Strokes Averted by Intravenous Thrombolysis: A Secondary Analysis of a Prospective, Multicenter, Controlled Trial of Mobile Stroke Units.

OBJECTIVE: This study was undertaken to examine averted stroke in optimized stroke systems. METHODS: This secondary analysis of a multicenter trial from 2014 to 2020 compared patients treated by mobile stroke unit (MSU) versus standard management. The analytical cohort consisted of participants with suspected stroke treated with intravenous thrombolysis. The main outcome was a tissue-defined averted stroke, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours attributed to thrombolysis and no acute infarction/hemorrhage on imaging. An additional outcome was stroke with early symptom resolution, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours attributed to thrombolysis. RESULTS: Among 1,009 patients with a median last known well to thrombolysis time of 87 minutes, 159 (16%) had tissue-defined averted stroke and 276 (27%) had stroke with early symptom resolution. Compared with standard management, MSU care was associated with more tissue-defined averted stroke (18% vs 11%, adjusted odds ratio [aOR] = 1.82, 95% confidence interval [CI] = 1.13-2.98) and stroke with early symptom resolution (31% vs 21%, aOR = 1.74, 95% CI = 1.12-2.61). The relationships between thrombolysis treatment time and averted/early recovered stroke appeared nonlinear. Most models indicated increased odds for stroke with early symptom resolution but not tissue-defined averted stroke with earlier treatment. Additionally, younger age, female gender, hyperlipidemia, lower National Institutes of Health Stroke Scale, lower blood pressure, and no large vessel occlusion were associated with both tissue-defined averted stroke and stroke with early symptom resolution. INTERPRETATION: In optimized stroke systems, 1 in 4 patients treated with thrombolysis recovered within 24 hours and 1 in 6 had no demonstrable brain injury on imaging. ANN NEUROL 2024;95:347-361.

Tenzing 7 delivery catheter with or without a leading microwire for single pass aspiration thrombectomy: A multicenter experience.

INTRODUCTION: Aspiration mechanical thrombectomy traditionally includes use of an inner microcatheter and leading microwire to navigate an aspiration catheter (AC) to the site of occlusion. Early clinical experience suggests that a leading microwire is often not needed with the Tenzing 7 (T7, Route 92 Medical, San Mateo, CA), a soft tapered tip ledge-reducing delivery catheter. This multicenter experience aims to describe AC delivery success in single-pass thrombectomy using T7 with and without a leading microwire. METHODS: A retrospective review was conducted of consecutive patients who underwent single-pass thrombectomy with T7 at six institutions between 2020 and 2022. We examined the percentage of successful AC delivery, puncture-to-revascularization time, and procedural complication rate. RESULTS: A leading microwire with T7 was used in 19/89 (21%) of patients, and it was not used with T7 in 70/89 (79%) of patients. Successful AC delivery was similar with and without microwires (97% vs. 90%, p = 0.15). Median puncture-to-revascularization times were similar (17 min microwire vs. 16 min no-microwire, p = 0.12). No complications were associated with microwire use; one (1.4%) patient had a T7-related vasospasm resolved with verapamil during thrombectomy without a leading microwire. Differences in complication rates were not statistically significant (p = 0.46). CONCLUSION: In our real-world clinical experience, leading microwire use was infrequently necessary with the T7 delivery catheter. Successful AC delivery and complication rates were similar with and without microwire use in single-pass T7 thrombectomies. Initial pass with T7 may be performed without use of leading microwire, reserving microwire use for refractory cases or known difficult-to-navigate vasculature.

Outcomes of patients with pre-existing disability managed by mobile stroke units: A sub-analysis of the BEST-MSU study.

BACKGROUND: Few data exist on acute stroke treatment in patients with pre-existing disability (PD) since they are usually excluded from clinical trials. A recent trial of mobile stroke units (MSUs) demonstrated faster treatment and improved outcomes, and included PD patients. AIM: To determine outcomes with tissue plasminogen activator (tPA), and benefit of MSU versus management by emergency medical services (EMS), for PD patients. METHODS: Primary outcomes were utility-weighted modified Rankin Scale (uw-mRS). Linear and logistic regression models compared outcomes in patients with versus without PD, and PD patients treated by MSU versus standard management by EMS. Time metrics, safety, quality of life, and health-care utilization were compared. RESULTS: Of the 1047 tPA-eligible ischemic stroke patients, 254 were with PD (baseline mRS 2-5) and 793 were without PD (baseline mRS 0-1). Although PD patients had worse 90-day uw-mRS, higher mortality, more health-care utilization, and worse quality of life than non-disabled patients, 53% returned to at least their baseline mRS, those treated faster had better outcome, and there was no increased bleeding risk. Comparing PD patients treated by MSU versus EMS, 90-day uw-mRS was 0.42 versus 0.36 (p = 0.07) and 57% versus 46% returned to at least their baseline mRS. There was no interaction between disability status and MSU versus EMS group assignment (p = 0.67) for 90-day uw-mRS. CONCLUSION: PD did not prevent the benefit of faster treatment with tPA in the BEST-MSU study. Our data support inclusion of PD patients in the MSU management paradigm.

Improved catheter delivery for aspiration thrombectomy using Tenzing 7 ledge reducing catheter and FreeClimb 70.

PURPOSE: Previous comparative mechanical thrombectomy device trials reported a substantial crossover rate from first-line aspiration to stent-retriever thrombectomy. A specialized delivery catheter may help track large-bore aspiration catheters to target occlusions. We report our multicenter experience of aspiration thrombectomy of intracranial large vessel occlusions using the FreeClimbTM 70 and Tenzing® 7 delivery catheter (Route 92, San Mateo, CA). METHODS: After local Institutional Review Board approval, we retrospectively reviewed the clinical, procedural, and imaging data of patients who underwent mechanical thrombectomy with the FreeClimb 70 and Tenzing 7. RESULTS: FreeClimb 70 was successfully delivered using Tenzing 7 to target occlusion in 30/30 (100%) patients (18 M1, 6 M2, 4 ICA-terminus, and 2 basilar artery occlusions), without the use of a stent-retriever for anchoring. In 21/30 (70%) cases, a leading microwire was not needed to advance the Tenzing 7 to the target. Median (interquartile range) time from groin puncture to first pass was 12 (interquartile range 8-15) minutes. Overall first pass effect, or first pass effect (modified thrombolysis in cerebral ischemia 2C-3), was achieved 16/30 (53%). For M1 occlusions, first pass effect was 11/18 (61%). Successful reperfusion (modified thrombolysis in cerebral ischemia ≥ 2B) was achieved in 29/30 (97%) cases after a median of 1 pass (interquartile range 1-3). Median groin puncture to reperfusion time was 16 (interquartile range 12-26) minutes. There were no procedural complications or symptomatic intracranial hemorrhage. Average improvement in National Institutes of Health Stroke Scale at discharge was 6.6 ± 7.1. There were three patient deaths (renal failure, respiratory failure, and comfort care). CONCLUSIONS: Initial data support the use of Tenzing 7 with FreeClimb 70 catheter for reliable access to rapid, effective, and safe aspiration thrombectomy of large vessel occlusions.

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.

AXS Vecta 0.071-0.074 Inch Aspiration Catheters for Mechanical Thrombectomy: Case Series and Literature Review.

Aspiration catheters are widely used for thrombectomy either alone or in combination with a stent-retriever, with a distal inner diameter and trackability keys to their success. In an illustrative case series, we report our clinical experience with AXS Vecta (Stryker Neurovascular, Fremont, CA, USA), available in both 0.071-inch and 0.074-inch distal inner diameters, including the first 2 Vecta 74 cases reported. A literature review on AXS Vecta is also provided. In our series, 9 thrombectomies were performed (Vecta 71: 2 M1, 5 M2 occlusions; Vecta 74: 1 M1 and 1 ICA-terminus occlusion). The AXS Vecta was successfully delivered to the target site in all cases. In 7 of 9 cases, the catheter was delivered over a Tenzing 7 delivery catheter (Route 92 Medical, San Mateo, CA, USA). For 2 of 9 combination approach cases, Vecta was delivered using the stent-retriever wire as a rail. The median improvement in NIHSS score during hospitalization was 9 (IQR 5-12). Successful mTICI 2C or 3 recanalization was achieved in 8 of 9 (89%) patients after a median 2 (IQR 1-2) passes. Our median groin-to-reperfusion time was 23 (IQR 12.5-32) minutes, with no procedural complications. Two previous clinical studies of a total of 29 patients treated with Vecta 71 reported successful mTICI 2b-3 recanalization in 89-90% of cases. The Median groin-to-reperfusion time was 30 minutes. Complications were seen in 2 of 29 (6.9%) cases (vessel perforation and/or intracerebral hemorrhage). These data support the efficacy, deliverability, and safety of AXS Vecta for mechanical thrombectomy.

Intravenous alteplase has different effects on the efficacy of aspiration and stent retriever thrombectomy: analysis of the COMPASS trial.

BACKGROUND: There is conflicting evidence on the utility of intravenous (IV) alteplase in patients with emergent large vessel occlusion (ELVO) treated with mechanical thrombectomy (MT). METHODS: This was a post hoc analysis of the COMPASS: a trial of aspiration thrombectomy versus stent retriever thrombectomy as first-line approach for large vessel occlusion. We compared clinical, procedural and angiographic outcomes of patients with and without prior IV alteplase administration. RESULTS: In the COMPASS trial, 235 patients had presented to the hospital within the first 4 hours of stroke symptom onset and were eligible for analysis. On univariate analysis, administration of IV alteplase prior to MT was found to be significantly associated with favorable outcomes (modified Rankin scale (mRS) 0-2 at 3 months; 55.6% vs 40.0% in the MT-only group, P=0.037). However, on multivariate analysis, only baseline (pre-stroke) mRS, admission National Institutes of Health Stroke Scale (NIHSS) score and age were identified as independent predictors of favorable outcomes at 3 months. We found higher final thrombolysis in cerebral infarction (TICI) 2b/3 rates in patients without the use of alteplase prior to the aspiration first approach (100.0% vs 87.9% in IV altepase +aspiration first MT, P=0.03). In the stent retriever first group, final TICI 2b/3 rates were identical in patients with and without IV alteplase administration (87.5% and 87.5%, P=1.0). CONCLUSIONS: Prior administration of IV alteplase may adversely affect the efficacy of aspiration, but does not seem to influence the stent retriever first approach to MT in patients with anterior circulation ELVO.

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.

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.

Prospective, Multicenter, Controlled Trial of Mobile Stroke Units.

BACKGROUND: Mobile stroke units (MSUs) are ambulances with staff and a computed tomographic scanner that may enable faster treatment with tissue plasminogen activator (t-PA) than standard management by emergency medical services (EMS). Whether and how much MSUs alter outcomes has not been extensively studied. METHODS: In an observational, prospective, multicenter, alternating-week trial, we assessed outcomes from MSU or EMS management within 4.5 hours after onset of acute stroke symptoms. The primary outcome was the score on the utility-weighted modified Rankin scale (range, 0 to 1, with higher scores indicating better outcomes according to a patient value system, derived from scores on the modified Rankin scale of 0 to 6, with higher scores indicating more disability). The main analysis involved dichotomized scores on the utility-weighted modified Rankin scale (≥0.91 or <0.91, approximating scores on the modified Rankin scale of ≤1 or >1) at 90 days in patients eligible for t-PA. Analyses were also performed in all enrolled patients. RESULTS: We enrolled 1515 patients, of whom 1047 were eligible to receive t-PA; 617 received care by MSU and 430 by EMS. The median time from onset of stroke to administration of t-PA was 72 minutes in the MSU group and 108 minutes in the EMS group. Of patients eligible for t-PA, 97.1% in the MSU group received t-PA, as compared with 79.5% in the EMS group. The mean score on the utility-weighted modified Rankin scale at 90 days in patients eligible for t-PA was 0.72 in the MSU group and 0.66 in the EMS group (adjusted odds ratio for a score of ≥0.91, 2.43; 95% confidence interval [CI], 1.75 to 3.36; P<0.001). Among the patients eligible for t-PA, 55.0% in the MSU group and 44.4% in the EMS group had a score of 0 or 1 on the modified Rankin scale at 90 days. Among all enrolled patients, the mean score on the utility-weighted modified Rankin scale at discharge was 0.57 in the MSU group and 0.51 in the EMS group (adjusted odds ratio for a score of ≥0.91, 1.82; 95% CI, 1.39 to 2.37; P<0.001). Secondary clinical outcomes generally favored MSUs. Mortality at 90 days was 8.9% in the MSU group and 11.9% in the EMS group. CONCLUSIONS: In patients with acute stroke who were eligible for t-PA, utility-weighted disability outcomes at 90 days were better with MSUs than with EMS. (Funded by the Patient-Centered Outcomes Research Institute; BEST-MSU ClinicalTrials.gov number, NCT02190500.).

Prestroke Disability and Outcome After Thrombectomy for Emergent Anterior Circulation Large Vessel Occlusion Stroke.

BACKGROUND AND OBJECTIVES: To determine the impact of endovascular therapy for large vessel occlusion stroke in patients with vs those without premorbid disability. METHODS: We performed a post hoc analysis of the TREVO Stent-Retriever Acute Stroke (TRACK) Registry, which collected data on 634 consecutive patients with stroke treated with the Trevo device as first-line endovascular thrombectomy (EVT) at 23 centers in the United States. We included patients with internal carotid or middle cerebral (M1/M2 segment) artery occlusions, and the study exposure was patient- or caregiver-reported premorbid modified Rank Scale (mRS) score ≥2 (premorbid disability [PD]) vs premorbid mRS score of 0 to 1 (no PD [NPD]). The primary outcome was no accumulated disability, defined as no increase in 90-day mRS score from the patient's premorbid mRS score. RESULTS: Of the 634 patients in TRACK, 407 patients were included in our cohort, of whom 53 (13.0%) had PD. The primary outcome of no accumulated disability was achieved in 37.7% (20 of 53) of patients with PD and 16.7% (59 of 354) of patients with NPD (p < 0.001), while death occurred in 39.6% (21 of 53) and 14.1% (50 of 354) (p < 0.001), respectively. The adjusted odds ratio of no accumulated disability for patients with PD was 5.2 (95% confidence interval [CI] 2.4-11.4, p < 0.001) compared to patients with NPD. However, the adjusted odds ratio for death in patients with PD was 2.90 (95% CI 1.38-6.09, p = 0.005). DISCUSSION: In this study of patients with anterior circulation acute ischemic stroke treated with EVT, we found that PD was associated with a higher probability of not accumulating further disability compared to patients with NPD but also with higher probability of death. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that in anterior circulation acute ischemic stroke treated with EVT, patients with PD compared to those without disability were more likely not to accumulate more disability but were more likely to die.

Intraoperative vascular complications during 2278 cerebral endovascular procedures with multimodality IONM: relationship between signal change, complication, intervention and postoperative outcome.

BACKGROUND: Intraoperative neuromonitoring (IONM) is often used during cerebral endovascular procedures. OBJECTIVE: To investigate the relationship between intraoperative vascular complications and IONM signal changes, and the impact of interventions on signal resolution and postoperative outcomes. METHODS: A series of 2278 cerebral endovascular procedures conducted under general anesthesia and using electroencephalography and somatosensory evoked potential monitoring were retrospectively reviewed. A subset of 763 procedures also included motor evoked potentials (MEPs). IONM alerts were categorized as either a partial attenuation or complete loss of signal. Vascular complications were subcategorized as due to rupture, emboli, instrumentation, or vasospasm. Odds ratios (ORs) for new postoperative motor deficits were calculated and diagnostic accuracy was measured using sensitivity, specificity, and likelihood ratios. RESULTS: The overall incidence of new postoperative motor deficit was 1.2%; 20.4% in cases with an IONM alert and 0.09% in cases without an alert. Relative to procedures with no alerts, odds of a new deficit increased if there was partial signal attenuation (OR=210.9, 95% CI 44.3 to 1003.5, p<0.0001) and increased further with complete loss of signal (OR=1437.3, 95% CI 297.3 to 6948.2, p<0.0001). Relative to procedures with unresolved alerts, odds of a new deficit decreased if the alert was fully resolved (OR=0.039, 95% CI 0.005 to 0.306, p<0.002). Procedures using MEPs had slightly higher sensitivity (92.3% vs 85.7%) but slightly lower specificity (96.7% vs 98.2%). CONCLUSIONS: An IONM alert associated with an arterial complication is associated with a dramatic increase in odds of a new postoperative deficit; however, if there is resolution of the alert prior to closure, odds of a new deficit decrease significantly.

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.

Stroke Imaging Selection Modality and Endovascular Therapy Outcomes in the Early and Extended Time Windows.

BACKGROUND AND PURPOSE: Advanced imaging has been increasingly used for patient selection in endovascular stroke therapy. The impact of imaging selection modality on endovascular stroke therapy clinical outcomes in extended time window remains to be defined. We aimed to study this relationship and compare it to that noted in early-treated patients. METHODS: Patients from a prospective multicentric registry (n=2008) with occlusions involving the intracranial internal carotid or the M1- or M2-segments of the middle cerebral arteries, premorbid modified Rankin Scale score 0 to 2 and time to treatment 0 to 24 hours were categorized according to treatment times within the early (0-6 hour) or extended (6-24 hour) window as well as imaging modality with noncontrast computed tomography (NCCT)±CT angiography (CTA) or NCCT±CTA and CT perfusion (CTP). The association between imaging modality and 90-day modified Rankin Scale, analyzed in ordinal (modified Rankin Scale shift) and dichotomized (functional independence, modified Rankin Scale score 0-2) manner, was evaluated and compared within and across the extended and early windows. RESULTS: In the early window, 332 patients were selected with NCCT±CTA alone while 373 also underwent CTP. After adjusting for identifiable confounders, there were no significant differences in terms of 90-day functional disability (ordinal shift: adjusted odd ratio [aOR], 0.936 [95% CI, 0.709-1.238], P=0.644) or independence (aOR, 1.178 [95% CI, 0.833-1.666], P=0.355) across the CTP and NCCT±CTA groups. In the extended window, 67 patients were selected with NCCT±CTA alone while 180 also underwent CTP. No significant differences in 90-day functional disability (aOR, 0.983 [95% CI, 0.81-1.662], P=0.949) or independence (aOR, 0.640 [95% CI, 0.318-1.289], P=0.212) were seen across the CTP and NCCT±CTA groups. There was no interaction between the treatment time window (0-6 versus 6-24 hours) and CT selection modality (CTP versus NCCT±CTA) in terms of functional disability at 90 days (P=0.45). CONCLUSIONS: CTP acquisition was not associated with better outcomes in patients treated in the early or extended time windows. While confirmatory data is needed, our data suggests that extended window endovascular stroke therapy may remain beneficial even in the absence of advanced imaging.

Clot perviousness is associated with first pass success of aspiration thrombectomy in the COMPASS trial.

BACKGROUND: Clot density (Hounsfield units, HU) and perviousness (post-contrast increase in the HU of clot) are thought to be associated with clot composition. We evaluate whether these imaging characteristics were associated with angiographic outcomes of aspiration and stent retriever thrombectomy in COMPASS: a trial of aspiration thrombectomy versus stent retriever thrombectomy as first-line approach for large vessel occlusion. METHODS: Clot density and perviousness were measured by two independent operators who were blind to all the final angiographic and clinical outcomes. The association of clot density and perviousness with the Thrombolysis In Cerebral Infarction (TICI) scale after first pass was assessed using univariate and multivariate analysis. RESULTS: Among all patients enrolled in COMPASS, 165 were eligible for the post-hoc analysis (81 patients in the aspiration first and 84 in the stent retriever first groups). Overall mean perviousness of clot was significantly higher in patient with mTICI 2b-3 after first pass (28.6±22.9 vs 20.3±19.2, p=0.017). Mean perviousness among patients who achieved TICI 2c/3 versus TICI 2b versus TICI 0-2a in the aspiration first group varied significantly (32.6±26.1, 35.3±24.4, and 17.7±13.1, p=0.013). The association of perviousness with first pass success was not significant in the stent retriever group. Using multivariate analysis, high perviousness (defined as cut-off >27.6) was an independent predictor of TICI 2b-3 (OR 3.82, 95% CI 1.10 to 13.19; p=0.034). CONCLUSIONS: Clot perviousness is associated with first pass angiographic success in patients treated with the aspiration first approach for thrombectomy.

The novel Tenzing 7 delivery catheter designed to deliver intermediate catheters to the face of embolus without crossing: clinical performance predicted in anatomically challenging model.

BACKGROUND: In large vessel occlusionstroke, navigation of aspiration catheters (AC) can be impeded by vessel tortuosity and the ophthalmic artery origin. A novel tapered delivery catheter was designed to facilitate delivery without disturbing the embolus. We assessed AC deliverability in vitro and validated the observations in a first-in-human experience. METHODS: In a vascular model with three challenging craniocervical scenarios, two commercial AC were advanced from the carotid to the middle cerebral artery by four neurointerventionalists. Catheter deliverability with standard microwire and microcatheter (MC) combinations and the Tenzing 7 (T7) Delivery Catheter (Route 92 Medical, San Mateo, CA) were compared. Operators rated aspects of catheter deliverability on a 5-point scale. Results were compared with device delivery patterns at a neurovascular center before and after clinical introduction of T7. RESULTS: In vitro, success rate and speed were higher with T7 (96%; mean 30±10 s) than with MC (65%; 72±47 s, p<0.001 each), with fewer interactions with the occlusion site (T7: 54% vs MC: 77%, p=0.004). T7 received superior ratings regarding carotid artery deflection (T7: 2, IQR1-3 vs MC: 3, IQR2-3, p<0.001), guide catheter pushback (T7: 2, IQR1-3 vs MC: 3, IQR3-3, p<0.001) and ophthalmic artery passage (T7: 1.5, IQR1-2 vs MC: 4, IQR3-5, p<0.001). Before introduction of T7 at a single center, delivery of AC to a large vessel occlusion without crossing was achieved in 15/123 cases (12%). With T7, this rate was 28/31 patients (90.3%). CONCLUSION: Compared with microcatheter and microwire combinations, T7 improves aspiration catheter delivery in vitro, minimizing the need to cross the occlusion. Initial clinical experience appears to validate the model's observations.

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.

First Pass Effect in Patients Treated With the Trevo Stent-Retriever: A TRACK Registry Study Analysis.

Background and Objective: The first pass effect (FPE; achieving complete recanalization with a single thrombectomy device pass) has been shown to be associated with higher rates of good clinical outcomes in patients with acute ischemic stroke. Here, we investigate clinical and radiographic factors associated with FPE in a large U.S. post-marketing registry (TRACK, Trevo Stent-Retriever Acute Stroke). Methods: We analyzed the TRACK database (multicenter registry of 634 patients from 23 centers from March 2013 through August 2015), which 609 patients were included in the final analysis. FPE was defined as a single pass/use of device, TICI 2c/3 recanalization, and no use of rescue therapy. Analysis of individual patient data from TRACK were performed to analyze clinical and radiographic characteristics associated with FPE as well-compared clinical outcomes defined as modified Rankin Scale (mRS) score at 30 and 90 days from hospital discharge to the non-FPE group. Results: The rate of FPE in TRACK was 23% (140/609). There was no association between patient demographics and FPE, including age (p = 0.36), sex (p = 0.50), race (p = 0.50), location of occlusion (p = 0.26), baseline NIHSS (p = 0.62), or past medical history. There was no difference in the use of a balloon-guide catheter or general anesthesia (49 and 57% with FPE vs. 47 and 64%, p = 0.63 and p = 0.14, respectively). Clinical outcomes were significantly associated with FPE; 63 vs. 44% in non-FPE patients achieved mRS 0-2 at 90 days (p = 0.0004). Conclusion: Our study showed that achieving complete recanalization with a single thrombectomy pass using the Trevo device was highly beneficial. The most common clinical factors that are used to determine eligibility for endovascular therapy, such as NIHSS severity, location of occlusion or patient age were not predictive of the ability to achieve FPE.

An international multicenter retrospective study to survey the landscape of thrombectomy in the treatment of anterior circulation acute ischemic stroke: outcomes with respect to age.

BACKGROUND: Thrombectomy is an efficacious treatment for acute ischemic stroke (AIS). However, relatively few studies to date have specifically examined the impact and clinical implications of age on outcomes for thrombectomy in anterior AIS. OBJECTIVE: To provide a snapshot of patient metrics and outcomes with respect to age following thrombectomy for anterior AIS to supplement the current body of data for predictors of clinical outcomes in a real-world setting. METHODS: Data were collected for 20 consecutive patients with AIS treated with thrombectomy at 15 high-volume stroke centers across North America between 2015 and 2016. Patients with anterior occlusions were dichotomized based on whether they were older or younger than 80 years. Ordinal logistic regression analyzed how clinical variables impacted disability using 90-day modified Rankin Scale (mRS) scores. RESULTS: Adequate revascularization (TICI ≥2B) was achieved in 92.3% of patients aged <80 years with an average 1.7±0.1 passes taken with the primary technique and in 88.0% of patients aged ≥80 years with an average 1.7±0.2 passes. Despite similar baseline characteristics, mRS scores were significantly higher in older patients postoperatively and at 90 days after intervention. Age was a significant predictor of 90-day mRS across the study population. CONCLUSION: This analysis affirms age is a significant determinant of 90-day mRS scores following thrombectomy for large vessel anterior AIS. Further investigation into risks faced by elderly patients during thrombectomy may provide actionable information to help refine patient selection and improve outcomes.

Site Experience and Outcomes in the Trevo Acute Ischemic Stroke (TRACK) Multicenter Registry.

Background and Purpose- It remains unclear how experience influences outcomes after the advent of stent retriever technology. We studied the relationship between site experience and outcomes in the Trevo Acute Ischemic Stroke multicenter registry. Methods- The 24 sites that enrolled patients in the Trevo Acute Ischemic Stroke registry were trichotomized into low-volume (<2 cases/month), medium-volume (2-4 cases/month), and high-volume centers (>4 cases/month). Baseline features, imaging, and clinical outcomes were compared across the 3 volume strata. A multivariable analysis was performed to assess whether outcomes were influenced by site volumes. Results- A total of 624 patients were included and distributed as low- (n=188 patients, 30.1%), medium- (n=175, 28.1%), and high-volume (n=261, 41.8%) centers. There were no significant differences in terms of age (mean, 66±16 versus 67±14 versus 65±15; P=0.2), baseline National Institutes of Health Stroke Scale (mean, 17.6±6.5 versus 16.8±6.5 versus 17.6±6.9; P=0.43), or occlusion site across the 3 groups. Median (interquartile range) times from stroke onset to groin puncture were 266 (181.8-442.5), 239 (175-389), and 336.5 (221.3-466.5) minutes in low-, medium-, and high-volume centers, respectively (P=0.004). Higher efficiency and better outcomes were seen in higher volume sites as demonstrated by shorter procedural times (median, 97 versus 67 versus 69 minutes; P<0.001), higher balloon guide catheter use (40% versus 36% versus 59%; P≤0.0001), and higher rates of good outcome (90-day modified Rankin Scale [mRS], ≤2; 39% versus 50% versus 53.4%; P=0.02). There were no appreciable differences in symptomatic intracranial hemorrhage or 90-day mortality. After adjustments in the multivariable analysis, there were significantly higher chances of achieving a good outcome in high- versus low-volume (odds ratio, 1.67; 95% CI, 1.03-2.7; P=0.04) and medium- versus low-volume (odds ratio, 1.75; 95% CI, 1.1-2.9; P=0.03) centers, but there were no significant differences between high- and medium-volume centers (P=0.86). Conclusions- Stroke center volumes significantly influence efficiency and outcomes in mechanical thrombectomy.