Long-Term Premorbid Blood Pressure and Cerebral Small Vessel Disease Burden on Imaging in Transient Ischemic Attack and Ischemic Stroke.

Background and Purpose- Studies of causes of cerebral small vessel disease (SVD) should fully adjust for blood pressure (BP), but most etiological studies use a single BP measurement or history of hypertension, which might underestimate the role of hypertension. In patients with transient ischemic attack and ischemic stroke, we therefore compared the associations of baseline and long-term premorbid BP with measures of SVD on magnetic resonance imaging brain. Methods- We studied 1009 transient ischemic attack/ischemic stroke patients who had a brain magnetic resonance imaging, in the population-based OXVASC (Oxford Vascular Study), and related baseline and 20-year premorbid BP (median: 15 readings/patient) to the total SVD score on imaging. Results- SVD score was associated with increasing mean baseline systolic BP (SBP; odds ratio of top versus bottom BP quartile: 2.28; [95% CI, 1.62-3.21]; P<0.0001) and with prior hypertension (2.53; [95% CI, 2.01-3.20]; P<0.0001), but the association was much stronger with mean premorbid SBP (6.09; [95% CI, 4.34-8.55]; P<0.0001). Mean diastolic BP at baseline was negatively associated with SVD score (0.71; [95% CI, 0.51-1.00]; P=0.050), and a positive association was only evident for diastolic BP 10 to 20 years previously (3.35; [95% CI, 2.33-4.84]; both P<0.0001). Relationships between overall mean premorbid BP and SVD burden were strongest in patients age <70 (SBP: 6.99; 4.11-11.86; diastolic BP: 3.13; 1.95-5.07; both P<0.0001) versus ≥70 years (2.37; 1.42-3.94; P=0.001; and 1.16; 0.74-1.84; P=0.52). Conclusions- Mean premorbid SBP is more strongly associated with SVD burden than baseline SBP or history of hypertension, and baseline diastolic BP yields a misleading estimate of the likely etiological importance of midlife hypertension for the subsequent development of SVD. Studies of novel potential etiological factors for SVD should aim to adjust for long-term prior BP, and trials of BP lowering with only a few years of follow-up may underestimate the overall impact on SVD.

Medical Attention Seeking After Transient Ischemic Attack and Minor Stroke Before and After the UK Face, Arm, Speech, Time (FAST) Public Education Campaign: Results From the Oxford Vascular Study.

Importance: Risk of major stroke is high during the hours and days after transient ischemic attack (TIA) and minor stroke but is substantially reduced by urgent medical treatment. Public education campaigns have improved the response after major stroke, but their association with behavior after TIA and minor stroke is uncertain. The number of potentially preventable early recurrent strokes in patients who delay or fail to seek medical attention is unknown. Objective: To investigate the association of public education with delays and failure in seeking medical attention after TIA and minor stroke. Design, Setting, and Participants: Prospective population-based study of all patients with TIA or stroke who sought medical attention between April 1, 2002, and March 31, 2014, registered at 9 general practices in Oxfordshire, United Kingdom. Data analysis took place from July 1, 2013, to March 2, 2015. Exposures: Face, Arm, Speech, Time (FAST) public education campaign in the United Kingdom. Main Outcomes and Measures: Number of early recurrent strokes in patients who delayed or failed to seek medical attention, as well as the odds of seeking urgent attention after TIA and minor stroke before vs after initiation of the public education campaign. Results: Among 2243 consecutive patients with first TIA or stroke (mean [SD] age, 73.6 [13.4] years; 1126 [50.2%] female; 96.3% of white race/ethnicity), 1656 (73.8%) had a minor stroke or TIA. After the FAST campaign, patients with major stroke more often sought medical attention within 3 hours (odds ratio [OR], 2.56; 95% CI, 1.11-5.90; P = .03). For TIA and minor stroke, there was no improvement in use of emergency medical services (OR, 0.79; 95% CI, 0.50-1.23; P for interaction = .03 vs major stroke) or time to first seeking medical attention within 24 hours (OR, 0.75; 95% CI, 0.48-1.19; P for interaction = .006 vs major stroke). Patient perception of symptoms after TIA and minor stroke was associated with more urgent behavior, but correct perception declined after the FAST campaign (from 37.3% [289 of 774] to 27.6% [178 of 645]; OR, 0.64; 95% CI, 0.51-0.80; P < .001). One hundred eighty-eight patients had a stroke within 90 days of their initial TIA or stroke, of whom 93 (49.5%) followed unheeded TIAs for which no medical attention was sought, similar before and after the FAST campaign (43 of 538 [8.0%] before vs 50 of 615 [8.1%] after, P = .93). Conclusions and Relevance: This study suggests that in contrast to major stroke, extensive FAST-based public education has not improved the response to TIA and minor stroke in the United Kingdom, emphasizing the need for campaigns that are tailored to transient and less severe symptoms.

Effects of aspirin on risks of vascular events and cancer according to bodyweight and dose: analysis of individual patient data from randomised trials.

BACKGROUND: A one-dose-fits-all approach to use of aspirin has yielded only modest benefits in long-term prevention of cardiovascular events, possibly due to underdosing in patients of large body size and excess dosing in patients of small body size, which might also affect other outcomes. METHODS: Using individual patient data, we analysed the modifying effects of bodyweight (10 kg bands) and height (10 cm bands) on the effects of low doses (≤100 mg) and higher doses (300-325 mg or ≥500 mg) of aspirin in randomised trials of aspirin in primary prevention of cardiovascular events. We stratified the findings by age, sex, and vascular risk factors, and validated them in trials of aspirin in secondary prevention of stroke. Additionally, we assessed whether any weight or height dependence was evident for the effect of aspirin on 20-year risk of colorectal cancer or any in-trial cancer. RESULTS: Among ten eligible trials of aspirin in primary prevention (including 117 279 participants), bodyweight varied four-fold and trial median weight ranged from 60·0 kg to 81·2 kg (p<0·0001). The ability of 75-100 mg aspirin to reduce cardiovascular events decreased with increasing weight (pinteraction=0·0072), with benefit seen in people weighing 50-69 kg (hazard ratio [HR] 0·75 [95% CI 0·65-0·85]) but not in those weighing 70 kg or more (0·95 [0·86-1·04]; 1·09 [0·93-1·29] for vascular death). Furthermore, the case fatality of a first cardiovascular event was increased by low-dose aspirin in people weighing 70 kg or more (odds ratio 1·33 [95% CI 1·08-1·64], p=0·0082). Higher doses of aspirin (≥325 mg) had the opposite interaction with bodyweight (difference pinteraction=0·0013), reducing cardiovascular events only at higher weight (pinteraction=0·017). Findings were similar in men and women, in people with diabetes, in trials of aspirin in secondary prevention, and in relation to height (pinteraction=0·0025 for cardiovascular events). Aspirin-mediated reductions in long-term risk of colorectal cancer were also weight dependent (pinteraction=0·038). Stratification by body size also revealed harms due to excess dosing: risk of sudden death was increased by aspirin in people at low weight for dose (pinteraction=0·0018) and risk of all-cause death was increased in people weighing less than 50 kg who were receiving 75-100 mg aspirin (HR 1·52 [95% CI 1·04-2·21], p=0·031). In participants aged 70 years or older, the 3-year risk of cancer was also increased by aspirin (1·20 [1·03-1·47], p=0·02), particularly in those weighing less than 70 kg (1·31 [1·07-1·61], p=0·009) and consequently in women (1·44 [1·11-1·87], p=0·0069). INTERPRETATION: Low doses of aspirin (75-100 mg) were only effective in preventing vascular events in patients weighing less than 70 kg, and had no benefit in the 80% of men and nearly 50% of all women weighing 70 kg or more. By contrast, higher doses of aspirin were only effective in patients weighing 70 kg or more. Given that aspirin's effects on other outcomes, including cancer, also showed interactions with body size, a one-dose-fits-all approach to aspirin is unlikely to be optimal, and a more tailored strategy is required. FUNDING: Wellcome Trust and National Institute for Health Research Oxford Biomedical Research Centre.

Time course of blood pressure control prior to lacunar TIA and stroke: Population-based study.

OBJECTIVE: To determine the age-specific temporal trends in blood pressure (BP) before acute lacunar vs nonlacunar TIA and stroke. METHODS: In a population-based study of TIA/ischemic stroke (Oxford Vascular Study), we studied 15-year premorbid BP readings from primary care records in patients with lacunar vs nonlacunar events (Trial of Org 10172 in Acute Stroke Treatment [TOAST]) stratified by age (<65, ≥65 years). RESULTS: Of 2,085 patients (1,250 with stroke, 835 with TIA), 309 had lacunar events. In 493 patients <65 years of age, the prevalence of diagnosed hypertension did not differ between lacunar and nonlacunar events (46 [48.4%] vs 164 [41.2%], p = 0.20), but mean/SD premorbid BP (44,496 BP readings) was higher in patients with lacunar events (15-year records: systolic BP [SBP] 138.5/17.7 vs 133.3/15.0 mm Hg, p = 0.004; diastolic BP [DBP] 84.1/9.6 vs 80.9/8.4 mm Hg, p = 0.001), mainly because of higher mean BP during the 5 years before the event (SBP 142.6/18.8 vs 134.6/16.6 mm Hg, p = 0.0001; DBP 85.2/9.7 vs 80.6/9.0 mm Hg, p < 0.0001), with a rising trend (ptrend = 0.006) toward higher BP leading up to the event (<30-day pre-event SBP: 152.7/16.1 vs 135.3/23.1 mm Hg, p = 0.009; DBP 87.9/9.4 vs 80.8/12.8 mm Hg, p = 0.05; mean BP ≤1 year before the event 145.8/22.0 vs 134.7/16.1 mm Hg, p = 0.001; 86.1/10.7 vs 80.4/9.8 mm Hg, p = 0.0001). Maximum BP in the 5 years before the event was also higher in patients with lacunar events (SBP 173.7/26.6 vs 158.6/23.2 mm Hg, p = 0.0001; DBP 102.3/12.9 vs 94.2/11.2 mm Hg, p < 0.0001), as was persistently elevated BP (≥50% SBP >160 mm Hg, odd ratio 4.95, 95% confidence interval 1.99-12.31, p = 0.0002). However, no similar differences in BP were observed in patients ≥65 years of age. CONCLUSION: Recent premorbid BP control is strongly temporarily related to acute lacunar events at younger ages, suggesting a direct role of BP in accelerating causal pathology and highlighting the need to control hypertension quickly.

Age-specific risks, severity, time course, and outcome of bleeding on long-term antiplatelet treatment after vascular events: a population-based cohort study.

BACKGROUND: Lifelong antiplatelet treatment is recommended after ischaemic vascular events, on the basis of trials done mainly in patients younger than 75 years. Upper gastrointestinal bleeding is a serious complication, but had low case fatality in trials of aspirin and is not generally thought to cause long-term disability. Consequently, although co-prescription of proton-pump inhibitors (PPIs) reduces upper gastrointestinal bleeds by 70-90%, uptake is low and guidelines are conflicting. We aimed to assess the risk, time course, and outcomes of bleeding on antiplatelet treatment for secondary prevention in patients of all ages. METHODS: We did a prospective population-based cohort study in patients with a first transient ischaemic attack, ischaemic stroke, or myocardial infarction treated with antiplatelet drugs (mainly aspirin based, without routine PPI use) after the event in the Oxford Vascular Study from 2002 to 2012, with follow-up until 2013. We determined type, severity, outcome (disability or death), and time course of bleeding requiring medical attention by face-to-face follow-up for 10 years. We estimated age-specific numbers needed to treat (NNT) to prevent upper gastrointestinal bleeding with routine PPI co-prescription on the basis of Kaplan-Meier risk estimates and relative risk reduction estimates from previous trials. FINDINGS: 3166 patients (1582 [50%] aged ≥75 years) had 405 first bleeding events (n=218 gastrointestinal, n=45 intracranial, and n=142 other) during 13 509 patient-years of follow-up. Of the 314 patients (78%) with bleeds admitted to hospital, 117 (37%) were missed by administrative coding. Risk of non-major bleeding was unrelated to age, but major bleeding increased steeply with age (≥75 years hazard ratio [HR] 3·10, 95% CI 2·27-4·24; p<0·0001), particularly for fatal bleeds (5·53, 2·65-11·54; p<0·0001), and was sustained during long-term follow-up. The same was true of major upper gastrointestinal bleeds (≥75 years HR 4·13, 2·60-6·57; p<0·0001), particularly if disabling or fatal (10·26, 4·37-24·13; p<0·0001). At age 75 years or older, major upper gastrointestinal bleeds were mostly disabling or fatal (45 [62%] of 73 patients vs 101 [47%] of 213 patients with recurrent ischaemic stroke), and outnumbered disabling or fatal intracerebral haemorrhage (n=45 vs n=18), with an absolute risk of 9·15 (95% CI 6·67-12·24) per 1000 patient-years. The estimated NNT for routine PPI use to prevent one disabling or fatal upper gastrointestinal bleed over 5 years fell from 338 for individuals younger than 65 years, to 25 for individuals aged 85 years or older. INTERPRETATION: In patients receiving aspirin-based antiplatelet treatment without routine PPI use, the long-term risk of major bleeding is higher and more sustained in older patients in practice than in the younger patients in previous trials, with a substantial risk of disabling or fatal upper gastrointestinal bleeding. Given that half of the major bleeds in patients aged 75 years or older were upper gastrointestinal, the estimated NNT for routine PPI use to prevent such bleeds is low, and co-prescription should be encouraged. FUNDING: Wellcome Trust, Wolfson Foundation, British Heart Foundation, Dunhill Medical Trust, National Institute of Health Research (NIHR), and the NIHR Oxford Biomedical Research Centre.

Time Course of Evolution of Disability and Cause-Specific Mortality After Ischemic Stroke: Implications for Trial Design.

BACKGROUND: Outcome in stroke trials is often based on a 3-month modified Rankin scale (mRS). How 3-month mRS relates to longer-term outcomes will depend on late recovery, delayed stroke-related deaths, recurrent strokes, and nonstroke deaths. We evaluated 3-month mRS and death/disability at 1 and 5 years in a population-based cohort study. METHODS AND RESULTS: In 3-month survivors of ischemic stroke (Oxford Vascular Study; 2002-2014), we related 3-month mRS to disability (defined as mRS >2) at 1 and 5 years and/or death rates (age/sex adjusted). Accrual of disability and index-stroke-related and nonstroke deaths in each poststroke year was categorized according to 3-month mRS. Among 1606 patients with acute ischemic stroke, 181 died within 3 months, but 126 index-stroke-related deaths and 320 other deaths occurred during the subsequent 4866 patient-years of follow-up up to 5 years. Although 69/126 (54.8%) post-3-month index-stroke-related deaths occurred after 1 year, mRS>2 at 1 year strongly predicted these deaths (adjusted hazard ratio=21.94, 95%CI 7.88-61.09, P<0.0001). Consequently, a 3-month mRS >2 was a strong independent predictor of death at both 1 year (adjusted hazard ratio=6.67, 95%CI 4.16-10.69, P<0.0001) and 5 years (adjusted hazard ratio=2.93, 95%CI 2.38-3.60, P<0.0001). Although mRS improved by ≥1 point from 3 months to 1 year in 317/1266 (25.0%) patients with 3-month mRS ≥1, improvement in mRS after 1 year was limited (improvement by ≥1 point: 91/858 [10.6%]; improvement to mRS ≤2: 13/353 [3.7%]). CONCLUSIONS: Our results reaffirm use of the 3-month mRS outcome in stroke trials. Although later recovery does occur, extending follow-up to 1 year would capture most long-term stroke-related disability. However, administrative mortality follow-up beyond 1 year has the potential to demonstrate translation of early disability gains into additional reductions in long-term mortality without much erosion by non-stroke-related deaths.

Recent time trends in incidence, outcome and premorbid treatment of atrial fibrillation-related stroke and other embolic vascular events: a population-based study.

BACKGROUND: Prevalence of atrial fibrillation (AF) is increasing, due partly to the ageing population. The Birmingham Atrial Fibrillation Treatment of the Aged (BAFTA) Trial, published in 2007, provided strong evidence of the effectiveness of warfarin at age≥80 years, but the impact on incidence of AF-related stroke and peripheral embolic vascular events is uncertain. METHODS: We studied age-specific incidence and outcome of all AF-related incident strokes and systemic emboli from 2002 to 2012 in the Oxford Vascular Study. RESULTS: Of 3096 acute cerebral or peripheral vascular events, 748 (24.2%) were AF-related. Of the 597 disabling/fatal incident ischaemic strokes, 369 occurred at age ≥80 years, of which 124 (33.6%) were in non-anticoagulated patients with known prior AF. There was no reduction in incident AF-related events after 2007 at all ages (n=231 vs 211; adjusted RR=1.11, 0.91 to 1.36, p=0.29) or at age ≥80 (137 vs 135, RR=1.15, 0.94 to 1.40, p=0.17). Scope for improved prevention at older ages was considerable. Among 208 patients with incident AF-related events at age ≥80 and known prior AF, only 19 (9.1%) were anticoagulated. Of the 189 patients not anticoagulated, 166 (87.8%) had no major disability prior to the event and 167 (88·4%) had a high embolism risk score, of whom 139 (83.2%) were also at low risk of complications. Yet, 125/167 (74.9%) were dead or institutionalised after the event. Potentially preventable embolic events outnumbered warfarin-related intracerebral haemorrhages by about 15-fold (280 vs 19), rising to 50-fold (189 vs 4) at age ≥80 years. CONCLUSIONS: We found no reduction in incidence of AF-related vascular events since publication of the BAFTA trial. A third of all disabling/fatal strokes occur in non-anticoagulated patients with known prior AF.

Blood Pressure and Risk of Vascular Dementia: Evidence From a Primary Care Registry and a Cohort Study of Transient Ischemic Attack and Stroke.

BACKGROUND AND PURPOSE: Vascular dementia is the second most common form of dementia but reliable evidence on age-specific associations between blood pressure (BP) and risk of vascular dementia is limited and some studies have reported negative associations at older ages. METHODS: In a cohort of 4.28 million individuals, free of known vascular disease and dementia and identified from linked electronic primary care health records in the United Kingdom (Clinical Practice Research Datalink), we related BP to time to physician-diagnosed vascular dementia. We further determined associations between BP and dementia in a prospective population-based cohort of incident transient ischemic attack and stroke (Oxford Vascular Study). RESULTS: For a median follow-up of 7.0 years, 11 114 initial presentations of vascular dementia were observed in the primary care cohort after exclusion of the first 4 years of follow-up. The association between usual systolic BP and risk of vascular dementia decreased with age (hazard ratio per 20 mm Hg higher systolic BP, 1.62; 95% confidence interval, 1.13-2.35 at 30-50 years; 1.26, 1.18-1.35 at 51-70 years; 0.97, 0.92-1.03 at 71-90 years; P trend=0.006). Usual systolic BP remained predictive of vascular dementia after accounting for effect mediation by stroke and transient ischemic attack. In the population-based cohort, prior systolic BP was predictive of 5-year risk of dementia with no evidence of negative association at older ages. CONCLUSIONS: BP is positively associated with risk of vascular dementia, irrespective of preceding transient ischemic attack or stroke. Previous reports of inverse associations in old age could not be confirmed.

Effects of aspirin on risk and severity of early recurrent stroke after transient ischaemic attack and ischaemic stroke: time-course analysis of randomised trials.

BACKGROUND: Aspirin is recommended for secondary prevention after transient ischaemic attack (TIA) or ischaemic stroke on the basis of trials showing a 13% reduction in long-term risk of recurrent stroke. However, the risk of major stroke is very high for only the first few days after TIA and minor ischaemic stroke, and observational studies show substantially greater benefits of early medical treatment in the acute phase than do longer-term trials. We hypothesised that the short-term benefits of early aspirin have been underestimated. METHODS: Pooling the individual patient data from all randomised trials of aspirin versus control in secondary prevention after TIA or ischaemic stroke, we studied the effects of aspirin on the risk and severity of recurrent stroke, stratified by the following time periods: less than 6 weeks, 6-12 weeks, and more than 12 weeks after randomisation. We compared the severity of early recurrent strokes between treatment groups with shift analysis of modified Rankin Scale (mRS) score. To understand possible mechanisms of action, we also studied the time course of the interaction between effects of aspirin and dipyridamole in secondary prevention of stroke. In a further analysis we pooled data from trials of aspirin versus control in which patients were randomised less than 48 h after major acute stroke, stratified by severity of baseline neurological deficit, to establish the very early time course of the effect of aspirin on risk of recurrent ischaemic stroke and how this differs by severity at baseline. FINDINGS: We pooled data for 15,778 participants from 12 trials of aspirin versus control in secondary prevention. Aspirin reduced the 6 week risk of recurrent ischaemic stroke by about 60% (84 of 8452 participants in the aspirin group had an ischaemic stroke vs 175 of 7326; hazard ratio [HR] 0·42, 95% CI 0·32-0·55, p<0·0001) and disabling or fatal ischaemic stroke by about 70% (36 of 8452 vs 110 of 7326; 0·29, 0·20-0·42, p<0·0001), with greatest benefit noted in patients presenting with TIA or minor stroke (at 0-2 weeks, two of 6691 participants in the aspirin group with TIA or minor stroke had a disabling or fatal ischaemic stroke vs 23 of 5726 in the control group, HR 0·07, 95% CI 0·02-0·31, p=0·0004; at 0-6 weeks, 14 vs 60 participants, 0·19, 0·11-0·34, p<0·0001). The effect of aspirin on early recurrent ischaemic stroke was due partly to a substantial reduction in severity (mRS shift analysis odds ratio [OR] 0·42, 0·26-0·70, p=0·0007). These effects were independent of dose, patient characteristics, or aetiology of TIA or stroke. Some further reduction in risk of ischaemic stroke accrued for aspirin only versus control from 6-12 weeks, but there was no benefit after 12 weeks (stroke risk OR 0·97, 0·84-1·12, p=0·67; severity mRS shift OR 1·00, 0·77-1·29, p=0·97). By contrast, dipyridamole plus aspirin versus aspirin alone had no effect on risk or severity of recurrent ischaemic stroke within 12 weeks (OR 0·90, 95% CI 0·65-1·25, p=0·53; mRS shift OR 0·90, 0·37-1·72, p=0·99), but dipyridamole did reduce risk thereafter (0·76, 0·63-0·92, p=0·005), particularly of disabling or fatal ischaemic stroke (0·64, 0·49-0·84, p=0·0010). We pooled data for 40,531 participants from three trials of aspirin versus control in major acute stroke. The reduction in risk of recurrent ischaemic stroke at 14 days was most evident in patients with less severe baseline deficits, and was substantial by the second day after starting treatment (2-3 day HR 0·37, 95% CI 0·25-0·57, p<0·0001). INTERPRETATION: Our findings confirm that medical treatment substantially reduces the risk of early recurrent stroke after TIA and minor stroke and identify aspirin as the key intervention. The considerable early benefit from aspirin warrants public education about self-administration after possible TIA. The previously unrecognised effect of aspirin on severity of early recurrent stroke, the diminishing benefit with longer-term use, and the contrasting time course of effects of dipyridamole have implications for understanding mechanisms of action. FUNDING: Wellcome Trust, the National Institute of Health Research (NIHR) Biomedical Research Centre, Oxford.

Delirium risk stratification in consecutive unselected admissions to acute medicine: validation of externally derived risk scores.

BACKGROUND: reliable delirium risk stratification will aid recognition, anticipation and prevention and will facilitate targeting of resources in clinical practice as well as identification of at-risk patients for research. Delirium risk scores have been derived for acute medicine, but none has been prospectively validated in external cohorts. We therefore aimed to determine the reliability of externally derived risk scores in a consecutive cohort of older acute medicine patients. METHODS: consecutive patients aged ≥65 over two 8-week periods (2010, 2012) were screened prospectively for delirium using the Confusion Assessment Method (CAM), and delirium was diagnosed using the DSM IV criteria. The reliability of existing delirium risk scores derived in acute medicine cohorts and simplified for use in routine clinical practice (USA, n = 2; Spain, n = 1; Indonesia, n = 1) was determined by the area under the receiver operating characteristic curve (AUC). Delirium was defined as prevalent (on admission), incident (occurring during admission) and any (prevalent + incident) delirium. RESULTS: among 308 consecutive patients aged ≥65 (mean age/SD = 81/8 years, 164 (54%) female), existing delirium risk scores had AUCs for delirium similar to those reported in their original internal validations ranging from 0.69 to 0.76 for any delirium and 0.73 to 0.83 for incident delirium. All scores performed better than chance but no one score was clearly superior. CONCLUSIONS: externally derived delirium risk scores performed well in our independent acute medicine population with reliability unaffected by simplification and might therefore facilitate targeting of multicomponent interventions in routine clinical practice.

Methodological Factors in Determining Risk of Dementia After Transient Ischemic Attack and Stroke: (III) Applicability of Cognitive Tests.

BACKGROUND AND PURPOSE: Cognitive assessment is recommended after stroke but there are few data on the applicability of short cognitive tests to the full spectrum of patients. We therefore determined the rates, causes, and associates of untestability in a population-based study of all transient ischemic attack (TIA) and stroke. METHODS: Patients with TIA or stroke prospectively recruited (2002-2007) into the Oxford Vascular Study had ≥1 short cognitive test (mini-mental state examination, telephone interview of cognitive status, Montreal cognitive assessment, and abbreviated mental test score) at baseline and on follow-up to 5 years. RESULTS: Among 1097 consecutive assessed survivors (mean: age/SD, 74.8/12.1 years; 378 TIA), numbers testable with a short cognitive test at baseline, 1, 6, 12, and 60 months were 835/1097 (76%), 778/947 (82%), 756/857 (88%), 692/792 (87%), and 472/567 (83%). Eighty-eight percent (331/378) of assessed patients with TIA were testable at baseline compared with only 46% (133/290) of major stroke (P<0.001). Untestability was also associated with older age, premorbid dependency, death on follow-up, and with both pre- and postevent dementia (all P<0.01). Untestability (and problems with testing) were commonly caused by acute stroke effects at baseline (153/262 [58%]: dysphasia/anarthria/hemiparesis=84 [32%], drowsiness=58 [22%], and acute confusion=11 [4%]), whereas sensory deficits caused relatively more problems with testing at later time points (24/63 [38%] at 5 years). CONCLUSIONS: Substantial numbers of patients with TIA and stroke are untestable with short cognitive tests. Future studies should report data on untestable patients and those with problems with testing in whom the likelihood of dementia is high.

Copeptin and Long-Term Risk of Recurrent Vascular Events After Transient Ischemic Attack and Ischemic Stroke: Population-Based Study.

BACKGROUND AND PURPOSE: Copeptin, the c-terminal portion of provasopressin, is a useful prognostic marker in patients after myocardial infarction and heart failure. More recently, high levels of copeptin have also been associated with worse functional outcome and increased mortality within the first year after ischemic stroke and transient ischemic attack (TIA). However, to date, there are no published data on whether copeptin predicts long-term risk of vascular events after TIA and stroke. METHODS: We measured copeptin levels in consecutive patients with TIA or ischemic stroke in a population-based study (Oxford Vascular Study) recruited from 2002 to 2007 and followed up to 2014. Associations with risk of recurrent vascular events were determined by Cox-regression. RESULTS: During ≈6000 patient-years in 1076 patients, there were 357 recurrent vascular events, including 174 ischemic strokes. After adjustment for age, sex, and risk factors, copeptin was predictive of recurrent vascular events (adjusted hazard ratio per SD, 1.47; 95% confidence interval, 1.31-1.64; P=0.0001), vascular death (1.85; 1.60-2.14; P<0.0001), all-cause death (1.75; 1.58-1.93; P<0.0001), and recurrent ischemic stroke (1.22; 1.04-1.44; P=0.017); and improved model-discrimination significantly: net reclassification improvement for recurrent vascular events (32%; P<0.0001), vascular death (55%; P<0.0001), death (66%; P<0.0001), and recurrent stroke (16%; P=0.044). The predictive value of copeptin was largest in patients with cardioembolic index events (adjusted hazard ratio, 1.84; 95% confidence interval, 1.53-2.20 versus 1.31, 1.14-1.50 in noncardioembolic stroke; P=0.0025). In patients with cardioembolic stroke, high copeptin levels were associated with a 4-fold increased risk of vascular events within the first year of follow-up (adjusted hazard ratio, 4.02; 95% confidence interval, 2.13-7.70). CONCLUSIONS: In patients with TIA and ischemic stroke, copeptin predicted recurrent vascular events and death, particularly after cardioembolic TIA/stroke. Further validation is required, in particular, in studies using more extensive cardiac evaluation.

Incidence, outcome, risk factors, and long-term prognosis of cryptogenic transient ischaemic attack and ischaemic stroke: a population-based study.

BACKGROUND: A third of transient ischaemic attacks (TIAs) and ischaemic strokes are of undetermined cause (ie, cryptogenic), potentially undermining secondary prevention. If these events are due to occult atheroma, the risk-factor profile and coronary prognosis should resemble that of overt large artery events. If they have a cardioembolic cause, the risk of future cardioembolic events should be increased. We aimed to assess the burden, outcome, risk factors, and long-term prognosis of cryptogenic TIA and stroke. METHODS: In a population-based study in Oxfordshire, UK, among patients with a first TIA or ischaemic stroke from April 1, 2002, to March 31, 2014, we compared cryptogenic events versus other causative subtypes according to the TOAST classification. We compared markers of atherosclerosis (ie, risk factors, coronary and peripheral arterial disease, asymptomatic carotid stenosis, and 10-year risk of acute coronary events) and of cardioembolism (ie, risk of cardioembolic stroke, systemic emboli, and new atrial fibrillation [AF] during follow-up, and minor-risk echocardiographic abnormalities and subclinical paroxysmal AF at baseline in patients with index events between 2010 and 2014). FINDINGS: Among 2555 patients, 812 (32%) had cryptogenic events (incidence of cryptogenic stroke 0·36 per 1000 population per year, 95% CI 0·23-0·49). Death or dependency at 6 months was similar after cryptogenic stroke compared with non-cardioembolic stroke (23% vs 27% for large artery and small vessel subtypes combined; p=0·26) as was the 10-year risk of recurrence (32% vs 27%; p=0·91). However, the cryptogenic group had fewer atherosclerotic risk factors than the large artery disease (p<0·0001), small vessel disease (p=0·001), and cardioembolic (p=0·008) groups. Compared with patients with large artery events, those with cryptogenic events had less hypertension (adjusted odds ratio [OR] 0·41, 95% CI 0·30-0·56; p<0·0001), diabetes (0·62, 0·43-0·90; p=0·01), peripheral vascular disease (0·27, 0·17-0·45; p<0·0001), hypercholesterolaemia (0·53, 0·40-0·70; p<0·0001), and history of smoking (0·68, 0·51-0·92; p=0·01), and compared with small vessel and cardioembolic subtypes, they had no excess risk of asymptomatic carotid disease (adjusted OR 0·64, 95% CI 0·37-1·11; p=0·11) or acute coronary events (adjusted hazard ratio [HR] 0·76, 95% CI 0·49-1·18; p=0·22) during follow-up. Compared with large artery and small vessel subtypes combined, patients with cryptogenic events also had no excess of minor-risk echocardiographic abnormalities (cryptogenic 37% vs 45%; p=0·18) or paroxysmal AF (6% vs 10%; p=0·17) at baseline or of new AF (adjusted HR 1·23, 0·78-1·95; p=0·37) or presumed cardioembolic events (1·16, 0·62-2·17; p=0·64) during follow-up. INTERPRETATION: The clinical burden of cryptogenic TIA and stroke is substantial. Although stroke recurrence rates are comparable with other subtypes, cryptogenic events have the fewest atherosclerotic markers and no excess of cardioembolic markers. FUNDING: Wellcome Trust, Wolfson Foundation, UK Stroke Association, British Heart Foundation, Dunhill Medical Trust, National Institute for Health Research, Medical Research Council, and the NIHR Oxford Biomedical Research Centre.

Methodological Factors in Determining Risk of Dementia After Transient Ischemic Attack and Stroke: (II) Effect of Attrition on Follow-Up.

BACKGROUND AND PURPOSE: Cognitive outcomes in cohorts and trials are often based only on face-to-face clinic assessment. However, cognitive impairment is strongly associated with increased morbidity and mortality, leading to substantial loss to clinic follow-up. In the absence of previous population-based data, we determined the effect of such attrition on measured risk of dementia after transient ischemic attack and stroke. METHODS: Patients with transient ischemic attack or stroke prospectively recruited (2002-2007) into the Oxford Vascular (OXVASC) study had baseline clinical/cognitive assessment and follow-up to 2014. Dementia was diagnosed through face-to-face clinic interview, supplemented by home visits and telephone assessment in patients unable to attend clinic and by hand-searching of primary care records in uncontactable patients. RESULTS: Of 1236 patients (mean age/SD, 75.2/12.1 years; 582 men), 527 (43%) died by 5-year follow-up. Follow-up assessment rates (study clinic, home visit, or telephone) of survivors were 947 in 1026 (92%), 857 in 958 (89%), 792 in 915 (87%), and 567 in 673 (84%) at 1, 6, 12 months and 5 years. Dementia developed in 260 patients, of whom 110 (42%; n=50 primary care records, n=49 home visit, and n=11 telephone follow-up) had not been available for face-to-face clinic follow-up at the time of diagnosis. The 5-year cumulative incidence of postevent dementia was 29% (26%-32%) overall but was only 17% (14% to 19%) in clinic assessed versus 45% (39%-51%) in nonclinic-assessed patients (P difference<0.001). CONCLUSIONS: Exclusion of patients unavailable for clinic follow-up reduces the measured risk of postevent dementia. Use of multiple follow-up methods, including home visits, telephone assessments, and consent, to access primary care records substantially increases ascertainment of longer-term dementia outcomes.

Biomarkers and mortality after transient ischemic attack and minor ischemic stroke: population-based study.

BACKGROUND AND PURPOSE: Premature death after transient ischemic attack or stroke is more often because of heart disease or cancer than stroke. Previous studies found blood biomarkers not usefully predictive of nonfatal stroke but possibly of all-cause death. This association might be explained by potentially treatable occult cardiac disease or cancer. We therefore aimed to validate the association of a panel of biomarkers with all-cause death, particularly cardiac death and cancer death, despite the absence of associations with risk of nonfatal vascular events. METHODS: Fifteen biomarkers were measured in 929 consecutive patients in a population-based study (Oxford Vascular Study), recruited from 2002 and followed up to 2013. Associations were determined by Cox regression. Model discrimination was assessed by c-statistic and the integrated discrimination improvement. RESULTS: During 5560 patient-years of follow-up, none of the biomarkers predicted risk of nonfatal vascular events. However, soluble tumor necrosis factor α receptor-1, von Willebrand factor, heart-type fatty-acid-binding protein, and N-terminal pro-B-type natriuretic peptide were independently predictive of all-cause death (n=361; adjusted hazard ratio per SD, 95% confidence interval: heart-type fatty-acid-binding protein: 1.31, 1.12-1.56, P=0.002; N-terminal pro-B-type natriuretic peptide: 1.34, 1.11-1.62, P=0.002; soluble tumor necrosis factor α receptor-1: 1.45, 1.26-1.66, P=0.02; von Willebrand factor: 1.19, 1.04-1.36, P=0.01). The independent contribution of the four biomarkers taken together added prognostic information and improved model discrimination (integrated discrimination improvement=0.028, P=0.0001). N-terminal pro-B-type natriuretic peptide was most predictive of vascular death (adjusted hazard ratio=1.80, 95% confidence interval, 1.34-2.41, P<0.0001), whereas heart-type fatty-acid-binding protein predicted cancer deaths (1.64, 1.26-2.12, P=0.0002). Associations were strongest in patients without known prior cardiac disease or cancer. CONCLUSIONS: Several biomarkers predicted death of any cause after transient ischemic attack and minor stroke. N-terminal pro-B-type natriuretic peptide and heart-type fatty-acid-binding protein might improve patient selection for additional screening for occult cardiac disease or cancer, respectively. However, our results require validation in future studies.

Methodological factors in determining rates of dementia in transient ischemic attack and stroke: (I) impact of baseline selection bias.

BACKGROUND AND PURPOSE: Many previous studies on dementia in stroke have restrictive inclusion criteria, which may result in underestimation of dementia rates. We undertook a large prospective population-based study of all transient ischemic attack and stroke to determine the impact of study entry criteria on measured rates of pre- and postevent dementia. METHODS: All patients with acute transient ischemic attack or stroke from a defined population of 92 728 are referred from primary care or at hospital admission to the Oxford Vascular Study (2002-2007) and have baseline clinical and cognitive assessment and follow-up. We examined the impact of early death, other nonavailability, and commonly used selection criteria, on measured rates of dementia. RESULTS: Among 1236 patients (mean age/SD 75.2/12.1 years, 582 men, 403 transient ischemic attack), 139 died or were otherwise unavailable for baseline assessment, 319 had prior dependency, 425 had comorbidity, 512 were aged ≥80 years, 85 were dysphasic, and 502 were hospitalized. Pre-event dementia was 3-fold higher in patients dying preascertainment (10/47, 21%) and twice as high in other nonassessed (14/92, 15%) versus assessed patients (69/1097, 6%; P=0.0006 and P=0.002) and was several-fold higher in those with prior functional impairment (24% versus 3%; P<0.0001), age >80 years (13% versus 3%; P<0.0001), dysphasia (11% versus 7%; P<0.0001), and comorbidity (10% versus 6%; P=0.04). Findings for postevent dementia were similar: prior functional impairment (40% versus 13%; P<0.0001), age >80 years (28% versus 10%; P<0.0001), dysphasia (39% versus 15%; P<0.0001), and comorbidity (20% versus 15%; P=0.04). CONCLUSIONS: Exclusion of patients unavailable for assessment, and other widely used selection criteria, results in underestimation of the measured rate of dementia associated with transient ischemic attack and stroke.

Validation of the Montreal cognitive assessment versus mini-mental state examination against hypertension and hypertensive arteriopathy after transient ischemic attack or minor stroke.

BACKGROUND AND PURPOSE: Lack of reduced cognitive impairment with blood pressure (BP) lowering in trials may reflect use of the Mini-Mental State Examination (MMSE), which is insensitive to mild cognitive impairment after cerebrovascular events compared with the Montreal Cognitive Assessment. We determined relationships between impairment on MMSE versus Montreal Cognitive Assessment (MoCA) with the major physiological determinant of vascular cognitive impairment: hypertension and hypertensive arteriopathy. METHODS: Cognitive impairment in consecutive patients 6 months after transient ischemic attack or minor stroke was defined as significant, mild, or none (MMSE<23, 23-26, ≥27; MoCA<20, 20-24, ≥25) and related to 20 premorbid systolic BP readings, home BP measurement (3 measurements, 3×daily for 1 month), and hypertensive arteriopathy (creatinine, stroke versus transient ischemic attack, leukoaraiosis) by ordinal regression. RESULTS: Of 463 patients, 45% versus 28% had at least mild cognitive impairment on the MoCA versus MMSE (P<0.001). Hypertensive arteriopathy was more strongly associated with cognitive impairment on the MoCA than MMSE (creatinine: odds ratio=3.99; 95% confidence interval, 2.06-7.73 versus 2.16, 1.08-4.33; event: 1.53, 1.06-2.19 versus 1.23, 0.81-1.85; leukoaraiosis: 2.09, 1.42-3.06 versus 1.34, 0.87-2.07). Premorbid and home BP measurement systolic BP were more strongly associated with impairment on vascular subdomains of the MoCA than MMSE (odds ratio/10 mm Hg: visuospatial 1.29 versus 1.05; attention 1.18 versus 1.07; language 1.22 versus 0.91; naming 1.07 versus 0.86). CONCLUSIONS: The stronger relationship between impairment on the MoCA with hypertensive arteriopathy, independent of age, indicates a greater sensitivity for vascular-origin cognitive impairment. Use of MoCA should improve sensitivity for cognitive impairment and treatment effects in future studies.

Age-specific incidence, outcome, cost, and projected future burden of atrial fibrillation-related embolic vascular events: a population-based study.

BACKGROUND: Prevalence of atrial fibrillation (AF) is >10% at age ≥80 years, but the impact of population aging on rates of AF-related ischemic events is uncertain. METHODS AND RESULTS: We studied age-specific incidence, outcome, and cost of all AF-related incident strokes and systemic emboli from 2002 to 2012 in the Oxford Vascular Study (OXVASC). We determined time trends in incidence of AF-related stroke in comparison with a sister study in 1981 to 1986, extrapolated numbers to the UK population and projected future numbers. Of 3096 acute cerebral or peripheral vascular events in the 92 728 study population, 383 incident ischemic strokes and 71 systemic emboli were related to AF, of which 272 (59.9%) occurred at ≥80 years. Of 597 fatal or disabling incident ischemic strokes, 262 (43.9%) were AF-related. Numbers of AF-related ischemic strokes at age ≥80 years increased nearly 3-fold from 1981-1986 to 2002-2012 (extrapolated to the United Kingdom: 6621 to 18 176 per year), due partly to increased age-specific incidence (relative rate 1.52, 95% confidence interval 1.31-1.77, P=0.001), with potentially preventable AF-related events at age ≥80 years costing the United Kingdom £374 million per year. At current incidence rates, numbers of AF-related embolic events at age ≥80 years will treble again by 2050 (72 974/year), with 83.5% of all events occurring in this age group. CONCLUSIONS: Numbers of AF-related incident ischemic strokes at age ≥80 years have trebled over the last 25 years, despite the introduction of anticoagulants, and are projected to treble again by 2050, along with the numbers of systemic emboli. Improved prevention in older people with AF should be a major public health priority.

Population-based study of blood biomarkers in prediction of subacute recurrent stroke.

BACKGROUND AND PURPOSE: Risk of recurrent stroke is high in the first few weeks after transient ischemic attack or stroke and clinical risk prediction tools have only limited accuracy, particularly after the hyperacute phase. Previous studies of the predictive value of biomarkers have been small, been done in selected populations, and have not concentrated on the acute phase or on intensively treated populations. We aimed to determine the predictive value of a panel of blood biomarkers in intensively treated patients early after transient ischemic attack and stroke. METHODS: We studied 14 blood biomarkers related to inflammation, thrombosis, atherogenesis, and cardiac or neuronal cell damage in early transient ischemic attack or ischemic stroke in a population-based study (Oxford Vascular Study). Biomarker levels were related to 90-day risk of recurrent stroke as hazard ratio (95% confidence interval) per decile increase, adjusted for age and sex. RESULTS: Among 1292 eligible patients, there were 53 recurrent ischemic strokes within 90 days. There were moderate correlations (r=0.40-0.61; P<0.0001) between the inflammatory biomarkers and between the cell damage and thrombotic subsets. Associations with risk of early recurrent stroke were weak, with significant associations limited to interleukin-6 (adjusted hazard ratio, 1.12; 1.01-1.24; P=0.033) and C-reactive protein (adjusted hazard ratio, 1.15; 1.02-1.30; P=0.022) after adjusting for age, sex, hypertension, smoking, and diabetes mellitus although P-selectin seemed to predict stroke after transient ischemic attack (adjusted hazard ratio, 1.28; 1.00-1.63; P=0.046). CONCLUSIONS: In the largest study to date, we found limited predictive use for early recurrent stroke for a panel of inflammatory, thrombotic, and cell damage biomarkers.

Acute post-stroke blood pressure relative to premorbid levels in intracerebral haemorrhage versus major ischaemic stroke: a population-based study.

BACKGROUND: It is often assumed that blood pressure increases acutely after major stroke, resulting in so-called post-stroke hypertension. In view of evidence that the risks and benefits of blood pressure-lowering treatment in acute stroke might differ between patients with major ischaemic stroke and those with primary intracerebral haemorrhage, we compared acute-phase and premorbid blood pressure levels in these two disorders. METHODS: In a population-based study in Oxfordshire, UK, we recruited all patients presenting with stroke between April 1, 2002, and March 31, 2012. We compared all acute-phase post-event blood pressure readings with premorbid readings from 10-year primary care records in all patients with acute major ischaemic stroke (National Institutes of Health Stroke Scale >3) versus those with acute intracerebral haemorrhage. FINDINGS: Of 653 consecutive eligible patients, premorbid and acute-phase blood pressure readings were available for 636 (97%) individuals. Premorbid blood pressure (total readings 13,244) had been measured on a median of 17 separate occasions per patient (IQR 8-31). In patients with ischaemic stroke, the first acute-phase systolic blood pressure was much lower than after intracerebral haemorrhage (158·5 mm Hg [SD 30·1] vs 189·8 mm Hg [38·5], p<0·0001; for patients not on antihypertensive treatment 159·2 mm Hg [27·8] vs 193·4 mm Hg [37·4], p<0·0001), was little higher than premorbid levels (increase of 10·6 mm Hg vs 10-year mean premorbid level), and decreased only slightly during the first 24 h (mean decrease from <90 min to 24 h 13·6 mm Hg). By contrast with findings in ischaemic stroke, the mean first systolic blood pressure after intracerebral haemorrhage was substantially higher than premorbid levels (mean increase of 40·7 mm Hg, p<0·0001) and fell substantially in the first 24 h (mean decrease of 41·1 mm Hg; p=0·0007 for difference from decrease in ischaemic stroke). Mean systolic blood pressure also increased steeply in the days and weeks before intracerebral haemorrhage (regression p<0·0001) but not before ischaemic stroke. Consequently, the first acute-phase blood pressure reading after primary intracerebral haemorrhage was more likely than after ischaemic stroke to be the highest ever recorded (OR 3·4, 95% CI 2·3-5·2, p<0·0001). In patients with intracerebral haemorrhage seen within 90 min, the highest systolic blood pressure within 3 h of onset was 50 mm Hg higher, on average, than the maximum premorbid level whereas that after ischaemic stroke was 5·2 mm Hg lower (p<0·0001). INTERPRETATION: Our findings suggest that systolic blood pressure is substantially raised compared with usual premorbid levels after intracerebral haemorrhage, whereas acute-phase systolic blood pressure after major ischaemic stroke is much closer to the accustomed long-term premorbid level, providing a potential explanation for why the risks and benefits of lowering blood pressure acutely after stroke might be expected to differ. FUNDING: Wellcome Trust, Wolfson Foundation, UK Medical Research Council, Stroke Association, British Heart Foundation, National Institute for Health Research.