2,944 research outputs found
Safety of intravenous thrombolysis for acute ischemic stroke in patients receiving antiplatelet therapy at stroke onset
No full text<p><b>Background and Purpose:</b> Antiplatelets (APs) may increase the risk of symptomatic intracerebral hemorrhage (ICH) following intravenous thrombolysis after ischemic stroke.</p>
<p><b>Methods:</b> We assessed the safety of thrombolysis under APs in 11 865 patients compliant with the European license criteria and recorded between 2002 and 2007 in the Safe Implementation of Treatments in Stroke (SITS) International Stroke Thrombolysis Register (SITS-ISTR). Outcome measures of univariable and multivariable analyses included symptomatic ICH (SICH) per SITS Monitoring Study (SITS-MOST [deterioration in National Institutes of Health Stroke Scale >= 4 plus ICH type 2 within 24 hours]), per European Cooperative Acute Stroke Study II (ECASS II [deterioration in National Institutes of Health Stroke Scale >= 4 plus any ICH]), functional outcome at 3 months and mortality.</p>
<p><b>Results:</b> A total of 3782 (31.9%) patients had received 1 or 2 AP drugs at baseline: 3016 (25.4%) acetylsalicylic acid (ASA), 243 (2.0%) clopidogrel, 175 (1.5%) ASA and dipyridamole, 151 (1.3%) ASA and clopidogrel, and 197 (1.7%) others. Patients receiving APs were 5 years older and had more risk factors than AP nave patients. Incidences of SICH per SITS-MOST (ECASS II respectively) were as follows: 1.1% (4.1%) AP naive, 2.5% (6.2%) any AP, 2.5% (5.9%) ASA, 1.7% (4.2%) clopidogrel, 2.3% (5.9%) ASA and dipyridamole, and 4.1% (13.4%) ASA and clopidogrel. In multivariable analyses, the combination of ASA and clopidogrel was associated with increased risk for SICH per ECASS II (odds ratio, 2.11; 95% CI, 1.29 to 3.45; P = 0.003). However, we found no significant increase in the risk for mortality or poor functional outcome, irrespective of the AP subgroup or SICH definition.</p>
<p><b>Conclusion:</b> The absolute excess of SICH of 1.4% (2.1%) in the pooled AP group is small compared with the benefit of thrombolysis seen in randomized trials. Although caution is warranted in patients receiving the combination of ASA and clopidogrel, AP treatment should not be considered a contraindication to thrombolysis.</p>
The Desmoteplase In Acute Ischemic Stroke Trial (DIAS): a phase II MRI-based 9-hour window acute stroke thrombolysis trial with intravenous desmoteplase
No full text<p><b>Background and Purpose:</b> Most acute ischemic stroke patients arrive after the 3-hour time window for recombinant tissue plasminogen activator (rtPA) administration. The Desmoteplase In Acute Ischemic Stroke trial (DIAS) was a dose-finding randomized trial designed to evaluate the safety and efficacy of intravenous desmoteplase, a highly fibrin-specific and nonneurotoxic thrombolytic agent, administered within 3 to 9 hours of ischemic stroke onset in patients with perfusion/diffusion mismatch on MRI.</p>
<p><b>Methods:</b> DIAS was a placebo-controlled, double-blind, randomized, dose-finding phase II trial. Patients with National Institute of Health Stroke Scale (NIHSS) scores of 4 to 20 and MRI evidence of perfusion/diffusion mismatch were eligible. Of 104 patients, the first 47 (referred to as Part 1) were randomized to fixed doses of desmoteplase (25 mg, 37.5 mg, or 50 mg) or placebo. Because of an excessive rate of symptomatic intracranial hemorrhage (sICH), lower weight-adjusted doses escalating through 62.5 μg⁄kg, 90 μg⁄kg, and 125 μg⁄kg were subsequently investigated in 57 patients (referred to as Part 2). The safety endpoint was the rate of sICH. Efficacy endpoints were the rate of reperfusion on MRI after 4 to 8 hours and clinical outcome as assessed by NIHSS, modified Rankin scale, and Barthel Index at 90 days.</p>
<p><b>Results:</b> Part 1 was terminated prematurely because of high rates of sICH with desmoteplase (26.7%). In Part 2, the sICH rate was 2.2%. No sICH occurred with placebo in either part. Reperfusion rates up to 71.4% (P=0.0012) were observed with desmoteplase (125 μg/kg) compared with 19.2% with placebo. Favorable 90-day clinical outcome was found in 22.2% of placebo-treated patients and between 13.3% (62.5 μg⁄kg; P=0.757) and 60.0% (125 μg⁄kg; P=0.0090) of desmoteplase-treated patients. Early reperfusion correlated favorably with clinical outcome (P=0.0028). Favorable outcome occurred in 52.5% of patients experiencing reperfusion versus 24.6% of patients without reperfusion.</p>
<p><b>Conclusions:</b> Intravenous desmoteplase administered 3 to 9 hours after acute ischemic stroke in patients selected with perfusion/diffusion mismatch is associated with a higher rate of reperfusion and better clinical outcome compared with placebo. The sICH rate with desmoteplase was low, using doses up to 125 μg⁄kg.</p>
Thrombolysis is associated with consistent functional improvement across baseline stroke severity: a comparison of outcomes in patients from the Virtual International Stroke Trials Archive (VISTA)
No full text<p><b>Background and Purpose:</b> Baseline stroke severity predicts outcomes among thrombolysed patients. The baseline National Institutes of Health Stroke Scale (NIHSS) thresholds are sometimes used to select patients for thrombolysis, clinical trial enrollment, or both. Using data lodged with Virtual International Stroke Trials Archive, we compared adjusted outcomes between thrombolysed and nonthrombolysed patients enrolled in neuroprotection trials (1998-2007) to assess the influence of various levels of baseline NIHSS.</p>
<p><b>Method:</b> We assessed the association of treatment with outcome, measured across the modified Rankin scale score distribution, in patients categorized by baseline NIHSS in increments of 4. We used an age and baseline NIHSS adjusted Cochran-Mantel-Haenszel test followed by proportional odds logistic regression analysis. We report the Cochran-Mantel-Haenszel P values and estimated odds ratios (OR) for improved modified Rankin scale score distribution with treatment for patients within each baseline NIHSS category.</p>
<p><b>Results:</b> Data were available for 5817 patients (1585 thrombolysed and 4232 nonthrombolysed). Baseline severity was greater among thrombolysed than nonthrombolysed (median baseline NIHSS, 14 vs 13; P<0.05). An association of treatment with outcome was seen independently and was of similar magnitude within each of the baseline NIHSS categories 5 to 8 (P=0.04; OR, 1.25; 95% confidence interval [CI], 1.0-1.6; N=278/934 thrombolysed/nonthrombolysed), 9 to 12 (P=0.01; OR, 1.3; 95% CI, 1.1-1.6; N=404/942), 13 to 16 (P<0.05; OR, 1.6; 95% CI, 1.3-2.1; N=342/814), 17 to 20 (P<0.05; OR, 1.7; 95% CI, 1.3-2.1; N=311/736), and 21 to 24 (P<0.05; OR, 1.6; 95% CI, 1.1-2.1; N=178/466). No association was observed within baseline NIHSS categories 1 to 4 (P=0.8; OR, 1.1; 95% CI, 0.3-4.4; N=8/161) or >= 25 (P=0.08; OR, 1.1; 95% CI, 0.7-1.9; N=64/179).</p>
<p><b>Conclusions:</b> In this nonrandomized comparison, outcomes after thrombolysis were significantly better than in untreated comparators across baseline NIHSS 5 to 24. The significant association was lost only at extremes of baseline NIHSS when sample sizes were small and confidence limits were wide.</p>
Contemporary outcome measures in acute stroke research: choice of primary outcome measure
No full textBACKGROUND AND PURPOSE:
The diversity of available outcome measures for acute stroke trials is challenging and implies that the scales may be imperfect. To assist researchers planning trials and to aid interpretation, this article reviews and makes recommendations on the available choices of scales. The aim is to identify an approach that will be universally accepted and that should be included in most acute trials, without seeking to restrict options for special circumstances.
METHODS:
The article considers outcome measures that have been widely used or are currently advised. It examines desirable properties for outcome measures such as validity, relevance, responsiveness, statistical properties, availability of training, cultural and language issues, resistance to comorbidity, as well as potential weaknesses. Tracking and agreement among outcomes are covered.
RESULTS:
Typical ranges of scores for the common scales are described, along with their statistical properties, which in turn influence optimal analytic techniques. The timing of recovery on scores and usual practice in trial design are considered.
CONCLUSIONS:
The preferred outcome measure for acute trials is the modified Rankin Scale, assessed at 3 months after stroke onset or later. The interview should be conducted by a certified rater and should involve both the patient and any relevant caregiver. Incremental benefits at any level of the modified Rankin Scale may be acceptable. The modified Rankin Scale is imperfect but should be retained in its present form for comparability with existing treatment comparisons. No second measure should be required, but correlations with supporting scales may be used to confirm consistency in direction of effects on other measures
Additional outcomes and subgroup analyses of NXY-059 for acute ischemic stroke in the SAINT I trial
No full text<p><b>Background and Purpose:</b> NXY-059 is a free radical-trapping neuroprotectant demonstrated to reduce disability from ischemic stroke. We conducted analyses on additional end points and sensitivity analyses to confirm our findings.</p>
<p><b>Methods:</b> We randomized 1722 patients with acute ischemic stroke to a 72-hour infusion of placebo or intravenous NXY-059 within 6 hours of stroke onset. The primary outcome was disability at 90 days, as measured by the modified Rankin Scale (mRS), a 6-point scale ranging from 0 (no residual symptoms) to 5 (bed-bound, requiring constant care). Additional and exploratory analyses included mRS at 7 and 30 days; subgroup interactions with final mRS; assessments of activities of daily living by Barthel index; and National Institutes of Health Stroke Scale (NIHSS) neurological scores at 7 and 90 days.</p>
<p><b>Results:</b> NXY-059 significantly improved the distribution of the mRS disability score compared with placebo at 7, 30, and 90 days (Cochran-Mantel-Haenszel test P=0.002, 0.004, 0.038, respectively; 90-day common odds ratio 1.20; 95% CI, 1.01 to 1.42). The benefit was not attributable to any specific baseline characteristic, stratification variable or subgroup interaction. Neurological scores were improved at 7 days (odds ratio [OR], 1.46; 95% CI, 1.13, 1.89; P=0.003) and the Barthel index was improved at 7 and 30 days (OR, 1.55; 95% CI, 1.22, 1.98; P<0.0001; OR, 1.27; 95% CI, 1.01, 1.59; P=0.02).</p>
<p><b>Conclusions:</b> NXY-059 within 6 hours of acute ischemic stroke significantly reduced disability. Benefit on neurological scores and activities of daily living was detectable early but not significant at 90 days; however, our trial was underpowered to measure effects on the neurological examination. The benefit on disability is not confounded by interactions and is supported by other outcome measures.</p>
Early outcomes of thrombolysis for acute ischaemic stroke in a South African tertiary care centre
No full textIncludes abstract.Includes bibliographical references.Stroke is an important cause of death and disability in sub-Saharan Africa. Recombinant tissue plasminogen activator (tPA) thrombolysis is effective in treating acute ischaemic stroke, but may not be a viable option in developing countries. This prospective observational study was designed to assess the short-termoutcomes and safety of tPA for the treatment of stroke at Groote Schuur Hospital.Data was collected from January 2000 to February 2012, and included patients witha clinical diagnosis of acute stroke with onset of stroke symptoms within 4.5 hours ofreceiving thrombolysis. Exclusion criteria were based on the National Institute ofNeurological Disorders and Stroke (NINDS) rt-PA trial protocol (upper age limit was 75 years). Primary outcomes were the proportion of patients achieving significant early neurological recovery defined as an improvement of 4 or more points on the National Institutes of Health stroke scale (NIHSS) score and functional independence defined as a modified Rankin score of 2 or less at discharge. The primary safety measures were the rates of symptomatic intracranial haemorrhage (SICH) and death. From January 2000 to February 2011 42 patients were thrombolysed, with a mean time to tPA infusion of 160 minutes (standard deviation (SD) 50; range 60 - 270). By discharge the median NIHSS score fell from 14 (interquartile range (IQR) 10.5 - 17) to 7.5 (IQR 1 - 15); 28 (66.7%) achieved significant neurological improvement, and 17 (40.5%) were functionally independent. Two patients (4.8%) suffered SICH and there were 3 (7.1%) deaths. Thrombolysis in routine clinical practice in a South African setting has similar safety and early efficacy outcomes to controlled trials and open-label studies in developing and developed countries
Magnesium for treatment of acute lacunar stroke syndromes: further analysis of the IMAGES trial
No full text<p><b>Background and Purpose:</b> A prespecified interaction analysis of the neutral Intravenous Magnesium Efficacy in Stroke (IMAGES) trial revealed significant benefit from magnesium (Mg) in patients with noncortical stroke. Post hoc analysis indicated that this effect was seen in lacunar clinical syndromes (LACS), interaction P=0.005. We have now examined whether this interaction could be explained by confounding baseline factors.</p>
<p><b>Methods:</b> LACS was defined on the basis of neurological signs and did not include imaging. We investigated the interaction between baseline variables and Mg treatment on global outcome. We used logistic-regression models to test whether the Mg-LACS interaction remained significant after adjusting for stratification variables, sex, a novel stroke severity score, and baseline variables that had an interaction with treatment (P<0.1).</p>
<p><b>Results:</b> The Mg (n=383) and placebo (n=382) groups of LACS patients were well matched on baseline factors. In addition to LACS, we found an interaction between beneficial Mg treatment effect and younger age (P=0.003), higher baseline diastolic blood pressure (P=0.02), higher mean blood pressure (P=0.02), and absence of ischemic heart disease (P=0.07). Even so, the adjusted Mg-LACS interaction remained significant (odds ratio [OR] 0.57; 95% CI, 0.39 to 0.83; P=0.003). In the LACS subgroup, Mg improved Barthel Index <95 (OR 0.73; 95% CI, 0.55 to 0.98), modified Rankin Scale >1 (OR 0.67; 95% CI, 0.50 to 0.91), and global outcome (OR 0.70; 95% CI, 0.53 to 0.92) but not Barthel Index <60 or mortality.</p>
<p><b>Conclusions:</b> The positive treatment effect of Mg in LACS cannot be ascribed to general issues of severity, time to treatment, blood pressure, or other baseline factors; equally, this finding may be due to chance. A large trial of Mg treatment in LACS appears justified.</p>
Initial experience of a digital training resource for modified Rankin scale assessment in clinical trials
No full text<p><b>Background and Purpose:</b> The modified Rankin Scale (mRS) is the preferred measure of disability in cerebrovascular clinical trials, but its value is restricted by interobserver variability. Poor reliability reduces the statistical power of clinical trials and leads to underestimation of effect size. Strategies to improve mRS grading are required. Video training has previously improved application of the National Institutes of Health Stroke Scale in clinical research. We developed an mRS training resource in an attempt to minimize interobserver variability.</p>
<p><b>Methods:</b> We produced a complete training resource comprising an instructional DVD with accompanying written materials and assessment recordings of patient interviews. Formal assessment of training involved grading of real-life cases. Results of initial training and recertification were collected centrally and scored.</p>
<p><b>Results:</b> Data from 1564 assessments are presented. The majority of assessors were participating in 2 large prospective clinical stroke trials. Assessors represented a mixed group of disciplines and nationalities. After training, most trainees (90%) achieved certification in mRS assessment. The majority (85%) of investigators who did not reach an acceptable score on initial testing achieved certification after further exposure to the package.</p>
<p><b>Conclusions:</b> Mass training in mRS assessment for clinical trials is possible. We outline the development of a video-based training package, including technical issues, patient selection procedures, and methods of scoring and assessment. Certification results suggest that use of the resource can improve mRS grading. Acceptability of the training has been demonstrated by its successful use in 2 international acute stroke trials, SAINT 1 and CHANT.</p>
Statistical analysis of the primary outcome in acute stroke trials
No full textCommon outcome scales in acute stroke trials are ordered categorical or pseudocontinuous in structure but most have been analyzed as binary measures. The use of fixed dichotomous analysis of ordered categorical outcomes after stroke (such as the modified Rankin Scale) is rarely the most statistically efficient approach and usually requires a larger sample size to demonstrate efficacy than other approaches. Preferred statistical approaches include sliding dichotomous, ordinal, or continuous analyses. Because there is no best approach that will work for all acute stroke trials, it is vital that studies are designed with a full understanding of the type of patients to be enrolled (in particular their case mix, which will be critically dependent on their age and severity), the potential mechanism by which the intervention works (ie, will it tend to move all patients somewhat, or some patients a lot, and is a common hazard present), a realistic assessment of the likely effect size, and therefore the necessary sample size, and an understanding of what the intervention will cost if implemented in clinical practice. If these approaches are followed, then the risk of missing useful treatment effects for acute stroke will diminish
- …
