Large Vessel Occlusion Acute Ischemic Stroke Research Articles

Sex Differences in Outcomes after Endovascular Thrombectomy for Patients with Acute Ischemic Stroke.

Endovascular thrombectomy (EVT) is the standard of care for patients with large-vessel occlusion acute ischemic stroke (AIS). There may be differing recanalization effectiveness based on patients' sex, and understanding such variations can improve patient outcomes by adjusting for differences. We aimed to assess the sex differences in outcome after EVT for patients with AIS. We retrospectively analyzed 250 consecutive AIS patients who underwent EVT from July 2019 to February 2022 across two large comprehensive tertiary care stroke centers in China. Outcomes of male patients were compared to females, where poor outcome was defined as a modified Rankin score (mRS) of 3-6 at 90 days. Male patients had higher rates of symptomatic intracranial hemorrhage (sICH) (12.50% vs 4.05%, p = 0.042) and higher hospitalization costs (114541.08 vs. 105790.27 RMB, p = 0.024). Male patients also had a longer median onset-to-needle time (ONT) (146.00 (104.00, 202.00) vs. 120.00 (99.25, 144.75), p = 0.026). However, there were no differences in hospitalization length (p = 0.251), 90-day favorable outcome (p = 0.952), and 90-day mortality (p = 0.931) between the sexes. Female patients had lower hospitalization costs and sICH rates than males after EVT for AIS. Identifying such differences and implementing measures, including adaptations to workflow optimization, would help to reduce the ONT and last known normal-to-puncture-time seen in males to improve patient outcomes. Despite such variations, favorable outcomes and mortality are similar in female and male AIS patients.

The volume of steal phenomenon is associated with neurological deterioration in patients with large-vessel occlusion minor stroke not eligible for thrombectomy.

A significant number of patients who present with mild symptoms following large-vessel occlusion acute ischemic stroke (LVO-AIS) are currently considered ineligible for EVT. However, they frequently experience neurological deterioration during hospitalization. This study aimed to investigate the association between neurological deterioration and hemodynamic impairment by assessing steal phenomenon derived from blood oxygenation-level dependent cerebrovascular reactivity (BOLD-CVR) in this specific patient cohort. From the database of our single-center BOLD-CVR observational cohort study (June 2015-October 2023) we retrospectively identified acute ischemic stroke patients with admission NIHSS < 6, a newly detected large vessel occlusion of the anterior circulation and ineligible for EVT. Neurological deterioration during hospitalization as well as outcome at hospital discharge were rated with NIHSS score. We analyzed the association between these two outcomes and BOLD-CVR-derived steal phenomenon volume through regression analysis. Additionally, we investigated the discriminatory accuracy of steal phenomenon volume for predicting neurological deterioration. Forty patients were included in the final analysis. Neurological deterioration occurred in 35% of patients. In the regression analysis, a strong association between steal phenomenon volume and neurological deterioration (OR 4.80, 95% CI 1.32-31.04, p = 0.04) as well as poorer NIHSS score at hospital discharge (OR 3.73, 95% CI 1.52-10.78, p = 0.007) was found. The discriminatory accuracy of steal phenomenon for neurological deterioration prediction had an AUC of 0.791 (95% CI 0.653-0.930). Based on our results we may distinguish two groups of patients with minor stroke currently ineligible for EVT, however, showing hemodynamic impairment and exhibiting neurological deterioration during hospitalization: (1) patients exhibiting steal phenomenon on BOLD-CVR imaging as well as hemodynamic impairment on resting perfusion imaging; (2) patients exhibiting steal phenomenon on BOLD-CVR imaging, however, no relevant hemodynamic impairment on resting perfusion imaging. The presence of BOLD-CVR derived steal phenomenon may aid to further study hemodynamic impairment in patients with minor LVO-AIS not eligible for EVT.

Contrast Staining in Noninfarcted Tissue after Endovascular Treatment of Acute Ischemic Stroke.

Contrast staining is a common finding after endovascular treatment of acute ischemic stroke. It typically occurs in infarcted tissue and is considered an indicator of irreversible brain damage. Contrast staining in noninfarcted tissue has not been systematically investigated. We sought to assess the incidence, risk factors, and clinical significance of contrast staining in noninfarcted tissue after endovascular treatment. We conducted a retrospective review of consecutive patients who underwent endovascular treatment for anterior circulation large-vessel occlusion acute ischemic stroke. Contrast staining, defined as new hyperdensity on CT after endovascular treatment, was categorized as either contrast staining in infarcted tissue if the stained region demonstrated restricted diffusion on follow-up MR imaging or contrast staining in noninfarcted tissue if the stained region demonstrated no restricted diffusion. Baseline differences between patients with and without contrast staining in noninfarcted tissue were compared. Logistic regression was used to identify independent associations for contrast staining in noninfarcted tissue after endovascular treatment. Among 194 patients who underwent endovascular treatment for large-vessel occlusion acute ischemic stroke and met the inclusion criteria, contrast staining in infarcted tissue was noted in 52/194 (26.8%) patients; contrast staining in noninfarcted tissue, in 26 (13.4%) patients. Both contrast staining in infarcted tissue and contrast staining in noninfarcted tissue were noted in 5.6% (11/194). Patients with contrast staining in noninfarcted tissue were found to have a higher likelihood of having an ASPECTS of 8-10, to be associated with contrast staining in infarcted tissue, and to achieve successful reperfusion compared with those without contrast staining in noninfarcted tissue. In contrast staining in noninfarcted tissue regions, the average attenuation was 40 HU, significantly lower than the contrast staining in infarcted tissue regions (53 HU). None of the patients with contrast staining in noninfarcted tissue had clinical worsening during their hospital stay. The median discharge mRS was significantly lower in patients with contrast staining in noninfarcted tissue than in those without (3 versus 4; P = .018). No independent predictors of contrast staining in noninfarcted tissue were found. Contrast staining can be seen outside the infarcted tissue after endovascular treatment of acute ischemic stroke, likely attributable to the reversible disruption of the BBB in ischemic but not infarcted tissue. While generally benign, understanding its characteristics is important because it may mimic pathologic conditions such as infarcted tissue and cerebral edema.

Machine Learning–Enabled Automated Large Vessel Occlusion Detection Improves Transfer Times at Primary Stroke Centers

Background Accelerating door‐in‐door‐out (DIDO) times at primary stroke centers (PSCs) for patients with large vessel occlusion (LVO) acute ischemic stroke transferred for possible endovascular stroke therapy (EVT) is important to optimize outcomes. Here, we assess whether automated LVO detection coupled with secure communication at non‐EVT performing PSCs improves DIDO time and increases the proportion of patients receiving EVT after transfer. Methods From our prospectively collected multicenter registry, we identified patients with LVO acute ischemic stroke that presented to one of 7 PSCs in the Greater Houston area from January 1, 2021, to February 27, 2022. Noncontrast computed tomography and computed tomographic angiography were performed in all patients at the time of presentation, per standard of care. A machine learning (artificial intelligence [AI]) algorithm trained to detect LVO (Viz.AI) from computed tomographic angiography was implemented at all 7 hospitals. The primary outcome of the study was DIDO at the PSCs and was determined using multivariable linear regression adjusted for sex and on/off hours. Secondary outcomes included likelihood of receiving EVT post‐transfer. Results Among 115 patients who met inclusion criteria, 80 were evaluated pre‐AI and 35 post‐AI. The most common occlusion locations were middle cerebral artery (51.3%) and internal carotid artery (25.2%). There were no substantial differences in demographics or presentation characteristics between the 2 groups. Median time from onset to PSC arrival was 117 minutes (interquartile range, 54–521 minutes). In univariable analysis, patients evaluated at the PSCs after AI implementation had a shorter DIDO time (median difference, 77 minutes; P &lt;0.001). In multivariable linear regression, patients evaluated with automated LVO detection AI software were associated with a 106‐minute (95% CI, −165 to −48 minutes) reduction in DIDO time but no difference in likelihood of EVT post‐transfer (odd ratio, 2.13 [95% CI, 0.88–5.13). Conclusion Implementation of a machine learning method for automated LVO detection coupled with secure communication resulted in a substantial decrease in DIDO time at non‐EVT performing PSCs.

Abstract TP82: Effect of Stroke Etiology and Treatment Intervention for Young Adults With Large Vessel Occlusion- Acute Ischemic Stroke: Results From the Cleveland Clinic Young Adult Retrospective Cohort Study

Introduction: The incidence of Large Vessel Occlusion-Acute Ischemic Stroke (LVO-AIS) continues to increase in young adults. Although young adults who undergo mechanical thrombectomy have favorable outcomes, it is unclear if stroke etiology affects rehabilitation outcomes &amp; discharge destination for these patients. Hypothesis: Large artery atherosclerosis (LAA) results in worse outcomes as compared to other etiologies in terms of discharge destination. Methods: This retrospective study cohort comprised of patients 18-50 years of age, presenting to the Cleveland Clinic Stroke Enterprise, with LVO-AIS from January 2017 to December 2021. Patients with LVO on CTA or MRA at presentation were included. We then assessed patients with LAA and compared their discharge destination to patients with other etiologies. Results: Out of 1210 patients with AIS, 172 with LVO were included. 31 patients (18%) had stroke etiology as Large Artery Atherosclerosis (per TOAST criteria). Among patients with LAA, the median initial NIHSS was 6 and median discharge NIHSS 4. 16.2% of these patients received IV thrombolysis and 32.4% underwent mechanical thrombectomy (MT). 48.4% patients were discharged to acute rehabilitation, 32.3% went home, 12.9% SNF, and 6.5% deceased. In contrast, patients for whom TOAST criteria was not “Large Artery Atherosclerosis”, had a median initial NIHSS 9 and median discharge NIHSS 2. 31.2% received IV thrombolysis and 43.9% underwent MT. Their discharge destination was home for 56%, acute rehabilitation for 27.7%, LTAC for 5%, 2.8% SNF, and 8.5% deceased. Both these groups had similar initial mRS. Conclusions: Young adults with LVO-AIS had good outcomes irrespective of stroke etiology, however LAA patients were less likely to be discharged home compared to other etiologies, likely owing to less functional recovery as compared to other etiologies. Further studies are needed to determine why young adults with LVO with LAA have worse outcomes.

Abstract TMP57: User Engagement is Associated With Clinical Impacts of Automated LVO Detection Software

Introduction: Machine learning (ML)-based acute ischemic stroke (AIS) large vessel occlusion (LVO) detection algorithms can reduce door to groin time (DTG). Here, we examine whether the dependency of these benefits on end user engagement and interaction. Methods: This analysis was conducted as a pre-planned post hoc analysis of our multicenter, prospective randomized clinical trial (NCT05838456). ML-based LVO detection software was implemented at 4 comprehensive stroke centers in the greater Houston area in a stepped fashion between Jan 2021 and March 2022. Patients were included in this analysis if they underwent EVT for LVO AIS. Exclusion criteria included inter-hospital transfers or inpatient stroke alerts. ML-software utilization was quantified as the number of software interactions including imaging viewing and/or HIPAA-compliant text messaging and was trichotomized at the hospital level into low/medium/high. Primary outcome was the reduction in DTG relation to pre-ML implementation by hospital utilization level. Secondary outcomes included CT to groin puncture time, and sensitivity analyses in subsets of patients who did and did not have an LVO alert sent. Results: Among 243 patients that met inclusion criteria, median age was 70 (IQR 58-79), 50% were female and median NIHSS was 17 (IQR 11-22). There were 2 high-utilization centers interacting with the ML software mean 160 times, one medium center that interacted 64 times and one low center interacting 42 times during the study period. We observed a reduction on DTG of 11 minutes in the high-interaction center (p&lt;0.01) but no significant reduction in DTG in the medium or low-interaction centers. Similarly, time from CT scan initiation to groin puncture fell in the high-utilization centers by 32 minutes (p&lt;0.05) but no significant change in others. Without adjusting for hospital-level software utilization, there was no statistically significant reduction in DTG for patients analyzed by the ML software versus those that were not (p=0.35). Conclusion: The benefit of ML-enhanced LVO AIS workflows are dependent on user engagement.

Abstract 153: First Pass Effect in Mechanical Thrombectomy for Anterior Circulation Acute Ischemic Stroke is Modified by Procedure Time: Proposal of a New Measure for Thrombectomy Procedures

Objective: To determine whether first pass effect (FPE) after mechanical thrombectomy (MT) for anterior circulation large vessel occlusion acute ischemic stroke (LVO-AIS) is modified by procedural time (PT). Methods: The Stroke Thrombectomy and Aneurysm Registry (STAR), a multi-center international dataset, was retrospectively analyzed for anterior circulation LVO-AIS treated by MT who achieved excellent reperfusion (TICI 2c/3). The primary outcome was good functional outcome as defined by a 90-day modified Rankin Scale (mRS) 0-2. The primary study exposure was first pass success (FPS, 1 pass vs ≥2 passes) and the secondary exposure was PT. Logistic regression models were fit-adjusted and marginal effects used to assess the interaction of PT (≤30 vs &gt;30 minutes) and FPS, adjusting for potential confounders including time from last known well to start of MT. Results: A total of 1,310 patients had excellent reperfusion. These patients were divided into two cohorts based on PT: ≤30 minutes (777 patients, 59.3%) and &gt; 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=0.018). 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=0.001). However, there was no significant difference in the adjusted predicted probability of good outcome based on FPS in individuals with PT &gt;30 minutes (p=0.763). This relationship appeared identical in models with PT treated as a continuous variable. Conclusion: In a large, real-world, multi-national dataset, we find that FPE is importantly modified by PT. The added clinical benefit of FPE is lost in longer procedures (&gt;30 minutes). These data argue for a new metric for MT procedures, namely, FPE 30 , that better represents the ideal of fast, complete reperfusion with a single pass of a thrombectomy device.

Women With Large Vessel Occlusion Acute Ischemic Stroke Are Less Likely to Be Routed to Comprehensive Stroke Centers.

Background Prehospital routing of patients with large vessel occlusion (LVO) acute ischemic stroke (AIS) to centers capable of performing endovascular therapy may improve clinical outcomes. Here, we explore whether distance to comprehensive stroke centers (CSCs), stroke severity, and sex are associated with direct-to-CSC prehospital routing in patients with LVO AIS. Methods and Results In this cross-sectional study, we identified consecutive patients with LVO AIS from a prospectively collected multihospital registry throughout the greater Houston area from January 2019 to June 2020. Primary outcome was prehospital routing to CSC and was compared between men and women using modified Poisson regression including age, sex, race or ethnicity, first in-hospital National Institutes of Health Stroke Scale score, travel time, and distances to the closest primary stroke center and CSC. Among 503 patients with LVO AIS, 413 (82%) were routed to CSCs, and women comprised 46% of the study participants. Women with LVO AIS compared with men were older (73 versus 65, P<0.01) and presented with greater National Institutes of Health Stroke Scale score (14 versus 12, P=0.01). In modified Poisson regression, women were 9% less likely to be routed to CSCscompared with men (adjusted relative risk [aRR], 0.91 [0.84-0.99], P=0.024) and distance to nearest CSC ≤10 miles was associated with 38% increased chance of routing to CSC (aRR, 1.38 [1.26-1.52], P<0.001). Conclusions Despite presenting with more significant stroke syndromes and living within comparable distance to CSCs, women with LVO AIS were less likely to be routed to CSCs compared with men. Further study of the mechanisms behind this disparity is needed.

Effect of Stroke Etiology on Mechanical Thrombectomy Outcomes in Young Adults: A Retrospective Data Analysis (P8-5.021)

<h3>Objective:</h3> We sought to study mechanical thrombectomy (MT) outcomes in racially diverse young adult patients with large vessel occlusion-acute ischemic stroke (LVO-AIS) presenting to the Cleveland Clinic Stroke Enterprise, and assess if stroke etiology affected MT outcome. <h3>Background:</h3> LVO-AIS is considerably uncommon in young adults. They also have distinctively different stroke mechanisms. The data on whether varying etiologies in this age-group influence MT outcomes is unclear. <h3>Design/Methods:</h3> This retrospective study cohort comprised of patients 18–50 years of age, presenting with AIS from January 2017 to December 2021. Patients with LVO on CTA or MRA at presentation were included. We assessed demographics, stroke etiology (TOAST and ASCOD classifications), intervention received (IV-thrombolysis+/−MT) and MT outcomes. <h3>Results:</h3> Out of 1210 patients with AIS, 210 with LVO were included. 88 (41.9%) underwent MT (44.3% received IV-thrombolysis+ MT). 21 (10%) patients received only IV-thrombolysis; 101 (48.1%) received neither intervention. Among patients who underwent MT, median (IQR 25,75) age was 42 (36,46) years, 46.6% were females, 70.5% identified as “white”. Median iNIHSS was 12 (7.75,18.25); 78.3% had initial mRS 0. Median last known well to groin puncture time was 6.75 hours. 92% patients had favorable outcome (TICI 2b/2c/3). Median discharge NIHSS was 1.5 (0,7.5). Discharge mRS: 1 for 33% with large-artery atherosclerosis (LAA), 1 for 31.6% with cardio-embolism, 0 for 71.4% with stroke of other etiology, 0/1 for 45% of undetermined etiology. Our cohort’s stroke etiology- Per TOAST: 13.6% LAA, 0% small vessel disease (SVD), 29.5% cardio-embolism, 25% stroke of other etiology, 33% undetermined etiology. Per ASCOD: 31.8% LAA, 4.4% SVD, 45.4% cardiac, 13.6% other causes, 11.4% vessel dissection. <h3>Conclusions:</h3> In our cohort, a high proportion of patients were functionally independent after MT, with good outcome independent of stroke etiology. A large proportion of patients received no acute intervention. Further studies are needed to identify barriers to this in young adults. <b>Disclosure:</b> Dr. Bhayana has nothing to disclose. Dr. Handshoe has nothing to disclose. Dr. Chandra has nothing to disclose. Dr. Martucci has nothing to disclose. Mr. Reid has nothing to disclose. Miss Kharal has nothing to disclose. Miss A Saleem has nothing to disclose. Mr. Saleem has nothing to disclose. Andrew Schuster has nothing to disclose. Dr. Hussain has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Cerenovus. Dr. Hussain has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Tiger Medical. Dr. Toth has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Dynamed. Dr. Toth has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Microvention. Dr. Toth has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Medtronic. Dr. Kharal has nothing to disclose.

Outcomes After Endovascular Therapy With Procedural Sedation vs General Anesthesia in Patients With Acute Ischemic Stroke

General anesthesia and procedural sedation are common practice for mechanical thrombectomy in acute ischemic stroke. However, risks and benefits of each strategy are unclear. To determine whether general anesthesia or procedural sedation for anterior circulation large-vessel occlusion acute ischemic stroke thrombectomy are associated with a difference in periprocedural complications and 3-month functional outcome. This open-label, blinded end point randomized clinical trial was conducted between August 2017 and February 2020, with final follow-up in May 2020, at 10 centers in France. Adults with occlusion of the intracranial internal carotid artery and/or the proximal middle cerebral artery treated with thrombectomy were enrolled. Patients were assigned to receive general anesthesia with tracheal intubation (n = 135) or procedural sedation (n = 138). The prespecified primary composite outcome was functional independence (a score of 0 to 2 on the modified Rankin Scale, which ranges from 0 [no neurologic disability] to 6 [death]) at 90 days and absence of major periprocedural complications (procedure-related serious adverse events, pneumonia, myocardial infarction, cardiogenic acute pulmonary edema, or malignant stroke) at 7 days. Among 273 patients evaluable for the primary outcome in the modified intention-to-treat population, 142 (52.0%) were women, and the mean (SD) age was 71.6 (13.8) years. The primary outcome occurred in 38 of 135 patients (28.2%) assigned to general anesthesia and in 50 of 138 patients (36.2%) assigned to procedural sedation (absolute difference, 8.1 percentage points; 95% CI, -2.3 to 19.1; P = .15). At 90 days, the rate of patients achieving functional independence was 33.3% (45 of 135) with general anesthesia and 39.1% (54 of 138) with procedural sedation (relative risk, 1.18; 95% CI, 0.86-1.61; P = .32). The rate of patients without major periprocedural complications at 7 days was 65.9% (89 of 135) with general anesthesia and 67.4% (93 of 138) with procedural sedation (relative risk, 1.02; 95% CI, 0.86-1.21; P = .80). In patients treated with mechanical thrombectomy for anterior circulation acute ischemic stroke, general anesthesia and procedural sedation were associated with similar rates of functional independence and major periprocedural complications. ClinicalTrials.gov Identifier: NCT03229148.

Endovascular Stroke Therapy for Posterior Circulation Acute Ischemic Stroke Has Diminishing Benefit with Additional Passes

Background The relationship between pass number during endovascular stroke therapy (EST) and outcomes in anterior circulation large vessel occlusion (LVO) acute ischemic stroke (AIS) has been well studied. However, the association between EST attempts and outcomes for patients with posterior circulation LVO remains unclear. Methods From our prospectively maintained multicenter registry, we identified consecutive patients with LVO AIS who underwent EST. The number of thrombectomy passes and per‐pass reperfusion grades (thrombolysis in cerebral infarction) were recorded prospectively at the time of procedure. The primary outcome was the association of number of EST passes and functional independence (modified Rankin scale 0–2) at 90 days. Secondary outcomes included likelihood of attaining substantial reperfusion (thrombolysis in cerebral infarction 2b‐3). Results Among 894 patients with LVO AIS who underwent EST, median age was 68 [interquartile range 58–78], 49% were female, and median National Institutes of Health Stroke Scale was 16 [interquartile range 11–21]. Of this cohort, 86 (9.6%) had posterior circulation LVO, including 65 (7%) with basilar artery occlusion and 9 (1%) with vertebral artery occlusion. The diminishing benefit on successful reperfusion of additional passes was similar for anterior and posterior circulation AIS. Among patients with posterior circulation stroke, successful reperfusion with fewer passes was associated with greater likelihood of good functional outcome at 90 days (40.0% versus 4.8% modified Rankin scale 0–2 with 1–2 versus 3+ passes; P = 0.003). The likelihood of good outcome in patients with posterior circulation LVO treated with EST and successful reperfusion in 1–2 passes was comparable to patients with anterior circulation LVO (40.0% versus 40.2%, posterior versus anterior; P = 0.553). Conclusions The number of EST passes has a significant association with functional independence at 90 days for patients with posterior circulation LVO AIS. After 2 passes, there is significantly reduced benefit conferred by additional passes. Overall clinical outcomes in patients with successful reperfusion with 1–2 passes were similar in patients with posterior circulation compared with anterior circulation LVO.

Abstract WP9: Number Needed To Treat With Intravenous Tenecteplase To Reduce The Need For Mechanical Thrombectomy In Large Vessel Occlusion Acute Ischemic Stroke Patients: Real-world Experience Data.

Objective: We sought to describe short term outcomes in patients with large vessel occlusion acute ischemic stroke (LVOAIS) who were treated with intravenous tenecteplase (TNK) as compared to alteplase, focusing on reduction in the need for mechanical thrombectomy (MT). Background: In LVOAIS, TNK has shown improved reperfusion and outcomes with a similar safety profile to alteplase. Ultra-early reperfusion has been described with TNK which would prevent the need for MT. We analyze the magnitude of this effect in a “real-world” setting. Design/Methods: In this retrospective study, demographic, clinical, and imaging information from patients with LVOAIS treated with intravenous thrombolysis was collected. Data was compared between the group treated with TNK and alteplase. Results: One hundred eighty-six patients met the criteria for the study (LVOAIS and candidates for IV thrombolysis and MT). Of these, 144 patients received tPA and 42 received TNK. Nine had clinical improvement prior to groin puncture and did not require angiography. This phenomenon occurred in 2.1% who received IV tPA and 14.3% who received TNK (p=0.005). For 8.2 patients treated with TNK rather than tPA, one catheter angiography would be prevented. When combining the number of patients who had recanalization on angiography before MT, and those who had clinical improvement prior to angiography, there were a total of 23 patients. This was noted in 9.7% of patients who received tPA, and 21.4% of those who received TNK (p=0.043). For 8.5 patients treated with TNK rather than tPA, one patient will have spontaneous recanalization either angiographically or with clinical improvement, preventing the need for MT. Conclusions: Intravenous TNK in patients with LVOAIS reduces the need for catheter angiography and mechanical thrombectomy.

Abstract WP51: Effect Of Automated Large Vessel Occlusion Detection On Endovascular Therapy Treatment Rate: A Multi-Center Cluster Randomized Clinical Trial

Introduction: Automated Large Vessel Occlusion (LVO) detection and software-based care team integration may improve treatment times. Their effect on likelihood to perform Endovascular Thrombectomy (EVT) in LVO Acute Ischemic Stroke (AIS) patients remains undetermined. Methods: We performed a cluster randomized stepped wedge clinical trial across 4 comprehensive stroke centers in the greater Houston area from January 1st 2021 - February 24th 2022. This trial design was chosen due to the impracticality of randomizing at the patient level. An automated LVO detection and workflow manager software (Viz.AI) was implemented at the 4 hospitals in a stepped fashion, with a randomly determined order (Figure 1) . Patients were included if they were diagnosed with LVO AIS based on CT angiogram. Patients who presented during the 2-week transition period at the time of LVO detection software activation were excluded. The primary outcome was proportion of LVO AIS patients treated with EVT adjusted for age, sex and NIHSS and was determined using a mixed-effect logistic regression, with a random effect for cluster (hospital site) and fixed effect for exposure status. Results: Among 834 patients that met inclusion criteria, the median age was 68 [58-79] years, NIHSS 13 [5-20], and 50% were female. Median time from last known well to arrival was 298 [102- 754] minutes. A total of 575 patients were evaluated in the unexposed period and 259 in the exposed. In univariable analysis, there was no significant increase in the proportion of LVO AIS treated with EVT (40.5% vs. 45.6%, unexposed vs. exposed, p=0.17) . In multivariable adjusted mixed-effects model, EVT rates did not change due to software implementation [OR 1.18, p=0.45]. Discussion: In a multi-center cluster randomized trial, implementation of an automated LVO detection software with care team-wide communication did not significantly alter rates of EVT in patients with LVO AIS.

Abstract TP147: Investigating Potential Racial And Ethnic Biases In Mechanical Thrombectomy Selection For Expanded Indication Populations

Introduction: Endovascular thrombectomy (EVT) performance in clinical practice has grown substantially, including in patient groups previously excluded from clinical trials such as those with advanced age, lower Alberta Stroke Program Early CT Score (ASPECTS) and distal occlusions. However, the access and utilization of EVT in these non-randomized controlled trial (RCT) supported populations across different racial and ethnic groups remains incompletely characterized Methods: Using our prospectively maintained multi-center registry which includes four comprehensive stroke centers around the greater Houston area, we identified patients with large vessel occlusion (LVO) acute ischemic stroke (AIS). Patients were included if LVO was confirmed by non-invasive vascular imaging. The primary outcome was rate of performance of EVT in patients with low ASPECTS (0-5), advanced age (&gt; 80), and distal occlusion (M2 and beyond) by race and was determined by Fisher’s exact test. Results: Among 2,614 patients with LVO AIS, 1,239 (47%) were female, median NIHSS was 13 [interquartile range 5-20], ASPECTS was 9 [7-10]. 28% of the cohort was black, 52% white and 4% Hispanic. The most common occlusion locations were M1 MCA (34%) and M2 MCA (19%). Among the 538 patients aged &gt; 80 years old, 232 (43%) underwent EVT. There were no significant differences in the proportions of patients treated by race (43% white vs 43% black, p=1) . Among 175 patients with ASPECTS 0-5, 59 (34%) underwent EVT. There were no significant differences in the proportions of patients treated by race (44% white vs 35% black, p=0.37). Among 760 patients with occlusion of M2 and beyond, 224 (30%) underwent EVT. There were no significant differences in the proportions of patients treated by race (33% white, 29% black, p=0.28). Conclusion: In this registry from a diverse urban population, we did not identify disparities in EVT performance in patients with non-RCT supported indications by race. Further studies in other clinical settings will be important.

Abstract WP103: Machine Learning Enabled Infarct Core Estimation From CTA Predicts Functional Outcome For Endovascular Stroke Therapy

Introduction: The majority of stroke centers do not have access to advanced imaging when treating acute ischemic stroke (AIS) patients with large vessel occlusion (LVO). We previously demonstrated that a machine learning (ML) algorithm could accurately predict infarct core from CT angiography (CTA). Here, we determine the algorithm's performance to predict clinical outcomes after endovascular therapy (EVT) compared to advanced imaging. Methods: From our prospectively maintained multi-center registry, we identified consecutive LVO AIS patients screened with CTA and treated with EVT. A deep neural network ML model was trained and validated to predict infarct core size from CTA, and 24-dimensional vector embedding was extracted for each patient. The primary outcome was performance of predicting 90-day functional independence (mRS 0-3) and was determined by area under the ROC curve for two classifier models (k-nearest neighbors, k=11) that included clinical data (age, gender, NIHSS, TICI) and either the ML embeddings from CTA (KNN-CTA) or CT Perfusion infarct core estimations (RAPID, iSchemaView) (KNN-CTP). Results: Among 119 LVO AIS patients who underwent EVT, median age was 68 [IQR 57-78], 45% were female, median NIHSS was 16 [IQR 13-21], and median ASPECTS was 7 [IQR 6-8]. Average CTP-RAPID core volume was 17.9mL ±27.5 (mean±SD). 94.1% of patients achieved TICI 2b-3 and 52.1% achieved mRS 0-3 at 90 days (Table 1). Point estimates for AUROC were superior for the KNN-CTA classifier compared to the KNN-CTP (0.72 vs 0.63, p=0.025) as shown in Figures 1 and 2. Conclusion: A ML model analyzing more widely available CTA images demonstrated superior results compared to industry standard advanced imaging in predicting clinical outcomes for LVO AIS patients after EVT. These findings suggest ML-based approaches may reduce the need for advanced imaging in EVT clinical decision-making.

Endovascular treatment of acute ischemic stroke with a fully radiopaque retriever: A randomized controlled trial.

The Neurohawk retriever is a new fully radiopaque retriever. A randomized controlled non-inferiority trial was conducted to compare the Neurohawk and the Solitaire FR in terms of safety and efficacy. In order to evaluate the efficacy and safety of endovascular treatment in acute ischemic stroke (AIS) caused by intracranial atherosclerotic disease (ICAD) larger vessel occlusion (LVO), a sub-analysis was performed. Acute ischemic stroke patients aged 18-80 years with LVO in the anterior circulation were randomly assigned to undergo thrombectomy with either the Neurohawk or the Solitaire FR. The primary efficacy endpoint was successful reperfusion (mTICI 2b-3) rate by the allocated retriever. A relevant non-inferiority margin was 12.5%. Safety outcomes were symptomatic intracranial hemorrhage (sICH) and all-cause mortality within 90 days. Secondary endpoints included first-pass effect (FPE), modified FPE, and favorable outcomes at 90 days. In subgroup analysis, the patients were divided into the ICAD group and non-ICAD group according to etiology, and baseline characteristics, angiographic, and clinical outcomes were compared. A total of 232 patients were involved in this analysis (115 patients in the Neurohawk group and 117 in the Solitaire group). The rates of successful reperfusion with the allocated retriever were 88.70% in the Neurohawk group and 90.60% in the Solitaire group (95%CI of the difference, -9.74% to 5.94%; p = 0.867). There were similar results in FPE and mFPE in both groups. The rate of sICH seemed higher in the Solitaire group (13.16% vs. 7.02%, p = 0.124). All-cause mortality and favorable outcome rates were comparable as well. In subgroup analysis, 58 patients were assigned to the ICAD group and the remaining 174 to the non-ICAD group. The final successful reperfusion and favorable outcome rates showed no statistically significant differences in two groups. Mortality within 90 days was relatively lower in the ICAD group (6.90% vs. 17.24%; p = 0.054). The Neurohawk retriever is non-inferior to the Solitaire FR in the mechanical thrombectomy of large vessel occlusion-acute ischemic stroke (LVO-AIS). The sub-analysis suggested that endovascular treatment including thrombectomy with the retriever and essential rescue angioplasty is effective and safe in AIS patients with intracranial atherosclerotic disease-larger vessel occlusion (ICAD-LVO). https://clinicaltrials.gov/ct2/show/NCT04995757, number: NCT04995757.

Tenecteplase versus alteplase before mechanical thrombectomy: experience from a US healthcare system undergoing a system-wide transition of primary thrombolytic

BackgroundTenecteplase (TNK) is a genetically modified variant of alteplase (TPA) and has been established as a non-inferior alternative to TPA in acute ischemic stroke (AIS). Whether TNK exerts distinct benefits...

Single-phase CT angiography predicts ASPECTS decay and may help determine when to repeat CT before thrombectomy

ObjetivesTime is relative in large-vessel occlusion acute ischemic stroke (LVO-AIS). We aimed to evaluate the rate of inter-hospital ASPECTS decay in patients transferred from a primary (PSC) to a comprehensive stroke center (CSC); and to identify patients that should repeat computed tomography (CT) before thrombectomy. Materials and methodsThis was a retrospective cohort study of consecutive anterior circulation LVO-AIS transferred patients. The rate of ASPECTS decay was defined as (PSC-ASPECTS – CSC-ASPECTS)/hours elapsed between scans. Single-phase CT angiography (CTA) at the PSC was used to classify the collateral score. We compared patients with futile versus useful CT scan re-evaluation. ResultsWe included 663 patients, of whom 245 (37.0%) repeated CT at a CSC. The median rate of ASPECTS decay was 0.4/h (0.0-0.9). Patients excluded from thrombectomy after a CT scan repeat (n=64) had a median ASPECTS decay rate of 1.18/h (0.83-1.61). Patients with absent collateral circulation had a median rate of 1.51(0.65-2.19). The collateral score was an independent predictor of the ASPECTS decay rate (aβ = -0.35; 95%CI -0.45 - -0.19, p<0.001). Age (aOR: 1.04 95% CI 1.02-1.07, p<0.001), NIHSS (aOR: 1.11 95% CI 1.06-1.15, p<0.001), PSC ASPECTS (aOR: 0.74 95% CI 0.60-0.91, p=0.006) and the CTA collateral score (aOR: 0.14 95% CI 0.08-0.22, p<0.001) were independent predictors of the usefulness of a CT scan repeat. ConclusionsThe rate of ASPECTS decay can be predicted by the CTA collateral score, helping in the selection of patients that would benefit from repeating a CT assessment on arrival at the CSC.

Correlation between Hypoperfusion Intensity Ratio and Functional Outcome in Large-Vessel Occlusion Acute Ischemic Stroke: Comparison with Multi-Phase CT Angiography.

Background and purpose: Previous studies have shown that Hypoperfusion Intensity Ratio (HIR) derived from Perfusion Imaging (PWI) associated with collateral status in large-vessel occlusion (LVO) acute ischemic stroke (AIS) and could predict the rate of collateral flow, speed of infarct growth, and clinical outcome after endovascular treatment (EVT). We hypothesized that HIR derived from CT Perfusion (CTP) imaging could relatively accurately predict the functional outcome in LVO AIS patients receiving different types of treatment. Methods: Imaging and clinical data of consecutive patients with LVO AIS were retrospectively reviewed. Multi-phase CT angiography (mCTA) scoring was performed by 2 blinded neuroradiologists. CTP images were processed using an automatic post-processing analysis software. Correlation between the HIR and the functional outcome was calculated using the Spearman correlation. The efficacy of the HIR and the CTA collateral scores for predicting prognosis were compared. The optimal threshold of the HIR for predicting favorable functional outcome was determined using receiver operating characteristic (ROC) curve analysis. Results: 235 patients with LVO AIS were included. Patients with favorable functional outcome had lower HIR (0.1 [interquartile range (IQR), 0.1–0.2]) vs. 0.4 (IQR, 0.4–0.5)) and higher mCTA collateral scores (3 [IQR, 3–4] vs. 3 [IQR, 2–3]; p < 0.001) along with smaller infarct core volume (2.1 [IQR, 1.0–4.5]) vs. (15.2 [IQR, 5.5–39.3]; p < 0.001), larger mismatch ratio (22.9 [IQR, 11.6–45.6]) vs. (5.8 [IQR, 2.6–14]); p < 0.001), smaller ischemic volume (59.0 [IQR, 29.7–89.2]) vs. (97.5 [IQR, 68.7–142.2]; p < 0.001), and smaller final infarct volume (12.6 [IQR, 7.5–18.4]) vs. (78.9 [IQR, 44.5–165.0]; p < 0.001) than those with unfavorable functional outcome. The HIR was significantly positively correlated with the functional outcome [r = 0.852; 95% confidence interval (CI): 0.813–0.884; p < 0.0001]. The receiver operating characteristic (ROC) analysis showed that the optimal threshold for predicting a favorable functional outcome was HIR ≤ 0.3 [area under the curve (AUC) 0.968; sensitivity 88.89%; specificity 99.21%], which was higher than the mCTA collateral score [AUC 0.741; sensitivity 82.4%; specificity 48.8%]. Conclusions: HIR was associated with the functional outcome of LVO AIS patients, and the correlation coefficient was higher than mCTA collateral score. HIR outperformed mCTA collateral score in predicting functional outcome.

A Meta-analysis of Combined Aspiration Catheter and Stent Retriever versus Stent Retriever Alone for Large-Vessel Occlusion Ischemic Stroke.

The efficacy of combined aspiration catheter and stent retriever compared with stent retriever alone for the treatment of large-vessel occlusion acute ischemic stroke is unclear. Our aim was to conduct a systematic literature review and meta-analysis on several metrics of efficacy comparing aspiration catheter and stent retriever with stent retriever alone. MEDLINE and the Cochrane Library Databases were searched. Randomized controlled trials and case-control and cohort studies were included. Ten comparative studies were included detailing a combined 1495 patients with aspiration catheter and stent retriever and 1864 with stent retrievers alone. Data on first pass effect (TICI 2b/2c/3 after first pass), final successful reperfusion (modified TICI ≥2b), and 90-day functional independence (mRS ≤ 2) were collected. Meta-analysis was performed using a random-effects model. There was a pooled composite first pass effect of 40.8% (611/1495) versus 32.6% (608/1864) for aspiration catheter and stent retriever and stent retriever alone, respectively (P < .0001). Similarly, on a meta-analysis, aspiration catheter and stent retriever were associated with a higher first pass effect compared with stent retriever alone (OR = 1.63; 95% CI, 1.20-2.21; P = .002; I2 = 72%). There was no significant difference in composite rates of successful reperfusion between aspiration catheter and stent retriever (72.8%, 867/1190) and stent retriever alone (70.8%, 931/1314) (P = .27) or on meta-analysis (OR = 1.31; CI, 0.81-2.12; P = .27; I2 = 82%). No difference was found between aspiration catheter and stent retriever and stent retriever alone on 90-day functional independence (OR = 1.02; 95% CI, 0.77-1.36; P = .88; I2 = 40%). This study is limited by high interstudy heterogeneity. On meta-analysis, aspiration catheter and stent retriever are associated with a superior first pass effect compared with stent retriever alone, but they are not associated with statistically different final reperfusion or functional independence.