Outcomes of Mechanical Thrombectomy for Patients With Stroke Presenting With Low Alberta Stroke Program Early Computed Tomography Score in Early and Late Time Windows

BACKGROUND AND OBJECTIVES

This study aimed to compare outcomes of low Alberta Stroke Program Early Computed Tomography Score (ASPECTS) patients with stroke who underwent mechanical thrombectomy (MT) within 6 hours or 6 to 24 hours after stroke onset.

METHODS

A retrospective cohort study was conducted using data from a large multicenter international registry from 2013 to 2023. Patients with low ASPECTS (2-5) who underwent MT for anterior circulation intracranial large vessel occlusion were included. A propensity matching analysis was conducted for patients presented in the early (<6 hours) vs late (6-24 hours) time window after symptom onset or last known normal.

RESULTS

Among the 10 229 patients who underwent MT, 274 met the inclusion criteria. 122 (44.5%) patients were treated in the late window. Early window patients were older (median age, 74 years [IQR, 63-80] vs 66.5 years [IQR, 54-77]; P < .001), had lower proportion of female patients (40.1% vs 54.1%; P = .029), higher median admission National Institutes of Health Stroke Scale score (20 [IQR, 16-24] vs 19 [IQR, 14-22]; P = .004), and a higher prevalence of atrial fibrillation (46.1% vs 27.3; P = .002). Propensity matching yielded a well-matched cohort of 84 patients in each group. Comparing the matched cohorts showed there was no significant difference in acceptable outcomes at 90 days between the 2 groups (odds ratio = 0.90 [95% CI = 0.47-1.71]; P = .70). However, the rate of symptomatic ICH was significantly higher in the early window group compared with the late window group (odds ratio = 2.44 [95% CI = 1.06-6.02]; P = .04).

CONCLUSION

Among patients with anterior circulation large vessel occlusion and low ASPECTS, MT seems to provide a similar benefit to functional outcome for patients presenting <6 hours or 6 to 24 hours after onset.

Impact of Procedure Time on First Pass Effect in Mechanical Thrombectomy for Anterior Circulation Acute Ischemic Stroke

BACKGROUND AND OBJECTIVES

First pass effect (FPE) is a metric increasingly used to determine the success of mechanical thrombectomy (MT) procedures. However, few studies have investigated whether the duration of the procedure can modify the clinical benefit of FPE. We sought to determine whether FPE after MT for anterior circulation large vessel occlusion acute ischemic stroke is modified by procedural time (PT).

METHODS

A multicenter, international data set was retrospectively analyzed for anterior circulation large vessel occlusion acute ischemic stroke treated by MT who achieved excellent reperfusion (thrombolysis in cerebral infarction 2c/3). The primary outcome was good functional outcome defined by 90-day modified Rankin scale scores of 0-2. The primary study exposure was first pass success (FPS, 1 pass vs ≥2 passes) and the secondary exposure was PT. We fit-adjusted logistic regression models and used marginal effects to assess the interaction between PT (≤30 vs >30 minutes) and FPS, adjusting for potential confounders including time from stroke presentation.

RESULTS

A total of 1310 patients had excellent reperfusion. These patients were divided into 2 cohorts based on PT: ≤30 minutes (777 patients, 59.3%) and >30 minutes (533 patients, 40.7%). Good functional outcome was observed in 658 patients (50.2%). The interaction term between FPS and PT was significant ( P = .018). Individuals with FPS in ≤30 minutes had 11.5% higher adjusted predicted probability of good outcome compared with those who required ≥2 passes (58.2% vs 46.7%, P = .001). However, there was no significant difference in the adjusted predicted probability of good outcome in individuals with PT >30 minutes. This relationship appeared identical in models with PT treated as a continuous variable.

CONCLUSION

FPE is modified by PT, with the added clinical benefit lost in longer procedures greater than 30 minutes. A comprehensive metric for MT procedures, namely, FPE 30 , may better represent the ideal of fast, complete reperfusion with a single pass of a thrombectomy device.

Comparative Outcomes of Mechanical Thrombectomy in Acute Ischemic Stroke Patients with ASPECTS 2-3 vs. 4-5

BACKGROUND

The influence of Alberta Stroke Program Early CT Score (ASPECTS) on outcomes following mechanical thrombectomy (MT) for acute ischemic stroke (AIS) patients with low ASPECTS remains unknown. In this study, we compared the outcomes of AIS patients treated with MT for large vessel occlusion (LVO) categorized by ASPECTS value.

METHODS

We conducted a retrospective analysis involving 305 patients with AIS caused by LVO, defined as the occlusion of the internal carotid artery and/or the M1 segments of the middle cerebral artery, stratified into two groups: ASPECTS 2-3 and 4-5. The primary outcome was favorable outcome defined as a 90-day modified Rankin Scale (mRS) score of 0-3. Secondary outcomes were 90-day mRS 0-2, 90-day mortality, any intracerebral hemorrhage (ICH), and symptomatic ICH (sICH). We performed multivariable logistic regression analysis to evaluate the impact of ASPECTS 2-3 vs. 4-5 on outcomes.

RESULTS

Fifty-nine patients (19.3%) had ASPECTS 2-3 and 246 (80.7%) had ASPECTS 4-5. Favorable outcomes showed no significant difference between the two groups (adjusted odds ratio [aOR]= 1.13, 95% confidence interval [CI]: 0.52-2.41, p=0.80). There were also no significant differences in 90-day mRS 0-2 (aOR= 1.65, 95% CI: 0.66-3.99, p=0.30), 90-day mortality (aOR= 1.14, 95% CI: 0.58-2.20, p=0.70), any ICH (aOR= 0.54, 95% CI: 0.28-1.00, p=0.06), and sICH (aOR= 0.70, 95% CI: 0.27-1.63, p = 0.40) between the groups.

CONCLUSIONS

AIS patients with LVO undergoing MT with ASPECTS 2-3 had similar outcomes compared to ASPECTS 4-5.

Thrombectomy in Stroke Patients With Low Alberta Stroke Program Early Computed Tomography Score: Is Modified Thrombolysis in Cerebral Infarction (mTICI) 2c/3 Superior to mTICI 2b?

BACKGROUND AND PURPOSE

Outcomes following mechanical thrombectomy (MT) are strongly correlated with successful recanalization, traditionally defined as modified Thrombolysis in Cerebral Infarction (mTICI) ≥2b. This retrospective cohort study aimed to compare the outcomes of patients with low Alberta Stroke Program Early Computed Tomography Score (ASPECTS; 2-5) who achieved mTICI 2b versus those who achieved mTICI 2c/3 after MT.

METHODS

This study utilized data from the Stroke Thrombectomy and Aneurysm Registry (STAR), which combined databases from 32 thrombectomy-capable stroke centers between 2013 and 2023. The study included only patients with low ASPECTS who achieved mTICI 2b, 2c, or 3 after MT for internal carotid artery or middle cerebral artery (M1) stroke.

RESULTS

Of the 10,229 patients who underwent MT, 234 met the inclusion criteria. Of those, 98 (41.9%) achieved mTICI 2b, and 136 (58.1%) achieved mTICI 2c/3. There were no significant differences in baseline characteristics between the two groups. The 90-day favorable outcome (modified Rankin Scale score: 0-3) was significantly better in the mTICI 2c/3 group than in the mTICI 2b group (adjusted odds ratio 2.35; 95% confidence interval [CI] 1.18-4.81; P=0.02). Binomial logistic regression revealed that achieving mTICI 2c/3 was significantly associated with higher odds of a favorable 90-day outcome (odds ratio 2.14; 95% CI 1.07-4.41; P=0.04).

CONCLUSION

In patients with low ASPECTS, achieving an mTICI 2c/3 score after MT is associated with a more favorable 90-day outcome. These findings suggest that mTICI 2c/3 is a better target for MT than mTICI 2b in patients with low ASPECTS.

Predictors of Angiographic Outcome After Failed Thrombectomy for Large Vessel Occlusion: Insights from the Stroke Thrombectomy and Aneurysm Registry

BACKGROUND

Mechanical thrombectomy failure (MTF) occurs in approximately 15% of cases.

OBJECTIVE

To investigate factors that predict MTF.

METHODS

This was a retrospective review of prospectively collected data from the Stroke Thrombectomy and Aneurysm Registry. Patients who underwent mechanical thrombectomy (MT) for large vessel occlusion (LVO) were included. Patients were categorized by mechanical thrombectomy success (MTS) (≥mTICI 2b) or MTF (

RESULTS

A total of 6780 patients were included, and 1001 experienced anterior circulation MTF. Patients in the MTF group were older (73 vs 72, P = .044) and had higher poor premorbid modified Rankin Scale (mRS) (10.8% vs 8.4%, P = .017). Onset to puncture time was greater in the MTF group (273 vs 260 min, P = .08). No significant differences were found between the access site, use of balloon guide catheter, frontline technique, or first-pass devices between the MTF and MTS groups. More complications occurred in the MTF group (14% vs 5.8%), including symptomatic intracerebral hemorrhage (9.4% vs 6.1%) and craniectomies (10% vs 2.8%) ( P < .001). On UVA, age, poor pretreatment mRS, increased number of passes, and increased procedure time were associated with MTF. Internal carotid artery, M1, and M2 occlusions had decreased odds of MTF. Poor preprocedure mRS, number of passes, and procedure time remained significant on MVA. A subgroup analysis of posterior circulation LVO revealed that number of passes and total procedure time correlated with increased odds of MTF ( P < .001) while rescue stenting was associated with less odds of MTF (odds ratio 0.20, 95% CI 0.06-0.63). Number of passes remained significant on MVA of posterior circulation occlusion subgroup analysis.

CONCLUSION

Anterior circulation MTF is associated with more complications and worse outcomes. No differences were found between techniques or devises used for the first pass during MT. Rescue intracranial stenting may decrease the likelihood of MTF for posterior circulation MT.

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Key Words Collapse

MESH Headings

• Humans
• Stroke/surgery
• Thrombectomy/methods
• Cerebral Hemorrhage
• Retrospective Studies
• Aneurysm
• Registries
• Treatment Outcome
• Brain Ischemia/therapy

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The effect of occlusion location and technique in mechanical thrombectomy for minor stroke

INTRODUCTION

Endovascular mechanical thrombectomy (MT) is an established treatment for large vessel occlusion strokes with a National Institutes of Health Stroke Scale (NIHSS) score of 6 or higher. Data pertaining to minor strokes, medium, or distal vessel occlusions, and most effective MT technique is limited and controversial.

METHODS

A multicenter retrospective study of all patients treated with MT presenting with NIHSS score of 5 or less at 29 comprehensive stroke centers. The cohort was dichotomized based on location of occlusion (proximal vs. distal) and divided based on MT technique (direct aspiration first-pass technique [ADAPT], stent retriever [SR], and primary combined [PC]). Outcomes at discharge and 90 days were compared between proximal and distal occlusion groups, and across MT techniques.

RESULTS

The cohort included 759 patients, 34% presented with distal occlusion. Distal occlusions were more likely to present with atrial fibrillation (p = 0.008) and receive IV tPA (p = 0.001). Clinical outcomes at discharge and 90 days were comparable between proximal and distal groups. Compared to SR, patients managed with ADAPT were more likely to have a modified Rankin Scale of 0-2 at discharge and at 90 days (p = 0.024 and p = 0.013). Primary combined compared to ADAPT, prior stroke, multiple passes, older age, and longer procedure time were independently associated with worse clinical outcome, while successful recanalization was positively associated with good clinical outcomes.

CONCLUSIONS

Proximal and distal occlusions with low NIHSS have comparable outcomes and safety profiles. While all MT techniques have a similar safety profile, ADAPT was associated with better clinical outcomes at discharge and 90 days.

Evaluation of the Thoracolumbar Injury Classification and Severity (TLICS) Score Over a Two-Year Period at a Level One Trauma Center

Introduction The use of the Thoracolumbar Injury Classification and Severity Score (TLICS) and other classification systems for guiding the management of traumatic spinal injuries remains controversial. TLICS is one of the few classifications that provides treatment recommendations.We sought to analyze intervention modality selection based on the TLICS scoring system. Methods A retrospective review of patients presenting with traumatic thoracolumbar fractures at a level 1 trauma center over a two-year period was performed. Primary endpoints for comparison analysis included visual analog scale (VAS) scores and Cobb angles during follow-up. Results There were 272 patients with thoracolumbar fractures, of whom 212 had TLICS of ≤3, six with TLICS of 4, and 54 with TLICS of ≥5. Of the 272 total patients, 59 were treated via surgery and 213 via non-surgical conservative methods. The VAS scores significantly decreased from presentation to last follow-up in both surgically treated and conservative groups (p<0.0001). This remained consistent in subgroup analyses of TLICS ≤ 3, TLICS = 4, and TLICS ≥ 5 (p<0.0001). Burst fractures treated conservatively had larger fracture Cobb angles versus those treated via surgery at the last follow-up, although this was not significantly associated (p=0.07). The only significant relationship with Cobb angles was in distraction fractures of the TLICS > 4 conservative group, who had significantly lower Cobb angles at the last follow-up than the TLICS > 4 surgical group (p<0.04). The "surgeon's choice" for TLICS = 4 was surgical intervention (4/6 patients, 66.7%). Conclusion Using the TLICS score, thoracolumbar injuries in a level 1 trauma center are more commonly TLICS ≤ 3. For patients with TLICS = 4, the surgeon's choice was most commonly surgical repair. VAS scores decreased over time from presentation between surgically and conservatively managed patients (as well as within-group analyses). The data concerning Cobb angles were more ambiguous, as larger Cobb angles in burst fractures treated conservatively did not show statistically significant differences with surgery.

Recurrence Rates Following Treatment of Spinal Vascular Malformations: A Systematic Review and Meta-Analysis

BACKGROUND

Spinal vascular malformations (SVMs), including arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs), are a varied group of vascular lesions that can be subclassified according to localization, vascular structure, and hemodynamics. Early intervention is necessary to halt progression of disease and minimize irreversible dysfunction. We sought to characterize initial treatment success and recurrence rates following interventional treatment of various types of SVMs.

METHODS

A systematic review and meta-analysis were performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. SVMs were categorized into 4 groups: dural AVFs, perimedullary AVFs, intramedullary AVMs, and extradural-intradural AVMs (e.g., epidural, paraspinal). Initial occlusion, recurrence, and complication rates were compared using random-effects analysis.

RESULTS

There were 112 manuscripts included, with a total of 5626 patients with SVM. For treatment, 2735 patients underwent endovascular embolization, 2854 underwent surgical resection, and 37 underwent stereotactic radiosurgery. The initial treatment success and overall recurrence rates following surgical resection of all SVMs were 89.5% (95% CI: 80.5%-98.5%) and 2.3% (95% CI: 0.9%-3.7%), respectively. Those rates following endovascular embolization were 55.9% (95% CI: 30.3%-81.5%) and 27.7% (95% CI: 11.2%-44.2%), respectively. Higher rates of initial treatment success and lower rates of recurrence with surgery were observed in all subtypes compared to embolization. Overall complication rates were higher after embolization for each of the SVM categories.

CONCLUSIONS

Surgical resection of SVMs provided higher rates of initial complete occlusion and lower rates of recurrence than endovascular techniques. Attaining technical success through obliteration must still be weighed against clinical impact and natural history of the specific vascular malformation.

Abstract WP164: Acute Carotid Stenting Versus Conservative Management For Tandem Carotid Occlusions: Insights From STAR

Introduction: Management of anterior circulation emergent large vessel occlusion with tandem carotid occlusion (TCO) remains a challenge during mechanical thrombectomy (MT). To day, there is no consensus regarding emergent carotid stenting (ECS) in the setting of MT with TCO. We aimed to compare the outcomes of ECS versus conservative management (MT alone) among patients with TCO.

Methods: Data from the Stroke Thrombectomy and Aneurysm Registry between 2010 and 2022 was interrogated. Only patients with concomitant occlusions of cervical carotid and proximal ipsilateral intracranial segments of the ICA or MCA were included in the analyses. We compared baseline, procedural charecteristics, successful reperfusion (mTICI 2b-3), favorable 90-day good outcomes (mRS 0-2), intravenous tPA administration and symptomatic ICH between patients who did or did not undergo ECS. Multivariate regression was performed adjusting for variables of clinical importance. Propensity score matching for IV tPA use was performed to explore its safety with stenting.

Results: Among 9812 thrombectomy patients, 688 patients had TCO; 132 underwent emergent stenting and 444 had MT alone. Patients who did not undergo ECS had a higher prevalence of atrial fibrillation (33.9% Vs 9.2%, P<.001), higher admission NIHSS scores (18 Vs 14, P<.001), shorter time from symptom onset to puncture (275 minutes Vs 333 minutes, P=0.029), and were predominantly women (59.2% Vs 33.6%, P<0.001).Patients with stenting had lower mortality rates ( 17.5% Vs 29.6%, P=0.009), and higher rates of successful reperfusion (83% Vs 95%, P=0.001). No difference in mRS 0-2 (37.5% Vs 30.4%, P=0.178) or sICH were seen (11.1% Vs 15.4%, P=0.219). Propensity score matching analysis (n=129 in each group) demonstrated better rates of reperfusion (94.8 Vs 84.4%, P=0.011) in the stenting group. Advanced age, higher admission NIHSS and lower ASPECT scores were associated with worse clinical outcomes.

Conclusion: ECS during MT for TCO appears to be safe and is associated with better clinical and angiographic outcomes compared to conservative management.

Abstract 48: Outcomes And Risk Of Hemorrhagic Transformation Following Mechanical Thrombectomy In Primary Distal Posterior Cerebral Artery Occlusions-subgroup Analysis From STAR

Background: While mechanical thrombectomy (MT) has become the standard of care for acute stroke patients presenting with large vessel occlusion (LVO) and salvageable brain tissue, limited data is currently available regarding the benefits of MT in patents with medium vessel occlusions (MeVO) especially in the posterior circulation (P2 occlusions).

Methods: We used the Stroke Thrombectomy and Aneurysm registry (STAR) which included data from 35 stroke centers in North America, Europe, Asia, and South America. We included patients who presented with MeVO in the M2, M3 or P2 segments and underwent MT. We used a Generalized Linear Model to assess the relationship between location of occlusion and outcomes.

Results: 9812 patients were included in STAR at the time of this analysis; 43 underwent MT for P2 occlusion, 130 underwent MT for M3 occlusion; and 1273 underwent MT for M2 occlusion. There was no difference in age, sex, race, rate of IV-tPA and stroke severity between patients in all 3 groups (Table 1). There was a trend toward lower rate of atrial fibrillation in patients with P2 and M3 occlusions. Patients with P2 occlusions were less likely to achieve successful recanalization (modified treatment in cerebral infarction score≥2b); intraarterial thrombolysis was used less in P2 occlusions (4.7% compared to 16.2% in M3 occlusions and 10.1% in M2 occlusions). However, there was no difference in the rate of successful first pass. On multivariable analysis, P2 occlusions were not associated with hemorrhagic transformation (OR 2.0, 95% CI 0.7-5.7, P 0.186), 90-day mortality (OR 0.5, 95% CI 0.2-1.4, P 0.183), or 90-day favorable outcome (OR 2.0, 95% CI 0.9-4.4, P 0.084).

Conclusions: In this multicenter study, there was no significant difference in safety and efficacy of MT in patients with MeVOs in posterior circulation (P2 occlusions) compared to M2 and M3 occlusions. Improved techniques for successful recanalization are needed for posterior circulation MeVOs.

Abstract 98: The Impact Of Aspiration Catheter Size On Thrombectomy Outcomes Using Adapt Technique-analysis From The STAR Registry

Introductions: Clinical trials have shown that aspiration thrombectomy is as safe and effective as stent-retriever thrombectomy. Multiple improvements have been made to the aspiration technique over the last few years. In this study, we aim to assess the effect of aspiration catheter bore size on the outcomes of A direct aspiration first pass technique (ADAPT) thrombectomy.

Methods: We included patients who underwent ADAPT thrombectomy for M1 or internal carotid artery terminus (ICA-T) occlusions in the Stroke Thrombectomy and Aneurysm (STAR) database. Patients included between July 2016 and July 2022. We compared baseline characteristics, procedural metrics and outcomes between patients who underwent thrombectomy using small bore (0.035”-0.060”), medium bore (0.062”-0.068”) and large bore (0.070”-0.074”) catheters.

Results: A total of 1158 patients were included; 576 (49.7%) females, 645 (70%) White, and 464 (40.6%) received IV-tPA. No difference was noticed in age, sex, and vascular risk factors between the 3 different groups. There was higher rate of IV-tPA in the small-bore catheter group (48.8%) compared to the medium and large bore catheter groups (38.4% and 36.7%, respectively) (P=0.03). Procedure duration was shorter when using medium (20 min) and large (18 min) compared to small bore catheters (30 min) (P=0.01). Both medium and large bore catheters were associated with higher rate of successful recanalization (88.9% and 87.9%, respectively) compared to small bore catheters (81.6%) (P=0.010). However, the difference in successful recanalization or procedure duration between medium and large bore catheters was not significant. No difference was noted in the rate of symptomatic hemorrhagic transformation (sICH) (4.7%, 5.3%, and 7.1%; P=0.345), 90-day favorable outcome (modified Rankin Scale 0-2) (41.8%, 39.3%, 40.8%; P=0.766) or 90-day mortality (18.1%, 23.5%, 24.4%; P=0.111) between the groups.

Conclusions: Higher rate of successful recanalization and shorter procedure duration were observed when using medium and large bore aspiration catheters compared with small bore catheters in ADAPT technique. However, these procedural benefits were not observed when comparing large bore to medium bore catheters.

Abstract TP154: Outcomes Of Acute Carotid Stenting With Or Without Intravenous Thrombolysis Among Patients With Acute Tandem Occlusion: Insights From STAR

Introduction: Emergency carotid artery stenting during mechanical thrombectomy has emerged as an effective emergent treatment for tandem carotid occlusions. Nevertheless, scarce evidence is available about the safety of this procedure in patients who received intravenous tPA before thrombectomy. Herein, we investigate the safety of acute carotid stenting among patients who received intravenous tPA in a large international multicenter registry.

Methods: Patients from the Stroke Thrombectomy and Aneurysm Registry between 2010 and 2022 were analyzed. Only patients with concomitant occlusions of cervical carotid and proximal ipsilateral intracranial segments of the internal carotid or middle cerebral artery were included in the final analyses. Patients were divided into two groups, depending on tPA administration. The primary outcome was 90-day good clinical outcome (mRS 0-2), and the primary safety outcome was symptomatic intracranial hemorrhage. Univariate and multivariate regressions were performed adjusting for variables of clinical importance.

Results: Among 9812 with acute ischemic stroke in the registry, 132 patients had acute tandem occlusion and underwent carotid stenting; of those, 60 patients received IV tPA. Compared to non-intravenous thrombolytics, patients with IV tPA had a higher male prevalence (78.3% Vs 54.4%, P=0.005) and better ASPECT scores (9 Vs 8, P=0.022) with a shorter time from onset to puncture (241 Vs 672 minutes, P<0.001). There was no difference in rates of successful revascularization (94% Vs 95.5%, P=NS), good clinical outcome (50.8% Vs 61.4%, P=NS), symptomatic intracranial hemorrhage (15.3% Vs 14.5%, P=NS) or procedural complications (15% Vs 11.6%, P=NS) between the tPA and non-tPA groups.

Conclusion: The use of IV tPA did not affect the safety or efficacy of emergent carotid stenting in the setting of acute tandem occlusion.

Predictors and outcomes of first pass efficacy in posterior circulation strokes: Insights from STAR collaboration

Background: First-pass efficacy (FPE) has been established as an important predictor of favorable functional outcomes after endovascular thrombectomy (ET) in anterior circulation strokes. In this retrospective cohort study, we investigate predictors and clinical outcomes of FPE in posterior circulation strokes (pcAIS). Methods: The Stroke Thrombectomy and Aneurysm Registry database was used to identify pcAIS patients who achieved FPE. Their baseline characteristics and outcomes were compared with the non-FPE group. The primary outcome was a 90-day modified Rankin Scale (mRS) of 0-3. Univariate (UVA) and multivariate (MVA) analyses were done to evaluate predictors of FPE. Safety outcomes included distal emboli, vessel rupture, symptomatic intracranial hemorrhage, and mortality. Results: Of 359 patients, 179 (50%) achieved FPE. Clot burden, occlusion site, and ET technique-related variables were similar between the two groups except for shorter procedure time with FPE. The primary outcome was significantly better with FPE (56.4% vs. 32.8%, p < 0.001). Complications were similar except for a higher rate of distal emboli in non-FPE group (11.1% vs. 3.2%, p = 0.032). Atrial fibrillation (Afib) had increased odds (aOR: 2.06, 95% CI; 1.24, 3.4, p = 0.005) and prior ischemic stroke had decreased odds (aOR: 0.524, 95% CI; 0.28, 0.97, p = 0.04) of FPE. Afib was the only independent predictor of FPE on MVA (1.94, 95% CI; 1.1, 3.43, p = 0.022). Conclusions: Higher rate of FPE in Afib-related pcAIS could possibly be explained by the differences in clot composition and degree of in-situ atherosclerotic disease burden. Future studies are warranted to explore the relationship of clot composition with ET outcomes.

Multicenter investigation of technical and clinical outcomes after thrombectomy for Proximal Medium Vessel Occlusion (pMeVO) by frontline technique

BACKGROUND

Endovascular thrombectomy(EVT) is the standard of care for large vessel occlusion(LVO) stroke. Data on technical and clinical outcome in proximal medium vessel occlusions(pMeVOs) comparing frontline techniques remain limited.

METHODS

We report an international multicenter retrospective study of patients undergoing EVT for stroke at 32 centers between 2015-2021. Patients were divided into LVOs(ICA/M1/Vertebrobasilar) or pMeVOs(M2/A1/P1) and categorized by thrombectomy technique. Primary outcome was 90-day good functional outcome(mRS ≤ 2). Multivariate logistic regressions were used to evaluate the impact of technical variables on clinical outcomes. Propensity score matching was used to compare outcome in patients with pMeVO treated with aspiration versus stent-retriever.

RESULTS

In the cohort of 5977 LVO and 1287 pMeVO patients, pMeVO did not independently predict good-outcome(p  =  0.55). In pMeVO patients, successful recanalization irrespective of frontline technique(aOR = 3.2,p < 0.05), procedure time ≤ 1-h(aOR = 2.2,p < 0.05), and thrombectomy attempts ≤ 4(aOR =  2.8,p < 0.05) were independent predictors of good-outcomes.In a propensity-matched cohort of aspiration versus stent-retriever pMeVO patients, there was no difference in good-outcomes. The rates of hemorrhage were higher(9%vs.4%,p < 0.01) and procedure time longer(51-min vs. 33-min,p < 0.01) with stent-retriever, while the number of attempts was higher with aspiration(2.5vs.2,p < 0.01). Rates of hemorrhage and good-outcome showed an exponential relationship to procedural metrics, and were more dependent on time in the aspiration group compared to attempts in the stent-retriever group.

CONCLUSIONS

Clinical outcomes following EVT for pMeVO are comparable to those in LVOs. The golden hour or 3-pass rules in LVO thrombectomy still apply to pMeVO thrombectomy. Different techniques may exhibit different futility metrics; SR thrombectomy was more influenced by attempts whereas aspiration was more dependent on procedure time.

Prognostic significance of age within the adolescent and young adult acute ischemic stroke population after mechanical thrombectomy: insights from STAR

OBJECTIVE

Although younger adults have been shown to have better functional outcomes after mechanical thrombectomy (MT) for acute ischemic stroke (AIS), the significance of this relationship in the adolescent and young adult (AYA) population is not well defined given its undefined rarity. Correspondingly, the goal of this study was to determine the prognostic significance of age in this specific demographic following MT for large-vessel occlusions.

METHODS

A prospectively maintained international multi-institutional database, STAR (Stroke Thrombectomy and Aneurysm Registry), was reviewed for all patients aged 12-18 (adolescent) and 19-25 (young adult) years. Parameters were compared using chi-square and t-test analyses, and associations were interrogated using regression analyses.

RESULTS

Of 7192 patients in the registry, 41 (0.6%) satisfied all criteria, with a mean age of 19.7 ± 3.3 years. The majority were male (59%) and young adults (61%) versus adolescents (39%). The median prestroke modified Rankin Scale (mRS) score was 0 (range 0-2). Strokes were most common in the anterior circulation (88%), with the middle cerebral artery being the most common vessel (59%). The mean onset-to-groin puncture and groin puncture-to-reperfusion times were 327 ± 229 and 52 ± 42 minutes, respectively. The mean number of passes was 2.2 ± 1.2, with 61% of the cohort achieving successful reperfusion. There were only 3 (7%) cases of reocclusion. The median mRS score at 90 days was 2 (range 0-6). Between the adolescent and young adult subgroups, the median mRS score at last follow-up was statistically lower in the adolescent subgroup (1 vs 2, p = 0.03), and older age was significantly associated with a higher mRS at 90 days (coefficient 0.33, p < 0.01).

CONCLUSIONS

Although rare, MT for AIS in the AYA demographic is both safe and effective. Even within this relatively young demographic, age remains significantly associated with improved functional outcomes. The implication of age-dependent stroke outcomes after MT within the AYA demographic needs greater validation to develop effective age-specific protocols for long-term care across both pediatric and adult centers.

Outcomes of Mechanical Thrombectomy for Patients With Stroke Presenting With Low Alberta Stroke Program Early Computed Tomography Score in the Early and Extended Window

IMPORTANCE

Limited data are available about the outcomes of mechanical thrombectomy (MT) for real-world patients with stroke presenting with a large core infarct.

OBJECTIVE

To investigate the safety and effectiveness of MT for patients with large vessel occlusion and an Alberta Stroke Program Early Computed Tomography Score (ASPECTS) of 2 to 5.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used data from the Stroke Thrombectomy and Aneurysm Registry (STAR), which combines the prospectively maintained databases of 28 thrombectomy-capable stroke centers in the US, Europe, and Asia. The study included 2345 patients presenting with an occlusion in the internal carotid artery or M1 segment of the middle cerebral artery from January 1, 2016, to December 31, 2020. Patients were followed up for 90 days after intervention. The ASPECTS is a 10-point scoring system based on the extent of early ischemic changes on the baseline noncontrasted computed tomography scan, with a score of 10 indicating normal and a score of 0 indicating ischemic changes in all of the regions included in the score.

EXPOSURE

All patients underwent MT in one of the included centers.

MAIN OUTCOMES AND MEASURES

A multivariable regression model was used to assess factors associated with a favorable 90-day outcome (modified Rankin Scale score of 0-2), including interaction terms between an ASPECTS of 2 to 5 and receiving MT in the extended window (6-24 hours from symptom onset).

RESULTS

A total of 2345 patients who underwent MT were included (1175 women [50.1%]; median age, 72 years [IQR, 60-80 years]; 2132 patients [90.9%] had an ASPECTS of ≥6, and 213 patients [9.1%] had an ASPECTS of 2-5). At 90 days, 47 of the 213 patients (22.1%) with an ASPECTS of 2 to 5 had a modified Rankin Scale score of 0 to 2 (25.6% [45 of 176] of patients who underwent successful recanalization [modified Thrombolysis in Cerebral Ischemia score ≥2B] vs 5.4% [2 of 37] of patients who underwent unsuccessful recanalization; P = .007). Having a low ASPECTS (odds ratio, 0.60; 95% CI, 0.38-0.85; P = .002) and presenting in the extended window (odds ratio, 0.69; 95% CI, 0.55-0.88; P = .001) were associated with worse 90-day outcome after controlling for potential confounders, without significant interaction between these 2 factors (P = .64).

CONCLUSIONS AND RELEVANCE

In this cohort study, more than 1 in 5 patients presenting with an ASPECTS of 2 to 5 achieved 90-day functional independence after MT. A favorable outcome was nearly 5 times more likely for patients with low ASPECTS who had successful recanalization. The association of a low ASPECTS with 90-day outcomes did not differ for patients presenting in the early vs extended MT window.

A Randomized Controlled Trial of Local Delivery of a Rho Inhibitor (VX-210) in Patients with Acute Traumatic Cervical Spinal Cord Injury

Acute traumatic spinal cord injury (SCI) can result in severe, lifelong neurological deficits. After SCI, Rho activation contributes to collapse of axonal growth cones, failure of axonal regeneration, and neuronal loss. This randomized, double-blind, placebo-controlled phase 2b/3 study evaluated the efficacy and safety of Rho inhibitor VX-210 (9 mg) in patients after acute traumatic cervical SCI. The study enrolled patients 14-75 years of age with acute traumatic cervical SCIs, C4-C7 (motor level) on each side, and American Spinal Injury Association Impairment Scale (AIS) Grade A or B who had spinal decompression/stabilization surgery commencing within 72 h after injury. Patients were randomized 1:1 with stratification by age (<30 vs. ≥30 years) and AIS grade (A vs. B with sacral pinprick preservation vs. B without sacral pinprick preservation). A single dose of VX-210 or placebo in fibrin sealant was administered topically onto the dura over the site of injury during decompression/stabilization surgery. Patients were evaluated for medical, neurological, and functional changes, and serum was collected for pharmacokinetics and immunological analyses. Patients were followed up for up to 12 months after treatment. A planned interim efficacy-based futility analysis was conducted after ∼33% of patients were enrolled. The pre-defined futility stopping rule was met, and the study was therefore ended prematurely. In the final analysis, the primary efficacy end-point was not met, with no statistically significant difference in change from baseline in upper-extremity motor score at 6 months after treatment between the VX-210 (9-mg) and placebo groups. This work opens the door to further improvements in the design and conduct of clinical trials in acute SCI.

Outcomes of Rescue Endovascular Treatment of Emergent Large Vessel Occlusion in Patients With Underlying Intracranial Atherosclerosis: Insights From STAR

Background

Some emergent large vessel occlusions (ELVOs) are refractory to reperfusion because of underlying intracranial atherosclerosis (ICAS), often requiring rescue therapy (RT) with balloon angioplasty, stenting, or both. In this study, we investigate the safety, efficacy, and long‐term outcomes of RT in the setting of mechanical thrombectomy for ICAS‐related ELVO.

Methods and Results

We queried the databases of 10 thrombectomy‐capable centers in North America and Europe included in STAR (Stroke Thrombectomy and Aneurysm Registry). Patients with ELVO who underwent ICAS‐related RT were included. A matched sample was produced for variables of age, admission National Institute of Health Stroke Scale, Alberta Stroke Program Early CT Score, onset to groin puncture time, occlusion site, and final recanalization. Out of 3025 patients with MT, 182 (6%) patients required RT because of underlying ICAS. Balloon angioplasty was performed on 122 patients, and 117 patients had intracranial stenting. In the matched analysis, 141 patients who received RT matched to a similar number of controls. The number of thrombectomy passes was higher (3 versus 1, P<0.001), and procedural time was longer in the RT group (52 minutes versus 36 minutes, P=0.004). There was a higher rate of symptomatic hemorrhagic transformation in the RT group (7.8% versus 4.3%, P=0.211), however, the difference was not significant. There was no difference in 90‐day modified Rankin scale of 0 to 2 (44% versus 47.5%, P=0.543) between patients in the RT and control groups.

Conclusions

In patients with ELVO with underlying ICAS requiring RT, despite longer procedure time and a more thrombectomy passes, the 90 days favorable outcomes were comparable with patients with embolic ELVO.

Abstract P504: Outcomes and Predictors of Successful First Pass in MCA Occlusions Using ADAPT Thrombectomy Technique - Insights From STAR

Introduction: Successful first pass (SFP) has been identified as a key benchmark of the success of mechanical thrombectomy (MT). However, studies that evaluate the predictors and outcomes of SFP using ADAPT (A Direct Aspiration first Pass Technique) are limied by the small number of patients or single center design.

Methods: We used data from the prospectively collected data from 28 stroke centers that are included in the Stroke Thrombectomy and Aneurysm Registry (STAR). Patients with middle cerebral artery (MCA) occlusions at the level of M1 or M2 segments were included. SFP was defined by achieving modified Thrombolysis in Cerebral Infarction (mTICI) score≥2b with a single aspiration attempt. A multivariable logistic regression analysis was used to assess the predictors of SFP and evaluate the relationship between SFP and favorable 90-day outcome (90-day modified Rankin scale ≤2).

Results: Out of 6123 patients included in STAR, 1002 (16.4%) underwent MT of M1 or M2 occlusion using ADAPT technique. SFP was achieved in 390 (38.9%) patients. SFP patients were older (72 vs. 69, P=0.007), had higher Alberta Stroke Program Early CT Score (ASPECTS) on presentation (9 vs. 8, P=0.018) (Table 1). On multivariable analysis, neither age (aOR 1.006, 95% CI 0.996-1.016, P=0.252) nor ASPECTS (aOR 1.055, 95% CI 0.976-1.141, P=0.179) were independent predictor of SFP. Importantly, SFP was independently associated with favorable 90-day outcome (aOR 2.769, 95% CI 1.988-3.858, P<0.001) after controlling for age, sex, ASPECTS, history of atrial fibrillation, NIHSS on presentation, onset to groin time and IV-tPA.

Conclusion: In this cohort of patients with M1 or M2 occlsuion undergoing MT using ADAPT technique, patients who had SFP were older and had better ASPECTS. However, both age and ASPECTS were not independently associated with SFP. Also, patients who had SFP were almost 3 times more likely to achieve favorable 90-day outcome.

Abstract P11: Clinical Utility of Aspects in Late Window Stroke Thrombectomy Patients: Insights From Star

Introduction: Recent trials have proven safety and efficacy of mechanical thrombectomy for patients presenting with emergent large vessel occlusion beyond 6 hours of symptom onset. While evidence supports using baseline CT scan to evaluate the candidacy for mechanical thrombectomy for patients presenting in the early window, late window trials have used advanced imaging such as CT and MR perfusion. We aim to assess outcomes of MT stratified by admission Alberta Stroke Program Early CT Score (ASPECTS).

Methods: We used data from the prospectively maintained registries of 28 stroke centers in the Stroke Thrombectomy and Aneurysm (STAR) collaboration. Demographics, comorbidities, LVO site, ASPECTS, MT technique, radiographic and clinical outcome data were collected. Patients with M1 or ICA occlusion were included in these analyses. Multivariable analysis was performed using a generalized linear model with logit link to assess for variables associated with favorable outcomes.

Results: 3356 patients in the STAR database were reviewed and 347 (10.3%) of those underwent MT in the late window (table). Median age was 69, 189 (54.5%) were female, and 181 (52.2%) were white. 295 patients ASPECTS ≥6. In this group, 200 (68.8%) had M1 occlusion, and the remaining had ICA occlusion. Aspiration thrombectomy was used in 139 (47.1%) of patients. Successful reperfusion was achieved (mTICI≥2b) in 264 (76.1%). sICH was observed in 15 (5.1%). Excellent functional outcome (mRS 0-2) was observed in 124 (42%) patients. ASPECTS score was independently associated with favorable outcomes (aOR 1.2, 95% CI 1.1-1.4, P=0.006).

Conclusion: Excellent outcomes are observed in patients with good ASPECT score presenting in the late window irrespective of perfusion criteria. Admission CT scan could be used to triage patients presenting with emergent large vessel occlusion beyond 6 hours of symptom onset.

Abstract P6: Impact of Ethnicity on the Outcomes of Mechanical Thrombectomy- Insights From Star

Introduction: Previous studies have reported that Hispanic stroke patients have limited access to mechanical thrombectomy (MT) compared to other ethnic groups. This has resulted in worse stroke outcomes in this group. However, limited data is available about the outcomes of MT in Hispanic patients.

Methods: We used data from the Stroke Thrombectomy and Aneurysm Registry (STAR) that combined the prospectively maintained databases of 28 thrombectomy-capable stroke centers in the US, Europe, and Asia. Consecutive patients who underwent MT were included in these analyses and patients were divided into 2 groups (Hispanics vs. non-Hispanics). Baseline features, time from symptom onset, thrombolysis receipt, final thrombolysis in cerebral infarction (TICI) score, symptomatic hemorrhage, and 90-day functional outcomes (measured by modified Rankin scale-mRS) were compared between Hispanic and non-Hispanics patients. A generalized linear model with logit link was used to assess the relationship between ethnicity and favorable outcomes at 90-day (mRS 0-2) controlling for confounders.

Results: We included 2015 patients in these analyses. Of those, 285 (14.1%) were Hispanic. As shown in table 1, Hispanic patients were older (72 vs. 70, p=0.007), more likely to have diabetes (41.1% vs. 26.5%, p<0.001), and more likely to have hypertension (81.8% vs. 73.7%, p=0.004). Importantly, Hispanics had a shorter procedure duration with a similar rate of successful recanalization (TICI≥2B). On multivariable analysis, Hispanic ethnicity was associated with a lower probability of favorable 90-day outcome (aOR 0.659, 95% CI 0.494-0.879, P=0.005) after controlling for age, stroke risk factors and location of occlusion.

Conclusion: Hispanic patients receiving MT have higher rate of stroke risk factors including diabetes and hypertension. Moreover, Hispanic ethnicity was independently associated with lower probability of favorable 90-day outcome.

Abstract P500: Outcomes of Mechanical Thrombectomy in Patients With Low Aspects: Insights From Star

Introduction: Patients with poor baseline images were excluded from most clinical trials so the data about whether these patients could benefit from MT remains unknown. In this study, we aim to investigate the safety and efficacy of MT in patients with large vessel occlusion (LVO) and large core infarct (LCI).

Methods: The Stroke Thrombectomy and Aneurysm Registry (STAR) was interrogated. We included thrombectomy patients presenting with LVO within 24 hours and with a LCI as defined by Alberta Stroke Program Early CT Score (ASPECTS) < 6. Patients presenting within 6 hours of last known normal (LKN) were considered in the early window and patients presenting after 6 hours were considered in the late window. 90-day outcomes were assessed. We used a logistic regression model to assess the factors associated with good 90-day outcome in patients in the early and late windows.

Results: 144 patients were included in this study (table). Median age was 69 and 92 (64%) patients were treated in the early MT window. ICA was the most common site of occlusion (48.6%) and ADAPT was used in 34.7%. Admission NIHSS was 17.5. Successful recanalization (TICI>2b) was achieved in 84.7% and median procedure time was 54 minutes. sICH hemorrhage was observed in 22 (15.3%). Median mRS was 4 at 90 days. Favorable outcome was observed in 41 patients (28.5%) and mortality occurred in in 59 (41%). There was no difference in 90-day functional outcome between patients in early and late windows. In patients presenting in the early window, age (aOR=0.905, p=0.0002) and baseline NIHSS (aOR=0.909, p=0.0423) were independently associated with 90-day outcome. In patients presenting in the late window, only age (aOR=0.934, p=0.0069) was independently associated with good outcome.

Conclusion: More than one in four patients presenting with ASPECTS<6 may achieve functional independence at 90-day following MT. Patient age remains the main predictor of 90-day outcome in patients with low ASPECTS in both late and early windows.

Abstract P20: Bridging Therapy Increases Hemorrhagic Complications Without Improving Functional Outcomes in Atrial Fibrillation Associated Stroke

* on behalf of the Stroke Thrombectomy and Aneurysm Registry (STAR) Collaborators

Introduction: Intravenous thrombolysis complications are enriched in AF associated stroke, as these patients have worse functional outcomes, less effective recanalization, and increased rates of hemorrhagic complications. These data suggest that AF patients may be at particularly high risk for complications of bridging therapy for large vessel occlusions treated with mechanical thrombectomy (MT). Here we determine whether clinical outcomes differ in AF associated stroke treated with MT and bridging therapy.

Methods: We performed a retrospective cohort study of the Stroke and Aneurysm Registry (STAR) from January 2015 to December 2018 and identified 4,169 patients who underwent MT for an anterior circulation stroke, 1,517 (36.4 %) of which had comorbid AF. Prospectively defined baseline characteristics and clinical outcomes were compared.

Results: Hemorrhagic complications after MT were similar in patients with or without AF. In patients without AF, bridging therapy improved 90-day outcomes (aOR 1.32, 1.02-1.74, p<0.05) without increasing hemorrhagic complications. In patients with AF, bridging therapy independently predicted hemorrhagic complications in AF patients (aOR 2.08, 1.06-4.06, p<0.033) without improving functional outcomes.

Conclusions: Bridging therapy in AF patients undergoing thrombectomy independently increased the odds of intracranial hemorrhage and did not improve functional outcomes. AF patients may represent a high-risk subgroup for thrombolytic complications. Randomized trials are warranted to determine whether patients with AF associated stroke may benefit by deferring bridging therapy at thrombectomy-capable centers.

Abstract P479: A Tale of Two Clots: A Multicenter Study on Multiple Territory Thrombectomy

Introduction: The benefit of thrombectomy for large vessel occlusion (LVO) is well proven. There is minimal data on concurrent thrombectomy for multi-territory occlusions.

Methods: We reviewed the STAR registry from 2015-8 for patients treated with either right and left sided thrombectomy or anterior and posterior circulation thrombectomy at 15 comprehensive stroke centers.

Results: There were 4966 patients in the study period who had completed outcome data and LVO thrombectomy. 38 (0.8%) underwent endovascular thrombectomy for multi-territory occlusions. 26% had bilateral occlusions and 74% had anterior and posterior circulation occlusions. Among the 38, 50% were female, 49% were white, and 91% had a prestroke mRS<3. 95% had an ASPECT score of >6 and 55% received iv t-pa. 83% of patients had successful recanalization (TICI 2B/3) for both territories. The overall complication rate was 15%. 5% of patients had sICH or PH2. 26% of patients had a 90day mRS<2. When controlling for admission NIHSS, baseline mRS, age, comorbidities, and ASPECT in logistic regression analysis, multiple territory compared to single territory did not predict increased risk of sICH (p=0.73, 95%CI: 0.2-3.3), rate of TICI2B/3 (OR for TICI2B+: 0.93, p=0.88, CI: 0.38 - 2.3), or worse outcome (OR for good outcome: 0.6, p=.212, CI: 0.3-1.3). On linear regression analysis for attempts and procedure time, multiple territory thrombectomy required significantly higher number of attempts (Coefficient +1.8, p=0.001) without a significantly longer procedure time (Coefficient = +10, p=0.244).

Conclusion: With similar selection to single territory LVOs, good outcome can be achieved in multi-territory infarction with reasonable procedure time and no additional risk of hemorrhage or poor outcome.

Abstract WP32: Introducing STAR: A Multicenter International Collaborative Registry of Real-World Outcomes After Mechanical Thrombectomy for Ischemic Stroke

Introduction: Mechanical thrombectomy (MT) for acute stroke is the current standard of care treatment. Level 1 evidence for efficacy of thrombectomy has been established in multiple randomized controlled trials on selective patient populations; however, the high effect size of MT had led multiple centers in the US and globally to expand their patient selection to include populations that were not studied in major trials. To provide ongoing data on MT outcomes in different patient populations from the real-world, we have initiated an international multicenter initiative, STAR (Stroke Thrombectomy and Aneurysm Registry).

Methods: STAR is a multicenter and international platform to curate patient outcome data after MT for acute ischemic stroke at comprehensive stroke centers. STAR includes all patients who underwent MT for acute ischemic stroke irrespective of age, time from onset, ASPECT score, and NIHSS. Patients were curated from 01/2015 to date and is prospectively maintained. Patient charts are reviewed for demographics, baseline functioning, and admission deficits. Procedure notes are reviewed for technical variables and technical outcomes. Clinical outcomes were collected at 90-day follow-up by stroke neurologist.

Results: A total of 24 centers globally have enrolled in STAR. By December 2018, the total number of enrolled and verified patients in STAR was 3,850 (mean age 69±14, 51% females). Anterior circulation strokes were treated in 89% of cases, average NIHSS on admission was 15.5±7, and 73% had pre-stroke mRS below 2. Around 51% of patients received IV-tPA. Mechanical thrombectomy was performed using aspiration (45%), stent retriever (28%), primary combined approach (24%) or intracranial stenting (3%). Successful recanalization was achieved in 84% of cases, the rate of favorable outcome (mRS 0-2) was 41%, and mortality was 25%. Complication rate was 6% and rate of symptomatic post-procedural hemorrhage was 6%.

Conclusions: STAR represent a large real-world international registry for outcomes after MT, and constitutes a statistically robust platform to study real-world practice outcome in patient sub-populations that are under-represented in randomized trials.

Link: https://medicine.musc.edu/departments/neurosurgery/star

Abstract 150: Multicenter Validation of SPOT, an Artificial Intelligence Based Tool, to Optimize Selection of Elderly Stroke Patients for Mechanical Thrombectomy - Insights From the STAR Collaboration

Introduction: Mechanical thrombectomy for acute ischemic stroke (AIS) is the current standard of care based on level 1 evidence from multiple randomized controlled trials. Recently, real-world indications for mechanical thrombectomy (MT) has extended beyond the inclusion criteria used in the majority of trials including elderly patients. We have recently developed a machine-learning based tool, SPOT, to optimize selection of elderly patients for MT based on single-center data. Here, we use a large cohort of international multicenter patients who underwent MT for AIS to externally validate SPOT.

Methods: Patients who underwent MT for AIS at 12 comprehensive stroke centers in the US and Europe between 01/2013 and 12/2018 were reviewed. Patients age 80 years or older were included for validation of SPOT. SPOT is designed based on a combination of decision trees and linear regression models to provide binary output of predicted good (mRS 0-2) or poor outcome (mRS 3-6) after MT. SPOT uses admission variables: age, gender, comorbidities, admission NIHSS, baseline mRS score, ASPECT score and whether IV-tPA was administered. Predicted outcome was compared to actual outcome recorded at 90-days after treatment. A receiver operating characteristic curve was used to evaluate the accuracy of SPOT, and the negative predictive value was computed. The rate of post-procedural hemorrhage and mortality were compared between patients predicted by SPOT to have good versus poor outcome.

Results: A total of 3,228 patients underwent MT for AIS during the study duration, of which 647 patients were at least 80 years of age or older and were included in the study. The average age was 85±5 years, and 65% were females. The median mRS score at 90 days was 4, and 21.3% had a good outcome (mRS 0-2). Of patients predicted by SPOT to have a poor outcome, 90% had a poor outcome. The area under the ROC curve was 0.7. The mortality rate in patients predicted by SPOT to have poor outcome had twice higher mortality than those predicted to have good outcome (55% vs 27%, p<0.001).

Conclusions: Based on multicenter validation, SPOT presents a clinical decision in aid in assisting for exclusion of elderly patients unlikely to benefit from MT for AIS with a 90% negative predictive value.

Abstract WP2: Long-Term Functional Outcomes Following Mechanical Thrombectomy Stratified by Race- Insights From the STAR Collaboration

Introduction: Previous research reported higher prevalence of vascular risk factors and worse outcomes after stroke in non-white patients compared to whites. Whether similar results still apply in the post mechanical thrombectomy era remains unknown.

Methods: The STAR registry combined the prospectively maintained databases of 11 thrombectomy-capable stroke centers in the US, Europe, and Asia. Consecutive patients who underwent MT were included in these analyses. Baseline features, risk factors, location of occlusion, time from symptom onset, tPA receipt, procedural complication rates, symptomatic hemorrhage, and long-term functional outcome were compared between white and non-white patients. Multivariate logistic regression analysis was performed to evaluate the impact of race on long-term outcome.

Results: Total of 2,284 patients were included in this analysis. Of those, 1,436 (62.9%) were white. Baseline features and outcomes are summarized in table 1. Non-white patients were older ( 71 Vs 66, p=<0.001), more likely to be female ( 53.1% Vs 48.5%, p=0.034), had lower NIHSS on admission ( 15 Vs 16, p=<0.001), higher prevalence of hypertension, hyperlipidemia, diabetes, lower incidence of atrial fibrillation, higher rate of tPA receipt, shorter onset to groin access times, and longer procedural times. White patients had higher rates of successful revascularization (77.4% Vs 72.3%, p=0.006) and longer hospital stay. On multivariate logistic regression analysis, white race was an independent predictor of good 90-day outcome (OR 1.35, 95% CI 1.03-1.76, P=0.031) after controlling for age, sex, location of occlusion, IV-tPA, ASPECT score, procedure duration and final TICI score.

Conclusion: In this study, white race was independent predictor of good 90-day outcome. This finding could be due to higher prevalence of vascular risk factors in non-white patients.

Abstract WP26: Use of Balloon-guide Catheter Bridges the Difference in Technical Outcomes Between Adapt and Stent Retriever Thrombectomy for Ischemic Stroke - Insights From STAR Collaboration

Introduction: Recently completed randomized controlled trials comparing aspiration thrombectomy (ADAPT) to stent retriever thrombectomy (SRT) demonstrated similar clinical outcomes, but faster thrombectomy procedure time in the ADAPT group. This study evaluates the difference in technical outcomes between ADAPT and SRT combined with balloon-guide catheters (BGC).

Methods: Patients undergoing thrombectomy for acute ischemic stroke at 12 comprehensive stroke centers in the US and Europe between 01/2013 and 12/2018 were reviewed. Data was collected retrospectively from patient charts, procedure notes, and patient follow-up in neurology clinics. Clinical endpoint was the modified Rankin score (mRS) at 90-days, and technical outcomes were procedure time, total attempts, and mTICI scores.

Results: The study included 2,016 patients (mean age 69±15) who underwent stroke thrombectomy using ADAPT (46%), SRT (46%), or SRT+BGC (8%). Similar baseline characteristics were observed between the three groups, and no significant difference in mRS scores at 90-days between the three groups in univariate and multivariate analyses. Thrombectomy performed using SRT+BGC required significantly shorter procedure time compared to SRT (35 vs 61 min, p<0.001) that was comparable to ADAPT (36 min, p>0.1). However, use of SRT+BGC required significantly lower number of aspiration attempts compared to ADAPT (median 1 vs. 2, p<0.05). On multivariate linear regression, use of SRT+BGC independent predicted a significant reduction in procedure time compared to SRT (coefficient=-30.6, p<0.001), and significantly lower number of attempts compared to ADAPT (coefficient=-0.4, p=0.01). SRT+BGC was an independent predictor of higher mortality compared to ADAPT (OR=2.4, p<0.01), despite comparable rates of favorable outcomes (mRS 0-2) between the two groups. Use of SRT+BGC was not an independent predictor of symptomatic hemorrhage or complications compared to SRT or ADAPT.

Conclusions: This study shows that although ADAPT allows for faster procedure time compared to SRT, the use of BGC in SRT allows for a comparable procedure time to ADAPT with similar overall rates of favorable outcome, complications and hemorrhage. Mortality was higher with the use of BGC compared to ADAPT.

Abstract TP15: A Multicenter Study Comparing Solumbra to Standard Aspiration and Stent Retriever Thrombectomy

Background: Standard mechanical thrombectomy (MT) techniques utilized include aspiration thrombectomy (ADAPT), stent retriever (SR), and a combination of both (Solumbra). Many studies compare outcomes between ADAPT and SR; however, there has yet to be a large multicenter investigation comparing ADAPT and SR to Solumbra.

Methods: All patients from the participating STAR collaboration who underwent MT from 2015-2019 were included. Patients were analyzed by first MT technique utilized (ADAPT, SR, or Solumbra). Univariable and multivariable linear regression was utilized to analyze the MT technique association to number of thrombectomy attempts and procedure time. Univariable and multivariable logistic regression was utilized to determine the association between MT technique and the following outcomes: recanalization, symptomatic hemorrhage, 90-day functional independence, or 90-day mortality. P value less than 0.5 was considered significant.

Results: A total of 2515 MT for stroke were identified: 1155 (46%) ADAPT, 735 (29%) SR, 625 (25%) Solumbra. Patients who received Solumbra MT were older (p<0.001), had higher IV-tPA administration rates (p<0.01), and lower onset-groin times (p<0.01). Separate multivariable linear regression analyses revealed that Solumbra technique had significantly high procedure times (OR 10.2, p<0.001) but less thrombectomy attempts (OR -0.8, p<0.001) compared to other MT techniques. There was no difference in recanalization success between techniques (ADAPT 85%, SR 84%, Solumbra 86%). Compared to Solumbra, ADAPT and SR thrombectomy had significantly lower incidence of symptomatic hemorrhage (ADAPT OR 0.32, p=0.009; SR OR 0.39, p=0.039) and ADAPT had a significantly lower likelihood of mortality (OR 0.50, p<0.001). There was no difference in 90-day functional independence (mRS≤2) rates between MT techniques.

Conclusion: Compared to standard ADAPT and SR thrombectomy, the Solumbra technique for MT is a longer procedure that results in an increased likelihood of hemorrhage and 90-day mortality.

Abstract TP24: Radiological and Symptomatic Hemorrhagic Transformation Post Endovascular Thrombectomy for Both Anterior and Posterior Large Vessel Occlusion Ischemic Stroke - Insights From STAR Collaboration

Introduction: Radiological hemorrhagic transformation (rHT) and symptomatic intracranial hemorrhage (sICH) remain a major complication of mechanical thrombectomy (MT) in acute stroke. Our aim is to identify independent predictors of rHT and sICH.

Methods: A retrospective multicenter international study across the US and Europe included 2499 patients, 18 years or older, who underwent EVT for acute stroke from 2015-2019. rHT is defined as any intracranial hemorrhage post MT and subgrouped per ECASS II as petechial (HI), parenchymal hematoma without (PH1) and with mass effect (PH2) and subarachnoid hemorrhage (SAH). sICH was defined as presence of PH2 or SAH. Functional outcomes were described using the 90-day modified Rankin score (mRS) as “good” 0-2 or “poor” 3-6. Multivariable logistic regression model was used to identify predictors of rHT and sICH.

Results: 600 (24%) had rHT and 145 (5.8%) had sICH. On multivariable regression model, independent predictors for both rHT and sICH were higher admission NIHSS (OR 1.03, p<.001 vs. OR 1.04, p<.001), lower ASPECTS (OR .82, p<.001 vs. OR .83, p<.001) and higher number of thrombectomy attempts (OR 1.08, p.013 vs. OR 1.08, p .014). Patients with hyperlipidemia (OR .77, p .03 vs. OR .75, p.02) or posterior circulation strokes (OR .59, p .013 vs. OR .58, p .01) had significantly lower rates of rHT and sICH. Both rHT and sICH are independently associated with poor functional outcomes (OR .5, p<.001; OR .29, p .006).

Conclusion: Compared to posterior circulation, anterior circulation strokes have higher rates of rHT and sICH. Baseline hyperlipidemia is protective for rHT or sICH post MT and this association needs further study. Clinical severity of stroke, poor ASPECTS on admission and higher thrombectomy attempts are associated with higher rates of rHT or sICH. Both rHT and sICH are independently associated with poor functional outcomes.

Abstract WP3: Predictors and Outcomes of Successful First Pass in Neurothrombectomy- Insights From the STAR Collaboration

Introduction: Shorter procedure time during neurothrombectomy is a strong predictor for good outcomes in stroke patients with large vessel occlusion. We sought to assess the predictors and outcomes of successful first pass (SFP) using multi-center investigator-initiated database.

Methods: Prospectively collected neurothrombectomy data from 11 thrombectomy-capable stroke centers was combined in the Stroke Thrombectomy and Aneurysm Registry (STAR). SFP was defined by achieving modified Thrombolysis in Cerebral Infarction (mTICI) score≥2b with a single thrombectomy device pass. We compared the baseline characteristics, procedural metrics, rate of symptomatic intracranial hemorrhage (sICH), and long-term functional outcomes between SFP and non-SFP patients. A multivariate logistic regression analysis was used to assess the predictors of SFP and evaluate whether SFP was an independent predictor for good long-term functional outcomes (90-day mRS≤2).

Results: A total of 733 SFP patients and 1134 non-SFP patients were included in this analysis. SFP patients were older (73 vs. 70, P=0.001), had higher Alberta Stroke Program Early CT (ASPECT) score on presentation (9 vs. 8, P=0.002). The use of Solumbra technique was an independent predictor of SFP (OR 1.2, 95% CI 1.1-1.4, P=0.004) after controlling for age, sex, location of occlusion, National Institute of Health stroke scale (NIHSS) on presentation, intravenous alteplase (IV-tPA), and onset to groin (OTG) time. SFP was an independent predictor for good long-term functional outcomes (OR1.6, 95% CI 1.1-2.3, P=0.008) after controlling for age, sex, location of occlusion, NIHSS on presentation, OTG time, IV-tPA, procedure technique, and procedure duration.

Conclusion: SFP lead to higher rates of functional independence in stroke patients with large vessel occlusion. These records reiterate the importance of SFP as a benchmark measure for stroke thrombectomy devices.

Abstract TP12: The Trend of Successful First Pass in M2 Segment Stroke Thrombectomy- Insights From the STAR Collaboration

Introduction: Stroke thrombectomy devices and the experience of neurointerventionists have improved significantly over the last few years making targeting distal occlusions such as of the M2 segment of the middle cerebral artery more feasible. We aimed to study the trend in the successful first pass (SFP) of M2 occlusions over time using the data from a contemporary multicenter registry.

Methods: We reviewed the data from the Stroke Thrombectomy and Aneurysm Registry (STAR), which included data from 11 thrombectomy-capable stroke centers to identify stroke patients who underwent mechanical thrombectomy of M2 segment occlusion. SFP was defined by achieving modified Thrombolysis in Cerebral Infarction (mTICI) score≥2b with a single thrombectomy device pass. We analyzed the linear trendline of the rate of SFP over time. Then, we used a logistic regression model to assess predictors of SFP of M2 segment occlusion.

Results: We included 401 patients who underwent stroke thrombectomy of M2 occlusion; median age was 71 (IQR 60-80), 212 (52.9%) were females, 174 (43.4%) were white, National Institute of Health stroke scale (NIHSS) was 14 (IQR 8-19), Alberta Stroke Program Early CT (ASPECT) score on presentation was 9 (IQR 7-10) and onset wot groin time was 287 (IQR 181-454). SFP was achieved in 118 (29.4%) patients (linear trendline over time is in Figure 1). Presenting after 2014 was an independent predictor of SFP (OR 1.9, 95% CI 1.1-3.2, P=0.019) after controlling for age, sex, NIHSS on presentation, intravenous alteplase (IV-tPA), and onset to groin time.

Conclusion: SFP rate of M2 segment occlusion has increased after 2014 likely secondary the improvement in stroke thrombectomy devices and neurointerventionists experience.

Abstract WMP4: Predictors of Functional Recovery After Thrombectomy in Posterior Circulation Stroke - Insights From the STAR Collaboration

Introduction: Endovascular thrombectomy (ET) for treating acute stroke in the real-world has expanded beyond the selection criteria used in major trials, and currently includes posterior circulation strokes. Posterior circulation stroke is believed to have worse outcomes than anterior circulation stroke, and its outcomes following ET are still being studied. We explored the major determinants of functional recovery after ET for posterior circulation stroke in a large cohort of patients from the Stroke Thrombectomy and Aneurysm Registry (STAR).

Methods: STAR includes patients undergoing ET for acute ischemic stroke at 12 comprehensive stroke centers in the US and globally. Data on patient demographics, technical and clinical outcomes was reviewed retrospectively from patient charts and procedure notes. Primary outcomes was the modified Ranking Score (mRS) at 90 days dichotomized into favorable (mRS 0-2) and poor outcome (mRS 3-6).

Results: A total of 3850 patients were reviewed, of which 345 patients (mean age 60±14) were treated for posterior circulation stroke with predominantly basilar artery occlusion (80%). Patients were treated using aspiration thrombectomy (ADAPT, 39%), stent retriever thrombectomy (31%), combined approach (19%) or intracranial stenting (7%). The overall rate of favorable outcome was 33%. Patients with diabetes, high NIHSS on admission, and proximal occlusions had significantly higher odds of poor functional outcomes on multivariate analysis (p<0.05). Compared to ADAPT thrombectomy, significantly higher odds for poor outcomes were observed with the use of stent retriever (aOR=0.84, p<0.01) or primary combined approach (aOR=2.85, p=0.05). The advantage of ADAPT on functional recovery compared to stent retrievers persisted when regression models were limited to patients with successful recanalization, or with basilar artery occlusions. No differences in complication and hemorrhage rates were observed.

Conclusions: Despite similar rates of functional recovery after ET for anterior circulation stroke between stent retriever and ADAPT, our analysis demonstrates that in posterior circulation stroke, ADAPT may lead to better functional outcomes compared to stent retriever without differences in safety profiles.

Abstract WMP11: Safety and Efficacy of Mechanical Thrombectomy in Patients With Minor Stroke Due to Large Vessel Occlusion- Insights From the STAR Registry

Introduction: Mechanical thrombectomy (MT) is the current standard of care treatment for patients presenting with severe symptoms due to large vessel occlusion (LVO); approximately 30% of patients with LVO however present with mild symptoms (NIHSS < 6). The safety and efficacy of MT in this group has not yet been established. The purpose of this study is to evaluate the safety of MT in patients presenting with mild symptoms due to LVO in a large multicenter registry.

Methods: STAR registry combined the prospectively maintained databases of 11 thrombectomy-capable stroke centers in the US, Europe and Asia. Patients who underwent MT were included in these analyses. Baseline features, risk factors, location of occlusion, time from symptom onset, tPA receipt, procedural complication rates, symptomatic hemorrhage, and long-term functional outcome were compared between patients with mild symptoms (NIHSS < 6) to those with severe symptoms (NIHSS ≥ 6).

Results: Total of 2,114 patients were included in this analysis. Of those, 162 patients presented with NIHSS ≥ 6. Baseline features and outcomes are summarized in table 1. There was no difference in age, or sex, tPA receipt, number of attempts, rate of successful revascularization, symptomatic hemorrhage, or length of hospital stay. Median ASPECTS score was 9 in the mild Vs 8 in the severe symptom group (p=< 0.001), there was a higher percentage of patients in the mild symptom group with hypertension, hyperlipidemia, and LVO in the posterior circulation. Conversely there were more patients with atrial fibrillation in the severe symptom group. Excellent outcome (mRS 0-2 at 90 days) was achieved in 69.8% patients in the mild group compared to 38.3% in the severe group, p=<0.001)

Conclusion: In patients with minor symptoms due to large vessel occlusion, mechanical thrombectomy appears to be safe with low complication rates. Approximately seventy percent of patients achieved excellent functional recovery.

Table 1:

Abstract TMP4: Impact of Bridging Therapy With Intravenous Thrombolysis Prior to Mechanical Thrombectomy in Patients With Large Vessel Occlusion- Insights From the STAR Registry

Introduction: Clinical trials have proven the safety and efficacy of mechanical thrombectomy (MT) with intravenous alteplase (tPA) compared to tPA alone in patients presenting with large vessel occlusion (LVO). The impact of tPA prior to MT on procedural metrics, successful revascularization, symptomatic hemorrhage and long-term functional outcome has not been established from large scale real-world studies. In this study we evaluate the impact of tPA prior to MT on procedural times, immediate and long-term outcomes.

Methods: The STAR registry combined prospectively maintained databases of 11 thrombectomy-capable stroke centers in the US, Europe and Asia. Patients who received mechanical thrombectomy with or without intravenous tPA prior to MT were included in these analyses. Baseline characteristics, procedural time, successful revascularization (TICI ≥ 2B), symptomatic intracranial hemorrhage (PH2), and long-term functional outcomes were compared between the two groups.

Results: Total of 1869 patients were included in this analysis. Of those, 907 received tPA prior to MT. Baseline features and outcomes are summarized in table 1. There were more white patients in the non-tPA group, and more patients in this group had atrial fibrillation and hyperlipidemia; otherwise there were no differences in baseline features between the two groups. Median NIHSS on admission was 16 in both groups, median ASPECTS was 9 in the tPA group versus 8 in the non-tPA group, p=0.208. Patients in the tPA group had higher rate of successful revascularization, lower number of revascularizations attempts and were more likely to achieve excellent long-term functional outcome. There was no difference in procedural time, rate of symptomatic hemorrhage or length of hospital stay.

Conclusion: Bridging therapy with intravenous tPA prior to mechanical thrombectomy may facilitate MT and yield to better long-term functional outcome.

Abstract 130: Outcomes of Rescue Endovascular Treatment of Acute Ischemic Stroke in Patients With Underlying Intracranial Atherosclerosis- Insights From the STAR Registry

Introduction: Mechanical Thrombectomy (MT) is currently the standard of care for patients presenting with emergent large vessel occlusion (ELVO) with salvageable tissue. A subgroup of patients with ELVO are found to have refractory occlusion due to underlying intracranial atherosclerosis (ICAS), often requiring angioplasty with or without stenting. Whether this treatment is safe or effective in this group of patients remains to be established. The purpose of this study is to investigate the safety, efficacy and long-term outcome of MT with rescue therapy in patients with ICAS.

Methods: STAR registry combined prospectively maintained databases of 11 thrombectomy-capable centers in the US, Europe and Asia. In this analysis, we included patients who underwent rescue balloon angioplasty and/or stenting in the setting of ELVO. A matched sample was produced by matching on the variables of age, admission NIHSS, and location of occlusion.

Results: Out of 2827 thrombectomy patients included in STAR registry, 190 patients received MT and required rescue angioplasty and/or stenting. Balloon angioplasty was performed on 116 patients, and 84 patients had intracranial stenting. Compared to the 161 ICAS patients matched to similar number of controls. There was no difference in age, race, sex, rate of IV tPA administration, ASPECTS score, or onset to groin time. Successful first attempt was higher in patients with embolic LVO (22 vs 52, p=0.001), procedural time was longer in patients with ICAS (47 min Vs 31 min, p=<0.001). There was no difference in symptomatic intracranial hemorrhage, or long term functional outcome.

Conclusion: In patients with ELVO with underlying ICAS requiring rescue angioplasty and/or stenting; despite longer procedural time and lower rate of first pass revascularization, rescue therapy appears to be safe with similar complication rates and long-term functional outcomes compared to patients with large vessel occlusion from embolic source.

Table 1:

Abstract WP17: Stent Retriever versus Aspiration Thrombectomy for Distal Occlusions in Acute Stroke - Insights From the STAR Collaboration

Introduction: Aspiration thrombectomy using the ADAPT technique has been shown to have similar efficacy to stent retriever thrombectomy (SRT) in randomized trials of proximal large vessel occlusions. In this work, we investigated the differences in technical and clinical outcomes between ADAPT and SRT for distal vessel occlusions from the Stroke Thrombectomy and Aneurysm Registry (STAR).

Methods: Patients undergoing thrombectomy for acute ischemic stroke at 12 comprehensive stroke centers in the US and Europe between 01/2013 and 12/2018 were reviewed. Data was collected retrospectively from patient charts, procedure notes, and patient follow-up in neurology clinics for patients with isolated distal artery occlusion including MCA2, MCA3/4, ACA1/2, and PCA2/3. Clinical endpoint was the modified Rankin score (mRS) at 90-days, and technical outcomes were procedure time, total attempts, and mTICI scores.

Results: A total of 464 patients (mean age 69±13.5 years) were treated with ADAPT (56%) or SRT (44%) for distal occlusions during the study period. Patients in the ADPAT group were mainly treated using 3MAX (36%), 4MAX (21%), ACE68/64 (20%), 5MAX/ACE (12%). SRT group included the use of Trevo (50%), Solitaire (44%), or both (5%). There were no significant differences in rates of good outcomes or successful recanalization between ADAPT and SRT groups on multivariate logistic regression analysis controlling for significant confounding variables (p>0.1). Use of SRT in distal occlusions was an independent predictor of longer procedure times compared to ADAPT on linear regression (coefficient=23, p<0.001), and there was a trend toward higher odds of symptomatic hemorrhage in the SRT group (OR=2.6, p=0.06) on multivariate analysis. There were no differences in mortality and complication rates between the two groups.

Conclusions: Both SRT and ADAPT thrombectomy lead to comparable rates of favorable outcome for distal vessel occlusion. SRT requires longer procedures and may be associated with higher rates of hemorrhage. Further randomized trials are needed to confirm whether either techniques may provide a better safety or efficacy profile in distal vessel occlusions.

Abstract 169: A Comprehensive Multicenter Evaluation of the Impact of Age on Stroke Thrombectomy Outcomes - Insights From the STAR Collaboration

Introduction: Elderly patients, octogenarians and nonagenarians, were excluded or under-represented in the majority of stroke endovascular thrombectomy (ET) trials. There is conflicting data on the outcomes of ET in the elderly. We evaluated age-dependent outcomes of ET for stroke in a large dataset from the Stroke Thrombectomy and Aneurysm Registry (STAR).

Methods: Patients undergoing ET for acute ischemic stroke at 12 comprehensive stroke centers in the US and Europe between 01/2013 and 12/2018 were reviewed. Data was collected retrospectively from patient charts, procedure notes, and patient follow-up in neurology clinics. The primary endpoint was the modified Rankin score (mRS) at 90-days which was dichotomized into good outcome (mRS 0-2) or poor outcome (mRS 3-6).

Results: Of 3,850 patients reviewed, 2,827 had 90-day follow-up (mean age 69±14), and were divided into 6 age groups: 20-49 (G1, 10%), 50-59 (G2, 10%), 60-69 (G3, 23%), 70-79 (G4, 27%), 80-89 (G5, 21%), 90 or more (G6, 4%). When adjusted for confounding variables, age was an independent predictor of poor outcome (OR=1.4, p<0.001) and mortality (OR=1.5, p<0.0001). When used as categorical variable, adjusted OR (aOR) for good outcomes were significantly lower in groups G2-G6 compared to G1 (p<0.01, figure), and OR for mortality were significantly higher in G2-G6 compared to G1 (p<0.01, figure). An age increment of 10 years was associated with 23% higher odds of symptomatic hemorrhage, and 50% higher odds of mRS 5-6. The impact of procedure time on good outcome (mRS 0-2) was also age-dependent with aOR=0.84 (p<0.05) in G1,2 compared to aOR=0.65 (p<0.05) in G5,6.

Conclusions: Age is a major predictor of functional recovery after ET, and this study demonstrates a clear age-dependent increase in rate of mortality and poor outcomes after ET with exponentially worse outcomes above 80 years of age. Complication rates were not age-dependent. Further studies are required to optimize patient selection for ET in the elderly.

Abstract 168: Outcomes of Intra-Arterial Tissue Plasminogen Activator Rescue Therapy During Stroke Thrombectomy-Insights From the STAR Collaboration

Introduction: Intra-arterial tissue plasminogen activator (IA-tPA) can be used as rescue therapy during mechanical thrombectomy for stroke patients, mostly in the setting of distal occlusion. The outcomes of IA-tPA has not been assessed in large-scale multi-center studies yet.

Methods: We used data from the Stroke Thrombectomy and Aneurysm Registry (STAR), which included prospectively maintained databases of 11 thrombectomy-capable stroke centers in the US, Europe, and Asia. We compared the baseline characteristics, procedural metrics, rate of symptomatic intracranial hemorrhage (sICH), and long-term functional outcomes between thrombectomy patients who received rescue IA-tPA and a control group of thrombectomy patients with matched age, National Institute of Health stroke scale (NIHSS) on presentation, location of occlusion and IV-tPA receipt.

Results: A total of 2827 thrombectomy patients were included in the STAR registry. Out of those, 205 patients received IA-tPA. We matched 191 patients from the IA-tPA group with a control group of 191 patients (table 1). No difference was seen in age, sex, race, vascular risk factors, or Alberta Stroke Program Early CT (ASPECT) score between both groups. In addition, procedural metrics, including onset to groin time, the procedure duration, and rate of successful recanalization (modified Thrombolysis in Cerebral Infarction score≥2b) were similar. Finally, similar outcomes were noted in both groups, including the rate of sICH and good 90-day functional outcome (modified Rankin scale≤2).

Conclusion: The use of IA-tPA as an adjunctive treatment to mechanical thrombectomy was safe but did not result in a higher rate of successful recanalization or good long-term functional outcomes.

Flow Diversion for Treatment of Intracranial Aneurysms in Pediatric Patients: Multicenter Case Series

BACKGROUND

Though the Pipeline Embolization Device (Medtronic) is approved for use in adults 22 yr and older, the high efficacy and long-term durability of the device is attractive for treatment of intracranial aneurysms in younger patients who often have aneurysms less amenable to traditional endovascular treatments.

OBJECTIVE

To report technical, angiographic, and clinical outcomes in patients aged 21 or below undergoing flow-diversion treatment for intracranial aneurysms.

METHODS

Retrospective review across 16 institutions identified 39 patients aged 21 or below undergoing 46 treatment sessions with Pipeline Embolization Device placement between 2012 and 2018. A total of 50 intracranial aneurysms were treated. Details regarding patient demographics, aneurysm characteristics, treatment considerations, clinical outcomes, and aneurysm occlusion were obtained and analyzed in a multicenter database.

RESULTS

A total of 70% of patients were male. Nonsaccular morphology was seen in half of identified aneurysms. Six aneurysms were giant, and five patients were treated acutely after ruptured presentation. Eight patients were younger than 10 yr of age. Complete aneurysm occlusion was seen in 74% of treated aneurysms. Three aneurysms (6%) were retreated. A total of 83% of patients had a modified Rankin Scale scores of ≤2 at last clinical follow-up. There were 2 early mortalities (4.3%) in the immediate postprocedure period because of rerupture of a treated ruptured aneurysm. No recanalization of a previously occluded aneurysm was observed.

CONCLUSION

Flow-diversion treatment is a safe and effective treatment for intracranial aneurysms in patients younger than 22 yr. Rates of complete aneurysm occlusion and adverse events are comparable for rates seen in older patients.

Abstract TMP7: Endovascular Recanalization of Intracranial Arterial Stenosis in Patients With Recurrent or Progressive Symptoms Despite Medical Management

Background and Objective: The optimal management of intracranial arterial stenosis is unclear, particularly in patients who have failed medical management. We report a multicenter real-world experience of endovascular recanalization of intracranial atherosclerotic stenosis refractory to aggressive medical therapy.

Methods: Retrospective multicenter case series of consecutive endovascularly treated patients presenting with symptomatic (TIA or stroke) who had failed medical therapy were identified. All of the patients were considered to be at high risk with unstable symptomatic intracranial stenosis and progression or recurrence of symptoms despite the best medical management and underwent endovascular intervention either with stenting and/or balloon angioplasty.

Results: 98 patients presented with recurrent TIAs (n= 40) or recurrent or progressive strokes (n= 58) and were treated in 8 stroke centers from 2009 to 2017. All patients were treated either with dual antiplatelet therapy (84%) or anticoagulation and all had statin therapy prior to recurrence or progression of their symptoms. There was one periprocedural perforation resulting in patient death. There were 3 patients who had periprocedural strokes and 2 patients had symptomatic intraparenchymal hemorrhage with a total of four (4%) periprocedural mortality. The all-cause mortality rate at discharge was 6%. At 90-day follow-up, 7 (10%) patients had TIAs and 2 (3%) patients had ipsilateral strokes, and 78% of patients had mRS of 2 or less.

Conclusion: Endovascular recanalization of unstable intracranial atherosclerotic stenosis who have failed medical therapy is feasible and safe.

A multicenter study evaluating the frequency and time requirement of mechanical thrombectomy

Introduction

There are few published data evaluating the incidence of mechanical thrombectomy among stroke centers or the times at which they occur.

Methods

A multicenter retrospective study was performed to identify all patients undergoing emergent thrombectomy for acute ischemic stroke during a 3-month period (June through August 2016). Consultations that did not undergo thrombectomy were not included.

Results

Ten institutions participated in the study. During the 92-day study period, a total of 189 patients underwent mechanical thrombectomy. The average number of procedures per hospital over the study period was 18.9 (average of 0.2 cases per day per or 75.6 cases per year). This ranged from 0.09 cases per day at the lowest volume center to 0.49 cases per day at the highest volume center. Procedures were more common on weekdays (p<0.001) and during non-work hours (p<0.001). The most common period for thrombectomy procedures was between 20:00 and 21:00 hours. The median time from notification to groin puncture was 84 min (IQR 56–145 min) and from puncture to closure was 57 min (IQR 33–80 min). The median time from imaging completion to procedural start was 52 min longer for non-work hours than during work hours (p<0.001). There were no differences in procedural length based on day of the week or time of day.

Conclusions

These findings indicate that the majority of mechanical thrombectomy cases occur during non-work hours, with associated off-hours delays, which has important operational implications for hospitals implementing stroke call coverage.

Effective Surgical Management of Competitive Venous Outflow Restriction After Radiosurgery for Cerebral AVMs: Report of 2 Cases

BACKGROUND

Intracranial arteriovenous malformations (AVMs) are complex pathologies. For patients who do not present with hemorrhage, treatment strategies are often predicated on reducing the risk of hemorrhage and minimizing morbidity. Outcomes vary according to the efficacy of treatment selected. Radiosurgical treatment of certain AVMs can result in incomplete obliteration and may also have only a minimal effect on the presenting nonhemorrhagic symptoms.

CASE DESCRIPTIONS

We present 2 cases of patients with AVMs who were initially treated with radiosurgery. Both patients' primary clinical symptoms were headaches, which persisted after radiosurgical treatment but abated after subsequent microsurgical resection with or without endovascular embolization.

CONCLUSION

Venous outflow obstruction is likely a sizable contributive factor in occipital AVMs among patients who present with headaches and symptoms of intracranial hypertension. Because these high-flow lesions may be suboptimally responsive to stereotactic radiosurgery, microsurgical resection, with or without adjunctive endovascular embolization, should be considered as an initial and definitive treatment strategy. Optimal outcomes may be achieved in patients with a visual deficit that is anatomically correlated to their AVMs.

Abstract 117: A Six Minute MRI Protocol for Evaluation of Acute Ischemic Stroke: Pushing the Boundaries

Purpose: Multimodal cerebrovascular CT and MR can now provide information about tissue viability, site of occlusion, and collateral status in patients with acute ischemic stroke (AIS). If MRI is to compete with CT for evaluation of AIS, there is need for further improvements in acquisition speed. The purpose of this study was to establish the feasibility of a fast MR protocol with a 6 minute acquisition time for evaluation of AIS.

Methods: Patients with suspicion of AIS and absence of MRI contraindications were prospectively enrolled. A combination of echo-planar imaging (EPI) and parallel acquisition technique were used on a 3T MR scanner to accelerate the acquisition time. The imaging protocol included: DWI (1 min), EPI-FLAIR (52 sec), EPI-GRE (50 sec), contrast-enhanced MR angiography (CE-MRA) of the entire supra-aortic arteries (20 sec), and DSC perfusion (2 min). Using a modified 2-phase contrast injection scheme, high spatial resolution CE-MRA of the supra-aortic arteries was performed just before DSC perfusion without the need for additional contrast. Image analysis was performed independently by two neuroradiologists and interobserver agreement was calculated using Kappa test.

Results: A total of 50 patients were included. Diagnostic image quality was achieved in 100% of DWI, 96% EPI-FLAIR, 98% EPI-GRE, 90% neck MRA, 96% of brain MRA, and 94% of DSC perfusion scans. Thirty eight patients (76%) had acute infarction. Using Tmax perfusion maps and applying DEFUSE criteria, 42% of patients had perfusion-diffusion mismatch with interobserver agreement of k=0.90. The mean of the signal-intensity-ratio values of the infarction on EPI-FLAIR was 1.08 for patients presenting < 4.5 hours (n=16) and 1.35 for patients presenting > 4.5 hours (n=22) from the time of imaging. Three patients had evidence of intracranial hemorrhage detected on EPI-GRE and confirmed by non-contrast CT. CE-MRA showed 27 segmental stenoses of the extra-cranial arteries and 24 segmental stenoses of the intracranial arteries with interobserver agreement of k= 0.82 and 0.74 respectively.

Conclusion: Described multimodal MR protocol is feasible for evaluation of patients with AIS and can result in significant reduction in scan time rivaling that of the multimodal CT protocol.

Tubo-ovarian abscess in virginal adolescent females: a case report and review of the literature

BACKGROUND

A tubo-ovarian abscess (TOA) is a serious complication of pelvic inflammatory disease (PID), predominantly polymicrobial and present in sexually active women. TOA in virginal adolescent females are extremely rare but have serious and lifelong consequences.

CASE

A 13 y.o. virginal female presented to the Emergency Room of a tertiary care pediatric hospital with abdominal pain and vomiting. Imaging suggested bowel compromise with potential perforation. An exploratory laparotomy revealed TOA which grew Escherichia Coli. This is the first reported case of Escherichia Coli TOA due to suspected bowel translocation.

CONCLUSION

Review of the literature identified 8 cases of TOA in virginal adolescents. Given the severity of outcomes following TOA, this pathology should be considered in the differential diagnosis of virginal adolescents who present with fever and abdominal pain. If suspected, a prompt gynecology consult should be initiated, followed by a first line antibiotic therapy and when indicated, surgical drainage.

Non-hodgkin B-cell lymphoma of the ovary in a child with Ataxia-telangiectasia

BACKGROUND

Ataxia-telangiectasia is a multisystem, life-limiting, recessively inherited genetic disorder caused by mutations in the Ataxia-telangiectasia mutated gene. It is characterized by the onset of changes in neurological and immunological development, organ maturation in childhood, as well as a high incidence of malignancies.

CASE

We describe a case of an 11-year-old girl with a history of progressive ataxia and new finding of bilateral pelvic masses. Given an elevated alpha-fetoprotein, the pre-operative working diagnosis was a malignant germ cell tumor. Final ovarian pathology revealed a non-Hodgkin B-cell lymphoma with Burkitt-like morphology.

SUMMARY

We present the first case of a primary ovarian non-Hodgkin B-cell lymphoma in a child with Ataxia-telangiectasia.