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Thrombectomy in Extensive Stroke May Not Be Beneficial and Is Associated With Increased Risk for Hemorrhage

and for the German Stroke Registry–Endovascular Treatment (GSR-ET)
Originally published 2021;52:3109–3117


Background and Purpose:

This study evaluates the benefit of endovascular treatment (EVT) for patients with extensive baseline stroke compared with best medical treatment.


This retrospective, multicenter study compares EVT and best medical treatment for computed tomography (CT)–based selection of patients with extensive baseline infarcts (Alberta Stroke Program Early CT Score ≤5) attributed to anterior circulation stroke. Patients were selected from the German Stroke Registry and 3 tertiary stroke centers. Primary functional end points were rates of good (modified Rankin Scale score of ≤3) and very poor outcome (modified Rankin Scale score of ≥5) at 90 days. Secondary safety end point was the occurrence of symptomatic intracerebral hemorrhage. Angiographic outcome was evaluated with the modified Thrombolysis in Cerebral Infarction Scale.


After 1:1 pair matching, a total of 248 patients were compared by treatment arm. Good functional outcome was observed in 27.4% in the EVT group, and in 25% in the best medical treatment group (P=0.665). Advanced age (adjusted odds ratio, 1.08 [95% CI, 1.05–1.10], P<0.001) and symptomatic intracerebral hemorrhage (adjusted odds ratio, 6.35 [95% CI, 2.08–19.35], P<0.001) were independently associated with very poor outcome. Mortality (43.5% versus 28.9%, P=0.025) and symptomatic intracerebral hemorrhage (16.1% versus 5.6%, P=0.008) were significantly higher in the EVT group. The lowest rates of good functional outcome (≈15%) were observed in groups of failed and partial recanalization (modified Thrombolysis in Cerebral Infarction Scale score of 0/1–2a), whereas patients with complete recanalization (modified Thrombolysis in Cerebral Infarction Scale score of 3) with recanalization attempts ≤2 benefitted the most (modified Rankin Scale score of ≤3:42.3%, P=0.074) compared with best medical treatment.


In daily clinical practice, EVT for CT–based selected patients with low Alberta Stroke Program Early CT Score anterior circulation stroke may not be beneficial and is associated with increased risk for hemorrhage and mortality, especially in the elderly. However, first- or second-pass complete recanalization seems to reveal a clinical benefit of EVT highlighting the vulnerability of the low Alberta Stroke Program Early CT Score subgroup.


URL:; Unique identifier: NCT03356392.

See related article, p 3118

Currently, 4 randomized controlled trials (RCTs; TENSION [Efficacy and Safety of Thrombectomy in Stroke With Extended Lesion and Extended Time Window: A Randomized, Controlled Trial],1 TESLA [Thrombectomy for Emergent Salvage of Large Anterior Circulation Ischemic Stroke],2 IN EXTREMIS-LASTE [Large Stroke Therapy Evaluation],3 SELECT2 [A Randomized Controlled Trial to Optimize Patient’s Selection for Endovascular Treatment in Acute Ischemic Stroke]4) are ongoing to investigate the potential benefit of endovascular treatment (EVT) in patients with extensive signs of ischemic infarction on admission.5 Nevertheless, attributed to the lower expected effect size, higher sample sizes than in previous RCTs will be needed to prove a substantial treatment effect in this subgroup.6 Additionally, based on lower incidences of low Alberta Stroke Program Early CT Score (ASPECTS) patients, and depending on the physician’s opinion on clinical equipoise, a long enrollment period can be expected.7

In past thrombectomy landmark RCTs, patients presenting with ASPECTS ≤5 were assessed based on heterogeneous imaging protocols including both computed tomography (CT) and magnetic resonance imaging for treatment selection. In the HERMES (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials) meta-analysis, these patients were pooled and analyzed showing a nonsignificant trend towards a treatment benefit of EVT.8 Notwithstanding the latter, this effect seems not to be valid for CT-based patient selection (Figure I in the Data Supplement),9,10 although, CT imaging represents the most frequently applied real-world modality for detection and treatment of large vessel occlusion stroke.11 Hence, currently available randomized as well as retrospective evidence (Table 1)12–20 might not be representative for a real-world setting with CT-based decision-making for EVT in patients with low ASPECTS.9 Furthermore, it remains unclear if the overall treatment effect in patients with low ASPECTS will outweigh procedure-related risks in cases where EVT is unsuccessful.20

Table 1. Current Evidence of Endovascular Treatment for Stroke Patients With Low ASPECTS ≤5 in Nonrandomized Retrospective Studies With Regard to CT-Based Therapy Selection

Study (year)Study designSample size (N=)Medical control cohort (N=)CT-based treatment selection, % (N=)
Manceau et al12 (2018)SC82NoMRI only
Mourand et al13 (2018)SC10848MRI only
Kaesmacher et al14 (2019)MC237No33% (78/237)
Kakita et al15 (2019)MC50433210% (48/504)
Broocks et al16 (2019)MC11751100% (117/117)
Jiang et al17 (2019)MC8953Both
Deb-Chatterji et al18 (2019)MC152NoBoth
Panni et al19 (2019)MC216NoMRI only
Broocks et al20 (2020)SC17071100% (170/170)

ASPECTS indicates Alberta Stroke Program Early CT Scores; CT, computed tomography; MRI, magnetic resonance imaging; MS, multicenter; and SC, single-center.

This multicenter study compares outcomes between EVT and best medical treatment (BMT) cohorts in CT-based selection of stroke patients with low ASPECTS ≤5 in a real-world setting, that is, outside of randomized trials. We hypothesized that EVT is more beneficial than BMT in this subgroup.


The deidentified data analyzed in this study will be available and shared upon reasonable request from any qualified investigator for the purpose of replicating the results after clearance by the ethics and registry committee.

Study Cohort

All patients included in this study that received thrombectomy were enrolled in GSR-ET (German Stroke Registry—Endovascular Treatment) and treated between July 2015 and April 2018. The GSR-ET is an ongoing, open-label, prospective, multicenter registry of 25 sites in Germany collecting consecutive patients undergoing EVT. A detailed description21 and the major outcome findings of the GSR-ET study design have been published previously.22 For the comparison cohort three tertiary stroke centers (Medical Center Hamburg-Eppendorf, Germany; Hospital Bremen-Mitte, Bremen, Germany; National University Hospital Singapore, Singapore) were invited to contribute patients that underwent no EVT receiving BMT only. The main inclusion criteria for all cases were (1) CT-based diagnosis and treatment decision-making (2) of acute ischemic stroke due to anterior circulation vessel occlusions, (3) with ASPECTS 0 to 5 assessed on nonenhanced CT scans, (4) if treated endovascularly, thrombectomy was performed with approved devices, (5) if treated medically, patients with and without treatment of intravenous thrombolysis (IVT) were included based on local hospital protocols (Figure II in the Data Supplement provides a flow chart of patient inclusion criteria), (6) all patients were aged ≥18 years; there was no upper age limit. This study was prepared according to the Strengthening the Reporting of Observational Studies in Epidemiology statement (Table I in the Data Supplement).23

As the leading committee, the ethics committee of the Ludwig-Maximilians University (Munich) approved the GSR-ET. Additionally, local ethics committees of the participating hospitals gave approval as well.

Comparison of Treatment Groups

All patients that underwent EVT were compared with the BMT cohort with regard to functional outcomes and complications at 90-day follow-up. The primary functional outcomes were the rate of very poor outcome defined as a modified Rankin Scale (mRS) score of 5 to 6 and good functional outcome defined as mRS score of 0 to 3. The mRS was evaluated at 90-day follow-up by a physician or a trained and certified mRS nurse. As a subanalysis, primary functional outcomes of the EVT cohort were stratified by the degree of recanalization. Failed recanalization was defined as modified Thrombolysis in Cerebral Infarction Scale (mTICI) 0 and partial and incomplete recanalization as mTICI 1 to 2 and mTICI 2b, respectively. Accordingly, mTICI 2b was analyzed separately since its definition represents a wide range of recanalization degrees (51%–99%).11 Successful thrombectomy was defined as complete recanalization (mTICI 3). Additionally, outcome rates were subanalyzed by dichotomized subgroups of ASPECTS 0 to 3 and 4 to 5 as well as according to the number of thrombectomy maneuvers.

The secondary outcome with regard to safety was the rate of symptomatic intracranial hemorrhage (sICH) defined according to the second ECASS II (European-Australasian Acute Stroke Study) as presence of intracerebral hemorrhage and a 4-point neurological deterioration on the National Institutes of Health Stroke Scale (NIHSS).24

Statistical Analysis

Standard descriptive statistics were employed for all presented data. To reduce the possibility of selection bias, a propensity score matching (PSM) was performed to adjust for covariates of baseline and procedural variables. The propensity score was estimated using a logistic regression model adjusted for the following variables: age, sex, ASPECTS on admission, NIHSS on admission, and IVT. PSM was performed based on a 1:1 pair matching without replacement using the nearest-neighbor matching algorithm with a caliper width of 0.2. Before and after matching a graphical comparison was used to assess the distributional similarity between propensity score distributions (Figure III in the Data Supplement). Furthermore, a sensitivity analysis was performed, and each covariate was plotted against the estimated propensity score, stratified by treatment status (Figure IV in the Data Supplement).

After PSM, baseline characteristics and outcome variables were compared by using the χ2 tests for categorical variables, Mann-Whitney U test (non-normally distributed data), and the unpaired Student t test (normally distributed data) for continuous variables. Univariable and stepwise multivariable logistic regression analyses were performed for very poor outcome (mRS, 5–6) and mortality, as well as sICH and good outcome (mRS, 0–3) within the endovascular cohort. Results are presented as odds ratios (OR) with 95% CI. The significance level was set at α=0.05. Statistical analyses were carried out using SPSS Version 26 (SPSS, Chicago, IL) and R (R Core Team. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing. Vienna, Austria, 2017).


Baseline and Procedural Characteristics

Before PSM both cohorts showed significant differences in baseline characteristics (Table 2) of ASPECTS (median [interquartile range], EVT: 5 [4–5], BMT: 4 [2–4], P<0.001), and NIHSS (median [interquartile range], EVT: 18 [15–21], BMT: 19 [16–23], P=0.035). Procedural characteristics showed significant differences in the number of patients receiving IVT before EVT (EVT: 53.6% versus BMT: 76.5%, P<0.001).

Table 2. Patients’ Baseline, Procedural, and Outcome Characteristics Compared in Both Treatment Cohorts Before and After Propensity Score Matching

Baseline, procedural, and outcome characteristicsBefore propensity score matchingAfter propensity score matching
Endovascular treatment; N=168Best medical treatment; N=264P valuesEndovascular treatment; N=124Best medical treatment; N=124P values
Median age, y (IQR)73 (63–80)73 (61–81)0.70971 (59–78)73.5 (61–80)0.151
Female sex, n (%)69 (41.1)118 (44.7)0.39951 (41.1)56 (45.2)0.521
Median admission NIHSS (IQR)18 (15–21)19 (16–23)0.03517 (14–21)19 (15–22)0.140
Median admission ASPECTS (IQR)5 (4–5)4 (2–4)<0.001*4 (3–5)4 (3–5)0.754
Median time from onset to imaging (IQR)131 (67–194)112 (80.5–140)0.112131 (67–197)110 (78.5–139.5)0.179
IVT, n (%)90 (53.6)202 (76.5)<0.001*90 (72.6)86 (69.4)0.576
sICH, n (%)21 (12.5)21 (8)0.12020 (16.1)7 (5.6)0.008*
mTICI 2b/3, n (%)121 (72)92 (74.2)
Median mRS at 90 d (IQR)5 (3–6)5 (4–6)0.9545 (3–6)5 (3–6)0.266
 mRS score 0–3, n (%)46 (27.4)47 (18)0.39334 (27.4)31 (25)0.665
 mRS score 5–6, n (%)96 (57.1)160 (61.3)0.39172 (58.1)69 (55.6)0.701
 Mortality n (%)73 (43.5)91 (34.9)0.06954 (43.5)37 (29.8)0.025*

ASPECTS indicates Alberta Stroke Program Early CT Score; IQR, interquartile range; IVT, Intravenous Thrombolysis; mRS, modified Rankin Scale; mTICI, modified Thrombolysis in Cerebral Infarction Scale; NIHSS, National Institutes of Health Stroke Scale; and sICH, symptomatic intracerebral hemorrhage.

* Significant values.

† For 3 patients mRS at 90 days was not available.

After PSM, 124 stroke patients in each treatment arm were analyzed and compared. All occlusions were located within the anterior circulation which involved the M1 (MT: 68.6%, 85/124; BMT: 71.8%, 89/124) or M2 segment (MT: 7.2%, 9/124; BMT: 5.6%, 7/124) of the middle cerebral artery and the terminal carotid artery (MT: 24.2%, 30/124; BMT: 22.6%, 28/124). After PSM, patients’ baseline characteristics were balanced without any significant differences (Table 2).

Within the endovascular cohort recanalization degrees were distributed as followed: 10.5% (13/124) mTICI 0, 15.3% (19/124) mTICI 1 to 2a, 40.3% (50/124) mTICI 2b, 33.9% (42) mTICI 3. The median number of thrombectomy attempts was 2 (interquartile range, 1–4).

Functional Outcome and Complications

Good functional outcome was observed in 27.4% (34/124) and 25.0% (31/124) in the EVT and BMT group (P=0.665), respectively (Figure 1). Rates of mortality (43.5%, 54/124 versus 29.8%, 37/124, P=0.025) and sICH (16.1% versus 5.6%, P=0.008) were significantly higher in the EVT group, especially in the subgroup of ASPECTS 0 to 3 (21.2% [EVT] versus 2.9% [BMT]; P=0.025; Figure V in the Data Supplement). Rates of very poor outcome (mRS score of ≥5) did not differ significantly between both treatment groups (55.6%, 69/124 versus 58.1%, 72/124, P=0.701).

Figure 1.

Figure 1. Comparison of modified Rankin Scale (mRS) scores between both treatment cohorts stratified by recanalization degrees after propensity score matching. BMT indicates best MT; MT, medical treatment; mTICI, modified Thrombolysis in Cerebral Infarction Scale; and sICH, symptomatic intracerebral hemorrhage.

There was a tendency towards significantly less cases of sICH (7.1%, 3/42) in the subgroup of mTICI 3 compared with patients that did not receive complete reperfusion (26.2% 17/65, P=0.052).

In subanalysis stratified by recanalization degree, the group of failed (mTICI 0) and partial recanalization (mTICI 1–2a) showed nonsignificantly lower rates of good functional outcome of 15.4% (2/13, P=0.734) and 15.8% (3/19, P=0.564), respectively, compared with the BMT group. Rates of very poor outcome and mortality were significantly higher in the group of failed recanalization (mTICI 0) with rates of 84.6% (11/13, P=0.044) and 69.2% (9/13, P=0.004), respectively, compared with BMT. Within groups of incomplete (mTICI 2b) and complete recanalization (mTICI 3), good functional outcome was observed in 28% (14/50, P=0.683) and 35.7% (15/42, P=0.180), respectively. With regard to the number of recanalization attempts, the subgroup of mTICI 3 with a maximum of two thrombectomy attempts showed the highest rates of good functional outcome (42.3%, 11/26) at 90 days with a trend towards significance (P=0.074) compared to BMT. There were no significant differences in the functional outcome subanalysis dichotomized by subgroups of ASPECTS 0 to 3 and 4 to 5 (Figure VI in the Data Supplement).

Multivariable Logistic Regression Analysis

In multivariable logistic regression analysis (Table 3), higher age (adjusted OR [aOR], 1.08 [95% CI, 1.05–1.10], P<0.001), ASPECTS on admission (aOR, 0.72 [95% CI, 0.55–0.93], P=0.010), and sICH (aOR, 6.35 [95% CI, 2.08–19.35], P<0.001) were independent predictors for poor outcome (mRS score of 5–6) at 90 days in all patients. Furthermore, age (aOR, 1.07 [95% CI, 1.04–1.10], P<0.001), NIHSS on admission (aOR, 1.08 [95% CI, 1.03–1.13], P=0.002), sICH (aOR, 4.39 [95% CI, 1.69–11.38], P=0.002), and EVT (aOR, 2.2 [95% CI, 1.21–3.99], P=0.009) were independently associated with death at 90 days.

Table 3. Multivariable Logistic Regression Analysis for Independent Predictors of Very Poor Outcome (mRS Score of 5–6) and Mortality at 90-Day Follow-Up Within the Whole Study Population Regardless of Treatment Arm

CharacteristicsOR95% CIP value
Multivariable logistic regression analysis for very poor outcome
 Age, y1.081.05–1.10<0.001*
 Sex (male)0.919
 NIHSS on admission0.164
 ASPECTS on admission0.720.55–0.930.010*
Multivariable logistic regression analysis for mortality
 Age, y1.071.04–1.10<0.001*
 Sex (male)0.611
 NIHSS on admission1.081.03–1.130.002*
 ASPECTS on admission0.044

ASPECTS indicates Alberta Stroke Program Early CT Score; EVT, endovascular treatment; IVT, intravenous thrombolysis; mRS, modified Rankin Scale; NIHSS, National Institutes of Health Stroke Scale; OR, odds ratio; and sICH, symptomatic intracerebral hemorrhage.

* Significant values.

† Not selected in the last step of the regression model.

In the group of endovascularly treated patients, younger age (aOR, 0.93 [95% CI, 0.89–0.97] P<0.001), higher recanalization degrees (aOR, 1.45 [95% CI, 0.94–2.37] P=0.049), and cases without sICH (aOR, 0.14 [95% CI, 0.02–1.21], P=0.08) were independently associated with good outcome (mRS score of 0–3) at 90 days adjusted for covariates of sex, ASPECTS, NIHSS, and IVT (Figure 2).

Figure 2.

Figure 2. Forest plot based on stepwise multivariable regression analysis for independent predictors of good functional outcome (modified Rankin Scale [mRS] 0–3) at 90 d within the endovascular treatment after propensity score adjusted for covariates (sex, Alberta Stroke Program Early CT Scores, National Institutes of Health Stroke Scale, and intravenous thrombolysis). mTICI indicates modified Thrombolysis in Cerebral Infarction Scale; and sICH, symptomatic intracerebral hemorrhage.


Our retrospective multicenter study comparing cohorts of EVT and BMT in the setting of CT-based treatment selection for stroke patients presenting with low ASPECTS revealed several findings: (1) no general benefit of EVT over BMT was observed; (2) EVT led to significantly higher rates of sICH and mortality; (3) harmful effects of failed and partial recanalization following EVT may lead to higher rates of poor functional outcomes and mortality compared to BMT alone; (4) complete recanalization with a maximum of 2 thrombectomy attempts seems to reveal a substantial effect of EVT and thus, emphasizes technical success as a crucial mediator between benefit and harm in patients with low ASPECTS; (5) advanced age is strongly associated with poor outcomes and should be considered if intending EVT.

Given the increasing evidence that supports aggressive EVT across all subgroups, one should be aware that when treating subgroup patients outside of RCTs, complications leading to failed thrombectomy might result in harmful effects that could exceed overall treatment benefits,6 especially in daily clinical practice. Our study showed no general benefit of EVT over BMT alone in CT-based treatment decision-making for patients with low ASPECTS and was significantly associated with higher mortality. With regard to CT imaging, this finding is in line with the initial results of MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) showing no substantial benefit in the subgroup analysis of low ASPECTS patients.10 The second HERMES meta-analysis showed a promising trend towards treatment benefits of MT in patients with low ASPECTS; however, the sample size was underpowered to draw robust conclusions.8 This effect was possibly magnetic resonance imaging driven and on cases enrolled by the THRACE study (Mechanical Thrombectomy After Intravenous Alteplase Versus Alteplase Alone After Stroke). Interestingly, even the THRACE investigators did not observe a treatment effect in their initial subanalysis, whereby the question arises, how the HERMES subanalysis did show an effect (Figure I in the Data Supplement).8,25 However, no treatment effect for CT-selected cases was observed, although

HERMES core lab readers identified 34 more cases with low CT-ASPECTS.8 This highlights a fourfold problem: (1) substantial evidence of CT-selected and endovascularly treated low ASPECTS patients is currently sparse; (2) CT and magnetic resonance imaging–diffusion-weighted imaging have a poor intermodality agreement for ASPECTS reading26 and therefore, considerable differences in outcome prediction14; (3) the power of manual ASPECTS reading as a central treatment selection tool in patients with extensive baseline strokes on nonenhanced CT scans may be overestimated since the interrater agreement reliability is low and the clinical benefit of thrombectomy in low ASPECTS seems to be complexly mediated by individual factors such as preexisting diseases, age, infarct location, collaterals, and edema formation16,27–29; (4) CT-perfusion as an additional tool for treatment selection may lead to over-or underestimation of the early true infarct volume and remains a controversial modality in the light of the current debate on the infarct core concept.30–33

A post hoc analyses of the HERMES collaborators suggested that outcomes after EVT differed widely in the whole cohort when stratified by recanalization degree, even suggesting inferiority of failed recanalization compared with BMT. This was potentially attributed to procedure-related risks.34 Accordingly, we observed in a recent single-center low ASPECTS analysis that failed or incomplete recanalization did not result in worse outcomes compared to BMT.20 However, this might be explained by a previously reported single-center effect analyzing only cases from one tertiary stroke center with extensive experience in stroke care.35 On the contrary, the present study focused on large registry data also including cases from low-volume centers and observed a tendency towards inferiority in cases with failed and partial recanalization after EVT compared with BMT; however, the sample size in these subgroups was a priori underpowered to reach significance. Corroborating this finding, Kaesmacher et al14 observed in their subanalysis on CT-selected cases, only in 2 patients (2/24) a good functional outcome following unsuccessful recanalization (mTICI 0–2a). However, they reported good functional outcomes in up to 35% when thrombectomy was successful (mTICI 2b/3) in CT-selected cases. Similarly, we observed good functional outcomes in 36% of cases with mTICI 3 and even in 42% when complete recanalization was achieved with a maximum of two thrombectomy attempts. Although mortality rates were significantly higher in the EVT group, the proportions of patients with poor quality of life (mRS score of 5), which may be considered to be worse than death as a poststroke outcome, were reduced about 10% compared with the BMT group. Consequently, EVT might risk higher mortality for the sake of shifting some patients from mRS score of 5 to lower mRS scores, evoking an ethical debate about global functional outcome scales as primary study end points, with its focus on motor recovery, rather than subjective quality of life perception that immensely depends on societal and cultural differences.36,37

In comparison to HERMES meta-analysis,8 we found similar distributions of cases with sICH between both groups with significantly higher rates in the EVT cohort, especially in patients with ASPECTS 0 to 3 and a tendency towards lower incidences in completely recanalized cases as previously reported.14,38 This highlights the lack of pathophysiological understanding of cause and effect in sICH following EVT. Furthermore, multivariable logistic regression analysis revealed that the final mTICI score and the occurrence of sICH significantly impact good functional outcome. The aforementioned findings underscore the importance of technical success in EVT39,40 and reveal the vulnerability of stroke patients to potential procedure-related risks and complications, especially in low ASPECTS.8,41,42 Potential challenging interventions with high chances for failed recanalization (eg, due to vessel tortuosity) and postprocedural complications (eg, hospital-acquired infections) resulting in a poor outcome prognosis is a well-described phenomenon in EVT with an increased prevalence in very elderly patients.43,44 Accordingly, we found age independently associated with very poor outcome and mortality in both treatment arms. Thus, age as an individual baseline characteristic should be strongly considered when deciding to treat low ASPECTS patients endovascularly. Finally, the administration of bridging IVT in the setting of EVT is still a matter of current debate that is being investigated by ongoing RCTs, and this is even more controversial in patients with low ASPECTS as the evidence for IVT remains poor in this subgroup.45 Future results of stroke networks will hopefully provide further important insights into these subgroups at risk.46


Based on the absence of randomization and limited sample size, this study cannot be used to draw valid conclusions for decision-making in stroke patients with low ASPECTS. Despite using PSM to reduce the impact of potential confounding covariates, a possible selection bias cannot be ruled out due to the retrospective study design. Follow-up vessel imaging evaluating the post-treatment recanalization status was not performed in the BMT group and, therefore, was not available for further subgroup analysis and comparison.


Our study suggests no general benefit of EVT over BMT leading to high rates of mortality and sICH when treating CT-based selected patients with low ASPECTS in daily clinical practice. Failed and partial recanalization might be more harmful than BMT and thus, emphasizes the urgent need of the upcoming RCT results to define guidelines and recommendations for these critical stroke patients. Complete recanalization seems to be crucial for gaining a potential treatment benefit of EVT. Therefore, low ASPECTS patients might represent a subgroup at risk that should be treated in tertiary stroke centers with highly experienced neuro-interventionalists and neurological stroke care specialists; since these patients seem to be on the razor's edge between harm and benefit when treated endovascularly, this effect appears especially relevant in elderly patients.

Nonstandard Abbreviations and Acronyms


Alberta Stroke Program Early CT Score


best medical treatment


computed tomography


European-Australasian Acute Stroke Study


endovascular treatment


German Stroke Registry—Endovascular Treatment


intravenous thrombolysis


modified Rankin Scale


modified Thrombolysis in Cerebral Infarction Scale


National Institutes of Health Stroke Scale


symptomatic intracerebral hemorrhage

Supplemental Materials

Online Figures I–VI

Online Table I


GSR-ET Collaborators

Klinikum r.d.Isar, München (Silke Wunderlich, Tobias Boeckh-Behrens), Uniklinik RWTH Aachen (Arno Reich, Martin Wiesmann), Universitätsklinik Tübingen (Ulrike Ernemann, Till-Karsten Hauser), Charité – Campus Benjamin Franklin und Campus Charité Mitte, Berlin (Eberhard Siebert, Christian Nolte), Charité - Campus Virchow Klinikum, Berlin (Sarah Zweynert, Georg Bohner), Sana Klinikum Offenbach (Alexander Ludolph, Karl-Heinz Henn), Uniklinik Frankfurt/Main (Waltraud Pfeilschifter, Marlis Wagner), Asklepios Klinik Altona, Hamburg (Joachim Röther, Bernd Eckert), Klinikum Altenburger Land (Jörg Berrouschot, Albrecht Bormann), UKE Hamburg-Eppendorf (Anna Alegiani), Uniklinik Bonn (Elke Hattingen, Gabor Petzold), Klinikum Hanau (Sven Thonke, Christopher Bangard), Klinikum Lüneburg (Christoffer Kraemer), Uniklinik München (LMU) (Martin Dichgans, Frank Wollenweber, Lars Kellert, Franziska Dorn, Moriz Herzberg), Georg-August-Universität Göttingen (Marios Psychogios, Jan Liman), Klinikum Osnabrück (Martina Petersen, Florian Stögbauer), Uniklinik Würzburg (Peter Kraft, Mirko Pham), Bezirkskrankenhaus Günzburg (Michael Braun, Gerhard F. Hamann), Universitätsmedizin Mainz (Klaus Gröschel, Timo Uphaus), Kliniken Koeln (Volker Limmroth).

Disclosures Dr Fiehler reports research support from the German Ministry of Science and Education (BMBF), German Ministry of Economy and Innovation (BMWi), German Research Foundation (DFG), European Union (EU), Hamburgische Investitions-/Förderbank (IFB), Medtronic, Microvention, Philips, Stryker; consultancy appointments; Acandis, Bayer, Boehringer Ingelheim, Cerenovus, Covidien, Evasc Neurovascular, MD Clinicals, Medtronic, Medina, Microvention, Penumbra, Route92, Stryker, Transverse Medical; stock holdings for Tegus. Dr Thomalla reports receiving consulting fees from Acandis, grant support and lecture fees from Bayer, lecture fees from Boehringer Ingelheim, Bristol Myers Squibb/Pfizer, and Daiichi Sankyo, and consulting fees and lecture fees from Portola and Stryker. Dr Papanagiotou is a Consultant for Penumbra and Ab Medica. The other authors report no conflicts.


*A list of all German Stroke Registry–Endovascular Treatment (GSR-ET) members is given in the Appendix.

The Data Supplement is available with this article at

For Sources of Funding and Disclosures, see page 3115.

Correspondence to: Lukas Meyer, MD, Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Germany, Martinistrasse 52, 20246 Hamburg, Germany. Email


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