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Importance:Clinical trials focusing on new mechanical thrombectomy (MT) technologies have been typically single-arm studies using historical comparison data to determine the safety and efficacy of the novel device. To date, there has not been a contemporaneous prospective, randomized, controlled study comparing standard to newer designed stent-retrievers.Objective:To evaluate the safety and efficacy of the pRESET (phenox Ltd) compared to the Solitaire (Medtronic Corp) thrombectomy devices in the treatment of large vessel occlusion strokes (LVOS).Methods:Multicenter, prospective, randomized, open-label, blinded endpoint, core lab adjudicated, non-inferiority trial that enrolled 340 patients from October 2019 to February 2022 across 19 US & 5 German sites. Patients aged ≥ 18 years with either anterior or posterior circulation LVOS were included up to 8 hours after symptom onset. Patients were randomly assigned in a 1:1 ratio to either pRESET or Solitaire for the first three device passes.The Primary Endpoint was the proportion of patients achieving a modified Rankin Scale score of 0-2, analyzed by intent to treat with a non-inferiority margin of 0.125 based on the lower bound 95% Confidence Interval. The Primary Safety Endpoint was the proportion of subjects with device- or procedure-related symptomatic intracerebral hemorrhage at 24 (-8/+12) hours as per the SITS-MOST criteria. Secondary Outcome Measures included the rates of (1) Successful Revascularization (defined as expanded Thrombolysis in Cerebrovascular Infarction [eTICI] ≥2b50 ≤3 passes of the assigned device; (2) eTICI ≥2c following the first pass of the assigned device; (3) 90-day mortality and (4) Distribution of 90-day mRS across the entire spectrum of disability (ordinal shift).Results:The study database was locked in August 2022. The analysis is ongoing and the final results will be presented at the 2023 International Stroke Conference.Conclusions and Relevance:PROST is the first randomized clinical trial aiming to compare a novel versus an established stent-retriever technology, establishing a new scientific benchmark for stroke device trials. (ClinicalTrials.gov: NCT03994822).

Background:We sought to determine and validate a pre-reperfusion blood pressure threshold for MCA occlusions patients with better thrombectomy outcomes.Methods:We reviewed patients from 2013 to 2015 treated with thrombectomy for a MCA M1 occlusion at our center. Blood pressure measurements from available records at the time of EMS activation to the time of reperfusion were used to calculate an averaged pre-reperfusion mean arterial pressure (MAP). All patients in our analysis had successful reperfusion. Our endpoint was a mRS ≤2 at 90 days. The averaged MAP was grouped as follows: ≥85mmHg, ≥90mmHg, ≥95mmHg, ≥100mmHg, ≥110 mmHg and ≥115mmHg. We considered hourly epochs from symptom onset to reperfusion, pre-treatment ASPECTS, thrombolytics, and collateral status. Significant parameters from a univariate analysis were included into a multivariate logistic regression to determine independent predictors of outcome. The multivariate findings were then validated with a prospective set of similar patients evaluated with our mobile stroke treatment unit.Results:We reviewed 52 patients. Mean age was 70; NIHSS was 16±6; 40% (21) received t-PA; median ASPECTS score was 10; TICI 3 score was achieved in 63% (33), and 67% (35) had a good outcome. The number of patients having a mean arterial blood pressure threshold were as follows: ≥85mmHg (96%), ≥90mmHg (83%), ≥95mmHg (73%), ≥100mmHg (58%), ≥110mmHg (31%) and ≥115mmHg (15%). Reperfusion occurred as follows: ≤3hrs (4%), ≤4hrs (21%), ≤5hrs (39%), ≤6hrs (52%), ≤7hrs (67%), ≤8hrs (79%), ≤9hrs (87%), and ≤12hrs (90%). Our multivariate logistic regression model identified an average pre-reperfusion MAP ≥95mmHg as the sole factor statistically associated with a better outcome post successful thrombectomy [OR 15.1, CI 1.3-170.1,p=0.02]. Good clinical outcome in those patients with an averaged MAP ≥95mmHg was 76% and 43% in those below the threshold [OR 5.2, p=0.02]. Our validation cohort consisted of 32 patients, and a pre-reperfusion averaged MAP ≥ 95 mmHg had a sensitivity of of 93% for a good outcome.Conclusion:Our analysis suggests with validation that a pre-reperfusion averaged MAP ≥ 95mmHg results in better outcomes with successful thrombectomy and may be used as a therapeutic target in the pre-hospital setting.

Introduction:EXCELLENT (NCT03685578) is a global prospective, multicenter, real-world registry of mechanical thrombectomy for stroke with the EmboTrap device as first line treatment which includes clot collection and analysis.Aim of the study:To report the rates of clinical outcomes and clot characteristics associated with first pass reperfusion in EXCELLENT.Methods:Per pass angiographic outcomes assessed by an independent core lab were available in 984 subjects Analysis of clot from 538 cases was performed by independent central labs blinded to clinical data. 90-day mRS assessment was blinded to subject data.Results:First pass reperfusion of mTICI 2b-3 (63.2%) and 2c-3 (38.3%) was significantly predictive of mRS 0-2 or ≤pre-stroke (p=0.011 and p=0.016) but not all-cause mortality at 90 days (p=0.080 and p=0.123, respectively). Further, mTICI 2c-3 in one pass was associated with a higher rate of mRS 0-2 or ≤pre-stroke vs. mTICI 2c-3 reperfusion in >1 pass, (55.5% and 45.1%, respectively, p=0.013) and a rate of all-cause mortality at 90 days of 14.6% vs. 19.8% (p=0.097). Full patient characteristics and clinical outcomes are shown in Table 1. Notable clot composition findings included: RBC (%, mean±SD): mTICI 2c-3, 1 pass 47.69±22.25, mTICI 2c-3, >1 pass 43.86±19.05, (p=0.088); fibrin: mTICI 2c-3, 1 pass 23.20±13.80, mTICI 2c-3 >1 pass 25.40 ± 13.52 (p=0.131); von Willebrand factor (VWF): mTICI2c-3, 1 pass 16.09±14.62, mTICI 2c-3, >1 pass 19.42±17.15 (p=0.038).Conclusions:First pass reperfusion in the EXCELLENT registry was associated with better clinical outcomes at 90 days. Clots retrieved with first pass reperfusion had higher RBC and lower fibrin and VWF content compared to those who achieved reperfusion at greater than one pass.

High revascularization rates in large-vessel occlusion strokes treated by mechanical thrombectomy are not always associated with good clinical outcomes. We evaluated predictors of functional dependence despite successful revascularization among patients with acute ischemic stroke treated with thrombectomy.

Background: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 (mRS distribution) were compared between general anesthesia (GA) vs non-general anesthesia (non-GA). Further, we assessed the impact of collateral flow on perfusion imaging evaluated by hypoperfusion intensity ratio (HIR) - Tmax10 sec/Tmax6 sec) on the association between anesthesia type and EVT outcomes.Results:Of 731 treated with EVT, 305 (42%) received GA and 426 (58%) non-GA. The baseline characteristics were similar, except for presentation NIHSS (median [IQR] GA 18 [13-22], non-GA 16[11-20], p<0.001) and ischemic core volume (GA 14.1mL [3-37] vs non-GA 9mL [0-31], p=0.002). GA was associated with longer LKW to arterial access (203min [158-267] vs 186min [138-252], p=0.002), but similar procedural time (36min [23-59] vs 34min [22-54], p=0.36). Non-GA was independently associated with improved functional outcomes (adj cOR 1.42, 95%CI 1.05-1.93, p=0.024) and lower mortality (17% vs 11.3%, p=0.025). Patients with poor collaterals (HIR≥0.4) had improved functional outcomes with non-GA (adj cOR 1.53, 95%CI 1.02-2.29, p=0.038), while no difference was observed in those with good collaterals-HIR<0.4 (adj cOR 1.38, 95% CI 0.84-2.27, p=0.21).Conclusion:GA was associated with worse functional outcomes after EVT, particularly in patients with poor collaterals. These findings have implications for randomized trials of GA vs non-GA.

Endovascular mechanical thrombectomy may be used during acute ischemic stroke due to large vessel intracranial occlusion. First-generation MERCI devices achieved recanalization rates of 48% and, when coupled with intraarterial thrombolytic drugs, recanalization rates of 60% have been reported. Enhancements in embolectomy device design may improve recanalization rates.

Acute stroke from occlusion of the intracranial internal carotid artery (ICA) generally has a poor prognosis and appears to respond poorly to intravenous thrombolysis. Mechanical thrombectomy is a newly available modality for acute stroke therapy, but it is unknown whether this endovascular therapy may have a role in the specific setting of intracranial ICA occlusion. We therefore assessed the success rate of the Merci Retriever mechanical thrombectomy device in recanalization of intracranial ICA occlusions and sought to determine whether ICA recanalization with this therapy can result in better outcomes.

Introduction:Successful and fast reperfusion with endovascular thrombectomy (EVT) improves outcomes in acute ischemic strokes due to large vessel occlusion (LVO). While complete reperfusion (mTICI 3) is the ideal target, multiple passes could prolong EVT and increase complications likelihood without improving clinical outcomes. We hypothesized that pts with a single pass mTICI2b would have similar good outcomes to those with multiple passes mTICI3 with a better safety profile.Methods:From the prospective multicenter cohort study of imaging selection (SELECT), EVT pts who achieved mTICI2b and mTICI3 were stratified into those with single pass vs multiple passes. Functional independence rates at 90 day mRS and safety (sICH, neuro-worsening and mortality) were compared between pts with single pass mTICI 2b and multiple passes mTICI 3.Results:Of 361 pts enrolled, 285 received EVT, of those 70 (25%) achieved mTICI 2b and 159 (56%) mTICI 3. 89 (31%) achieved mTICI 3 with single pass, 70 (25%) with multiple passes, 33 (12%) had mTICI 2b with a single pass and 37 (13%) with multiple passes. Baseline characteristics were similar between the two groups except for larger perfusion deficit (Tmax >6s) volume in pts with multiple passes mTICI3 55 (25, 99) cc vs first pass mTICI 2b 43 (4, 79), p=0.047). Functional independence rates were higher with single pass mTICI 2b as compared to multiple passes mTICI 3 (70% vs 56%, aOR=1.51, 95% CI=0.48-4.76, p=0.78), fig 1 but did not reach statistical significance. Multiple passes mTICI 3 was associated with numerically higher mortality (13% vs 3%, p=0.16) and Neuro-worsening (13% vs 3%, p=0.16) with similar sICH: 4% vs 3%, p=1.00 rates.Conclusion:Complete reperfusion with multiple passes did not confer better outcome rates than single pass mTICI 2b and was associated with worse safety profiles. These results suggest that in the absence of complete reperfusion on first attempt, a single pass mTICI 2b may be sufficient for a successful thrombectomy.

Introduction: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 hour 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 NIHSS sub-item scores of patients enrolled in the DAWN Trial. All patients had last known well times between 6 to 24 hours, NIHSS scores ≥ 10, intracranial ICA or proximal MCA occlusions, and mismatches between their exam severities and infarct core volumes. Scale thresholds with sensitivities ≥ 85% were identified. Scores ≥ 5% more sensitive for left or right sided LVOs were identified. Specificities could not be calculated because all DAWN Trial patients had LVOs.Results:201 out of 206 patients had the required NIHSS sub-item scores. The highest score thresholds that maintained sensitivities ≥ 85% are bolded in the table.Conclusions:CPSS = 3, C-STAT ≥ 2, FAST-ED ≥ 4, G-FAST ≥ 3, RACE ≥ 5, and SAVE ≥ 3 are likely the highest thresholds that can be selected for extended window LVO triage without missing more than 15% of DAWN Trial eligible LVO strokes. For CPSS and SAVE, these are higher than the thresholds suggested by prior studies. CPSS = 3 and RACE ≥ 5 were more sensitive for right sided LVOs. These findings represent the maximum anticipated sensitivities of LVO prediction scales since the NIHSS scores were documented in hospitals during a clinical trial rather than in the prehospital setting. Inclusion of lower NIHSS or more distal LVO patients would lower sensitivities further. Selecting even higher scale thresholds for LVO triage would lead to many missed LVO strokes.

Background:EXCELLENT (NCT03685578) is a large, prospective, single-arm, multicenter, international registry of mechanical thrombectomy (MT) with EmboTrap as the first attempted device in routine clinical practice. The study collects per pass data on procedural and technical details that are based on interventionalists’ preference, providing an opportunity to assess current practices in MT across multiple international high-volume stroke centers.Methods:Subjects treated according to standard of care were eligible for inclusion in the study if EmboTrap was used in the first MT pass. Interim analysis focusing on procedural details and per pass clot retrieval technique was performed based on 689 subjects enrolled by 79 physicians across 26 international sites (US, Belgium, Germany, France) between Sept 2018 and Jul 2020.Results:Mean #passes was 2.1 (median=1, max=10), 50.3% subjects had only 1 pass and 84.8% had 3 or fewer. Per pass use of stent retriever, aspiration, balloon guide, intermediate catheter and long sheath catheter, along with technique details (e.g. incubation time, device positioning, co-aspiration) are summarized in Table 1. Rates and reasons for device changes are also given.Conclusion:Interim analysis of the ongoing EXCELLENT registry informs on current practice patterns in MT. This is the first report of detailed per pass clot retrieval strategies in a large international multicenter cohort.