Sex differences in clot, vessel and tissue characteristics in patients with a large vessel occlusion treated with endovascular thrombectomy.

INTRODUCTION: To improve our understanding of the relatively poor outcome after endovascular treatment (EVT) in women we assessed possible sex differences in baseline neuroimaging characteristics of acute ischemic stroke patients with large anterior vessel occlusion (LVO). PATIENTS AND METHODS: We included all consecutive patients from the MR CLEAN Registry who underwent EVT between 2014 and 2017. On baseline non-contrast CT and CT angiography, we assessed clot location and clot burden score (CBS), vessel characteristics (presence of atherosclerosis, tortuosity, size, and collateral status), and tissue characteristics with the Alberta Stroke Program Early Computed Tomography Score (ASPECTS). Radiological outcome was assessed with the extended thrombolysis in cerebral infarction score (eTICI) and functional outcome with the modified Rankin Scale score (mRS) at 90 days. Sex-differences were assessed with multivariable regression analyses with adjustments for possible confounders. RESULTS: 3180 patients were included (median age 72 years, 48% women). Clots in women were less often located in the intracranial internal carotid artery (ICA) (25%vs 28%, odds ratio (OR) 0.85;95% confidence interval: 0.73-1.00). CBS was similar between sexes (median 6, IQR 4-8). Intracranial (aOR 0.73;95% CI:0.62-0.87) and extracranial (aOR 0.64;95% CI:0.43-0.95) atherosclerosis was less prevalent in women. Vessel tortuosity was more frequent in women in the cervical ICA (aOR 1.89;95% CI:1.39-2.57) and women more often had severe elongation of the aortic arch (aOR 1.38;95% CI:1.00-1.91). ICA radius was smaller in women (2.3vs 2.5 mm, mean difference 0.22;95% CI:0.09-0.35) while M1 radius was essentially equal (1.6vs 1.7 mm, mean difference 0.09;95% CI:-0.02-0.21). Women had better collateral status (⩾50% filling in 62%vs 53% in men, aOR 1.48;95% CI:1.29-1.70). Finally, ASPECT scores were equal between women and men (median 9 in both sexes, IQR 8-10vs 9-10). Reperfusion rates were similar between women and men (acOR 0.94;95% CI:0.83-1.07). However, women less often reached functional independence than men (34%vs 46%, aOR 0.68;95% CI:0.53-0.86). DISCUSSION AND CONCLUSION: On baseline imaging of this Dutch Registry, men and women with LVO mainly differ in vessel characteristics such as atherosclerotic burden, extracranial vessel tortuosity, and collateral status. These sex differences do not result in different reperfusion rates and are, therefore, not likely to explain the worse functional outcome in women after EVT.

Validity of Early Outcomes as Indicators for Comparing Hospitals on Quality of Stroke Care.

Background Insight into outcome variation between hospitals could help to improve quality of care. We aimed to assess the validity of early outcomes as quality indicators for acute ischemic stroke care for patients treated with endovascular therapy (EVT). Methods and Results We used data from the MR CLEAN (Multicenter Randomized Controlled Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) Registry, a large multicenter prospective cohort study including 3279 patients with acute ischemic stroke undergoing EVT. Random effect linear and proportional odds regression were used to analyze the effect of case mix on between-hospital differences in 2 early outcomes: the National Institutes of Health Stroke Scale (NIHSS) score at 24 to 48 hours and the expanded thrombolysis in cerebral infarction score. Between-hospital variation in outcomes was assessed using the variance of random hospital effects (tau2). In addition, we estimated the correlation between hospitals' EVT-patient volume and (case-mix-adjusted) outcomes. Both early outcomes and case-mix characteristics varied significantly across hospitals. Between-hospital variation in the expanded thrombolysis in cerebral infarction score was not influenced by case-mix adjustment (tau 2=0.17 in both models). In contrast, for the NIHSS score at 24 to 48 hours, case-mix adjustment led to a decrease in variation between hospitals (tau 2 decreases from 0.19 to 0.17). Hospitals' EVT-patient volume was strongly correlated with higher expanded thrombolysis in cerebral infarction scores (r=0.48) and weakly with lower NIHSS score at 24 to 48 hours (r=0.15). Conclusions Between-hospital variation in NIHSS score at 24 to 48 hours is significantly influenced by case-mix but not by patient volume. In contrast, between-hospital variation in expanded thrombolysis in cerebral infarction score is strongly influenced by EVT-patient volume but not by case-mix. Both outcomes may be suitable for comparing hospitals on quality of care, provided that adequate adjustment for case-mix is applied for NIHSS score.

Endovascular treatment versus no endovascular treatment after 6-24 h in patients with ischaemic stroke and collateral flow on CT angiography (MR CLEAN-LATE) in the Netherlands: a multicentre, open-label, blinded-endpoint, randomised, controlled, phase 3 trial.

BACKGROUND: Endovascular treatment for anterior circulation ischaemic stroke is effective and safe within a 6 h window. MR CLEAN-LATE aimed to assess efficacy and safety of endovascular treatment for patients treated in the late window (6-24 h from symptom onset or last seen well) selected on the basis of the presence of collateral flow on CT angiography (CTA). METHODS: MR CLEAN-LATE was a multicentre, open-label, blinded-endpoint, randomised, controlled, phase 3 trial done in 18 stroke intervention centres in the Netherlands. Patients aged 18 years or older with ischaemic stroke, presenting in the late window with an anterior circulation large-vessel occlusion and collateral flow on CTA, and a neurological deficit score of at least 2 on the National Institutes of Health Stroke Scale were included. Patients who were eligible for late-window endovascular treatment were treated according to national guidelines (based on clinical and perfusion imaging criteria derived from the DAWN and DEFUSE-3 trials) and excluded from MR CLEAN-LATE enrolment. Patients were randomly assigned (1:1) to receive endovascular treatment or no endovascular treatment (control), in addition to best medical treatment. Randomisation was web based, with block sizes ranging from eight to 20, and stratified by centre. The primary outcome was the modified Rankin Scale (mRS) score at 90 days after randomisation. Safety outcomes included all-cause mortality at 90 days after randomisation and symptomatic intracranial haemorrhage. All randomly assigned patients who provided deferred consent or died before consent could be obtained comprised the modified intention-to-treat population, in which the primary and safety outcomes were assessed. Analyses were adjusted for predefined confounders. Treatment effect was estimated with ordinal logistic regression and reported as an adjusted common odds ratio (OR) with a 95% CI. This trial was registered with the ISRCTN, ISRCTN19922220. FINDINGS: Between Feb 2, 2018, and Jan 27, 2022, 535 patients were randomly assigned, and 502 (94%) patients provided deferred consent or died before consent was obtained (255 in the endovascular treatment group and 247 in the control group; 261 [52%] females). The median mRS score at 90 days was lower in the endovascular treatment group than in the control group (3 [IQR 2-5] vs 4 [2-6]), and we observed a shift towards better outcomes on the mRS for the endovascular treatment group (adjusted common OR 1·67 [95% CI 1·20-2·32]). All-cause mortality did not differ significantly between groups (62 [24%] of 255 patients vs 74 [30%] of 247 patients; adjusted OR 0·72 [95% CI 0·44-1·18]). Symptomatic intracranial haemorrhage occurred more often in the endovascular treatment group than in the control group (17 [7%] vs four [2%]; adjusted OR 4·59 [95% CI 1·49-14·10]). INTERPRETATION: In this study, endovascular treatment was efficacious and safe for patients with ischaemic stroke caused by an anterior circulation large-vessel occlusion who presented 6-24 h from onset or last seen well, and who were selected on the basis of the presence of collateral flow on CTA. Selection of patients for endovascular treatment in the late window could be primarily based on the presence of collateral flow. FUNDING: Collaboration for New Treatments of Acute Stroke consortium, Dutch Heart Foundation, Stryker, Medtronic, Cerenovus, Top Sector Life Sciences & Health, and the Netherlands Brain Foundation.

Influence of the interventionist's experience on outcomes of endovascular thrombectomy in acute ischemic stroke: results from the MR CLEAN Registry.

BACKGROUND: The relationship between the interventionist's experience and outcomes of endovascular thrombectomy (EVT) for acute ischemic stroke of the anterior circulation, is unclear. OBJECTIVE: To assess the effect of the interventionist's level of experience on clinical, imaging, and workflow outcomes. Secondly, to determine which of the three experience definitions is most strongly associated with these outcome measures. METHODS: We analysed data from 2700 patients, included in the MR CLEAN Registry. We defined interventionist's experience as the number of procedures performed in the year preceding the intervention (EXPfreq), total number of procedures performed (EXPno), and years of experience (EXPyears). Our outcomes were the baseline-adjusted National Institutes of Health Stroke Scale (NIHSS) score at 24-48 hours post-EVT, recanalization (extended Thrombolysis in Cerebral Infarction (eTICI) score ≥2B), and procedural duration. We used multilevel regression models with interventionists as random intercept. For EXPfreq and EXPno results were expressed per 10 procedures. RESULTS: Increased EXPfreq was associated with lower 24-48 hour NIHSS scores (adjusted (a)ß:-0.46, 95% CI -0.70 to -0.21). EXPno and EXPyears were not associated with short-term neurological outcomes. Increased EXPfreq and EXPno were both associated with recanalization (aOR=1.20, 95% CI 1.11 to 1.31 and aOR=1.08, 95% CI 1.04 to 1.12, respectively), and increased EXPfreq, EXPno, and EXPyears were all associated with shorter procedure times (aß:-3.08, 95% CI-4.32 to -1.84; aß:-1.34, 95% CI-1.84 to -0.85; and aß:-0.79, 95% CI-1.45 to -0.13, respectively). CONCLUSIONS: Higher levels of interventionist's experience are associated with better outcomes after EVT, in particular when experience is defined as the number of patients treated in the preceding year. Every 20 procedures more per year is associated with approximately one NIHSS score point decrease, an increased probability for recanalization (aOR=1.44), and a 6-minute shorter procedure time.

Management of extracranial carotid artery stenosis during endovascular treatment for acute ischaemic stroke: results from the MR CLEAN Registry.

BACKGROUND: The optimal management of ipsilateral extracranial internal carotid artery (ICA) stenosis during endovascular treatment (EVT) is unclear. We compared the outcomes of two different strategies: EVT with vs without carotid artery stenting (CAS). METHODS: In this observational study, we included patients who had an acute ischaemic stroke undergoing EVT and a concomitant ipsilateral extracranial ICA stenosis of ≥50% or occlusion of presumed atherosclerotic origin, from the Dutch Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) Registry (2014-2017). The primary endpoint was a good functional outcome at 90 days, defined as a modified Rankin Scale score ≤2. Secondary endpoints were successful intracranial reperfusion, new clot in a different vascular territory, symptomatic intracranial haemorrhage, recurrent ischaemic stroke and any serious adverse event. RESULTS: Of the 433 included patients, 169 (39%) underwent EVT with CAS. In 123/168 (73%) patients, CAS was performed before intracranial thrombectomy. In 42/224 (19%) patients who underwent EVT without CAS, a deferred carotid endarterectomy or CAS was performed. EVT with and without CAS were associated with similar proportions of good functional outcome (47% vs 42%, respectively; adjusted OR (aOR), 0.90; 95% CI, 0.50 to 1.62). There were no major differences between the groups in any of the secondary endpoints, except for the increased odds of a new clot in a different vascular territory in the EVT with CAS group (aOR, 2.96; 95% CI, 1.07 to 8.21). CONCLUSIONS: Functional outcomes were comparable after EVT with and without CAS. CAS during EVT might be a feasible option to treat the extracranial ICA stenosis but randomised studies are warranted to prove non-inferiority or superiority.

Siamese model for collateral score prediction from computed tomography angiography images in acute ischemic stroke.

Introduction: Imaging biomarkers, such as the collateral score as determined from Computed Tomography Angiography (CTA) images, play a role in treatment decision making for acute stroke patients. In this manuscript, we present an end-to-end learning approach for automatic determination of a collateral score from a CTA image. Our aim was to investigate whether such end-to-end learning approaches can be used for this classification task, and whether the resulting classification can be used in existing outcome prediction models. Methods: The method consists of a preprocessing step, where the CTA image is aligned to an atlas and divided in the two hemispheres: the affected side and the healthy side. Subsequently, a VoxResNet based convolutional neural network is used to extract features at various resolutions from the input images. This is done by using a Siamese model, such that the classification is driven by the comparison between the affected and healthy using a unique set of features for both hemispheres. After masking the resulting features for both sides with the vascular region and global average pooling (per hemisphere) and concatenation of the resulting features, a fully connected layer is used to determine the categorized collateral score. Experiments: Several experiments have been performed to optimize the model hyperparameters and training procedure, and to validate the final model performance. The hyperparameter optimization and subsequent model training was done using CTA images from the MR CLEAN Registry, a Dutch multi-center multi-vendor registry of acute stroke patients that underwent endovascular treatment. A separate set of images, from the MR CLEAN Trial, served as an external validation set, where collateral scoring was assessed and compared with both human observers and a recent more traditional model. In addition, the automated collateral scores have been used in an existing functional outcome prediction model that uses both imaging and non-imaging clinical parameters. Conclusion: The results show that end-to-end learning of collateral scoring in CTA images is feasible, and does perform similar to more traditional methods, and the performance also is within the inter-observer variation. Furthermore, the results demonstrate that the end-to-end classification results also can be used in an existing functional outcome prediction model.

Association of thrombus density and endovascular treatment outcomes in patients with acute ischemic stroke due to M1 occlusions.

PURPOSE: We aimed to study the association of non-contrast CT (NCCT) thrombus density with procedural and clinical outcomes in patients with acute ischemic stroke who underwent endovascular treatment (EVT). Since thrombus density is associated with thrombus location, we focused on M1 occlusions only. METHODS: Patients with available thin-slice (< 2.5 mm) NCCT were included from a nationwide registry. Regression models were used to assess the relation between thrombus density (per Hounsfield unit [HU]) and the following outcomes. For reperfusion grade, adjusted common odds ratios (acOR) indicated a 1-step shift towards improved outcome per HU increase in thrombus density. For the binary outcomes of first-pass reperfusion (first-pass extended thrombolysis in cerebral infarction [eTICI] 2C-3, FPR), functional independence [90-day modified Rankin Scale (mRS) score of 0-2] and mortality), aORs were reported. Adjusted ß coefficients (aß) were reported for 24-h NIHSS and procedure duration in minutes. Outcome differences between first-line treatment devices (stent retriever versus aspiration) were assessed with interaction terms. RESULTS: In 566 patients with M1 occlusions, thrombus density was not associated with reperfusion (acOR 1.01, 95% CI 0.99-1.02), FPR (aOR 1.01, 95% CI 0.99-1.03), mortality (aOR 0.98, 95% CI 0.95-1.00), 24-h NIHSS (aß - 0.7%, 95% CI - 1.4-0.2), or procedure duration (aß 0.27, 95% CI - 0.05-0.58). In multivariable analysis, thrombus density was associated with functional independence (aOR 1.02, 95% CI 1.00-1.05). No interaction was found between thrombus density and first-line treatment device for any outcome. CONCLUSION: In patients with M1 occlusions, thrombus density was not clearly associated with procedural and clinical outcomes after EVT.

Safety and efficacy of aspirin, unfractionated heparin, both, or neither during endovascular stroke treatment (MR CLEAN-MED): an open-label, multicentre, randomised controlled trial.

BACKGROUND: Aspirin and unfractionated heparin are often used during endovascular stroke treatment to improve reperfusion and outcomes. However, the effects and risks of anti-thrombotics for this indication are unknown. We therefore aimed to assess the safety and efficacy of intravenous aspirin, unfractionated heparin, both, or neither started during endovascular treatment in patients with ischaemic stroke. METHODS: We did an open-label, multicentre, randomised controlled trial with a 2 × 3 factorial design in 15 centres in the Netherlands. We enrolled adult patients (ie, ≥18 years) with ischaemic stroke due to an intracranial large-vessel occlusion in the anterior circulation in whom endovascular treatment could be initiated within 6 h of symptom onset. Eligible patients had a score of 2 or more on the National Institutes of Health Stroke Scale, and a CT or MRI ruling out intracranial haemorrhage. Randomisation was done using a web-based procedure with permuted blocks and stratified by centre. Patients were randomly assigned (1:1) to receive either periprocedural intravenous aspirin (300 mg bolus) or no aspirin, and randomly assigned (1:1:1) to receive moderate-dose unfractionated heparin (5000 IU bolus followed by 1250 IU/h for 6 h), low-dose unfractionated heparin (5000 IU bolus followed by 500 IU/h for 6 h), or no unfractionated heparin. The primary outcome was the score on the modified Rankin Scale at 90 days. Symptomatic intracranial haemorrhage was the main safety outcome. Analyses were based on intention to treat, and treatment effects were expressed as odds ratios (ORs) or common ORs, with adjustment for baseline prognostic factors. This trial is registered with the International Standard Randomised Controlled Trial Number, ISRCTN76741621. FINDINGS: Between Jan 22, 2018, and Jan 27, 2021, we randomly assigned 663 patients; of whom, 628 (95%) provided deferred consent or died before consent could be asked and were included in the modified intention-to-treat population. On Feb 4, 2021, after unblinding and analysis of the data, the trial steering committee permanently stopped patient recruitment and the trial was stopped for safety concerns. The risk of symptomatic intracranial haemorrhage was higher in patients allocated to receive aspirin than in those not receiving aspirin (43 [14%] of 310 vs 23 [7%] of 318; adjusted OR 1·95 [95% CI 1·13-3·35]) as well as in patients allocated to receive unfractionated heparin than in those not receiving unfractionated heparin (44 [13%] of 332 vs 22 [7%] of 296; 1·98 [1·14-3·46]). Both aspirin (adjusted common OR 0·91 [95% CI 0·69-1·21]) and unfractionated heparin (0·81 [0·61-1·08]) led to a non-significant shift towards worse modified Rankin Scale scores. INTERPRETATION: Periprocedural intravenous aspirin and unfractionated heparin during endovascular stroke treatment are both associated with an increased risk of symptomatic intracranial haemorrhage without evidence for a beneficial effect on functional outcome. FUNDING: The Collaboration for New Treatments of Acute Stroke consortium, the Brain Foundation Netherlands, the Ministry of Economic Affairs, Stryker, Medtronic, Cerenovus, and the Dutch Heart Foundation.

Diagnostic performance of an algorithm for automated collateral scoring on computed tomography angiography.

OBJECTIVES: Outcome of endovascular treatment in acute ischemic stroke patients depends on collateral circulation to provide blood supply to the ischemic territory. We evaluated the performance of a commercially available algorithm for assessing the collateral score (CS) in acute ischemic stroke patients. METHODS: Retrospectively, baseline CTA scans (≤ 3-mm slice thickness) with an intracranial carotid artery (ICA), middle cerebral artery segment M1 or M2 occlusion, from the MR CLEAN Registry (n = 1627) were evaluated. All CTA scans were evaluated for visual CS (0-3) by eight expert radiologists (reference standard). A Web-based AI algorithm quantified the collateral circulation (0-100%) for correctly detected occlusion sides. Agreement between visual CS and categorized automated CS (0: 0%, 1: > 0- ≤ 50%, 2: > 50- < 100%, 3: 100%) was assessed. Area under the curve (AUC) values for classifying patients in having good (CS: 2-3) versus poor (CS: 0-1) collaterals and for predicting functional independence (90-day modified Rankin Scale 0-2) were computed. Influence of CTA acquisition timing after contrast material administration was reported. RESULTS: In the analyzed scans (n = 1024), 59% agreement was found between visual CS and automated CS. An AUC of 0.87 (95% CI: 0.85-0.90) was found for discriminating good versus poor CS. Timing of CTA acquisition did not influence discriminatory performance. AUC for predicting functional independence was 0.66 (95% CI 0.62-0.69) for automated CS, similar to visual CS 0.64 (95% CI 0.61-0.68). CONCLUSIONS: The automated CS performs similar to radiologists in determining a good versus poor collateral score and predicting functional independence in acute ischemic stroke patients with a large vessel occlusion. KEY POINTS: • Software for automated quantification of intracerebral collateral circulation on computed tomography angiography performs similar to expert radiologists in determining a good versus poor collateral score. • Software for automated quantification of intracerebral collateral circulation on computed tomography angiography performs similar to expert radiologists in predicting functional independence in acute ischemic stroke patients with a large vessel occlusion. • The timing of computed tomography angiography acquisition after contrast material administration did not influence the performance of automated quantification of the collateral status.

Improvements in Endovascular Treatment for Acute Ischemic Stroke: A Longitudinal Study in the MR CLEAN Registry.

BACKGROUND: We evaluated data from all patients in the Netherlands who underwent endovascular treatment for acute ischemic stroke in the past 3.5 years, to identify nationwide trends in time to treatment and procedural success, and assess their effect on clinical outcomes. METHODS: We included patients with proximal occlusions of the anterior circulation from the second and first cohorts of the MR CLEAN (Multicenter Randomized Clinical trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) Registry (March 2014 to June 2016; June 2016 to November 2017, respectively). We compared workflow times and rates of successful reperfusion (defined as an extended Thrombolysis in Cerebral Infarction score of 2B-3) between cohorts and chronological quartiles (all included patients stratified in chronological quartiles of intervention dates to create equally sized groups over the study period). Multivariable ordinal logistic regression was used to assess differences in the primary outcome (ordinal modified Rankin Scale at 90 days). RESULTS: Baseline characteristics were similar between cohorts (second cohort n=1692, first cohort n=1488) except for higher age, poorer collaterals, and less signs of early ischemia on computed tomography in the second cohort. Time from stroke onset to groin puncture and reperfusion were shorter in the second cohort (median 185 versus 210 minutes; P<0.001 and 236 versus 270 minutes; P<0.001, respectively). Successful reperfusion was achieved more often in the second than in the first cohort (72% versus 66%; P<0.001). Functional outcome significantly improved (adjusted common odds ratio 1.23 [95% CI, 1.07-1.40]). This effect was attenuated by adjustment for time from onset to reperfusion (adjusted common odds ratio, 1.12 [95% CI, 0.98-1.28]) and successful reperfusion (adjusted common odds ratio, 1.13 [95% CI, 0.99-1.30]). Outcomes were consistent in the analysis per chronological quartile. CONCLUSIONS: Clinical outcomes after endovascular treatment for acute ischemic stroke in routine clinical practice have improved over the past years, likely resulting from improved workflow times and higher successful reperfusion rates.

Complications of percutaneous transhepatic cholangiography and biliary drainage, a multicenter observational study.

OBJECTIVES: Over 2500 percutaneous transhepatic cholangiography and biliary drainage (PTCD) procedures are yearly performed in the Netherlands. Most interventions are performed for treatment of biliary obstruction following unsuccessful endoscopic biliary cannulation. Our aim was to evaluate complication rates and risk factors for complications in PTCD patients after failed ERCP. METHODS: We performed an observational study collecting data from a cohort that was subjected to PTCD during a 5-year period in one academic and four teaching hospitals. Primary objective was the development of infectious (sepsis, cholangitis, abscess, or cholecystitis) and non-infectious complications (bile leakage, severe hemorrhage, etc.) and mortality within 30 days of the procedure. Subsequently, risk factors for complications and mortality were analyzed with a multilevel logistic regression analysis. RESULTS: A total of 331 patients underwent PTCD of whom 205 (61.9%) developed PTCD-related complications. Of the 224 patients without a pre-existent infection, 91 (40.6%) developed infectious complications, i.e., cholangitis in 26.3%, sepsis in 24.6%, abscess formation in 2.7%, and cholecystitis in 1.3%. Non-infectious complications developed in 114 of 331 patients (34.4%). 30-day mortality was 17.2% (N = 57). Risk factors for infectious complications included internal drainage and drain obstruction, while multiple re-interventions were a risk factor for non-infectious complications. CONCLUSION: Both infectious and non-infectious complications are frequent after PTCD, most often due to biliary drain obstruction.

Malignant infarction after endovascular treatment: Incidence and prediction.

BACKGROUND: Early prediction of malignant infarction may guide treatment decisions. For patients who received endovascular treatment, the risk of malignant infarction is unknown and risk factors are unrevealed. AIMS: The objective of this study is to estimate the incidence of malignant infarction after endovascular treatment in patients with an occlusion of the anterior circulation, to identify independent risk factors, and to establish a model for prediction. METHODS: We analyzed patients who received endovascular treatment for a large vessel occlusion in the anterior circulation within 6.5 h after symptom onset, included in the Dutch MR CLEAN Registry between March 2014 and June 2016. We compared patients with and without malignant infarction. Candidate predictors were incorporated in a multivariable binary logistic regression model. The final prediction model was established using backward elimination. Discrimination and calibration were evaluated with the area under the receiver operating characteristic curve (AUROC) and the Hosmer-Lemeshow test. RESULTS: Of 1445 patients, 82 (6%) developed malignant infarction. Independent predictors were lower age, higher National Institutes of Health Stroke Scale (NIHSS), lower alberta stroke program early CT score (ASPECTS), internal carotid artery occlusion, lower collateral score, longer times from onset to groin puncture, and unsuccessful reperfusion. The AUROC of a prediction model combining these features was 0.83 (95% confidence interval (CI): 0.79-0.88) and the Hosmer-Lemeshow test indicated appropriate calibration (P = 0.937). CONCLUSION: The risk of malignant infarction after endovascular treatment started within 6.5 h of stroke onset is approximately 6%. Successful reperfusion decreases the risk. A prediction model combining easily retrievable measures of age, ASPECTS, collateral status, and reperfusion shows good discrimination between patients who will develop malignant infarction and those who will not.

Endovascular Thrombectomy in Young Patients With Stroke: A MR CLEAN Registry Study.

BACKGROUND AND PURPOSE: Acute ischemic stroke due to large vessel occlusion is uncommon in young adults. We assessed stroke cause in young patients and compared their outcomes after endovascular thrombectomy with older patients. METHODS: We used data (March 2014 until November 2017) of patients with an anterior circulation large vessel occlusion stroke from the MR CLEAN (Multicenter Randomized Controlled Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) Registry, a nationwide, prospective study on endovascular thrombectomy in the Netherlands. We compared young patients (18-49 years) with older patients (≥50 years). Outcomes included modified Rankin Scale score after 90 days (both shift and dichotomized analyses), expanded Thrombolysis in Cerebral Infarction score, and symptomatic intracranial hemorrhage. Analyses were adjusted for confounding. RESULTS: We included 3256 patients, 310 (10%) were 18 to 49 years old. Young patients had lower median National Institutes of Health Stroke Scale scores (14 versus 16, P<0.001) and less cardiovascular comorbidities than older patients. Stroke etiologies in young patients included carotid dissection (16%), cardio-embolism (15%), large artery atherosclerosis (10%), and embolic stroke of undetermined source (31%). Clinical outcome was better in young than older patients (acOR for modified Rankin Scale shift: 1.8 [95% CI, 1.5-2.2]; functional independence [modified Rankin Scale score 0-2] 61 versus 39% [adjusted odds ratio, 2.1 [95% CI, 1.6-2.8]); mortality 7% versus 32%, adjusted odds ratio, 0.2 [95% CI, 0.1-0.3]). Symptomatic intracranial hemorrhage occurred less frequently in young patients (3% versus 6%, adjusted odds ratio, 0.5 [95% CI, 0.2-1.00]). Successful reperfusion (expanded Thrombolysis in Cerebral Infarction Score 2b-3) did not differ between groups. Onset to reperfusion time was shorter in young patients (253 versus 255 minutes, adjusted B in minutes 12.4 [95% CI, 2.4-22.5]). CONCLUSIONS: Ten percent of patients with acute ischemic stroke undergoing endovascular thrombectomy were younger than 50. Cardioembolism and carotid dissection were common underlying causes in young patients. In one-third of cases, no cause was identified, indicating the need for more research on stroke cause in young patients. Young patients had better prognosis and lower risk of symptomatic intracranial hemorrhage than older patients.

Aspiration Versus Stent Retriever Thrombectomy for Posterior Circulation Stroke.

BACKGROUND AND PURPOSE: Whereas a clear benefit of endovascular treatment for anterior circulation stroke has been established, randomized trials assessing the posterior circulation have failed to show efficacy. Previous studies in anterior circulation stroke suggest that advanced thrombectomy devices were of great importance in achieving clinical benefit. Little is known about the effect of thrombectomy techniques on outcomes in posterior circulation stroke. In this study, we compare first-line strategy of direct aspiration to stent retriever thrombectomy for posterior circulation stroke. METHODS: We analyzed data of patients with a posterior circulation stroke who were included in the Multicentre Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands Registry between March 2014 and December 2018, a prospective, nationwide study, in which data were collected from consecutive patients who underwent endovascular treatment for ischemic stroke in the Netherlands. We compared patients who underwent first-line aspiration versus stent retriever thrombectomy. Primary outcome was functional outcome according to the modified Rankin Scale. Secondary outcomes were reperfusion grade, complication rate, and procedure duration. Associations between thrombectomy technique and outcome measures were estimated with multivariable ordinal logistic regression analyses. RESULTS: Overall, 71 of 205 patients (35%) were treated with aspiration, and 134 (65%) with stent retriever thrombectomy. Patients in the aspiration group had a lower pc-ASPECTS on baseline computed tomography, and general anesthesia was more often applied in this group. First-line aspiration was associated with better functional outcome compared with stent retriever thrombectomy (adjusted common odds ratio for a 1-point improvement on the modified Rankin Scale 1.94 [95% CI, 1.03-3.65]). Successful reperfusion (extended Thrombolysis in Cerebral Infarction ≥2B) was achieved more often with aspiration (87% versus 73%, P=0.03). Symptomatic hemorrhage rates were comparable (3% versus 4%). Procedure times were shorter in the aspiration group (49 versus 69 minutes P<0.001). CONCLUSIONS: In this retrospective nonrandomized cohort study, our findings suggest that first-line aspiration is associated with a shorter procedure time, better reperfusion, and better clinical outcome than stent retriever thrombectomy in patients with ischemic stroke based on large vessel occlusion in the posterior circulation.

Initial experience with dual-layer detector spectral CT for diagnosis of blood or contrast after endovascular treatment for ischemic stroke.

PURPOSE: To determine whether spectral detector CT (SDCT) with a plain non-enhanced monochromatic CT, a water-weighted image after iodine removal, an iodine map, and Mono energetic images changes the diagnosis and classification of intracranial hemorrhage based on single energy CT after endovascular treatment (EVT) for ischemic stroke. METHODS: Two readers evaluated single energy and SD CT data collected from 63 patients within one week after EVT. They diagnosed ICH or contrast staining, and graded ICH according to the Heidelberg and Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST) classification. Differences in diagnosis between single energy and SD CT were tested with Pearson's chi-squared test. Diagnostic values of single energy CT were calculated. Interrater agreement was based on Cohen's Kappa. RESULTS: When spectral data were added to single energy CT, the diagnosis of ICH changed in 8 CT scans (13%): in 4, the diagnosis of ICH was rejected and in 4, initially undetected ICH was diagnosed. In an additional 3 patients, the ICH grade was modified. CT alone had 88% sensitivity, 87% specificity, 88% positive diagnostic value, 87% negative diagnostic value, and 87% overall accuracy for ICH compared to SDCT. Interreader agreement on the presence of ICH was 0.84 (95% CI 0.51-0.86) for spectral CT and 0.84 (95% CI 0.73-0.97) for single energy CT. CONCLUSION: SD CT after endovascular treatment contributes to the distinction between intracranial hemorrhage and contrast staining.

A Randomized Trial of Intravenous Alteplase before Endovascular Treatment for Stroke.

BACKGROUND: The value of administering intravenous alteplase before endovascular treatment (EVT) for acute ischemic stroke has not been studied extensively, particularly in non-Asian populations. METHODS: We performed an open-label, multicenter, randomized trial in Europe involving patients with stroke who presented directly to a hospital that was capable of providing EVT and who were eligible for intravenous alteplase and EVT. Patients were randomly assigned in a 1:1 ratio to receive EVT alone or intravenous alteplase followed by EVT (the standard of care). The primary end point was functional outcome on the modified Rankin scale (range, 0 [no disability] to 6 [death]) at 90 days. We assessed the superiority of EVT alone over alteplase plus EVT, as well as noninferiority by a margin of 0.8 for the lower boundary of the 95% confidence interval for the odds ratio of the two trial groups. Death from any cause and symptomatic intracerebral hemorrhage were the main safety end points. RESULTS: The analysis included 539 patients. The median score on the modified Rankin scale at 90 days was 3 (interquartile range, 2 to 5) with EVT alone and 2 (interquartile range, 2 to 5) with alteplase plus EVT. The adjusted common odds ratio was 0.84 (95% confidence interval [CI], 0.62 to 1.15; P = 0.28), which showed neither superiority nor noninferiority of EVT alone. Mortality was 20.5% with EVT alone and 15.8% with alteplase plus EVT (adjusted odds ratio, 1.39; 95% CI, 0.84 to 2.30). Symptomatic intracerebral hemorrhage occurred in 5.9% and 5.3% of the patients in the respective groups (adjusted odds ratio, 1.30; 95% CI, 0.60 to 2.81). CONCLUSIONS: In a randomized trial involving European patients, EVT alone was neither superior nor noninferior to intravenous alteplase followed by EVT with regard to disability outcome at 90 days after stroke. The incidence of symptomatic intracerebral hemorrhage was similar in the two groups. (Funded by the Collaboration for New Treatments of Acute Stroke consortium and others; MR CLEAN-NO IV ISRCTN number, ISRCTN80619088.).

Importance of Occlusion Site for Thrombectomy Technique in Stroke: Comparison Between Aspiration and Stent Retriever.

BACKGROUND AND PURPOSE: Thrombectomy with stent retriever and direct aspiration are equally effective in the endovascular treatment of anterior circulation acute ischemic stroke. We report efficacy and safety of initial treatment technique per occlusion segment. METHODS: For this study, we analyzed data from the MR CLEAN Registry, a prospective, observational study in all centers that perform endovascular therapy in the Netherlands. We used ordinal logistic regression analysis to compare clinical and technical results of first line direct aspiration treatment with that of stent retriever thrombectomy stratified for occlusion segment. Primary outcome measure was functional outcome at 3 months. Secondary outcome measures included reperfusion grade expressed as the extended Thrombolysis in Cerebral Infarction score, periprocedural complication risk, time to reperfusion, and mortality. RESULTS: Of the 2282 included patients, 1658 (73%) were initially treated with stent retriever and 624 (27%) with aspiration. Four hundred sixty-two patients had an occlusion of the intracranial part of the carotid artery, 1349 of the proximal middle cerebral artery, and 471 of the distal parts of the middle cerebral artery. There was no difference in functional outcome between aspiration and stent retriever thrombectomy (odds ratio, 1.0 [95% CI, 0.9-1.2]) in any of the occlusion segments (P value for interaction=0.2). Reperfusion rate was higher in the aspiration group (odds ratio, 1.4 [95% CI, 1.1-1.6]) and did not differ between occlusion segments (P value for interaction=0.6). Procedure times were shorter in the aspiration group (minutes 50 versus 65 minutes; P<0.0001). There was no difference in periprocedural complications or mortality. CONCLUSIONS: In unselected patients with anterior circulation infarcts, we observed equal functional outcome of aspiration and stent retriever thrombectomy in all occlusion segments. When aspiration was the first line treatment modality, reperfusion rates were higher and procedure times shorter in all occlusion segments.

Embolization of the false lumen using IMPEDE-FX embolization plugs as part of treatment of an infrarenal post-dissection aneurysm: a case report.

BACKGROUND: This case report demonstrates the value of IMPEDE-FX plugs in an embolization procedure of a false lumen of an infrarenal post-dissection aneurysm. CASE PRESENTATION: A 69-year-old patient was treated with mitral valve replacement, complicated by a Stanford type-A dissection. After 9 years he presented with an enlarging infrarenal post-dissection aneurysm. The false lumen was embolized using multiple IMPEDE-FX plugs as part of the treatment in addition to embolization of the inferior mesenteric artery and overstenting of the re-entry in the right iliac artery. At 15 months the CTA showed a fully thrombosed false lumen and remodeling of the true lumen. CONCLUSIONS: The false lumen of an infrarenal post-dissection aneurysm can successfully be embolized using IMPEDE-FX embolization plugs as part of the treatment strategy. Prospective trials on patients with non-thrombosed false lumina are indicated.

Path From Clinical Research to Implementation: Endovascular Treatment of Ischemic Stroke in the Netherlands.

Before 2015, endovascular treatment (EVT) for acute ischemic stroke was considered a promising treatment option. Based on limited evidence, it was performed in several dedicated stroke centers worldwide on selected patients. Since 2015, EVT for patients with intracranial large vessel occlusion has quickly been implemented as standard treatment in many countries worldwide, supported by the revised international guidelines based on solid evidence from multiple clinical trials. We describe the development in use of EVT in the Netherlands before, during, and after the pivotal EVT trials. We used data from all patients who were treated with EVT in the Netherlands from January 2002 until December 2018. We undertook a time-series analysis to examine trends in the use of EVT using Poisson regression analysis. Incidence rate ratios per year with 95% CIs were obtained to demonstrate the impact and implementation after the publication of the EVT trial results. We made regional observation plots, adjusted for stroke incidence, to assess the availability and use of the treatment in the country. In the buildup to the MR CLEAN (Multicenter Clinical Trial of Endovascular Treatment of Acute Ischemic Stroke in the Netherlands), a slow increase of EVT patients was observed, with 0.2% of all ischemic stroke patients receiving EVT. Before the trial results were formally announced, a statistically significant increase in EVT-treated patients per year was observed (incidence rate ratio, 1.72 [95% CI, 1.46-2.04]), and after the trial publication, an immediate steep increase was seen, followed by a more gradual increase (incidence rate ratio, 2.14 [95% CI, 1.77-2.59]). In 2018, the percentage of ischemic stroke patients receiving EVT increased to 5.8%. A well-developed infrastructure, a pragmatic approach toward the use of EVT in clinical practice, in combination with a strict adherence by the regulatory authorities to national evidence-based guidelines has led to successful implementation of EVT in the Netherlands. Ongoing efforts are directed at further increasing the proportion of stroke patients with EVT in all regions of the country.

Anesthetic management during endovascular treatment of acute ischemic stroke in the MR CLEAN Registry.

OBJECTIVE: To compare outcomes after endovascular treatment (EVT) for acute ischemic stroke with 3 different types of anesthetic management in clinical practice, as anesthetic management may influence functional outcome. METHODS: Data of patients with an anterior circulation occlusion, included in the Dutch nationwide, prospective Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) Registry between March 2014 and June 2016, were analyzed. Patients were divided into 3 groups defined by anesthetic technique performed during EVT: local anesthesia only (LA), general anesthesia (GA), or conscious sedation (CS). Primary outcome was the modified Rankin Scale score at 90 days. To compare functional outcome between groups, we estimated a common odds ratio (OR) with ordinal logistic regression, adjusted for age, sex, prestroke modified Rankin Scale score, baseline NIH Stroke Scale score, collaterals, and time from onset to arrival at intervention center. RESULTS: A total of 1,376 patients were included. Performed anesthetic technique was LA in 821 (60%), GA in 381 (28%), and CS in 174 (13%) patients. Compared to LA, both GA and CS were associated with worse functional outcome on the modified Rankin Scale score at 90 days (GA cORadj 0.75; 95% confidence interval [CI] 0.58-0.97; CS cORadj 0.45; 95% CI 0.33-0.62). CS was associated with worse functional outcome than GA (cORadj 0.60; 95% CI 0.42-0.87). CONCLUSIONS: LA is associated with better functional outcome than systemic sedation in patients undergoing EVT for acute ischemic stroke. Whereas LA had a clear advantage over CS, this was less prominent compared to GA. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that for patients with acute ischemic stroke undergoing EVT, LA improves functional outcome compared to GA or CS.