Endovascular Thrombectomy Alone for Large Vessel Occlusion: A Cost-Effectiveness Evaluation Based on Meta-Analyses.

BACKGROUND: The benefit of intravenous thrombolysis with alteplase before endovascular thrombectomy (EVT) for acute ischemic stroke due to large vessel occlusion remains debated. In this study, we analyzed the cost-effectiveness of EVT alone versus intravenous alteplase before EVT in patients directly admitted to EVT-capable stroke centers from the Dutch health care payer perspective. METHODS: A decision analysis was performed using a Markov model with 15-year simulated follow-up to estimate total costs, quality-adjusted life years, and an incremental cost-effectiveness ratio of intravenous alteplase before EVT compared with EVT alone. A hypothetical cohort of 10 000 patients with large vessel occlusion aged 70 years was run in Monte Carlo simulation. Functional outcome of each treatment was derived from pooled results of 6 randomized controlled trials (RCTs). Uncertainty was assessed by probabilistic analyses, scenario analyses, and 1-way sensitivity analyses. RESULTS: Using functional outcomes obtained from 6 RCTs (intention-to-treat population), intravenous alteplase before EVT resulted in 0.05 quality-adjusted life years gained at an additional $2817 compared with EVT alone, resulting in the incremental cost-effectiveness ratio of $62 287. Probabilistic analyses showed that intravenous alteplase before EVT had a probability of 45% and 54%, respectively, of being cost-effective at the $52 500 and $84 000 thresholds. Restricting functional outcomes from our post hoc modified as-treated analysis of 6 RCTs (scenario 1), European RCTs (scenario 2), or a Dutch RCT (scenario 3), intravenous alteplase before EVT was cost-effective in 64%, 81%, and 50% of simulations at the $52 500 threshold, and 79%, 91%, and 67% of simulations at the $84 000 threshold. CONCLUSIONS: Intravenous alteplase before EVT was not cost-effective in patients with large vessel occlusion in the Netherlands at the $52 500 threshold but possibly cost-effective at the $84 000 threshold. Variable functional outcomes at 3 months based on different trial populations affected the cost-effectiveness of intravenous alteplase before EVT.

Left Atrial Appendage Opacification on Cardiac Computed Tomography in Acute Ischemic Stroke: The Clinical Implications of Slow-Flow.

BACKGROUND: Left atrial appendage (LAA) slow-flow may increase the risk of ischemic stroke. We studied LAA attenuation on cardiac computed tomography in patients with acute ischemic stroke. METHODS AND RESULTS: We used data from a prospective cohort of patients with acute ischemic stroke undergoing cardiac computed tomography during the acute stroke imaging protocol. We compared characteristics, functional outcome (modified Rankin scale: higher scores indicating worse outcome), stroke recurrence and major adverse cardiovascular events after 2-year follow-up between patients with LAA thrombus (filling defect<100 Hounsfield Unit (HU)), slow-flow (filling defect ≥100 HU) and normal filling. Of 421 patients, 31 (7%) had LAA thrombus, 69 (16%) slow-flow, and 321 (76%) normal filling. Patients with thrombus or slow-flow more often had known atrial fibrillation compared with normal filling (45%, 39%, and 9%, P<0.001). Patients with thrombus had higher National Institutes of Health Stroke Scale-scores compared with slow-flow and normal filling (18 [interquartile range, 9-22], 6 [interquartile range, 3-17], and 5 [interquartile range, 2-11], P<0.001). Compared with normal filling, there was no difference with slow-flow in functional outcome (median modified Rankin scale, 3 versus 2; acOR 0.8 [95% CI, 0.5-1.4]), stroke recurrence (adjusted hazard ratio, 0.8 [95% CI, 0.3-1.9]) or major adverse cardiovascular events (adjusted hazard ratio, 1.2 [95% CI, 0.7-2.1]), while patients with thrombus had worse functional outcome (median modified Rankin scale, 6, acOR, 3.3 [95% CI, 1.5-7.4]). In cryptogenic stroke patients (n=156) slow-flow was associated with stroke recurrence (27% versus 6%, aHR, 4.1 [95% CI, 1.1-15.7]). CONCLUSIONS: Patients with slow-flow had similar characteristics to patients with thrombus, but had less severe strokes. Slow-flow was not significantly associated with functional outcome or major adverse cardiovascular events, but was associated with recurrent stroke in patients with cryptogenic stroke.

HERMES-24 Score Derivation and Validation for Simple and Robust Outcome Prediction After Large Vessel Occlusion Treatment.

BACKGROUND: Clinicians need simple and highly predictive prognostic scores to assist practical decision-making. We aimed to develop a simple outcome prediction score applied 24 hours after anterior circulation acute ischemic stroke treatment with endovascular thrombectomy and validate it in patients treated both with and without endovascular thrombectomy. METHODS: Using the HERMES (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials) collaboration data set (n=1764), patients in the endovascular thrombectomy arm were divided randomly into a derivation cohort (n=430) and a validation cohort (n=441). From a set of candidate predictors, logistic regression modeling using forward variable selection was used to select a model that was both parsimonious and highly predictive for modified Rankin Scale (mRS) ≤2 at 90 days. The score was validated in validation cohort, control arm (n=893), and external validation cohorts from the ESCAPE-NA1 (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischaemic Stroke; n=1066) and INTERRSeCT (Identifying New Approaches to Optimize Thrombus Characterization for Predicting Early Recanalization and Reperfusion With IV Alteplase and Other Treatments Using Serial CT Angiography; n=614). RESULTS: In the derivation cohort, we selected 2 significant predictors of mRS ≤2 (National Institutes of Health Stroke Scale score at 24 hours and age [ß-coefficient, 0.34 and 0.06]) and derived the HERMES-24 score: age (years)/10+National Institutes of Health Stroke Scale score at 24 hours. The HERMES-24 score was highly predictive for mRS ≤2 (c-statistic 0.907 [95% CI, 0.879-0.935]) in the derivation cohort. In the validation cohort and the control arm, the HERMES-24 score predicts mRS ≤2 (c-statistic, 0.914 [95% CI, 0.886-0.944] and 0.909 [95% CI, 0.887-0.930]). Observed provability of mRS ≤2 ranged between 3.1% and 3.4% when HERMES-24 score ≥25, while it ranged between 90.6% and 93.0% when HERMES-24 score <10 in the derivation cohort, validation cohort, and control arm. The HERMES-24 score also showed c-statistics of 0.894 and 0.889 for mRS ≤2 in the ESCAPE-NA1 and INTERRSeCT populations. CONCLUSIONS: The post-treatment HERMES-24 score is a simple validated score that predicts a 3-month outcome after anterior circulation large vessel occlusion stroke regardless of intervention, which helps prognostic discussion with families on day 2.

Collateral-based selection for endovascular treatment of acute ischaemic stroke in the late window (MR CLEAN-LATE): 2-year follow-up of a phase 3, multicentre, open-label, randomised controlled trial in the Netherlands.

BACKGROUND: The MR CLEAN-LATE trial provided evidence for the safety and efficacy of endovascular treatment for acute ischaemic stroke within the late window (after 6-24 h) in patients who were preselected based on the presence of collateral flow on CT angiography. We aimed to evaluate clinical outcomes 2 years after randomisation. METHODS: MR CLEAN-LATE was a phase 3, multicentre, open-label, blinded-endpoint, randomised controlled trial conducted at 18 stroke intervention centres in the Netherlands. If endovascular treatment could be initiated within 6-24 h of symptom onset or last seen well, patients (aged 18 years or older) with an acute ischaemic stroke due to a large vessel occlusion in the anterior circulation and at least some collateral flow in the affected middle cerebral artery territory on CT angiography were randomly assigned (1:1) to either endovascular treatment with best medical treatment (endovascular treatment group) or best medical treatment alone (control group). Web-based randomisation, stratified by centre, was performed with the use of permuted blocks (block size eight to 20). The researchers who collected clinical outcomes and analysed the results were masked to treatment allocation; treating physicians, local investigators, and patients were aware of the received treatment. The primary outcome of MR CLEAN-LATE was the modified Rankin Scale (mRS) score at 90 days after randomisation. For this 2-year prespecified analysis, the primary outcome was mRS score at 2 years (minus 3 months to plus 6 months). Primary and safety analyses were performed based on the modified intention-to-treat principle, and included patients who provided (deferred) consent or died before consent could be obtained. Missing data were handled with multiple imputation by chained equations. The trial is completed and is registered at ISRCTN, ISRCTN19922220. FINDINGS: Between Feb 2, 2018, and Jan 27, 2022, 535 patients were randomly assigned in the MR CLEAN-LATE trial, of whom 502 (94%) gave deferred consent and comprised the modified intention-to-treat population (255 in the endovascular treatment group and 247 in the control group). 261 (52%) patients were female and 241 (48%) were male. Data for mRS score at 2 years were available for 226 (89%) patients in the endovascular treatment group and for 202 (82%) patients in the control group. The median mRS score at 2 years was 4 (IQR 2-6) in the endovascular treatment group and 6 (2-6) in the control group. The endovascular treatment group demonstrated a shift towards better functional outcomes on the mRS (adjusted common odds ratio 1·41 [95% CI 1·00-1·99]; p=0·049). All-cause mortality at 2 years was 34% (87 of 255) in the endovascular treatment group and 41% (101 of 247) in the control group (adjusted hazard ratio 0·81 [95% CI 0·60-1·08]; p=0·15). Major vascular events (ie, transient ischaemic attack, ischaemic stroke, haemorrhagic stroke, and cardiac events) were reported between 90 days and 2 years in 23 patients in the endovascular treatment group and 13 patients in the control group. INTERPRETATION: Our results show that the effectiveness of late-window (after 6-24 h) endovascular treatment in improving clinical outcomes is sustained for up to 2 years in a population preselected based on the presence of collateral flow on CT angiography. This finding might be important for prompting further evaluations of cost-effectiveness, health-care policy development, and clinical decision making. FUNDING: The Dutch Organization for Health Research and Health Innovation (ZonMW), Collaboration for New Treatments of Acute Stroke Consortium, Dutch Heart Foundation, Stryker, Medtronic, Cerenovus, Health Holland Top Sector Life Sciences & Health, and the Netherlands Brain Foundation.

Safety and efficacy of active blood-pressure reduction to the recommended thresholds for intravenous thrombolysis in patients with acute ischaemic stroke in the Netherlands (TRUTH): a prospective, observational, cluster-based, parallel-group study.

BACKGROUND: Intravenous thrombolysis is contraindicated in patients with ischaemic stroke with blood pressure higher than 185/110 mm Hg. Prevailing guidelines recommend to actively lower blood pressure with intravenous antihypertensive agents to allow for thrombolysis; however, there is no robust evidence for this strategy. Because rapid declines in blood pressure can also adversely affect clinical outcomes, several Dutch stroke centres use a conservative strategy that does not involve the reduction of blood pressure. We aimed to compare the clinical outcomes of both strategies. METHODS: Thrombolysis and Uncontrolled Hypertension (TRUTH) was a prospective, observational, cluster-based, parallel-group study conducted across 37 stroke centres in the Netherlands. Participating centres had to strictly adhere to an active blood-pressure-lowering strategy or to a non-lowering strategy. Eligible participants were adults (≥18 years) with ischaemic stroke who had blood pressure higher than 185/110 mm Hg but were otherwise eligible for intravenous thrombolysis. The primary outcome was functional status at 90 days, measured using the modified Rankin Scale and assessed through telephone interviews by trained research nurses. Secondary outcomes were symptomatic intracranial haemorrhage, the proportion of patients treated with intravenous thrombolysis, and door-to-needle time. All ordinal logistic regression analyses were adjusted for age, sex, stroke severity, endovascular thrombectomy, and baseline imbalances as fixed-effect variables and centre as a random-effect variable to account for the clustered design. Analyses were done according to the intention-to-treat principle, whereby all patients were analysed according to the treatment strategy of the participating centre at which they were treated. FINDINGS: Recruitment began on Jan 1, 2015, and was prematurely halted because of a declining inclusion rate and insufficient funding on Jan 5, 2022. Between these dates, we recruited 853 patients from 27 centres that followed an active blood-pressure-lowering strategy and 199 patients from ten centres that followed a non-lowering strategy. Baseline characteristics of participants from the two groups were similar. The 90-day mRS score was missing for 15 patients. The adjusted odds ratio (aOR) for a shift towards a worse 90-day functional outcome was 1·27 (95% CI 0·96-1·68) for active blood-pressure reduction compared with no active blood-pressure reduction. 798 (94%) of 853 patients in the active blood-pressure-lowering group were treated with intravenous thrombolysis, with a median door-to-needle time of 35 min (IQR 25-52), compared with 104 (52%) of 199 patients treated in the non-lowering group with a median time of 47 min (29-78). 42 (5%) of 852 patients in the active blood-pressure-lowering group had a symptomatic intracranial haemorrhage compared with six (3%) of 199 of those in the non-lowering group (aOR 1·28 [95% CI 0·62-2·62]). INTERPRETATION: Insufficient evidence was available to establish a difference between an active blood-pressure-lowering strategy-in which antihypertensive agents were administered to reduce blood pressure below 185/110 mm Hg-and a non-lowering strategy for the functional outcomes of patients with ischaemic stroke, despite higher intravenous thrombolysis rates and shorter door-to-needle times among those in the active blood-pressure-lowering group. Randomised controlled trials are needed to inform the use of an active blood-pressure-lowering strategy. FUNDING: Fonds NutsOhra.

Ultra-Early and Short-Term Tranexamic Acid Treatment in Patients With Good- and Poor-Grade Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND AND OBJECTIVES: The results of the ULTRA trial showed that ultra-early and short-term treatment with tranexamic acid (TXA) does not improve clinical outcome after aneurysmal subarachnoid hemorrhage (aSAH). Possibly, the lack of a beneficial effect in all patients with aSAH is masked by antagonistic effects of TXA in certain subgroups. In this post hoc subgroup analysis, we investigated the effect of TXA on clinical outcome in patients with good-grade and poor-grade aSAH. METHODS: The ULTRA trial was a multicenter, prospective, randomized, controlled, open-label trial with blinded outcome assessment. Participants received ultra-early and short-term TXA in addition to usual care or usual care only. This post hoc subgroup analysis included only ULTRA participants with confirmed aSAH and available World Federation of Neurosurgical Societies (WFNS) grade on admission. Patients were categorized into those with good-grade (WFNS 1-3) and poor-grade (WFNS 4-5) aSAH. The primary outcome was clinical outcome assessed by the modified Rankin scale (mRS). Odds ratios (ORs) and adjusted ORs (aORs) with 95% CIs were calculated using ordinal regression analyses. Analyses were performed using the as-treated principle. In all patients with aSAH, no significant effect modification of TXA on clinical outcome was observed for admission WFNS grade (p = 0.10). RESULTS: Of the 812 ULTRA participants, 473 patients had (58%; N = 232 TXA, N = 241 usual care) good-grade and 339 (42%; N = 162 TXA, N = 176 usual care) patients had poor-grade aSAH. In patients with good-grade aSAH, the TXA group had worse clinical outcomes (OR: 0.67, 95% CI 0.48-0.94, aOR 0.68, 95% CI 0.48-0.94) compared with the usual care group. In patients with poor-grade aSAH, clinical outcomes were comparable between treatment groups (OR: 1.04, 95% CI 0.70-1.55, aOR 1.05, 95% CI 0.70-1.56). DISCUSSION: This post hoc subgroup analysis provides another important argument against the use of TXA treatment in patients with aSAH, by showing worse clinical outcomes in patients with good-grade aSAH treated with TXA and no clinical benefit of TXA in patients with poor-grade aSAH, compared with patients treated with usual care. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov (NCT02684812; submission date February 18, 2016, first patient enrollment on July 24, 2013). CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that tranexamic acid, given for <24 hours within the first 24 hours, does not improve the 6-month outcome in good-grade or poor initial-grade aneurysmal SAH.

Long-Term Clinical Implications of High-Risk Cardiac Computed Tomography Findings in Patients With Acute Ischemic Stroke.

BACKGROUND: Cardiac computed tomography (CT) acquired during the initial acute stroke imaging protocol (acute cardiac CT) is increasingly used to screen for cardioembolism, but information on the long-term clinical implications of its findings is lacking. METHODS AND RESULTS: We performed a prospective, single-center cohort study in which consecutive patients with ischemic stroke underwent ECG-gated acute cardiac CT and were followed up for 2 years. The primary outcome was functional outcome assessed using the modified Rankin Scale. Secondary outcomes were death and occurrence of major adverse cardiovascular events (composite of recurrent ischemic stroke, myocardial infarction, and cardiovascular death). We compared patients with and without a high-risk structural source of embolism on acute cardiac CT. Of 452 included patients, 55 (12.2%) had a high-risk source of embolism, predominantly cardiac thrombi (38 patients) and signs of endocarditis (8 patients). Follow-up at 2 years was complete for 430 (95.1%) patients. Patients with a high-risk source of embolism had a worse functional outcome (median modified Rankin Scale, 6 [IQR, 2-6] versus 2 [IQR, 1-5]; adjusted common odds ratio, 2.92 [95% CI, 1.62-5.25]), increased mortality rate (52.7% versus 23.7%; adjusted hazard ratio [HR], 3.28 [95% CI, 1.94-5.52]), and major adverse cardiovascular events (38.9% versus 17.5%; adjusted HR, 3.20 [95% CI, 1.80-5.69]). A high-risk source of embolism was not associated with recurrent ischemic stroke (11.1% versus 9.6%; adjusted HR, 1.30 [95% CI, 0.49-3.44]). CONCLUSIONS: Structural high-risk sources of embolism on acute cardiac CT in patients with ischemic stroke were associated with poor long-term functional outcome and occurrence of major adverse cardiovascular events but not with recurrent stroke.

Thrombus Imaging Characteristics to Predict Early Recanalization in Anterior Circulation Large Vessel Occlusion Stroke.

The early management of transferred patients with a large vessel occlusion (LVO) stroke could be improved by identifying patients who are likely to recanalize early. We aim to predict early recanalization based on patient clinical and thrombus imaging characteristics. We included 81 transferred anterior-circulation LVO patients with an early recanalization, defined as the resolution of the LVO or the migration to a distal location not reachable with endovascular treatment upon repeated radiological imaging. We compared their clinical and imaging characteristics with all (322) transferred patients with a persistent LVO in the MR CLEAN Registry. We measured distance from carotid terminus to thrombus (DT), thrombus length, density, and perviousness on baseline CT images. We built logistic regression models to predict early recanalization. We validated the predictive ability by computing the median area-under-the-curve (AUC) of the receiver operating characteristics curve for 100 5-fold cross-validations. The administration of intravenous thrombolysis (IVT), longer transfer times, more distal occlusions, and shorter, pervious, less dense thrombi were characteristic of early recanalization. After backward elimination, IVT administration, DT and thrombus density remained in the multivariable model, with an AUC of 0.77 (IQR 0.72-0.83). Baseline thrombus imaging characteristics are valuable in predicting early recanalization and can potentially be used to optimize repeated imaging workflow.

Deep learning-based white matter lesion volume on CT is associated with outcome after acute ischemic stroke.

BACKGROUND: Intravenous thrombolysis (IVT) before endovascular treatment (EVT) for acute ischemic stroke might induce intracerebral hemorrhages which could negatively affect patient outcomes. Measuring white matter lesions size using deep learning (DL-WML) might help safely guide IVT administration. We aimed to develop, validate, and evaluate a DL-WML volume on CT compared to the Fazekas scale (WML-Faz) as a risk factor and IVT effect modifier in patients receiving EVT directly after IVT. METHODS: We developed a deep-learning model for WML segmentation on CT and validated with internal and external test sets. In a post hoc analysis of the MR CLEAN No-IV trial, we associated DL-WML volume and WML-Faz with symptomatic-intracerebral hemorrhage (sICH) and 90-day functional outcome according to the modified Rankin Scale (mRS). We used multiplicative interaction terms between WML measures and IVT administration to evaluate IVT treatment effect modification. Regression models were used to report unadjusted and adjusted common odds ratios (cOR/acOR). RESULTS: In total, 516 patients from the MR CLEAN No-IV trial (male/female, 291/225; age median, 71 [IQR, 62-79]) were analyzed. Both DL-WML volume and WML-Faz are associated with sICH (DL-WML volume acOR, 1.78 [95%CI, 1.17; 2.70]; WML-Faz acOR, 1.53 95%CI [1.02; 2.31]) and mRS (DL-WML volume acOR, 0.70 [95%CI, 0.55; 0.87], WML-Faz acOR, 0.73 [95%CI 0.60; 0.88]). Only in the unadjusted IVT effect modification analysis WML-Faz was associated with more sICH if IVT was given (p = 0.046). Neither WML measure was associated with worse mRS if IVT was given. CONCLUSION: DL-WML volume and WML-Faz had a similar relationship with functional outcome and sICH. Although more sICH might occur in patients with more severe WML-Faz receiving IVT, no worse functional outcome was observed. CLINICAL RELEVANCE STATEMENT: White matter lesion severity on baseline CT in acute ischemic stroke patients has a similar predictive value if measured with deep learning or the Fazekas scale. Safe administration of intravenous thrombolysis using white matter lesion severity should be further studied. KEY POINTS: White matter damage is a predisposing risk factor for intracranial hemorrhage in patients with acute ischemic stroke but remains difficult to measure on CT. White matter lesion volume on CT measured with deep learning had a similar association with symptomatic intracerebral hemorrhages and worse functional outcome as the Fazekas scale. A patient-level meta-analysis is required to study the benefit of white matter lesion severity-based selection for intravenous thrombolysis before endovascular treatment.

Advancements in diagnostic and interventional radiology for stroke treatment: the path from trial to bedside through the pre-MR CLEAN, MR CLEAN, and MR CLEAN II eras.

The stroke field is inevitably connected with imaging in which radiologists fulfill a central role. Our landmark MR CLEAN trial led to the implementation of baseline computed tomography angiography or magnetic resonance angiography in the acute stroke workup and subsequent endovascular treatment (EVT) for ischemic stroke patients with a large vessel occlusion in the anterior circulation, resulting in numerous patients worldwide currently being treated often successfully. A reversal of the pathophysiologic process behind an acute cerebrovascular event was made possible. Subsequently, in the MR CLEAN II trials, the clinical impact of both diagnostic and interventional radiologists remained a cornerstone of our research, which means value-based radiology. Within these MR CLEAN II trials, we proved that aspirin and heparin during EVT should be avoided due to increased symptomatic intracranial hemorrhage risk (MR CLEAN-MED). We concluded there is additional benefit of EVT in the 6-to-24-h window after stroke in the presence of good collaterals on baseline CTA (MR CLEAN-LATE). The impactful success of our stroke trials that changed many guidelines was mainly attributable to (1) the societal burden of the disease, with two thirds of patients dying or being independent at 3 months; (2) the fact that stroke is a common disease, (3) the relatively simple and pragmatic approach of the trials resembling real-world setting; (4) the acceleration of implementation in clinical practice facilitated by a structured approach to guideline development and conditional funding; and foremost (5) the excellent collaboration on a professional level between-disciplines, i.e., diagnostic radiologists, interventionalists, and neurologists.Critical relevance statement The MR CLEAN and MR CLEAN II trials have had tremendous impact on clinical practice, directly by more patients being treated with an effective intervention and indirectly through adoption of evidence-based guidelines. It is in this setting of stroke treatment that diagnostic and interventional radiologists have played a crucial role and created clinical impact.