Abstract WP180: Novel Machine Learning Model for Prediction of Futile Recanalization in Acute Ischemic Stroke Patients With Anterior Circulation Large Vessel Occlusion
Introduction: Up to 50% of acute ischemic stroke (AIS) patients who undergo successful mechanical thrombectomy (MT) fail to achieve favorable outcomes (futile recanalization). In this study we aim to develop a machine learning (ML) model to predict futile recanalization (FR) in AIS patients who undergo MT. Methods: We used data from an ongoing large, multicenter database from 2013 to 2023. We included AIS patients treated with MT for ICA, M1, or M2 occlusion with successful recanalization (modified Thrombolysis in Cerebral Infarction [mTICI] score ≥ 2C) and procedure durations under 60 minutes. FR was defined as successful recanalization with 90-day modified Rankin Scale (mRS) 3-6. The dataset was divided into 75% for training and 25% for external validation. Using the Caret Package in R, multiple models were tested, and their performances were evaluated by the area under the curve (AUC) of receiver operating. Both baseline and pre-interventional characteristics were incorporated into the model. The selected model was then externally validated on a 25% validation dataset. Results: Among 2,546 qualified patients, FR occurred in 1,342 (52.7%). In univariate analysis, baseline characteristics were significantly different between FR and non-FR groups. The M5P model demonstrated the highest performance (AUC: 0.833; 95% CI: 0.7989-0.852; PPV: 0.8101) in comparison to other tested models such as logistic regression (AUC: 0.74), RF (AUC: 0.78), J48 (AUC: 0.78), SVM (AUC: 0.79), and GB (AUC: 0.79). The external validation of the model showed satisfactory results (AUC: 75.25; 95% CI: 70-80; PPV: 76.87). Conclusion: Utilizing clinical, pre-procedural, and imaging parameters, the M5P model can efficiently predict F) in AIS patients before attempting MT. This tool can assist neurointerventionalists in adequately choosing their MT candidates.
Abstract TP219: Outcomes and Differences by Occluded Vessel in the Endovascular Treatment for Acute Ischemic Stroke Patients With Medium Vessel Occlusion
Introduction: The outcomes of mechanical thrombectomy (MT) for patients with acute ischemic stroke (AIS) caused by medium vessel occlusions (MeVOs) in different vessels remains unknown. The aim of this study is to investigate MT outcomes in AIS patients with isolated MeVOs in different occluded vessel segments using the data from an ongoing international multicenter registry, the Stroke Thrombectomy and Aneurysm Registry (STAR). The aim of this study is to investigate MT outcomes in AIS patients with isolated MeVOs in different occluded vessel segments using the data from an ongoing international multicenter registry, the Stroke Thrombectomy and Aneurysm Registry (STAR). Methods: 110 AIS patients with MeVO who undertook MT between January 2010 and December 2022 were retrospectively investigated. MeVO was defined as isolated occlusion of the A2 or A3 (A23O) segment of the anterior cerebral artery, M3 segment of the middle cerebral artery (M3O), and P2 or P3 segment of the posterior cerebral artery (P23O). The primary outcome measure was a 90-day modified Rankin score (mRS) 0-2. The 90-day mRS 0-1, any intracranial hemorrhage, symptomatic intracranial hemorrhage, and 90-day mortality were used as secondary outcomes. Outcomes were compared between A23O, M3O, and P23O. Results: Median (interquartile range) age was 68.3 (58.4-76.0) years and 49 patients were female (46.7%). MeVO included 17 A23O (15.5%), 60 M3O (54.5%), and 33 P23O (30.0%).Compared to patients with A23O (17.7%), those with M3O (56.7%) and P23O (45.5%) had a higher proportion of 90-day mRS 0-2 (M3O, adjusted odds ratio 10.3, 95% confidence interval 1.71-62.2, p = 0.01; P23O adjusted odds ratio 8.86, 95% confidence interval 1.32-59.3, p =0.02). Other outcomes showed no significant differences. Conclusions: This study indicates A2O might be related to poorer outcomes compared to M3O and P23 in MT treatment for AIS patients due to isolated MeVO. Efforts should be aimed at improving outcomes following A23O to match those at other MeVO locations.
Abstract TP198: Factors Associated With Need for Decompressive Hemicraniectomy After Mechanical Thrombectomy in Stroke Patients
Background: Mechanical thrombectomy (MT) has significantly reduced morbidity and mortality in acute ischemic stroke (AIS). This study aims to analyze the outcomes and factors associated with decompressive hemicraniectomy (DHC) in AIS patients who underwent MT. Methods: We retrospectively analyzed data from an ongoing, multicenter database to investigate AIS patients who underwent MT for ICA, M1, or M2 occlusion. We compared clinical and procedural variables between patients who underwent DHC and those who did not. Propensity score (PS) matching between the two groups was conducted using age, sex, admission NIHSS, occluded vessel, ASPECTS, time from symptoms onset to arterial puncture, intracranial hemorrhage (ICH), and symptomatic ICH (sICH). Results: Among the 3,135 MT patients who met our inclusion criteria, 113 underwent DHC. A 1:3 propensity matching yielded a well-matched cohort of 113 in the DHC group versus 339 in the non-DHC group. The DHC group had a significantly higher rate of successful recanalization (mTICI ≥ 2C) (175 [51.6%] versus 36 [31.9%], P < 0.001) and a longer procedure duration, with a median of 30 minutes (IQR: 17-54) compared to 44 minutes (IQR: 25-78) in the non-DHC group (P = <0.001). Further comparison of patients with low ASPECTS (≤ 5) who underwent DHC (n = 36) with those who did not (n = 99) showed no significant difference in successful recanalization rates (15 [41.7%] versus 43 [43.4%], P > 0.90). However, procedure duration was significantly longer in the DHC group with a median of 29 minutes (IQR: 13-52), compared to 39 minutes (IQR: 27-86) in the non-DHC group (P = 0.02). Conclusions: Successful recanalization can help in preventing DHC in AIS patients with high ASPECTS, but not those with low ASPECTS. Procedure duration is independently related to DHC following MT, especially in low ASPECTS patients.
Abstract TP197: Impact of First-Pass Effect on Clinical Outcomes in Stroke Patients With Low Aspects
Introduction: The first-pass effect (FPE), defined as a complete or near-complete recanalization after a single pass of a mechanical thrombectomy (MT) device, has been linked to favorable clinical outcomes. However, its effectiveness in acute ischemic stroke (AIS) patients with low ASPECTS (Alberta Stroke Program Early CT Score 2-5) has not been validated. Method: We utilized data from STAR, a multicenter database of 84 centers worldwide, to conduct a retrospective, cohort study on patients who underwent MT for internal carotid artery (ICA) or M1 occlusion presenting with ASPECTS 2-5. We compared the outcomes of patients who achieved FPE (successful recanalization with an mTICI score of 2c or higher in one pass) to those who did not. The primary outcome was a 90-day favorable outcome, defined as mRS 0-3. Secondary outcomes included any intracranial hemorrhage (ICH), symptomatic ICH (sICH), and 90-day mortality. Results: Out of 10,229 patients in the STAR database, 250 patients met our inclusion criteria. Among those, 60 (24%) achieved FPE. There were no significant differences between the two groups in baseline, imaging, and procedural characteristics. FPE was significantly associated with higher odds of 90-day mRS 0-3 (adjusted odds ratio (aOR): 2.17, 95% confidence interval (CI): 1.04 - 4.20; P-value: 0.04) and lower rates of ICH (OR: 0.49, 95% CI: 0.25 - 0.93, P-value: 0.03). However, there was no significant difference in sICH rates (OR: 0.84, 95% CI: 0.31 - 2.04, P-value: 0.70). Conclusion: Achieving FPE in AIS stroke patients with low ASPECTS was associated with significantly higher rates of good functional outcomes and lower rates of ICH.
Abstract TP193: Impact of Number of Passes on Outcomes of Mechanical Thrombectomy in Stroke Patients With Low ASPECTS
Introduction: Real-world data showed that less than half of the acute ischemic stroke (AIS) patients with large vessel occlusion (LVO) presenting with low Alberta Stroke Program Early Computed Tomography Score (ASPECTS) (2-5) achieved favorable outcomes at 90 days after mechanical thrombectomy (MT). In this study, we aim to investigate the relationship between the number of MT passes at which successful recanalization is obtained and outcomes in LVO-related AIS patients with low ASPECTS. Methods: This retrospective cohort study was performed on the data from 31 thrombectomy-capable centers between 2013 to 2022. Successful recanalization was defined as modified Thrombolysis in Cerebral Ischemia Score≥ 2b. The primary outcome was a 90-day modified Rankin Scale (mRS) of 0-3. Secondary outcomes were symptomatic intracranial hemorrhage and intracranial hemorrhage within 24 hours and mortality at 90 days. Outcomes were compared among patients with unsuccessful recanalization, and successful recanalization at first, second, third, and more than four passes. Results: A total of 297 patients with a median age of 70 [IQR 59-78] years were included and 140 (47.1%) were female. In 239 (80.4%) patients, successful recanalization was achieved: 88 patients (29.6 %) with 1 pass, 59 patients (19.9 %) with 2 passes, 35 patients(11.8%) with 3 passes, and 57 patients (19.2%) with more than 4 passes. Compared to unsuccessful recanalization, successful recanalization at first pass (adjusted OR 5.25, 95% CI 1.78 - 17.1), second passes (adjusted OR 5.20, 95% CI 1.68 - 17.6), and passes 4 (adjusted OR 4.90, 95% CI 1.68 - 17.6) was related to 90-day mRS 0-3. Recanalization status and MT attempt number were not related to secondary outcomes except for 90-day mortality. Compared to unsuccessful recanalization, successful recanalization at second and third passes were inversely related to 90-day mortality (adjusted OR 0.37, 95% CI 0.14 - 0.93; adjusted OR 0.33, 95% CI 0.11 - 0.95, respectively). Conclusion: The present results indicated that successful recanalization was related to 90-day good outcome regardless of the number of MT passes but the odds of achieving favorable outcome declines with each pass.
Abstract TP187: Comparison of Balloon Guide Catheter versus Non-Balloon Guide Catheter for Mechanical Thrombectomy in Distal Medium Vessel Occlusion
Introduction: While balloon guide catheters (BGCs) enhance safety and efficacy of mechanical thrombectomy in large vessel occlusions, their impact on distal medium vessel occlusion (DMVO) remains underexplored. This study aimed to compare the outcomes of BGC vs non-BGC in DMVO thrombectomy. Methods: This retrospective study focused on DMVO cases defined as occlusions in M2-M4 middle cerebral artery, anterior cerebral artery, and posterior cerebral artery. Baseline characteristics and technical and clinical outcomes were compared between the two groups, with subgroup analysis in first-line thrombectomy techniques, including ADAPT, stent retriever, and Solumbra. First pass effect (FPE) was defined as a modified Thrombolysis in Cerebral Infarction (mTICI) score ≥ 2C after the first pass. Results: A total of 1,508 patients were included, of whom 231 (15.3%) were in the BGC group and 1,277 (84.7%) were in the Non-BGC group. The BGC group was associated with a lower mTICI score ≥ 2C (overall: 43.2% vs. 52.7%, p = 0.01; ADAPT: 42.2% vs. 57.1%, p = 0.01; Solumbra: 32.4% vs. 51.4%, p = 0.005), longer puncture to intracranial access time (overall: 15 vs. 8 min, p < 0.001; ADAPT: 17 vs. 8 min, p < 0.001; Solumbra: 12 vs. 8 min, p = 0.02), and longer puncture to recanalization time (overall: 97 vs. 35 min, p < 0.001; ADAPT: 100 vs. 28 min, p < 0.001; Solumbra: 78 vs. 46 min, p < 0.001; Stent retriever: 95 vs. 45 min, p < 0.001 ). The BGC group also had a lower FPE rate (17.4% vs. 30.7%, p = 0.03) in the Solumbra subgroup. In terms of clinical outcomes, the BGC group had a lower rate of distal embolization (overall: 8.8% vs. 14.9%, p = 0.02), but there were no significant differences in other clinical outcomes between the two groups in first-line thrombectomy techniques. Conclusions: Our findings showed that the use of BGC in DMVO had a lower mTICI score, reduced FPE rates, decreased distal embolization, and longer procedure times. Figure 1: Figure 2:
Abstract TMP88: Impact of Tandem Vertebrobasilar Occlusion on Outcome of Mechanical Thrombectomy for Basilar Artery Occlusion
Introduction: The efficacy of mechanical thrombectomy (MT) for tandem vertebrobasilar occlusion (tVBO) is not well established in patients with basilar artery occlusion (BAO). Objective: To investigate the treatment outcomes of MT in tVBO. Method: This international, multicenter, retrospective cohort included patients with MT for tVBO and isolated BAO from 2013 to 2023. The primary outcome was the 90-day modified Rankin Scale (mRS) score 0-2. Secondary outcomes included complete recanalization (modified Thrombolysis in Cerebral Ischemia [mTICI] ≥ 2C) and 90-day mortality rate. These outcomes were compared between tVBO and isolated BAO groups. Adjustment factors were age, sex, admission National Institutes of Health Stroke Scale (NIHSS), pre-morbid mRS, onset to groin duration, and intravenous tissue plasminogen activator. Results: Among 10,229 patients, 689 had BAO. Of those, 61 (9.7%) had a tVBO. Median age was 61 [IQR 53-74] years and 29 (47.5%) patients were female. Compared to isolated BAO, tVBO group had lower age (61 [53-74] versus 68 [58-79], P<0.001) and lower admission NIHSS (15 [7 - 22] versus 17 [9-26], P≤0.05). There was no significant difference in the rate of complete recanalization between the two groups (adjusted odds ratio [aOR]: 0.83; 95% CI: 0.39-1.79; P=0.60) However, the tVBO group had significantly lower odds of a favorable outcome compared to the isolated BAO group (aOR: 0.35; 95% CI: 0.13-0.83; P=0.023) and higher odds of 90-day mortality (aOR: 3.51; 95% CI: 1.59-7.85; P=0.002). Binary regression analysis revealed that age (OR 0.98; 95% CI 0.96 - 1.00; P=0.019), admission NIHSS (OR 0.90; 95% CI 0.87-0.93; P<0.001), premorbid mRS (OR 0.71; 95% CI 0.53-0.93; P=0.016), successful recanalization (OR 2.94; 95% CI 1.71-5.15; P<0.001), and tVBO (OR 0.33; 95% CI 0.11-0.86; P=0.031) were significant predictors of 90-day favorable outcome. Conclusion: tVBO was associated with poor outcomes. Further efforts should be aimed at improving outcomes for this subpopulation.
Abstract TMP61: Induced Hypertension in Acute Ischemic Stroke: Systematic Review and Meta-Analysis
Background and Objectives: It is unclear whether induced hypertension in acute ischemic stroke (AIS) may improve long-term outcomes. We conducted a systematic review and meta-analysis to compare the safety and efficacy of induced hypertension vs standard medical care in patients presenting with acute ischemic stroke within 72 hours of symptom onset. Methods: Two reviewers systematically searched PubMed using the prespecified terms “induced hypertension” or “blood pressure augmentation” plus “ischemic stroke” for clinical trials that reported functional independence (mRS 0-2) at 90 days. The safety outcome was symptomatic intracranial hemorrhage (sICH). Pooled odds ratio (OR) and 95% CI across trials were synthesized using fixed-effect model based on Mantel-Haenszel methods. Forest plots were constructed. Results: Three clinical trials with 270 AIS patients treated with induced hypertension (n=126) or standard medical care (n= 144) were included. Mean age was 66.6 years, 35.2% were women, and the mean initial NIHSS was 7.5. The rate of functional independence at 90 days was higher in patients treated with induced hypertension (70.6%) versus control (54.9%) (OR 1.88; 95% CI 1.13-3.11; p=0.01). sICH did not differ between patients treated with induced hypertension (<1%) versus control (<1%) (OR 1.03; 95% CI 0.14-7.45; p=0.98). Discussion: Among patients presenting with acute ischemic stroke with 72 hours of symptoms onset, induced hypertension resulted in better functional outcome at 90 days than standard medical care and did not increase risk of sICH. Large RCTs to test this observation are ongoing and needed to guide clinical practice.
Abstract TMP13: Prehospital Stroke Scales Are Non-Inferior to NIHSS in Prediction of Intravenous Thrombolysis Use in a Large Telestroke Network
Introduction: Recent studies report similar outcomes with antiplatelet drugs and intravenous thrombolysis (IVT) in patients with minor nondisabling ischemic stroke. These patients still meet emergent triage criteria and can increase the burden on stroke systems through prehospital stroke activation. Prehospital large vessel occlusion (LVO) scales can improve triage of LVO patients but have not been evaluated as tools to predict IVT administration. We sought to determine if common LVO scales can predict IVT use in a large academic telestroke practice. Methods: This retrospective study included all video telestroke consults performed in a large academic telestroke network from 2019-2020. Patients were excluded if they were on anticoagulation, presented beyond 4.5 hours from last known well, or family declined IVT due to goals of care. We recorded presenting NIHSS and IVT recommendations. NIHSS was used to calculate 7 LVO scales (RACE, G-FAST, FAST-ED, VAN, PASS, 3I-SS, and C-STAT). Scale performance was assessed by calculating area under curve (AUC) and compared to NIHSS total score using the DeLong test. Youden cutpoint was established for each scale and subsequently used to calculate sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy. Results: A total of 513 patients were included; 205/513 (40%) were recommended IVT. Median (IQR) NIHSS was 1 (0-3) in non-IVT patients and 6 (4-11) in IVT patients. The RACE and G-FAST scales were noninferior to the NIHSS in predicting IVT recommendation (Table 1). Conclusion: The RACE and G-FAST scales may be useful triage tools to identify patients needing emergent stroke evaluation for consideration of IVT.
Abstract 45: Poor Prediction of Stroke Mimics Using Validated Stroke Mimic Scales in a Large Academic Telestroke Network
Introduction: Telestroke enables timely and remote evaluation of patients with acute stroke syndromes. However, stroke mimics represent more than 30% of this population. Given the resources required for management of suspected acute ischemic stroke, several scales have been developed to help identify stroke mimics. Our objective was to externally validate four mimic scales (Khan Score [KS], TeleStroke Mimic Score [TS], simplified FABS [sFABS], and FABS) in a large, academic telestroke network. Methods: This is a retrospective, IRB exempt study of all patients who presented with suspected acute stroke syndromes and underwent video evaluation between 2019-2020 at a large academic telestroke network. Detailed chart review was conducted to extract both the variables needed to apply the mimic scales the final diagnosis confirmed by final imaging and discharge diagnosis (cerebral ischemic vs stroke mimic). Overall score performance was assessed by calculating area under curve (AUC). Youden cutpoint was established for each scale and used to calculate sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy. Results: A total of 1043 patients were included in the final analysis. Final diagnosis of cerebral ischemia was made in 662/1043 patients (63.5%) and stroke mimic was diagnosed in 381/1043 patients (36.5%). To predict stroke mimic, TS had the highest AUC (68.3) and PPV (73%); KS had the highest accuracy (68.6%), sensitivity (86.6%) and NPV (61.5%); and FABS had the highest specificity (54.8%) (Table 1). Conclusions: While each scale offers unique strengths, none was able to identify stroke mimics effectively enough to confidently apply in clinical practice. There remains need for significant clinical judgment to determine the likelihood of stroke mimic at presentation.