minor ischaemic stroke.

The risk of recurrent stroke during the first few days after a transient ischaemic attack (TIA) or minor stroke is very much higher than previously estimated. However, there is considerable international variation in how patients with suspected TIA or minor stroke are managed in the acute phase, some healthcare systems providing immediate emergency inpatient care and others providing non-emergency outpatient clinic assessment. This review considers what is known about the early prognosis after TIA and minor ischaemic stroke, what factors identify individuals at particularly high early risk of stroke, and what evidence there is that urgent preventive treatment is likely to be effective in reducing the early risk of stroke.

Prediction and prevention of stroke after transient ischemic attack in the short and long term.

Over the last 5 years, a number of studies have shown the early risk of stroke following transient ischemic attack (TIA) to be of the order of 5-10% at 1 week and 10-20% at 3 months, considerably higher than previously estimated. Because these studies have been carried out in a variety of different clinical settings, their findings are likely to be generalizable. Various independent prognostic factors for this early risk of stroke have been identified and models, based on clinical features at presentation, have been derived and validated to predict risk of stroke within 7 and 90 days after TIA. At the same time, diffusion-weighted magnetic resonance imaging and carotid imaging provide prognostic information and are likely to refine risk prediction further, although no unified model combining clinical and imaging data currently exists. Uncertainty continues surrounding the most effective secondary prevention in the hyperacute phase after TIA, especially in the choice of antiplatelet agents, although clinical trials to address this question are ongoing. However, the need for carotid endarterectomy in patients with symptomatic carotid stenosis is well established. The risk of vascular disease in the medium term (1-5 years) following TIA has been more widely studied, and predictive models for this are available. Recent data on the long-term (10 years and beyond) vascular risk after TIA demonstrate ongoing mortality from both cerebrovascular and cardiovascular causes, highlighting the need for continued secondary prevention.

The need for emergency treatment of transient ischemic attack and minor stroke.

The risk of recurrent stroke following transient ischemic attack or minor stroke has recently been shown to be 5-10% at 1 week and 10-20% at 3 months, depending on study population and methods. This is considerably higher than previously estimated and current clinical guidelines reflect the need for rapid assessment although a wide variation in practice exists. Effective management of patients with transient ischemic attack or minor stroke, therefore, requires identification of individuals at the highest (and lowest) risk and initiation of appropriate secondary prevention. Risk can be stratified at initial presentation by the presence or absence of simple clinical features and following subsequent investigation. For transient ischemic attack patients, older age, diabetes, longer duration of symptoms and weakness or speech disturbance identify patients at highest risk, as does the presence of large artery atherosclerosis (mainly internal carotid artery stenosis) and lesions on diffusion-weighted magnetic resonance imaging. Strong evidence exists for the benefit of some early interventions (carotid endarterectomy and antiplatelet agents), but is circumstantial or awaited for others (statins and antihypertensives). In order for the public health challenge posed by transient ischemic attack and minor stroke to be met, considerable change is required in both public education (to ensure correct recognition of symptoms and swift presentation to medical attention) and the provision of clinical services to ensure the timely initiation of effective treatment.