Objective To estimate the very early stroke risk after a transient ischaemic attack (TIA) or minor stroke and thereby inform the planning of effective stroke prevention services. Design Population based prospective cohort study of patients with TIA or stroke. Setting Nine general practices in Oxfordshire, England, from April 2002 to April 2003. Participants All patients who had a TIA (n = 87) or minor stroke (n = 87) during the study period and who presented to medical attention. Main outcome measures Risk of recurrent stroke at seven days, one month, and three months after TIAs and minor strokes. Results The estimated risk of recurrent stroke was 8.0% (95% confidence interval 2.3% to 13.7%) at seven days, 11.5% (4.8% to 18.2%) at one month, and 17.3% (9.3% to 25.3%) at three months after a TIA. The risks at these three time periods after a minor stroke were 11.5% (4.8% to 11.2%), 15.0% (7.5% to 22.5%), and 18.5% (10.3% to 26.7%). Conclusions The early risks of stroke after a TIA or minor stroke are much higher than commonly quoted. More research is needed to determine whether these risks can be reduced by more rapid instigation of preventive treatment.

The risk of early recurrent stroke is highest in patients with LAA. This supports the need for urgent carotid imaging and prompt endarterectomy.

Background-Atherosclerotic plaque at the carotid bifurcation is often associated with transient ischemic attack (TIA) and ischemic stroke, but the mechanisms are not completely understood. Previous histological studies have been too small or insufficiently detailed to reliably determine the temporal course of features of plaque instability or to stratify analyses by the nature of presenting symptoms. Methods and Results-We performed the largest-ever histological study of symptomatic carotid plaques from consecutive patients (nϭ526) undergoing endarterectomy and related detailed reproducible histological assessments to the nature and timing of presenting symptoms. There was a high prevalence of many features of coronary-type plaque instability. Dense plaque inflammation (especially infiltration with macrophages) was the feature most strongly associated with both cap rupture (odds ratio 3.39, 95% confidence interval 2.31 to 4.98, PϽ0.001) and time since stroke (Pϭ0.001). Strong negative associations with time since stroke were also seen for cap rupture (Pϭ0.02), overall plaque inflammation (Pϭ0.003), and "unstable plaque" (Pϭ0.001). Although plaques removed Յ60 days after the most recent event were more unstable after a stroke than after a TIA, the instability persisted after a TIA, and plaques removed Ͼ180 days after most recent event were less unstable after a stroke than after a TIA (plaque inflammation: Յ60 days, odds ratio 2. correlations between macrophage infiltration and plaque instability. The tendency for plaque inflammation and overall instability to persist with time after a TIA but to decrease with time after a stroke suggests that the nature of the underlying pathology may differ.

Background and Purpose-The commonly quoted early risks of stroke after a first transient ischemic attack (TIA)-1% to 2% at 7 days and 2% to 4% at 1 month-are likely to be underestimates because of the delay before inclusion into previous studies and the exclusion of patients who had a stroke during this time. Therefore, it is uncertain how urgently TIA patients should be assessed. We used data from the Oxford Community Stroke Project (OCSP) to estimate the very early stroke risk after a TIA and investigated the potential effects of the delays before specialist assessment. Methods-All OCSP patients who had a first-ever definite TIA during the study period (nϭ209) were included. Three analyses were used to estimate the early stroke risk after a first TIA starting from 3 different dates: assessment by a neurologist, referral to the TIA service, and onset of first TIA. Results-The stroke risk from assessment by a neurologist was 1.9% [95% confidence interval (CI), 0.1 to 3.8] at 7 days and 4.4% (95% CI, 1.6 to 7.2) at 30 days. The 7-and 30-day stroke risks from referral were 2.4% (95% CI, 0.3 to 4.5) and 4.9% (95% CI, 1.9 to 7.8), respectively, and from onset of first-ever TIA were 8.6% (95% CI, 4.8 to 12.4) and 12.0% (95% CI, 7.6 to 16.4), respectively. Conclusions-The early risk of stroke from date of first-ever TIA is likely to be higher than commonly quoted. Public education about the symptoms of TIA is needed so that medical attention is sought more urgently and stroke prevention strategies are implemented sooner. (Stroke. 2003;34:e138-e142.)Key Words: cerebral ischemia, transient Ⅲ stroke Ⅲ stroke prevention A pproximately 15% of ischemic strokes are preceded by a transient ischemic attack (TIA). 1 Guidelines highlight the need for rapid-access TIA clinics, 2-4 but it is uncertain how urgently patients must be seen, and there is great variation in practice. 5 The danger of delaying investigation and treatment after a TIA depends on the early risk of stroke. Risks of 1% to 2% at 7 days and 2% to 4% at 1 month are usually quoted. 1,4 However, these are likely to be underestimates because of the delay before patients were included into previous hospital-based studies and clinical trials. Any patients who had a major stroke during this period were excluded.A recent study of patients presenting to an emergency department, almost all of whom were enrolled within 24 hours of the TIA, reported a stroke risk of 5.3% at 2 days. 6 However, this population was self-selected, and there are no equivalent data from populationbased studies. In contrast to stroke incidence and prognosis studies, population-based studies of TIA are scarce. 7 One early populationbased TIA incidence study provided some information on the risk of stroke from the date of TIA, but the analysis was based on retrospective case-note review, and some patients did not come under observation until several years after their TIA. 8 The only population-based prospective TIA incidence study that followed up patients and that satisfies the criteria for a hig...

Background-Carotid angiographic plaque surface morphology is a powerful risk factor for stroke and systemic vascular risk. However, the underlying pathology is unclear, and a better understanding is required both to evaluate other forms of carotid imaging and to develop new treatments. Previous studies comparing angiographic plaque surface morphology with pathology have been small and unblinded, and the vast majority assessed only the crude macroscopic appearance of the plaque. We performed the first large study comparing angiographic surface morphology with detailed histology. Methods and Results-Carotid plaque surface morphology was classified as ulcerated, irregular, or smooth on 128 conventional selective carotid artery angiograms from consecutive patients undergoing endarterectomy for severe symptomatic stenosis. Blinded angiographic assessments were compared with 10 histological features recorded on detailed microscopy of the plaque using reproducible semiquantitative scales. Angiographic ulceration was associated with plaque rupture (Pϭ0.001), intraplaque hemorrhage (Pϭ0.001), large lipid core (Pϭ0.005), less fibrous tissue (Pϭ0.003), and increased instability overall (Pϭ0.001). For example, angiographically ulcerated plaques were much more likely than smooth plaques to be ruptured (ORϭ15.4, 95% CIϭ2.7 to 87.3, PϽ0.001), show a large lipid core (ORϭ26.7, 95% CIϭ2.6 to 270, PϽ0.001) or a large hemorrhage (ORϭ17.0, 95% CIϭ2.0 to 147, Pϭ0.02). The equivalent odds ratios for angiographically irregular versus smooth plaque were 6.3 (1.3 to 31, Pϭ0.02), 6.7 (1.5 to 30, Pϭ0.008), and 9.2 (1.1 to 77, Pϭ0.02), respectively. Conclusions-In contrast to previous studies based on macroscopic assessment, we found very strong associations between detailed histology and carotid angiographic plaque surface morphology. Plaque surface morphology on carotid angiography is a highly sensitive marker of plaque instability. Studies of the predictive value of MR-and CT-based lumen contrast plaque surface imaging are required.