Global Stroke Corner

01 Jun 2019

Carlsson M, Wilsgaard T, Johnsen SH, Johnsen LH, Løchen ML, Njølstad I, et al. The impact of risk factor trends on intracerebral hemorrhage incidence over the last two decades—The Tromsø Study. International Journal of Stroke. 2019;14(1):61-8.

Studies on the relationship between temporal trends in risk factors and incidence rates of intracerebral hemorrhage are scarce. Aims: To analyze temporal trends in risk factors and incidence rates of intracerebral hemorrhage using individual data from a population-based study. The authors included 28,167 participants of the Tromsø Study enrolled between 1994 and 2008. First-ever intracerebral hemorrhages were registered through 31 December 2013. Hazard ratios (HRs) for intracerebral hemorrhage were analyzed by Cox proportional hazards models, risk factor levels over time by generalized estimating equations, and incidence rate ratios (IRR) by Poisson regression. They registered 219 intracerebral hemorrhages. Age, male sex, systolic blood pressure (BP), diastolic BP, and hypertension were associated with intracerebral hemorrhage. Hypertension was more strongly associated with non-lobar intracerebral hemorrhage (HR 5.08, 95% CI 2.86–9.01) than lobar intracerebral hemorrhage (HR 1.91, 95% CI 1.12–3.25). In women, incidence decreased significantly (IRR 0.46, 95% CI 0.23–0.90), driven by a decrease in non-lobar intracerebral hemorrhage. Incidence rates in men remained stable (IRR 1.27, 95% CI 0.69–2.31). BP levels were lower and decreased more steeply in women than in men. The majority with hypertension were untreated, and a high proportion of those treated did not reach treatment goals. The authors concluded that there was a significant decrease in intracerebral hemorrhage incidence in women, but not in men. A steeper BP decrease in women may have contributed to the diverging trends. The high proportion of untreated and sub-optimally treated hypertension calls for improved strategies for prevention of intracerebral hemorrhage.

Wu S, Wu B, Liu M, Chen Z, Wang W, Anderson CS, et al. Stroke in China: advances and challenges in epidemiology, prevention, and management. The Lancet Neurology. 2019;18(4):394-405.

With over 2 million new cases annually, stroke is associated with the highest disability-adjusted life-years lost of any disease in China. The burden is expected to increase further as a result of population ageing, an ongoing high prevalence of risk factors (eg, hypertension), and inadequate management. Despite improved access to overall health services, the availability of specialist stroke care is variable across the country, and especially uneven in rural areas. In-hospital outcomes have improved because of a greater availability of reperfusion therapies and supportive care, but adherence to secondary prevention strategies and long-term care are inadequate. Thrombolysis and stroke units are accepted as standards of care across the world, including in China, but bleeding-risk concerns and organisational challenges hamper widespread adoption of this care in China. Despite little supporting evidence, Chinese herbal products and neuroprotective drugs are widely used, and the increased availability of neuroimaging techniques also results in overdiagnosis and overtreatment of so-called silent stroke. Future efforts should focus on providing more balanced availability of specialised stroke services across the country, enhancing evidence-based practice, and encouraging greater translational research to improve outcome of patients with stroke.

Pendlebury ST, Rothwell PM, Oxford Vascular S. Incidence and prevalence of dementia associated with transient ischaemic attack and stroke: analysis of the population-based Oxford Vascular Study. The Lancet Neurology. 2019;18(3):248-58.

Risk of dementia after stroke is a major concern for patients and carers. Reliable data for risk of dementia, particularly after transient ischaemic attack or minor stroke, are scarce. We studied the risks of, and risk factors for, dementia before and after transient ischaemic attack and stroke. Methods: The Oxford Vascular Study is a prospective incidence study of all vascular events in a population of 92 728 people residing in Oxfordshire, UK. Patients with transient ischaemic attack or stroke occurring between April 1, 2002, and March 31, 2012, were ascertained with multiple methods, including assessment in a dedicated daily emergency clinic and daily review of all hospital admissions. Pre-event and post-event (incident) dementia were diagnosed at initial assessment and during 5-years' follow-up on the basis of cognitive testing supplemented by data obtained from hand searches of all hospital and primary care records. We assessed the association between post-event dementia and stroke severity (as measured with the US National Institutes of Health Stroke Scale [NIHSS] score), location (ie, dysphasia), previous events, markers of susceptibility or reserve (age, low education, pre-morbid dependency, leucoaraiosis), baseline cognition, and vascular risk factors with Cox regression models adjusted for age, sex, and education. We compared incidence and prevalence of dementia in our population with published UK population age-matched and sex-matched rates. Findings: Among 2305 patients (mean age 74·4 years [SD 13·0]), 688 (30%) had transient ischaemic attacks and 1617 (70%) had strokes. Pre-event dementia was diagnosed in 225 patients; prevalence was highest in severe stroke (ie, NIHSS >10) and lowest in transient ischaemic attack. Of 2080 patients without pre-event dementia, 1982 (95%) were followed up to the end of study or death. Post-event dementia occurred in 432 of 2080 patients during 5 years of follow-up. The incidence of post-event dementia at 1 year was 34·4% (95% CI 29·7–41·5) in patients with severe stroke (NIHSS score >10), 8·2% (6·2–10·2) in those with minor stroke (NIHSS score <3), and 5·2% (3·4–7·0) in those with transient ischaemic attack. Compared with the UK age-matched and sex-matched population, the 1-year standardised morbidity ratio for the incidence of dementia was 47·3 (95% CI 35·9–61·2), 5·8 (4·4–7·5), and 3·5 (2·5–4·8), respectively. Consequently, prevalence of dementia in 1-year survivors was brought forward by approximately 25 years in those who had severe strokes, 4 years in those who had minor strokes, and 2 years in those who had transient ischaemic attacks. 5-year risk of dementia was associated with age, event severity, previous stroke, dysphasia, baseline cognition, low education, pre-morbid dependency, leucoaraiosis, and diabetes (p<0·0001 for all comparisons, except for previous stroke [p=0·006]). Interpretation: The incidence of dementia in patients who have had a transient ischaemic attack or stroke varies substantially depending on clinical characteristics including lesion burden and susceptibility factors. Incidence of dementia is nearly 50 times higher in the year after a major stroke compared with that in the general population, but excess risk is substantially lower after transient ischaemic attack and minor stroke.

Johnson CO, Nguyen M, Roth GA, Nichols E, Alam T, Abate D, et al. Global, regional, and national burden of stroke, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. The Lancet Neurology. 2019;18(5):439-58.

Stroke is a leading cause of mortality and disability worldwide and the economic costs of treatment and post-stroke care are substantial. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic, comparable method of quantifying health loss by disease, age, sex, year, and location to provide information to health systems and policy makers on more than 300 causes of disease and injury, including stroke. The results presented here are the estimates of burden due to overall stroke and ischaemic and haemorrhagic stroke from GBD 2016. Methods: We report estimates and corresponding uncertainty intervals (UIs), from 1990 to 2016, for incidence, prevalence, deaths, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs). DALYs were generated by summing YLLs and YLDs. Cause-specific mortality was estimated using an ensemble modelling process with vital registration and verbal autopsy data as inputs. Non-fatal estimates were generated using Bayesian meta-regression incorporating data from registries, scientific literature, administrative records, and surveys. The Socio-demographic Index (SDI), a summary indicator generated using educational attainment, lagged distributed income, and total fertility rate, was used to group countries into quintiles. Findings: In 2016, there were 5·5 million (95% UI 5·3 to 5·7) deaths and 116·4 million (111·4 to 121·4) DALYs due to stroke. The global age-standardised mortality rate decreased by 36·2% (−39·3 to −33·6) from 1990 to 2016, with decreases in all SDI quintiles. Over the same period, the global age-standardised DALY rate declined by 34·2% (−37·2 to −31·5), also with decreases in all SDI quintiles. There were 13·7 million (12·7 to 14·7) new stroke cases in 2016. Global age-standardised incidence declined by 8·1% (−10·7 to −5·5) from 1990 to 2016 and decreased in all SDI quintiles except the middle SDI group. There were 80·1 million (74·1 to 86·3) prevalent cases of stroke globally in 2016; 41·1 million (38·0 to 44·3) in women and 39·0 million (36·1 to 42·1) in men. Interpretation: Although age-standardised mortality rates have decreased sharply from 1990 to 2016, the decrease in age-standardised incidence has been less steep, indicating that the burden of stroke is likely to remain high. Planned updates to future GBD iterations include generating separate estimates for subarachnoid haemorrhage and intracerebral haemorrhage, generating estimates of transient ischaemic attack, and including atrial fibrillation as a risk factor.

Dichgans M, Pulit SL, Rosand J. Stroke genetics: discovery, biology, and clinical applications. The Lancet Neurology. 2019;18(6):587-99.

Stroke, a leading cause of long-term disability and death worldwide, has a heritable component. Recent gene discovery efforts have expanded the number of known single-gene disorders associated with stroke and have linked common variants at approximately 35 genetic loci to stroke risk. These discoveries have highlighted novel mechanisms and pathways implicated in stroke related to large artery atherosclerosis, cardioembolism, and small vessel disease, and defined shared genetic influences with related vascular traits. Genetics has also successfully established causal relationships with risk factors and holds promise for prioritising targets for exploration in clinical trials. Genome-wide polygenic scores enable the identification of high-risk individuals before the emergence of vascular risk factors. Challenges ahead include a better understanding of rare variants and ancestral differences for integration of genetics into precision medicine, integration with other omics data, uncovering the genetic factors that govern stroke recurrence and stroke outcome, and the conversion of genetic discoveries to novel therapies.

Anderson C., et al. Intensive blood pressure reduction with intravenous thrombolysis therapy for acute ischaemic stroke (ENCHANTED): an international, randomised, open-label, blinded-endpoint, phase 3 trial. The Lancet Volume 393, Issue 10174, 2–8 March 2019, Pages 877-888

Systolic blood pressure of more than 185 mm Hg is a contraindication to thrombolytic treatment with intravenous alteplase in patients with acute ischaemic stroke, but the target systolic blood pressure for optimal outcome is uncertain. We assessed intensive blood pressure lowering compared with guideline-recommended blood pressure lowering in patients treated with alteplase for acute ischaemic stroke. The authors did an international, partial-factorial, open-label, blinded-endpoint trial of thrombolysis-eligible patients (age ≥18 years) with acute ischaemic stroke and systolic blood pressure 150 mm Hg or more, who were screened at 110 sites in 15 countries. Eligible patients were randomly assigned (1:1, by means of a central, web-based program) within 6 h of stroke onset to receive intensive (target systolic blood pressure 130–140 mm Hg within 1 h) or guideline (target systolic blood pressure <180 mm Hg) blood pressure lowering treatment over 72 h. The primary outcome was functional status at 90 days measured by shift in modified Rankin scale scores, analysed with unadjusted ordinal logistic regression. The key safety outcome was any intracranial haemorrhage. Primary and safety outcome assessmentswere done in a blinded manner. Analyses were done on intention-to-treat basis. This trial is registered with ClinicalTrials.gov, number NCT01422616. Between March 3, 2012, and April 30, 2018, 2227 patients were randomly allocated to treatment groups. After exclusion of 31 patients because of missing consent or mistaken or duplicate randomisation, 2196 alteplase-eligible patients with acute ischaemic stroke were included: 1081 in the intensive group and 1115 in the guideline group, with 1466 (67·4%) administered a standard dose among the 2175 actually given intravenous alteplase. Median time from stroke onset to randomisation was 3·3 h (IQR 2·6–4·1). Mean systolic blood pressure over 24 h was 144·3 mm Hg (SD 10·2) in the intensive group and 149·8 mm Hg (12·0) in the guideline group (p<0·0001). Primary outcome data were available for 1072 patients in the intensive group and 1108 in the guideline group. Functional status (mRS score distribution) at 90 days did not differ between groups (unadjusted odds ratio [OR] 1·01, 95% CI 0·87–1·17, p=0·8702). Fewer patients in the intensive group (160 [14·8%] of 1081) than in the guideline group (209 [18·7%] of 1115) had any intracranial haemorrhage (OR 0·75, 0·60–0·94, p=0·0137). The number of patients with any serious adverse event did not differ significantly between the intensive group (210 [19·4%] of 1081) and the guideline group (245 [22·0%] of 1115; OR 0·86, 0·70–1·05, p=0·1412). There was no evidence of an interaction of intensive blood pressure lowering with dose (low vs standard) of alteplase with regard to the primary outcome. Although intensive blood pressure lowering is safe, the observed reduction in intracranial haemorrhage did not lead to improved clinical outcome compared with guideline treatment. These results might not support a major shift towards this treatment being applied in those receiving alteplase for mild-to-moderate acute ischaemic stroke. Further research is required to define the underlying mechanisms of benefit and harm resulting from early intensive blood pressure lowering in this patient group.

Markus HS, Levi C, King A, Madigan J, Norris J. Antiplatelet Therapy vs Anticoagulation Therapy in Cervical Artery Dissection: The Cervical Artery Dissection in Stroke Study (CADISS) Randomized Clinical Trial Final Results. JAMA Neurology. 2019 (in press)

Extracranial carotid and vertebral artery dissection is an important cause of stroke, particularly in younger individuals. In some but not all observational studies, it has been associated with a high risk of recurrent stroke. Both antiplatelet agents (APs) and anticoagulants (ACs) are used to reduce stroke risk, but whether 1 treatment strategy is more effective is unknown. Objective: To determine whether AP or AC therapy is more effective in preventing stroke in cervical dissection and the risk of recurrent stroke in a randomized clinical trial setting. A secondary outcome was to determine the effect on arterial imaging outcomes. Design, Setting and Participants: Randomized, prospective, open-label international multicenter parallel design study with central blinded review of both clinical and imaging end points. Recruitment was conducted in 39 stroke and neurology secondary care centers in the United Kingdom and 7 centers in Australia between February 24, 2006, and June 17, 2013. One-year follow-up and analysis was conducted in 2018. Two hundred fifty participants with extracranial carotid and vertebral dissection with symptom onset within the last 7 days were recruited. Follow-up data at 1 year were available for all participants. Interventions: Randomization to AP or AC (heparin followed by warfarin) for 3 months, after which the choice of AP and AC agents was decided by the local clinician. Main Outcomes and Measures: The primary end point was ipsilateral stroke and death. A planned per protocol (PP) analysis was performed in patients meeting the inclusion criteria following central review of imaging to confirm the diagnosis of dissection. A secondary end point was angiographic recanalization in those with imaging confirmed dissection. Results: Two hundred fifty patients were randomized (118 carotid and 132 vertebral), 126 to AP and 124 to AC. Mean (SD) age was 49 (12) years. Mean (SD) time to randomization was 3.65 (1.91) days. The recurrent stroke rate at 1 year was 6 of 250 (2.4%) on ITT analysis and 5 of 197 (2.5%) on PP analysis. There were no significant differences between treatment groups for any outcome. Of the 181 patients with confirmed dissection and complete imaging at baseline and 3 months, there was no difference in the presence of residual narrowing or occlusion between those receiving AP (n = 56 of 92) vs those receiving AC (n = 53 of 89) (P =.97). Conclusions and Relevance: During 12 months of follow-up, the number of recurrent strokes was low. There was no difference between treatment groups in outcome events or the rate of recanalization.

Campbell BCV, Ma H, Ringleb PA, et al. EXTEND, ECASS-4, and EPITHET Investigators.

Extending thrombolysis to 4·5-9 h and wake-up stroke using perfusion imaging: a systematic review and meta-analysis of individual patient data.

Lancet. 2019 May 21. doi: 10.1016/S0140-6736(19)31053-0. [Epub ahead of print] PMID: 31128925

Thrombolysis for acute ischaemic stroke is currently recommended 0-4·5 h after stroke onset.

This meta-analysis of individual patient data from three randomised controlled trials of alteplase versus placebo in a total of 414 adults with ischaemic stroke treated more than 4·5 h after onset, or with wake-up stroke, who had evidence of salvageable brain tissue (mismatch between smaller core of infarction and larger penumbra) on perfusion-diffusion MRI or CT perfusion imaging, found that 76 (36%) of 211 patients in the alteplase group and 58 (29%) of 199 patients in the placebo group had achieved excellent functional outcome at 3 months (adjusted odds ratio [OR] 1·86, 95% CI 1·15-2·99, p=0·011). Symptomatic intracerebral haemorrhage was more common in the alteplase group than the placebo group (ten [5%] of 213 patients vs one [<1%] of 201 patients in the placebo group; adjusted OR 9·7, 95% CI 1·23-76·55, p=0·031). 29 (14%) of 213 patients in the alteplase group and 18 (9%) of 201 patients in the placebo group died (adjusted OR 1·55, 0·81-2·96, p=0·66).

This study extends the time window for thrombolysis for acute ischaemic stroke up to 9 hours after stroke onset or wake-up stroke if there is salvageable brain tissue on CT or MRI imaging

Diener HC, Sacco RL, Easton JD, et al RE-SPECT ESUS Steering Committee and Investigators.

Dabigatran for Prevention of Stroke after Embolic Stroke of Undetermined Source.

N Engl J Med. 2019 May 16;380(20):1906-1917.

In this randomized, double-blind trial of 5390 patients with recent (< 3 months) embolic stroke of undetermined source, dabigatran at a dose of 150 mg or 110 mg twice daily was not superior to aspirin at a dose of 100 mg once daily in preventing recurrent stroke over a median follow-up of 19 months (6.6% in the dabigatran group [4.1% per year] vs 7.7% in the aspirin group [4.8% per year]; hazard ratio, 0.85; 95% CI, 0.69 to 1.03; P = 0.10).

The incidence of major bleeding was similar in both groups (1.7% per year dabigatran group vs 1.4% per year aspirin group; HR, 1.19; 95% CI, 0.85 to 1.66), but there were more clinically relevant non-major bleeding events in the dabigatran group (1.6% per year vs 0.9% per year.

Toyoda K, Uchiyama S, Yamaguchi T,for the CSPS.com Trial Investigators.

Dual antiplatelet therapy using cilostazol for secondary prevention in patients with high-risk ischaemic stroke in Japan: a multicentre, open-label, randomised controlled trial.

Lancet Neurol. 2019 Jun;18(6):539-548.

In this trial, 1884 patients with recent (8-180 days previous) non-cardioembolic ischaemic stroke were randomly assigned to receive monotherapy with either oral aspirin (81 or 100 mg, once per day) or clopidogrel (50 or 75 mg, once per day) alone, or a combination of cilostazol (100 mg, twice per day) with aspirin or clopidogrel. After a median follow-up of 1.4 years, a first recurrence of symptomatic ischaemic stroke occurred in 29 (3%) of 932 patients (annualised rate 2·2%) on dual therapy including cilostazol and 64 (7%) of 947 patients (annualised rate 4·5%) on monotherapy (hazard ratio [HR] 0·49, 95% CI 0·31-0·76, p=0·0010). There was no difference between groups in severe or life-threatening bleeding (annualised rate 0·6% on dual therapy and 0·9% on monotherapy; HR 0·66, 95% CI 0·27-1·60, p=0·35).

These data indicate that in Japanese patients with high risk non-cardioembolic ischaemic stroke, the combination of cilostazol with aspirin or clopidogrel reduces the incidence of recurrent ischaemic stroke without increasing risk of severe or life-threatening bleeding compared with treatment with aspirin or clopidogrel alone.

RESTART Collaboration

Effects of antiplatelet therapy after stroke due to intracerebral haemorrhage (RESTART): a randomised, open-label trial.

Lancet. 2019 May 21. doi: 10.1016/S0140-6736(19)30840-2. [Epub ahead of print] PMID: 31128924

The REstart or STop Antithrombotics Randomised Trial (RESTART) found that among 537 adults with an intracerebral haemorrhage who were taking antithrombotic (antiplatelet or anticoagulant) therapy for the prevention of occlusive vascular disease when they developed the ICH, discontinued antithrombotic therapy, and survived for 24 h, randomisation to re-start (vs avoid) antiplatelet therapy was associated with less recurrent intracerebral haemorrhage (4%) compared with 9% of participants allocated to avoid antiplatelet therapy (adjusted hazard ratio 0·51 [95% CI 0·25-1·03]; p=0·060).

These results exclude all but a very modest increase in the risk of recurrent intracerebral haemorrhage with antiplatelet therapy for patients on antithrombotic therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage. The risk of recurrent intracerebral haemorrhage is probably too small to exceed the established benefits of antiplatelet therapy for secondary prevention.

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