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... Show moreBackground 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. Show less
BACKGROUND AND PURPOSE: Blinded outcome assessment in trials with prospective randomized open blinded end point design is challenging. Unblinding can result in misclassified outcomes and biased... Show moreBACKGROUND AND PURPOSE: Blinded outcome assessment in trials with prospective randomized open blinded end point design is challenging. Unblinding can result in misclassified outcomes and biased treatment effect estimates. An outcome adjudication committee assures blinded outcome assessment, but the added value for trials with prospective randomized open blinded end point design and subjective outcomes is unknown. We aimed to assess the degree of misclassification of modified Rankin Scale (mRS) scores by a central assessor and its impact on treatment effect estimates in a stroke trial with prospective randomized open blinded end point design.METHODS: We used data from the MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands). The primary outcome was the mRS at 90 days. Standardized, algorithm-based telephone interviews to assess the mRS were conducted from a central location by an experienced research nurse, unaware but not formally blinded to treatment allocation (central assessor). Masked reports of these interviews were adjudicated by a blinded outcome committee. Misclassification was defined as an incorrect classification of the mRS by the central assessor. The effect of endovascular treatment on the mRS was assessed with multivariable ordinal logistic regression.RESULTS: In MR CLEAN, 53/500 (10.6%) of the mRS scores were misclassified. The degree and direction of misclassification did not differ between treatment arms (P=0.59). Benefit of endovascular treatment was shown on the mRS when scored by the central assessor (adjusted common odds ratio, 1.60 [95% CI, 1.16-2.21]) and the outcome adjudication committee (adjusted common odds ratio, 1.67 [95% CI, 1.21-2.20]).CONCLUSIONS: Misclassification by the central assessor was small, randomly distributed over treatment arms, and did not affect treatment effect estimates. This study suggests that the added value of a blinded outcome adjudication committee is limited in a stroke trial with prospective randomized open blinded end point design applying standardized, algorithm-based outcome assessment by a central assessor, who is unaware but not formally blinded to treatment allocation. Show less
Li, Z.; Quartagno, M.; Bohringer, S.; Geloven, N. van 2021
Background The size of the margin strongly influences the required sample size in non-inferiority and equivalence trials. What is sometimes ignored, however, is that for trials with binary outcomes... Show moreBackground The size of the margin strongly influences the required sample size in non-inferiority and equivalence trials. What is sometimes ignored, however, is that for trials with binary outcomes, the scale of the margin - risk difference, risk ratio or odds ratio - also has a large impact on power and thus on sample size requirement. When considering several scales at the design stage of a trial, these sample size consequences should be taken into account. Sometimes, changing the scale may be needed at a later stage of a trial, for example, when the event proportion in the control arm turns out different from expected. Also after completion of a trial, a switch to another scale is sometimes made, for example, when using a regression model in a secondary analysis or when combining study results in a meta-analysis that requires unifying scales. The exact consequences of such switches are currently unknown. Methods and Results This article first outlines sample size consequences for different choices of analysis scale at the design stage of a trial. We add a new result on sample size requirement comparing the risk difference scale with the risk ratio scale. Then, we study two different approaches to changing the analysis scale after the trial has commenced: (1) mapping the original non-inferiority margin using the event proportion in the control arm that was anticipated at the design stage or (2) mapping the original non-inferiority margin using the observed event proportion in the control arm. We use simulations to illustrate consequences on type I and type II error rates. Methods are illustrated on the INES trial, a non-inferiority trial that compared single birth rates in subfertile couples after different fertility treatments. Our results demonstrate large differences in required sample size when choosing between risk difference, risk ratio and odds ratio scales at the design stage of non-inferiority trials. In some cases, the sample size requirement is twice as large on one scale compared with another. Changing the scale after commencing the trial using anticipated proportions mainly impacts type II error rate, whereas switching using observed proportions is not advised due to not maintaining type I error rate. Differences were more pronounced with larger margins. Conclusions Trialists should be aware that the analysis scale can have large impact on type I and type II error rates in non-inferiority trials. Show less
BACKGROUND: Cerebral white matter lesions (WMLs) have been associated with a greater risk of poor functional outcome after ischemic stroke. We assessed the relations between WML burden and... Show moreBACKGROUND: Cerebral white matter lesions (WMLs) have been associated with a greater risk of poor functional outcome after ischemic stroke. We assessed the relations between WML burden and radiological and clinical outcomes in patients treated with endovascular treatment in routine practice.METHODS: We analyzed data from the MR CLEAN Registry (Multicenter Randomized Controlled Trial of Endovascular Treatment for Acute Ischaemic Stroke in the Netherlands)-a prospective, multicenter, observational cohort study of patients treated with endovascular treatment in the Netherlands. WMLs were graded on baseline noncontrast computed tomography using a visual grading scale. The primary outcome was the score on the modified Rankin Scale at 90 days. Secondary outcomes included early neurological recovery, successful reperfusion (extended Thrombolysis in Cerebral Infarction >= 2b), futile recanalization (modified Rankin Scale score >= 3 despite successful reperfusion), and occurrence of symptomatic intracranial hemorrhage. We used multivariable logistic regression models to assess associations between WML severity and outcomes, taking the absence of WML on noncontrast computed tomography as the reference category.RESULTS: Of 3180 patients included in the MR CLEAN Registry between March 2014 and November 2017, WMLs were graded for 3046 patients and categorized as none (n=1855; 61%), mild (n=608; 20%), or moderate to severe (n=588; 19%). Favorable outcome (modified Rankin Scale score, 0-2) was achieved in 838 patients (49%) without WML, 192 patients (34%) with mild WML, and 130 patients (24%) with moderate-to-severe WML. Increasing WML grades were associated with a shift toward poorer functional outcome in a dose-dependent manner (adjusted common odds ratio, 1.34 [95% CI, 1.13-1.60] for mild WML and 1.67 [95% CI, 1.39-2.01] for moderate-to-severe WML; P-trend, <0.001). Increasing WML grades were associated with futile recanalization (P-trend, <0.001) and were inversely associated with early neurological recovery (P-trend, 0.041) but not with the probability of successful reperfusion or symptomatic intracranial hemorrhage.CONCLUSIONS: An increasing burden of WML at baseline is associated with poorer clinical outcomes after endovascular treatment for acute ischemic stroke but not with the probability of successful reperfusion or symptomatic intracranial hemorrhage. Show less
Background and Purpose:Ischemic brain tissue damage in patients with acute ischemic stroke, as measured by the Alberta Stroke Program Early CT Score (ASPECTS) may be more impactful in older than in... Show moreBackground and Purpose:Ischemic brain tissue damage in patients with acute ischemic stroke, as measured by the Alberta Stroke Program Early CT Score (ASPECTS) may be more impactful in older than in younger patients, although this has not been studied. We aimed to investigate a possible interaction effect between age and ASPECTS on functional outcome in acute ischemic stroke patients undergoing endovascular treatment, and compared reperfusion benefit across age and ASPECTS subgroups.Methods:Patients with ischemic stroke from the MR CLEAN Registry (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands; March 2014-November 2017) were included. Multivariable ordinal logistic regression was performed to obtain effect size estimates (adjusted common odds ratio) on functional outcome (modified Rankin Scale score) for continuous age and granular ASPECTS, with a 2-way multiplicative interaction term (agexASPECTS). Outcomes in four patient subgroups based on age (< versus >= median age [71.8 years]) and baseline ASPECTS (6-10 versus 0-5) were assessed.Results:We included 3279 patients. There was no interaction between age and ASPECTS on modified Rankin Scale (P=0.925). The highest proportion of modified Rankin Scale 5 to 6 was observed in patients >71.8 years with baseline ASPECTS 0 to 5 (68/107, 63.6%). There was benefit of reperfusion in all age-ASPECTS subgroups. Although the adjusted common odds ratio was lower in patients >71.8 years with ASPECTS 0 to 5 (adjusted common odds ratio, 1.60 [95% CI, 0.66-3.88], n=110), there was no significant difference from the main effect (P=0.299).Conclusions:Although the proportion of poor outcomes following endovascular treatment was highest in older patients with low baseline ASPECTS, outcomes did not significantly differ from the main effect. These results do not support withholding endovascular treatment based n a combination of high age and low ASPECTS. Show less
Background and Purpose:High-serum glucose on admission is a predictor of poor outcome after stroke. We assessed the association between glucose concentrations and clinical outcomes in patients who... Show moreBackground and Purpose:High-serum glucose on admission is a predictor of poor outcome after stroke. We assessed the association between glucose concentrations and clinical outcomes in patients who underwent endovascular treatment.Methods:From the MR CLEAN Registry, we selected consecutive adult patients with a large vessel occlusion of the anterior circulation who underwent endovascular treatment and for whom admission glucose levels were available. We assessed the association between admission glucose and the modified Rankin Scale score at 90 days, symptomatic intracranial hemorrhage and successful reperfusion rates. Hyperglycemia was defined as admission glucose >= 7.8 mmol/L. We evaluated the association between glucose and modified Rankin Scale using multivariable ordinal logistic regression and assessed whether successful reperfusion (extended Thrombolysis in Cerebral Infarction 2b-3) modified this association.Results:Of 3637 patients in the MR CLEAN Registry, 2908 were included. Median admission glucose concentration was 6.8 mmol/L (interquartile range, 5.9-8.1) and 882 patients (30%) had hyperglycemia. Hyperglycemia on admission was associated with a shift toward worse functional outcome (median modified Rankin Scale score 4 versus 3; adjusted common odds ratio, 1.69 [95% CI, 1.44-1.99]), increased mortality (40% versus 23%; adjusted odds ratio, 1.95 [95% CI, 1.60-2.38]), and an increased risk of symptomatic intracranial hemorrhage (9% versus 5%; adjusted odds ratio, 1.94 [95% CI, 1.41-2.66]) compared with nonhyperglycemic patients. The association between admission glucose levels and poor outcome (modified Rankin Scale score 3-6) was J-shaped. Hyperglycemia was not associated with the rate of successful reperfusion nor did successful reperfusion modify the association between glucose and functional outcome.Conclusions:Increased admission glucose is associated with poor functional outcome and an increased risk of symptomatic intracranial hemorrhage after endovascular treatment. Show less
Wiegers, E.J.A.; Mulder, M.J.H.L.; Jansen, I.G.H.; Venema, E.; Compagne, K.C.J.; Berkhemer, O.A.; ... ; Lugt, A. van der 2020
Background and Purpose-Collateral circulation status at baseline is associated with functional outcome after ischemic stroke and effect of endovascular treatment. We aimed to identify clinical and... Show moreBackground and Purpose-Collateral circulation status at baseline is associated with functional outcome after ischemic stroke and effect of endovascular treatment. We aimed to identify clinical and imaging determinants that are associated with collateral grade on baseline computed tomography angiography in patients with acute ischemic stroke due to an anterior circulation large vessel occlusion.Methods-Patients included in the MR CLEAN trial (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands; n=500) and MR CLEAN Registry (n=1488) were studied. Collateral status on baseline computed tomography angiography was scored from 0 (absent) to 3 (good). Multivariable ordinal logistic regression analyses were used to test the association of selected determinants with collateral status.Results-In total, 1988 patients were analyzed. Distribution of the collateral status was as follows: absent (7%, n=123), poor (32%, n=596), moderate (39%, n=735), and good (23%, n=422). Associations for a poor collateral status in a multivariable model existed for age (adjusted common odds ratio, 0.92 per 10 years [95% CI, 0.886-0.98]), male (adjusted common odds ratio, 0.64 [95% CI, 0.53-0.76]), blood glucose level (adjusted common odds ratio, 0.97 [95% CI, 0.95-1.00]), and occlusion of the intracranial segment of the internal carotid artery with occlusion of the terminus (adjusted common odds ratio 0.50 [95% CI, 0.41-0.61]). In contrast to previous studies, we did not find an association between cardiovascular risk factors and collateral status.Conclusions-Older age, male sex, high glucose levels, and intracranial internal carotid artery with occlusion of the terminus occlusions are associated with poor computed tomography angiography collateral grades in patients with acute ischemic stroke eligible for endovascular treatment. Show less
