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Background Currently there are multiple variations of imaging-based patient selection mismatch methods in ischemic stroke. In the present study, we sought to compare the two most common mismatch methods and identify if there were different effects on the outcome of a randomized clinical trial depending on the mismatch method used. Aims Investigate the effect of clinical and imaging-based mismatch criteria on patient outcomes of a pooled cohort from randomized trials of intravenous tenecteplase versus alteplase. Methods Baseline clinical and imaging scores were used to categorize patients as meeting either the DAWN mismatch (baseline NIHSS ≥ 10, and age cut-offs for ischemic core volume) or DEFUSE 2 mismatch criteria (mismatch volume > 15 mL, mismatch ratio > 1.8 and ischemic core Results From 146 pooled patients, 71 received alteplase and 75 received tenecteplase. The overall pooled group did not show improved patient outcomes when treated with tenecteplase (mRS 0-1 OR 1.77, 95% CI 0.89–3.51, p = 0.102) compared with alteplase. A total of 39 (27%) patients met both clinical and imaging mismatch criteria, 25 (17%) patients met only imaging criteria, 36 (25%) met only clinical mismatch criteria and, finally, 46 (31%) did not meet either of imaging or mismatch criteria. Patients treated with tenecteplase had more favorable outcomes when they met either imaging mismatch (mRS 0–1, OR 2.33, 95% CI 1.13–5.94, p = 0.032) or clinical mismatch criteria (mRS 0–1, OR 2.15, 95% CI 1.142, 8.732, p = 0.027) but with differing proportions. Conclusion Target mismatch selection was more inclusive and exhibited in a larger treatment effect between tenecteplase and alteplase.

Background and Purpose: Perfusion imaging is used for patient selection in clinical practice and trials. Postprocessing and definitions of tissue viability are nevertheless not standardized. We compared the lesion volumes generated with two well-recognized perfusion tissue definitions in a single-center phase 2 thrombolysis study. Methods: We analyzed perfusion imaging data from the Alteplase-Tenecteplase Trial Evaluation for Stroke Thrombolysis (ATTEST) study using two popular tissue viability thresholds (ischemic core definition: (1) cerebral blood volume 2 seconds; penumbra definitions: (1) mean transit time > 145% of contralesional hemisphere or (2) relative delay time < 2 seconds). We compared volumes of core and penumbra, mismatch ratio, percentage, and volume of penumbra salvaged at 24 hours. Results: We included 73 (tenecteplase = 36, alteplase = 37) patients who had analyzable perfusion lesions at baseline. Significant differences were found in core volumes using the two thresholds (33 ± 37 mL vs. 26 ± 32 mL, P < .001), as was mismatch ratio (2.5 ± .9 vs. 4.2 ± 3.7, P < 0.001). The volume of penumbra salvaged at 24 hours (30 ± 19 mL vs. 35 ± 26 mL, P = .043) differed significantly, although the percentages of penumbra salvaged did not (P= .2). No difference was found between the two thrombolytic agents in the percentages of penumbra salvaged using either threshold. Conclusion: Two commonly used tissue definitions generated significantly different lesion volumes and mismatch ratios. Threshold selection may have significant impact on patient selection for trials or reperfusion therapies.

Background: Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy.Methods: RESTART was a prospective, randomised, open-label, blinded-endpoint, parallel-group trial at 122 hospitals in the UK that assessed whether starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. For this prespecified subgroup analysis, consultant neuroradiologists masked to treatment allocation reviewed brain CT or MRI scans performed before randomisation to confirm participant eligibility and rate features of the intracerebral haemorrhage and surrounding brain. We followed participants for primary (recurrent symptomatic intracerebral haemorrhage) and secondary (ischaemic stroke) outcomes for up to 5 years (reported elsewhere). For this report, we analysed eligible participants with intracerebral haemorrhage according to their treatment allocation in primary subgroup analyses of cerebral microbleeds on MRI and in exploratory subgroup analyses of other features on CT or MRI. The trial is registered with the ISRCTN registry, number ISRCTN71907627.Findings: Between May 22, 2013, and May 31, 2018, 537 participants were enrolled, of whom 525 (98%) had intracerebral haemorrhage: 507 (97%) were diagnosed on CT (252 assigned to start antiplatelet therapy and 255 assigned to avoid antiplatelet therapy, of whom one withdrew and was not analysed) and 254 (48%) underwent the required brain MRI protocol (122 in the start antiplatelet therapy group and 132 in the avoid antiplatelet therapy group). There were no clinically or statistically significant hazards of antiplatelet therapy on recurrent intracerebral haemorrhage in primary subgroup analyses of cerebral microbleed presence (2 or more) versus absence (0 or 1) (adjusted hazard ratio [HR] 0·30 [95% CI 0·08–1·13] vs 0·77 [0·13–4·61]; pinteraction=0·41), cerebral microbleed number 0–1 versus 2–4 versus 5 or more (HR 0·77 [0·13–4·62] vs 0·32 [0·03–3·66] vs 0·33 [0·07–1·60]; pinteraction=0·75), or cerebral microbleed strictly lobar versus other location (HR 0·52 [0·004–6·79] vs 0·37 [0·09–1·28]; pinteraction=0·85). There was no evidence of heterogeneity in the effects of antiplatelet therapy in any exploratory subgroup analyses (all pinteraction>0·05).Interpretation: Our findings exclude all but a very modest harmful effect of antiplatelet therapy on recurrent intracerebral haemorrhage in the presence of cerebral microbleeds. Further randomised trials are needed to replicate these findings and investigate them with greater precision.Funding: British Heart Foundation.

Background and Purpose— Both intracerebral hemorrhage (ICH) and brain edema have been attributed to reperfusion after intravenous thrombolysis. We explored the interaction of recanalization and core size for imaging outcomes (ICH and vasogenic brain edema). Methods— In patients with anterior circulation occlusion given intravenous thrombolysis 2 s and relative cerebral blood flow 2 s). CT and CT angiography at 24 hours were reviewed for ICH (European Cooperative Acute Stroke Study [ECASS]-2 definition), early vasogenic edema (third International Stroke Trial [IST-3] criteria), and recanalization (thrombolysis in myocardial infarction 2–3). Independent effects of recanalization, core volume and potential interactions on edema, ICH and day 90 outcomes were estimated by logistic regression. Results— In 123 patients, there was a trend for recanalization to be associated with H1/2 ICH (odds ratio [OR], 2.3 [0.97–5.5]; P =0.06) but not with PH1/2 ICH (OR, 1.7 [0.33–8.8]; P =0.5), any edema, or significant brain edema (OR, 1.45 [0.4–4.9]; P =0.55). Ischemic core (>50 mL) was associated with any ICH (OR, 4.0 [1.6–9.5]; P =0.003), edema (OR, 5.4 [2–14]; P P P =0.8), after controlling for recanalization. There was no significant interaction of recanalization and large core for any adverse outcomes. Conclusions— Large ischemic core was associated with poorer outcomes and both early vasogenic brain edema and ICH, but recanalization on 24-hour CT angiography was associated with clinically favorable outcome. There was no significant interaction of recanalization and large core volume for any outcomes. The association of hemorrhage or brain edema with post-thrombolysis reperfusion is unclear.

Background and Purpose— We compared the fibrinolytic activity of tenecteplase and alteplase in patients with acute ischemic stroke, and explored the association between hypofibrinogenaemia and intracerebral hemorrhage. Methods— Venous blood samples from a subgroup of participants in the Alteplase–Tenecteplase Trial Evaluation for Stroke Thrombolysis (ATTEST) study were obtained at pretreatment, 3 to 12 hours, and 24±3 hours post-intravenous thrombolysis for analyses of plasminogen, plasminogen activator inhibitor-1, d -dimer, factor V, fibrinogen, and fibrin(ogen) degradation products, in addition to routine coagulation assays. Related sample Wilcoxon signed-rank tests were used to test the within-group changes, and independent Mann–Whitney tests for between-group differences. Results— Thirty patients were included (alteplase=14 and tenecteplase=16) with similar baseline demographics. Compared with baseline, alteplase caused significant hypofibrinogenaemia ( P =0.002), prolonged prothrombin time ( P =0.011), hypoplasminogenaemia ( P =0.001), and lower factor V ( P =0.002) at 3 to 12 hours after administration with persistent hypofibrinogenaemia at 24 hours ( P =0.011), whereas only minor hypoplasminogenaemia ( P =0.029) was seen in the tenecteplase group. Tenecteplase consumed less plasminogen ( P P =0.002) compared with alteplase. Conclusions— In patients with acute ischemic stroke, alteplase 0.9 mg/kg caused significant disruption of the fibrinolytic system, whereas tenecteplase 0.25 mg/kg did not, consistent with the trend toward lower intracerebral hemorrhage incidence with tenecteplase in the ATTEST study. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01472926.

Summary Background In most countries, alteplase given within 4·5 h of onset is the only approved medical treatment for acute ischaemic stroke. The newer thrombolytic drug tenecteplase has been investigated in one randomised trial up to 3 h after stroke and in another trial up to 6 h after stroke in patients selected by advanced neuroimaging. In the Alteplase-Tenecteplase Trial Evaluation for Stroke Thrombolysis (ATTEST), we aimed to assess the efficacy and safety of tenecteplase versus alteplase within 4·5 h of stroke onset in a population not selected on the basis of advanced neuroimaging, and to use imaging biomarkers to inform the design of a definitive phase 3 clinical trial. Methods In this single-centre, phase 2, prospective, randomised, open-label, blinded end-point evaluation study, adults with supratentorial ischaemic stroke eligible for intravenous thrombolysis within 4·5 h of onset were recruited from The Institute of Neurological Sciences, Glasgow, Scotland. Patients were randomly assigned (1:1) to receive tenecteplase 0·25 mg/kg (maximum 25 mg) or alteplase 0·9 mg/kg (maximum 90 mg). Treatment allocation used a mixed randomisation and minimisation algorithm including age and National Institutes of Health Stroke Scale score, generated by an independent statistician. Patients were not informed of treatment allocation; treating clinicians were aware of allocation but those assessing the primary outcome were not. Imaging comprised baseline CT, CT perfusion, and CT angiography; and CT plus CT angiography at 24–48 h. The primary endpoint was percentage of penumbra salvaged (CT perfusion-defined penumbra volume at baseline minus CT infarct volume at 24–48 h). Analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT01472926. Findings Between Jan 1, 2012, and Sept 7, 2013, 355 patients were screened, of whom 157 were eligible for intravenous thrombolysis, and 104 patients were enrolled. 52 were assigned to the alteplase group and 52 to tenecteplase. Of 71 patients (35 assigned tenecteplase and 36 assigned alteplase) contributing to the primary endpoint, no significant differences were noted for percentage of penumbral salvaged (68% [SD 28] for the tenecteplase group vs 68% [23] for the alteplase group; mean difference 1·3% [95% CI −9·6 to 12·1]; p=0·81). Neither incidence of symptomatic intracerebral haemorrhage (by SITS-MOST definition, 1/52 [2%] tenecteplase vs 2/51 [4%] alteplase, p=0·55; by ECASS II definition, 3/52 [6%] vs 4/51 [8%], p=0·59) nor total intracerebral haemorrhage events (8/52 [15%] vs 14/51 [29%], p=0·091) differed significantly. The incidence of serious adverse events did not differ between groups (32 in the tenecteplase group, three considered probably or definitely related to drug treatment; 16 in the alteplase group, five were considered drug-related). Interpretation Neurological and radiological outcomes did not differ between the tenecteplase and alteplase groups. Evaluation of tenecteplase in larger trials of patients with acute stroke seems warranted. Funding The Stroke Association.

Perfusion imaging is used for patient selection in clinical practice and trials. Postprocessing and definitions of tissue viability are nevertheless not standardized. We compared the lesion volumes generated with two well-recognized perfusion tissue definitions in a single-center phase 2 thrombolysis study.We analyzed perfusion imaging data from the Alteplase-Tenecteplase Trial Evaluation for Stroke Thrombolysis (ATTEST) study using two popular tissue viability thresholds (ischemic core definition: (1) cerebral blood volume2.0 mL/100 gWe included 73 (tenecteplase = 36, alteplase = 37) patients who had analyzable perfusion lesions at baseline. Significant differences were found in core volumes using the two thresholds (33 ± 37 mL vs. 26 ± 32 mL, P.001), as was mismatch ratio (2.5 ± .9 vs. 4.2 ± 3.7, P0.001). The volume of penumbra salvaged at 24 hours (30 ± 19 mL vs. 35 ± 26 mL, P = .043) differed significantly, although the percentages of penumbra salvaged did not (P = .2). No difference was found between the two thrombolytic agents in the percentages of penumbra salvaged using either threshold.Two commonly used tissue definitions generated significantly different lesion volumes and mismatch ratios. Threshold selection may have significant impact on patient selection for trials or reperfusion therapies.

Objective:To test whether patients with complete vessel occlusion show greater recanalization at 24 hours and have improved clinical outcomes at 24 hours and 90 days when treated with tenecteplase compared to alteplase.Methods:Pooled clinical and imaging data from 2 phase 2 randomized trials comparing tenecteplase with alteplase allowed CT angiography (CTA) scans to be assessed centrally for occlusion status at baseline and at 24 hours post thrombolysis using the modified thrombolysis in cerebral infarction (TICI) scale. Twenty-four-hour poststroke NIH Stroke Scale (NIHSS) and 90-day modified Rankin Scale (mRS) scores were also compared between treatment groups using linear regression to generate odds ratios (ORs).Results:From 146 pooled patients, 69 had a TICI 0/1 occlusion overall at baseline. Tenecteplase-treated patients with a complete vessel occlusion had greater complete recanalization rates at 24 hours (71% for tenecteplase vs 43% for alteplase, p < 0.001). Patients with a TICI 0/1 occlusion who were treated with tenecteplase also showed greater early clinical improvement (median NIHSS change with tenecteplase was 9, interquartile range [IQR] 6, alteplase 1, IQR 1, p = 0.001) and higher rates of favorable 90-day outcomes (mRS 0–1 of tenecteplase compared with alteplase, OR 4.82, 95% confidence interval 1.02–7.84, p = 0.05).Conclusions:Tenecteplase may offer greater recanalization efficacy compared to alteplase, possibly exaggerated in patients with complete vessel occlusions on baseline CTA.

Introduction Recent studies showed improved patient outcomes with endovascular treatment of acute stroke compared to medical care, including IV rtPA, alone. Seven trials have reported results, each using different clinical and imaging criteria for patient selection. We compared eligibility for different trial protocols to estimate the number of patients eligible for treatment. Patients and methods Patient data were extracted from a single centre database that combined patients recruited to three clinical studies, each of which obtained both CTA and CTP within 6 h of stroke onset. The published inclusion and exclusion criteria of seven intervention trials (MR CLEAN, EXTEND–IA, ESCAPE, SWIFT-PRIME, REVASCAT, THERAPY and THRACE) were applied to determine the proportion that would be eligible for each of these studies. Results A total of 263 patients was included. Eligibility for IAT in individual trials ranged from 53% to 3% of patients; 17% were eligible for four trials and under 10% for two trials. Only three patients (1%) were eligible for all studies. The most common cause of exclusion was absence of large artery occlusion (LAO) on CTA. When applying simplified criteria requiring an ASPECT score > 6, 16% were eligible for IAT, but potentially 40% of these patients were excluded by perfusion criteria and more than half by common NIHSS thresholds. Conclusion Around 15% of patients presenting within 6 h of stroke onset were potentially eligible for IAT, but clinical trial eligibility criteria have much more limited overlap than is commonly assumed and only 1% of patients fulfilled criteria for all recent trials.

Background: We pooled 2 clinical trials of tenecteplase compared with alteplase for the treatment of acute ischemic stroke, 1 that demonstrated superiority of tenecteplase and the other that showed no difference between the treatments in patient clinical outcomes. We tested the hypotheses that reperfusion therapy with tenecteplase would be superior to alteplase in improving functional outcomes in the group of patients with target mismatch as identified with advanced imaging. Methods: We investigated whether tenecteplase-treated patients had a different 24-hour reduction in the National Institutes of Health Stroke Scale and a favorable odds ratio of a modified Rankin scale score of 0 to 1 versus 2 to 6 compared with alteplase-treated patients using linear regression to generate odds ratios. Imaging outcomes included rates of vessel recanalization and infarct growth at 24 hours and occurrence of large parenchymal hematoma. Baseline computed tomography perfusion was analyzed to assess whether patients met the target mismatch criteria (absolute mismatch volume >15 mL, mismatch ratio >1.8, baseline ischemic core Results: Of 146 pooled patients, 71 received alteplase and 75 received tenecteplase. Tenecteplase-treated patients had greater early clinical improvement (median National Institutes of Health Stroke Scale score change: tenecteplase, 7; alteplase, 2; P =0.018) and less parenchymal hematoma (2 of 75 versus 10 of 71; P =0.02). The pooled group did not show improved patient outcomes when treated with tenecteplase (modified Rankin scale score 0–1: odds ratio, 1.77; 95% confidence interval, 0.89–3.51; P =0.102) compared with alteplase therapy. However, in patients with target mismatch (33 tenecteplase, 35 alteplase), treatment with tenecteplase was associated with greater early clinical improvement (median National Institutes of Health Stroke Scale score change: tenecteplase, 6; alteplase, 1; P P =0.032) than those treated with alteplase. Conclusions: Tenecteplase may offer an improved efficacy and safety profile compared with alteplase, benefits possibly exaggerated in patients with baseline computed tomography perfusion–defined target mismatch. Clinical Trial Registration: URL: http://www.clinicaltrials.gov . Unique identifier: NCT01472926. URL: https://www.anzctr.org.au . Unique identifier: ACTRN12608000466347.

Background The steep, time-dependent loss of benefit from reperfusion in clinical trials is consistent with loss of penumbra over the early hours of ischemia, as observed in animal models. Human imaging studies, however, show persistent penumbra for up to 48 h. We investigated core and penumbra volumes and collateral status in relation to time after stroke onset within the first 6 h. Methods Using data from three multimodal computer tomography-based studies in acute ischemic stroke patients 15 ml, mismatch ratio > 1.8). Patients were grouped by onset to imaging time (Results Analysis included 144 subjects. Across time epochs, neither proportions of penumbra (59%, 64%, 75% at 4. 5 h, respectively, p = 0.4) nor poor collaterals (15/56 (27%), 14/47 (30%), 4/15 (27%) at 4.5 h, p = 0.9) differed significantly. Penumbra proportion was not clearly related to time to imaging ( R2 = 0.003; p = 0.5) but a trend for divergent effects by collateral status was seen (slight increase in penumbra over time with good collaterals versus reduced with poor, interaction = 0.08). The proportion of patients with target mismatch did not vary by time (56%, 74%, and 67% at 4.5 h, p = 0.09). Conclusions In a cross-sectional sample imaged within 6 h, neither the proportions of penumbral tissue nor “target mismatch” varied by time from onset. A trend for reducing penumbra proportion only among those with poor collaterals may have pathophysiological and therapeutic importance.

Background and Purpose Malignant middle cerebral artery infarction(MMI) affects 5–10% of acute ischaemic stroke patients. Mortality of ∼80% if treated conservatively leaves decompressive surgery the choice treatment, halving mortality if undertaken early. We aimed to determine early clinical and CT based imaging factors that predict MMI. Methods We undertook a single centre retrospective study using an acute ischaemic stroke database that included CT head, CT angiography(CTA) and CT perfusion(CTP) scans 50% of MCA territory and space-occupying oedema on 24 h CT. Univariate and multivariate binary logistic regression identified predictive factors. Results Of 210 patients, 22 developed MMI. These had higher baseline NIHSS score, lower ASPECTS, larger ischaemic and infarct volumes, more large vessel occlusion and poor collateral circulation (all p= 75 ml on admission CTP, correctly classified 91.5% of patients. Conclusions CT imaging within 6 h of stroke onset can predict MMI. Multimodal CT allows early identification of those at risk of MMI.