Anticoagulants for acute ischaemic stroke

Peer reviewedPublisher PD

Does intermittent pneumatic compression reduce the risk of post stroke deep vein thrombosis?:The CLOTS 3 trial: statistical analysis plan

BACKGROUND: Venous thromboembolism (VTE) is a common and important complication of stroke. The CLOTS 3 trial aims to determine whether, compared with best medical care, best medical care plus intermittent pneumatic compression (IPC) in immobile stroke patients reduces the risk of proximal deep vein thrombosis (DVT). METHODS/DESIGN: The CLOTS 3 trial is a multicenter, parallel group trial with centralized randomization (minimization) to ensure allocation concealment. The protocol has been published (Trials 2012, 13:26) and is available in full at: http://www.clotstrial.com. Between December 2008 and September 2012, 105 centers in the UK recruited 2,876 immobile stroke patients within the first 3 days of their hospital admission. Patients were allocated to best medical care or best medical care plus IPC. Ultrasonographers performed a compression Doppler ultrasound scan to detect DVT in each treatment group at 7 to 10 days and 25 to 30 days. The primary outcome cluster includes symptomatic or asymptomatic DVT in the popliteal or femoral veins detected on either scan. Patients will be followed up by postal or telephone questionnaire at 6 months from randomization to detect later symptomatic DVT and pulmonary embolism (PE), and to measure functional outcome (Oxford Handicap Scale) and quality of life (EQ-5D-3L). The ultrasonographers performing the scans are blinded to treatment allocation, whereas the patients and caregivers are not. The trial has more than 90% power to detect a 4% absolute difference (12% versus 8%) in risk of the primary outcome and includes a health economic analysis. Follow-up will be completed in April 2013 and the results reported in May 2013. In this update, we describe the statistical analysis plan. TRIAL REGISTRATION: ISRCTN: ISRCTN9352999

The Clots in Legs Or sTockings after Stroke (CLOTS) 3 trial : a randomised controlled trial to determine whether or not intermittent pneumatic compression reduces the risk of post-stroke deep vein thrombosis and to estimate its cost-effectiveness

Peer reviewedPublisher PD

Effects of alteplase for acute stroke according to criteria defining the European Union and United States marketing authorizations: individual-patient-data meta-analysis of randomized trials

Background: The recommended maximum age and time window for intravenous alteplase treatment of acute ischemic stroke differs between the Europe Union and United States. Aims: We compared the effects of alteplase in cohorts defined by the current Europe Union or United States marketing approval labels, and by hypothetical revisions of the labels that would remove the Europe Union upper age limit or extend the United States treatment time window to 4.5 h. Methods: We assessed outcomes in an individual-patient-data meta-analysis of eight randomized trials of intravenous alteplase (0.9 mg/kg) versus control for acute ischemic stroke. Outcomes included: excellent outcome (modified Rankin score 0–1) at 3–6 months, the distribution of modified Rankin score, symptomatic intracerebral hemorrhage, and 90-day mortality. Results: Alteplase increased the odds of modified Rankin score 0–1 among 2449/6136 (40%) patients who met the current European Union label and 3491 (57%) patients who met the age-revised label (odds ratio 1.42, 95% CI 1.21−1.68 and 1.43, 1.23−1.65, respectively), but not in those outside the age-revised label (1.06, 0.90−1.26). By 90 days, there was no increased mortality in the current and age-revised cohorts (hazard ratios 0.98, 95% CI 0.76−1.25 and 1.01, 0.86–1.19, respectively) but mortality remained higher outside the age-revised label (1.19, 0.99–1.42). Similarly, alteplase increased the odds of modified Rankin score 0-1 among 1174/6136 (19%) patients who met the current US approval and 3326 (54%) who met a 4.5-h revised approval (odds ratio 1.55, 1.19−2.01 and 1.37, 1.17−1.59, respectively), but not for those outside the 4.5-h revised approval (1.14, 0.97−1.34). By 90 days, no increased mortality remained for the current and 4.5-h revised label cohorts (hazard ratios 0.99, 0.77−1.26 and 1.02, 0.87–1.20, respectively) but mortality remained higher outside the 4.5-h revised approval (1.17, 0.98–1.41). Conclusions: An age-revised European Union label or 4.5-h-revised United States label would each increase the number of patients deriving net benefit from alteplase by 90 days after acute ischemic stroke, without excess mortality

Controversies in Thrombolysis

Purpose of review: to examine recent evidence on the effects of intravenous thrombolysis and identify the remaining uncertainties. Recent findings: We review the results of two large trials (the third International Stroke Trial (IST-3), and The Enhanced Control of Hypertension and Thrombolysis Stroke Study (ENCHANTED) and the publications from the individual patient data analyses of the trials of alteplase conducted by the Stroke Thrombolysis Trialists Collaboration. Summary: Despite about a 2% risk of fatal intracerebral haemorrhage, on average, adult patients of all ages treated with 0.9 mg/kg alteplase within 4.5 hours will have better long-term functional outcome. The use of a lower dose of alteplase (0.6mg/kg) is associated with a lower risk of haemorrhage but its effect on functional outcome has not been proven to be non-inferior to standard dose therapy. Some clinicians feel confident to treat selected patients who present beyond 4.5 hours or have unknown time of onset, but many also agree that the current trials and other research is needed to reliably define the optimum imaging methods and treatment eligibility criteri

Brain imaging, the legal process and neurofantasy; can it be cured (by applying the principles of evidence – based medicine)?

Advanced brain imaging techniques, originally designed for medical and basic science research purposes, are now being applied in a much wider range of settings for very diverse purposes. There is a concern that some of the exaggerated claims for the utility of these technologies in these new settings, combined with their inappropriate use (or uncritical interpretation) may lead to a variety of unintended and sometimes adverse consequences. We propose that the principles of critical appraisal, developed for assessing medical technologies (so called ‘evidence-based medicine’), might usefully be applied to reduce the risk of such unintended consequences. In this article, we discuss how these principles might be relevant to the application of neuroimaging techniques to various aspects of the law and the legal process

Arterial Obstruction on Computed Tomographic or Magnetic Resonance Angiography and Response to Intravenous Thrombolytics in Ischemic Stroke

BACKGROUND AND PURPOSE: Computed tomographic angiography and magnetic resonance angiography are used increasingly to assess arterial patency in patients with ischemic stroke. We determined which baseline angiography features predict response to intravenous thrombolytics in ischemic stroke using randomized controlled trial data. METHODS: We analyzed angiograms from the IST-3 (Third International Stroke Trial), an international, multicenter, prospective, randomized controlled trial of intravenous alteplase. Readers, masked to clinical, treatment, and outcome data, assessed prerandomization computed tomographic angiography and magnetic resonance angiography for presence, extent, location, and completeness of obstruction and collaterals. We compared angiography findings to 6-month functional outcome (Oxford Handicap Scale) and tested for interactions with alteplase, using ordinal regression in adjusted analyses. We also meta-analyzed all available angiography data from other randomized controlled trials of intravenous thrombolytics. RESULTS: In IST-3, 300 patients had prerandomization angiography (computed tomographic angiography=271 and magnetic resonance angiography=29). On multivariable analysis, more extensive angiographic obstruction and poor collaterals independently predicted poor outcome (P1 indicates benefit) in patients with (odds ratio, 2.07; 95% confidence interval, 1.18-3.64; P=0.011) versus without (odds ratio, 0.88; 95% confidence interval, 0.58-1.35; P=0.566) arterial obstruction (P for interaction 0.017). CONCLUSIONS: Intravenous thrombolytics provide benefit to stroke patients with computed tomographic angiography or magnetic resonance angiography evidence of arterial obstruction, but the sample was underpowered to demonstrate significant treatment benefit or harm among patients with apparently patent arteries. CLINICAL TRIAL REGISTRATION: URL: http://www.isrctn.com. Unique identifier: ISRCTN25765518