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BACKGROUND AND OBJECTIVES: Endovascular thrombectomy (EVT) is effective for patients with large vessel occlusion (LVO) stroke with smaller volumes of CT perfusion (CTP)-defined ischemic core. However, the benefit of EVT is unclear in those with a core volume >70 mL. We aimed to compare outcomes of EVT and non-EVT patients with an ischemic core volume ≥70 mL, hypothesizing that there would be a benefit from EVT for fair outcome (3-month modified Rankin scale [mRS] 0-3) after stroke. METHODS: A retrospective analysis of patients enrolled into a multicenter (Australia, China, and Canada) registry (2012-2020) who underwent CTP within 24 hours of stroke onset and had a baseline ischemic core volume ≥70 mL was performed. The primary outcome was the estimation of the association of EVT in patients with core volume ≥70 mL and within 70-100 and ≥100 mL subgroups with fair outcome. RESULTS: Of the 3,283 patients in the registry, 299 had CTP core volume ≥70 mL and 269 complete data (135 had core volume between 70 and 100 mL and 134 had core volume ≥100 mL). EVT was performed in 121 (45%) patients. EVT-treated patients were younger (median 69 vs 75 years; p = 0.011), had lower prestroke mRS, and smaller median core volumes (92 [79-116.5] mL vs 105.5 [85.75-138] mL, p = 0.004). EVT-treated patients had higher odds of achieving fair outcome in adjusted analysis (30% vs 13.9% in the non-EVT group; adjusted odds ratio [aOR] 2.1, 95% CI 1-4.2, p = 0.038). The benefit was seen predominantly in those with 70-100 mL core volume (71/135 [52.6%] EVT-treated), with 54.3% in the EVT-treated vs 21% in the non-EVT group achieving a fair outcome (aOR 2.5, 95% CI 1-6.2, p = 0.005). Of those with a core volume ≥100 mL, 50 of the 134 (37.3%) underwent EVT. Proportions of fair outcome were very low in both groups (8.1% vs 8.7%; p = 0.908). DISCUSSION: We found a positive association of EVT with the 3-month outcome after stroke in patients with a baseline CTP ischemic core volume 70-100 mL but not

Background: To compare the cost-effectiveness of providing endovascular thrombectomy (EVT) for patients with ischemic stroke in the >4.5h time window between patient groups who met and did not meet the perfusion imaging trial criteria. Methods: A discrete event simulation (DES) model was developed to simulate the long-term outcome post EVT in patients meeting or not meeting the extended time window clinical trial perfusion imaging criteria at presentation, vs. medical treatment alone (including intravenous thrombolysis). The effectiveness of thrombectomy in patients meeting the landmark trial criteria (DEFUSE 3 and DAWN) was derived from a prospective cohort study of Australian patients who received EVT for ischemic stroke, between 2015 and 2019, in the extended time window (>4.5 h). Results: Endovascular thrombectomy was shown to be a cost-effective treatment for patients satisfying the clinical trial criteria in our prospective cohort [incremental cost-effectiveness ratio (ICER) of $11,608/quality-adjusted life year (QALY) for DEFUSE 3-postive or $34,416/QALY for DAWN-positive]. However, offering EVT to patients outside of clinical trial criteria was associated with reduced benefit (−1.02 QALY for DEFUSE 3; −1.43 QALY for DAWN) and higher long-term patient costs ($8,955 for DEFUSE 3; $9,271 for DAWN), thereby making it unlikely to be cost-effective in Australia. Conclusions: Treating patients not meeting the DAWN or DEFUSE 3 clinical trial criteria in the extended time window for EVT was associated with less gain in QALYs and higher cost. Caution should be exercised when considering this procedure for patients not satisfying the trial perfusion imaging criteria for EVT.

Background: To compare the cost-effectiveness of providing endovascular thrombectomy (EVT) for patients with ischemic stroke in the >4.5 h time window between patient groups who met and did not meet the perfusion imaging trial criteria. Methods: A discrete event simulation (DES) model was developed to simulate the long-term outcome post EVT in patients meeting or not meeting the extended time window clinical trial perfusion imaging criteria at presentation, vs. medical treatment alone (including intravenous thrombolysis). The effectiveness of thrombectomy in patients meeting the landmark trial criteria (DEFUSE 3 and DAWN) was derived from a prospective cohort study of Australian patients who received EVT for ischemic stroke, between 2015 and 2019, in the extended time window (>4.5 h). Results: Endovascular thrombectomy was shown to be a cost-effective treatment for patients satisfying the clinical trial criteria in our prospective cohort [incremental cost-effectiveness ratio (ICER) of $11,608/quality-adjusted life year (QALY) for DEFUSE 3-postive or $34,416/QALY for DAWN-positive]. However, offering EVT to patients outside of clinical trial criteria was associated with reduced benefit (-1.02 QALY for DEFUSE 3; -1.43 QALY for DAWN) and higher long-term patient costs ($8,955 for DEFUSE 3; $9,271 for DAWN), thereby making it unlikely to be cost-effective in Australia. Conclusions: Treating patients not meeting the DAWN or DEFUSE 3 clinical trial criteria in the extended time window for EVT was associated with less gain in QALYs and higher cost. Caution should be exercised when considering this procedure for patients not satisfying the trial perfusion imaging criteria for EVT.

Introduction: A telestroke network in Northern New South Wales, Australia has been developed since 2017. We theorized that the telestroke network development would drive a progressive improvement in stroke care metrics over time. Aim: This study aimed to describe changes in acute stroke workflow metrics over time to determine whether they improved with network experience. Methods: We prospectively collected data of patients assessed by telestroke who received multimodal computed tomography (mCT) and were diagnosed with ischemic stroke or transient ischemic attack from January 2017 to July 2019. The period was divided into two phases (phase 1: January 2017 - October 2018 and phase 2: November 2018 - July 2019). We compared median door-to-call, door-to-image, and door-to-decision time between the two phases. Results: We included 433 patients (243 in phase 1 and 190 in phase 2). Each spoke site treated 1.5-5.2 patients per month. There were Door-to-call time (median 39 in phase 1, 35 min in phase 2, p = 0.18), and door-to-decision time (median 81.5 vs. 83 min, p = 0.31) were not improved significantly. Similarly, in the reperfusion therapy subgroup, door-to-call time (median 29 vs. 24.5 min, p = 0.12) and door-to-decision time (median 70.5 vs. 67.5 min, p = 0.75) remained substantially unchanged. Regression analysis showed no association between time in the network and door-to-decision time (coefficient 1.5, p = 0.32). Conclusion: In our telestroke network, acute stroke timing metrics did not improve over time. There is the need for targeted education and training focusing on both stroke reperfusion competencies and the technical aspects of telestroke in areas with limited workforce and high turnover.

Background: Intravenous thrombolytic therapy (IVT) with tissue plasminogen activator for acute ischemic stroke is underutilized in many parts of the world. Randomized trials to test the effectiveness of thrombolysis implementation strategies are limited. Methods and Results: This study aimed to test the effectiveness of a multicomponent, multidisciplinary tissue plasminogen activator implementation package in increasing the proportion of thrombolyzed cases while maintaining accepted benchmarks for low rates of intracranial hemorrhage and high rates of functional outcomes at 3 months. A cluster randomized controlled trial of 20 hospitals in the early stages of thrombolysis implementation across 3 Australian states was undertaken. Monitoring of IVT rates during the baseline period allowed hospitals (the unit of randomization) to be grouped into 3 baseline IVT strata—very low rates (0% to ≤4.0%); low rates (>4.0% to ≤10.0%); and moderate rates (>10.0%). Hospitals were randomized to an implementation package (experimental group) or usual care (control group) using a 1:1 ratio. The 16-month intervention was based on behavioral theory and analysis of the steps, roles, and barriers to rapid assessment for thrombolysis eligibility and involved comprehensive strategies addressing individual and system-level change. The primary outcome was the difference in tissue plasminogen activator proportions between the 2 groups postintervention. The absolute difference in postintervention IVT rates between intervention and control hospitals adjusted for baseline IVT rate and stratum was not significant (primary outcome rate difference=1.1% (95% CI −1.5% to 3.7%; P=0.38). Rates of intracranial hemorrhage remained below international benchmarks. Conclusions: The implementation package resulted in no significant change in tissue plasminogen activator implementation, suggesting that ongoing support is needed to sustain initial modifications in behavior. Clinical Trial Registration: URL: ww

Background and Purpose: Telestroke aims to increase access to endovascular clot retrieval (ECR) for rural areas. There is limited information on transfer workflow for ECR in rural settings. We sought to describe the transfer metrics for ECR in a rural telestroke network with respect to decision making. Methods: A retrospective cohort study was employed on consecutive patients transferred to the comprehensive stroke center (CSC) for ECR in a rural hub-and-spoke telestroke network between April 2013 and October 2019, by road or air. Key time-based metrics were analyzed. Results: Sixty-two patients were included. Mean age was 66 years [standard deviation (SD), 14] and median National Institutes of Health Stroke Scale 13 [interquartile range (IQR), 8-18]. Median rural-hospital-door-to-CSC-door (D2D) was 308 min (IQR, 254-351), of which 68% was spent at rural hospitals [door-in-door-out (DIDO); 214 min; IQR, 171-247]. DIDO was longer for air transfers than road (P = 0.004), primarily because of a median 87 min greater decision-to-departure time (Decision-DO, P < 0.001). In multiple linear regression analysis, intubation but not thrombolysis was associated with significantly longer DIDO. The distance at which the extra speed of an aircraft made up for the delays involved in booking an aircraft was 299 km from the CSC. Conclusions: DIDO is longer for air retrievals compared with road. Decision-DO represents the most important component of DIDO, being longer for air transfers. Systems for rapid transportation of rural ECR candidates need optimization for best patient outcomes, with decision support seen as a potential tool to achieve this.

Background: Admission outside normal business hours has been associated with prolonged door-to-treatment times and poorer patient outcomes, the so called "weekend effect. " This is the first examination of the weekend effect in a telestroke service that uses multi-modal computed tomography. Aims: To examine differences in workflow and triage between in-hours and out-of-hours calls to a telestroke service. Methods: All patients assessed using the Northern New South Wales (N-NSW) telestroke service from April 2013 to January 2019 were eligible for inclusion (674 in total; 539 with complete data). The primary outcomes measured were differences between in-hours and out-of-hours in door-to-call-to-decision-to-needle times, differences in the proportion of patients confirmed to have strokes or of patients selected for reperfusion therapies or patients with a modified Rankin Score (mRS ≤ 2) at 90 days. Results: There were no significant differences between in-hours and out-of-hours in any of the measured times, nor in the proportions of patients confirmed to have strokes (67.6 and 69.6%, respectively, p = 0.93); selected for reperfusion therapies (22.7 and 22.6%, respectively, p = 0.56); or independent at 3 months (34.8 and 33.6%, respectively, p = 0.770). There were significant differences in times between individual hospitals, and patient presentation more than 4.5 h after symptom onset was associated with slower times (21 minute delay in door-to-call, p = 0.002 and 22 min delay in door-to-image, p = 0.001). Conclusions: The weekend effect is not evident in the Northern NSW telestroke network experience, though this study did identify some opportunities for improvement in the delivery of acute stroke therapies.

AIMS: Penumbral selection is best-evidence practice for thrombectomy in the 6-24 hour window. Moreover, it helps to identify the best responders to thrombolysis. Multimodal computed tomography (mCT) at the primary centre-including noncontrast CT, CT perfusion, and CT angiography-may enhance reperfusion therapy decision-making. We developed a network with five spoke primary stroke sites and assessed safety, feasibility, and influence of mCT in rural hospitals on decision-making for thrombolysis. METHODS: Consecutive patients assessed via telemedicine from April 2013 to June 2018. Clinical outcomes were measured, and decision-making compared using theoretical models for reperfusion therapy applied without mCT guidance. Symptomatic intracranial hemorrhage (sICH) was assessed according to Safe Implementation of Treatments in Stroke Thrombolysis Registry criteria. RESULTS: A total of 334 patients were assessed, 240 received mCT, 58 were thrombolysed (24.2%). The mean age of thrombolysed patients was 70 years, median baseline National Institutes of Health Stroke Scale was 10 (IQR 7-18) and 23 (39.7%) had a large vessel occlusion. 1.7% had sICH and 3.5% parenchymal hematoma. Three months poststroke, 55% were independent, compared with 70% in the non-thrombolysed group. CONCLUSION: Implementation of CTP in rural centers was feasible and led to high thrombolysis rates with low rates of sICH.

Intravenous infusion of alteplase is used for thrombolysis before endovascular thrombectomy for ischemic stroke. Tenecteplase, which is more fibrin-specific and has longer activity than alteplase, is given as a bolus and may increase the incidence of vascular reperfusion. METHODS We randomly assigned patients with ischemic stroke who had occlusion of the internal carotid, basilar, or middle cerebral artery and who were eligible to undergo thrombectomy to receive tenecteplase (at a dose of 0.25 mg per kilogram of body weight; maximum dose, 25 mg) or alteplase (at a dose of 0.9 mg per kilogram; maximum dose, 90 mg) within 4.5 hours after symptom onset. The primary outcome was reperfusion of greater than 50% of the involved ischemic territory or an absence of retrievable thrombus at the time of the initial angiographic assessment. Noninferiority of tenecteplase was tested, followed by superiority. Secondary outcomes included the modified Rankin scale score (on a scale from 0 [no neurologic deficit] to 6 [death]) at 90 days. Safety outcomes were death and symptomatic intracerebral hemorrhage. RESULTS Of 202 patients enrolled, 101 were assigned to receive tenecteplase and 101 to receive alteplase. The primary outcome occurred in 22% of the patients treated with tenecteplase versus 10% of those treated with alteplase (incidence difference, 12 percentage points; 95% confidence interval [CI], 2 to 21; incidence ratio, 2.2; 95% CI, 1.1 to 4.4; P=0.002 for noninferiority; P=0.03 for superiority). Tenecteplase resulted in a better 90-day functional outcome than alteplase (median modified Rankin scale score, 2 vs. 3; common odds ratio, 1.7; 95% CI, 1.0 to 2.8; P=0.04). Symptomatic intracerebral hemorrhage occurred in 1% of the patients in each group. CONCLUSIONS Tenecteplase before thrombectomy was associated with a higher incidence of reperfusion and better functional outcome than alteplase among patients with ischemic stroke treated within 4.5 hours after symptom onset.Copyri

Background and hypothesis: Intravenous thrombolysis with alteplase remains standard care prior to thrombectomy for eligible patients within 4.5 h of ischemic stroke onset. However, alteplase only succeeds in reperfusing large vessel arterial occlusion prior to thrombectomy in a minority of patients. We hypothesized that tenecteplase is non-inferior to alteplase in achieving reperfusion at initial angiogram, when administered within 4.5 h of ischemic stroke onset, in patients planned to undergo endovascular therapy. Study design: EXTEND-IA TNK is an investigator-initiated, phase II, multicenter, prospective, randomized, open-label, blinded-endpoint non-inferiority study. Eligibility requires a diagnosis of ischemic stroke within 4.5 h of stroke onset, pre-stroke modified Rankin Scale<=3 (no upper age limit), large vessel occlusion (internal carotid, basilar, or middle cerebral artery) on multimodal computed tomography and absence of contraindications to intravenous thrombolysis. Patients are randomized to either IV alteplase (0.9 mg/kg, max 90 mg) or tenecteplase (0.25 mg/kg, max 25 mg) prior to thrombectomy. Study outcomes: The primary outcome measure is reperfusion on the initial catheter angiogram, assessed as modified treatment in cerebral infarction 2 b/3 or the absence of retrievable thrombus. Secondary outcomes include modified Rankin Scale at day 90 and favorable clinical response (reduction in National Institutes of Health Stroke Scale by >=8 points or reaching 0-1) at day 3. Safety outcomes are death and symptomatic intracerebral hemorrhage. Trial registration: ClinicalTrials.gov NCT02388061.Copyright © 2017, © 2017 World Stroke Organization.

AIM: The relative prognostic importance of modern imaging profiles compared with standard clinical characteristics is uncertain in acute stroke patients. In this study, we aimed to compare baseline multimodal CT imaging measures with known clinical predictors of patient outcome at 3 months [modified Rankin scale (mRS)]. METHODS: We collected baseline, 24 h, and day 90 clinical and imaging data from acute ischemic stroke patients being assessed for thrombolytic therapy between 2010 and 2015 at a single center as part of a retrospective analysis. RESULTS: 561 patients presenting within 4.5 h of ischemic stroke onset who were eligible for thrombolysis based on standard clinical criteria were assessed. Acute infarct core volume on CTP was the strongest univariate predictor of patient outcome (mRS 0-2, R2 0.497, p < 0.001), followed by collateral grade (mRS 0-2, R2 0.281, p < 0.001). The strongest baseline clinical predictor of outcome was National Institutes of Health Stroke Scale (NIHSS) (mRS 0-2, R2 = 0.203, p < 0.001). Time to treatment (mRS 0-2, R2 0.096, p = 0.01) and age (mRS 0-2, R2 0.027, p = 0.013) were relatively weak univariate baseline clinical predictors of 3-month outcome. In multivariate analysis, acute infarct core volume and collateral grade were the only significant baseline predictors of 3-month disability (both p < 0.001). CONCLUSION: In patients assessed for thrombolysis by combined clinical and multimodal CT criteria within 4.5 h of onset, the size of the CTP infarct core and collateral grade on multimodal CT were highly predictive of patient outcome. Standard clinical variables, including time to treatment and NIHSS, were not as strongly predictive as multimodal CT variables.

Introduction: We aimed to identify whether acute ischemic stroke patients with known complete reperfusion after thrombectomy had the same baseline computed tomography perfusion (CTP) ischemic core threshold to predict infarction as thrombolysis patients with complete reperfusion. Methods: Patients who underwent thrombectomy were matched by age, clinical severity, occlusion location, and baseline perfusion lesion volume to patients who were treated with intravenous alteplase alone from the International Stroke Perfusion Imaging Registry. A pixel-based analysis of coregistered pretreatment CTP and 24-hour diffusion-weighted imaging (DWI) was then undertaken to define the optimum CTP thresholds for the ischemic core. Results: There were 132 eligible thrombectomy patients and 132 matched controls treated with alteplase alone. Baseline National Institutes of Health Stroke Scale (median, 15; interquartile range [IQR], 11–19), age (median, 65; IQR, 59–80), and time to intravenous treatment (median, 153 minutes; IQR, 82–315) were well matched (all p > 0.05). Despite similar baseline CTP ischemic core volumes using the previously validated measure (relative cerebral blood flow [rCBF], <30%), thrombectomy patients had a smaller median 24-hour infarct core of 17.3ml (IQR, 11.3–32.8) versus 24.3ml (IQR, 16.7–42.2; p = 0.011) in alteplase-treated controls. As a result, the optimal threshold to define the ischemic core in thrombectomy patients was rCBF <20% (area under the curve [AUC], 0.89; 95% CI, 0.84, 0.94), whereas in alteplase controls the optimal ischemic core threshold remained rCBF <30% (AUC, 0.83; 95% CI, 0.77, 0.85). Interpretation: Thrombectomy salvaged tissue with lower CBF, likely attributed to earlier reperfusion. For patients who achieve rapid reperfusion, a stricter rCBF threshold to estimate the ischemic core should be considered. Ann Neurol 2017;82:995–1003.

Background: Endovascular thrombectomy improves functional outcome in large vessel occlusion ischemic stroke. We examined disability, quality of life, survival and acute care costs in the EXTEND-IA trial, which used CT-perfusion imaging selection. Method(s): Large vessel ischemic stroke patients with favorable CT-perfusion were randomized to endovascular thrombectomy after alteplase versus alteplase-only. Clinical outcome was prospectively measured using 90-day modified Rankin scale (mRS). Individual patient expected survival and net difference in Disability/Quality-adjusted life years (DALY/QALY) up to 15 years from stroke were modeled using age, sex, 90-day mRS, and utility scores. Level of care within the first 90 days was prospectively measured and used to estimate procedure and inpatient care costs (US$ reference year 2014). Result(s): There were 70 patients, 35 in each arm, mean age 69, median NIHSS 15 (IQR 12-19). The median (IQR) disability-weighted utility score at 90 days was 0.65 (0.00-0.91) in the alteplase-only versus 0.91 (0.65-1.00) in the endovascular group (p = 0.005). Modeled life expectancy was greater in the endovascular versus alteplase-only group (median 15.6 versus 11.2 years, p = 0.02). The endovascular thrombectomy group had fewer simulated DALYs lost over 15 years [median (IQR) 5.5 (3.2-8.7) versus 8.9 (4.7-13.8), p = 0.02] and more QALY gained [median (IQR) 9.3 (4.2-13.1) versus 4.9 (0.3-8.5), p = 0.03]. Endovascular patients spent less time in hospital [median (IQR) 5 (3-11) days versus 8 (5-14) days, p = 0.04] and rehabilitation [median (IQR) 0 (0-28) versus 27 (0-65) days, p = 0.03]. The estimated inpatient costs in the first 90 days were less in the thrombectomy group (average US$15,689 versus US$30,569, p = 0.008) offsetting the costs of interhospital transport and the thrombectomy procedure (average US$10,515). The average saving per patient treated with thrombectomy was US$4,365. Conclusion(s): Thrombectomy patients with large vessel

BACKGROUND: Endovascular thrombectomy improves functional outcome in large vessel occlusion ischemic stroke. We examined disability, quality of life, survival and acute care costs in the EXTEND-IA trial, which used CT-perfusion imaging selection. METHODS: Large vessel ischemic stroke patients with favorable CT-perfusion were randomized to endovascular thrombectomy after alteplase versus alteplase-only. Clinical outcome was prospectively measured using 90-day modified Rankin scale (mRS). Individual patient expected survival and net difference in Disability/Quality-adjusted life years (DALY/QALY) up to 15 years from stroke were modeled using age, sex, 90-day mRS, and utility scores. Level of care within the first 90 days was prospectively measured and used to estimate procedure and inpatient care costs (US$ reference year 2014). RESULTS: There were 70 patients, 35 in each arm, mean age 69, median NIHSS 15 (IQR 12-19). The median (IQR) disability-weighted utility score at 90 days was 0.65 (0.00-0.91) in the alteplase-only versus 0.91 (0.65-1.00) in the endovascular group (p = 0.005). Modeled life expectancy was greater in the endovascular versus alteplase-only group (median 15.6 versus 11.2 years, p = 0.02). The endovascular thrombectomy group had fewer simulated DALYs lost over 15 years [median (IQR) 5.5 (3.2-8.7) versus 8.9 (4.7-13.8), p = 0.02] and more QALY gained [median (IQR) 9.3 (4.2-13.1) versus 4.9 (0.3-8.5), p = 0.03]. Endovascular patients spent less time in hospital [median (IQR) 5 (3-11) days versus 8 (5-14) days, p = 0.04] and rehabilitation [median (IQR) 0 (0-28) versus 27 (0-65) days, p = 0.03]. The estimated inpatient costs in the first 90 days were less in the thrombectomy group (average US$15,689 versus US$30,569, p = 0.008) offsetting the costs of interhospital transport and the thrombectomy procedure (average US$10,515). The average saving per patient treated with thrombectomy was US$4,365. CONCLUSION: Thrombectomy patients with large vessel occlus

Background: The use of advanced brain imaging to identify potentially salvageable ischemic penumbra has been controversial. We examined the effect of reperfusion on functional outcome in the EXTEND-IA trial. Method(s): Patients receiving tPA < 4.5 h with major vessel occlusion were randomized to thrombectomy versus tPA-only if CT-perfusion demonstrated mismatch ratio > 1.2 between hypoperfused tissue (Tmax > 6 s) and irreversibly injured ischemic core (relative cerebral blood flow < 30%), absolute mismatch > 10 mL and ischemic core < 70 mL (RAPID software, Stanford University). Reperfusion was defined as >90% reduction in Tmax > 6 s hypoperfusion volume between baseline and 24 h perfusion imaging. Modified Rankin Scale (mRS) was assessed at 90 days. Result(s): There were 70 patients, 35 in each arm, mean age 69, median NIHSS 15. Reperfusion of >90% of the affected territory occurred in 89% endovascular patients and 34% tPA-only patients (p < 0.001). Reperfusion was associated with independence (mRS0-2) in 72% versus 30% nonreperfused patients (p < 0.001). In ordinal analysis which assesses shift between individual levels of the mRS, the unadjusted generalized odds ratio = 4.5, 95%CI 2.2-9.0, p < 0.001 with a 'number needed to reperfuse' of 1.6 patients to achieve at least 1 point improvement on the mRS (OR = 5.1, p < 0.001, adjusted for age and NIHSS). Conclusion(s): In ischemic stroke patients with large vessel occlusion and 'target mismatch' indicating salvageable tissue on CT-perfusion, outcomes are usually unfavorable unless reperfusion is achieved with 70% of patients dead or dependent at 3 months. This is consistent with the penumbral hypothesis that, in the absence of reperfusion, penumbral tissue is recruited into the irreversibly injured infarct over time.

Background: The kidney-brain interaction has been a topic of growing interest. Past studies of the effect of kidney function on intracerebral hemorrhage (ICH) outcomes have yielded inconsistent findings. Although the second, main phase of the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial (INTERACT2) suggests the effectiveness of early intensive blood pressure (BP) lowering in improving functional recovery after ICH, the balance of potential benefits and harms of this treatment in those with decreased kidney function remains uncertain. Study Design: Secondary analysis of INTERACT2, which randomly assigned patients with ICH with elevated systolic BP (SBP) to intensive (target SBP < 140 mm Hg) or contemporaneous guideline-based (target SBP < 180 mm Hg) BP management. Setting & Participants: 2,823 patients from 144 clinical hospitals in 21 countries. Predictors Admission estimated glomerular filtration rates (eGFRs) of patients were categorized into 3 groups based on the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine equation: normal or high, mildly decreased, and moderately to severely decreased (>90, 60-90, and <60 mL/min/1.73 m2, respectively). Outcome(s): The effect of admission eGFR on the primary outcome of death or major disability at 90 days (defined as modified Rankin Scale scores of 3-6) was analyzed using a multivariable logistic regression model. Potential effect modification of intensive BP lowering treatment by admission eGFR was assessed by interaction terms. Result(s): Of 2,623 included participants, 912 (35%) and 280 (11%) had mildly and moderately/severely decreased eGFRs, respectively. Patients with moderately/severely decreased eGFRs had the greatest risk for death or major disability at 90 days (adjusted OR, 1.82; 95% CI, 1.28-2.61). Effects of early intensive BP lowering were consistent across different eGFRs (P = 0.5 for homogeneity). Limitation(s): Generalizability issues arising from a clinical tri

Background: Optimal imaging selection for endovascular therapy for ischemic stroke remains controversial with a range of criteria used in the recent positive trials. Large volume severe hypoperfusion (Tmax > 10 s) is one such criterion, with optimal threshold > 82 mL ('malignant profile'), in a previous study. We examined whether this was associated with poor response to reperfusion in the EXTEND-IA randomized trial, which did not exclude patients on this basis. Method(s): Patients receiving tPA < 4.5 h with major vessel occlusion and favorable CT-perfusion (CTP) were randomized (after written informed consent, IRB-approved) to thrombectomy after tPA versus tPA-alone. CTP eligibility required mismatch ratio > 1.2 between hypoperfused tissue (Tmax > 6 s) and irreversibly injured ischemic core (relative cerebral blood flow < 30%), absolute mismatch > 10 mL, ischemic core <70 mL (RAPID software, Stanford University). Tmax > 10 s volume was calculated and effect on clinical outcomes examined. Result(s): There were 70 patients, 35 in each arm, mean age = 69, median NIHSS = 15. In these patients with ischemic core < 70 mL, median Tmax > 10 s volume was 41 ml with 12/70(17%) > 82 ml, 6/70(8.6%) > 100 ml. Of the 'malignant' patients(Tmax10 s > 82 ml), 6/12(50%) had >90% reperfusion at 24 h (4 endovascular and 2 tPAonly), all of whom had 'early neurological recovery' (>=8 point NIHSS reduction or 0-1 by day 3) and 5/6(83%) had 90 day mRS0-1. No patient with <90% reperfusion had day 90 mRS < 3. Conclusion(s): In ischemic stroke patients <4.5 h after onset, large Tmax > 10 s volume in the absence of a large ischemic core was uncommon. Although the numbers in this study were small, the 83% rate of excellent functional outcome after reperfusion suggests that excluding such patients from therapy may not be justified.

Background: Recent trials have demonstrated improved outcomes with endovascular therapy for ischemic stroke compared with tPA. We examined the effects on resource utilization, length of stay and cost in the EXTEND-IA trial. Method(s): Patients receiving tPA < 4.5 h who had major vessel occlusion and CT-perfusion evidence of salvageable brain tissue were randomized to endovascular thrombectomy after tPA versus tPA-alone. Length of stay in acute inpatient, rehabilitation and nursing care units over the first 3 months and costs were compared between groups (Wilcoxon test) and the mean values were used to calculate costs for the average patient in each treatment group. Result(s): There were 70 patients, 35 in each arm, mean age 69, median NIHSS 15. Endovascular patients had shorter acute inpatient stays (mean 8 versus 12 days, p = 0.04) without increased time in intensive care (9 versus 11 hours, p = 0.51). Survivors spent less time in rehabilitation after endovascular treatment (mean 14 versus 33 days, p = 0.03). The cost of inpatient care in the first 3 months was similar for endovascular and tPA-only patients (mean AU$43,000 versus AU$45,000, respectively), including the AU$20,000 average cost for the thrombectomy. Ongoing nursing care (AU$146,000 p.a.) was required for 5/35 patients (all tPA-only). Conclusion(s): In ischemic stroke patients with large vessel occlusion and salvageable tissue on CT-perfusion, thrombectomy reduced length of stay and was cost neutral compared with tPA-alone over 3months. The healtheconomic benefits would be expected to increase further over time. The magnitude of difference in inpatient care costs suggests this finding would generalize to other health systems.

Background: Recent trials have demonstrated improved outcomes with endovascular therapy for ischemic stroke compared with tPA. We examined the effects on resource utilization, length of stay and cost of care in the EXTEND-IA randomized trial. Method(s): Patients receiving tPA < 4.5 h who had major vessel occlusion and CT-perfusion evidence of salvageable brain tissue were randomized (after written informed consent, IRB-approved) to endovascular thrombectomy after tPA versus tPA alone. Length of stay in acute inpatient, rehabilitation and nursing care units over the first 3 months and costs were compared between groups (Wilcoxon test). Result(s): There were 70 patients, 35 in each arm, mean age 69, median NIHSS 15. Endovascular patients had shorter acute inpatient stays (mean 8 versus 12 days, p = 0.04) without increased time in intensive care (9 versus 11 hours, p = 0.51). Survivors spent less time in rehabilitation after endovascular treatment (mean 14 versus 33 days, p = 0.03). The cost of inpatient care in the first 3 months was similar for endovascular and tPA-only patients (mean AU$43,000 versus AU$45,000, respectively), including the AU$20,000 average cost for the thrombectomy. Ongoing nursing care (AU$146,000p.a.) was required for 5/35 patients (all tPA-only). Conclusion(s): In ischemic stroke patients with a proximal cerebral arterial occlusion and salvageable tissue on CT-perfusion imaging, thrombectomy reduced length of stay and was cost neutral compared with tPA alone over 3 months. The health-economic benefits would be expected to increase further over time. The magnitude of difference in inpatient care costs suggests this finding would generalize to other health systems.

Background: The MR-RESCUE trial failed to demonstrate improved outcome with reperfusion in patients with a favorable imaging profile, casting doubts on the penumbral hypothesis. We examined the effect of reperfusion on functional outcome in the EXTEND-IA randomized trial. Method(s): Patients receiving tPA < 4.5 h with major vessel occlusion were randomized (after written informed consent, IRB-approved) to thrombectomy versus tPA-only if CT-perfusion demonstrated mismatch ratio>1.2 between hypoperfused tissue (Tmax > 6 s) and irreversibly injured ischemic core (relative cerebral blood flow <30%), absolute mismatch > 10 mL and ischemic core <70 mL (RAPID software, Stanford University). Reperfusion was defined as >90% reduction in Tmax > 6 s hypoperfusion volume between baseline and 24 h perfusion imaging. Modified Rankin Scale (mRS) was assessed at 90 days. Result(s): There were 70 patients, 35 in each arm, mean age 69, median NIHSS 15. Reperfusion of >90% of the affected territory occurred in 89% endovascular patients and 34% tPA-only patients (p < 0.001).Reperfusion was associated with independence (mRS0-2) in 72% versus 30% nonreperfused patients (p < 0.001) and in ordinal analysis, unadjusted generalized odds ratio = 4.5, 95% CI 2.2-9.0, p < 0.001, number needed to treat = 1.6 (OR = 5.1, p < 0.001, adjusted for age and NIHSS, Figure). (Figure presented) Conclusion(s): In ischemic stroke patients with a proximal cerebral arterial occlusion and 'target mismatch' indicating salvageable tissue on CT-perfusion imaging, outcomes are usually unfavorable unless reperfusion is achieved. Differences in mismatch definition and reperfusion assessment likely underlie the incongruent MR-RESCUE findings.

Background: Trials of endovascular therapy for ischemic stroke have produced variable results. We conducted this study to test whether more advanced imaging selection, recently developed devices, and earlier intervention improve outcomes. Method(s): We randomly assigned patients with ischemic stroke who were receiving 0.9 mg of alteplase per kilogram of body weight less than 4.5 hours after the onset of ischemic stroke either to undergo endovascular thrombectomy with the Solitaire FR (Flow Restoration) stent retriever or to continue receiving alteplase alone. All the patients had occlusion of the internal carotid or middle cerebral artery and evidence of salvageable brain tissue and ischemic core of less than 70 ml on computed tomographic (CT) perfusion imaging. The coprimary outcomes were reperfusion at 24 hours and early neurologic improvement (.8-point reduction on the National Institutes of Health Stroke Scale or a score of 0 or 1 at day 3). Secondary outcomes included the functional score on the modified Rankin scale at 90 days. Result(s): The trial was stopped early because of efficacy after 70 patients had undergone randomization (35 patients in each group). The percentage of ischemic territory that had undergone reperfusion at 24 hours was greater in the endovascular-therapy group than in the alteplase-only group (median, 100% vs. 37%; P<0.001). Endovascular therapy, initiated at a median of 210 minutes after the onset of stroke, increased early neurologic improvement at 3 days (80% vs. 37%, P = 0.002) and improved the functional outcome at 90 days, with more patients achieving functional independence (score of 0 to 2 on the modified Rankin scale, 71% vs. 40%; P = 0.01). There were no significant differences in rates of death or symptomatic intracerebral hemorrhage. Conclusion(s): In patients with ischemic stroke with a proximal cerebral arterial occlusion and salvageable tissue on CT perfusion imaging, early thrombectomy with the Solitaire FR stent retrieve

Background: Optimal imaging selection for endovascular therapy for ischemic stroke remains controversial with a range of criteria used in the recent positive trials. Large volume severe hypoperfusion (Tmax > 10 s) is one such criterion, with optimal threshold > 82 mL ('malignant profile'), in a previous study. We examined whether this was associated with poor response to reperfusion in the EXTEND-IA randomized trial, which did not exclude patients on this basis. Method(s): Patients receiving tPA < 4.5 h with major vessel occlusion and favourable CT-perfusion (CTP) were randomised (after written informed consent, IRB-approved) to thrombectomy after tPA versus tPA-alone. CTP eligibility required mismatch ratio > 1.2 between hypoperfused tissue (Tmax > 6 s) and irreversibly injured ischemic core (relative cerebral blood flow <30%), absolute mismatch > 10 mL, ischemic core <70 mL (RAPID software, Stanford University). Tmax > 10 s volume was calculated and effect on clinical outcomes examined. Result(s): There were 70 patients, 35 in each arm, mean age = 69, median NIHSS = 15. In these patients with ischemic core <70 mL, median Tmax > 10 s volume was 41 mL with 12/70(17%) > 82 mL, 6/70(8.6%) > 100 mL. Of the 'malignant' patients(Tmax10s > 82 mL), 6/12(50%) had >90% reperfusion at 24 h (4 endovascular and 2 tPAonly), all of whom had 'early neurological recovery' (>=8 point NIHSS reduction or 0-1 by day 3) and 5/6(83%) had 90 day mRS0-1. No patient with <90% reperfusion had day 90 mRS < 3. Conclusion(s): In ischemic stroke patients <4.5 h after onset, large Tmax > 10 s volume in the absence of a large ischemic core was uncommon. Although the numbers in this study were small, the 83% rate of excellent functional outcome after reperfusion suggests that excluding such patients from therapy may not be justified.

The use of perfusion imaging to guide selection of patients for stroke thrombolysis remains controversial because of lack of supportive phase three clinical trial evidence. We aimed to measure the outcomes for patients treated with intravenous recombinant tissue plasminogen activator (rtPA) at a comprehensive stroke care facility where perfusion computed tomography was routinely used for thrombolysis eligibility decision assistance. Our overall hypothesis was that patients with 'target' mismatch on perfusion computed tomography would have improved outcomes with rtPA. This was a prospective cohort study of consecutive ischaemic stroke patients who fulfilled standard clinical/non-contrast computed tomography eligibility criteria for treatment with intravenous rtPA, but for whom perfusion computed tomography was used to guide the final treatment decision. The 'real-time' perfusion computed tomography assessments were qualitative; a large perfusion computed tomography ischaemic core, or lack of significant perfusion lesion-core mismatch were considered relative exclusion criteria for thrombolysis. Specific volumetric perfusion computed tomography criteria were not used for the treatment decision. The primary analysis compared 3-month modified Rankin Scale in treated versus untreated patients after 'off-line' (post-treatment) quantitative volumetric perfusion computed tomography eligibility assessment based on presence or absence of 'target' perfusion lesion-core mismatch (mismatch ratio >1.8 and volume >15 ml, core <70 ml). In a second analysis, we compared outcomes of the perfusion computed tomography-selected rtPA-treated patients to an Australian historical cohort of non-contrast computed tomography-selected rtPA-treated patients. Of 635 patients with acute ischaemic stroke eligible for rtPA by standard criteria, thrombolysis was given to 366 patients, with 269 excluded based on visual real-time perfusion computed tomography assessment. After off-line quantitative pe

Background and Hypothesis: Thrombolysis with tissue plasminogen activator is proven to reduce disability when given within 4.5h of ischemic stroke onset. However, tissue plasminogen activator only succeeds in recanalizing large vessel arterial occlusion in a minority of patients. We hypothesized that anterior circulation ischemic stroke patients, selected with 'dual target' vessel occlusion and evidence of salvageable brain using computed tomography or magnetic resonance imaging 'mismatch' within 4.5h of onset, would have improved reperfusion and early neurological improvement when treated with intra-arterial clot retrieval after intravenous tissue plasminogen activator compared with intravenous tissue plasminogen activator alone. Study Design: EXTEND-IA is an investigator-initiated, phase II, multicenter prospective, randomized, open-label, blinded-endpoint study. Ischemic stroke patients receiving standard 0.9mg/kg intravenous tissue plasminogen activator within 4.5h of stroke onset who have good prestroke functional status (modified Rankin Scale <2, no upper age limit) will undergo multimodal computed tomography or magnetic resonance imaging. Patients who also meet dual target imaging criteria: vessel occlusion (internal carotid or middle cerebral artery) and mismatch (perfusion lesion:ischemic core mismatch ratio >1.2, absolute mismatch >10ml, ischemic core volume <70ml) will be randomized to either clot retrieval with the Solitaire FR device after full dose intravenous tissue plasminogen activator, or tissue plasminogen activator alone. Study Outcomes: The coprimary outcome measure will be reperfusion at 24h and favorable clinical response (reduction in National Institutes of Health Stroke Scale by >=8 points or reaching 0-1) at day 3. Secondary outcomes include modified Rankin Scale at day 90, death, and symptomatic intracranial hemorrhage. © 2013 World Stroke Organization.