Clinical relevance of intracranial hemorrhage after thrombectomy versus medical management for large core infarct: a secondary analysis of the SELECT2 randomized trial.

BACKGROUND: The incidence of intracerebral hemorrhage (ICH) and its effect on the outcomes after endovascular thrombectomy (EVT) for patients with large core infarcts have not been well-characterized. METHODS: SELECT2 trial follow-up imaging was evaluated using the Heidelberg Bleeding Classification (HBC) to define hemorrhage grade. The association of ICH with clinical outcomes and treatment effect was examined. RESULTS: Of 351 included patients, 194 (55%) and 189 (54%) demonstrated intracranial and intracerebral hemorrhage, respectively, with a higher incidence in EVT (134 (75%) and 130 (73%)) versus medical management (MM) (60 (35%) and 59 (34%), both P<0.001). Hemorrhagic infarction type 1 (HBC=1a) and type 2 (HBC=1b) accounted for 93% of all hemorrhages. Parenchymal hematoma (PH) type 1 (HBC=1c) and type 2 (HBC=2) were observed in 1 (0.6%) EVT-treated and 4 (2.2%) MM patients. Symptomatic ICH (sICH) (SITS-MOST definition) was seen in 0.6% EVT patients and 1.2% MM patients. No trend for ICH with core volumes (P=0.10) or Alberta Stroke Program Early CT Score (ASPECTS) (P=0.74) was observed. Among EVT patients, the presence of any ICH did not worsen clinical outcome (modified Rankin Scale (mRS) at 90 days: 4 (3-6) vs 4 (3-6); adjusted generalized OR 1.00, 95% CI 0.68 to 1.47, P>0.99) or modify EVT treatment effect (Pinteraction=0.77). CONCLUSIONS: ICH was present in 75% of the EVT population, but PH or sICH were infrequent. The presence of any ICH did not worsen functional outcomes or modify EVT treatment effect at 90-day follow-up. The high rate of hemorrhages overall still represents an opportunity for adjunctive therapies in EVT patients with a large ischemic core.

Endovascular thrombectomy plus medical care versus medical care alone for large ischaemic stroke: 1-year outcomes of the SELECT2 trial.

BACKGROUND: Multiple randomised trials have shown efficacy and safety of endovascular thrombectomy in patients with large ischaemic stroke. The aim of this study was to evaluate long-term (ie, at 1 year) evidence of benefit of thrombectomy for these patients. METHODS: SELECT2 was a phase 3, open-label, international, randomised controlled trial with blinded endpoint assessment, conducted at 31 hospitals in the USA, Canada, Spain, Switzerland, Australia, and New Zealand. Patients aged 18-85 years with ischaemic stroke due to proximal occlusion of the internal carotid artery or of the first segment of the middle cerebral artery, showing large ischaemic core on non-contrast CT (Alberta Stroke Program Early Computed Tomographic Score of 3-5 [range 0-10, with lower values indicating larger infarctions]) or measuring 50 mL or more on CT perfusion and MRI, were randomly assigned, within 24 h of ischaemic stroke onset, to thrombectomy plus medical care or to medical care alone. The primary outcome for this analysis was the ordinal modified Rankin Scale (range 0-6, with higher scores indicating greater disability) at 1-year follow-up in an intention-to-treat population. The trial is registered at ClinicalTrials.gov (NCT03876457) and is completed. FINDINGS: The trial was terminated early for efficacy at the 90-day follow-up after 352 patients had been randomly assigned (178 to thrombectomy and 174 to medical care only) between Oct 11, 2019, and Sept 9, 2022. Thrombectomy significantly improved the 1-year modified Rankin Scale score distribution versus medical care alone (Wilcoxon-Mann-Whitney probability of superiority 0·59 [95% CI 0·53-0·64]; p=0·0019; generalised odds ratio 1·43 [95% CI 1·14-1·78]). At the 1-year follow-up, 77 (45%) of 170 patients receiving thrombectomy had died, compared with 83 (52%) of 159 patients receiving medical care only (1-year mortality relative risk 0·89 [95% CI 0·71-1·11]). INTERPRETATION: In patients with ischaemic stroke due to a proximal occlusion and large core, thrombectomy plus medical care provided a significant functional outcome benefit compared with medical care alone at 1-year follow-up. FUNDING: Stryker Neurovascular.

Endovascular Thrombectomy for Large Ischemic Stroke Across Ischemic Injury and Penumbra Profiles.

Importance: Whether endovascular thrombectomy (EVT) efficacy for patients with acute ischemic stroke and large cores varies depending on the extent of ischemic injury is uncertain. Objective: To describe the relationship between imaging estimates of irreversibly injured brain (core) and at-risk regions (mismatch) and clinical outcomes and EVT treatment effect. Design, Setting, and Participants: An exploratory analysis of the SELECT2 trial, which randomized 352 adults (18-85 years) with acute ischemic stroke due to occlusion of the internal carotid or middle cerebral artery (M1 segment) and large ischemic core to EVT vs medical management (MM), across 31 global centers between October 2019 and September 2022. Intervention: EVT vs MM. Main Outcomes and Measures: Primary outcome was functional outcome-90-day mRS score (0, no symptoms, to 6, death) assessed by adjusted generalized OR (aGenOR; values >1 represent more favorable outcomes). Benefit of EVT vs MM was assessed across levels of ischemic injury defined by noncontrast CT using ASPECTS score and by the volume of brain with severely reduced blood flow on CT perfusion or restricted diffusion on MRI. Results: Among 352 patients randomized, 336 were analyzed (median age, 67 years; 139 [41.4%] female); of these, 168 (50%) were randomized to EVT, and 2 additional crossover MM patients received EVT. In an ordinal analysis of mRS at 90 days, EVT improved functional outcomes compared with MM within ASPECTS categories of 3 (aGenOR, 1.71 [95% CI, 1.04-2.81]), 4 (aGenOR, 2.01 [95% CI, 1.19-3.40]), and 5 (aGenOR, 1.85 [95% CI, 1.22-2.79]). Across strata for CT perfusion/MRI ischemic core volumes, aGenOR for EVT vs MM was 1.63 (95% CI, 1.23-2.16) for volumes ≥70 mL, 1.41 (95% CI, 0.99-2.02) for ≥100 mL, and 1.47 (95% CI, 0.84-2.56) for ≥150 mL. In the EVT group, outcomes worsened as ASPECTS decreased (aGenOR, 0.91 [95% CI, 0.82-1.00] per 1-point decrease) and as CT perfusion/MRI ischemic core volume increased (aGenOR, 0.92 [95% CI, 0.89-0.95] per 10-mL increase). No heterogeneity of EVT treatment effect was observed with or without mismatch, although few patients without mismatch were enrolled. Conclusion and Relevance: In this exploratory analysis of a randomized clinical trial of patients with extensive ischemic stroke, EVT improved clinical outcomes across a wide spectrum of infarct volumes, although enrollment of patients with minimal penumbra volume was low. In EVT-treated patients, clinical outcomes worsened as presenting ischemic injury estimates increased. Trial Registration: ClinicalTrials.gov Identifier: NCT03876457.

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.

Large vessel occlusion prediction scale thresholds that are sensitive for DAWN Trial patients.

BACKGROUND: Large vessel occlusion (LVO) prediction scales are used to triage prehospital suspected stroke patients with a high probability of LVO stroke to endovascular therapy centers. The sensitivities of these scales in the 6-to-24-h time window are unknown. Higher scale score thresholds are typically less sensitive and more specific. Knowing the highest scale score thresholds that remain sensitive could inform threshold selection for clinical use. Sensitivities may also vary between left and right-sided LVOs. METHODS: LVO prediction scale scores were retrospectively calculated using the National Institutes of Health Stroke Scale (NIHSS) scores of patients enrolled in the DAWN Trial. All patients had last known well times between 6 and 24 h, NIHSS scores ≥ 10, intracranial internal carotid artery or proximal middle cerebral artery occlusions, and mismatches between their clinical severities and infarct core volumes. Scale thresholds with sensitivities ≥ 85% were identified, along with scores ≥ 5% more sensitive for left or right-sided LVOs. Specificities could not be calculated because all patients had LVOs. RESULTS: A total of 201 out of 206 patients had the required NIHSS subitem scores. CPSS = 3, C-STAT ≥ 2, FAST-ED ≥ 4, G-FAST ≥ 3, RACE ≥ 5, and SAVE ≥ 3 were the highest thresholds that were still 85% sensitive for DAWN Trial LVO stroke patients. RACE ≥ 5 was the only typically used score threshold more sensitive for right-sided LVOs, though similar small differences were seen for other scales at higher thresholds. CONCLUSIONS: Our findings likely represent the maximum sensitivities of the LVO prediction scales tested for ideal thrombectomy candidates in the 6-to-24-h time window because NIHSS scores were documented in hospitals during a clinical trial rather than in the prehospital setting. Patients with NIHSS scores < 10 or more distal LVOs would lower sensitivities further. Selecting even higher scale thresholds for LVO triage would lead to many missed LVO strokes.

Trial of Endovascular Thrombectomy for Large Ischemic Strokes.

BACKGROUND: Trials of the efficacy and safety of endovascular thrombectomy in patients with large ischemic strokes have been carried out in limited populations. METHODS: We performed a prospective, randomized, open-label, adaptive, international trial involving patients with stroke due to occlusion of the internal carotid artery or the first segment of the middle cerebral artery to assess endovascular thrombectomy within 24 hours after onset. Patients had a large ischemic-core volume, defined as an Alberta Stroke Program Early Computed Tomography Score of 3 to 5 (range, 0 to 10, with lower scores indicating larger infarction) or a core volume of at least 50 ml on computed tomography perfusion or diffusion-weighted magnetic resonance imaging. Patients were assigned in a 1:1 ratio to endovascular thrombectomy plus medical care or to medical care alone. The primary outcome was the modified Rankin scale score at 90 days (range, 0 to 6, with higher scores indicating greater disability). Functional independence was a secondary outcome. RESULTS: The trial was stopped early for efficacy; 178 patients had been assigned to the thrombectomy group and 174 to the medical-care group. The generalized odds ratio for a shift in the distribution of modified Rankin scale scores toward better outcomes in favor of thrombectomy was 1.51 (95% confidence interval [CI], 1.20 to 1.89; P<0.001). A total of 20% of the patients in the thrombectomy group and 7% in the medical-care group had functional independence (relative risk, 2.97; 95% CI, 1.60 to 5.51). Mortality was similar in the two groups. In the thrombectomy group, arterial access-site complications occurred in 5 patients, dissection in 10, cerebral-vessel perforation in 7, and transient vasospasm in 11. Symptomatic intracranial hemorrhage occurred in 1 patient in the thrombectomy group and in 2 in the medical-care group. CONCLUSIONS: Among patients with large ischemic strokes, endovascular thrombectomy resulted in better functional outcomes than medical care but was associated with vascular complications. Cerebral hemorrhages were infrequent in both groups. (Funded by Stryker Neurovascular; SELECT2 ClinicalTrials.gov number, NCT03876457.).

Mediation of Successful Reperfusion Effect through Infarct Growth and Cerebral Edema: A Pooled, Patient-Level Analysis of EXTEND-IA Trials and SELECT Prospective Cohort.

OBJECTIVE: Reperfusion therapy is highly beneficial for ischemic stroke. Reduction in both infarct growth and edema are plausible mediators of clinical benefit with reperfusion. We aimed to quantify these mediators and their interrelationship. METHODS: In a pooled, patient-level analysis of the EXTEND-IA trials and SELECT study, we used a mediation analysis framework to quantify infarct growth and cerebral edema (midline shift) mediation effect on successful reperfusion (modified Treatment in Cerebral Ischemia ≥ 2b) association with functional outcome (modified Rankin Scale distribution). Furthermore, we evaluated an additional pathway to the original hypothesis, where infarct growth mediated successful reperfusion effect on midline shift. RESULTS: A total 542 of 665 (81.5%) eligible patients achieved successful reperfusion. Baseline clinical and imaging characteristics were largely similar between those achieving successful versus unsuccessful reperfusion. Median infarct growth was 12.3ml (interquartile range [IQR] = 1.8-48.4), and median midline shift was 0mm (IQR = 0-2.2). Of 249 (37%) demonstrating a midline shift of ≥1mm, median shift was 2.75mm (IQR = 1.89-4.21). Successful reperfusion was associated with reductions in both predefined mediators, infarct growth (ß = -1.19, 95% confidence interval [CI] = -1.51 to -0.88, p < 0.001) and midline shift (adjusted odds ratio = 0.36, 95% CI = 0.23-0.57, p < 0.001). Successful reperfusion association with improved functional outcome (adjusted common odds ratio [acOR] = 2.68, 95% CI = 1.86-3.88, p < 0.001) became insignificant (acOR = 1.39, 95% CI = 0.95-2.04, p = 0.094) when infarct growth and midline shift were added to the regression model. Infarct growth and midline shift explained 45% and 34% of successful reperfusion effect, respectively. Analysis considering an alternative hypothesis demonstrated consistent results. INTERPRETATION: In this mediation analysis from a pooled, patient-level cohort, a significant proportion (~80%) of successful reperfusion effect on functional outcome was mediated through reduction in infarct growth and cerebral edema. Further studies are required to confirm our findings, detect additional mediators to explain successful reperfusion residual effect, and identify novel therapeutic targets to further enhance reperfusion benefits. ANN NEUROL 2023;93:793-804.

Thrombectomy Outcomes With General vs Nongeneral Anesthesia: A Pooled Patient-Level Analysis From the EXTEND-IA Trials and SELECT Study.

BACKGROUND AND OBJECTIVES: The effect of anesthesia choice on endovascular thrombectomy (EVT) outcomes is unclear. Collateral status on perfusion imaging may help identify the optimal anesthesia choice. METHODS: In a pooled patient-level analysis of EXTEND-IA, EXTEND-IA TNK, EXTEND-IA TNK part II, and SELECT, EVT functional outcomes (modified Rankin Scale score distribution) were compared between general anesthesia (GA) vs non-GA in a propensity-matched sample. Furthermore, we evaluated the association of collateral flow on perfusion imaging, assessed by hypoperfusion intensity ratio (HIR) - Tmax > 10 seconds/Tmax > 6 seconds (good collaterals - HIR < 0.4, poor collaterals - HIR ≥ 0.4) on the association between anesthesia type and EVT outcomes. RESULTS: Of 725 treated with EVT, 299 (41%) received GA and 426 (59%) non-GA. The baseline characteristics differed in presentation National Institutes of Health Stroke Scale score (median [interquartile range] GA: 18 [13-22], non-GA: 16 [11-20], p < 0.001) and ischemic core volume (GA: 15.0 mL [3.2-38.0] vs non-GA: 9.0 mL [0.0-31.0], p < 0.001). In addition, GA was associated with longer last known well to arterial access (203 minutes [157-267] vs 186 minutes [138-252], p = 0.002), but similar procedural time (35.5 minutes [23-59] vs 34 minutes [22-54], p = 0.51). Of 182 matched pairs using propensity scores, baseline characteristics were similar. In the propensity score-matched pairs, GA was independently associated with worse functional outcomes (adjusted common odds ratio [adj. cOR]: 0.64, 95% CI: 0.44-0.93, p = 0.021) and higher neurologic worsening (GA: 14.9% vs non-GA: 8.9%, aOR: 2.10, 95% CI: 1.02-4.33, p = 0.045). Patients with poor collaterals had worse functional outcomes with GA (adj. cOR: 0.47, 95% CI: 0.29-0.76, p = 0.002), whereas no difference was observed in those with good collaterals (adj. cOR: 0.93, 95% CI: 0.50-1.74, p = 0.82), p interaction: 0.07. No difference was observed in infarct growth overall and in patients with good collaterals, whereas patients with poor collaterals demonstrated larger infarct growth with GA with a significant interaction between collaterals and anesthesia type on infarct growth rate (p interaction: 0.020). DISCUSSION: GA was associated with worse functional outcomes after EVT, particularly in patients with poor collaterals in a propensity score-matched analysis from a pooled patient-level cohort from 3 randomized trials and 1 prospective cohort study. The confounding by indication may persist despite the doubly robust nature of the analysis. These findings have implications for randomized trials of GA vs non-GA and may be of utility for clinicians when making anesthesia type choice. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that use of GA is associated with worse functional outcome in patients undergoing EVT. TRIAL REGISTRATION INFORMATION: EXTEND-IA: ClinicalTrials.gov (NCT01492725); EXTEND-IA TNK: ClinicalTrials.gov (NCT02388061); EXTEND-IA TNK part II: ClinicalTrials.gov (NCT03340493); and SELECT: ClinicalTrials.gov (NCT02446587).

Delayed Functional Independence After Neurothrombectomy (DEFIANT) score: analysis of the Trevo Retriever Registry.

BACKGROUND: Chronological heterogeneity in neurological improvement after endovascular thrombectomy (EVT) for large vessel occlusion (LVO) stroke is commonly observed in clinical practice. Understanding the temporal progression of functional independence after EVT, especially delayed functional independence in patients who do not improve early, is essential for prognostication and rehabilitation. We aim to determine the incidence of early functional independence (EFI) and delayed functional independence (DFI), identify associated predictors after EVT, and develop the Delayed Functional Independence After Neurothrombectomy (DEFIANT) score. METHODS: Demographic, clinical, radiological, treatment, and procedural information were analyzed from the Trevo Registry (patients undergoing EVT due to anterior LVO using the Trevo stent retriever). Incidence and predictors of EFI (modified Rankin Scale (mRS) score 0-2 at discharge) and DFI (mRS score 0-2 at 90 days in non-EFI patients) were analyzed. RESULTS: A total of 1623 patients met study criteria. EFI was observed in 45% (730) of patients. Among surviving non-EFI patients (884), DFI was observed in 35% (308). Younger age (p=0.003), lower discharge National Institutes of Health Stroke Scale (NIHSS) score (p<0.0001), and absence of any hemorrhage (p=0.021) were independent predictors of DFI. After age 60, the probability of DFI declines significantly with 5 year age increments (approximately 7% decline for every 5 years; p(DFI)= 1.3559-0.0699, p for slope=0.001). The DEFIANT score is available online (https://bit.ly/3KZRVq5). CONCLUSION: Approximately 45% of patients experience EFI. About one-third of non-early improvers experience DFI. Younger age, lower discharge NIHSS score, and absence of any hemorrhage were independent predictors of DFI among non-early improvers.

Clinical effectiveness of endovascular stroke treatment in the early and extended time windows.

BACKGROUND: The clinical efficacy of mechanical thrombectomy has been unequivocally demonstrated in multiple randomized clinical trials. However, these studies were performed in carefully selected centers and utilized strict inclusion criteria. AIM: We aimed to assess the clinical effectiveness of mechanical thrombectomy in a prospective registry. METHODS: A total of 2008 patients from 76 sites across 12 countries were enrolled in a prospective open-label mechanical thrombectomy registry. Patients were categorized into the corresponding cohorts of the SWIFT-Prime, DAWN, and DEFUSE 3 trials according to the basic demographic and clinical criteria without considering specific parenchymal imaging findings. Baseline and outcome variables were compared across the corresponding groups. RESULTS: As compared to the treated patients in the actual trials, registry-derived patients tended to be younger and had lower baseline ASPECTS. In addition, time to treatment was earlier and the use of intravenous tissue plasminogen activator (IV-tPA) and general anesthesia were higher in DAWN- and DEFUSE-3 registry derived patients versus their corresponding trials. Reperfusion rates were higher in the registry patients. The rates of 90-day good outcome (mRS0-2) in registry-derived patients were comparable to those of the patients treated in the corresponding randomized clinical trials (SWIFT-Prime, 64.5% vs. 60.2%; DAWN, 50.4% vs. 48.6%; Beyond-DAWN: 52.4% vs. 48.6%; DEFUSE 3, 52% vs. 44.6%, respectively; all P > 0.05). Registry-derived patients had significant less disability than the corresponding randomized clinical trial controls (ordinal modified Rankin Scale (mRS) shift odds ratio (OR), P < 0.05 for all). CONCLUSION: Our study provides favorable generalizability data for the safety and efficacy of thrombectomy in the "real-world" setting and supports that patients may be safely treated outside the constraints of randomized clinical trials.

Collateral Circulation in Thrombectomy for Stroke After 6 to 24 Hours in the DAWN Trial.

BACKGROUND AND PURPOSE: Collaterals govern the pace and severity of cerebral ischemia, distinguishing fast or slow progressors and corresponding therapeutic opportunities. The fate of sustained collateral perfusion or collateral failure is poorly characterized. We evaluated the nature and impact of collaterals on outcomes in the late time window DAWN trial (Diffusion-Weighted Imaging or Computed Tomography Perfusion Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention With Trevo). METHODS: The DAWN Imaging Core Lab prospectively scored collateral grade on baseline computed tomography angiography (CTA; endovascular and control arms) and digital subtraction angiography (DSA; endovascular arm only), blinded to all other data. CTA collaterals were graded with the Tan scale and DSA collaterals were scored by ASITN grade (American Society of Interventional and Therapeutic Neuroradiology collateral score). Descriptive statistics characterized CTA collateral grade in all DAWN subjects and DSA collaterals in the endovascular arm. The relationship between collateral grade and day 90 outcomes were separately analyzed for each treatment arm. RESULTS: Collateral circulation to the ischemic territory was evaluated on CTA (n=144; median 2, 0-3) and DSA (n=57; median 2, 1-4) before thrombectomy in 161 DAWN subjects (mean age 69.8±13.6 years; 55.3% women; 91 endovascular therapy, 70 control). CTA revealed a broad range of collaterals (Tan grade 3, n=64 [44%]; 2, n=45 [31%]; 1, n=31 [22%]; 0, n=4 [3%]). DSA also showed a diverse range of collateral grades (ASITN grade 4, n=4; 3, n=22; 2, n=27; 1, n=4). Across treatment arms, baseline demographics, clinical variables except atrial fibrillation (41.6% endovascular versus 25.0% controls, P=0.04), and CTA collateral grades were balanced. Differences were seen across the 3 levels of collateral flow (good, fair, poor) for baseline National Institutes of Health Stroke Scale, blood glucose <150, diabetes, previous ischemic stroke, baseline and 24-hour core infarct volume, baseline and 24-hour Alberta Stroke Program Early CT Score, dramatic infarct progression, final Thrombolysis in Cerebral Infarction 2b+, and death. Collateral flow was a significant predictor of 90-day modified Rankin Scale score of 0 to 2 in the endovascular arm, with 43.7% (31/71) of subjects with good collaterals, 30.8% (16/52) of subjects with fair collaterals, and 17.7% (6/34) of subjects with poor collaterals reaching modified Rankin Scale score of 0 to 2 at 90 days (P=0.026). CONCLUSIONS: DAWN subjects enrolled at 6 to 24 hours after onset with limited infarct cores had a wide range of collateral grades on both CTA and DSA. Even in this late time window, better collaterals lead to slower stroke progression and better functional outcomes. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02142283.

Influence of time to endovascular stroke treatment on outcomes in the early versus extended window paradigms.

BACKGROUND: The effect of time from stroke onset to thrombectomy in the extended time window remains poorly characterized. AIM: We aimed to analyze the relationship between time to treatment and clinical outcomes in the early versus extended time windows. METHODS: Proximal anterior circulation occlusion patients from a multicentric prospective registry were categorized into early (≤6 h) or extended (>6-24 h) treatment window. Patients with baseline National Institutes of Health Stroke Scale (NIHSS) ≥ 10 and intracranial internal carotid artery or middle cerebral artery-M1-segment occlusion and pre-morbid modified Rankin scale (mRS) 0-1 ("DAWN-like" cohort) served as the population for the primary analysis. The relationship between time to treatment and 90-day mRS, analyzed in ordinal (mRS shift) and dichotomized (good outcome, mRS 0-2) fashion, was compared within and across the extended and early windows. RESULTS: A total of 1603 out of 2008 patients qualified. Despite longer time to treatment (9[7-13.9] vs. 3.4[2.5-4.3] h, p < 0.001), extended-window patients (n = 257) had similar rates of symptomatic intracranial hemorrhage (sICH; 0.8% vs. 1.7%, p = 0.293) and 90-day-mortality (10.5% vs. 9.6%, p = 0.714) with only slightly lower rates of 90-day good outcomes (50.4% vs. 57.6%, p = 0.047) versus early-window patients (n = 709). Time to treatment was associated with 90-day disability in both ordinal (adjusted odd ratio (aOR), ≥ 1-point mRS shift: 0.75; 95%CI [0.66-0.86], p < 0.001) and dichotomized (aOR, mRS 0-2: 0.73; 95%CI [0.62-0.86], p < 0.001) analyses in the early- but not in the extended-window (aOR, mRS shift: 0.96; 95%CI [0.90-1.02], p = 0.15; aOR, mRS0-2: 0.97; 95%CI [0.90-1.04], p = 0.41). Early-window patients had significantly lower 90-day functional disability (aOR, mRS shift: 1.533; 95%CI [1.138-2.065], p = 0.005) and a trend towards higher rates of good outcomes (aOR, mRS 0-2: 1.391; 95%CI [0.972-1.990], p = 0.071). CONCLUSIONS: The impact of time to thrombectomy on outcomes appears to be time dependent with a steep influence in the early followed by a less significant plateau in the extended window. However, every effort should be made to shorten treatment times regardless of ischemia duration.

POSITIVE: Perfusion imaging selection of ischemic stroke patients for endovascular therapy.

BACKGROUND: The PerfusiOn imaging Selection of Ischemic sTroke patIents for endoVascular thErapy (POSITIVE) trial was designed to evaluate functional outcome in patients with emergent large vessel occlusion (ELVO) presenting within 0-12 hours with pre-specified bifurcated arms of early and late window presentation, who were selected for endovascular thrombectomy with non-vendor specific commercially available perfusion imaging software. Recent trials demonstrating the benefit of thrombectomy up to 16-24 hours following ELVO removed equipoise to randomize late window ELVO patients and therefore the trial was halted. METHODS: Up to 200 patients were to be enrolled in this FDA-cleared, prospective, randomized, multicenter international trial to compare thrombectomy and best medical management in patients with ELVO ineligible for or refractory to treatment with IV tissue plasminogen activator (IV-tPA) selected with perfusion imaging and presenting within 0-12 hours of last seen normal. The primary outcome was 90-day clinical outcome as measured by the raw modified Rankin Scale (mRS) with scores 5 and 6 collapsed (mRS shift analysis). RESULTS: The POSITIVE trial suspended enrollment with the release of results from the DAWN trial and was stopped after the release of the DEFUSE 3 trial results. Thirty-three patients were enrolled (21 for medical management and 12 for thrombectomy). Twelve of the 33 patients were enrolled in the 6-12 hour cohort. Despite the early cessation, the primary outcome demonstrated statistically significant superior clinical outcomes for patients treated with thrombectomy (P=0.0060). The overall proportion of patients achieving an mRS score of 0-2 was 75% in the thrombectomy cohort and 43% in the medical management cohort (OR 4.00, 95% CI 0.84 to 19.2). CONCLUSION: POSITIVE supports the already established practice of delayed thrombectomy for appropriately selected patients presenting within 0-12 hours selected by perfusion imaging from any vendor. The results of the POSITIVE trial are consistent with other thrombectomy trials. The statistically significant effect on functional improvement, despite the small number of patients, reinforces the robust benefits of thrombectomy. CLINICAL TRIAL REGISTRATION: NCT01852201.

Serial ASPECTS in the DAWN Trial: Infarct Evolution and Clinical Impact.

Background and Purpose: The impact of baseline ischemia on Alberta Stroke Program Early CT Score (ASPECTS) and evolution over 24 hours may be distinct in late thrombectomy. We analyzed predictors of serial ASPECTS and clinical outcomes in the DAWN trial (Diffusion-Weighted Imaging or CTP Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention With Trevo). Methods: The DAWN Imaging Core Laboratory independently scored ASPECTS at baseline and 24 hours. Descriptive statistics characterized ASPECTS on computed tomography/magnetic resonance imaging at baseline and 24 hours, delineating ASPECTS change over 24 hours. Results: 206 subjects (mean age 70.0±13.7 years; 54.9% (n=113) female; baseline National Institutes of Health Stroke Scale median (interquartile range) 17 (13, 21) were included. Baseline ASPECTS was median (interquartile range) 8.0 (7­8), with 92/205 (44.9%) between 0 and 7 and 113/205 (55.1%) 8 and 10. 24-hour ASPECTS was median 6.0 (4­8), with ASPECTS change or infarct evolution having median −1, ranging from −8 to +2. Multivariable logistic regression showed older age (odds ratio [OR] for 10-year interval, 1.26 [95% CI, 1.02­1.55], P=0.030) and dyslipidemia (OR, 1.84 [95% CI, 1.06­3.19], P=0.031) were independently associated with higher baseline ASPECTS. Higher 24-hour ASPECTS was predicted by endovascular treatment (OR, 2.76 [95% CI, 1.58­4.81], P=0.0004), baseline glucose <150 mg/dL (OR, 2.86 [95% CI, 1.50­5.46], P=0.001), lower baseline National Institutes of Health Stroke Scale (OR, 0.93 [95% CI, 0.89­0.98], P=0.010), and older age (OR for 10-year interval, 1.25 [95% CI, 1.01­1.55], P=0.041). Internal carotid artery lesion location (OR, 0.47 [95% CI, 0.24­0.89], P=0.021) was inversely related to 24-hour ASPECTS. Good clinical outcome (day 90 modified Rankin Scale score 0­2) was predicted by 24-hour ASPECTS (OR, 1.46 [95% CI, 1.08­1.96], P=0.014). Extensive infarct evolution (ASPECTS decrease ≥6) occurred in 14/201 (7.0%). Elevated baseline serum glucose ≥150 mg/dL was a predictor of ASPECTS decrease of ≥4 points (OR, 2.78 [95% CI, 1.21­6.35] P=0.016) as was internal carotid artery occlusion (OR, 2.49 [95% CI, 1.05­5.88]; P=0.038). ASPECTS change was influenced by treatment arm (P=0.001 by Wilcoxon), including 0 ASPECTS change in 42/105 (40.0%) of the endovascular arm and only 20/96 (20.8%) of the medical arm. Conclusions: DAWN subjects enrolled with small infarct cores had a broad range of baseline ASPECTS. Twenty-four-hour ASPECTS, strikingly influenced by endovascular therapy, predicted good clinical outcomes. Registration: https://www.clinicaltrials.gov; Unique identifier: NCT02142283.

New Class of Radially Adjustable Stentrievers for Acute Ischemic Stroke: Primary Results of the Multicenter TIGER Trial.

[Figure: see text].

First pass effect in patients with large vessel occlusion strokes undergoing neurothrombectomy: insights from the Trevo Retriever Registry.

BACKGROUND: First pass effect (FPE), defined as near-total/total reperfusion of the territory (modified Thrombolysis in Cerebral Infarction (mTICI) 2c/3) of the occluded artery after a single thrombectomy attempt (single pass), has been associated with superior safety and efficacy outcomes than in patients not experiencing FPE. OBJECTIVE: To characterize the clinical features, incidence, and predictors of FPE in the anterior and posterior circulation among patients enrolled in the Trevo Registry. METHODS: Data were analyzed from the Trevo Retriever Registry. Univariate and multivariable analyses were used to assess the relationship of patient (demographics, clinical, occlusion location, collateral grade, Alberta Stroke Program Early CT Score (ASPECTS)) and device/technique characteristics with FPE (mTICI 2c/3 after single pass). RESULTS: FPE was achieved in 27.8% (378/1358) of patients undergoing anterior large vessel occlusion (LVO) thrombectomy. Multivariable regression analysis identified American Society of Interventional and Therapeutic Neuroradiology (ASITN) levels 2-4, higher ASPECTS, and presence of atrial fibrillation as independent predictors of FPE in anterior LVO thrombectomy. Rates of modified Rankin Scale (mRS) score 0-2 at 90 days were higher (63.9% vs 53.5%, p<0.0006), and 90-day mortality (11.4% vs 12.8%, p=0.49) was comparable in the FPE group and non-FPE group. Rate of FPE was 23.8% (19/80) among basilar artery occlusion strokes, and outcomes were similar between FPE and non-FPE groups (mRS score 0-2, 47.4% vs 52.5%, p=0.70; mortality 26.3% vs 18.0%, p=0.43). Notably, there were no difference in outcomes in FPE versus non-FPE mTICI 2c/3 patients. CONCLUSION: Twenty-eight percent of patients undergoing anterior LVO thrombectomy and 24% of patients undergoing basilar artery occlusion thrombectomy experience FPE. Independent predictors of FPE in anterior circulation LVO thrombectomy include higher ASITN levels, higher ASPECTS, and the presence of atrial fibrillation.

Endovascular therapy in the distal neurovascular territory: results of a large prospective registry.

BACKGROUND: There is a paucity of data regarding mechanical thrombectomy (MT) in distal arterial occlusions (DAO). We aim to evaluate the safety and efficacy of MT in patients with DAO and compare their outcomes with proximal arterial occlusion (PAO) strokes. METHODS: The Trevo Registry was a prospective open-label MT registry including 2008 patients from 76 sites across 12 countries. Patients were categorized into: PAO: intracranial ICA, and MCA-M1; and DAO: MCA-M2, MCA-M3, ACA, and PCA. Baseline and outcome variables were compared across the PAO vs DAO patients with pre-morbid mRS 0-2. RESULTS: Among 407 DAOs including 350 (86.0%) M2, 25 (6.1%) M3, 10 (2.5%) ACA, and 22 (5.4%) PCA occlusions, there were 376 DAO with pre-morbid mRS 0-2 which were compared with 1268 PAO patients. The median baseline NIHSS score was lower in DAO (13 [8-18] vs 16 [12-20], P<0.001). There were no differences in terms of age, sex, IV-tPA use, co-morbidities, or time to treatment across DAO vs PAO. The rates of post-procedure reperfusion, symptomatic intracranial hemorrhage (sICH), and 90-mortality were comparable between both groups. DAO showed significantly higher rates of 90-day mRS 0-2 (68.3% vs 56.5%, P<0.001). After adjustment for potential confounders, the level of arterial occlusion was not associated with the chances of excellent outcome (DAO for 90-day mRS 0-1: OR; 1.18, 95% CI [0.90 to 1.54], P=0.225), successful reperfusion or SICH. However, DAO patients were more likely to be functionally independent (mRS 0-2: OR; 1.45, 95% CI [1,09 to 1.92], P=0.01) or dead (OR; 1.54, 95% CI [1.06 to 2.27], P=0.02) at 90 days. CONCLUSION: Endovascular therapy in DAO appears to result in a comparable safety and technical success profile as in PAO. The potential benefits of DAO thrombectomy should be investigated in future randomized trials.

Endovascular thrombectomy in patients with large core ischemic stroke: a cost-effectiveness analysis from the SELECT study.

BACKGROUND: It is unknown whether endovascular thrombectomy (EVT) is cost effective in large ischemic core infarcts. METHODS: In the prospective, multicenter, cohort study of imaging selection study (SELECT), large core was defined as computed tomography (CT) ASPECTS<6 or computed tomography perfusion (CTP) ischemic core volume (rCBF<30%) ≥50 cc. A Markov model estimated costs, quality-adjusted life years (QALYs) and the incremental cost-effectiveness ratio (ICER) of EVT compared with medical management (MM) over lifetime. The willingness to pay (WTP) per QALY was set at $50 000 and $100 000 and the net monetary benefits (NMB) were calculated. Probabilistic sensitivity analysis (PSA) and cost-effectiveness acceptability curves (CEAC) for EVT were assessed in SELECT and other pivotal trials. RESULTS: From 361 patients enrolled in SELECT, 105 had large core on CT or CTP (EVT 62, MM 43). 19 (31%) EVT vs 6 (14%) MM patients achieved modified Rankin Scale (mRS) score 0-2 (OR 3.27, 95% CI 1.11 to 9.62, P=0.03) with a shift towards better mRS (cOR 2.12, 95% CI 1.05 to 4.31, P=0.04). Over the projected lifetime of patients presenting with large core, EVT led to incremental costs of $33 094 and a gain of 1.34 QALYs per patient, resulting in ICER of $24 665 per QALY. EVT has a higher NMB compared with MM at lower (EVT -$42 747, MM -$76 740) and upper (EVT $155 041, MM $57 134) WTP thresholds. PSA confirmed the results and CEAC showed 77% and 92% acceptability of EVT at the WTP of $50 000 and $100 000, respectively. EVT was associated with an increment of $29 225 in societal costs. The pivotal EVT trials (HERMES, DAWN, DEFUSE 3) were dominant in a sensitivity analysis at the same inputs, with societal cost-savings of $37 901, $86 164 and $22 501 and a gain of 1.62, 2.36 and 2.21 QALYs, respectively. CONCLUSIONS: In a non-randomized prospective cohort study, EVT resulted in better outcomes in large core patients with higher QALYs, NMB and high cost-effectiveness acceptability rates at current WTP thresholds. Randomized trials are needed to confirm these results. CLINICAL TRIAL REGISTRATION: NCT02446587.

Impact of Periprocedural and Technical Factors and Patient Characteristics on Revascularization and Outcome in the DAWN Trial.

Background and Purpose- Because of unique attributes of mechanical thrombectomy performed between 6 and 24 hours after symptom onset in acute ischemic stroke patients, it is not known if predictors of angiographic recanalization and favorable outcome in patients treated with thrombectomy in the late (6-24 hour) time window are similar to those treated in the early time window. Methods- We analyzed data from the DAWN trial (DWI or CTP Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention With Trevo) which enrolled patients with symptom onset 6 to 24hours after last known well and occlusion of the intracranial internal carotid artery or proximal middle cerebral artery with a mismatch between severity of clinical deficit and infarct core volume as identified by computed tomography-perfusion or diffusion magnetic resonance imaging. We evaluated the effect of tandem occlusions, periprocedural heparin use, procedural speed (from puncture to procedure completion), general anesthesia, balloon-guide catheters, thrombectomy device size, and number of passes on substantial reperfusion (modified Thrombolysis in Cerebral Infarction 2b/3) and on likelihood of obtaining a modified Rankin Scale at 3 months indicating functional independence. Results- Of 107 patients who underwent MT in the interventional arm of DAWN, substantial reperfusion and modified Rankin Scale score 0 to 2 at 3 months was seen in 90 (84%) and 52 (49%), respectively. In univariate analysis, general anesthesia (odds ratio [OR] 0.27; P=0.042) and ≥3 passes with stent retriever (OR, 0.17; P=0.002) were inversely associated with substantial reperfusion. In multivariate analyses, only ≥3 passes were associated with lack of revascularization (OR, 0.17; P=0.002). in univariate analysis ≥3 passes (OR, 0.24; P =0.003) and baseline National Institutes of Health Stroke Scale score >17 (OR, 0.19; P<0.001) were inversely associated with functional independence at 3 months. In multivariate analyses, ≥3 passes (OR, 0.24; P=0.003) and National Institutes of Health Stroke Scale score >17 (OR, 0.19; P<0.001) remained inversely associated with favorable outcome at 3 months. Conclusions- Patients requiring ≥3 thrombectomy passes had reduced substantial reperfusion and favorable outcome at 3 months in DAWN. Whether or not additional thrombectomy techniques beyond ≥3 thrombectomy passes with the Trevo stent retriever are beneficial for patient outcomes in this patient population remains to be clarified by future studies. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT02142283.