Large Vessel Occlusion Acute Stroke Research Articles

Abstract WP80: Association of Clot Burden Score and Thrombectomy 6 to 24 Hours After Stroke: Analysis of the DAWN Trial

Introduction: Clot burden score (CBS) is developed to evaluate anterior circulation ischemic stroke thrombus extent. Lower CBS is associated with worse functional outcome in an analysis of MR CLEAN trial without modifying the effect of mechanical thrombectomy within 6 hours after symptoms onset. An analysis of SWIFT PRIME trial showed that stent-retriever thrombectomy successfully recanalize regardless of CBS. However, thrombus that remains stagnant for longer period may be further compressed by the water-hammer effect of the systolic blood pressure, resulting in removal difficulty. We aim to explore relation of CBS with mechanical thrombectomy (MT) in the extended 6-24 hours of the DAWN trial. Method: A blinded assessor evaluated CBS in all patients receiving CTA brain in the multicenter randomized DAWN trial for MT in acute large vessel occlusion last known well 6-24 hours (DWI or CTP Assessment with Clinical Mismatch in the Triage of Wake up and Late Presenting Strokes Undergoing Neurointervention). The cohort was divided into low CBS (0-4) and high CBS (5-10) groups. We used ordinal logistic regression for analysis of association with good outcome (mRS≤2), adjusted for significant baseline variables. Results: 143 patients were included. Low CBS group consisted of 50 patients (29 received MT and 21 received medical management). High CBS group consisted of 93 patients (44 received MT and 49 received medical management). Baseline demographics were similar between groups. Low CBS group showed no difference in the odd of good outcome, adjusted OR 0.58 (0.3-1.14). Analysis of MT cases, Low CBS group showed a strong trend to higher procedure time (81.5±55.2 versus 56.4±35.3 min, p=0.07). There was no association of Low CBS and odds of good outcome (OR 0.9; 0.27-2.92), successful recanalization (OR 0.58; 0.18-1.89), and symptomatic intracranial hemorrhage (OR 1.67, 0.55-5.09). Conclusion: Despite literature reporting worse outcome of anterior circulation ischemic stroke with low CBS, acute large vessel occlusion stroke with last known well 6-24 hours and low CBS treated with thrombectomy was feasible and not associated with worsen outcome compared to high CBS. However, a strong trend to higher procedure time is observed.

Abstract WMP45: Gene Expression Levels in Acute Large Vessel Occlusion Stroke in Humans

Background and Purpose: The Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC) tissue bank collects blood proximal and distal to the intracranial thrombus during the process of mechanical thrombectomy in human stroke patients. These samples provide a unique resource in evaluating acute gene expression changes at the time of ischemic stroke. The purpose of this study was to evaluate gene expression changes occurring within the thrombus and across the occlusion in the intravascular space in acute ischemic stroke patients. Methods: We developed the BACTRAC protocol: an IRB-approved tissue banking approach for ELVO (clinicaltrials.gov NCT03153683). We evaluated relative concentrations of gene expression in 84 inflammatory molecules in thrombi removed from adults who received thrombectomy for ischemic stroke, in static blood distal to thrombus, and in peripheral circulation. Results: We analyzed the first 46 subjects (age = 67 ± 14.23, 20 males) in the BACTRAC registry. Results from qPCR gene expression analyses demonstrate that 21 genes (CCL1, CCL11, CCL13, CCL17, CCL26, CCL8, CSF3, CX3CL1, CXCL1, CXCL9, IFNA2, IL13, IL17C, IL17F, IL1A, IL27, IL3, IL33, LTA, TNFSF11, and TNFSF13) had at least 25 mean fold change in the distal blood compared to the peripheral blood. Fourteen genes (AIMP1, CCL11, CCL13, CCL15, CCL16, CCL23, CCR2, CCR4, CCR8, CD40LG, CXCL10, IL10RA, IL15, and TNFSF13B) had at least 10 mean fold change in the thrombus compared to the peripheral blood. Overall, these genes are associated with chemo-attraction and cell proliferation of monocytes, neutrophils, and T cells. Conclusions: These findings provide a novel insight into the initial pathology of large vessel stroke in humans, particularly in regard to identifying acute gene expression changes that occur during stroke.

Abstract TP127: Impact of Smoking on Collateral Blood Flow in Patients With Acute Ischemic Stroke With Large Cerebral Artery Embolic Occlusion

Introduction: Good collateral flow is associated with improved outcomes in acute embolic stroke. There is compelling data linking smoking to all types of stroke, with current smokers at a higher risk than former or never smokers. Smoking has, however, been shown to promote collaterals in coronary vascular bed in humans. It is unknown if there is a similar effect in cerebral collateral flow. We aimed to investigate if cigarette smoking was positively associated with collateral blood flow in a homogenous cohort of patients with acute large vessel occlusive embolic stroke. Methods: We identified all patients aged ≥18 with acute ischemic stroke showing embolic occlusion of ICA terminus/M1 MCA on admission CT angiography (CTA), between 2008 to 2018, through an institutional database. Patients with chronic occlusions and stenotic lesions were excluded. Individual CTAs were independently reviewed by two trained investigators to calculate collateral scores of the affected hemisphere using the modified Tan scale (0-4) as a reference. Details of cigarette smoking history were obtained from the electronic medical records. Patients were grouped into smokers (former and current smokers) and never smokers. Odds ratios (OR) and their 95% confidence intervals (CI) were estimated, and all tests were considered significant when P<0.05. Results: Of the 612 patients identified through the database, 429/612 patients (mean age 71±16 years, 45% [194/429] women) satisfied the inclusion criteria. 64.8% (278/429) had a positive history of smoking with an average of 47±12 pack-years. There was a significant association between good collateral scores (≥2) with smoking history (OR 1.74 CI 1.17-2.61, P=0.006). This trend remained significant even after comparing raw collateral scores (0-4) ( P=0.006, Spearman’s ρ=0.22). However, number of pack-years and collateral scores exhibited no statistically significant relationship (P=0.6). Conclusions: Our study shows that patients who have ever smoked have higher intracranial collateral vessel scores in the event of an acute embolic stroke. Increased impedance and reduced cerebral blood flow resulting from cigarette smoking may stimulate collateral recruitment in cerebral pial circulation, similar to the effect in coronary bed.

308 Timeliness of Inter-Facility Transfer for Patients With Acute Large Vessel Occlusion Stroke

308 Timeliness of Inter-Facility Transfer for Patients With Acute Large Vessel Occlusion Stroke

Validation of iScore and PLAN Score for Death in Thrombectomy in Acute Stroke Due to Anterior Circulation Large Artery Occlusion

BackgroundTo validate iScore and PLAN score in acute anterior circulation large vessel occlusion stroke patients undergoing thrombectomy. MethodsiScore and PLAN score were calculated for consecutive acute ischemic stroke undergoing thrombectomy were included and death at 1 month and death at 3 months were recorded. The area under the receiver operating characteristic curve was used to assess the discrimination ability of the scales for death. ResultsTwo hundred and twenty-nine patients were included, 25.3% (58 of 229) of patient died at 1 month after thrombectomy and 25.8% (59 of 229) of them died at 3 months after thrombectomy. The receiver operator curve analysis found that iScore (area under the curve [AUC] = .76, 95% confidence interval [CI] .69-.83) was numerically better than PLAN score (AUC = .73, 95% CI .66-.81) for predicting death at day 90. The cut-off for iScore is 193, with sensitivity 64%, specificity 79%, positive predictive value 75% and negative predictive value 69%. ConclusionsThe iScore scale is a valid predictive tool for death in anterior circulation large vessel occlusions undergoing thrombectomy.

Automated CT Perfusion Prediction of Large Vessel Acute Stroke from Intracranial Atherosclerotic Disease

Background and Purpose: We have observed that large vessel occlusion acute strokes (LVOS) due to intracranial atherosclerotic disease (ICAD) present with more benign CT perfusion (CTP) profiles, which we presume to potentially represent enhanced collateralization compared to embolic LVOS. We aim to determine if CTP profiles can predict ICAD in LVOS. Methods: Retrospective review of a prospectively collected interventional stroke database from September 2010 to March 2015. Patients with intracranial ICA/MCA-M1/M2 occlusions and CTP were dichotomized into ICAD versus non-ICAD etiologies. Ischemic core (relative cerebral blood flow < 30%) and hypoperfusion volumes were estimated by automated CTP. Results: A total of 250 patients met the inclusion criteria, comprised of 21 (8%) ICAD and 229 non-ICAD etiologies. Baseline characteristics were similar between groups, except for higher HbA1c levels (p < 0.01), LDL cholesterol (p < 0.01), systolic blood pressure (p < 0.01), and lower rate of atrial fibrillation (p < 0.01) in ICAD patients. There were no significant differences in volumes of baseline ischemic core (p = 0.54) among groups. ICAD patients had smaller Tmax > 4 s, Tmax > 6 s, and Tmax > 10 s absolute lesions, and a higher ratio of Tmax > 4 s/Tmax > 6 s volumes (median 2 [1.6–2.3] vs. 1.6 [1.4–2.0]; p = 0.02). A Tmax > 4 s/Tmax > 6 s ratio ≥2 showed specificity = 73%/sensitivity = 52% for ICAD and was observed in 47.6% of ICAD versus 26.1% of non-ICAD patients (p = 0.07). Clinical outcomes were comparable amongst groups. Multivariate logistic regression revealed that Tmax > 4 s/Tmax > 6 s ratio ≥2 (OR 3.75, 95% CI 1.05–13.14, p = 0.04), higher LDL cholesterol (OR 1.1, 95% CI 1.01–1.03, p = 0.01), and higher systolic pressure (OR 1.03, 95% CI 1.01–1.04, p = 0.01) were independently associated with ICAD. Conclusion: An automated CTP Tmax > 4 s/Tmax > 6 s ratio ≥2 profile was found independently associated with underlying ICAD LVOS.

Neutrophil-Lymphocyte Ratio Predicts Functional and Safety Outcomes after Endovascular Treatment for Acute Ischemic Stroke

Background and Objective: Endovascular treatment (EVT) is proven to be safe and effective for treating acute large vessel occlusion stroke (LVOS). The neutrophil-lymphocyte ratio (NLR) reflects systemic inflammation, which plays an important role in the process of treating ischemic stroke. This study aims to explore the relationship between NLR and the clinical outcomes of LVOS patients undergoing EVT. Methods: Patients were selected from the EVT for acUte Anterior circuLation (ACTUAL) ischemic stroke registry. The laboratory data (neutrophil count, lymphocyte count) before EVT were collected. Poor functional outcome was defined as modified Rankin Scale (mRS) of 3–6 at 3 months. Multivariable logistic regression analyses were performed to explore the relationship of NLR with functional outcome, symptomatic intracranial hemorrhage (sICH), and mortality. Results: We eventually included 616 patients (median of age, 66 years; 40.3% female). There were 350 (56.7%) patients achieving mRS of 3–6 at 3 months, 98 (15.9%) patients with sICH, and the mortality at 3 months was 24.8% (153/616). Baseline NLR was independently associated with poor functional outcome (OR 1.58; 95% CI 1.02–2.45; p = 0.039) and sICH (OR 1.84; 95% CI 1.09–3.11; p = 0.023) but showed a trend for predicting 3-month mortality (OR 1.57; 95% CI 0.94–2.65; p = 0.088). Conclusions: NLR independently predicts 3-month functional outcome and sICH but the existence of a trend association with mortality after EVT for acute anterior circulation LVOS patients.

Mechanical thrombectomy for acute large vessel occlusion stroke with mild symptoms

Objective To evaluate the safety and efficacy of mechanical thrombectomy for acute large vessel occlusion stroke (LVO) with mild symptoms. Methods A retrospective analysis was conducted on 16 patients with LVO and National Institutes of Health Stroke Scale (NIHSS) score <6, who were admitted to Department of Neurosurgery, Xuanwu Hospital, Capital Medical University from April 2014 to November 2017. Among them, 5 cases had occlusion in middle cerebral artery (MCA) and included 2 cases in M1 and 3 cases in M2. In addition, there were 1 case with anterior cerebral artery (ACA) occlusion and 8 cases with vertebral-basilar artery occlusion. Besides thrombectomy, 6 cases with severe stenosis of large artery underwent acute angioplasty. Results Successful reperfusion[thrombolysis in cerebral infarction (TICI) score of 2b-3] was achieved in all 16 patients. One case developed symptomatic hemorrhage after recanalization. There were no procedure-related complications. At 90 days, 13 patients obtained good outcome: the modified Rankin scale (mRS) of 0 was reported in 8 patients, 1 in 2, 2 in 3 and 6 (death) in 1 case. Conclusion Endovascular mechanical thrombectomy appears to be safe and effective in patients presenting with mild stroke symptoms and acute large vessel occlusion. Key words: Stroke; Arterial occlusive diseases; Mild; Mechanical thrombectomy

Abstract WP17: Endovascular Therapy for Large Vessel Occlusion Acute Stroke in Nonagenarians versus Octogenarians

Background: Little is known on the outcomes of nonagenarians treated with endovascular therapy for acute large vessel occlusion stroke. It is unclear whether they have worse clinical outcomes than octogenarians. Methods: We reviewed our prospectively collected endovascular database at a tertiary care academic institution between Sep 2010-Dec 2016. All patients older than 80 years that underwent endovascular therapy for large vessel occlusion acute ischemic stroke were included and categorized into two groups: 80-89 years (octogenarians), and 90-99 years (nonagenarians). Baseline, procedural, and radiological characteristics, as well as outcome parameters were compared. Results: Thirty-one nonagenarians and 181 octogenarians were treated over the 6-year study period. When compared with octogenarians, nonagenarians had lower glucose levels (121±26 vs 138±46, p&lt;0.01) and were less often males (16% vs 34%, p=0.05). Other baseline characteristics including comorbidities, NIHSS, ASPECT scores and stroke location as well as procedural parameters were comparable between groups. In terms of outcomes, rates of successful reperfusion (mTICI 2b-3) (87.1% vs 87.9%, p=1.0), parenchymal hematomas (12.9% vs12.7%, p=1.0), and 90-day mortality (51.6% vs 41.4%, p=0.3) were comparable. There was a non-significant trend toward better 90-Day independent outcomes (modified Rankin scale, mRS 0-2) favoring octogenarians (12.9% vs 27.2%, p=0.09) while ambulatory outcomes were more similar (mRS 0-3) (29% vs 41.4%, p=0.2). In multivariate analysis, only baseline NIHSS (Beta -0.09 95%CI[-0.18_-0.02], p=0.02) and successful reperfusion (Beta 1.61 95%CI[0.16-21.23]) were associated with independent outcome. Conclusions: Our study shows that there is no significant difference in procedural and clinical outcomes between nonagenarians and octogenarians treated with endovascular therapy. Baseline stroke severity and successful reperfusion are the main drivers of favorable functional outcome in patients ≥80years old.

Abstract TMP3: Age-Adjusted Infarct Volume Cut-off For Favorable Outcome After Large Vessel Occlusion Stroke Endovascular Therapy

Background: Optimal selection paradigms for large vessel occlusion acute stroke endovascular therapy are yet to be established. Previous studies have shown the benefit of adjusting infarct size to age. We sought to study the impact of age-adjusted final infarct volumes (FIV), a surrogate for pre-reperfusion infarct core, on functional outcomes and determine the ideal thresholds for good outcome discrimination (90-day mRS 0-2). Methods: We reviewed our prospectively collected endovascular database at a tertiary care academic institution between 9/2010- 8/2016. All patients that underwent endovascular therapy for large vessel occlusion anterior circulation acute ischemic stroke were stratified into five age groups: (G1) &lt;50 years, (G2) 50-69, (G3) 70-79 (G4) 80-89 and (G5) ≥90. Baseline, procedural, and radiological characteristics, as well as outcome parameters were compared. FIV was measure on follow-up MRI or CT within 5 days of treatment. : 966 patients were studied (G1:136, G2:408, G3:233, G4:160, G5:29). Overall, the mean FIV was 59.9±79.9mL and 46% had good outcome. Patients with poor outcome had larger FIV in each group (Mean/Median[IQR]) (G1:46.8/29.2[8.7-64.6] vs 145.3/91.5[51.9-223.5], G2:26.9/15.8[7.7-37.2] vs 93.6/68.1[22.2-146.8], G3:26.2/17.6[7.6-34.1] vs 96.1/61.9[25.5-130.9], G4:14.7/8.7[3.9-16.4] vs 60.2/29[13.6-85.2], G5:2.9/1.3[0.6-4.3] vs 58.3/36.6[18.2-91.1], p&lt;0.01 for all). The target FIV cut-off (mL) decreased with increased age: G1:52.4(SE 75%, SP 65%); G2:23.2(SE 75%,SP 64%); G3:24.6(SE 76%,SP 64%); G4:13.4(SE 75%,SP 70%); G5:12.8(SE 79%,SP 100%). In multivariate analysis, after adjusting for age, baseline NIHSS, glucose level, reperfusion status, parenchymal hematoma and FIV, achieving a final infarct volume less than the age-adjusted target was an independent predictor of good outcome (OR:1.94 95%CI [1.06-3.53], p=0.03). Conclusions: Age-adjusted infarct volume represents a strong outcome discriminator substitute and might help refine patient selection for stroke endovascular therapy

Abstract 138: How Far is Too Far? A Decision Analysis Model of Pre-hospital Triage for Potential Large Vessel Occlusion Acute Stroke Patients

Background and Purpose: We sought to determine when transporting patients directly to a comprehensive stroke center (CSC; the “mothership”) is favorable compared to a “drip-and-ship” approach while accounting for the varying predictive abilities of pre-hospital large vessel occlusion (LVO) screening methods. Methods: We built a decision analysis model to compare anticipated functional outcomes for patients who are within IV-tPA treatment window in “mothership” and “drip-and-ship”. Key branches included IV-tPA eligibility, IV-tPA only or endovascular therapy (ET), successful reperfusion after ET, and treatment effects. In terms of the probability of requiring ET, we assessed three pre-hospital LVO screening methods: no LVO screening, the Rapid Arterial oCclusion Evaluation (RACE) Scale for Stroke, and in-ambulance CT angiography for LVO. Good outcome was defined as mRS 0-1 and, secondarily, mRS 0-2. Imputed probabilities and workflow times were extracted from published studies. We used one-way and two-way sensitivity analyses to vary two key inputs: time from onset to arrival at primary stroke center (PSC) and additional travel time to CSC. Results: The relative benefit of the “mothership” approach varied with the likelihood of pre-hospital LVO identification for outcome of mRS 0-1. In the absence of pre-hospital LVO screening, “drip-and-ship” was always favored. When pre-hospital CT angiography is used, “mothership” is always favored. When modeling the use of the RACE Scale for patients with onset-to-PSC arrival time less than 70 minutes, “mothership” was favored if the additional travel time to CSC was less than 21 minutes. When onset-to-PSC arrival time passed 70 minutes, “mothership” was favored for additional travel times up to 48 minutes (Figure). Conclusion: The results of our decision analysis model suggest that, in addition to transport times, pre-hospital LVO screening and time from stroke onset could influence triage decision making.

Clinical and Imaging Outcomes of Endovascular Therapy in Patients with Acute Large Vessel Occlusion Stroke and Mild Clinical Symptoms

Background: The minimal stroke severity justifying endovascular intervention remains elusive. However, a significant proportion of patients presenting with large vessel occlusion stroke (LVOS) and mild symptoms go untreated and face poor outcomes. We aimed to evaluate the clinical outcomes of patients presenting with LVOS and low symptom scores (National Institutes of Health Stroke Scale [NIHSS] score ≤8) undergoing endovascular therapy (ET). Methods: We performed a retrospective analysis of a prospectively collected ET database between September 2010 and March 2016. Endovascularly treated patients with LVOS and a baseline NIHSS score ≤8 were included. Baseline patient characteristics, procedural details, and outcome parameters were collected. Efficacy outcomes were the rate of good outcome (90-day modified Rankin Scale score 0-2) and of successful reperfusion (modified Treatment in Cerebral Infarction [mTICI] score 2b-3). Safety was assessed by the rate of parenchymal hematoma (parenchymal hematoma type 1 [PH-1] and parenchymal hematoma type 2 [PH-2]) and 90-day mortality. Logistic regression was used to identify predictors of good clinical outcomes. Results: A total of 935 patients were considered; 72 patients with an NIHSS score ≤8 were included. Median [IQR] age was 61.5 years [56.2-73.0]; 39 patients (54%) were men. Mean (SD) baseline NIHSS score, computed tomography perfusion core volume, and ASPECTS were 6.3 (1.5), 7.5 mL (16.1), and 8.5 (1.3), respectively. Twenty-eight patients (39%) received intravenous tissue plasminogen activator. Occlusions locations were as follows: 29 (40%) proximal MCA-M1, 20 (28%) MCA-M2, 6 (8%) ICA terminus, and 9 (13%) vertebrobasilar. Tandem occlusion was documented in 7 patients (10%). Sixty-seven patients (93%) achieved successful reperfusion (mTICI score 2b-3); 52 (72%) had good 90-day outcomes. Mean final infarct volume was 32.2 ± 59.9 mL. Parenchymal hematoma occurred in 4 patients (6%). Ninety-day mortality was 10% (n = 7). Logistic regression showed that only successful reperfusion (OR 27.7, 95% CI 1.1-655.5, p = 0.04) was an independent predictor of good outcomes. Conclusion: Our findings demonstrate that ET is safe and feasible for LVOS patients presenting with mild clinical syndromes. Future controlled studies are warranted.

Borderline Alberta Stroke Programme Early CT Score Patients with Acute Ischemic Stroke Due to Large Vessel Occlusion May Find Benefit with Endovascular Thrombectomy.

Selection of patients with acute ischemic stroke for endovascular thrombectomy (EVT) is complex and time-critical. Benefits of EVT are well established for patients with small core infarcts. The aim of this study was to compare clinical outcomes of EVT in patients with larger established infarcts (Alberta Stroke Programme Early CT Score [ASPECTS] ≤6) with patients with smaller infarcts (ASPECTS 7-10). The study included 355 patients with acute ischemic stroke due to large vessel occlusion who underwent EVT. ASPECTS was assigned to baseline noncontrast computed tomography, and collateral perfusion scores were assigned to multiphase computed tomography angiography. Baseline stroke severity, collateral grading, and clinical outcome data (complication rate, symptomatic intracranial hemorrhage and 90-day modified Rankin Scale score) were compared between patients with borderline (≤6) and high (7-10) ASPECTS. There were 34 (10%) patients with borderline ASPECTS. There was no difference in rate of good clinical outcome (37% vs. 46%, P= 0.852), symptomatic intracerebral hemorrhage (9% vs. 9%, P= 0.984), or mortality (20% vs. 22%, P= 0.818) between patients with borderline ASPECTS and high ASPECTS at 90 days. Moreover, there was no significant difference in collateral perfusion grade. This study identifies similar clinical benefit of EVT in patients with acute large vessel occlusion stroke with borderline ASPECTS and high ASPECTS.

Dwell Time of Stentriever Influences Complete Revascularization and First-Pass TICI 3 Revascularization in Acute Large Vessel Occlusive Stroke.

In acute ischemic stroke with large vessel occlusion, the interaction between the clot retriever and the stent is critical for achieving successful recanalization. The ideal time of stent deployment (dwell time [DT]) to improve revascularization is currently unknown. We systematically analyzed the effect of different DT on final angiographic and clinical outcomes of patients who underwent mechanical thrombectomy. The DT was progressively increased from 3 minutes to 5 minutes and then 8 minutes during the study period. The effect of DT on recanalization attempts, successful angiographic outcome (thrombolysis in cerebral ischemia [TICI] 2b or TICI 3), total revascularization time, and immediate and 3-month clinical outcomes were evaluated. The DT of 3 minutes and 5 minutes (DT3-5) was compared against DT of 8 minutes (DT8). Forty patients were included in the analysis. Good angiographic outcome was observed in 94.1% of patients in the DT8 cohort with an average attempt of 1.2 compared with 78.3% with average attempts of 2.0 in other group. Single-pass good recanalization (TICI 2b or 3) and single-pass complete revascularization (TICI3) was significantly higher in the DT group compared with the DT3-5 group (82.4% vs. 43.5% [P= 0.013] and 42.9% vs. 8.7% [P= 0.003], respectively). A favorable trend toward a reduced overall procedural time (34.59 vs. 55.59 minutes) was observed, but was not statistically significant (P= 0.15). Mild prolongation of DT to 8 minutes improves revascularization outcome with fewer attempts, possibly because of better clot-stent interaction.

Safety of the Solitaire 4×40mm Stent Retriever in the Treatment of Ischemic Stroke.

Stent retrievers apply mechanical force to the intracranial vasculature. Our aim was to evaluate the safety and efficacy of the long Solitaire 4×40mm stent retriever for large vessel occlusion in stroke patients. We conducted a retrospective analysis of all patients treated for acute ischemic large vessel occlusion stroke with the Solitaire 2 FR 4×40 device between May and October 2016 at our institution. Patient-specific data at baseline and at discharge were documented. Reperfusion was graded with the thrombolysis in cerebral infarction (TICI) classification. Postinterventional angiograms and follow-up cross-sectional imaging were used to evaluate complications. TICI 2b/3 recanalization was achieved in 20 of 23 patients (87.0%), in 17 patients with the first retriever pass. NIHSS improved from a mean score at presentation of 16 (range 4-36) to 11 (range 0-41) at discharge. Mean mRS score at discharge was 3 (range 0-6) and 3 (range 0-6) at 90days post-treatment. No infarcts in other territories were observed. One patient showed a (reversible) vasospasm in the postinterventional angiogram and another a small contrast extravasation in follow-up imaging. The Solitaire 2 FR 4×40 stent retriever is a safe and efficient device for large vessel occlusion acute ischemic stroke with a high recanalization rate and a low peri- and postinterventional complication rate together with a good clinical outcome. Despite potentially higher friction and shearing forces, no increased incidence of visible damage to the vessel wall was observed.

Deconstruction of Interhospital Transfer Workflow in Large Vessel Occlusion: Real-World Data in the Thrombectomy Era.

Interhospital transfer is a critical component in the treatment of acute anterior circulation large vessel occlusive stroke transferred for mechanical thrombectomy. Real-world data for benchmarking and theoretical modeling are limited. We sought to characterize transfer workflow from primary stroke center (PSC) to comprehensive stroke center after the publication of positive thrombectomy trials. Consecutive patients transferred from 3 high-volume PSCs to a single comprehensive stroke center between January 2015 and August 2016 were included in a retrospective study. Factors associated with key time metrics were analyzed with emphasis on PSC intrahospital workflow. Sixty-seven patients were identified. Median age was 74 years (interquartile range [IQR], 63.5-78) and National Institutes of Health Stroke Scale 17 (IQR, 12-21). Median transfer time measured by PSC-door-to-comprehensive stroke center-door was 128 minutes (IQR, 107-164), of which 82.8% was spent at PSCs (door-in-door-out [DIDO]; 106 minutes; IQR, 86-143). The lengthiest component of DIDO was computed-tomography-to-retrieval-request (median 59.5 minutes; IQR, 44-83). The 37.3% had DIDO exceeding 120 minutes. DIDO times differed significantly between PSCs (P=0.01). In multivariate analyses, rerecruiting the initial ambulance crew for transfer (P<0.01) and presentation during working hours (P=0.04) were associated with shorter DIDO times. In a metropolitan hub-and-spoke network, PSC-door-to-comprehensive stroke center-door and DIDO times are long even in high-volume PSCs. Improving PSC workflow represents a major opportunity to expedite mechanical thrombectomy and improve patient outcomes.

Abstract WMP23: Enhanced Collaterals in Patients with Large Vessel Stroke from Intracranial Atherosclerosis: An Automated CT Perfusion-based Study

Background and Purpose: Patients with intracranial atherosclerotic disease (ICAD) are believed to have enhanced collateral flow. We have anecdotally perceived that large vessel occlusion acute strokes (LVOS) patients due to ICAD have more benign automated CT perfusion (CTP) defect profiles, potentially reflecting improved collateralization in comparison to embolic LVOS. Methods: Retrospective review of a prospectively collected interventional stroke database from Sep 2010-Mar 2015. Patients were dichotomized into ICAD vs. other etiology. Patients with a technically adequate CTP and an intracranial ICA, MCA M1 or M2 occlusion were included. Tandem extracranial carotid occlusions were excluded due to the known effects on bolus dispersion and delay of bolus passage. Ischemic core (relative CBF&lt;30%) and perfusion defects were estimated by RAPID automated CTP. The primary endpoint was to compare the ratio of CTP Tmax&gt;4s (“benign oligemia”) / Tmax&gt;6s (“territory at risk”) between the two groups. Results: A total of 250 patients fit inclusion criteria, of whom 21 (8%) were classified as ICAD and 229 had other stroke etiologie. Baseline characteristics were similar between the two groups, except for higher hemoglobin A1c levels (p&lt;0.01), higher baseline systolic blood pressure (p&lt;0.01); and lower rates of atrial fibrillation (p&lt;0.01) in the ICAD group. There were no differences in ischemic core (p=0.51), perfusion defect Tmax&gt;4s (p=0.86), Tmax&gt;6s (p=0.57) and Tmax&gt;10s (p=0.17). ICAD patients had a median ratio of Tmax&gt;4s/ Tmax&gt;6s of 2. A Tmax&gt;4s/ Tmax&gt;6s ratio≥2 showed a specificity of 83% and a sensitivity of 52%, and was more common in the ICAD group (p=0.1). Multivariate logistic regression analysis revealed that higher rates of Tmax&gt;4s/ Tmax&gt;6s ratio≥2 (OR 3.36 95% CI 1.05-10.71, p=0.04), lower rates of atrial fibrillation(OR 0.17 95% CI 0.04-0.86, p=0.03), and higher systolic pressure (OR 1.03 95% CI 1.01-1.05, p=0.002) were independently associated with ICAD. Conclusion: A RAPID CTP Tmax&gt;4s/ Tmax&gt;6s ratio≥2 profile is an independent and highly specific indicator of underlying ICAD LVOS etiology.

Cost-Effectiveness of Endovascular Stroke Therapy: A Patient Subgroup Analysis From a US Healthcare Perspective.

Endovascular therapy in addition to standard care (EVT+SC) has been demonstrated to be more effective than SC in acute ischemic large vessel occlusion stroke. Our aim was to determine the cost-effectiveness of EVT+SC depending on patients' initial National Institutes of Health Stroke Scale (NIHSS) score, time from symptom onset, Alberta Stroke Program Early CT Score (ASPECTS), and occlusion location. A decision model based on Markov simulations estimated lifetime costs and quality-adjusted life years (QALYs) associated with both strategies applied in a US setting. Model input parameters were obtained from the literature, including recently pooled outcome data of 5 randomized controlled trials (ESCAPE [Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke], EXTEND-IA [Extending the Time for Thrombolysis in Emergency Neurological Deficits-Intra-Arterial], MR CLEAN [Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands], REVASCAT [Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting Within 8 Hours of Symptom Onset], and SWIFT PRIME [Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment]). Probabilistic sensitivity analysis was performed to estimate uncertainty of the model results. Net monetary benefits, incremental costs, incremental effectiveness, and incremental cost-effectiveness ratios were derived from the probabilistic sensitivity analysis. The willingness-to-pay was set to $50 000/QALY. Overall, EVT+SC was cost-effective compared with SC (incremental cost: $4938, incremental effectiveness: 1.59 QALYs, and incremental cost-effectiveness ratio: $3110/QALY) in 100% of simulations. In all patient subgroups, EVT+SC led to gained QALYs (range: 0.47-2.12), and mean incremental cost-effectiveness ratios were considered cost-effective. However, subgroups with ASPECTS ≤5 or with M2 occlusions showed considerably higher incremental cost-effectiveness ratios ($14 273/QALY and $28 812/QALY, respectively) and only reached suboptimal acceptability in the probabilistic sensitivity analysis (75.5% and 59.4%, respectively). All other subgroups had acceptability rates of 90% to 100%. EVT+SC is cost-effective in most subgroups. In patients with ASPECTS ≤5 or with M2 occlusions, cost-effectiveness remains uncertain based on current data.

Value of CT angiography in anterior circulation large vessel occlusive stroke: Imaging findings, pearls, and pitfalls

Hyperacute stroke imaging is playing an increasingly important role in determining management decisions in acute stroke patients, particularly patients with large vessel occlusive stroke who may benefit from endovascular intervention. CT angiography (CTA) is an important tool in the work-up of the acute stroke patient. It reliably detects large occlusive thrombi in proximal cerebral arteries and is a quick and highly accurate method in identifying candidates for endovascular stroke treatment. In this article we review the imaging findings on CTA in acute large vessel occlusive stroke using a pictorial case based approach. We retrospectively reviewed CTA studies in 48 patients presenting with acute anterior circulation large vessel occlusive stroke who were brought for intra-arterial acute stroke intervention. We discuss and illustrate patterns of proximal intracranial arterial occlusion, collateralization to the occluded territory, as well as reviewing some important pearls, pitfalls and teaching points in CTA assessment of the acute stroke patient. Performed from the level of the aortic arch CTA also gives valuable information regarding the state of other vessels in the acute stroke patient, identifying additional significant vascular stenoses or occlusions, and as we illustrate, can demonstrate other clinically significant findings which may impact on patient management and outcome.

Penumbra System: A Novel Mechanical Thrombectomy Device for Large-Vessel Occlusions in Acute Stroke

Large IC artery occlusion is often resistant to recanalization. We present our initial experience with the PS. Presenting with a severe acute ischemic stroke, the first 27 consecutive patients were considered for thromboaspiration therapy and retrospective data base analysis. All patients received standard thrombectomy treatment as monotherapy or in combination with thrombolysis or IC stent placement. The primary end point was revascularization of the target vessel to grade 2 or 3 on the TICI scale. Secondary end points were improvement of >4 points on the NIHSS score at discharge and favorable outcome, and improvement in overall mortality at 3 months and in sICH- and procedure-related adverse events. At baseline, the mean age was 66 +/- 14 years and the mean NIHSS score was 14 +/- 7. The anterior circulation was affected in 23 patients, and there were 4 basilar artery occlusions. Intracranial stent placement was performed in 4 patients. A recanalization to TICI 2 or 3 was achieved in 25 patients (93%). None of the patients developed sICH. At hospital discharge, 15 patients (56%) had an NIHSS improvement of >4 and 13 patients (48%) had an mRS score of <2 at 3 months. There was a significant correlation between complete vessel recanalization and favorable outcome. The all-cause mortality at 3 months was 11%. The PS showed a high potential for recanalization of acute thromboembolic occlusions of the large cerebral arteries. Complete recanalization was strongly correlated with good clinical outcome.