Emergent Large Vessel Occlusion Patients Research Articles

Abstract WP29: A Propensity-Matched Analysis of Outcomes for Patients With M2 Branch Occlusions at Endovascular Stroke Centers

Introduction: Endovascular therapy (EVT) for Emergent Large Vessel Occlusion (ELVO) is recommended for patients with acute proximal MCA (M1 segment) occlusions (Class I, level A evidence), but the benefits of EVT are uncertain in patients with M2 and more distal occlusions. The purpose of this study was to compare the efficacy and outcomes of EVT-treated M2 ELVOs with EVT-treated M1 ELVOs, and to examine the outcomes of EVT-trerated M2 ELVO patients with those whose M2 ELVOs were not treated. Methods: Data were obtained from a multi-hospital system of patients from January 2014 and May 2018. Two propensity score (PS)-based nearest-neighbor matching analyses were used to match similar patients who had 1) EVT-treated M1 vs EVT-treated M2 ELVOs and 2) EVT-treated vs non-EVT-treated M2 ELVOs. Outcomes included length of stay (LOS), rate of successful reperfusion, discharge disposition, symptomatic intracranial hemorrhage (sICH), and discharge mRS. Chi-squared, Fisher’s exact, and Mann-Whitney U tests were used to compare matched patients. Results: Overall, 160 patients with EVT-treated M2 ELVOs, 350 with EVT-treated M1 ELVOs, and 113 with non-EVT-treated M2 ELVOs were included. Propensity score analyses resulted in 118 matched patients with EVT-treated M2 and EVT-treated M1 occlusions and 70 matched patients with EVT-treated and non-EVT-treated M2 ELVOs. M2 ELVOs made up 20% of all LVO patients. Treated M1 and M2 ELVOs were similar with respect to baseline NIHSS and outcomes. When attempted, intra-arterial reperfusion of M2 ELVOs was achieved at comparable rates to M1 ELVOs with equal rates of sICH (1.7%). Higher NIHSS was associated with EVT of M2 ELVOs (15.00[8.50,21.00] vs 7.00[4.00,17.75]; p<0.001). Rates of mortality trended more favorably in treated M2 ELVOs (12.9% vs 20%), which was not statistically significant (p=0.362). Conclusions: EVT for M2 ELVOs is as safe and effective as EVT for M1 vessel ELVOs. Rates of successful reperfusion, discharge mRS, LOS, sICH, discharge disposition and mortality are similar among EVT treated M2 and EVT treated M1 ELVOs. Though not statistically significant, EVT for patients with M2 ELVOs resulted in favorable trends toward higher survival rates of potential clinical significance.

Abstract TP67: Acute Blood Pressure Changes Aggravate Ischemic Lesion Growth After Large Vessel Occlusion

Backgrounds: Penumbral perfusion dynamically changes with alterations of collateral flow and systemic blood pressure. We investigated the association between acute changes of systolic blood pressures and infarct growth within penumbral area. Method: We included ischemic stroke patients <24h after onset from Jan 2015 to Mar 2018 with the following criteria; initial NIHSS score ≥ 6-point, internal carotid or middle cerebral artery occlusion, no recanalization treatment, baseline penumbral volume >15 mL, and mismatch ratio >1.8. Perfusion quantification, 3D voxel-registration and image segmentation were done by Olea 3.0 and Analyze 12.0. Penumbra was defined as Tmax >6s lesion without infarct. Infarct growth within penumbra was defined by the infarct volume at a follow-up image. Hypoperfusion intensity ratio (HIR) was defined by the proportion of Tmax >10s within penumbra. Blood pressure change integral (BPCI) was defined by an integration of SBP initial - SBP trajectory over 24 h (Figure A). BP dropmax was defined by a maximum decrease of SBP between successive measurements. Results: Among 25 patients included (age, 71.3±13.5; male, 56%), median baseline NIHSS score was 13 (interquartile range [IQR], 8-18). Median volume of initial infarct within Tmax >6s was 16 mL (IQR, 6-58), penumbra was 80 mL (IQR, 29-138), HIR was 46% (IQR, 31-63), and infarct growth within penumbra was 26% (IQR, 11-48). Median BPCI was 157.4 mmHg·h (IQR, -76.8-566.2) and BP dropmax was 34 mmHg (IQR, 25-43). Median infarct growth was linearly associated with BPCI (β=0.022; p -value=0.03; Figure B), BP dropmax (β=0.77; p -value=0.048; Figure C), and HIR (β=0.69; p -value<0.01). High dichotomized BPCI and BP dropmax increased infarct growth rate (Figure D). Conclusions: Acute decline of systemic blood pressure may aggravates penumbral perfusion and thus increase infarct growth within penumbral tissue in emergent large vessel occlusion patients without recanalization.

Abstract TP61: Could Fazekas Score Serve as a Predictor of Functional Outcomes in ELVO Patients Undergoing Mechanical Thrombectomy?

Objective: To evaluate the association between cerebral small vessel disease (CSVD) burden and degree of disability based on modified Rankin Score at 90 days, in patients presenting with emergent large vessel occlusion (ELVO) within 6 hours of last known well. Methods: We conducted a retrospective analysis of all patients presenting with an ELVO between May 2016 and July 2018. Patients with a TICI score of 2b or 3 were included and evaluated for CSVD burden as quantified by white matter hyperintensities in the non-affected hemisphere, on T2-FLAIR MRI using the Fazekas score (0-3). 90-day modified Rankin Scale scores (mRS, range 0-6) and patient information was collected from the Houston Methodist Hospital Outcomes Based Prospective Endpoints in Stroke (HOPES) registry. Results: 138 patients were evaluated, TICI 2b/3 was achieved in 114, and 84 patients were able to undergo MRI. Factors excluding patients from MRI included: medical instability, implantable devices, and death. All 84 patients were successfully re-evaluated at 90 days and divided into two cohorts, functionally independent (mRS 0-2) and functional dependent/deceased (mRS 3-6). Among the 84 patients, 37 (mean age 69.4y [SD, 14.5]; 54% female) were determined to be functionally independent (14, mRS 0; 19, mRS 1; 4, mRS 2) with the average Fazekas score for each subclass and the cohort; (mRS 0, 1.07; mRS 1, 0.89; mRS 2, 1; 0.97). The remaining 47 patients (mean age 71.1y [SD, 15.8]; 55% female) were determined to have a significant degree of disability, or were deceased (8, mRS 3; 10, mRS 4; 15, mRS 5; 14, mRS 6). Average Fazekas scores were (mRS 3, 1.75; mRS 4, 1.90; mRS 5, 2.13; mRS 6, 1.93; 1.96). Potentially confounding variables, including the use of intravenous alteplase (78% vs. 76%), and door to groin puncture time (204m [SD, 74m] vs. 206m [SD, 54m]) were found to be non-significant contributors. Conclusion: Based on our analytical cohort of ELVO patients undergoing thrombectomy, CSVD burden, classified by Fazekas score on T2-FLAIR MRI, was found to correlate with worse 90-day mRS. These results may be explained by potentially poor cerebrovascular reserve and diminished collateral blood flow in patients with greater CVSD burden.

Design, Application and Infield Validation of a Pre-Hospital Emergent Large Vessel Occlusion Screening Tool: Ventura Emergent Large Vessel Occlusion Score

Background: The outcome of endovascular treatment for emergent large vessel occlusion (ELVO) is dependent on timely recanalization. To identify ELVO in the field, we present a simplified score, which has been applied and validated in the field by emergency medical services (EMS). Methods and Analysis: Ventura ELVO Scale (VES) comprise of 4 components: Eye Deviation, Aphasia, Neglect, and Obtundation with score range 0-4. The score of greater than or equal to 1 will be considered as ELVO positive. A positive VES along with positive Cincinnati scale prompts ELVO activation. EMS then notify to neurointervention protocol at the receiving stroke center. The performance of VES was evaluated retrospectively. For statistical analysis, SAS version 9.4 was used and Fisher's modelling was used for the comparative analysis. Results: Total 184 patients were included in the final analysis, 62 (33.7%) patients were called VES positive from the field. Out of 62, 36 (58%) patients had ELVO. The mean NIHSS on arrival was 16 in VES positive and 5 in VES negative patients. VES was 94.7% sensitive and 82.4% specific while the PPV and NPV of VES were 58.1% and 98.4%, respectively. It showed 84.9% accuracy. Conclusions: VES is an effective and simplified prehospital screening tool for detection of ELVO in the field. Its implementation can beat the target door to groin time to improve outcomes and in future it can be used for rerouting of ELVO patients to comprehensive stroke center.

Emergency medical systems education may improve knowledge of pre-hospital stroke triage protocols

BackgroundFollowing the results of randomized clinical trials supporting the use of mechanical thrombectomy (MT) with tissue plasminogen activator for emergent large vessel occlusion (ELVO), our state Stroke Task Force convened...

Door-in-Door-Out Time at Primary Stroke Centers May Predict Outcome for Emergent Large Vessel Occlusion Patients.

Background and Purpose- Interfacility transfers for thrombectomy in stroke patients with emergent large vessel occlusion (ELVO) are associated with longer treatment times and worse outcomes. In this series, we examined the association between Primary Stroke Center (PSC) door-in to door-out (DIDO) times and outcomes for confirmed ELVO stroke transfers and factors that may modify the interaction. Methods- We retrospectively identified 160 patients transferred to a single Comprehensive Stroke Center (CSC) with anterior circulation ELVO between July 1, 2015 and May 30, 2017. We included patients with acute occlusions of the internal carotid artery or proximal middle cerebral artery (M1 or M2 segments), with a National Institutes of Health Stroke Scale score of ≥6. Workflow metrics included time from onset to recanalization, PSC DIDO, interfacility transfer time, CSC arrival to arterial puncture, and arterial puncture to recanalization. Primary outcome measure was National Institutes of Health Stroke Scale at discharge and modified Rankin Scale (mRS) score at 90 days. Results- The median (Q1-Q3) age and National Institutes of Health Stroke Scale of the 130 ELVO transfers analyzed was 75 (64-84) and 17 (11-22). Intravenous alteplase was administered to 64% of patients. Regarding specific workflow metrics, median (Q1-Q3) times (in minutes) were 241 (199-332) for onset to recanalization, 85 (68-111) for PSC DIDO, 26 (17-32) for interfacility transport, 21 (16-39) for CSC door to arterial puncture, and 24 (15-35) for puncture to recanalization. Median discharge National Institutes of Health Stroke Scale score was 5 (2-16), and 46 (35%) patients had a favorable outcome at 90 days. Complete reperfusion (modified Thrombolysis in Cerebral Ischemia 2c/3) modified the deleterious association of DIDO on outcome. Conclusions- For patients diagnosed with ELVO at a PSC who are being transferred to a CSC for thrombectomy, longer DIDO times may have a deleterious effect on outcomes and may represent the single biggest modifiable factor in onset to recanalization time. PSCs should make efforts to decrease DIDO and routine use of DIDO as a performance measure is encouraged.

Mechanical thrombectomy outcomes in large vessel stroke with high international normalized ratio

ObjectiveEvaluating the safety and efficacy of mechanical thrombectomy (MT) in acute stroke patients due to emergent large vessel occlusion (ELVO) with high international-normalized-ratio (INR). MethodsConsecutive ELVO patients treated with MT were evaluated from two centers. Outcome measures included symptomatic-intracranial-hemorrhage(sICH), three-month mortality, successful reperfusion(SR), and 3-month functional-independence(FI; mRS-scores of 0–2). Additionally, a meta-analysis of available cohort studies was performed to evaluate safety and efficacy of MT in ELVO patients with high INR. ResultsA total of 315 ELVO patients were evaluated. Of those 10 patients had INR >1.7 [mean age 63.5 ± 15, median NIHSS-score: 17 points (IQR 14–22)],and remaining 305 ELVO patients had INR ≤ 1.7 ([mean age 62 ± 14.4, median NIHSS-score: 17 points (IQR 12–21)]. Patients with high INR did not differ in terms of sICH (10.0% vs. 6.9%; p = .706), 3-month mortality (20.0% vs. 24.2%; p = .762), SR (88.9% vs. 69.4%; p = .209) and 3-month FI (50% vs. 49.3%; p = .762) compared to the rest. Meta-analysis of available studies (n = 5) showed that high INR was not related to sICH (OR: 0.94, 95%CI: 0.42–2.07; p = .88), 3-month mortality (OR: 1.07, 95%CI: CI 0.72–1.60; p = .73) and 3-month FI (OR: 0.69, 95%CI: 0.34–1.40; p = .30). ConclusionsMT can be performed safely and effectively in ELVO patients with high INR.

Direct Thrombectomy versus Bridging for Patients with Emergent Large-Vessel Occlusions

Background and Aims: Patients with emergent large-vessel occlusion (ELVO) that present earlier than 4 h from onset are usually treated with bridging systemic thrombolysis followed by endovascular thrombectomy (EVT). Whether direct EVT (dEVT) could improve the chances of favorable outcome remains unknown. Methods: Consecutively, prospectively enrolled patients with ELVO presenting within 4 h of onset were entered into a National Acute Stroke Registry of patients undergoing revascularization. Patients treated with bridging were compared to those treated with dEVT. Excellent outcome was defined as having a modified Rankin Scale score ≤1 at 90 days following stroke. Results: Out of 392 patients that underwent thrombectomy, 270 (68%) presented within 4 h and were included. Of those, 159 (59%) underwent bridging and 111 (41%) underwent dEVT. Atrial fibrillation and congestive heart failure were more common in the dEVT group (43 vs. 30%, p = 0.04 and 20 vs. 8%, p = 0.009, respectively), but other risk factors, demographics, stroke severity and subtypes as well as baseline vessel patency state and time metrics did not differ. Excellent target vessel recanalization defined as TICI 3 (thrombolysis in cerebral infarction score) was more common in the dEVT group (75 vs. 61%, p = 0.03), but in-hospital mortality, discharge destinations, short- and long-term excellent outcome rates did not differ. On multivariate regression analysis, treatment modality did not significantly modify the chances of excellent outcome at discharge (OR 0.7; 95% CI 0.3–1.5) or at 3 months (OR 0.78 95% CI 0.4–1.4). Conclusions: The chances of attaining excellent functional outcomes are similar in ELVO patients undergoing dEVT or bridging.

Comparative safety and efficacy of combined IVT and MT with direct MT in large vessel occlusion.

In this multicenter study, we sought to evaluate comparative safety and efficacy of combined IV thrombolysis (IVT) and mechanical thrombectomy (MT) vs direct MT in emergent large vessel occlusion (ELVO) patients. Consecutive ELVO patients treated with MT at 6 high-volume endovascular centers were evaluated. Standard safety and efficacy outcomes (successful reperfusion [modified Thrombolysis in Cerebral Infarction IIb/III], functional independence [FI] [modified Rankin Scale (mRS) score of 0-2 at 3 months], favorable functional outcome [mRS of 0-1 at 3 months], functional improvement [mRS shift by 1-point decrease in mRS score]) were compared between patients who underwent combined IVT and MT vs MT alone. Additional propensity score-matched analyses were performed. A total of 292 and 277 patients were treated with combination therapy and direct MT, respectively. The combination therapy group had greater functional improvement (p = 0.037) at 3 months. After propensity score matching, 104 patients in the direct MT group were matched to 208 patients in the combination therapy group. IVT pretreatment was independently (p < 0.05) associated with higher odds of FI (odds ratio [OR] 1.75; 95% confidence interval [CI] 1.02-2.99) and functional improvement (common OR 1.64; 95% CI 1.05-2.56). Combination therapy was independently (p < 0.05) related to lower likelihood of 3-month mortality (0.50; 95% CI 0.26-0.96). This observational study provides preliminary evidence that IVT pretreatment may improve outcomes in ELVO patients treated with MT. The question of the potential effect of IVT on ELVO patients treated with MT should be addressed with a randomized controlled trial. This study provides Class III evidence that for stroke patients with emergent large vessel occlusion, combined IVT and MT is superior to direct MT in improving functional outcomes.

Abstract 83: Successful Recanalization With Intravenous Thrombolysis Preceding Mechanical Thrombectomy in Large Vessel Occlusions: A Systematic Review and Meta-Analysis

Introduction: Although current guidelines advocate pretreatment with intravenous thrombolysis (IVT) in all eligible patients with emergent large vessel occlusion (ELVO) prior to mechanical thrombectomy (MT), there are observational data questioning the efficacy of IVT pretreatment in patients with ELVO. One of the main arguments in favour of IVT pretreatment is the potential for tPA-induced successful recanalization (SR) before the onset of endovascular procedure averting the need for MT. Methods: We performed a systematic review in MEDLINE and SCOPUS databases for randomized clinical trials (RCTs) and observational cohorts providing rates of SR with IVT in patients with ELVO before the initiation of MT. We also performed subgroup analyses according to study type (RCTs or observational) and according to the inclusion per-protocol of patients with tandem (intracranial/extracranial) occlusions. Results: We identified 10 eligible studies (7 RCTs &amp; 3 observational cohorts), including 1227 ELVO patients (median NIHSS score: 17). SR following IVT and before MT was documented in 9% (95%CI: 5%-14%; I 2 =85.4%) of ELVO patients, with no significant (p=0.263) differences among RCTs and observational cohorts (Figure). Higher tPA-induced SR rates were identified in studies reporting exclusion of patients with tandem occlusions compared to the rest (15%, 95%CI: 6%-26% vs 5%, 95%CI: 2%-9%; p for subgroup difference=0.052). Conclusions: Pretreatment with IVT in ELVO patients eligible for MT results in SR in almost one out of ten cases, negating the need for additional endovascular reperfusion. Tandem occlusions appear to be the least responsive to IVT pretreatment.

Abstract 145: Thrombus Composition is Associated With Endothelial Injury and Stroke Etiology in Patients Undergoing Mechanical Thrombectomy for Emergent Large Vessel Occlusion

Introduction: High rates of recanalization of Emergent Large Vessel Occlusion (ELVO) provide an opportunity to examine retrieved thrombi. We studied device and endothelial (ET) interactions to evaluate ET injury and the relationship between thrombi and Acute Ischemic Stroke (AIS) mechanism. Methods: Prospective registry examining immunohistochemical characteristics of retrieved thrombi in ELVO patients. Thrombi were categorized histopathologically and ET injury quantified by CD34 staining and immunohistochemistry, ELISA and reverse transcribed quantitative PCR to detect ET components. ET mRNA expression of CD31 was quantified from thrombi RNA. Plasma at the thrombectomy site was tested for ET derived biomarkers: microparticles (MPs), soluble Intercellular Cell Adhesion Molecule-1 (sICAM1) and soluble Thrombomodulin (sTM). Statistical analysis was performed with unpaired student’s t-tests and chi-square tests. Results: Twenty-five patients (age 68±3 , NIHSS 16±2, 48% female) were enrolled. The most common sites of occlusion were the MCA (9) and ICA (7). Eighty eight % of patients required three or less attempts at recanalization and 71 % achieved TICI 2b or 3. Histopathology demonstrated fibrin rich (5), erythrocytic (2), layered (7), and serpentine (11) thrombi and four were CD 34 positive. Levels of plasma biomarkers were: sTM 2.2±0.4 (&lt;0.6-10.2ng/ml), MPs 101.4±18.4 (1.33-221nM), and sICAM1 160.0±19.8 (&lt;15-406.1ng/ml). Patients with &gt; 3 revascularization attempts had higher levels of sTM (5.5±0.4 vs 1.7±0.2, p&lt;0.0002), sICAM (261.2±79.2 vs. 146.3±20.3, p&lt;0.03), and CD31CT (27.7±0.8 vs 25.5±0.3, p &lt; 0.03). Patients with PH 1 or 2 ICH had higher levels of microparticles than those without ICH or with HI 1 or 2 (203±19 vs 92±19, p&lt;0.05). Patients with cardioembolic stroke had higher sTM (2.8±0.8 vs. 1.3±0.3, p&lt;0.05) and sICAM1 levels (186±32 vs. 115±29, p&lt;0.05) than those with carotid or intracerebral atherosclerosis. Conclusions: ET markers can be detected in the retrieved thrombi and plasma milieu of ELVO patients. ET markers relate to increasing number of attempts at thrombectomy indicating ET disruption. sTM and sICAM are more common in patients with cardioembolic stroke and may serve as thrombus associated markers of AIS mechanism.

Antiplatelet pretreatment and outcomes following mechanical thrombectomy for emergent large vessel occlusion strokes

BackgroundFew data are available regarding the safety and efficacy of antiplatelet (APT) pretreatment in acute ischemic stroke (AIS) patients with emergent large vessel occlusions (ELVO) treated with mechanical thrombectomy (MT)....

Post-thrombectomy management of the ELVO patient: Guidelines from the Society of NeuroInterventional Surgery

Recent trials have proven the benefits of endovascular treatment for patients with stroke from emergent large vessel occlusions (ELVOs).1–5 Optimal management of these patients involves attention to pre-procedural, intra-procedural, and...

Admission hyperglycemia and outcomes in large vessel occlusion strokes treated with mechanical thrombectomy

Background and purposeHigher admission serum glucose levels have been associated with poor outcomes in patients with acute ischemic stroke (AIS) treated with IV thrombolysis. We sought to evaluate the association...

Abstract WP20: Efficacy and Safety of Mechanical Thrombectomy in Emergent Large Vessel Occlusions with Concomitant Cervical Internal Carotid Artery Occlusion

Introduction: Recently, five published major randomized controlled clinical trials have demonstrated that timely mechanical thrombectomy (MT) of acute ischemic strokes (AIS) with emergent large vessel occlusion (ELVO) is safe and improves functional outcomes. However, data evaluating the efficacy and safety of MT in ELVO patients with concomitant cervical internal carotid artery (cICA) occlusion is limited. The purpose of this study is to evaluate efficacy and safety of MT in ELVO patients with concomitant cICA occlusion Methods: We prospectively analyzed consecutive AIS patients with anterior circulation ELVO who underwent stent-retriever or primary aspiration thrombectomy at two tertiary stroke centers. Outcome measures in our study were 3-month mortality and modified ranking scale (mRS), as well as symptomatic intracranial hemorrhage (sICH). Safety and efficacy outcomes were compared between ELVO patients with and without concomitant cICA occlusion. Results: A total of 137 AIS patients had anterior circulation ELVO and underwent MT (age 63 ± 14, 49% male, median NIHSS 17, IQR [13-20]). ELVO patients with concomitant cICA occlusion (n=19) did not differ in terms of rates of sICH (0% versus 11%, p=0.21), complete recanalization (68 % versus 68%, p=1.00), onset to groin puncture time (minutes [IQR] 268 [211-379] versus 225 [165-312], p=0.47), 3-month mortality (35% versus 26 %, p=0.55), and mRS of 0-2 at 3 months (41% versus 45%, p=0.80) when compared with ELVO patients without concomitant cICA occlusion (n=118). Admission NIHSS was higher among ELVO patients with concomitant cICA occlusion (median [IQR], 18 [15-22] versus 16 [12-19], p=0.01), and they tended to have higher groin puncture to recanalization time (minutes [IQR] 74 [42-97] versus 49 [38-78], p=0.09). The ordinal shift analysis did not show any difference in favorable outcomes in two groups in unadjusted analyses or after adjustment for admission NIHSS and groin to recanalization time (common OR=0.78 [95% CI: 0.27-2.29, p=0.66]). Angioplasty was performed in 11 of 19 ELVO patients with concomitant cICA occlusion. Three patients required stent placement. Discussion: Our study indicates that MT can be performed safely and effectively in ELVO patients with concomitant cICA occlusion.

Abstract 130: Is Intravenous Thrombolysis Far From Obsolete in the Era of Endovascular Thrombectomy? A Hint From a Meta-analysis of Randomized Clinical Trials

Background &amp; Purpose: Current AHA recommendations advocate that pretreatment with intravenous thrombolysis (IVT) should first be offered to all eligible acute ischemic stroke (AIS) patients with emergent large vessel occlusion (ELVO) before an endovascular thrombectomy (ET) procedure. Nevertheless, recent single-center observational studies question the utility of IVT pretreatment in ELVO patients eligible for systemic thrombolysis and advocate ET monotherapy. We sought to evaluate the comparative efficacy between ET and bridging therapy (IVT&amp;ET) in AIS due to ELVO. Methods: We performed mixed-effects subgroup analyses, according to IVT pretreatment status of both functional independence [modified Rankin Scale (mRS) of 0-2)] and death/dependency (mRS of 5-6) at 90 days using available RCTs that evaluated the safety and efficacy of ET with stent-retrievers in comparison to standard therapy. We additionally performed an ordinal logistic regression analysis of individual patient data on the distribution of 3-month mRS scores (shift analysis) between the two groups. Results: We identified 7 eligible RCTs including 1764 ELVO patients (53% men), and 108 patients randomized to ET without IVT pretreatment. Patients receiving bridging therapy (BT) had lower rates (p=0.041) of 90-day death/dependency (19%, 95%CI: 14%-25%) compared to patients receiving only ET (31%, 95%CI: 21%-43%; Figure). Similarly, shift-analysis favored a trend for BT over ET in terms of better 90-day functional outcome (common OR=0.78, 95%CI: 0.53-1.10; p=0.155). Conclusion: Our findings indicate that pretreatment with IVT prior ET in ELVO patients may be associated with lower rates of three-month death/dependency and a trend towards more favorable functional outcomes. Until the results from head-to-head RCTs comparing BT to ET monotherapy become available, our findings support AHA guidelines recommending delivery of tPA to appropriate ELVO candidates undergoing ET.

Abstract 33: The Impact Transfer Status, Level of Stroke Center Certification, and Hospital Thrombectomy Volume on the Outcome of Acute Ischemic Stroke Patients with Emergent Large Vessel Occlusion

Introduction: Recent thrombectomy trials for emergent large vessel occlusion (ELVO) have spurred an international debate regarding the best way to get ELVO patients to the right centers quickly. Here we attempt to identify triage features associated with the best patient outcomes. Methods: A large, multi-hospital health system Get With The Guidelines stroke registry was used to identify patients &gt;18 years old who had intra-arterial (IA) treatment of ELVO between January 2012 and June 2016. Primary outcomes were modified Rankin score (mRS) at discharge and discharge disposition. Generalized linear regression models were used to identify which of the variables on the figure’s Y-axis were related to the outcomes. Results: We identified 562 ELVO patients who received IA-treatment. Patients were more likely to have greater disability if they were treated at a PSC (AOR=3.14; p=.004), were a transfer (AOR = 5.18, p=.001), had a higher NIHSS score (AOR = 1.10; p&lt;.001), were older (AOR=1.04; p=.003), or had longer Door to IA times (AOR = 1.01; p=.008). Compared to discharge to home, patients were more likely to be sent to hospice or expire if they were treated at a PSC (AOR=2.28; p=.021), were a transfer (AOR=2.39, p=.047), had a higher NIHSS (AOR=1.19; p&lt;.001), were older (AOR = 1.06; &lt;.001), or had longer Door to IA times (AOR = 1.01; p=.009). Patients were more likely to be sent to a SNF if they if they were a transfer (AOR = 2.70, p=.014), had a higher NIHSS score (AOR=1.13; p&lt;.001), were older (AOR = 1.06; &lt;.001), or had longer Door to IA times (AOR = 1.01; p=.029). Conclusions: Being treated locally rather than transferred, at a comprehensive rather than primary stroke center, and with shorter door to IA times were the strongest drivers of good outcome. Conversely, the annual IA treatment volume was not a driver of outcome.

Abstract TP3: What Hospital Characteristics Drive Faster Thrombectomy For Emergent Large Vessel Occlusion (ELVO)?

Introduction: Recent thrombectomy trials for ELVO have reverberated the importance of speed in reperfusion therapy. Identifying hospital practices and features associated with faster door to thrombectomy times is critical to evolving our hospital systems to effectively deliver this powerful therapy. Methods: A multi-hospital, Get with the Guidelines stroke registry was used to identify AIS patients who received intra-arterial (IA) intervention between January 2012 and May 2016. Transferred patients were excluded since their door to reperfusion times don’t typically include a primary evaluation. Patients were categorized as having door to reperfusion (Door-to-IA) time over 135 minutes or Door-to-IA time below or equal to 135 minutes. A multivariate logistic regression model was used to identify which of the following variables were associated with Door-to-IA times over 135 minutes: age, gender, IV alteplase treatment, admit NIHSS score, patient arrival time to hospital, hospital certification (primary stroke center (PSC) versus comprehensive stroke center (CSC)), hospital annual IA treatment volume, and hospital annual percentage of transfers for thrombectomy. Results: We identified 229 AIS patients from ten hospitals who received IA intervention between January 2012 and May 2016. Of those, 49% (n=113) had Door-to-IA times over 135 minutes and 51% (n=116) had Door-to-IA time below or equal to 135 minutes. Patients with Door-to-IA times over 135 minutes were more likely to be older (adjusted odds ratio (AOR) = 1.02 per year; p=.040), treated at a PSC (AOR = 2.26; p=.028), and treated at a hospital with a higher percentage of transfers (AOR = 1.08 per percentage point; p&lt;.001). IV-alteplase treatment, gender, NIHSS, patients’ arrival time and volume were not significant. Conclusion: Comprehensive stroke centers had shorter Door-to-IA times than Primary Stroke Centers in our system. However, hospital annual IA treatment volume did not impact Door-to-IA and centers with larger transfer volume actually had worse Door-to-IA times for patients evaluated and treated locally. This suggests that high volume centers with a larger volume of transferred patients may have tuned their practices to treating transfers rather than treating local ELVO patients.

Abstract WP49: Performance of CT, CTA, and MRI on Decision to Treat Emergent Large Vessel Occlusion (ELVO) in Patients who Present Greater Than 6 Hours After Stroke Onset

Background and purpose: We compared the value of Alberta Stroke Program Early Computed Tomographic scoring using CT (CT ASPECTS), collateral score on CT angiography (CTA), ASPECTS using diffusion-weighted MRI (DWI ASPECTS), DWI lesion volume, and DWI volume with National Institute of Health Stroke Scale (NIHSS) in determining candidacy of patients who presented &gt;6 hours from stroke onset. Methods: Decision to treat was first determined for each test alone and then with knowledge from other tests. A dismantling design was used to determine the additive effects of each test. Any discrepancy between the first and subsequent decisions to treat, in terms of sensitivity and specificity, is the impact of gained knowledge and was assessed using a generalized mixed-model assuming a binary distribution with PROC GLIMMIX/SAS. Inter-rater reliability was examined using weighted-Kappa. Results: We identified 39 patients between December 1st, 2015 and June 30th 2016. Median time from last-known normal to non-contrast CT was 492 minutes. Median interval between non-contrast CT and CTA was 7 minutes, and between CTA and MRI, 75.5 minutes. For sensitivity, effect of knowledge gained from successive tests was not significant (Table 1; Fig. 1). However, significant gains in specificity were observed from successive tests (63% to 84%; p&lt;.01). In particular, specificity increased by 14% (p=.09), 18% (p=.02), and 12% (p=.07), for DWI ASPECTS, DWI Volume, and DWI Volume+NIHSS, respectively. Inter-rater reliability was between .34-1.0 for each test. Conclusion: CT, CTA and MRI each have the ability to correctly determine ELVO patients who would be candidates for embolectomy. However, identification of poor candidates for endovascular therapy was significantly improved using diffusion-weighted MRI.

Endovascular thrombectomy with or without systemic thrombolysis?

Current recommendations advocate that pretreatment with intravenous thrombolysis (IVT) should first be offered to all eligible patients with emergent large vessel occlusion (ELVO) before an endovascular thrombectomy (ET) procedure. However, there are observational data that question the safety and efficacy of IVT pretreatment in patients with ELVO. We performed a meta-analysis of the included subgroups from ET randomized controlled trials (RCTs) to evaluate the comparative efficacy between direct ET without IVT pretreatment and bridging therapy (IVT and ET) in patients with ELVO. We included a total of seven RCTs, including 1764 patients with ELVO (52.8% men). Patients receiving bridging therapy (IVT followed by ET) had lower rates (p = 0.041) of 90-day death/severe dependency (modified Rankin Scale-score of 5-6; 19.0%, 95% CI: 14.1-25.1%) compared with patients receiving only ET (31.0%, 95% CI: 21.2-42.9%). Moreover, patients receiving IVT and ET had a nonsignificant (p = 0.389) trend towards higher 90-day functional independence rates (51.4%, 95% CI: 42.5-60.1%) compared with patients undergoing only ET (41.7%, 95% CI: 24.1-61.7%). Finally, shift-analysis uncovered a nonsignificant trend towards functional improvement at 90 days for bridging therapy over ET (cOR = 1.28, 95% CI: 0.91-1.89; p = 0.155). It should be noted that patients included in the present meta-analysis were not randomized to receive IVT, and thus the two groups (bridging therapy versus ET monotherapy) may differ in terms of baseline characteristics and, in particular, in terms of onset to groin puncture time and thus the risk of confounding bias cannot be ruled out. Despite the limitations and the risk of confounding bias, our findings contradict the recent notion regarding potential equality between ET and bridging therapy in ELVO patients and suggest that IVT and ET are complementary therapies that should be pursued in a parallel and noncompeting fashion.