Sex differences in outcomes after endovascular treatment in posterior circulation stroke: results from the MR CLEAN Registry.

BACKGROUND: Women with anterior circulation large vessel occlusion (LVO) have been reported to have worse outcomes after endovascular treatment (EVT) than men. Whether these disparities also exist in LVO of the posterior circulation is yet uncertain. We assessed sex differences in clinical, technical, and safety outcomes of EVT in posterior circulation LVO. METHODS: We used data of patients with posterior circulation LVO included in the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) Registry (2014-2018). Primary outcome was the modified Rankin Scale (mRS) score at 90 days assessed with multivariable ordinal regression analysis. Secondary outcomes included favorable functional outcome (mRS ≤3), functional independence (mRS ≤2), death within 90 days, National Institutes of Health Stroke Scale (NIHSS) score 24-48 hours postintervention, complications, successful reperfusion (extended Thrombolysis in Cerebral Ischemia 2B-3), and procedure duration analyzed with multivariable logistic and linear regression analyses. RESULTS: We included 264 patients (42% women). Compared with men, women were older (median age 68 vs 63 years), more often had prestroke disability (mRS ≥1: 37% vs 30%), and received intravenous thrombolytics less often (45% vs 56%). Clinical outcomes were similar between sexes (adjusted (common) OR (aOR) 0.82, 95% CI 0.51 to 1.34; favorable functional outcome 50% vs 43%, aOR 1.31, 95% CI 0.77 to 2.25; death 32% vs 29%, aOR 0.98, 95% CI 0.52 to 1.84). In addition, NIHSS score after 24-48 hours (median 7 vs 9), successful reperfusion (77% vs 73%), and complications did not differ between men and women. CONCLUSIONS: Outcomes in women treated with EVT for posterior circulation LVO were similar compared with men despite less favorable baseline characteristics in women. Therefore men and women may benefit equally from EVT.

Outcome of patients with multivessel occlusion stroke after endovascular treatment.

INTRODUCTION: Little is known about the implications of multivessel occlusions (MVO) in large vessel occlusion stroke patients who undergo endovascular treatment (EVT). PATIENTS AND METHODS: We report data from the MR CLEAN Registry: a prospective, observational study on all stroke patients who underwent EVT in the Netherlands (March 2014-November 2017). We included patients with an intracranial target occlusion in the anterior circulation. An MVO was defined as an MCA occlusion (M1/M2) or intracranial ICA/ICA-T occlusion, with a concurrent second occlusion in the ACA or PCA territory confirmed on baseline CTA. To compare outcomes, we performed a 10:1 propensity score matching analysis with a logistic regression model including potential confounders. Outcome measures included 90-day functional outcome (modified Rankin Scale, mRS) and mortality. RESULTS: Of 2946 included patients, 71 patients (2.4%) had an MVO (87% concurrent ACA occlusion, 10% PCA occlusion, 3% ⩾3 occlusions). These patients were matched to 71 non-MVO patients. Before matching, MVO patients had a higher baseline NIHSS (median 18 vs 16, p = 0.001) and worse collateral status (absent collaterals: 17% vs 6%, p < 0.001) compared to non-MVO patients. After matching, MVO patients had worse functional outcome at 90 days (median mRS 5 vs 3, cOR 0.39; 95%CI 0.25-0.62). Mortality was higher in MVO patients (46% vs 27%, OR 2.11, 95%CI 1.24-3.57). DISCUSSION AND CONCLUSION: MVOs on baseline imaging were uncommon in LVO stroke patients undergoing EVT, but were associated with poor functional outcome.

Admission blood pressure and clinical outcomes in patients with acute ischaemic stroke treated with intravenous alteplase and endovascular treatment versus endovascular treatment alone: A MR CLEAN-NO IV substudy.

INTRODUCTION: High systolic blood pressure (SBP) is associated with poor functional outcome. We analysed whether the association of SBP with outcomes after endovascular treatment (EVT) is modified by prior intravenous thrombolysis (IVT). PATIENTS AND METHODS: This was a post-hoc analysis of MR CLEAN-NO IV, a randomised trial of IVT with alteplase followed by EVT versus EVT alone, within 4.5 h from stroke onset. SBP was recorded on hospital admission. The primary outcome was 90-day modified Rankin Scale (mRS) score and secondary outcomes included symptomatic intracranial haemorrhage (sICH) and successful reperfusion (eTICI 2b-3), analysed with (ordinal) logistic regression. Estimates were calculated per 10 mmHg change in SBP. We assessed whether IVT modified the associations of SBP with these outcomes using multiplicative interaction terms. RESULTS: Of 539 randomised patients, 266 received IVT. The association of SBP with mRS score was J-shaped, with an inflection point at 150 mmHg. Using 150 mmHg as a reference point, SBPs higher than 150 mmHg were associated with poor functional outcome (acOR: 1.23, 95% CI: 1.09-1.38), but lower SBPs were not (acOR: 1.14, 95% CI: 0.99-1.30). Higher SBP was not associated with the risk of sICH (aOR: 1.09, 95% CI: 0.93-1.27) nor with the probability of successful reperfusion (aOR: 1.00, 95% CI: 0.91-1.10). Our main result was that we found no effect modification by IVT (p-values for interaction, mRS = 0.94; sICH = 0.26; successful reperfusion = 0.58). DISCUSSION AND CONCLUSION: There was no effect modification of IVT with SBP for any of the clinical outcomes. Therefore, the level of SBP (if ⩽185/110 mmHg) should not guide IVT decisions in patients otherwise eligible for both IVT and EVT within the 4.5-h time window. TRIAL REGISTRATION: ISRCTN80619088, https://www.isrctn.com/ISRCTN80619088.

Cardiac thrombi detected by CT in patients with acute ischemic stroke: A substudy of Mind the Heart.

Background: Cardiac thrombi are a major risk factor for ischemic stroke, but are rarely diagnosed in the acute phase. We examined characteristics and functional outcome of patients with ischemic stroke and a concomitant cardiac thrombus detected on cardiac CT performed in the acute phase. Patients and Methods: We used data from "Mind the Heart," a prospective cohort study in which consecutive adult patients with acute ischemic stroke underwent prospective ECG-gated cardiac CT during their acute stroke imaging protocol. We compared characteristics, functional outcome (modified Rankin scale) and stroke recurrence rate at 90 days of patients with a cardiac thrombus on CT (defined as filling defect <100 Hounsfield Units) to those without a cardiac thrombus. Results: Among 452 included patients, cardiac CT detected 41 thrombi in 38 (8%) patients. Thrombi were most often located in the left atrial appendage (31/38 [82%]). Patients with a cardiac thrombus more frequently had intracranial occlusions in multiple vascular territories (5% vs 0.5%, p = 0.04) and a higher baseline NIHSS score (17 [IQR 6-22] vs 5 [IQR 2-3], p < 0.001) compared to patients without a cardiac thrombus. In 13/38 (34%) patients with a cardiac thrombus, no atrial fibrillation was detected. A cardiac thrombus was associated with worse functional outcome (adjusted common odds ratio 3.18 95%CI 1.68-6.00). Recurrence rate was not significantly different (8% vs 4%, aOR 1.50 (0.39-5.82). Discussion and Conclusion: Cardiac CT detected a cardiac thrombus in one in every 12 patients with acute ischemic stroke, and these patients had more severe deficits, multivessel occlusions, and a worse functional outcome.

Thrombus imaging characteristics within acute ischemic stroke: similarities and interdependence.

BACKGROUND: The effects of thrombus imaging characteristics on procedural and clinical outcomes after ischemic stroke are increasingly being studied. These thrombus characteristics - for eg, size, location, and density - are commonly analyzed as separate entities. However, it is known that some of these thrombus characteristics are strongly related. Multicollinearity can lead to unreliable prediction models. We aimed to determine the distribution, correlation and clustering of thrombus imaging characteristics based on a large dataset of anterior-circulation acute ischemic stroke patients. METHODS: We measured thrombus imaging characteristics in the MR CLEAN Registry dataset, which included occlusion location, distance from the intracranial carotid artery to the thrombus (DT), thrombus length, density, perviousness, and clot burden score (CBS). We assessed intercorrelations with Spearman's coefficient (ρ) and grouped thrombi based on 1) occlusion location and 2) thrombus length, density and perviousness using unsupervised clustering. RESULTS: We included 934 patients, of which 22% had an internal carotid artery (ICA) occlusion, 61% M1, 16% M2, and 1% another occlusion location. All thrombus characteristics were significantly correlated. Higher CBS was strongly correlated with longer DT (ρ=0.67, p<0.01), and moderately correlated with shorter thrombus length (ρ=-0.41, p<0.01). In more proximal occlusion locations, thrombi were significantly longer, denser, and less pervious. Unsupervised clustering analysis resulted in four thrombus groups; however, the cohesion within and distinction between the groups were weak. CONCLUSIONS: Thrombus imaging characteristics are significantly intercorrelated - strong correlations should be considered in future predictive modeling studies. Clustering analysis showed there are no distinct thrombus archetypes - novel treatments should consider this thrombus variability.

Timing of symptomatic intracranial hemorrhage after endovascular stroke treatment.

Introduction: Little is known about the timing of occurrence of symptomatic intracranial hemorrhage (sICH) after endovascular therapy (EVT) for acute ischemic stroke. A better understanding could optimize in-hospital surveillance time points and duration. The aim of this study was to delineate the probability of sICH over time and to identify factors associated with its timing. Patients and methods: We retrospectively analyzed data from the Dutch MR CLEAN trial and MR CLEAN Registry. We included adult patients who underwent EVT for an anterior circulation large vessel occlusion within 6.5 h of stroke onset. In patients with sICH (defined as ICH causing an increase of ⩾4 points on the National Institutes of Health Stroke Scale [NIHSS]), univariable and multivariable linear regression analysis was used to identify factors associated with the timing of sICH. This was defined as the time between end of EVT and the time of first CT-scan on which ICH was seen as a proxy. Results: SICH occurred in 205 (6%) of 3391 included patients. Median time from end of EVT procedure to sICH detection on NCCT was 9.0 [IQR 2.9-22.5] hours, with a rapidly decreasing incidence after 24 h. None of the analyzed factors, including baseline NIHSS, intravenous alteplase treatment, and poor reperfusion at the end of the procedure were associated with the timing of sICH. Conclusion: SICHs primarily occur in the first hours after EVT, and less frequently beyond 24 h. Guidelines that recommend to perform frequent neurological assessments for at least 24 h after intravenous alteplase treatment can be applied to ischemic stroke patients treated with EVT.

Cost-effectiveness of CT perfusion for patients with acute ischemic stroke (CLEOPATRA)-Study protocol for a healthcare evaluation study.

Introduction: Computed tomography perfusion (CTP) is variably considered to assess eligibility for endovascular thrombectomy (EVT) in acute ischemic (AIS) stroke patients. Although CTP is recommended for patient selection in later (6-24 h) time window, it is currently not recommended in the earlier (0-6 h) time window and the costs and health effects of including CTP for EVT selection remain unknown. We aim to estimate the costs and health effects of using CTP for EVT selection in AIS patients compared to conventional selection. Patients and methods: CLEOPATRA is a healthcare evaluation study using clinical and imaging data from multiple, prospective EVT trials and registries in both the earlier and later time windows. To study the long-term health and cost effects, we will construct a ("Markov") health state transition model simulating the clinical outcome over a 5-year follow-up period for CTP-based and conventional selection for EVT. Clinical data acquired within the current study and estimates from the literature will be used as input for probabilities of events, costs, and Quality-Adjusted Life Years (QALYs) per modified Rankin Scale (mRS) subscore. Primary outcome for the cost-effectiveness analysis will be the Incremental Cost-Effectiveness Ratio (ICER) in terms of costs per QALY gained over the simulated follow-up period. Study outcomes: Outcome measures will be reported as cumulative values over a 5-year follow-up period. Discussion: This study will provide preliminary insight into costs and health effects of including CTP in the selection for EVT for AIS patients, presenting between 0 and 24 h after time last known well. The results may be used to develop recommendations and inform further implementation projects and studies.

The prognostic value of extracranial vascular characteristics on procedural duration and revascularization success in endovascularly treated acute ischemic stroke patients.

Introduction: Vascular anatomy might affect endovascular treatment success in acute ischemic stroke patients with large vessel occlusion. We investigated the prognostic value of extracranial vascular characteristics on procedural time and revascularization success in patients with large vessel occlusion in the anterior cerebral circulation. Patients and methods: We included 828 patients endovascularly treated within 6.5 hours of symptom onset from the Dutch MR CLEAN-Registry. We evaluated aortic arch configuration, stenosis and tortuosity of supra-aortic arteries, and internal carotid arteries (ICAs) on pre-intervention CTA. We constructed logistic prediction models for outcome variables procedural duration (≥60 minutes) and non-successful revascularization (extended thrombolysis in cerebral infarction (eTICI) of 0-2A) using baseline characteristics and assessed the effect of extracranial vascular characteristics on model performance. Results: Cervical ICA tortuosity and stenosis ≥99% improved prediction of long procedural duration compared with baseline characteristics from area under the curve of 0.61 (95% CI: 0.57-0.65) to 0.66 (95% CI: 0.62-0.70) (P < 0.001). Cervical ICA tortuosity was significantly associated with non-successful recanalization. Prediction of non-successful revascularization did not improve after including aortic arch elongation, acute take-off angle, aortic variant, origin stenosis of supra-aortic arteries, and cervical ICA tortuosity, with an area under the curve of 0.63 (95% CI: 0.59-0.67) compared with 0.59 (95% CI: 0.55-0.63) (P = 0.11). Conclusion: Extracranial vascular characteristics have additional prognostic value for procedural duration, but not for revascularization success, compared with baseline characteristics. Performance of both prediction models is limited in patients treated for large vessel occlusion.

Occult blood flow patterns distal to an occluded artery in acute ischemic stroke.

Residual blood flow distal to an arterial occlusion in patients with acute ischemic stroke (AIS) is associated with favorable patient outcome. Both collateral flow and thrombus permeability may contribute to such residual flow. We propose a method for discriminating between these two mechanisms, based on determining the direction of flow in multiple branches distal to the occluding thrombus using dynamic Computed Tomography Angiography (dynamic CTA). We analyzed dynamic CTA data of 30 AIS patients and present patient-specific cases that identify typical blood flow patterns and velocities. We distinguished patterns with anterograde (N = 10), retrograde (N = 9), and both flow directions (N = 11), with a large variability in velocities for each flow pattern. The observed flow patterns reflect the interplay between permeability and collaterals. The presented method characterizes distal flow and provides a tool to study patient-specific distal tissue perfusion.

Worldwide anaesthesia use during endovascular treatment for medium vessel occlusion stroke.

INTRODUCTION: The optimal anaesthesia approach for endovascular treatment (EVT) in acute ischaemic stroke is currently unknown. In stroke due to medium vessel occlusions (MeVO), the occluded vessels are particularly small and more difficult to access, especially in restless or uncooperative patients. In these patients, general anaesthesia (GA) may be preferred by physicians to prevent complications due to patient movement. We investigated physicians' approaches to anaesthesia during EVT for MeVO stroke. METHODS: In a worldwide, case-based, online survey, physicians' preferred anaesthesia approach during EVT for MeVO stroke was categorized as "initial GA", "initial GA if necessary" (depending on patient cooperation), "no initial GA, but conversion if necessary" (start with local anaesthesia or conscious sedation), and "no GA". Preferred anaesthesia approaches were reported overall and stratified by physician and patient characteristics. RESULTS: A total of 366 survey participants provided 1464 responses to 4 primary MeVO EVT case-scenarios. One-third of responses (489/1464 [33%]) favoured no initial GA, but conversion if necessary. Both initial GA and initial GA if necessary were preferred in 368/1464 (25%) of responses respectively. No GA was favoured in 244/1464 (17%). Occlusion location, respondent specialization (interventional neuroradiology), higher age, and female respondent sex were significantly associated with GA preference. GA was more often used in Europe than in other parts of the world (p < 0.001). CONCLUSIONS: Anaesthesia approaches in MeVO EVT vary across world regions and patient and physician factors. Most physicians in this survey preferred to start with local anaesthesia or conscious sedation and convert to GA if necessary.

Brain atrophy and endovascular treatment effect in acute ischemic stroke: a secondary analysis of the MR CLEAN trial.

BACKGROUND: Brain atrophy is suggested to impair the potential for functional recovery after acute ischemic stroke. We assessed whether the effect of endovascular treatment is modified by brain atrophy in patients with acute ischemic stroke due to large vessel occlusion. METHODS: We used data from MR CLEAN, a multicenter trial including patients with acute ischemic stroke due to anterior circulation large vessel occlusion randomized to endovascular treatment plus medical care (intervention) versus medical care alone (control). We segmented total brain volume (TBV) and intracranial volume (ICV) on baseline non-contrast computed tomography (n = 410). Next, we determined the degree of atrophy as the proportion of brain volume in relation to head size (1 - TBV/ICV) × 100%, analyzed as continuous variable and in tertiles. The primary outcome was a shift towards better functional outcome on the modified Rankin Scale expressed as adjusted common odds ratio. Treatment effect modification was tested using an interaction term between brain atrophy (as continuous variable) and treatment allocation. RESULTS: We found that brain atrophy significantly modified the effect of endovascular treatment on functional outcome (P for interaction = 0.04). Endovascular treatment led to larger shifts towards better functional outcome in the higher compared to the lower range of atrophy (adjusted common odds ratio, 1.86 [95% CI: 0.97-3.56] in the lowest tertile vs. 1.97 [95% CI: 1.03-3.74] in the middle tertile vs. 3.15 [95% CI: 1.59-6.24] in the highest tertile). CONCLUSION: Benefit of endovascular treatment is larger in the higher compared to the lower range of atrophy, demonstrating that advanced atrophy should not be used as an argument to withhold endovascular treatment.

qTICI: Quantitative assessment of brain tissue reperfusion on digital subtraction angiograms of acute ischemic stroke patients.

BACKGROUND: The Thrombolysis in Cerebral Infarction (TICI) scale is an important outcome measure to evaluate the quality of endovascular stroke therapy. The TICI scale is ordinal and observer-dependent, which may result in suboptimal prediction of patient outcome and inconsistent reperfusion grading. AIMS: We present a semi-automated quantitative reperfusion measure (quantified TICI (qTICI)) using image processing techniques based on the TICI methodology. METHODS: We included patients with an intracranial proximal large vessel occlusion with complete, good quality runs of anteroposterior and lateral digital subtraction angiography from the MR CLEAN Registry. For each vessel occlusion, we identified the target downstream territory and automatically segmented the reperfused area in the target downstream territory on final digital subtraction angiography. qTICI was defined as the percentage of reperfused area in target downstream territory. The value of qTICI and extended TICI (eTICI) in predicting favorable functional outcome (modified Rankin Scale 0-2) was compared using area under receiver operating characteristics curve and binary logistic regression analysis unadjusted and adjusted for known prognostic factors. RESULTS: In total, 408 patients with M1 or internal carotid artery occlusion were included. The median qTICI was 78 (interquartile range 58-88) and 215 patients (53%) had an eTICI of 2C or higher. qTICI was comparable to eTICI in predicting favorable outcome with area under receiver operating characteristics curve of 0.63 vs. 0.62 (P = 0.8) and 0.87 vs. 0.86 (P = 0.87), for the unadjusted and adjusted analysis, respectively. In the adjusted regression analyses, both qTICI and eTICI were independently associated with functional outcome. CONCLUSION: qTICI provides a quantitative measure of reperfusion with similar prognostic value for functional outcome to eTICI score.

The association between computed tomography angiography timing and workflow times in patients with acute ischemic stroke.

BACKGROUND: In most hospitals, computed tomography angiography (CTA) is nowadays routinely performed in patients with acute ischemic stroke. However, it is unclear whether CTA is best performed before or after start of intravenous thrombolysis (IVT), since acquisition of CTA before IVT may prolong door-to-needle times, while acquisition after IVT may prolong door-to-groin times in patients undergoing endovascular treatment. METHODS: We performed a before-versus-after study (CTA following IVT, period I and CTA prior to IVT, period II), consisting of two periods of one year each. This study is based on a prospective registry of consecutive patients treated with IVT in two collaborating high-volume stroke centers; one primary stroke center and one comprehensive stroke center. The primary outcome was door-to-needle times. Secondary outcomes included door-to-groin times. Quantile regression analyses were performed to evaluate the association between timing of CTA and workflow times, adjusted for prognostic factors. RESULTS: A total of 519 patients received IVT during the study period (246 in period I, 273 in period II). In the adjusted analysis, we found a nonsignificant 1.13 min median difference in door-to-needle times (95% confidence interval: 1.03-3.29). Door-to-groin times was significantly shorter in period II in both unadjusted and adjusted analysis with the latter showing a 19.16 min median difference (95% confidence interval: 3.08-35.24). CONCLUSIONS: CTA acquisition prior to start of IVT did not adversely affect door-to-needle times. However, a significantly shorter door-to-groin times was observed in endovascular treatment eligible patients. Performing CTA prior to start of IVT seems the preferred strategy.

Prior antiplatelet therapy in patients undergoing endovascular treatment for acute ischemic stroke: Results from the MR CLEAN Registry.

BACKGROUND: Antiplatelet therapy may increase the risk of symptomatic intracranial hemorrhage after endovascular treatment for ischemic stroke but may also have a beneficial effect on functional outcome. The aim of this study is to compare safety and efficacy outcomes after endovascular treatment in patients with and without prior antiplatelet therapy. METHODS: We analyzed patients registered in the MR CLEAN Registry between March 2014 and November 2017, for whom data on antiplatelet therapy were available. We used propensity score nearest-neighbor matching with replacement to balance the probability of receiving prior antiplatelet therapy between the prior antiplatelet therapy and no prior antiplatelet therapy group and adjusted for baseline prognostic factors to compare these groups. Primary outcome was symptomatic intracranial hemorrhage. Secondary outcomes were 90-day functional outcome (modified Rankin Scale), successful reperfusion (extended thrombolysis in cerebral infarction score ≥2B) and 90-day mortality. RESULTS: Thirty percent (n = 937) of the 3154 patients were on prior antiplatelet therapy, who were matched to 477 patients not on prior antiplatelet therapy. Symptomatic intracranial hemorrhage occurred in 74/937 (7.9%) patients on prior antiplatelet therapy and in 27/477 (5.6%) patients without prior antiplatelet therapy adjusted odds ratio 1.47, 95% confidence interval 0.86-2.49. No associations were found between prior antiplatelet therapy and functional outcome (adjusted common odds ratio 0.87, 95% confidence interval 0.65-1.16), successful reperfusion (adjusted odds ratio 1.23, 95% confidence interval 0.77-1.97), or 90-day mortality (adjusted odds ratio 1.15, 95% confidence interval 0.86-1.54). CONCLUSION: We found no evidence of an association of prior antiplatelet therapy with the risk of symptomatic intracranial hemorrhage after endovascular treatment, nor on functional outcome, reperfusion, or mortality. A substantial beneficial or detrimental effect of antiplatelet therapy on clinical outcome cannot be excluded. A randomized clinical trial comparing antiplatelet therapy versus no antiplatelet therapy is needed.

Aortic dissection masquerading as a code stroke: A single-centre cohort study.

INTRODUCTION: Data on the incidence of acute aortic dissection in the code stroke population are scarce. We report estimated incidence, clinical manifestations, treatment and outcomes of patients with an acute aortic dissection in a code stroke cohort from a comprehensive stroke centre. PATIENTS AND METHODS: We used data from a single-centre prospective registry of consecutive adult patients who presented to the emergency department between 2015 and 2018 with neurological deficits suggestive of an acute stroke ('code stroke'). All patients routinely underwent non-contrast computed tomography of the brain and computed tomography-angiography of the aortic arch, cervical and intracranial arteries. RESULTS: Of 2874 code stroke patients, 1563 (54.4%) had acute ischaemia (ischaemic stroke or transient ischaemic attack). Fifteen patients (0.5% of code stroke patients and 0.8% of patients with acute ischaemia) had an acute aortic dissection (all Stanford classification type A). Discerning clinical manifestations were decreased consciousness in 11/15 (73%), pain in 8/15 (53%) and low systolic blood pressure (mean 106 mmHg, SD30). Acute aortic dissection was an incidental finding during computed tomography-angiography in 4/15 (27%). Two out of 15 patients (13%) received intravenous thrombolysis, 9/15 (60%) underwent aortic surgery and 10/15 (67%) died. Of those who survived, 3/5 (60%) had a good functional outcome (modified Rankin Scale 0-2). DISCUSSION AND CONCLUSION: In our comprehensive stroke centre, about 1/200 code stroke patients and 1/125 patients with acute ischaemia had an acute aortic dissection. Multicentre studies are necessary to acquire a more reliable estimate of the incidence of acute aortic dissection in the code stroke population. Given the ramifications of missing this diagnosis, imaging of the entire aortic arch is important in these patients.

Early detection of small volume stroke and thromboembolic sources with computed tomography: Rationale and design of the ENCLOSE study.

BACKGROUND: Computed tomography is the most frequently used imaging modality in acute stroke imaging protocols. Detection of small volume infarcts in the brain and cardioembolic sources of stroke is difficult with current computed tomography protocols. Furthermore, the role of computed tomography findings to predict recurrent ischemic stroke is unclear. With ENCLOSE, we aim to improve (1) the detection of small volume infarcts with thin slice computed tomography perfusion (CTP) images and thromboembolic source with cardiac computed tomography techniques in the acute stage of ischemic stroke and (2) prediction of recurrent ischemic stroke with computed tomography-derived predictors.Methods/design: ENCLOSE is a prospective multicenter observational cohort study, which will be conducted in three Dutch stroke centers (ClinicalTrials.gov Identifier: NCT04019483). Patients (≥18 years) with suspected acute ischemic stroke who undergo computed tomography imaging within 9 h after symptom onset are eligible. Computed tomography imaging includes non-contrast CT, CTP, and computed tomography angiography (CTA) from base of the heart to the top of the brain. Dual-energy CT data will be acquired when possible, and thin-slice CTP reconstructions will be obtained in addition to standard 5 mm CTP data. CTP data will be processed with commercially available software and locally developed model-based methods. The post-processed thin-slice CTP images will be compared to the standard CTP images and to magnetic resonance diffusion-weighted imaging performed within 48 h after admission. Detection of cardioembolic sources of stroke will be evaluated on the CTA images. Recurrence will be evaluated 90 days and two years after the index event. The added value of imaging findings to prognostic models for recurrent ischemic stroke will be evaluated. CONCLUSION: The aim of ENCLOSE is to improve early detection of small volume stroke and thromboembolic sources and to improve prediction of recurrence in patients with acute ischemic stroke.

Mind the Heart: Electrocardiography-gated cardiac computed tomography-angiography in acute ischaemic stroke-rationale and study design.

RATIONALE: About one-third of ischaemic strokes are caused by cardioembolism, and a substantial proportion of cryptogenic strokes likely also originate from the heart or aortic arch. Early determination of aetiology is important to optimise management. Computed Tomography-angiography of the heart is emerging as an alternative to echocardiography to detect cardio-aortic sources of embolism in stroke patients, but its diagnostic yield in acute ischaemic stroke has not been thoroughly assessed.Hypothesis: We hypothesise that electrocardiography-gated computed tomography-angiography of the heart and aortic arch, acquired in the acute phase in patients with ischaemic stroke, has a higher diagnostic yield than transthoracic echocardiography as a first-line screening method for detection of cardio-aortic sources of embolism. METHODS AND DESIGN: Mind the Heart is a single-centre prospective observational cohort study. We will include consecutive adult patients with acute ischaemic stroke who are potentially eligible for reperfusion therapy. Patients undergo non-electrocardiography-gated computed tomography-angiography of the aortic arch, cervical and intracranial arteries, directly followed by prospective sequential electrocardiography-gated cardiac computed tomography-angiography. Routine work-up for cardioembolism including 12-leads electrocardiography, Holter electrocardiography and transthoracic echocardiography is performed as soon as possible. The primary endpoint is the proportion of patients with a predefined high-risk cardio-aortic source of embolism on computed tomography-angiography versus transthoracic echocardiography in patients who underwent both investigations. Based on an expected 5% additional yield of computed tomography-angiography, a sample size of 450 patients is required. CONCLUSIONS: The Mind the Heart study will generate a reliable estimate of the diagnostic yield of echocardiography-gated cardio-aortic computed tomography-angiography performed in the acute phase of ischaemic stroke.

TRIAGE-STROKE: Treatment strategy In Acute larGE vessel occlusion: Prioritize IV or endovascular treatment-A randomized trial.

RATIONALE: For patients with acute ischemic stroke and large vessel occlusions, intravenous thrombolysis and endovascular therapy are standard of care, but the effect of endovascular therapy is superior to intravenous thrombolysis. If a severe stroke with symptoms indicating large vessel occlusions occurs in the catchment area of a primary stroke center, there is equipoise regarding optimal transport strategy. AIM: For patients presenting with suspected large vessel occlusions (PASS ≥ 2) and a final diagnosis of acute ischemic stroke, we hypothesize that bypassing the primary stroke center will result in an improved 90-day functional outcome. SAMPLE SIZE: We aim to randomize 600 patients, 1:1. DESIGN: A national investigator-driven, multi-center, randomized assessor-blinded clinical trial. The Prehospital Acute Stroke Severity Scale has been developed. It identifies most patients with large vessel occlusions in the pre-hospital setting. Patients without a contraindication for intravenous thrombolysis are randomized to either transport directly to a comprehensive stroke centers for intravenous thrombolysis and of endovascular therapy or to a primary stroke center for intravenous thrombolysis and subsequent transport to a comprehensive stroke centers for of endovascular therapy, if needed. OUTCOMES: The primary outcome will be the 90-day modified Rankin Scale score (mRS) for all patients with acute ischemic stroke. Secondary outcomes include 90-day mRS for all randomized patients, all patients with ischemic stroke but without large vessel occlusions, and patients with hemorrhagic stroke. The safety outcomes include severe dependency or death and time to intravenous thrombolysis for ischemic stroke patients. DISCUSSION: Study results will influence decision making regarding transport strategy for patients with suspected large vessel occlusions.

Direct Intra-arterial thrombectomy in order to Revascularize AIS patients with large vessel occlusion Efficiently in Chinese Tertiary hospitals: A Multicenter randomized clinical Trial (DIRECT-MT)-Protocol.

RATIONALE: Intravenous thrombolysis combined with mechanical thrombectomy (MT) has been proven safe and clinical effective in patients with acute ischemic stroke of anterior circulation large vessel occlusion. However, despite reperfusion, a considerable proportion of patients do not recover. Incidence of symptomatic intracerebral hemorrhage was similar between patients treated with the combination of intravenous thrombolysis and MT, as compared to intravenous thrombolysis alone, suggesting that this complication should be attributed to pre-treatment with intravenous thrombolysis. Conversely, intravenous thrombolysis may be beneficial in patients with small clots occluding intracranial arteries with underlying intracranial atherosclerotic disease, not accessible for MT. AIM: To assess whether direct MT is non-inferior compared to combined intravenous thrombolysis plus MT in patients with AIS due to an anterior circulation large vessel occlusion, and to assess treatment effect modification by presence of intracranial atherosclerotic disease. SAMPLE SIZE: Aim to randomize 636 patients 1:1 to receive direct MT (intervention) or combined intravenous thrombolysis plus MT (control). DESIGN: This is a multicenter, prospective, open label parallel group trial with blinded outcome assessment (PROBE design) assessing non-inferiority of direct MT compared to combined intravenous thrombolysis plus MT. OUTCOMES: The primary outcome is the score on the modified Rankin Scale assessed blindly at 90 (±14) days. An common odds ratio, adjusted for the prognostic factors (age, NIHSS, collateral score), representing the shift on the 6-category mRS scale measured at three months, estimated with ordinal logistic regression, will be the primary effect parameter. Non-inferiority is established if the lower boundary of the 95% confidence interval does not cross 0.8. DISCUSSION: DIRECT-MT could result in improved therapeutic efficiency and cost reduction in treatment of anterior circulation large vessel occlusion stroke.

Impact of single phase CT angiography collateral status on functional outcome over time: results from the MR CLEAN Registry.

BACKGROUND: Collateral status modified the effect of endovascular treatment (EVT) for stroke in several randomized trials. We assessed the association between collaterals and functional outcome in EVT treated patients and investigated if this association is time dependent. METHODS: We included consecutive patients from the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in The Netherlands (MR CLEAN) Registry (March 2014-June 2016) with an anterior circulation large vessel occlusion undergoing EVT. Functional outcome was measured on the modified Rankin Scale (mRS) at 90 days. We investigated the association between collaterals and mRS in the MR CLEAN Registry with ordinal logistic regression and if this association was time dependent with an interaction term. Additionally, we determined modification of EVT effect by collaterals compared with MR CLEAN controls, and also investigated if this was time dependent with multiplicative interaction terms. RESULTS: 1412 patients were analyzed. Functional independence (mRS score of 0-2) was achieved in 13% of patients with grade 0 collaterals, in 27% with grade 1, in 46% with grade 2, and in 53% with grade 3. Collaterals were significantly associated with mRS (adjusted common OR 1.5 (95% CI 1.4 to 1.7)) and significantly modified EVT benefit (P=0.04). None of the effects were time dependent. Better collaterals corresponded to lower mortality (P<0.001), but not to lower rates of symptomatic intracranial hemorrhage (P=0.14). CONCLUSION: In routine clinical practice, better collateral status is associated with better functional outcome and greater treatment benefit in EVT treated acute ischemic stroke patients, independent of time to treatment. Within the 6 hour time window, a substantial proportion of patients with absent and poor collaterals can still achieve functional independence.