Effect of IV alteplase on the ischemic brain lesion at 24-48 hours after ischemic stroke

OBJECTIVE: To determine whether alteplase alters the development of ischemic lesions on brain imaging after stroke. METHODS: The Third International Stroke Trial (IST-3) was a randomized controlled trial of IV alteplase for ischemic stroke. We assessed CT or brain MRI at baseline (pretreatment) and 24 to 48 hours posttreatment for acute lesion visibility, extent, and swelling, masked to all other data. We analyzed associations between treatment allocation, change in brain tissue appearances between baseline and follow-up imaging, and 6-month functional outcome in IST-3. We performed a meta-analysis of randomized trials of alteplase vs control with pre- and postrandomization imaging. RESULTS: Of 3,035 patients recruited in IST-3, 2,916 had baseline and follow-up brain imaging. Progression in either lesion extent or swelling independently predicted poorer 6-month outcome (adjusted odds ratio [OR] = 0.92, 95% confidence interval [CI] 0.88-0.96, p < 0.001; OR = 0.73, 95% CI 0.66-0.79, p < 0.001, respectively). Patients allocated alteplase were less likely than controls to develop increased lesion visibility at follow-up (OR = 0.77, 95% CI 0.67-0.89, p < 0.001), but there was no evidence that alteplase reduced progression of lesion extent or swelling. In meta-analysis of 6 trials including IST-3 (n = 4,757), allocation to alteplase was associated with a reduction in ischemic lesion extent on follow-up imaging (OR = 0.85, 95% CI 0.76-0.95, p = 0.004). CONCLUSION: Alteplase was associated with reduced short-term progression in lesion visibility. In meta-analysis, alteplase reduced lesion extent. These findings may indicate that alteplase improves functional outcome by reducing tissue damage. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that IV alteplase impedes the progression of ischemic brain lesions on imaging after stroke

Hyperdense artery sign, symptomatic infarct swelling and effect of alteplase in acute ischaemic stroke

Alteplase improves functional outcomes of patients with acute ischaemic stroke, but its effects on symptomatic infarct swelling, an adverse complication of stroke and the influence of CT hyperdense artery sign (HAS) are unclear. This substudy of the Third International Stroke Trial aimed to investigate the association between HAS and symptomatic infarct swelling and effect of intravenous alteplase on this association. We included stroke patients whose prerandomisation scan was non-contrast CT. Raters, masked to clinical information, assessed baseline (prerandomisation) and follow-up (24-48 hours postrandomisation) CT scans for HAS, defined as an intracranial artery appearing denser than contralateral arteries. Symptomatic infarct swelling was defined as clinically significant neurological deterioration ≤7 days after stroke with radiological evidence of midline shift, effacement of basal cisterns or uncal herniation. Among 2961 patients, HAS presence at baseline was associated with higher risk of symptomatic infarct swelling (OR 2.21; 95% CI 1.42 to 3.44). Alteplase increased the risk of swelling (OR 1.69; 95% CI 1.11 to 2.57), with no difference between patients with and those without baseline HAS (p=0.49). In patients with baseline HAS, alteplase reduced the proportion with HAS at follow-up (OR 0.67; 95% CI 0.50 to 0.91), where HAS disappearance was associated with reduced risk of swelling (OR 0.25, 95% CI 0.14 to 0.47). Although alteplase was associated with increased risk of symptomatic infarct swelling in patients with or without baseline HAS, it was also associated with accelerated clearance of HAS, which in return reduced swelling, providing further mechanistic insights to underpin the benefits of alteplase

Blood pressure variability and leukoaraiosis in acute ischemic stroke

Higher blood pressure, blood pressure variability, and leukoaraiosis are risk factors for early adverse events and poor functional outcome after ischemic stroke, but prior studies differed on whether leukoaraiosis was associated with blood pressure variability, including in ischemic stroke. In the Third International Stroke Trial, blood pressure was measured in the acute phase of ischemic stroke immediately prior to randomization, and at 0.5, 1, and 24 h after randomization. Masked neuroradiologists rated index infarct, leukoaraiosis, and atrophy on CT using validated methods. We characterized blood pressure variation by coefficient of variance and three other standard methods. We measured associations between blood pressure, blood pressure variability, and leukoaraiosis using generalized estimating equations, adjusting for age, and a number of covariates related to treatment and stroke type/severity. Among 3017 patients, mean (±SD) systolic and diastolic blood pressure decreased from 155(±24)/82(±15) mmHg pre-randomization to 146(±23)/78(±14) mmHg 24 h later ( P &lt; 0.005). Mean within-subject coefficient of variance was 0.09 ± 0.05 for systolic and 0.11 ± 0.06 for diastolic blood pressure. Patients with most leukoaraiosis were older and had higher blood pressure than those with least ( P &lt; 0.0001). Although statistically significant in simple pairwise comparisons, no measures of blood pressure variability were associated with leukoaraiosis when adjusting for confounding variables ( P &gt; 0.05), e.g. age. Our results suggest that blood pressure variability is not a potential mechanism to explain the association between leukoaraiosis and poor outcome after acute stroke

Effect of alteplase on the CT hyperdense artery sign and functional outcome after ischemic stroke

© 2015 American Academy of Neurology. STUDY FUNDING The startup phase of IST-3 was supported by a grant from the Stroke Association, UK (TSA 04/99). The expansion phase was funded by the Health Foundation UK (2268/1282). The scan reading development was funded by Chest, Heart Stroke Scotland (R100/7). The main phase of the trial is funded by UK Medical Research Council (MRC) (grant numbers G0400069 and EME 09-800-15) and managed by NIHR on behalf of the MRC-NIHR partnership; the Research Council of Norway; Arbetsmarknadens Partners Forsakringsbolag (AFA) Insurances Sweden; the Swedish Heart Lung Fund; The Foundation of Marianne and Marcus Wallenberg, Stockholm County Council; Karolinska Institute Joint ALF-project grants Sweden; the Polish Ministry of Science and Education (grant number 2PO5B10928); the Australian Heart Foundation; Australian National Health and Medical Research Council (NHMRC); the Swiss National Research Foundation; the Swiss Heart Foundation; the Foundation for Health and Cardio-/Neurovascular Research, Basel, Switzerland; the Assessorato alla Sanita, Regione dell'Umbria, Italy; and, Danube University, Krems, Austria. Boehringer-Ingelheim GmbH donated drug and placebo for the 300 patients in the double-blind phase, but thereafter had no role in the trial. The UK Stroke Research Network (SRN study ID 2135) adopted the trial on 1/5/2006, supported the initiation of new UK sites, and in some centers, and, after that date, data collection was undertaken by staff funded by the network or working for associated NHS organizations. IST-3 acknowledges the support of the NIHR Stroke Research Network, NHS Research Scotland (NRS), through the Scottish Stroke Research Network, and the National Institute for Social Care and Health Research Clinical Research Centre (NISCHR CRC). The central imaging work was undertaken at the Brain Imaging Research Centre (www.sbirc.ed.ac.uk), a member of the Scottish Imaging Network: A Platform for Scientific Excellence (SINAPSE) collaboration (www.sinapse.ac.uk), at the Division of Clinical Neurosciences, University of Edinburgh. SINAPSE is funded by the Scottish Funding Council (SFC) and the Chief Scientist Office of the Scottish Executive (CSO). Additional support was received from Chest Heart and Stroke Scotland, DesAcc, University of Edinburgh, Danderyd Hospital R&D Department, Karolinska Institutet, Oslo University Hospital, and the Dalhousie University Internal Medicine Research Fund.Peer reviewedPublisher PD

Association between brain imaging signs, early and late outcomes, and response to intravenous alteplase after acute ischaemic stroke in the third international stroke trial (IST-3): Secondary analysis of a randomised controlled trial

Background: Brain scans are essential to exclude haemorrhage in patients with suspected acute ischaemic stroke before treatment with alteplase. However, patients with early ischaemic signs could be at increased risk of haemorrhage after alteplase treatment, and little information is available about whether pre-existing structural signs, which are common in older patients, affect response to alteplase. We aimed to investigate the association between imaging signs on brain CT and outcomes after alteplase. Methods: IST-3 was a multicentre, randomised controlled trial of intravenous alteplase (0·9 mg/kg) versus control within 6 h of acute ischaemic stroke. The primary outcome was independence at 6 months (defined as an Oxford Handicap Scale [OHS] score of 0-2). 3035 patients were enrolled to IST-3 and underwent prerandomisation brain CT. Experts who were unaware of the random allocation assessed scans for early signs of ischaemia (tissue hypoattenuation, infarct extent, swelling, and hyperattenuated artery) and pre-existing signs (old infarct, leukoaraiosis, and atrophy). In this prespecified analysis, we assessed interactions between these imaging signs, symptomatic intracranial haemorrhage (a secondary outcome in IST-3) and independence at 6 months, and alteplase, adjusting for age, National Institutes of Health Stroke Scale (NIHSS) score, and time to randomisation. This trial is registered at ISRCTN.com, number ISRCTN25765518. Findings: 3017 patients were assessed in this analysis, of whom 1507 were allocated alteplase and 1510 were assigned control. A reduction in independence was predicted by tissue hypoattenuation (odds ratio 0·66, 95% CI 0·55-0·81), large lesion (0·51, 0·38-0·68), swelling (0·59, 0·46-0·75), hyperattenuated artery (0·59, 0·47-0·75), atrophy (0·74, 0·59-0·94), and leukoaraiosis (0·72, 0·59-0·87). Symptomatic intracranial haemorrhage was predicted by old infarct (odds ratio 1·72, 95% CI 1·18-2·51), tissue hypoattenuation (1·54, 1·04-2·27), and hyperattenuated artery (1·54, 1·03-2·29). Some combinations of signs increased the absolute risk of symptomatic intracranial haemorrhage (eg, both old infarct and hyperattenuated artery, excess with alteplase 13·8%, 95% CI 6·9-20·7; both signs absent, excess 3·2%, 1·4-5·1). However, no imaging findings-individually or combined-modified the effect of alteplase on independence or symptomatic intracranial haemorrhage. Interpretation: Some early ischaemic and pre-existing signs were associated with reduced independence at 6 months and increased symptomatic intracranial haemorrhage. Although no interaction was noted between brain imaging signs and effects of alteplase on these outcomes, some combinations of signs increased some absolute risks. Pre-existing signs should be considered, in addition to early ischaemic signs, during the assessment of patients with acute ischaemic stroke. Funding: UK Medical Research Council, Health Foundation UK, Stroke Association UK, Chest Heart Stroke Scotland, Scottish Funding Council SINAPSE Collaboration, and multiple governmental and philanthropic national funders