Endovascular thrombectomy for acute ischaemic stroke with established large infarct (TENSION): 12-month outcomes of a multicentre, open-label, randomised trial

Summary Background Long-term data showing the benefits of endovascular thrombectomy for stroke with large infarct are scarce. The TENSION trial showed the safety and efficacy of endovascular thrombectomy in patients with ischaemic stroke and large infarct at 90 days. We aimed to investigate the safety and efficacy at 12 months of endovascular thrombectomy in patients who were enrolled in the TENSION trial


Introduction
Endovascular thrombectomy in patients with acute ischaemic stroke due to large vessel occlusion improves functional outcome compared with medical treatment alone and has become the standard of care.[4][5]6 Available long-term data from endovascular thrombectomy trials, which mostly included patients with small or medium-sized infarcts, suggest that the beneficial effect of treatment on functional outcome at 90 days-the usual timepoint for primary endpoints in stroke reperfusion trials-persists in long-term followup. 7,8This observation from earlier trials was reproduced in 1-year follow-up data from the SELECT2 trial 9 of thrombectomy in patients with extensive ischaemic changes on CT or perfusion imaging, and in 6-month follow-up data from the LASTE trial 6 of thrombectomy for stroke with large infarct of unrestricted size.
3][4][5] Individual patients might have delayed recovery with better outcomes at 1 year, but long-term rates of death and dependence also show a further increase in patients with severe stroke. 10urther more, little is known about individual trajectories of outcome following thrombectomy for large infarct.
TENSION (The Efficacy and Safety of Thrombectomy in Stroke with extended lesion and extended time window) was a randomised controlled trial of thrombectomy up to 12 h after symptom onset or last seen well for patients with a large infarct, defined as an Alberta Stroke Protocol Early CT Score (ASPECTS) of 3-5 due to a large vessel occlusion identified by visual assessment of standard-of-care stroke imaging, reflecting clinical practice.The objective of this prespecified analysis of the TENSION trial was to investigate the effect of endovascular thrombectomy on functional outcome, self-reported quality of life, poststroke depression, and overall survival at 12 months after stroke.

Study design and participants
TENSION was an investigator-initiated, open-label, blinded endpoint, randomised trial done at 40 hospitals across Europe and one hospital in Canada. 2 The trial was designed to enrol patients with acute ischaemic stroke with large vessel occlusion and already-extended infarct as assessed by standard-of-care imaging used in the participating hospitals.A full list of inclusion and exclusion criteria is provided in the trial protocol and with the main trial publication. 2,11In summary, patients

Research in context
Evidence before this study We searched PubMed on April 15, 2024, for randomised trials of endovascular thrombectomy versus medical treatment in adults with acute ischaemic stroke and large vessel occlusion presenting with already-extended infarct using the search terms "randomised trial" OR "randomized trial" AND "thrombectomy" AND "large core" OR "large infarct" OR "low ASPECTS".We found four trials: the RESCUE-Japan LIMIT trial with 203 patients in Japan; the ANGEL-ASPECT trial with 456 patients in China; the international SELECT2 trial with 352 patients; and the TENSION trial with 253 patients in Europe and Canada.All four trials reported better functional outcome at 90 days with endovascular thrombectomy compared with medical management alone.SELECT2 reported sustained benefit of thrombectomy on functional outcome at 1-year follow-up.For the other trials, long-term follow-up results were not available.By contrast with RESCUE-Japan LIMIT, ANGEL-ASPECT, and SELECT2, in which patient enrolment was either entirely or mostly based on MRI or perfusion CT involving commercial software for post-processing, TENSION used non-contrast CT as the predominant imaging modality.Two further trials (TESLA and LASTE) have published their protocols, but at the time of our search had not yet published their primary findings.

Added value of this study
TENSION was the first clinical trial of endovascular thrombectomy based on standard-of-care stroke imaging without the need for perfusion imaging for patient enrolment, meaning that the results can easily be transferred to clinical practice in most interventional stroke centres worldwide.These findings further extend the results of SELECT2 by showing a benefit of thrombectomy over medical treatment with various patient-reported outcomes at 12 months and by a sustained improvement in overall survival.

Implications of all the available evidence
In the TENSION trial, endovascular thrombectomy was associated with improved functional outcome, overall survival, and quality of life at 12 months in patients with large vessel occlusions of the anterior circulation presenting with a large infarct within 12 h of symptom onset or last known well.These results confirm the sustained benefit of endovascular thrombectomy on functional outcome, as shown in the 1-year follow-up results from SELECT2, and support the use of endovascular thrombectomy for these patients, guided by non-contrast CT, MRI, or perfusion imaging.
were eligible if they presented with acute ischaemic stroke due to an occlusion in the M1 segment of the middle cerebral artery or the intracranial segment of the distal internal carotid artery on CT angiography or magnetic resonance angiography, and an ASPECTS of 3-5 on unenhanced CT or diffusion-weighted imaging, as assessed locally.Patients were randomly assigned within 11 h after symptom onset or last seen well, with expected completion of endovascular thrombectomy within 12 h.Eligible patients were aged 18 years or older, had a maximum National Institutes of Health Stroke Scale (NIHSS) score below 26 (with scores ranging from 0 to 42 and higher scores indicating worse neurological deficits), and were premorbidly independent, which was defined as an estimated prestroke score of 0-2 on the modified Rankin Scale (mRS; scores range from 0 to 6, with 0 indicating no disability, 1 no clinically significant disability, 2 slight disability, 3 moderate disability but able to walk unassisted, 4 moderately severe disability, 5 severe disability, and 6 death).Imaging exclusion criteria were known vascular disease preventing endovascular thrombectomy or high-grade extracranial stenosis expected to require acute stent placement, and any acute intracranial bleeding or mass effect.Informed consent from patients or legal representatives was obtained before enrolment in the trial.
The trial protocol and all amendments are available together with the publication of the main trial results. 2 The protocol was approved by the institutional review board of the University of Heidelberg (Heidelberg, Germany; ref S-248/2016) and all participating hospitals before the start of patient enrolment.The trial was monitored by an independent data and safety monitoring board.This trial is registered at ClinicalTrials.gov,NCT03094715.

Randomisation and masking
Patients were randomly assigned to undergo endovascular thrombectomy in addition to medical treatment or medical treatment only (1:1) using a central web-based module, with a permuted block design (random block sizes of two and four).Randomisation was stratified by time from symptom onset or last known well (<6 h and 6-11 h) and stroke severity (NIHSS ≤18 and NIHSS 19-25) to assure balance within these key prognostic variables.All follow-up examinations were done by investigators or trial personnel masked to the patients' group assignment.

Procedures
Endovascular thrombectomy was done according to local standards using stent retrievers, aspiration devices, or both, with or without balloon guide catheter.The choice of the devices used for thrombectomy, anaesthesia, intra-procedure management, and post-procedure management was left to the discretion of the treating doctor.Best medical treatment was performed according to national and international guidelines in both groups, including intravenous thrombolysis, if indicated. 9,10ll patients underwent a standardised imaging protocol at baseline, which included either unenhanced CT supplemented by CT angiography in hospitals where CT was used as the first-line diagnostic modality for acute stroke, or MRI with diffusion-weighted imaging and magnetic resonance angiography in hospitals where MRI was used as the first-line diagnostic modality for acute stroke, according to institutional standards.ASPECTS for trial inclusion was rated at the respective site on unenhanced images from CT or diffusion-weighted imaging.Before site initiation, all investigators completed web-based ASPECTS training. 6All imaging data were transferred to a central core lab (Eppdata, Hamburg, Germany) and assessed masked to group assignment by expert readers following a standardised workflow.
The clinical assessment was done at baseline, at 24 h (±6 h), at 7 days or at hospital discharge, at 90 days (±14 days), and after 12 months (±14 days).Disease characteristics assessed at baseline included estimation of pre-stroke functional status using the mRS, presenting symptoms, and stroke severity according to NIHSS score.Follow-up assessments at 90 days (±14 days) and after 12 months (±14 days) additionally included: patientreported outcome measures of health-related quality of life, which were assessed by the EQ-5D and the Patient-Reported Outcomes Measurement Information System 10-item (PROMIS-10) questionnaires; and post-stroke anxiety and depression, which were assessed by the Patient Health Questionnaire-4 (PHQ-4).All examinations were done by trained and certified investigators masked to the patients' group assignment.At 90 days and 12 months, if an in-person assessment was not possible, a telephone interview was done to assess the mRS score.The mRS score at 12 months was assessed

Outcomes
The primary endpoint of the TENSION trial was a difference across the entire range of the mRS score at 90 days (±14 days) between groups in ordinal analysis (shift analysis). 2In this Article, we report prespecified analyses of 12-month (±14 days) outcomes of the trial, comprising functional outcome across the entire range of the mRS score, assessed by smRSq; functional health status and QoL, assessed by EQ-5D and PROMIS-10; post-stroke anxiety and depression, assessed with PHQ-4; and overall survival.Additional post-hoc outcomes were independent outcome (mRS score ≤2), being able to walk alone unaided (mRS score ≤3), and death or dependency (mRS score 4-6).

Statistical analysis
The analysis followed the statistical analysis plan, which was finalised before database lock for the analysis of the primary endpoint.The trial was stopped early after the boundaries for efficacy were crossed at the first interim analysis in February, 2023, when 222 patients had reached the primary outcome.Follow-up was continued for all 253 patients who had been randomly assigned up to that point and constituted the final analysis population.
As with the analysis of the primary endpoint of the trial, all analyses of efficacy outcomes at 12 months were done in the intention-to-treat population, with patients classified on the basis of the treatment group to which they were randomly assigned, regardless of the treatment received and regardless of protocol violations.For the functional outcome across the entire range of the mRS score, the analysis was repeated in the per-protocol population as a sensitivity analysis.Safety analyses were done according to treatment received.Here, the endovascular thrombectomy group included all patients in whom endovascular thrombectomy was initiated and groin puncture was at least attempted, including patients receiving endovascular thrombectomy outside the trial protocol, and the medical treatment group included all patients in whom no endovascular thrombectomy was initiated independently from the random assignment.The per-protocol population included patients who received the assigned treatment and had no clinically meaningful deviations from the protocol.This definition also excluded patients in whom central evaluation of baseline images by the image core lab resulted in an ASPECTS value below 3 or greater than 5.
For the functional outcome across the entire range of the mRS score, we used a proportional odds logistic regression model with adjustments for the randomisation stratification factors; mRS scores 0 and 1 were merged because of very low numbers in the medical treatment group.The proportional odds assumption was fulfilled; hence, the effect size is quantified by the common odds ratio (cOR; likelihood-ratio test) with the Wald 95% CI.Missing mRS values at 12 months were imputed (multiple imputation with five imputed datasets, combined using Rubin's method) using a proportional odds logistic regression model including baseline age, baseline NIHSS score, treatment group, and NIHSS score at hospital discharge, with the full conditional specification method, under the missing-at-random assumption, except for patients who died before 12 months, for whom an mRS score of 6 was assigned.We additionally did sensitivity analyses considering the worst-case and best-case scenarios.time from symptom onset to randomisation, ASPECTS according to the core laboratory evaluation, stroke cause, pre-treatment with intravenous thrombolysis, and site of vessel occlusion) was analysed by adding an interaction term between the treatment group and the baseline characteristics into the main model.Differences in binary outcomes (ie, based on mRS and PHQ-4) between groups were analysed using a logistic regression model, adjusted for randomisation stratification factors, and quantified using adjusted OR with the associated 95% CI.Differences in continuous outcomes between groups (ie, EQ-5L and PROMIS-10) were analysed using the Wilcoxon rank-sum test.For the outcome of overall survival, we used a Cox proportional-hazards model with the same adjustments as previous models to estimate the hazard ratio (95% CI); proportionality for this analysis was confirmed.
The statistical analysis plan contained no provisions for correction of secondary outcomes or for multiple comparisons in the subgroup analyses; hence, any p values are nominal and the 95% CIs reported should not be used for hypothesis testing.Statistical analyses were done using SAS (version 9.4).

Role of the funding source
The funder of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the report.

Results
Between July 17, 2018, and Feb 21, 2023, we recruited 253 patients (figure 1).We randomly assigned 125 (49%) patients to receive endovascular thrombectomy plus medical treatment and 128 (51%) to receive medical treatment only.Three (2%) patients assigned to receive medical treatment only crossed over and received thrombectomy.There were no crossovers among those assigned to receive thrombectomy.67 (26%) patients (28 [42%] from the thrombectomy group and 39 [58%] from the medical treatment only group) were excluded from the per-protocol analysis (appendix p 13). 2 Baseline characteristics were well balanced between groups, except for a slight imbalance in baseline ASPECTS values (table 1).Median follow-up was 8•36 months (IQR 0•02-12•00).Between follow-up at 90 days and at 12 months, only two additional participants were lost to follow-up (one in each group).Data on functional outcome were available for 244 (96%) of 253 patients at 12-month follow-up (123 [98%] of 125 in the thrombectomy group and 121 [95%] of 128 in the medical treatment only group), compared with 246 (97%) of 253 participants at the 90-day follow-up (figure 1).Functional outcome was imputed for nine patients (two in the thrombectomy group and seven in the medical treatment only group).
We found a shift in the distribution of mRS scores at 12 months, as assessed by the smRSq, towards better outcomes in favour of endovascular thrombectomy versus medical treatment only (adjusted common OR 2•39 [95% CI 1•47-3•90]; p=0•0004; figure 2; table 2).The proportional odds assumption was assessed and found to be valid.In the per-protocol sensitivity analysis of 97 patients who received thrombectomy and 89 patients who received medical treatment only, the result was similar, with the distribution of mRS scores at 12  The NIHSS is an ordinal scale that is used to assess the severity of stroke, with scores ranging from 0 to 42, and higher scores indicating greater neurological deficit.†Scores on the modified Rankin scale range from 0 to 6, with higher scores indicating greater disability.‡The M1 segment is the main trunk of the middle cerebral artery and the M2 segment is the first-order branch of the main trunk of the middle cerebral artery.§ASPECTS values range from 0 to 10, with lower values indicating larger infarction.).Subgroup analyses were generally supportive of the main analysis (appendix pp 13, 18).Given the imbalance in baseline ASPECTS between groups, we did a post-hoc exploratory analysis of distribution of mRS score at 12 months in the intentionto-treat population, adjusting for baseline ASPECTS, which yielded consistent results in favour of thrombectomy (adjusted common OR 2•34 [1•43-3•81]; p=0•0007; appendix p 22).

Table 1: Demographic and clinical characteristics of participants at baseline
In a post-hoc analysis, 27 (22%) of 123 patients assigned to endovascular thrombectomy had an mRS score of 0-2 at 12 months as compared with seven (6%) of 121 patients assigned to medical treatment only (adjusted OR 3•96 [95% CI 1•57-9•99]; p=0•0040; table 2).42 (34%) of 123 patients in the endovascular thrombectomy group had an mRS score of 0-3 at 12 months versus 20 (17%) of 121 in the medical treatment group (adjusted OR 2•42 [1•34-4•38]; p=0•0035).When comparing these findings with those at 90-days' follow-up, the number of patients with an mRS score of 0-2 at 12 months increased by six (5%) in the endovascular thrombectomy group and by four (3%) in the best medical treatment only group.The number of patients with an mRS score of 0-3 increased by three (2%) in the endovascular thrombectomy group and by four (3%) in the best medical treatment only group from 90 days to 12 months.
Figure 3 shows the change in mRS scores in patients in both groups from day 90 to 12 months.Among patients assigned to endovascular thrombectomy, 21 (17%) of 123 showed an improvement of at least one point on the mRS, compared with 13 (11%) of 118 patients assigned to medical treatment only.In 15 (12%) patients in the endovascular thrombectomy group and in nine (8%) in the medical treatment only group, the mRS score worsened by at least one point between day 90 and 12 months (appendix p 19).
In the analyses of patient-reported outcomes at 12 months, patients assigned to endovascular thrombectomy reported better quality of life than in the medical treatment only group, as assessed by median scores on the EQ-5D index (0 Outcomes Measurement Information System 10-item.*Intention-to-treat population (according to random assignment).†The treatment effect is reported for the functional outcome across the entire range of the mRS as an adjusted common odds ratio with the 95% CI for the ordinal shift in the distribution of scores on the mRS towards a better outcome with imputation of missing values; for PROMIS-10 and EQ-5D as Wilcoxon rank-sum test; for overall survival (censored at 12 months), as an adjusted hazard ratio with the 95% CI; and for other outcomes (mRS score ≤2, ≤3, and 4-6 at 12 months), as the adjusted odds ratio with the 95% CIs or as Wilcoxon ranksum test.Adjustments were for randomisation stratification factors.‡Scores on the mRS range from 0 to 6, with higher scores indicating greater disability.§Information was available for 63 (93%) of 68 stroke survivors in the endovascular treatment group and 42 (88%) of 48 in the medical treatment only group for EQ-5D index; for 58 (85%) in the endovascular treatment group and 37 (77%) in the medical treatment only group for EQ VAS; for 55 (81%) in the endovascular treatment group and 32 (67%) in the medical treatment only group for PROMIS global physical and mental health; and for 58 (85%) in the endovascular treatment group and 36 (75%) in the medical treatment only group for PHQ-4 anxiety and depression.¶Kaplan-Meier estimate.

Discussion
In the 12-month follow-up of the TENSION trial, the beneficial effect of endovascular thrombectomy in addition to medical treatment across the primary and secondary outcomes that was observed in the primary analysis at 90 days after index stroke was sustained at 12 months.Endovascular thrombectomy in addition to medical treatment in patients with a large brain infarction, defined as an ASPECTS of 3-5 due to large vessel occlusion of the anterior brain circulation, was associated with improved functional outcome, quality of life (on some self-reported measures), and overall survival at 12 months compared with medical treatment only.In post-hoc analyses, the proportions of patients with functional independence (mRS score 0-2) and being able to walk alone unaided (mRS score 0-3) at 12 months were higher in those assigned to endovascular thrombectomy compared with medical treatment only.Similarly, the proportion of patients dead or dependent at 12 months was lower with thrombectomy than with medical treatment only.These figures suggest that the improvement in overall survival with endovascular thrombectomy was not associated with a higher number of patients who are bedridden and completely dependent on the care of others.Our results showed a shift in outcomes from death and complete dependence to moderate disability in some patients with endovascular thrombectomy.The beneficial effect of endovascular thrombectomy in addition to medical treatment was consistent in the different analysis populations.
An important yet negative outcome of treatment for acute stroke is the possibility of saving the patient's life only for them to then live with major disability.Patientreported outcomes are, thus, essential to understand this possible outcome.At 12-month follow-up, stroke survivors in both study groups assessed their quality of life across different established measures.Better quality of life in the endovascular thrombectomy group than in the medical treatment only group was quantified by higher values on the EQ-5D index (comprising the dimensions mobility, self-care, usual activities, pain or discomfort, and anxiety or depression), on the EQ visual analogue scale (reflecting the subjective assessment of the current health state by a single value), and on the PROMIS-10 Global Physical Health score (scoring physical health and activities, fatigue, and pain).8][9] Patient-reported outcome measures have been shown to capture benefits of reperfusion treatment for acute ischaemic stroke beyond the improvement of   functional outcome. 13Based on our findings, endovascular thrombectomy has a clear benefit in severely affected patients with stroke, not only in terms of preventing death and disability, but also in terms of improving self-reported health outcomes including the assessment of activities, mobility, and fatigue.We also observed numerically better scores in the PROMIS-10 Global Mental Health score and lower rates of anxiety and depression at 12 months with endovascular thrombectomy, which were probably not significant because of the small sample size available for these comparisons.
In the SELECT2 trial of thrombectomy for large vessel occlusion stroke in the anterior circulation with large ischaemic core, 12-month follow-up showed similar results to ours, with sustained improvement of better functional outcome with thrombectomy versus control at 1 year after stroke, although in SELECT2, no significant effect of thrombectomy on mortality was observed. 9In two previous trials of thrombectomy for large vessel occlusion stroke in the anterior circulation, REVASCAT and MR CLEAN, a sustained improvement of functional outcome with thrombectomy similar to the observed effect at 90 days was reported at 1 year 7 or 2 years, 8 respectively.These trials differed from TENSION because they mostly included patients with only minor or moderate stroke lesions on imaging before treatmentie, patients who are well known to have high odds of favourable outcome with acute reperfusion treatment. 1ur results, together with those of SELECT2, are encouraging in that even the most severely affected patients with stroke with already-large ischaemic lesions before treatment showed sustained long-term benefit when treated with endovascular thrombectomy in addition to medical treatment.These findings are extended by the observation of a sustained benefit of thrombectomy at 6 months in the LASTE trial, 6 which included patients with large infarct, defined as an ASPECTS below 6 with no lower limit.
Our analysis provides new information about the trajectories of functional outcome after endovascular thrombectomy in patients with a large ischaemic stroke.This finding is of particular interest because the course of recovery from stroke symptoms is dynamic and might include improvements as well as complications and secondary deterioration even months after stroke. 14After thrombectomy, early courses of stroke symptoms are associated with functional outcome at 90 days. 15Data from broader stroke populations have shown that severe stroke symptoms are associated with worse long-term outcomes, 16 and patients with stroke with persistent severe disability also have an increased risk of secondary cardiovascular events and death. 17At the 12-month follow-up of the IMS III study, 18 patients with severe stroke (indicated by an NIHSS score of 20 or more) showed a continuous improvement in functional outcomes in the group receiving endovascular treatment, with a significant treatment benefit only becoming apparent after 12 months.
In our study, in both treatment groups, the proportion of patients in whom the mRS score improved by at least one point between 90 days and 12 months was higher than the number of patients in whom the score worsened.As a result, more patients in both treatment groups were independent or able to walk without assistance after 12 months (ie, mRS score ≤3) than was the case after 90 days.However, even within the thrombectomy group, in this population of patients with large infarct, the number of patients with independence at 12 months (ie, mRS score 0-2) was low.However, compared with the medical treatment only group, the absolute increase in the proportion of patients with functional independence at 12 months was 16%, translating into a number needed to treat of six for one patient to have functional independence with thrombectomy.This finding is in line with the absolute treatment benefit observed in the long-term follow-up of the SELECT2, 9 REVASCAT, 7 and MR CLEAN 8 trials.Furthermore, among patients receiving endovascular thrombectomy, the proportion of patients who were dependent or dead (ie, mRS score 4-6) was nominally lower at 12 months (66%) than at 90 days (69%).
Our findings might have practical implications for stroke centres worldwide.TENSION was designed to reflect clinical practice in most interventional stroke centres by relying on standard-of-care stroke imaging for guiding endovascular thrombectomy, which was CT and CT angiography in most centres, without the use of perfusion imaging, which is still only used for a minority of stroke patients receiving endovascular treatment. 19Even with this simple and pragmatic diagnostic algorithm, endovascular thrombectomy in patients with large infarct was safe and resulted in a significant long-term benefit in functional outcome.
Our study has limitations.Because the trial was stopped early for efficacy, the sample size was smaller than originally planned, limiting statistical power.We did not correct for multiple testing; therefore, these analyses of secondary endpoints should be considered exploratory and must not be used for hypothesis testing.The trial was not powered to assess differences in treatment effect across subgroups.Missing data for functional outcome were low, and only two patients were lost to follow-up between day 90 and 12 months; however, for the assessment of patient-reported outcome measures in stroke survivors at 12 months, the high amounts of missing data might result in substantial bias.Moreover, in the case of patients with severely disabling strokes, there might be limitations to the validity of patient-reported outcome measures.These individuals frequently have communication difficulties, cognitive impairments, or physical limitations that could affect their ability to accurately report their outcomes.Therefore, although patient-reported outcomes can still be valuable tools in assessing certain aspects of health-related quality of life in patients with stroke and severe disability, caution should be exercised in interpreting the results.
In conclusion, in the randomised TENSION trial, endovascular thrombectomy was associated with improved functional outcomes, survival, and quality of life at 12 months in patients with large vessel occlusion of the anterior circulation presenting with a large infarct on standard imaging compared with medical treatment only.These results show that the benefit of endovascular thrombectomy in patients with ischaemic stroke and a large infarct is sustained at 12 months.

Figure 1 :See
Figure 1: Trial profile Three patients assigned to receive medical treatment only crossed over and received thromectomy.mRS=modified Rankin Scale.

Figure 2 :
Figure 2: Distribution of mRS scores at 12 months (intention-to-treat analysis)A score of 0 on the mRS indicates no symptoms, a score of 1 indicates no clinically significant disability, a score of 2 indicates slight disability (patients are able to look after their own affairs without assistance but are unable to carry out all previous activities), a score of 3 indicates moderate disability (patients require some help but are able to walk unassisted), a score of 4 indicates moderately severe disability (patients are unable to attend to bodily needs without assistance and are unable to walk unassisted), a score of 5 indicates severe disability (patients require constant nursing care and attention), and a score of 6 indicates death.Percentages might not total 100 because of rounding.mRS=modified Rankin Scale.

Figure 3 :
Figure 3: Change in mRS scores from 90 days to 12 months (intention-to-treat population) mRS=modified Rankin scale.
months favouring Data are n (%), n/N (%), or median (IQR).Percentages might not total 100% because of rounding.ASPECTS=Alberta Stroke Program Early CT Score.NIHSS=National Institutes of Health Stroke Scale.*