Noncontrast CT Selected Thrombectomy vs Medical Management for Late-Window Anterior Large Vessel Occlusion.

BACKGROUND AND OBJECTIVES: There is uncertainty whether patients with large vessel occlusion (LVO) presenting in the late 6-hour to 24-hour time window can be selected for endovascular therapy (EVT) by noncontrast CT (NCCT) and CT angiography (CTA) for LVO detection. We evaluated the clinical outcomes of patients selected for EVT by NCCT compared with those medically managed in the extended time window. METHODS: This multinational cohort study was conducted at 66 sites across 10 countries. Consecutive patients with proximal anterior LVO stroke selected for EVT by NCCT or medically managed and presenting within 6-24 hours of time last seen well (TSLW) from January 2014 to May 2022 were included. The primary end point was the 90-day ordinal shift in the modified Rankin Scale (mRS) score. Inverse probability treatment weighting (IPTW) and multivariable methods were used. RESULTS: Of 5,098 patients screened, 839 patients were included, with a median (interquartile range) age of 75 (64-83) years; 455 (54.2%) were women. There were 616 patients selected to undergo EVT by NCCT (73.4%) and 223 (26.6%) who were medically managed. In IPTW analyses, there was a more favorable 90-day ordinal mRS shift in patients selected by NCCT to EVT vs those who were medically managed (odds ratio [OR] 1.99, 95% CI 1.53-2.59; p < 0.001). There were higher rates of 90-day functional independence (mRS 0-2) in the EVT group (40.1% vs 18.4%, OR 3.31, 95% CI 2.11-5.20; p < 0.001). sICH was nonsignificantly higher in the EVT group (8.5% vs 1.4%, OR 3.77, 95% CI 0.72-19.7, p = 0.12). Mortality at 90 days was lower in the EVT vs MM group (23.9% vs 32.3%, OR 0.61, 95% CI 0.45-0.83, p = 0.002). DISCUSSION: In patients with proximal anterior LVO in the extended time window, there was a lower rate of disability and mortality in patients selected with NCCT and CTA to EVT compared with those who were medically managed. These findings support the use of NCCT as a simpler and more inclusive approach to patient selection in the extended window. TRIAL REGISTRATION INFORMATION: This study was registered at ClinicalTrials.gov under NCT04096248. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that for patients with proximal anterior circulation occlusion presenting with ischemic stroke from 6 to 24 hours, compared with medical management, those undergoing thrombectomy based on NCCT have reduced disability and mortality at 90 days.

Deep learning-based model for difficult transfemoral access prediction compared with human assessment in stroke thrombectomy.

BACKGROUND: In mechanical thrombectomy (MT), extracranial vascular tortuosity is among the main determinants of procedure duration and success. Currently, no rapid and reliable method exists to identify the anatomical features precluding fast and stable access to the cervical vessels. METHODS: A retrospective sample of 513 patients were included in this study. Patients underwent first-line transfemoral MT following anterior circulation large vessel occlusion stroke. Difficult transfemoral access (DTFA) was defined as impossible common carotid catheterization or time from groin puncture to first carotid angiogram >30 min. A machine learning model based on 29 anatomical features automatically extracted from head-and-neck computed tomography angiography (CTA) was developed to predict DTFA. Three experienced raters independently assessed the likelihood of DTFA on a reduced cohort of 116 cases using a Likert scale as benchmark for the model, using preprocedural CTA as well as automatic 3D vascular segmentation separately. RESULTS: Among the study population, 11.5% of procedures (59/513) presented DTFA. Six different features from the aortic, supra-aortic, and cervical regions were included in the model. Cross-validation resulted in an area under the receiver operating characteristic (AUROC) curve of 0.76 (95% CI 0.75 to 0.76) for DTFA prediction, with high sensitivity for impossible access identification (0.90, 95% CI 0.81 to 0.94). The model outperformed human assessment in the reduced cohort [F1-score (95% CI) by experts with CTA: 0.43 (0.37 to 0.50); experts with 3D segmentation: 0.50 (0.46 to 0.54); and model: 0.70 (0.65 to 0.75)]. CONCLUSIONS: A fully automatic model for DTFA prediction was developed and validated. The presented method improved expert assessment of difficult access prediction in stroke MT. Derived information could be used to guide decisions regarding arterial access for MT.

Electrical impedance measurements can identify red blood cell-rich content in acute ischemic stroke clots ex vivo associated with first-pass successful recanalization.

Background: Electrochemical impedance spectroscopy can determine characteristics such as cell density, size, and shape. The development of an electrical impedance-based medical device to estimate acute ischemic stroke (AIS) clot characteristics could improve stroke patient outcomes by informing clinical decision making. Objectives: To assess how well electrical impedance combined with machine learning identified red blood cell (RBC)-rich composition of AIS clots ex vivo, which is associated with a successfully modified first-pass effect. Methods: A total of 253 clots from 231 patients who underwent thrombectomy in 5 hospitals in France, Japan, Serbia, and Spain between February 2021 and October 2023 were analyzed in the Clotbase International Registry. Electrical impedance measurements were taken following clot retrieval by thrombectomy, followed by Martius Scarlet Blue staining. The clot components were quantified via Orbit Image Analysis, and RBC percentages were correlated with the RBC estimations made by the electrical impedance machine learning model. Results: Quantification by Martius Scarlet Blue staining identified RBCs as the major component in clots (RBCs, 37.6%; white blood cells, 5.7%; fibrin, 25.5%; platelets/other, 30.3%; and collagen, 1%). The impedance-based RBC estimation correlated well with the RBC content determined by histology, with a slope of 0.9 and Spearman's correlation of r = 0.7. Clots removed in 1 pass were significantly richer in RBCs and clots with successful recanalization in 1 pass (modified first-pass effect) were richer in RBCs as assessed using histology and impedance signature. Conclusion: Electrical impedance estimations of RBC content in AIS clots are consistent with histologic findings and may have potential for clinically relevant parameters.

Modeling Robotic-Assisted Mechanical Thrombectomy Procedures with the CorPath GRX Robot: The Core-Flow Study.

BACKGROUND AND PURPOSE: Endovascular robotic devices may enable experienced neurointerventionalists to remotely perform endovascular thrombectomy. This study aimed to assess the feasibility, safety, and efficacy of robot-assisted endovascular thrombectomy compared with manual procedures by operators with varying levels of experience, using a 3D printed neurovascular model. MATERIALS AND METHODS: M1 MCA occlusions were simulated in a 3D printed neurovascular model, linked to a CorPath GRX robot in a biplane angiography suite. Four interventionalists performed manual endovascular thrombectomy (n = 45) and robot-assisted endovascular thrombectomy (n = 37) procedures. The outcomes included first-pass recanalization (TICI 2c-3), the number and size of generated distal emboli, and procedural length. RESULTS: A total of 82 experimental endovascular thrombectomies were conducted. A nonsignificant trend favoring the robot-assisted endovascular thrombectomy was observed in terms of final recanalization (89.2% versus manual endovascular thrombectomy, 71.1%; P = .083). There were no differences in total mean emboli count (16.54 [SD, 15.15] versus 15.16 [SD, 16.43]; P = .303). However, a higher mean count of emboli of > 1 mm was observed in the robot-assisted endovascular thrombectomy group (1.08 [SD, 1.00] versus 0.49 [SD, 0.84]; P = .001) compared with manual endovascular thrombectomy. The mean procedural length was longer in robot-assisted endovascular thrombectomy (6.43 [SD, 1.71] minutes versus 3.98 [SD, 1.84] minutes; P < .001). Among established neurointerventionalists, previous experience with robotic procedures did not influence recanalization (95.8% were considered experienced; 76.9% were considered novices; P = .225). CONCLUSIONS: In a 3D printed neurovascular model, robot-assisted endovascular thrombectomy has the potential to achieve recanalization rates comparable with those of manual endovascular thrombectomy within competitive procedural times. Optimization of the procedural setup is still required before implementation in clinical practice.

Pre-hospital stroke monitoring past, present, and future: a perspective.

Integrated brain-machine interface signifies a transformative advancement in neurological monitoring and intervention modalities for events such as stroke, the leading cause of disability. Historically, stroke management relied on clinical evaluation and imaging. While today's stroke landscape integrates artificial intelligence for proactive clinical decision-making, mainly in imaging and stroke detection, it depends on clinical observation for early detection. Cardiovascular monitoring and detection systems, which have become standard throughout healthcare and wellness settings, provide a model for future cerebrovascular monitoring and detection. This commentary reviews the progression of continuous stroke monitoring, spotlighting contemporary innovations and prospective avenues, and emphasizes the influential roles of cutting-edge technologies in shaping stroke care.

Safety and efficacy of early carotid artery stenting in patients with symptomatic stenosis.

BACKGROUND: Symptomatic carotid artery stenosis is a significant contributor to ischemic strokes. Carotid artery stenting (CAS) is usually indicated for secondary stroke prevention. This study evaluates the safety and efficacy of CAS performed within a short time frame from symptom onset. METHODS: We conducted a single-center, retrospective study of consecutive patients who underwent CAS for symptomatic carotid stenosis within eight days of symptom onset from July 2019 to January 2022. Data on demographics, medical history, procedural details, and follow-up outcomes were analyzed. The primary outcome measure was the recurrence of the stroke within the first month post-procedure. Secondary outcomes included mortality, the rate of intra-procedural complications, and hyperperfusion syndrome. RESULTS: We included 93 patients with a mean age of 71.7 ± 11.7 years. The median time from symptom onset to CAS was 96 h. The rate of stroke recurrence was 5.4% in the first month, with a significant association between the number of stents used and increased recurrence risk. Mortality within the first month was 3.2%, with an overall mortality rate of 11.8% after a median follow-up of 19 months. Intra-procedural complications were present in five (5.4%) cases and were related to the number of stents used (p = 0.002) and post-procedural angioplasty (p = 0.045). Hyperperfusion syndrome occurred in 3.2% of cases. CONCLUSION: Early CAS within the high-risk window post-symptom onset is a viable secondary stroke prevention strategy in patients with symptomatic carotid artery stenosis. The procedure rate of complication is acceptable, with a low recurrence of stroke. However, further careful selection of patients for this procedural strategy is crucial to optimize outcomes.

Acute management of cerebral venous thrombosis: Indications, technique, and outcome of endovascular treatment in two high-volume centers.

INTRODUCTION: After several uncontrolled studies and one randomized clinical trial, there is still uncertainty regarding the role of endovascular treatment (EVT) in cerebral venous thrombosis (CVT). This study aims to describe and assess different acute management strategies in the treatment of CVT. METHODS: We performed a retrospective analysis of an international two-center registry of CVT patients admitted since 2019. Good outcome was defined as a return to baseline modified Rankin scale at three months. We described and compared EVT versus no-EVT patients. RESULTS: We included 61 patients. Only one did not receive systemic anticoagulation. EVT was performed in 13/61 (20%) of the cases, with a median time from diagnosis to puncture of 4.5 h (1.25-28.5). EVT patients had a higher median baseline NIHSS [6 (IQR 2-17) vs 0 (0-2.7), p = 0.002)] and a higher incidence of intracerebral hemorrhage (53.8% vs 20.3%, p = 0.03). Recanalization was achieved in 10/13 (77%) patients. Thrombectomy was performed in every case with angioplasty in 7 out of 12 patients and stenting in 3 cases. No postprocedural complication was reported. An improvement of the median NIHSS from baseline to discharge [6 (2-17) vs 1(0-3.75); p < 0.001] was observed in EVT group. A total of 31/60 patients (50.8%) had good outcomes. Adjusting to NIHSS and ICH, EVT had a non-significant increase in the odds of a good outcome [aOR 1.42 (95%CI 0.73-2.8, p = 0.307)]. CONCLUSIONS: EVT in combination with anticoagulation was safe in acute treatment of CVT as suggested by NIHSS improvement. Selected patients may benefit from this treatment.

PRERISK: A Personalized, Artificial Intelligence-Based and Statistically-Based Stroke Recurrence Predictor for Recurrent Stroke.

BACKGROUND: Predicting stroke recurrence for individual patients is difficult, but individualized prediction may improve stroke survivors' engagement in self-care. We developed PRERISK: a statistical and machine learning classifier to predict individual risk of stroke recurrence. METHODS: We analyzed clinical and socioeconomic data from a prospectively collected public health care-based data set of 41 975 patients admitted with stroke diagnosis in 88 public health centers over 6 years (2014-2020) in Catalonia-Spain. A new stroke diagnosis at least 24 hours after the index event was considered as a recurrent stroke, which was considered as our outcome of interest. We trained several supervised machine learning models to provide individualized risk over time and compared them with a Cox regression model. Models were trained to predict early, late, and long-term recurrence risk, within 90, 91 to 365, and >365 days, respectively. C statistics and area under the receiver operating characteristic curve were used to assess the accuracy of the models. RESULTS: Overall, 16.21% (5932 of 36 114) of patients had stroke recurrence during a median follow-up of 2.69 years. The most powerful predictors of stroke recurrence were time from previous stroke, Barthel Index, atrial fibrillation, dyslipidemia, age, diabetes, and sex, which were used to create a simplified model with similar performance, together with modifiable vascular risk factors (glycemia, body mass index, high blood pressure, cholesterol, tobacco dependence, and alcohol abuse). The areas under the receiver operating characteristic curve were 0.76 (95% CI, 0.74-0.77), 0.60 (95% CI, 0.58-0.61), and 0.71 (95% CI, 0.69-0.72) for early, late, and long-term recurrence risk, respectively. The areas under the receiver operating characteristic curve of the Cox risk class probability were 0.73 (95% CI, 0.72-0.75), 0.59 (95% CI, 0.57-0.61), and 0.67 (95% CI, 0.66-0.70); machine learning approaches (random forest and AdaBoost) showed statistically significant improvement (P<0.05) over the Cox model for the 3 recurrence time periods. Stroke recurrence curves can be simulated for each patient under different degrees of control of modifiable factors. CONCLUSIONS: PRERISK is a novel approach that provides a personalized and fairly accurate risk prediction of stroke recurrence over time. The model has the potential to incorporate dynamic control of risk factors.

Anesthetic management for large vessel occlusion acute ischemic stroke with tandem lesions.

BACKGROUND: Endovascular therapy (EVT) stands as an established and effective intervention for acute ischemic stroke in patients harboring tandem lesions (TLs). However, the optimal anesthetic strategy for EVT in TL patients remains unclear. This study aims to evaluate the impact of distinct anesthetic techniques on outcomes in acute ischemic stroke patients presenting with TLs. METHODS: Patient-level data, encompassing cases from 16 diverse centers, were aggregated for individuals with anterior circulation TLs treated between January 2015 and December 2020. A stratification based on anesthetic technique was conducted to distinguish between general anesthesia (GA) and procedural sedation (PS). Multivariable logistic regression models were built to discern the association between anesthetic approach and outcomes, including the favorable functional outcome defined as 90-day modified Rankin Score (mRS) of 0-2, ordinal shift in mRS, symptomatic intracranial hemorrhage (sICH), any hemorrhage, successful recanalization (modified Thrombolysis In Cerebral Infarction (mTICI) score ≥2b), excellent recanalization (mTICI 3), first pass effect (FPE), early neurological improvement (ENI), door-to-groin and recanalization times, intrahospital mortality, and 90-day mortality. RESULTS: Among 691 patients from 16 centers, 595 patients (GA 38.7%, PS 61.3%) were included in the final analysis. There were no significant differences noted in the door-to-groin time (80 (46-117.5) mins vs 54 (21-100), P=0.607) and groin to recanalization time (59 (39.5-85.5) mins vs 54 (38-81), P=0.836) among the groups. The odds of a favorable functional outcome (36.6% vs 52.6%; adjusted OR (aOR) 0.56, 95% CI 0.38 to 0.84, P=0.005) and a favorable shift in the 90-day mRS (aOR 0.71, 95% CI 0.51 to 0.99, P=0.041) were lower in the GA group. No differences were noted for sICH (3.9% vs 4.7%, P=0.38), successful recanalization (89.1% vs 86.5%, P=0.13), excellent recanalization (48.5% vs 50.3%, P=0.462), FPE (53.6% vs 63.4%, P=0.05), ENI (38.9% vs 38.8%, P=0.138), and 90-day mortality (20.3% vs 16.3%, P=0.525). An interaction was noted for favorable functional outcome between the type of anesthesia and the baseline Alberta Stroke Program Early CT Score (ASPECTS) (P=0.033), degree of internal carotid artery (ICA) stenosis (P<0.001), and ICA stenting (P<0.001), and intraparenchymal hematoma between the type of anesthesia and intravenous thrombolysis (P=0.019). In a subgroup analysis, PS showed better functional outcomes in patients with age ≤70 years, National Institutes of Health Stroke Scale (NIHSS) score <15, and acute ICA stenting. CONCLUSIONS: Our findings suggest that the preference for PS not only aligns with comparable procedural safety but is also associated with superior functional outcomes. These results prompt a re-evaluation of current anesthesia practices in EVT, urging clinicians to consider patient-specific characteristics when determining the optimal anesthetic strategy for this patient population.

Radial Versus Femoral Access for Mechanical Thrombectomy in Patients With Stroke: A Noninferiority Randomized Clinical Trial.

BACKGROUND: Transfemoral access is predominantly used for mechanical thrombectomy in patients with stroke with a large vessel occlusion. Following the interventional cardiology guidelines, routine transradial access has been proposed as an alternative, although its safety and efficacy remain controversial. We aim to explore the noninferiority of radial access in terms of final recanalization. METHODS: The study was an investigator-initiated, single-center, evaluator-blinded, noninferiority randomized clinical trial. Patients with stroke undergoing mechanical thrombectomy, with a patent femoral artery and a radial artery diameter ≥2.5 mm, were randomly assigned (1:1) to either transradial (60 patients) or transfemoral access (60 patients). The primary binary outcome was the successful recanalization (expanded Treatment in Cerebral Ischemia score, 2b-3) assigned by blinded evaluators. We established a noninferiority margin of -13.2%, considering an acceptable reduction of 15% in the expected recanalization rates. RESULTS: From September 2021 to July 2023, 120 patients were randomly assigned and 116 (58 transradial access and 58 transfemoral access) with confirmed intracranial occlusion on the initial angiogram were included in the intention-to-treat analysis. Successful recanalization was achieved in 51 (87.9%) patients assigned to transfemoral access and in 56/58 (96.6%) patients assigned to transradial (adjusted 1 side risk difference [RD], -5.0% [95% CI, -6.61% to +13.1%]) showing noninferiority of transradial access. Median time from angiosuite arrival to first pass (femoral, 30 [interquartile range, 25-37] minutes versus radial: 41 [interquartile range, 33-62] minutes; P<0.001) and from angiosuite arrival to recanalization (femoral: 42 (IQR, 28-74) versus radial: 59.5 (IQR, 44-81) minutes; P<0.050) were longer in the transradial access group. Both groups presented 1 severe access complication and there was no difference in the rate of access conversion: transradial 7 (12.1%) versus transfemoral 5 (8.6%) (P=0.751). CONCLUSIONS: Among patients who underwent mechanical thrombectomy, transradial access was noninferior to transfemoral access in terms of final recanalization. Procedural delays may favor transfemoral access as the default first-line approach. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05225636.

Radial Versus Femoral Access for Mechanical Thrombectomy in Patients With Stroke: A Noninferiority Randomized Clinical Trial.

BACKGROUND: Transfemoral access is predominantly used for mechanical thrombectomy in patients with stroke with a large vessel occlusion. Following the interventional cardiology guidelines, routine transradial access has been proposed as an alternative, although its safety and efficacy remain controversial. We aim to explore the noninferiority of radial access in terms of final recanalization. METHODS: The study was an investigator-initiated, single-center, evaluator-blinded, noninferiority randomized clinical trial. Patients with stroke undergoing mechanical thrombectomy, with a patent femoral artery and a radial artery diameter ≥2.5 mm, were randomly assigned (1:1) to either transradial (60 patients) or transfemoral access (60 patients). The primary binary outcome was the successful recanalization (expanded Treatment in Cerebral Ischemia score, 2b-3) assigned by blinded evaluators. We established a noninferiority margin of -13.2%, considering an acceptable reduction of 15% in the expected recanalization rates. RESULTS: From September 2021 to July 2023, 120 patients were randomly assigned and 116 (58 transradial access and 58 transfemoral access) with confirmed intracranial occlusion on the initial angiogram were included in the intention-to-treat analysis. Successful recanalization was achieved in 51 (87.9%) patients assigned to transfemoral access and in 56/58 (96.6%) patients assigned to transradial (adjusted 1 side risk difference [RD], -5.0% [95% CI, -6.61% to +13.1%]) showing noninferiority of transradial access. Median time from angiosuite arrival to first pass (femoral, 30 [interquartile range, 25-37] minutes versus radial: 41 [interquartile range, 33-62] minutes; P<0.001) and from angiosuite arrival to recanalization (femoral: 42 (IQR, 28-74) versus radial: 59.5 (IQR, 44-81) minutes; P<0.050) were longer in the transradial access group. Both groups presented 1 severe access complication and there was no difference in the rate of access conversion: transradial 7 (12.1%) versus transfemoral 5 (8.6%) (P=0.751). CONCLUSIONS: Among patients who underwent mechanical thrombectomy, transradial access was noninferior to transfemoral access in terms of final recanalization. Procedural delays may favor transfemoral access as the default first-line approach. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05225636.

Clinico-radiological features of intracranial atherosclerosis-related large vessel occlusion prior to endovascular treatment.

The identification of large vessel occlusion with underlying intracranial atherosclerotic disease (ICAS-LVO) before endovascular treatment (EVT) continues to be a challenge. We aimed to analyze baseline clinical-radiological features associated with ICAS-LVO that could lead to a prompt identification. We performed a retrospective cross-sectional study of consecutive patients with stroke treated with EVT from January 2020 to April 2022. We included anterior LVO involving intracranial internal carotid artery and middle cerebral artery. We analyzed baseline clinical and radiological variables associated with ICAS-LVO and evaluated the diagnostic value of a multivariate logistic regression model to identify ICAS-LVO before EVT. ICAS-LVO was defined as presence of angiographic residual stenosis or a trend to re-occlusion during EVT procedure. A total of 338 patients were included in the study. Of them, 28 patients (8.3%) presented with ICAS-LVO. After adjusting for confounders, absence of atrial fibrillation (OR 9.33, 95% CI 1.11-78.42; p = 0.040), lower hypoperfusion intensity ratio (HIR [Tmax > 10 s/Tmax > 6 s ratio], (OR 0.69, 95% CI 0.50-0.95; p = 0.025), symptomatic intracranial artery calcification (IAC, OR .15, 95% CI 1.64-26.42, p = 0.006), a more proximal occlusion (ICA, MCA-M1: OR 4.00, 95% CI 1.23-13.03; p = 0.021), and smoking (OR 2.91, 95% CI 1.08-7.90; p = 0.035) were associated with ICAS-LVO. The clinico-radiological model showed an overall well capability to identify ICAS-LVO (AUC = 0.88, 95% CI 0.83-0.94; p < 0.001). In conclusion, a combination of clinical and radiological features available before EVT can help to identify an ICAS-LVO. This approach could be useful to perform a rapid assessment of underlying etiology and suggest specific pathophysiology-based measures. Prospective studies are needed to validate these findings in other populations.

Endovascular Thrombectomy Treatment Effect in Direct vs Transferred Patients With Large Ischemic Strokes: A Prespecified Analysis of the SELECT2 Trial.

Importance: Patients with large ischemic core stroke have poor clinical outcomes and are frequently not considered for interfacility transfer for endovascular thrombectomy (EVT). Objective: To assess EVT treatment effects in transferred vs directly presenting patients and to evaluate the association between transfer times and neuroimaging changes with EVT clinical outcomes. Design, Setting, and Participants: This prespecified secondary analysis of the SELECT2 trial, which evaluated EVT vs medical management (MM) in patients with large ischemic stroke, evaluated adults aged 18 to 85 years with acute ischemic stroke due to occlusion of the internal carotid or middle cerebral artery (M1 segment) as well as an Alberta Stroke Program Early CT Score (ASPECTS) of 3 to 5, core of 50 mL or greater on imaging, or both. Patients were enrolled between October 2019 and September 2022 from 31 EVT-capable centers in the US, Canada, Europe, Australia, and New Zealand. Data were analyzed from August 2023 to January 2024. Interventions: EVT vs MM. Main Outcomes and Measures: Functional outcome, defined as modified Rankin Scale (mRS) score at 90 days with blinded adjudication. Results: A total of 958 patients were screened and 606 patients were excluded. Of 352 enrolled patients, 145 (41.2%) were female, and the median (IQR) age was 66.5 (58-75) years. A total of 211 patients (59.9%) were transfers, while 141 (40.1%) presented directly. The median (IQR) transfer time was 178 (136-230) minutes. The median (IQR) ASPECTS decreased from the referring hospital (5 [4-7]) to an EVT-capable center (4 [3-5]). Thrombectomy treatment effect was observed in both directly presenting patients (adjusted generalized odds ratio [OR], 2.01; 95% CI, 1.42-2.86) and transferred patients (adjusted generalized OR, 1.50; 95% CI, 1.11-2.03) without heterogeneity (P for interaction = .14). Treatment effect point estimates favored EVT among 82 transferred patients with a referral hospital ASPECTS of 5 or less (44 received EVT; adjusted generalized OR, 1.52; 95% CI, 0.89-2.58). ASPECTS loss was associated with numerically worse EVT outcomes (adjusted generalized OR per 1-ASPECTS point loss, 0.89; 95% CI, 0.77-1.02). EVT treatment effect estimates were lower in patients with transfer times of 3 hours or more (adjusted generalized OR, 1.15; 95% CI, 0.73-1.80). Conclusions and Relevance: Both directly presenting and transferred patients with large ischemic stroke in the SELECT2 trial benefited from EVT, including those with low ASPECTS at referring hospitals. However, the association of EVT with better functional outcomes was numerically better in patients presenting directly to EVT-capable centers. Prolonged transfer times and evolution of ischemic change were associated with worse EVT outcomes. These findings emphasize the need for rapid identification of patients suitable for transfer and expedited transport. Trial Registration: ClinicalTrials.gov Identifier: NCT03876457.

Influence of vascular imaging acquisition at local stroke centers on workflows in the drip-n-ship model: a RACECAT post hoc analysis.

BACKGROUND: The influence of vascular imaging acquisition on workflows at local stroke centers (LSCs) not capable of performing thrombectomy in patients with a suspected large vessel occlusion (LVO) stroke remains uncertain. We analyzed the impact of performing vascular imaging (VI+) or not (VI- at LSC arrival on variables related to workflows using data from the RACECAT Trial. OBJECTIVE: To compare workflows at the LSC among patients enrolled in the RACECAT Trial with or without VI acquisition. METHODS: We included patients with a diagnosis of ischemic stroke who were enrolled in the RACECAT Trial, a cluster-randomized trial that compared drip-n-ship versus mothership triage paradigms in patients with suspected acute LVO stroke allocated at the LSC. Outcome measures included time metrics related to workflows and the rate of interhospital transfers and thrombectomy among transferred patients. RESULTS: Among 467 patients allocated to a LSC, vascular imaging was acquired in 277 patients (59%), of whom 198 (71%) had a LVO. As compared with patients without vascular imaging, patients in the VI+ group were transferred less frequently as thrombectomy candidates to a thrombectomy-capable center (58% vs 74%, P=0.004), without significant differences in door-indoor-out time at the LSC (median minutes, VI+ 78 (IQR 69-96) vs VI- 76 (IQR 59-98), P=0.6). Among transferred patients, the VI+ group had higher rate of thrombectomy (69% vs 55%, P=0.016) and shorter door to puncture time (median minutes, VI+ 41 (IQR 26-53) vs VI- 54 (IQR 40-70), P<0.001). CONCLUSION: Among patients with a suspected LVO stroke initially evaluated at a LSC, vascular imaging acquisition might improve workflow times at thrombectomy-capable centers and reduce the rate of futile interhospital transfers. These results deserve further evaluation and should be replicated in other settings and geographies.

Cost-utility of direct transfer to angiography suite (DTAS) bypassing conventional imaging for patients with acute ischemic stroke in Spain: results from the ANGIOCAT trial.

BACKGROUND: The ANGIOCAT trial showed a clinical benefit of direct to angiography suite (DTAS) for patients with large vessel occlusion (LVO) stroke admitted within 6 hours after symptom onset in decreased hospital workflow time and improved clinical outcome. However, the impact of DTAS implementation on hospital costs is unknown. This economic evaluation aims to assess the cost-utility of DTAS from the provider (hospital) perspective. METHODS: A cost-utility analysis was applied to compare DTAS with the standard direct to CT (DTCT) suite approach using direct cost and health outcomes data. The time horizon was 90 days. One-way sensitivity analysis as well as probabilistic sensitivity analysis was performed, varying the model parameters by ±25%. Measures included costs, quality-adjusted life years, and incremental cost-effectiveness ratios. Health outcomes, classified according to the modified Rankin Scale, were obtained from the ANGIOCAT trial. Respective utilities were obtained from the literature. RESULTS: DTAS is the dominant strategy. The incremental cost-effectiveness ratio is -€89 110 (-$97 600) with cost saving per patient of -€2848 (-$3120). The improved clinical outcome is directly related with a decrease in costs for the hospital, mainly due to the decrease in costs of hospital stay, improved clinical outcome and fewer complications. CONCLUSIONS: For patients with LVO admitted within 6 hours after symptom onset, the DTAS not only improves clinical outcome but also decreases the costs (dominant option) compared with the standard DTCT. Multicentric international randomized clinical trials are ongoing to determine the replicability of our findings.

Antithrombotic regimen in emergent carotid stenting for acute ischemic stroke due to tandem occlusion: a meta-analysis of aggregate data.

BACKGROUND: The periprocedural antithrombotic regimen might affect the risk-benefit profile of emergent carotid artery stenting (eCAS) in patients with acute ischemic stroke (AIS) due to tandem lesions, especially after intravenous thrombolysis. We conducted a systematic review and meta-analysis to evaluate the safety and efficacy of antithrombotics following eCAS. METHODS: We followed PRISMA guidelines and searched MEDLINE, Embase, and Scopus from January 1, 2004 to November 30, 2022 for studies evaluating eCAS in tandem occlusion. The primary endpoint was 90-day good functional outcome. Secondary outcomes were symptomatic intracerebral hemorrhage, in-stent thrombosis, delayed stent thrombosis, and successful recanalization. Meta-analysis of proportions and meta-analysis of odds ratios were implemented. RESULTS: 34 studies with 1658 patients were included. We found that the use of no antiplatelets (noAPT), single antiplatelet (SAPT), dual antiplatelets (DAPT), or glycoprotein IIb/IIIa inhibitors (GPI) yielded similar rates of good functional outcomes, with a marginal benefit of GPI over SAPT (OR 1.88, 95% CI 1.05 to 3.35, Pheterogeneity=0.31). Sensitivity analysis and meta-regression excluded a significant impact of intravenous thrombolysis and Alberta Stroke Program Early CT Score (ASPECTS). We observed no increase in symptomatic intracerebral hemorrhage (sICH) with DAPT or GPI compared with noAPT or SAPT. We also found similar rates of delayed stent thrombosis across groups, with acute in-stent thrombosis showing marginal, non-significant benefits from GPI and DAPT over SAPT and noAPT. CONCLUSIONS: In AIS due to tandem occlusion, the periprocedural antithrombotic regimen of eCAS seems to have a marginal effect on good functional outcome. Overall, high intensity antithrombotic therapy may provide a marginal benefit on good functional outcome and carotid stent patency without a significant increase in risk of sICH.

No-reflow phenomenon in stroke patients: A systematic literature review and meta-analysis of clinical data.

BACKGROUND: The no-reflow phenomenon refers to the absence of microvascular reperfusion despite macrovascular reperfusion. AIM: The aim of this analysis was to summarize the available clinical evidence on no-reflow in patients with acute ischemic stroke. METHODS: A systematic literature review and a meta-analysis of clinical data on definition, rates, and impact of the no-reflow phenomenon after reperfusion therapy was carried out. A predefined research strategy was formulated according to the Population, Intervention, Comparison, and Outcome (PICO) model and was used to screen for articles in PubMed, MEDLINE, and Embase up to 8 September 2022. Whenever possible, quantitative data were summarized using a random-effects model. RESULTS: Thirteen studies with a total of 719 patients were included in the final analysis. Most studies (n = 10/13) used variations of the Thrombolysis in Cerebral Infarction scale to evaluate macrovascular reperfusion, whereas microvascular reperfusion and no-reflow were mostly assessed on perfusion maps (n = 9/13). In one-third of stroke patients with successful macrovascular reperfusion (29%, 95% confidence interval (CI), 21-37%), the no-reflow phenomenon was observed. Pooled analysis showed that no-reflow was consistently associated with reduced rates of functional independence (odds ratio (OR), 0.21, 95% CI, 0.15-0.31). CONCLUSION: The definition of no-reflow varied substantially across studies, but it appears to be a common phenomenon. Some of the no-reflow cases may simply represent remaining vessel occlusions, and it remains unclear whether no-reflow is an epiphenomenon of the infarcted parenchyma or causes infarction. Future studies should focus on standardizing the definition of no-reflow with more consistent definitions of successful macrovascular reperfusion and experimental set-ups that could detect the causality of the observed findings.

Impact of stent-retriever tip design on distal embolization during mechanical thrombectomy: a randomized in vitro evaluation.

BACKGROUND: Repeated number of passes, clot fragmentation, and distal embolization during mechanical thrombectomy (MT) lead to worse clinical outcomes in acute ischemic stroke. This study aimed to assess the recanalization and embolic outcomes of different stent-retrievers (SRs): open-tip SR (Solitaire X 6×40 mm), closed-tip SR (EmboTrap II 5×33 mm), and filter-tip SR (NeVa NET 5.5×37 mm). METHODS: Stiff-friable clot analogs were used to create middle cerebral artery (M1-MCA) occlusions in a benchtop model. After occlusion, experiments were randomized into one of the three treatment arms. The thrombectomy technique consisted of retrieving the SR into a balloon guide catheter under proximal flow arrest and continuous aspiration. A total of 150 single-attempt cases were performed (50 cases/treatment arm). Distal emboli (>100 µm) were collected and analyzed after each experiment. RESULTS: Filter-tip SR achieved a non-significantly higher first-pass recanalization rate than open-tip SR and closed-tip SR (66% vs 48% vs 44%; P=0.064). Filter-tip SR prevented clot fragments>1 mm from embolizing distal territories in 44% of cases, compared with 16% in open-tip SR and 20% in closed-tip (P=0.003). There were no significant differences between treatment arms in terms of total emboli count (open-tip=19.2±13.1, closed-tip=19.1±10.7, filter-tip=17.2±13.0; P=0.660). Nonetheless, the number of large emboli (>1 mm) and total area of emboli were significantly lower in the filter-tip arm (n=0.88±1.2, A=2.06±1.85 mm2) than in the closed-tip arm (n=2.34±3.38, A=4.06±4.80 mm2; P<0.05). CONCLUSIONS: When facing fragment-prone clots, the filter-tip SR significantly reduces the number of large clots (>1 mm) that embolize distally during an MT procedure, which in turn may increase the chances of first-pass complete recanalization.

Effect of Bridging Thrombolysis on the Efficacy of Stent Retriever Thrombectomy Techniques : Insights from the SWIFT-DIRECT trial.

BACKGROUND: There are little available data regarding the influence of intravenous thrombolysis (IVT) on the efficacy of different first line endovascular treatment (EVT) techniques. METHODS: We used the dataset of the SWIFT-DIRECT trial which randomized 408 patients to IVT + EVT or EVT alone at 48 international sites. The protocol required the use of a stent retriever (SR), but concomitant use of a balloon guide catheter (BGC) and/or distal aspiration (DA) catheter was left to the discretion of the operators. Four first line techniques were applied in the study population: SR, SR + BGC, SR + DA, SR + DA + BGC. To assess whether the effect of allocation to IVT + EVT versus EVT alone was modified by the first line technique, interaction models were fitted for predefined outcomes. The primary outcome was first pass mTICI 2c­3 reperfusion (FPR). RESULTS: This study included 385 patients of whom 172 were treated with SR + DA, 121 with SR + DA + BGC, 57 with SR + BGC and 35 with SR. There was no evidence that the effect of IVT + EVT versus EVT alone would be modified by the choice of first line technique; however, allocation to IVT + EVT increased the odds of FPR by a factor of 1.68 (95% confidence interval, CI 1.11-2.54). CONCLUSION: This post hoc analysis does not suggest treatment effect heterogeneity of IVT + EVT vs EVT alone in different stent retriever techniques but provides evidence for increased FPR if bridging IVT is administered before stent retriever thrombectomy.

A multitrait genetic study of hemostatic factors and hemorrhagic transformation after stroke treatment.

BACKGROUND: Thrombolytic recombinant tissue plasminogen activator (r-tPA) treatment is the only pharmacologic intervention available in the ischemic stroke acute phase. This treatment is associated with an increased risk of intracerebral hemorrhages, known as hemorrhagic transformations (HTs), which worsen the patient's prognosis. OBJECTIVES: To investigate the association between genetically determined natural hemostatic factors' levels and increased risk of HT after r-tPA treatment. METHODS: Using data from genome-wide association studies on the risk of HT after r-tPA treatment and data on 7 hemostatic factors (factor [F]VII, FVIII, von Willebrand factor [VWF], FXI, fibrinogen, plasminogen activator inhibitor-1, and tissue plasminogen activator), we performed local and global genetic correlation estimation multitrait analyses and colocalization and 2-sample Mendelian randomization analyses between hemostatic factors and HT. RESULTS: Local correlations identified a genomic region on chromosome 16 with shared covariance: fibrinogen-HT, P = 2.45 × 10-11. Multitrait analysis between fibrinogen-HT revealed 3 loci that simultaneously regulate circulating levels of fibrinogen and risk of HT: rs56026866 (PLXND1), P = 8.80 × 10-10; rs1421067 (CHD9), P = 1.81 × 10-14; and rs34780449, near ROBO1 gene, P = 1.64 × 10-8. Multitrait analysis between VWF-HT showed a novel common association regulating VWF and risk of HT after r-tPA at rs10942300 (ZNF366), P = 1.81 × 10-14. Mendelian randomization analysis did not find significant causal associations, although a nominal association was observed for FXI-HT (inverse-variance weighted estimate [SE], 0.07 [-0.29 to 0.00]; odds ratio, 0.87; 95% CI, 0.75-1.00; raw P = .05). CONCLUSION: We identified 4 shared loci between hemostatic factors and HT after r-tPA treatment, suggesting common regulatory mechanisms between fibrinogen and VWF levels and HT. Further research to determine a possible mediating effect of fibrinogen on HT risk is needed.