Ultra-Long Transfers for Endovascular Thrombectomy-Mission Impossible?: The Australia-New Zealand Experience.

BACKGROUND: Endovascular thrombectomy (EVT) access in remote areas is limited. Preliminary data suggest that long distance transfers for EVT may be beneficial; however, the magnitude and best imaging strategy at the referring center remains uncertain. We hypothesized that patients transferred >300 miles would benefit from EVT, achieving rates of functional independence (modified Rankin Scale [mRS] score of 0-2) at 3 months similar to those patients treated at the comprehensive stroke center in the randomized EVT extended window trials and that the selection of patients with computed tomography perfusion (CTP) at the referring site would be associated with ordinal shift toward better outcomes on the mRS. METHODS: This is a retrospective analysis of patients transferred from 31 referring hospitals >300 miles (measured by the most direct road distance) to 9 comprehensive stroke centers in Australia and New Zealand for EVT consideration (April 2016 through May 2021). RESULTS: There were 131 patients; the median age was 64 [53-74] years and the median baseline National Institutes of Health Stroke Scale score was 16 [12-22]. At baseline, 79 patients (60.3%) had noncontrast CT+CT angiography, 52 (39.7%) also had CTP. At the comprehensive stroke center, 114 (87%) patients underwent cerebral angiography, and 96 (73.3%) proceeded to EVT. At 3 months, 62 patients (48.4%) had an mRS score of 0 to 2 and 81 (63.3%) mRS score of 0 to 3. CTP selection at the referring site was not associated with better ordinal scores on the mRS at 3 months (mRS median of 2 [1-3] versus 3 [1-6] in the patients selected with noncontrast CT+CT angiography, P=0.1). Nevertheless, patients selected with CTP were less likely to have an mRS score of 5 to 6 (odds ratio 0.03 [0.01-0.19]; P<0.01). CONCLUSIONS: In selected patients transferred >300 miles, there was a benefit for EVT, with outcomes similar to those treated in the comprehensive stroke center in the EVT extended window trials. Remote hospital CTP selection was not associated with ordinal mRS improvement, but was associated with fewer very poor 3-month outcomes.

Ischemic core thresholds change with time to reperfusion: A case control study.

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.

Evaluation of a CTA-Triage Based Transient Ischemic Attack Service: A Retrospective Single Center Cohort Study.

OBJECTIVE: We designed a computed tomography angiography (CTA)-based algorithm for patients presenting to hospital with a transient ischemic attack (TIA) which identified high-risk patients, as well as inpatient versus semiurgent outpatient management following MRI, and we hypothesised that this would be effective. METHODS: Patients seen in the ED at the Royal Adelaide Hospital from March 3, 2012 to November 30, 2016 with TIA-like symptoms were assessed for a cardioembolic source (clinical assessment, electrocardiogram) and underwent intra and extracranial CTA. Patients with a referable >50% stenosis were admitted and given dual antiplatelets. Most high-risk cardiac source patients were also admitted and anticoagulated. Other patients were loaded with aspirin, or changed to clopidogrel if on aspirin, and reviewed as outpatients following semiurgent MRI (3-4 days). We assessed the 90-day recurrent stroke risk in this cohort as a whole, and in those with a final cerebrovascular diagnosis. RESULTS: 1167 patients were diagnosed in Emergency as TIA and referred via our algorithm. A total of 150 were admitted, 78 had "high-risk" features. A total of 1017 patients were reviewed in the TIA clinic. The average age of the total cohort was 65.8 years old. Final diagnosis was TIA/minor stroke in 69% admitted patients and 30% clinic patients (P value < .0001). The 90-day recurrent stroke risk in these patients was 2.0% (5.8% admitted vs .7% clinic patients, P value < .0001). In those with noncerebrovascular diagnoses, there were no recurrent strokes within 90 days. CONCLUSIONS: Stroke risk is very low using CTA guided semiurgent clinic review algorithm.

Validating a Predictive Model of Acute Advanced Imaging Biomarkers in Ischemic Stroke.

BACKGROUND AND PURPOSE: Advanced imaging to identify tissue pathophysiology may provide more accurate prognostication than the clinical measures used currently in stroke. This study aimed to derive and validate a predictive model for functional outcome based on acute clinical and advanced imaging measures. METHODS: A database of prospectively collected sub-4.5 hour patients with ischemic stroke being assessed for thrombolysis from 5 centers who had computed tomographic perfusion and computed tomographic angiography before a treatment decision was assessed. Individual variable cut points were derived from a classification and regression tree analysis. The optimal cut points for each assessment variable were then used in a backward logic regression to predict modified Rankin scale (mRS) score of 0 to 1 and 5 to 6. The variables remaining in the models were then assessed using a receiver operating characteristic curve analysis. RESULTS: Overall, 1519 patients were included in the study, 635 in the derivation cohort and 884 in the validation cohort. The model was highly accurate at predicting mRS score of 0 to 1 in all patients considered for thrombolysis therapy (area under the curve [AUC] 0.91), those who were treated (AUC 0.88) and those with recanalization (AUC 0.89). Next, the model was highly accurate at predicting mRS score of 5 to 6 in all patients considered for thrombolysis therapy (AUC 0.91), those who were treated (0.89) and those with recanalization (AUC 0.91). The odds ratio of thrombolysed patients who met the model criteria achieving mRS score of 0 to 1 was 17.89 (4.59-36.35, P<0.001) and for mRS score of 5 to 6 was 8.23 (2.57-26.97, P<0.001). CONCLUSIONS: This study has derived and validated a highly accurate model at predicting patient outcome after ischemic stroke.

Too good to treat? ischemic stroke patients with small computed tomography perfusion lesions may not benefit from thrombolysis.

OBJECTIVE: Although commonly used in clinical practice, there remains much uncertainty about whether perfusion computed tomography (CTP) should be used to select stroke patients for acute reperfusion therapy. In this study, we tested the hypothesis that a small acute perfusion lesion predicts good clinical outcome regardless of thrombolysis administration. METHODS: We used a prospectively collected cohort of acute ischemic stroke patients being assessed for treatment with IV-alteplase, who had CTP before a treatment decision. Volumetric CTP was retrospectively analyded to identify patients with a small perfusion lesion (<15ml in volume). The primary analysis was excellent 3-month outcome in patients with a small perfusion lesion who were treated with alteplase compared to those who were not treated. RESULTS: Of 1526 patients, 366 had a perfusion lesion <15ml and were clinically eligible for alteplase (212 being treated and 154 not treated). Median acute National Institutes of Health Stroke Scale score was 8 in each group. Of the 366 patients with a small perfusion lesion, 227 (62%) were modified Rankin Scale (mRS) 0 to 1 at day 90. Alteplase-treated patients were less likely to achieve 90-day mRS 0 to 1 (57%) than untreated patients (69%; relative risk [RR] = 0.83; 95% confidence interval [CI], 0.71-0.97; p = 0.022) and did not have different rates of mRS 0 to 2 (72% treated patients vs 77% untreated; RR, 0.93; 95% CI, 0.82-1.95; p = 0.23). INTERPRETATION: This large observational cohort suggests that a portion of ischemic stroke patients clinically eligible for alteplase therapy with a small perfusion lesion have a good natural history and may not benefit from treatment. Ann Neurol 2016;80:286-293.

Machine learning segmentation of core and penumbra from acute stroke CT perfusion data.

Introduction: Computed tomography perfusion (CTP) imaging is widely used in cases of suspected acute ischemic stroke to positively identify ischemia and assess suitability for treatment through identification of reversible and irreversible tissue injury. Traditionally, this has been done via setting single perfusion thresholds on two or four CTP parameter maps. We present an alternative model for the estimation of tissue fate using multiple perfusion measures simultaneously. Methods: We used machine learning (ML) models based on four different algorithms, combining four CTP measures (cerebral blood flow, cerebral blood volume, mean transit time and delay time) plus 3D-neighborhood (patch) analysis to predict the acute ischemic core and perfusion lesion volumes. The model was developed using 86 patient images, and then tested further on 22 images. Results: XGBoost was the highest-performing algorithm. With standard threshold-based core and penumbra measures as the reference, the model demonstrated moderate agreement in segmenting core and penumbra on test images. Dice similarity coefficients for core and penumbra were 0.38 ± 0.26 and 0.50 ± 0.21, respectively, demonstrating moderate agreement. Skull-related image artefacts contributed to lower accuracy. Discussion: Further development may enable us to move beyond the current overly simplistic core and penumbra definitions using single thresholds where a single error or artefact may lead to substantial error.

Optimal CT perfusion thresholds for core and penumbra in acute posterior circulation infarction.

Background: At least 20% of strokes involve the posterior circulation (PC). Compared to the anterior circulation, posterior circulation infarction (POCI) are frequently misdiagnosed. CT perfusion (CTP) has advanced stroke care by improving diagnostic accuracy and expanding eligibility for acute therapies. Clinical decisions are predicated upon precise estimates of the ischaemic penumbra and infarct core. Current thresholds for defining core and penumbra are based upon studies of anterior circulation stroke. We aimed to define the optimal CTP thresholds for core and penumbra in POCI. Methods: Data were analyzed from 331-patients diagnosed with acute POCI enrolled in the International-stroke-perfusion-registry (INSPIRE). Thirty-nine patients with baseline multimodal-CT with occlusion of a large PC-artery and follow up diffusion weighted MRI at 24-48 h were included. Patients were divided into two-groups based on artery-recanalization on follow-up imaging. Patients with no or complete recanalisation were used for penumbral and infarct-core analysis, respectively. A Receiver operating curve (ROC) analysis was used for voxel-based analysis. Optimality was defined as the CTP parameter and threshold which maximized the area-under-the-curve. Linear regression was used for volume based analysis determining the CTP threshold which resulted in the smallest mean volume difference between the acute perfusion lesion and follow up MRI. Subanalysis of PC-regions was performed. Results: Mean transit time (MTT) and delay time (DT) were the best CTP parameters to characterize ischaemic penumbra (AUC = 0.73). Optimal thresholds for penumbra were a DT >1 s and MTT>145%. Delay time (DT) best estimated the infarct core (AUC = 0.74). The optimal core threshold was a DT >1.5 s. The voxel-based analyses indicated CTP was most accurate in the calcarine (Penumbra-AUC = 0.75, Core-AUC = 0.79) and cerebellar regions (Penumbra-AUC = 0.65, Core-AUC = 0.79). For the volume-based analyses, MTT >160% demonstrated best correlation and smallest mean-volume difference between the penumbral estimate and follow-up MRI (R 2 = 0.71). MTT >170% resulted in the smallest mean-volume difference between the core estimate and follow-up MRI, but with poor correlation (R 2 = 0.11). Conclusion: CTP has promising diagnostic utility in POCI. Accuracy of CTP varies by brain region. Optimal thresholds to define penumbra were DT >1 s and MTT >145%. The optimal threshold for core was a DT >1.5 s. However, CTP core volume estimates should be interpreted with caution.

A population-based study of thrombolysis for acute stroke in South Australia.

OBJECTIVE: To report the rate of thrombolysis for treating acute stroke in South Australia from October 2007 to September 2009. We hypothesised that the rate of thrombolytic therapy would be related to distance from an acute stroke unit. DESIGN, SETTING AND PATIENTS: An observational, population-based, retrospective review of case notes and imaging, using multiple case-ascertainment methods. Patients administered a thrombolytic agent by any method for suspected ischaemic stroke in urban, rural, public and private hospitals in SA (covering a population of 1.5 million people) were included. MAIN OUTCOME MEASURES: Absolute and relative contraindications for thrombolysis administration in each case, according to the 2007 National Stroke Foundation guidelines; incidence of haemorrhage; and population thrombolysis rates according to distance from an acute stroke unit. RESULTS: A total of 158 cases of thrombolytic therapy for suspected acute ischaemic stroke were identified in 157 patients. Fifteen patients (10%) had symptomatic intracranial haemorrhage, of whom eight (5%) died within 3 months. Seven patients had symptomatic extracranial haemorrhage. Five patients (3%) received thrombolysis despite absolute contraindications. Patients living closer to stroke units were more likely to receive thrombolysis. CONCLUSIONS: Rates of symptomatic haemorrhage after thrombolysis were similar to those in voluntary registries. A large proportion of South Australians are currently missing out on acute stroke therapy as a result of poor access to acute stroke units in both urban and rural settings. It is estimated that fewer than 2% of ischaemic stroke patients are administered thrombolysis in SA.

Ischaemic stroke among young people aged 15 to 50 years in Adelaide, South Australia.

OBJECTIVES: To report risk factors, aetiology and neuroimaging features among a large series of young Australian patients who were admitted to hospital for a first-ever occurrence of ischaemic stroke; to analyse the effect of age, sex and ethnicity on the presence of risk factors; and to compare Australian and overseas data. DESIGN, SETTING AND PATIENTS: Retrospective evaluation of data for all patients aged from 15 to 50 years who were admitted to a public hospital in Adelaide, South Australia, from January 2006 to June 2010 with a primary diagnosis of ischaemic stroke. RESULTS: Among 326 patients (184 males), the most frequent stroke risk factors overall were dyslipidaemia (187), smoking (161), hypertension (105) and obesity (92). Fifty-one patients used illicit drugs, mostly comprising marijuana and amphetamines. The most frequent stroke aetiologies overall were cardioembolism (85), arterial dissection (49), and small-vessel occlusion (31). Cardioembolism was highly prevalent among our study population compared with patients in other countries. Neuroimaging showed that more patients in our study had strokes that involved both vascular territories concurrently (9%) compared with patients in other countries. CONCLUSIONS: Risk factors, aetiology and features of ischaemic stroke among young people in Adelaide differ significantly from published data for young patients around the world. Patients in Adelaide are more likely to be obese, to be misusing marijuana and amphetamines, to suffer a cardioembolic event and to have a stroke that concurrently affects both the anterior and posterior cerebral circulation.

Assessing the Relative Value of CT Perfusion Compared to Non-contrast CT and CT Angiography in Prognosticating Reperfusion-Eligible Acute Ischemic Stroke Patients.

In the present study we sought to measure the relative statistical value of various multimodal CT protocols at identifying treatment responsiveness in patients being considered for thrombolysis. We used a prospectively collected cohort of acute ischemic stroke patients being assessed for IV-alteplase, who had CT-perfusion (CTP) and CT-angiography (CTA) before a treatment decision. Linear regression and receiver operator characteristic curve analysis were performed to measure the prognostic value of models incorporating each imaging modality. One thousand five hundred and sixty-two sub-4.5 h ischemic stroke patients were included in this study. A model including clinical variables, alteplase treatment, and NCCT ASPECTS was weak (R 2 0.067, P < 0.001, AUC 0.605) at predicting 90 day mRS. A second model, including dynamic CTA variables (collateral grade, occlusion severity) showed better predictive accuracy for patient outcome (R 2 0.381, P < 0.001, AUC 0.781). A third model incorporating CTP variables showed very high predictive accuracy (R 2 0.488, P < 0.001, AUC 0.899). Combining all three imaging modalities variables also showed good predictive accuracy for outcome but did not improve on the CTP model (R 2 0.439, P < 0.001, AUC 0.825). CT perfusion predicts patient outcomes from alteplase therapy more accurately than models incorporating NCCT and/or CT angiography. This data has implications for artificial intelligence or machine learning models.

Exploring the relationship between ischemic core volume and clinical outcomes after thrombectomy or thrombolysis.

OBJECTIVE: To assess whether complete reperfusion after IV thrombolysis (IVT-R) would result in similar clinical outcomes compared to complete reperfusion after endovascular thrombectomy (EVT-R) in patients with a large vessel occlusion (LVO). METHODS: EVT-R patients were matched by age, clinical severity, occlusion location, and baseline perfusion lesion volume to IVT-R patients from the International Stroke Perfusion Imaging Registry (INSPIRE). Only patients with complete reperfusion on follow-up imaging were included. The excellent clinical outcome rates at day 90 on the modified Rankin Scale (mRS) were compared between EVT-R vs IVT-R patients within quintiles of increasing baseline ischemic core and penumbral volumes. RESULTS: From INSPIRE, there were 141 EVT-R patients and 141 matched controls (IVT-R) who met the eligibility criteria. In patients with a baseline core <30 mL, EVT-R resulted in a lower odds of achieving an excellent outcome at day 90 compared to IVT-R (day 90 mRS 0-1 odds ratio 0.01, p < 0.001). The group with a baseline core <30 mL contained mostly patients with distal M1 or M2 occlusions, and good collaterals (p = 0.01). In patients with a baseline ischemic core volume >30 mL (internal carotid artery and mostly proximal M1 occlusions), EVT-R increased the odds of patients achieving an excellent clinical outcome (day 90 mRS 0-1 odds ratio 1.61, p < 0.001) and there was increased symptomatic intracranial hemorrhage in the IVT-R group with core >30 mL (20% vs 3% in EVT-R, p = 0.008). CONCLUSION: From this observational cohort, LVO patients with larger baseline ischemic cores and proximal LVO, with poorer collaterals, clearly benefited from EVT-R compared to IVT-R alone. However, for distal LVO patients, with smaller ischemic cores and better collaterals, EVT-R was associated with a lower odds of favorable outcome compared to IVT-R alone.

The role of the basal ganglia in data processing.

Complex cerebral activities are likely to be composed of massively repeated simple data processing tasks since the cortical data processing unit, the cortical mini-column, is found throughout the cortex with only minor variations. It has been proposed that one task performed by the cortical mini-column may be to match afferent sensory data to learnt datasets in a process known as automatic association. We hypothesize that basal ganglia circuits, through the relative signal of the nigro-striatal and striato-pallidal pathways, determine the matching threshold for dataset matching within cortical mini-columns. Basal ganglia circuits are in a unique position to use parallel information to modulate the parameters of auto-association to increase the speed of data processing tasks. This hypothesis can explain motor symptoms in Parkinson's disease and also predicts that over and underactivity of basal ganglia circuits (the 'on' and 'off' states) will lead to characteristic errors in sensory data interpretation in all modalities - false negative data recognition when 'off' and false positive data recognition when 'on'. As a preliminary exploration of this hypothesis 16 patients with advanced Parkinson's disease were tested in voice and face recognition when 'off' and 'on'. Each patient exhibited errors in the recognition task according to basal ganglia activity as predicted by our hypothesis. Further experiments to test the hypothesis are proposed.

Cost-effectiveness of targeted thrombolytic therapy for stroke patients using multi-modal CT compared to usual practice.

INTRODUCTION: The use of multimodal computed tomography imaging (MMCT) in routine clinical assessment of stroke patients improves the identification of patients with large regions of salvageable brain tissue, lower risk for haemorrhagic transformation, or a large vessel occlusion requiring endovascular therapy. AIM: To evaluate the cost-effectiveness of using MMCT compared to usual practice for determining eligibility for reperfusion therapy with alteplase using real world data from the International Stroke Perfusion Imaging Registry (INSPIRE). METHODS: We performed a cost-utility analysis. Mean costs and quality-adjusted life years (QALYs) per patient for two alternative screening protocols were calculated. Protocol 1 represented usual practice, while Protocol 2 reflected treatment targeting using multimodal imaging. Cost-effectiveness was assessed using the net-benefit framework. RESULTS: Protocol 1 had a total mean per patient cost of $2,013 USD and 0.148 QALYs. Protocol 2 had a total mean per patient cost of $1,519 USD and 0.153 QALYs. For a range of willingness-to-pay values, representing implicit thresholds of cost-effectiveness, the lower bound of the incremental net monetary benefit statistic was consistently greater than zero, indicating that MMCT is cost- effective compared to usual practice. The results were most sensitive to variation in the mean number of alteplase vials administered. CONCLUSION: In a healthcare setting where multimodal imaging technologies are available and reimbursed, their use in screening patients presenting with acute stroke to determine eligibility for alteplase treatment is cost-effective given a range of willingness-to-pay thresholds and warrants consideration as an alternative to routine practice.

Stroke Epidemiology in an Australian Rural Cohort (SEARCH).

Background Stroke rates in Australia and New Zealand have been declining since 1990 but all studies have been completed in large urban centers. Aim We report the first Australasian stroke incidence study in a rural population. Methods The authors applied the principle of complete ascertainment, used the WHO standard definition of stroke and classified ischemic stroke by the TOAST criteria. Data were collected from five rural centers defined by postcode of residence, over a 2-year period with 12 months of follow up of all cases. Results There were 217 strokes in 215 individuals in a population of 96,036 people, over 2 years, giving a crude attack rate of 113 per 100,000 per year. The 181 first-ever strokes (83% of total), standardized to the WHO world population, occurred at a rate of 50/100,000 (95% CI: 43-58). The 28-day fatality for first-ever strokes was 24% (95% CI: 18-31) and 77% (95% CI: 71-83) were classified as ischemic (140/181), 15% (95% CI: 10-21) intracerebral hemorrhage, 3% (95% CI: 1-6) due to subarachnoid hemorrhage and 5% (95% CI: 2-9) were unknown. A high proportion of first-ever ischemic strokes (44%) were cardioembolic, mostly (77%) due to atrial arrhythmias. Of the 38 with known atrial arrhythmias prior to stroke, only six (16%) were therapeutically anticoagulated. Conclusions This rural companion study of a recent Australian urban stroke incidence study confirms the downward trend of stroke incidence in Australia, and reiterates that inadequate anticoagulation of atrial arrhythmia remains a preventable cause of ischemic stroke.

Global White Matter Hypoperfusion on CT Predicts Larger Infarcts and Hemorrhagic Transformation after Acute Ischemia.

INTRODUCTION: Presence of white matter hyperintensity (WMH) on MRI is a marker of cerebral small vessel disease and is associated with increased small vessel stroke and increased risk of hemorrhagic transformation (HT) after thrombolysis. AIM: We sought to determine whether white matter hypoperfusion (WMHP) on perfusion CT (CTP) was related to WMH, and if WMHP predisposed to acute lacunar stroke subtype and HT after thrombolysis. METHODS: Acute ischemic stroke patients within 12 h of symptom onset at 2 centers were prospectively recruited between 2011 and 2013 for the International Stroke Perfusion Imaging Registry. Participants routinely underwent baseline CT imaging, including CTP, and follow-up imaging with MRI at 24 h. RESULTS: Of 229 ischemic stroke patients, 108 were Caucasians and 121 Chinese. In the contralateral white matter, patients with acute lacunar stroke had lower cerebral blood flow (CBF) and cerebral blood volume (CBV), compared to those with other stroke subtypes (P = 0.041). There were 46 patients with HT, and WMHP was associated with increased risk of HT (R(2) = 0.417, P = 0.002). Compared to previously reported predictors of HT, WMHP performed better than infarct core volume (R(2) = 0.341, P = 0.034), very low CBV volume (R(2) = 0.249, P = 0.026), and severely delayed perfusion (Tmax>14 second R(2) = 0.372, P = 0.011). Patients with WMHP also had larger acute infarcts and increased infarct growth compared to those without WMHP (mean 28 mL vs. 13 mL P < 0.001). CONCLUSION: White matter hypoperfusion remote to the acutely ischemic region on CTP is a marker of small vessel disease and was associated with increased HT, larger acute infarct cores, and greater infarct growth.

STroke imAging pRevention and treatment (START): A longitudinal stroke cohort study: Clinical trials protocol.

RATIONALE: Stroke and poststroke depression are common and have a profound and ongoing impact on an individual's quality of life. However, reliable biological correlates of poststroke depression and functional outcome have not been well established in humans. AIMS: Our aim is to identify biological factors, molecular and imaging, associated with poststroke depression and recovery that may be used to guide more targeted interventions. DESIGN: In a longitudinal cohort study of 200 stroke survivors, the START-STroke imAging pRevention and Treatment cohort, we will examine the relationship between gene expression, regulator proteins, depression, and functional outcome. Stroke survivors will be investigated at baseline, 24 h, three-days, three-months, and 12 months poststroke for blood-based biological associates and at days 3-7, three-months, and 12 months for depression and functional outcomes. A sub-group (n = 100), the PrePARE: Prediction and Prevention to Achieve optimal Recovery Endpoints after stroke cohort, will also be investigated for functional and structural changes in putative depression-related brain networks and for additional cognition and activity participation outcomes. Stroke severity, diet, and lifestyle factors that may influence depression will be monitored. The impact of depression on stroke outcomes and participation in previous life activities will be quantified. STUDY OUTCOMES: Clinical significance lies in the identification of biological factors associated with functional outcome to guide prevention and inform personalized and targeted treatments. Evidence of associations between depression, gene expression and regulator proteins, functional and structural brain changes, lifestyle and functional outcome will provide new insights for mechanism-based models of poststroke depression.

A multicentre, randomized, double-blinded, placebo-controlled Phase III study to investigate EXtending the time for Thrombolysis in Emergency Neurological Deficits (EXTEND).

BACKGROUND AND HYPOTHESIS: Thrombolytic therapy with tissue plasminogen activator is effective for acute ischaemic stroke within 4·5 h of onset. Patients who wake up with stroke are generally ineligible for stroke thrombolysis. We hypothesized that ischaemic stroke patients with significant penumbral mismatch on either magnetic resonance imaging or computer tomography at three- (or 4·5 depending on local guidelines) to nine-hours from stroke onset, or patients with wake-up stroke within nine-hours from midpoint of sleep duration, would have improved clinical outcomes when given tissue plasminogen activator compared to placebo. STUDY DESIGN: EXtending the time for Thrombolysis in Emergency Neurological Deficits is an investigator-driven, Phase III, randomized, multicentre, double-blind, placebo-controlled study. Ischaemic stroke patients presenting after the three- or 4·5-h treatment window for tissue plasminogen activator and within nine-hours of stroke onset or with wake-up stroke within nine-hours from the midpoint of sleep duration, who fulfil clinical (National Institutes of Health Stroke Score ≥4-26 and prestroke modified Rankin Scale <2) will undergo magnetic resonance imaging or computer tomography. Patients who also meet imaging criteria (infarct core volume <70 ml, perfusion lesion : infarct core mismatch ratio >1·2, and absolute mismatch >10 ml) will be randomized to either tissue plasminogen activator or placebo. STUDY OUTCOME: The primary outcome measure will be modified Rankin Scale 0-1 at day 90. Clinical secondary outcomes include categorical shift in modified Rankin Scale at 90 days, reduction in the National Institutes of Health Stroke Score by 8 or more points or reaching 0-1 at day 90, recurrent stroke, or death. Imaging secondary outcomes will include symptomatic intracranial haemorrhage, reperfusion and or recanalization at 24 h and infarct growth at day 90.