Kennedy R. Lees

Background and Purpose—: Clinical trials in stroke typically measure outcome after 90 days. Earlier outcome assessment would reduce costs and may increase power. We aimed to compare the sensitivity of 4 end points (modified Rankin Scale [mRS] at 30 and 90 days, and National Institutes of Health Stroke Scale (NIHSS) at 7 and 90 days, analyzed as ordinal measures) to detect the established treatment effect of recombinant tissue-type plasminogen activator (rtPA). Methods—: Within the Virtual International Stroke Trials Archive, we compared rtPA–treated patients with untreated control subjects using a multiple resampling approach. From our total sample we drew 10 000 random samples of unique patients, constraining the sample sizes in treated and untreated groups to be equal. In each of these samples we tested for the treatment effect of rtPA by each of the 4 studied end points. The percentage of samples yielding significant results approximates the power of each end point at a given sample size. This process was repeated across a range of sample sizes, to determine the relationship between sample size and power for each of the 4 end points. Results—: For our 4 end points of mRS at 30 and 90 days, and NIHSS at 7 and 90 days the smallest sample sizes required to generate statistical power >80% were 620, 480, 370, and 420, respectively, making 7-day NIHSS the most sensitive end point. These results were supported by dichotomized analyses. Conclusions—: Seven-day NIHSS score appears a sensitive end point that should be validated in randomized trial datasets for use in exploratory stroke trials.

Background 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.

Background and Purpose— Thrombolysis for acute ischemic stroke in patients aged >80 years is not approved in some countries due to limited trial data in the very elderly. We compared outcomes between thrombolysed and nonthrombolysed (control) patients from neuroprotection trials to assess any influence of age on response. Method— Among patients with ischemic stroke of known age, pretreatment severity (baseline National Institutes of Health Scale Score), and 90-day outcome (modified Rankin Scale score; National Institutes of Health Scale score), we compared the distribution of modified Rankin score in thrombolysed patients with control subjects by Cochran-Mantel-Haenszel test and then logistic regression after adjustment for age and baseline National Institutes of Health Scale score. We examined patients ≤80 and ≥81 years separately and then each age decile. Results— Rankin data were available for 5817 patients, 1585 thrombolysed and 4232 control subjects; 20.5% were aged >80 years (mean±SD, 85.1±3.4 years). Baseline severity was higher among thrombolysed than control subjects (median National Institutes of Health Scale score 14 versus 13, P P P 30 years; outcomes assessed by National Institutes of Health Scale score gave supporting significant findings, and dichotomized modified Rankin Scale score outcomes were also consistent. Conclusions— Outcome after thrombolysis for acute ischemic stroke was significantly better than in control subjects. Despite the expected poorer outcomes among elderly compared with young patients that is independent of any treatment effect, the association between thrombolysis treatment and improved outcome is maintained in the very elderly. Age alone should not be a barrier to treatment.

Objective To assess effect of age on response to alteplase in acute ischaemic stroke. Design Adjusted controlled comparison of outcomes between non-randomised patients who did or did not undergo thrombolysis. Analysis used Cochran-Mantel-Haenszel test and proportional odds logistic regression analysis. Setting Collaboration between International Stroke Thrombolysis Registry (SITS-ISTR) and Virtual International Stroke Trials Archive (VISTA). Participants 23 334 patients from SITS-ISTR (December 2002 to November 2009) who underwent thrombolysis and 6166 from VISTA neuroprotection trials (1998-2007) who did not undergo thrombolysis (as controls). Of the 29 500 patients (3472 aged >80 (“elderly,” mean 84.6), data on 272 patients were missing for baseline National Institutes of Health stroke severity score, leaving 29 228 patients for analysis adjusted for age and baseline severity. Main outcome measures Functional outcomes at 90 days measured by score on modified Rankin scale. Results Median severity at baseline was the same for patients who underwent thrombolysis and controls (median baseline stroke scale score: 12 for each group, P=0.14; n=29 228). The distribution of scores on the modified Rankin scale was better among all thrombolysis patients than controls (odds ratio 1.6, 95% confidence interval 1.5 to 1.7; Cochran-Mantel-Haenszel Pv 2-6; 0-2 v 3-6; and 6 (death) v rest) were consistent with the results of the ordinal analysis. Conclusions Outcome in patients with acute ischaemic stroke is significantly better in those who undergo thrombolysis compared with those who do not. Increasing age is associated with poorer outcome but the association between thrombolysis treatment and improved outcome is maintained in very elderly people. Age alone should not be a barrier to treatment.

Background and Purpose— 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. Method— 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. Results— 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 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 P P 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). Conclusions— 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.

OBJECTIVE The use of alteplase in patients who have had a prior stroke and concomitant diabetes is not approved in Europe. To examine the influence of diabetes and prior stroke on outcomes, we compared data on thrombolysed patients with nonthrombolysed comparators. RESEARCH DESIGN AND METHODS We selected patients with ischemic stroke on whom we had data on age, pretreatment baseline National Institutes of Health Stroke Scale (b-NIHSS), and 90-day outcome measures (functional modified Rankin score [mRS]) and neurological measures [NIHSS]) in the Virtual International Stroke Trials Archive. We compared outcomes between thrombolysed patients and nonthrombolysed comparators in those with and without diabetes, those who have had a prior stroke, or both and report findings using the Cochran-Mantel-Haenszel (CMH) test and proportional odds logistic regression analyses. We report an age-adjusted and b-NIHSS–adjusted CMH P value and odds ratio (OR). RESULTS Rankin data were available for 5,817 patients: 1,585 thrombolysed patients and 4,232 nonthrombolysed comparators. A total 1,334 (24.1%) patients had diabetes, 1,898 (33.7%) patients have had a prior stroke, and 491 (8%) patients had both. Diabetes and nondiabetes had equal b-NIHSS (median 13; P = 0.3), but patients who have had a prior stroke had higher b-NIHSS than patients who have not had a prior stroke (median 13 vs. 12; P < 0.0001). Functional outcomes were better for thrombolysed patients versus nonthrombolysed comparators among both nondiabetic (P < 0.0001; OR 1.4 [95% CI 1.3–1.6]) and diabetic (P = 0.1; 1.3 [1.05–1.6 ]) subjects. Similarly, outcomes were better for thrombolysed patients versus nonthrombolysed comparators among who have not had a prior stroke (P < 0.0001; 1.4 [1.2–1.6 ]) and those who have (P = 0.02; 1.3 [1.04–1.6 ]). There was no interaction of diabetes and prior stroke with treatment (P = 0.8). Neurological outcomes were consistent with the mRS. CONCLUSIONS Outcomes from thrombolysis are better among patients with diabetes and/or those who have had a prior stroke than in control subjects. Withholding thrombolytic treatment from otherwise-eligible patients may not be justified.

Background and Purpose— Clinical benefit from thrombolysis is reduced as stroke onset to treatment time increases. The use of “mismatch” imaging to identify patients for delayed treatment has face validity and has been used in case series and clinical trials. We undertook a meta-analysis of relevant trials to examine whether present evidence supports delayed thrombolysis among patients selected according to mismatch criteria. Methods— We collated outcome data for patients who were enrolled after 3 hours of stroke onset in thrombolysis trials and had mismatch on pretreatment imaging. We selected the trials on the basis of a systematic search of the Web of Knowledge. We compared favorable outcome, reperfusion and/or recanalization, mortality, and symptomatic intracerebral hemorrhage between the thrombolyzed and nonthrombolyzed groups of patients and the probability of a favorable outcome among patients with successful reperfusion and clinical findings for 3 to 6 versus 6 to 9 hours from poststroke onset. Results are expressed as adjusted odds ratios (a-ORs) with 95% CIs. Heterogeneity was explored by test statistics for clinical heterogeneity, I ² (inconsistency), and L’Abbé plot. Results— We identified articles describing the DIAS, DIAS II, DEDAS, DEFUSE, and EPITHET trials, giving a total of 502 mismatch patients thrombolyzed beyond 3 hours. The combined a-ORs for favorable outcomes were greater for patients who had successful reperfusion (a-OR=5.2; 95% CI, 3 to 9; I ² =0%). Favorable clinical outcome was not significantly improved by thrombolysis (a-OR=1.3; 95% CI, 0.8 to 2.0; I ² =20.9%). Odds for reperfusion/recanalization were increased among patients who received thrombolytic therapy (a-OR=3.0; 95% CI, 1.6 to 5.8; I ² =25.7%). The combined data showed a significant increase in mortality after thrombolysis (a-OR=2.4; 95% CI, 1.2 to 4.9; I ² =0%), but this was not confirmed when we excluded data from desmoteplase doses that were abandoned in clinical development (a-OR=1.6; 95% CI, 0.7 to 3.7; I ² =0%). Symptomatic intracerebral hemorrhage was significantly increased after thrombolysis (a-OR=6.5; 95% CI, 1.2 to 35.4; I ² =0%) but not significant after exclusion of abandoned doses of desmoteplase (a-OR=5.4; 95% CI, 0.9 to 31.8; I ² =0%). Conclusions— Delayed thrombolysis amongst patients selected according to mismatch imaging is associated with increased reperfusion/recanalization. Recanalization/reperfusion is associated with improved outcomes. However, delayed thrombolysis in mismatch patients was not confirmed to improve clinical outcome, although a useful clinical benefit remains possible. Thrombolysis carries a significant risk of symptomatic intracerebral hemorrhage and possibly increased mortality. Criteria to diagnose mismatch are still evolving. Validation of the mismatch selection paradigm is required with a phase III trial. Pending these results, delayed treatment, even according to mismatch selection, cannot be recommended as part of routine care.