Cerebral Small Vessel Disease and Infarct Growth in Acute Ischemic Stroke Treated with Intravenous Thrombolysis.

We investigated relations between cerebral small vessel disease (cSVD) markers and evolution of the ischemic tissue from ischemic core to final infarct in people with acute ischemic stroke treated with intravenous thrombolysis. Data from the Stroke Imaging Repository (STIR) and Virtual International Stroke Trials Archive (VISTA) were used. Any pre-existing lacunar infarcts and white matter hyperintensities (WMH) were assessed on magnetic resonance (MR) before thrombolytic therapy. Acute ischemic core and final infarct volume were then assessed by two independent radiologists. The relationship among baseline markers of cSVD, acute ischemic core volume, final infarct volume, infarct growth (IG = final infarct - ischemic core), and infarct growth ratio (IGR = final infarct/ischemic core) was then assessed using linear and ordinal regression adjusted for age, sex, onset-to-treatment time, and stroke severity. We included 165 patients, mean (± SD) age 69.5 (± 15.7) years, 74 (45%) males, mean (± SD) ischemic core volume 25.48 (± 42.22) ml, final infarct volume 52.06 (± 72.88) ml, IG 26.58 (± 51.02) ml, IGR 8.23 (± 38.12). Seventy (42%) patients had large vessel occlusion, 20 (12%) acute small subcortical infarct. WMHs were present in 131 (79%) and lacunar infarcts in 61 (37%) patients. Final infarct volumes were 53.8 ml and 45.2 ml (WMHs/no WMHs), p = 0.139, and 24.6 ml and 25.9 ml (lacunar infarcts/no lacunar infarcts), p = 0.842. In linear and ordinal regression analyses, presence of lacunar infarcts was associated with smaller IG (ß = - 0.17; p = 0.024; cOR = 0.52; 95%CI = 0.28-0.96, respectively) and WMHs were associated with smaller IGR (ß = - 0.30; p = 0.004; cOR = 0.27; 95%CI = 0.11-0.69, respectively). In people with acute ischemic stroke treated with intravenous thrombolysis, cSVD features were associated with smaller growth of the acute ischemic area, suggesting less salvageable tissue at time of reperfusion therapy.

Xanthine oxidase inhibition and white matter hyperintensity progression following ischaemic stroke and transient ischaemic attack (XILO-FIST): a multicentre, double-blinded, randomised, placebo-controlled trial.

Background: People who experience an ischaemic stroke are at risk of recurrent vascular events, progression of cerebrovascular disease, and cognitive decline. We assessed whether allopurinol, a xanthine oxidase inhibitor, reduced white matter hyperintensity (WMH) progression and blood pressure (BP) following ischaemic stroke or transient ischaemic attack (TIA). Methods: In this multicentre, prospective, randomised, double-blinded, placebo-controlled trial conducted in 22 stroke units in the United Kingdom, we randomly assigned participants within 30-days of ischaemic stroke or TIA to receive oral allopurinol 300 mg twice daily or placebo for 104 weeks. All participants had brain MRI performed at baseline and week 104 and ambulatory blood pressure monitoring at baseline, week 4 and week 104. The primary outcome was the WMH Rotterdam Progression Score (RPS) at week 104. Analyses were by intention to treat. Participants who received at least one dose of allopurinol or placebo were included in the safety analysis. This trial is registered with ClinicalTrials.gov, NCT02122718. Findings: Between 25th May 2015 and the 29th November 2018, 464 participants were enrolled (232 per group). A total of 372 (189 with placebo and 183 with allopurinol) attended for week 104 MRI and were included in analysis of the primary outcome. The RPS at week 104 was 1.3 (SD 1.8) with allopurinol and 1.5 (SD 1.9) with placebo (between group difference -0.17, 95% CI -0.52 to 0.17, p = 0.33). Serious adverse events were reported in 73 (32%) participants with allopurinol and in 64 (28%) with placebo. There was one potentially treatment related death in the allopurinol group. Interpretation: Allopurinol use did not reduce WMH progression in people with recent ischaemic stroke or TIA and is unlikely to reduce the risk of stroke in unselected people. Funding: The British Heart Foundation and the UK Stroke Association.

Safety and Outcomes of Thrombectomy in Ischemic Stroke With vs Without IV Thrombolysis.

OBJECTIVE: To test the hypothesis that IV thrombolysis (IVT) treatment before endovascular thrombectomy (EVT) is associated with better outcomes in patients with anterior circulation large artery occlusion (LAO) stroke, we examined a large real-world database, the Safe Implementation of Treatment in Stroke-International Stroke Thrombectomy Register (SITS-ISTR). METHODS: We identified centers recording ≥10 consecutive patients in the SITS-ISTR, with at least 70% available modified Rankin Scale (mRS) scores at 3 months during 2014 to 2019. We defined LAO as intracranial internal carotid artery, first and second segment of middle cerebral artery, and first segment of anterior cerebral artery. Main outcomes were functional independence (mRS score 0-2) and death at 3 months and symptomatic intracranial hemorrhage (SICH) per modified SITS-Monitoring Study. We performed propensity score-matched (PSM) and multivariable logistic regression analyses. RESULTS: Of 6,350 patients from 42 centers, 3,944 (62.1%) received IVT. IVT + EVT-treated patients had less frequent atrial fibrillation, ongoing anticoagulation, previous stroke, heart failure, and prestroke disability. PSM analysis showed that IVT + EVT-treated patients had a higher rate of functional independence than patients treated with EVT alone (46.4% vs 40.3%, p < 0.001) and a lower rate of death at 3 months (20.3% vs 23.3%, p = 0.035). SICH rates (3.5% vs 3.0%, p = 0.42) were similar in both groups. Multivariate adjustment yielded results consistent with PSM. CONCLUSION: Pretreatment with IVT was associated with favorable outcomes in EVT-treated LAO stroke in the SITS-ISTR. These findings, while indicative of international routine clinical practice, are limited by observational design, unmeasured confounding, and possible residual confounding by indication. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that IVT before EVT increases the probability of functional independence at 3 months compared to EVT alone.

The SITS Open Study: A Prospective, Open Label Blinded Evaluation Study of Thrombectomy in Clinical Practice.

BACKGROUND AND PURPOSE: We designed SITS (Safe Implementation of Treatment in Stroke) Open to determine benefit and safety of thrombectomy in clinical practice for large artery occlusion stroke, using selected stent retrievers plus standard care versus standard care alone. METHODS: SITS Open was a prospective, open, blinded evaluation, international, multicenter, controlled, nonrandomized registry study. Centers lacking access to thrombectomy contributed controls. Primary end point was categorical shift in modified Rankin Scale score at 3 months in the per protocol (PP) population. Principal secondary outcomes were symptomatic intracranial hemorrhage, functional independency (modified Rankin Scale score 0-2) and death at 3 months. Patients independently evaluated by video-recorded modified Rankin Scale interviews blinded to treatment or center identity by central core laboratory were regarded as PP population. Propensity score matching with covariate adjusted analysis was performed. RESULTS: During 2014 to 2017, 293 patients (257 thrombectomy, 36 control) from 26 centers in 10 countries fulfilled intention-to-treat and 200 (170 thrombectomy, 30 control) PP criteria; enrollment of controls was limited by rapid uptake of thrombectomy. In PP analysis, median age was 71 versus 71 years, and baseline National Institutes of Health Stroke Scale 17 versus 17 in the thrombectomy and control arms, respectively. The propensity score matching analysis for PP showed a significant shift for modified Rankin Scale at 3 months favoring the thrombectomy group (odds ratio, 3.8 [95% CI, 1.61-8.95]; P=0.002). Regarding safety, there were 4 cases of symptomatic intracranial hemorrhage in the thrombectomy group (2.4%) and none in the control group. CONCLUSIONS: In clinical practice, thrombectomy for patients with large artery occlusion stroke is superior to standard of care in our study. Registration: URL: https://www.clinicaltrials.gov. Unique Identifier: NCT02326428.

Accurate prediction of clinical stroke scales and improved biomarkers of motor impairment from robotic measurements.

OBJECTIVE: One of the greatest challenges in clinical trial design is dealing with the subjectivity and variability introduced by human raters when measuring clinical end-points. We hypothesized that robotic measures that capture the kinematics of human movements collected longitudinally in patients after stroke would bear a significant relationship to the ordinal clinical scales and potentially lead to the development of more sensitive motor biomarkers that could improve the efficiency and cost of clinical trials. MATERIALS AND METHODS: We used clinical scales and a robotic assay to measure arm movement in 208 patients 7, 14, 21, 30 and 90 days after acute ischemic stroke at two separate clinical sites. The robots are low impedance and low friction interactive devices that precisely measure speed, position and force, so that even a hemiparetic patient can generate a complete measurement profile. These profiles were used to develop predictive models of the clinical assessments employing a combination of artificial ant colonies and neural network ensembles. RESULTS: The resulting models replicated commonly used clinical scales to a cross-validated R2 of 0.73, 0.75, 0.63 and 0.60 for the Fugl-Meyer, Motor Power, NIH stroke and modified Rankin scales, respectively. Moreover, when suitably scaled and combined, the robotic measures demonstrated a significant increase in effect size from day 7 to 90 over historical data (1.47 versus 0.67). DISCUSSION AND CONCLUSION: These results suggest that it is possible to derive surrogate biomarkers that can significantly reduce the sample size required to power future stroke clinical trials.

The Incidence and Associated Factors of Early Neurological Deterioration After Thrombolysis: Results From SITS Registry.

BACKGROUND AND PURPOSE: Early neurological deterioration (END) after stroke onset may predict severe outcomes. Estimated rates of END after intravenous thrombolysis among small patient samples have been reported up to 29.8%. We studied the incidence and factors associated with END among patients following intravenous thrombolysis. METHODS: We analyzed SITS-International Stroke Thrombolysis registry patients with known outcomes enrolled in 2010 to 2017. END was defined as an increase in National Institutes of Health Stroke Scale score ≥4 or death within 24 hours from baseline National Institutes of Health Stroke Scale. We determined the incidence of END and used logistic regression models to inspect its associated factors. We adjusted for variables found significant in univariate analyses (P<0.05). Main outcomes were incidence of END, associated predictors of END, ordinal day-90 mRS, and day-90 mortality. RESULTS: We excluded 53 539 patients and included 50 726 patients. The incidence of END was 3415/50 726 (6.7% [95% CI, 6.5%-7.0%]). Factors independently associated with END on multivariate analysis were intracerebral hemorrhage (OR, 3.23 [95% CI, 2.96-3.54], P<0.001), large vessel disease (LVD) with carotid stenosis (OR, 2.97 [95% CI, 2.45-3.61], P<0.001), other LVD (OR, 2.41 [95% CI, 2.03-2.88], P<0.001), and ischemic stroke versus transient ischemic attack (TIA)/stroke mimics (OR, 16.14 [95% CI, 3.99-65.3], P<0.001). END was associated with worse outcome on ordinal mRS: adjusted OR 2.48 (95% CI, 2.39-2.57, P<0.001) by day-90 compared with no END. The adjusted OR for day-90 mortality was 9.70 (95% CI, 8.36-11.26, P<0.001). CONCLUSIONS: The routinely observed rate of END reflected by real-world data is low, but END greatly increases risk of disability and mortality. Readily identifiable factors predict END and may help with understanding causal mechanisms to assist prevention of END.

Alteplase for Acute Ischemic Stroke in Patients Aged >80 Years: Pooled Analyses of Individual Patient Data.

BACKGROUND/PURPOSE: Expert guidelines specify no upper age limit for alteplase for thrombolysis of acute ischemic stroke (AIS) but, until recently, European regulatory criteria restricted its use to patients aged 18 to 80 years. We performed pooled analyses of randomized controlled trial (RCT) and registry data to evaluate the benefit-risk profile of alteplase for AIS among patients aged >80 years to support a regulatory application to lift the upper age restriction. METHODS: Individual patient data were evaluated from 7 randomized trials of alteplase (0.9 mg/kg) versus placebo or open control for AIS, and the European SITS-UTMOST registry database. Clinical outcomes, including good functional outcome (score 0-1, modified Rankin Scale day 90 or Oxford Handicap Score day 180), were evaluated in the full RCT and registry populations, and specified age-based subgroups (≤80 or >80 years) who met existing European regulatory criteria for alteplase, excluding upper age restriction. RESULTS: Regardless of treatment allocation, 90-day mortality was lower among RCT patients aged ≤80 versus >80 years who otherwise met existing European regulatory criteria (246/2405 [10.2%] versus 307/1028 [29.9%], respectively). Among patients aged >80 years, alteplase versus placebo was associated with a higher proportion of good stroke outcome (modified Rankin Scale score 0-1; 99/518 [19.1%] versus 67/510 [13.1%]; P=0.0109) and similar 90-day mortality (153/518 [29.5%] versus 154/510 [30.2%]; P=0.8382). The odds of a good stroke outcome following alteplase allocation in the full RCT population were independent of age (P=0.7383). Good stroke outcome was reported for almost half (4821/11 169 [43.2%]) of the patients who received alteplase in routine practice. Outcomes in routine practice supported those achieved in RCTs. CONCLUSIONS: Alteplase for AIS has a positive benefit-risk profile among patients aged >80 years when administered according to other regulatory criteria. Alteplase for AIS should be evaluated on an individual benefit-risk basis.

Missing outcome data management in acute stroke trials testing iv thrombolytics. Is there risk of bias?

INTRODUCTION: Missing outcome data may undermine interpretation of randomised clinical trials by weakening power and limiting apparent effect size. We assessed bias and inefficiency of two imputation methods commonly used in stroke trials evaluating the efficacy of iv thrombolysis. PATIENTS AND METHODS: We searched the virtual international stroke trials archive (VISTA)-acute for ischaemic stroke patients with 90-day modified Rankin scale as an outcome, and known thrombolysis status. We excluded any with missing 30-day modified Rankin scale. We planned two analyses; first, we calculated odds ratios for outcome in thrombolysed versus not thrombolysed from imputed-only data, (a) among patients with missing modified Rankin scale 90 and (b) among matched patients with intact data (using propensity score methods and relevant covariates). Imputation approaches were last observation carried forward (LOCF) or multiple imputation. Outcome comparisons used dichotomisation and shift analysis. Thereafter, we calculated whole-population odds ratios using LOCF and multiple imputation (also through dichotomisation and shift analysis); first with the original 1.5% missing outcome data, and then artificially increasing the burden (5%; 10%; 20%; 30%). RESULTS: We considered 9657 patients from eight of the studies included in VISTA, 3034 (31%) thrombolysed. Missing data replacement by LOCF with analysis by dichotomisation gave the highest estimate of thrombolysis influence. Imputing while increasing the burden of missing data progressively raised the odds ratios estimates, though thresholds for overestimation were 10% for LOCF; 20% for multiple imputation.Discussion: Replacing missing outcome data tended to overestimate differences of thrombolysed versus non-thrombolysed patients, but had minimal impact below a 10% burden of missing data.Conclusion: In the specific context of acute stroke trials testing iv thrombolytics, replacing missing data by carrying forward the last observation tended to overestimate treatment odds ratios more than multiple imputation.

The impact of atrial fibrillation type on the risks of thromboembolic recurrence, mortality and major haemorrhage in patients with previous stroke: A systematic review and meta-analysis of observational studies.

INTRODUCTION: There is conflicting evidence on the impact of atrial fibrillation (AF) type, i.e. non-paroxysmal AF or paroxysmal AF, on thromboembolic recurrence. The consensus of risk equivalence is greatly based on historical evidence, focussing on initial stroke risks. We conducted a systematic review and meta-analysis to describe the impact of AF type on the risk of thromboembolic recurrence, mortality and major haemorrhage in patients with previous stroke. METHODS: We systematically searched four multidisciplinary databases from inception to December 2018. We selected observational studies investigating clinical outcomes in patients with ischaemic stroke and AF, stratified by AF type. We assessed all included studies for risk of bias using the 'Risk of Bias In Non-randomised Studies - of Exposures' tool. The Comprehensive Meta-Analysis Software was used to calculate odds ratios from crude event rates. RESULTS: After reviewing 14,127 citations, we selected 108 studies for full-text screening. We extracted data from a total of 26 studies, reporting outcomes on 23,054 patients. Overall, risk of bias was moderate. The annual incidence rates of thromboembolism in patients with non-paroxysmal AF and paroxysmal AF were 7.1% (95% confidence interval: 4.2-11.7) and 5.2% (95% confidence interval: 3.2-8.2), respectively. The odds ratio for thromboembolism in patients with non-paroxysmal AF versus paroxysmal AF was 1.47 (95% confidence interval: 1.08-1.99, p = 0.013). The annual mortality rates in patients with non-paroxysmal AF and paroxysmal AF were 20.0% (95% confidence interval: 13.2-28.0) and 10.1% (95% confidence interval: 5.4-17.3), respectively, and odds ratio was 1.90 (95% confidence interval: 1.43-2.52, p < 0.001). There was no difference in rates of major haemorrhage, odds ratio = 1.01 (95% confidence interval: 0.61-1.69, p = 0.966). CONCLUSION: In patients with prior stroke, non-paroxysmal AF is associated with significantly higher risk of thromboembolic recurrence and mortality than paroxysmal AF. Although current guidelines make no distinction between non-paroxysmal AF and paroxysmal AF for secondary stroke prevention, future guidance and risk stratification tools may need to consider this differential risk (PROSPERO ID: CRD42019118531).