Multicenter comparison of Chiari malformation type I presentation in children versus adults

OBJECTIVE

Treatment for Chiari malformation type I (CM-I) often includes surgical intervention in both pediatric and adult patients. The authors sought to investigate fundamental differences between these populations by analyzing data from pediatric and adult patients who required CM-I decompression.

METHODS

To better understand the presentation and surgical outcomes of both groups of patients, retrospective data from 170 adults and 153 pediatric patients (2000-2019) at six institutions were analyzed.

RESULTS

The adult CM-I patient population requiring surgical intervention had a greater proportion of female patients than the pediatric population (p < 0.0001). Radiographic findings at initial clinical presentation showed a significantly greater incidence of syringomyelia (p < 0.0001) and scoliosis (p < 0.0001) in pediatric patients compared with adult patients with CM-I. However, presenting signs and symptoms such as headaches (p < 0.0001), ocular findings (p = 0.0147), and bulbar symptoms (p = 0.0057) were more common in the adult group. After suboccipital decompression procedures, 94.4% of pediatric patients reported symptomatic relief compared with 75% of adults with CM-I (p < 0.0001).

CONCLUSIONS

Here, the authors present the first retrospective evaluation comparing adult and pediatric patients who underwent CM-I decompression. Their analysis reveals that pediatric and adult patients significantly differ in terms of demographics, radiographic findings, presentation of symptoms, surgical indications, and outcomes. These findings may indicate different clinical conditions or a distinct progression of the natural history of this complex disease process within each population, which will require prospective studies to better elucidate.

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.

A Systematic Review of Non-Opioid Pain Management in Chiari Malformation (Type 1) Patients: Current Evidence and Novel Therapeutic Opportunities

Chiari Malformation Type I (CM) includes a range of cranial abnormalities at the junction of the skull with the spine, with common symptoms including pain and headaches. Currently, CM pain is managed medically through anti-inflammatory drugs, muscle relaxants, and opioids, while surgical management includes posterior fossa decompression. Given the adverse effects of opioid use, and an ongoing opioid epidemic, there is a need for safe, non-opioid alternatives for clinical pain management. This systematic review was performed to provide an update on the current literature pertaining to the treatment of CM pain with non-opioid alternatives. A literature search was performed in June 2022 utilizing the PubMed and Google Scholar databases, and articles were identified that included information regarding non-opioid pain management in CM patients. A total of 90 articles were obtained from this search, including 10 relevant, drug-specific studies. Two independent reviewers selected and included all relevant articles based on the chosen search criteria to minimize bias risk. Currently available treatments for neurosurgical pain management include anticonvulsants, corticosteroids, NSAIDs, anti-inflammatory drugs, NMDA receptor antagonists, local anesthetics, nerve blocks, scalp blocks, and neuromuscular blocks. While more information is needed on the use of non-opioid pain management, the present literature provides potential evidence of its efficacy amongst the CM patient population, on account of the success that non-opioid pain management has demonstrated within other neurological pain syndromes. Further research into non-pharmacological pain management would also benefit the CM population and could be generalized to related conditions.

Stroke thrombolysis given by emergency physicians: The time is here

Emergency Medicine core clinical privileges include administration of thrombolytic therapy for myocardial infarction and stroke. However, emergency medicine providers have created their own paradigm to rely on neurology specialty consultation to treat acute stroke patients. A 2013 study supported by the American Academy of Neurology showed an 11% shortage of neurologists at that time and projected a 19% shortage by 2025. The lack of neurologists is a worldwide problem. To help ease the shortage, teleneurology and telestroke care has been implemented by neurologists, most notably for acute ischemic stroke (AIS) patients. We present a model in which an Emergency Medicine (EM) Stroke Champion (SC); an EM physician within our Neurologic Emergency Department, directs care for acute stroke patients at our comprehensive hub and primary stroke center spoke hospitals. The SCs independently treat patients with fibrinolytic therapy and provide teleneurology to fellow emergency physicians caring for acute stroke patients at spoke hospitals. Over nineteen months the SCs received 457 phone calls for patients meeting stroke alert criteria. Sixteen patients were deemed eligible for IV alteplase with one hemorrhagic conversion (6.25%). Sixty-four patients required transfer, and this was facilitated by the SCs. The concept of emergency physician SCs providing teleneurology consultation to other fellow emergency physicians was found to be feasible and safe. This model has the potential to be generalized not to just stroke champions, but to all emergency physicians to feel both confident and comfortable treating acute stroke patients.

Abstract TMP36: Improve Patient Outcomes In A Specialized Neurological Emergency Department

Improved Patient Outcomes In A Specialized Neurological Emergency Department

Introduction: Stroke is now the fifth leading cause of death in the U.S., but remains the leading cause of long term disability. Target: Stroke helps hospitals achieve improved stroke outcomes through reduced door-to-needle times for eligible stroke patients. Phase III of the American Heart Association/American Stroke Association initiative set more aggressive targets for timely treatment with IV alteplase. To achieve rapid treatment times and better patient outcomes, we created a neurologic emergency department (Neuro ED). Neuro ED hours are staffed by emergency physicians with specialized neuroscience training and administer IV alteplase independently, compared to the traditional ED (TED) where emergency providers consult neurology.

Methods: This is a retrospective observational study from 2019-2021 comparing outcomes of acute ischemic stroke patients who received IV alteplase following implementation of the Neuro ED compared to a TED. The following metrics were calculated for each patient: Door to Needle times (DTN), door to CT times (DTCT), and pre and post National Institute of Health Stroke Scale (NIHSS)

Results: 74 patients were treated in the Neuro ED and 45 patients were treated in the TED. Average DTN times in the Neuro ED were 27 minutes compared to 65 minutes in the TED. Patients treated in the Neuro ED achieved DTN times of 45 min or less 87% of cases, while only 24% of the time in the TED. Patients treated in the Neuro ED achieved DTN times of 30 min or less 65% of cases, with only 4% of cases in the TED. Average DTCT times in the Neuro ED were 8 minutes faster than the TED. No differences in admission NIHSS were found with an average of 8.75, but a significant improvement was found in discharge NIHSS. Average discharge NIHSS was 3.8 for Neuro ED stroke patients compared with 5.6 for TED patients (p<0.001).

Conclusion: Implementation of a Neuro ED led to swift management and improved symptoms for stroke patients. A dedicated Neuro ED is highly effective in improving DTN times, DTCT times, and overall stroke outcomes.

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.

Placement of a Pipeline Embolization Device: 2-Dimensional Operative Video

Flow diversion has been a game-changer in the treatment of wide-neck large and giant cavernous and supraclinoid internal carotid artery (ICA) aneurysms as well as large vertebral artery aneurysms. Prior to their existence, carotid sacrifice or clipping with or without external to internal carotid artery bypass was the mainstay of treatment. Prior to flow diversion, endovascular coil embolization was often not effective as a stand-alone treatment because of the fact that many of these aneurysms present with symptoms created by mass effect on the cavernous sinus cranial nerves by the aneurysm. Packing the aneurysm with coils did nothing to alleviate the mass effect and did not prevent flow from entering the aneurysm. The continued flow causes coil compaction and aneurysm enlargement. Flow diversion addressed both these issues by diverting flow from the aneurysm while allowing the aneurysm to slowly thrombose and shrink. The video is a step-by-step account of this procedure in a 72-yr-old male with a large recurrence of a previously coiled cavernous ICA aneurysm. The procedure was performed following informed consent.

The Use of Antiplatelet Agents and Heparin in the 24-Hour Postintravenous Alteplase Window for Neurointervention

BACKGROUND

Intravenous (IV) alteplase with mechanical thrombectomy has been found to be superior to alteplase alone in select patients with intracranial large vessel occlusion. Current guidelines discourage the use of antiplatelet agents or heparin for 24 h following alteplase. However, their use is often necessary in certain circumstances during thrombectomy procedures.

OBJECTIVE

To study the safety and outcomes in patients who received blood thinning medications for thrombectomy after IV Tissue-Type plasminogen activator (tPA).

METHODS

This is a multicenter retrospective review of the use of antiplatelet agents and/or heparin in patients within 24 h following tPA administration. Patient demographics, comorbidities, bleeding complications, and discharge outcomes were collected.

RESULTS

A series of 88 patients at 9 centers received antiplatelet medications and/or heparin anticoagulation following IV alteplase for revascularization procedures requiring stenting. The mean National Institutes of Health Stroke Scale (NIHSS) on admission was 14.6. Reasons for use of a stent included internal carotid artery occlusion in 74% of patients. Thrombolysis in cerebral infarction (TICI) 2b-3 revascularization was accomplished in 90% of patients. The rate of symptomatic intracranial hemorrhage (sICH) was 8%; this was not significantly different than the sICH rate for a matched group of patients not receiving antiplatelets or heparin during the same time frame. Functional independence at 90 d (modified Rankin Scale 0-2) was seen in 57.8% of patients. All-cause mortality was 12%.

CONCLUSION

The use of antiplatelet agents and heparin for stroke interventions following IV alteplase appears to be safe without significant increased risk of hemorrhagic complications in this group of patients when compared to control data and randomized controlled trials.

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.

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.

Abstract P168: Who Are You Going to Call?: Emergency Physician Stroke Champions

Introduction: A 2013 study supported by the American Academy of Neurology showed an 11% shortage of neurologists with a projected 19% shortage by 2025. An additional supply of 3000 neurologists is needed by 2025 to meet the looming demand. To help ease the shortage, teleneurology has been implemented by neurologists, mainly for acute stroke patients. We present our model of emergency physician Stroke Champions (SCs) to direct care for stroke patients.

Methods: Administering thrombolytics for stroke is a key component of emergency medicine core competencies. Our health system consists of 4 hospitals; a main hub and 3 spoke hospitals. The hub hospital innovatively developed a Neurologic Emergency Department (Neuro ED) with 5 board certified emergency physicians dedicated to caring for patients with any type of neurological complaint. The Neuro ED physicians are also designated as SCs that have specialized training to provide teleneurology to fellow emergency physicians caring for acute stroke patients at the additional hospitals. This supplementary training consists of a mini neurology fellowship with rotations through the neurologic ICU, specialized stroke floor, neurointerventional suite, and neuroradiology.

Results: Over a 90-day period the command center received 67 phone calls for patients that met stroke alert criteria. Calls entailed managing BP, dosing alteplase, and recommendations for advanced neuroimaging. Most importantly, the SCs extensively reviewed inclusion and exclusion criteria for IV alteplase with the spoke emergency physician. Three patients were deemed eligible for IV alteplase, with no cases of intracranial hemorrhage. Seven patients required transfer and was facilitated by the SCs, reducing any delays. Reasons for transfer included 3 cases of hemorrhagic stroke, 3 large vessel occlusions for mechanical thrombectomy - one of which received IV alteplase, and 1 brain tumor.

Conclusion: Teleneurology is a reliable means of reaching and treating stroke patients. With the severe current shortage of neurologists in the U.S., we now demonstrate a promising alternative of emergency physician Stroke Champions providing telestroke care. This model has produced a high success rate raising the standard of acute neurological care.

Abstract P467: Clinical Effectiveness of Endovascular Stroke Treatment in the Early and Extended Time Windows

Background and Purpose: The clinical efficacy of mechanical thrombectomy (MT) has been unequivocally demonstrated in multiple randomized clinical trials (RCTs). However, these studies were performed in carefully selected centers and utilized strict inclusion criteria. We aim to assess the clinical effectiveness of MT by comparing the specific RCT populations with corresponding patient cohorts derived from a prospective registry.

Methods: A total of 2008 patients from 76 sites across 12 countries were enrolled in a prospective open-label MT registry. Patients were categorized into the corresponding cohorts of the SWIFT-Prime, DAWN, and DEFUSE 3 trials based on the age, baseline NIHSS, occlusion site, IV tPA use, pre-morbid mRS and time to treatment criteria used in the RCTs 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 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 (mRS 0-2) in registry-derived patients were comparable to those of the patients treated in the corresponding RCTs (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 RCT controls (ordinal mRS shift 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 RCTs and strict guidelines.

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.

Ketogenic Diet for Malignant Gliomas: a Review

PURPOSE OF REVIEW

In this review, we examine the postulated mechanisms of therapeutic effect of ketogenic diets in the treatment of gliomas, review the completed clinical trials, and discuss further directions in this field.

RECENT FINDINGS

Cancers including gliomas are characterized by derangements in cellular metabolism. In vitro and animal studies have revealed that dietary interventions to reduce glucose and glycolytic pathways in gliomas may have a therapeutic effect. Early trials in patients with malignant gliomas have shown feasibility, but are not robust enough yet to demonstrate clinical applicability. Therapies for malignant gliomas of the brain are increasingly using a multi-targeted approach. The use of ketogenic diets and its variants may offer a unique and promising anti-glioma treatment by exploiting metabolic alterations seen in cancers including gliomas seen at the cellular level, which may work in concert with other therapies.

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-in-Human Experience With Integration of a Hydrocephalus Shunt Device Within a Customized Cranial Implant

BACKGROUND

Implantable shunt devices are critical and life saving for hydrocephalus patients. However, these devices are fraught with high complication rates including scalp dehiscence, exposure, and extrusion. In fact, high shunt valve profiles are correlated with increased complications compared to those with lower profiles. As such, we sought a new method for integrating shunt valves for those challenging patients presenting with scalp-related complications.

OBJECTIVE

To safely implant and integrate a hydrocephalus shunt valve device within a customized cranial implant, in an effort to limit its high-profile nature as a main contributor to shunt failure and scalp breakdown, and at the same time, improve patient satisfaction by preventing contour deformity.

METHODS

A 64-yr-old male presented with an extruding hydrocephalus shunt valve and chronic, open scalp wound. The shunt valve was removed and temporary shunt externalization was performed. He received 2 wk of culture-directed antibiotics. Next, a contralateral craniectomy was performed allowing a new shunt valve system to be implanted within a low-profile, customized cranial implant. All efforts were made, at the patient's request, to decrease the high-profile nature of the shunt valve contributing to his most recent complication.

RESULTS

First-in-human implantation was performed without complication. Postoperative shunt identification and programming was uncomplicated. The high-profile nature of the shunt valve was decreased by 87%. At 10 mo, the patient has experienced no complications and is extremely satisfied with his appearance.

CONCLUSION

This first-in-human experience suggests that a high-profile hydrocephalus shunt device may be safely integrated within a customized cranial implant.

Galenic Pial Arteriovenous Fistulas in Adults

BACKGROUND

Vein of Galen aneurysmal malformations (VOGMs) are pial arteriovenous fistulas possessing Galenic venous drainage most commonly presenting during the neonatal period and infancy, with initial discovery during adulthood quite rare.

OBJECTIVES AND METHODS

We conducted a literature survey of the PubMed database in order to identify Galenic pial arteriovenous fistulas (GPAVFs) with major manifestation or initial presentation during adulthood. Inclusionary criteria included pial AVFs with Galenic drainage with major manifestation or initial presentation at, or older than, 18 years. Exclusionary criteria included exclusive pediatric onset of symptomatology attributable to GPAVFs without a new onset major presentation during adulthood, exclusive or major dural arterial supply, arteriovenous malformations with Galenic drainage, developmental venous anomalies with Galenic drainage, isolated varices or anomalies of the vein of Galen, and any lesions with uncertainty regarding true GPAVF nature.

RESULTS

Our search generated 1589 articles. Excluding duplicates, 26 cases met criteria for evaluation. Mean age was 34.1 +/- 2.53 years. Clinical presentations of GPAVFs among adults included headache, intracranial hemorrhage, seizures, and focal neurologic deficits. Management strategies included observation (n = 5), emergent ventriculostomy or Torkildsen shunt (n = 3), cerebrospinal fluid diversion via ventriculoperitoneal shunting (n = 4), microsurgical obliteration or thrombectomy (n = 4), transarterial and/or transvenous embolotherapeutic obliteration (n = 7), and concurrent embolotherapy and radiosurgical irradiation (n = 1).

CONCLUSIONS

GPAVFs in adults often present with symptomatology of mild severity and may be effectively managed conservatively, though occasionally present catastrophically or may be treated via cerebrospinal fluid diversion, microsurgical obliteration, or endovascular embolization. Severity sufficient to require emergent intervention portended a poor outcome.

Delayed presentation of acute ischemic strokes during the COVID-19 crisis

BACKGROUND

The COVID-19 pandemic has disrupted established care paths worldwide. Patient awareness of the pandemic and executive limitations imposed on public life have changed the perception of when to seek care for acute conditions in some cases. We sought to study whether there is a delay in presentation for acute ischemic stroke patients in the first month of the pandemic in the US.

METHODS

The interval between last-known-well (LKW) time and presentation of 710 consecutive patients presenting with acute ischemic strokes to 12 stroke centers across the US were extracted from a prospectively maintained quality database. We analyzed the timing and severity of the presentation in the baseline period from February to March 2019 and compared results with the timeframe of February and March 2020.

RESULTS

There were 320 patients in the 2-month baseline period in 2019, there was a marked decrease in patients from February to March of 2020 (227 patients in February, and 163 patients in March). There was no difference in the severity of the presentation between groups and no difference in age between the baseline and the COVID period. The mean interval from LKW to the presentation was significantly longer in the COVID period (603±1035 min) compared with the baseline period (442±435 min, P<0.02).

CONCLUSION

We present data supporting an association between public awareness and limitations imposed on public life during the COVID-19 pandemic in the US and a delay in presentation for acute ischemic stroke patients to a stroke center.

Minimizing SARS-CoV-2 exposure when performing surgical interventions during the COVID-19 pandemic

BACKGROUND

Infection from the SARS-CoV-2 virus has led to the COVID-19 pandemic. Given the large number of patients affected, healthcare personnel and facility resources are stretched to the limit; however, the need for urgent and emergent neurosurgical care continues. This article describes best practices when performing neurosurgical procedures on patients with COVID-19 based on multi-institutional experiences.

METHODS

We assembled neurosurgical practitioners from 13 different health systems from across the USA, including those in hot spots, to describe their practices in managing neurosurgical emergencies within the COVID-19 environment.

RESULTS

Patients presenting with neurosurgical emergencies should be considered as persons under investigation (PUI) and thus maximal personal protective equipment (PPE) should be donned during interaction and transfer. Intubations and extubations should be done with only anesthesia staff donning maximal PPE in a negative pressure environment. Operating room (OR) staff should enter the room once the air has been cleared of particulate matter. Certain OR suites should be designated as covid ORs, thus allowing for all neurosurgical cases on covid/PUI patients to be performed in these rooms, which will require a terminal clean post procedure. Each COVID OR suite should be attached to an anteroom which is a negative pressure room with a HEPA filter, thus allowing for donning and doffing of PPE without risking contamination of clean areas.

CONCLUSION

Based on a multi-institutional collaborative effort, we describe best practices when providing neurosurgical treatment for patients with COVID-19 in order to optimize clinical care and minimize the exposure of patients and staff.

Should posterior cerebral artery occlusions be recanalized? Insights from the Trevo Registry

BACKGROUND AND PURPOSE

The purpose of this study was to evaluate the safety and effectiveness of mechanical thrombectomy (MT) in patients with acute ischaemic stroke related to isolated and primary posterior cerebral artery (PCA) occlusions amongst the patients enrolled in the multicentre post-market Trevo Registry.

METHOD

Amongst the 2008 patients enrolled in the Trevo Registry with acute ischaemic stroke due to large vessel occlusion treated by MT, 22 patients (1.1%) [10 females (45.5%), mean age 66.2 ± 14.3 years (range 28-91)] had a PCA occlusion [17 P1 (77.3%) and five P2 occlusions (22.7%)]. Recanalization after the first Trevo (Stryker, Fremont, CA, USA) pass and at the end of the procedure was rated using the modified Thrombolysis in Cerebral Infarction (mTICI) score. Procedure-related complications (i.e. groin puncture complication, perforation, symptomatic haemorrhage, embolus in a new territory) were also recorded. The modified Rankin Scale at 90 days was assessed.

RESULTS

Median National Institutes of Health Stroke Scale at admission was 14 (interquartile range 8-16). Stroke aetiology was cardio-embolic in 68.2% of cases. Half of the patients (11/22) received intravenous tissue plasminogen activator. 54.5% of the patients were treated under general anaesthesia. Reperfusion (i.e. mTICI 2b or 3) after first pass was obtained in 65% of cases. Final mTICI 2b-3 reperfusion was obtained in all cases. Only one (4.5%) procedure-related complication was recorded (puncture site) that resolved after surgery. At 90-day follow-up, modified Rankin Scale 0-2 was obtained in 59% of the patients and 9.1% died within the first 3 months after MT.

CONCLUSION

Mechanical thrombectomy for PCA occlusions seems to be safe (<5% procedure-related complications) and effective. Larger repository datasets are needed.

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.

Trevo 2000: Results of a Large Real-World Registry for Stent Retriever for Acute Ischemic Stroke

Background Recent randomized controlled trials show benefit of thrombectomy for large vessel occlusion in stroke. Real-world data aid in assessing reproducibility of outcomes outside of clinical trials. The Trevo Retriever Registry is a multicenter, international, prospective study designed to assess outcomes in a large cohort of patients. Methods and Results The Trevo Registry is a prospective database of patients with large vessel occlusion treated with the Trevo device as the first device. The primary end point is revascularization based on modified Thrombolysis in Cerebral Infarction score and secondary end points include 90-day modified Rankin Scale, 90-day mortality, neurological deterioration at 24 hours, and device/procedure related adverse events. Year 2008 patients were enrolled at 76 centers in 12 countries. Median admission National Institutes of Health Stroke Scale was 16 (interquartile range, 11-20). Occlusion sites were internal carotid artery (17.8%), middle cerebral artery (73.5%), posterior circulation (7.1%), and distal vascular locations (1.6%). A modified Thrombolysis in Cerebral Infarction 2b or 3 was achieved in 92.8% (95% CI, 91.6, 93.9) of procedures, with 55.3% (95% CI, 53.1, 57.5) of patients achieving modified Rankin Scale ≤2 at 3 months. Patients meeting revised 2015 American Heart Association criteria for thrombectomy had a 59.7% (95% CI , 56.0; 63.4) modified Rankin Scale 0 to 2 at 3 months, whereas 51.4% treated outside of American Heart Association criteria had modified Rankin Scale 0 to 2. 51.4% (95% CI , 49.6, 55.4). Symptomatic intracranial hemorrhage rate was 1.7% (95% CI , 1.2, 2.4). Conclusions The Trevo Retriever Registry represents real-world data with stent retriever. The registry demonstrates similar reperfusion rates and outcomes in the community compared with rigorous centrally adjudicated clinical trials. Future subgroup analysis of this cohort will assist in identifying areas of future research. Clinical Trial Registration URL : https://www.clinicaltrials.gov . Unique identifier: NCT 02040259.

Innovations in Care Delivery of Stroke from Emergency Medical Services to the Neurointerventional Operating Room

Acute ischemic stroke (AIS) and its care is currently one of the most dynamic and evolving illnesses across the globe. Among the most crucial factors in providing the best care to patients are the expedient delivery of thrombolytics and endovascular intervention when indicated. Here, we review our unique model of efficient care centered in our innovative Neurological Emergency Department (Neuro ED). The Neuro ED acts as our hub for EMS communication, imaging, administration of intravenous alteplase, and transition to the Neurointerventional OR. Our structure with its enabling of shortened IV alteplase delivery times and faster door-to-needle (DTN) times may serve as an international model for stroke centers.

Effect of balloon guide catheter on clinical outcomes and reperfusion in Trevo thrombectomy

Introduction

The Solitaire stent retriever registry showed improved reperfusion, faster procedure times, and better outcome in acute stroke patients with large vessel occlusion treated with a balloon guide catheter (BGC) and Solitaire stent retriever compared with a conventional guide catheter. The goal of this study was to evaluate whether use of a BGC with the Trevo stent retriever improves outcomes compared with a conventional guide catheter.

Methods

The TRACK registry recruited 23 sites to submit demographic, clinical, and site adjudicated angiographic and outcome data on consecutive patients treated with the Trevo stent retriever. BGC use was at the discretion of the physician.

Results

536 anterior circulation patients (of whom 279 (52.1%) had BGC placement) were included in this analysis. Baseline characteristics were notable for younger patients in the BGC group (65.4±15.3 vs 68.1±13.6, P=0.03) and lower rate of hypertension (72% vs 79%, P=0.06). Mean time from symptom onset to groin puncture was longer in the BGC group (357 vs 319 min, P=0.06).Thrombolysis in Cerebral Infarction 2b/3 scores were higher in the BGC cohort (84% vs 75.5%, P=0.01). There was no difference in reperfusion time, first pass effect, number of passes, or rescue therapy. Good clinical outcome at 3 months was superior in patients with BGC (57% vs 40%; P=0.0004) with a lower mortality rate (13% vs 23%, P=0.008). Multivariate analysis demonstrated that BGC use was an independent predictor of good clinical outcome (OR 2; 95% CI 1.3 to 3.1, P=0.001).

Conclusions

In acute stroke patients presenting with anterior circulation large vessel occlusion, use of a BGC with the Trevo stent retriever resulted in improved reperfusion, improved clinical outcome, and lower mortality.

Abstract WP37: Real-World Applicability of Thrombectomy in Anterior Circulation Large Vessel Occlusion Strokes Treated in the Extended Window: Analysis of the Prospective Trevo Registry

Background: Two recent trials showed a strong benefit of thrombectomy in the extended window. However, these studies were performed in selected centers and utilized strict inclusion criteria. We aim to evaluate the outcomes of thrombectomy in a large prospective cohort treated outside the rigid clinical trial setting.

Methods: Trevo Registry patients with ICA, MCA-M1 or M2 occlusions and pre-morbid mRS0-2 were categorized according to time-from-last-seen-well (TLSW) to puncture as early (0-6hours) vs. late (6-24hours). Uni- and multivariate analyzes were performed to identify good outcome (90-day mRS0-2) predictors. Subgroup analyses were performed for the basic DAWN (age >=18, NIHSS >=10, ICA or M1 occlusion, pre-morbid mRS 0-1) and DEFUSE 3 (age 18-90, NIHSS >=6, ICA or MCA-M1 occlusion, mRS 0-2) trial criteria.

Results: As compared to the late (n=430), early patients (n=1173) were older (70 vs 68, p=0.011) and had higher IV tPA use (69 vs 25%, p<0.001), lower smoking frequency (33 vs 40%, p=0.011), larger baseline infarcts (21.2 vs 15.6 cc, p=0.045), less frequent ICA occlusions (18 vs 24%, p=0.015), and a trend towards higher admission NIHSS (16 vs 15, p=0.09). Despite significantly longer TLSW to puncture (3.5 vs 9.6 h, p<0.001), late patients had similar rates of mTICI2b-3 (92 vs 94%, p=0.20), good outcomes (60 vs 56%, p=0.128), symptomatic ICH (1.5 vs.1.4%, p=0.84), and 90-day-mortality (10.9 vs.11.4%, p=0.79). Age (OR 0.96, 95%CI [0.96-0.97]), admission-NIHSS (0.91 [0.89-0.93]), baseline mRS (0.49 [0.40-0.60]), ASPECTS >= 6 (1.37 [1.07-1.75]), DM (0.58 [0.44-0.77]), and time to treatment (0.98 [0.97-1.00]) were independent predictors of good outcomes. Imaging modality did not predict outcomes. Similar findings were observed in the early versus late DAWN-like (n=709 vs 257) and DEFUSE 3-like (n=855 vs 273) cohorts. There was great similarity between the outcomes of the Trevo Registry subsets vs their analogous RCTs: early DAWN-like vs SWIFT Prime (90-day mRS 0-2: 57.5 vs 60%; 90-day mRS 6: 11.% vs 9%), Late DAWN-like vs DAWN (50.2 vs 48.6%; 10.6 vs 18%), and Late DEFUSE 3-like vs DEFUSE 3 (52 vs 45%; 10.3 vs 14%).

Conclusions: Our study provides favorable data for the generalizability of the safety and efficacy of thrombectomy in the “real-world” setting.

Abstract WP111: Who Needs Neuroprotection With Endovascular Stroke Therapy? Findings From the Trevo Retriever Registry

Background: Combined neuroprotection with endovascular therapy may improve clinical outcomes of only a subset of individuals treated for acute ischemic stroke. The risk/benefit profile of adjunctive treatment may not warrant neuroprotection with successful reperfusion, yet many other individuals have poor outcomes despite revascularization. We hypothesized that optimal candidates for adjunctive neuroprotection may be defined by analyses of subjects with poor clinical outcome despite successful reperfusion in the Trevo Retriever Registry.

Methods: The Trevo Retriever Registry dataset was analyzed to define the subset of cases with poor clinical outcome (day 90 mRS 4-6) after successful reperfusion (eTICI 2b50, 2b67, 2c, 3). Multivariate analyses were used to identify predictors of poor outcome using these distinct definitions of successful reperfusion. The influence of covariates, including TLSW, baseline clinical and imaging variables (e.g. ASPECTS, ASITN collateral grade), on defining such optimal neuroprotective candidates was delineated.

Results: Successful reperfusion adjudicated by core lab, defined as eTICI ≥ 2b50 included 1,162 subjects, with eTICI ≥ 2b67 in 920, eTICI ≥ 2c in 652 and eTICI 3 in 209. Poor outcome (day 90 mRS 4-6) occurred in 316/1162 (27%) with eTICI ≥ 2b50, 243/920 (26%) with eTICI ≥ 2b67, 172/652 (26%) with eTICI ≥ 2c and 61/209 (29%) with eTICI 3. Across all subsets, multivariate analyses to predict poor outcome after successful reperfusion identified increased age (per year, OR 1.04-1.05, all p=<0.02) as a factor, adjusting for withdrawal of care. Expectedly, greater baseline NIHSS severity predicted greater day 90 disability (OR 1.07-1.08, all p<0.001). TLSW was a predictor only with eTICI ≥ 2b50 (per hour, OR 1.02, p=0.039). History of diabetes was a factor only with eTICI ≥ 2b50 and eTICI ≥ 2b67 (OR 2.05-2.19, p<0.001). Worse collateral grade (ASITN 0-1) was the most potent predictor (OR 2.27-2.71 versus ASITN 2, p=0.027-0.052; OR 3.85-4.35 versus ASITN 3-4, all p=0.003).

Conclusions: Neuroprotection combined with endovascular therapy may optimally target stroke patients with worse collaterals, diabetes or increased age. Trial design for neuroprotection with revascularization in AIS should leverage these data.

Abstract WMP4: Fast versus Slow Progressors in Real-World Data From the Trevo Retriever Registry: Collaterals Dominate Time to Reperfusion in Clinical Outcome After Thrombectomy

Background: Time to reperfusion (TTR) is commonly cited in clinical outcome after endovascular treatment of acute ischemic stroke, yet collaterals may set the pace of ischemia. Real-world data on fast and slow progressors also remain scarce. We analyzed the impact of TTR on clinical outcome in real-world data using core lab adjudicated angiography, interventional steps and corresponding reperfusion.

Methods: 16 key time intervals were calculated from workflow (time of symptom onset, door, picture, puncture) and core lab metrics (clot visualization, first deployment, first reperfusion, final angiography) in real-world data from the Trevo Retriever Registry. These 16 variations of TTR were analyzed overall and by collateral status (ASITN 0-1 versus 2 versus 3-4) to determine the relationship with 90-day clinical outcomes.

Results: Real-world data on endovascular therapy from 1,441 subjects in the Trevo Retriever Registry were analyzed to relate TTR with clinical outcomes. Overall metrics for TTR are shown in Table 1. TTR was not linked with collateral status. Using a multivariate model incorporating known predictors, there was no influence of TTR using any of the 16 definitions on clinical outcome. Better collateral status on DSA prior to revascularization showed a potent relationship with 90-day mRS (p<0.001) and better probability of functional independence (aOR 1.4, 95% CI 1.2, 1.7) per grade of collateral flow.

Conclusions: Collaterals transform time to reperfusion, linking fast and slow progressors with subsequent clinical outcomes. TTR may be standardized based on these 16 key epochs in endovascular stroke therapy to document workflow metrics. Time is relative, even when measured with detailed, standardized metrics.

Abstract WMP6: Predictors of Times to Reperfusion in the TRACK Trevo Stent-retriever Registry

Background: Time to mechanical thrombectomy is a significant driver of outcomes in acute ischemic stroke (AIS) patients presenting with large vessel occlusion (LVO). We aimed to evaluate predictors of onset to groin puncture (OTG), groin puncture to reperfusion (GTR), and onset to reperfusion (OTR) times in AIS patients treated with the Trevo stent-retriever.

Methods: The investigator-initiated TRACK registry recruited 23 clinical sites to submit demographic, clinical, site-adjudicated angiographic, and outcome data on consecutive patients treated with the Trevo device. We included patients treated <8 hours from last known normal (LKN). Times for LKN, groin puncture, and TICI 2b/3 reperfusion were available to calculate OTG, GTR, and OTR times. Using multivariable linear regression, we evaluated potential predictors of times including demographics, risk factors, baseline NIHSS score, intravenous tPA use, inter-facility transfer, perfusion imaging selection, type of anesthesia, location of LVO, use of rescue intra-arterial therapies, and number of passes.

Results: Among 433 patients analyzed (mean age 66.8 +/- 14.6 years; median NIHSS score 18; 88% anterior circulation), the median times were: OTG 240, GTR 64, and OTR 321 minutes. In multivariable analysis (Table), the independent predictors were: 1) OTG: transfer status and general anesthesia (GA) use; 2) GTR: 1 pass attempt only, use of rescue therapy, GA use, and baseline mRS >1; and 3) OTR: transfer status, use of perfusion imaging, anterior circulation LVO, use of rescue therapy, and 1 pass attempt only.

Conclusions: Major pre-treatment contributors to delays to reperfusion in AIS patients treated <8 hours in the TRACK registry included inter-facility transfer (+82.5 minutes) and use of perfusion imaging (+30.6 minutes). Reducing inter-facility transfer delays, direct transport to thrombectomy-capable hospitals, and minimizing perfusion imaging would have major impact on reducing treatment times.

Abstract 109: Trevo 2000: Results of the Largest Real-World Registry for Stent Retriever for Acute Ischemic Stroke

Objective: The Trevo Registry was designed to assess real world outcomes of the Trevo Retriever in patients experiencing ischemic stroke. It is the largest prospective study for acute stroke intervention, with 2010 patients enrolled and 90 day outcomes in 1873 patients. The primary endpoint is revascularization status based on post-procedure TICI score and secondary endpoints include 90-day mRS, 90-day mortality, neurological deterioration at 24 hours and device/procedure related adverse events.

Methods: The study was a prospective, open-label, consecutive enrollment, multi-center, international registry of patients who underwent mechanical thrombectomy for acute stroke using the Trevo stent retriever as the initial device.

Results: The median NIHSS at admission was 16 (IQR 11-20). Most patients (70.8%) were treated at <= 6 hours from last known normal with a median procedure time of 50 minutes (32-77). The occlusion site was M1 or M2 in 73.9%. General anesthesia was employed in 43.5% of procedures. TICI 2b or 3 revascularization was 92.8% with an average of 1.7 passes with the device. Median NIHSS at 24 hours and discharge was 6 and 4 respectively. Fifty-five percent (55.2%) of patients had mRS ≤2 at 3 months and the overall mortality rate was 13.8%. Patients treated after 8 hours of symptom onset had a 95% revascularization rate and 51.2% mRS ≤2 at 3 months. The symptomatic ICH rate was 1.6%. Patients who met the revised AHA criteria for thrombectomy were found to have 59.5% mRS 0-2 at 90 days.

Conclusions: The Trevo Retriever Registry represents the first real world data with stent retriever use in the era of clinical trials showing the overwhelming benefit of stent retrievers to treat acute ischemic stroke. Due to the fact that this data represents real world use of the Trevo Retriever, (e.g. subjects pre-stroke mRS >1 (29%) and those treated 6-24 hours after stroke symptoms (29%), this data cannot be compared to the results from recent trials with restricted eligibility criteria. Future subgroup analysis of this large cohort will help to identify areas of future research to enhance outcomes further with this treatment modality.

Abstract 63: Collaterals in Thrombectomy for MCA Occlusion: Mapping the Collaterome in the Trevo Retriever Registry

Background: The delay and dispersion of collateral circulation to the MCA territory is readily available prior to endovascular thrombectomy for acute ischemic stroke (AIS). Factors associated with collateral grade have never been established in such an extensive population, reflecting diverse subjects from around the world. Largescale data from the Trevo Retriever Registry enables mapping of the MCA collaterome for the first time.

Methods: The Imaging and Angiography Core Lab of the Trevo Retriever Registry independently conducted prospective evaluation of angiography in more than 1,500 subjects. Collaterals were systematically scored using ASITN grade prior to thrombectomy. Descriptive statistics detailed the distribution of collateral grades and analyses with demographic, imaging and clinical variables to explore key associations with routinely acquired registry data.

Results: 890 subjects (68.5 ± 15.1 years; 54.6% women; baseline NIHSS median 15 (10-19)) with AIS due to MCA occlusion had angiography of collateral circulation centrally adjudicated. Proximal M1 MCA occlusion was noted in 671/890 (75.4%). Collateral grade prior to thrombectomy included grade 4 or most robust collaterals in 38/890 (4.3%), 3 in 294/890 (33.0%), 2 in 467/890 (52.5%), 1 in 80/890 (9%) and 0 or none in 11/890 (1.2%). Baseline collaterals at angiography and pre-procedure ASPECTS were closely correlated (r=0.439, p<0.001) with more modest correlation between collateral grade and CTP/DWI (rrCBF<30% or ADC<620) infarct core (r=-0.31, n=391; p<0.001) or CTP/PWI (Tmax>6s) hypoperfusion at-risk (r=-0.10, n=391; p=0.043) volumes. First pass mTICI≥2b occurred in 553/858 (64.5%) with final mTICI≥2b in 824/890 (92.6%). Collateral grade prior to thrombectomy (each 1-point increment, after adjustment for other predictors) was strongly associated (OR 1.38 95%CI (1.12-1.7), p=0.002) with good clinical outcomes (mRS 0-2) at 90 days.

Conclusions: Largescale mapping of collaterals prior to MCA thrombectomy reveals marked variation in the extent and functional impact of the collaterome. The preponderance of partial perfusion in the downstream ischemic territory prompts the need to investigate and leverage the protective nature of the collaterome in AIS.

Abstract WP8: Global Real World Evidence of Balloon Guided Stent Retriever Thrombectomy

Background and Aims: Balloon Guide Catheter (BGC) use during thrombectomy treatment in Stroke patients has been reported to have positive effects on revascularization, procedural characteristics, and clinical outcomes. We evaluate the use of BGC in an open-label large prospective TREVO Retriever Registry of real world patients to determine predictors of good ‘clinical’ outcomes.

Method: Consecutive Trevo Registry patients that had Balloon Guide Catheter (BGC) used during their thrombectomy procedure were identified; a subset of patients who fulfilled the criteria (ICA and/or MCA-M1/M2 occlusion with pre-morbid mRS 0-1, TLSW ≤6 hrs) within the cohort were also identified. Multivariate analysis was performed to identify the predictors of good outcomes in BGC thrombectomy patients.

Results: A total of 1031 BGC treated Trevo Registry patients (overall enrolled, n=2010) qualified for analysis, of which 605 patients fulfilling the subset criteria were identified. The mean age of BGC/stent retriever patients was 67.5 with a median (IQR) baseline NIHSS of 15(11-19). Occlusion location of the BCG group was ICA -20.4%, M1- 57.1%, M2/M3-20.3%, and Posterior 1.8%.

In the overall BGC cohort, the median (IQR) time to treatment was (4.2 (3.0,6.5)- hrs.) with conscious/local sedation used in 63.4% and general anesthesia used in 37.3% of cases. The median number of passes with Trevo stent retriever was 1 and revascularization (mTICI ≥ b) was achieved in 92.8% of cases. The sICH rate was low at 1.9% (20/1031) with a low rate of vessel perforation (0.2%). At 90 days post stroke, 56.0% of patients achieved functional independence (mRS 0-2) with 63.7% of the subset of “guidline “ BGC patients achieving functional independence at 90 days. Multivariate logistic regression showed age (aOR 0.97 [0.96, 0.99] P <0.001), Diabetes (aOR 0.67, [0.18,0.98] P =0.03), conscious sedation vs general anesthesia ( aOR 1.7 [1.2,2.3], P= 0.002, number of passes (aOR 0.76 [0.66-0.88],P <0.001), pre stroke mRS (aOR 0.54 [0.45-0.65], P <0.0010 and NIHSS (aOR 0.93 [0.91-0.95], P <0.001) as predictors of functional independence .

Conclusion: Data from Trevo Registry demonstrate the use of BGC in thrombectomy procedure is safe, and leads to a reduction of disability in ischemic stroke patients.

Abstract 112: Identifying Patients Who May Benefit From Thrombectomy in the Late Time Window: Predictors of Good Outcome Beyond Advanced Imaging

Background: The DAWN trial showed EVT effectiveness in the late time window (6-24 hrs), however, DAWN patients were carefully selected based on advanced perfusion imaging, CTP and MRI. Similar to the early window (0-6 hrs), simple imaging (CT) and other clinical variables may select patients for thrombectomy beyond 6 hours. We evaluated a largescale, real world practice for predictors that could identify patients who may benefit from EVT in the late time window.

Methods: Patients with LVO in the anterior circulation (M1, M2, ICA) from a prospective, single arm, multicenter, international registry (Trevo Retriever Registry) treated in the late window LSN to groin puncture (GP) (6-24 hrs) were included. Univariate and multivariate analyses assessed factors independently correlating with good outcome (90 day mRS 0-2). Furthermore, patients outcomes were compared based on their baseline imaging selection CT vs CTP and MRI.

Results: 549 patients were treated beyond 6 hours. The average age was 67, median/IQR ASPECTS 8(6-9), median/IQR NIHSS was 15 (9-20), median/IQR time LSN to GP (hr) was 9.7 (7.3-13.6) and IV-tPA rate were 22.8%. CT was the only imaging selection method in 15.9%, while additional advanced imaging was utilized in the remaining patients; CTP (70%), and MRI(14.1%). Good outcomes were observed in 51.4% of late window patients. Age (aOR 0.96, 95% CI 0.94-0.98, p<0.001), stroke severity by NIHSS (aOR 0.9, 95% CI 0.86-0.95, p<0.001) and ASPECTS (for each point increment in ASPECTS aOR 1.24, 95% CI 1.05-1.47, p=0.012) were independent pre-intervention predictors of good outcome in the late window. The addition of advanced imaging beyond CT, including CTP or MRI, did not confer higher correlation with good outcome (aOR 1.45, 95% CI 0.77-2.73, p=0.25). Good outcome was achieved in 56% of CT selected patients as compared to 53% patients selected by CTP or MRI.

Conclusion: Simple imaging and clinical variables can identify patients that could benefit from thrombectomy in the late window. Importantly, ASPECTS reliably predicted good outcome beyond 6 hours without adjunctive benefit from adding advanced perfusion imaging, a finding that may simplify patients selection to facilitate and generalize the intervention in the late window to wide, real world practice.

Abstract TP29: Endovascular Therapy for Distal Occlusions in the Early and Late Window: an Extension in Location and Time

Background: Endovascular therapy (EVT) effectiveness is established in ischemic strokes with large vessel occlusion (LVO) in the terminal ICA and M1, which was extended up to 24 hrs by recent DAWN trial results. However this benefit is not as well established in more distal (M2) occlusions, especially late presenters (beyond 6 hrs). We evaluated thrombectomy outcomes in M2 occlusions as compared to ICA/M1 across early and late time windows.

Methods: In a prospective, multicenter, single arm, international registry (Trevo Retriever Registry), anterior circulation LVOs were stratified on clot location into M2 vs ICA/M1 and dichotimized into early vs late (0-6 vs 6-24 hrs). 90 day mRS (0-1 excellent, 0-2 good) were the primary outcomes; sICH and dissection were the secondary (safety) outcomes. Multivariate analyses identified pre-procedure variables independently correlating with good outcome in M2s.

Results: 1581 patients were identified (1265 ICA/M1, 316 M2). The M2 and ICA/M1 groups were similar (age in both 68.4), IV-tPA (69.1 vs 69.7%, p=0.8) and same median/IQR ASPECTS 8 (7-9). M2 patients had lower NIHSS (13 vs 16, p<0.001). Higher good and excellent outcomes were observed in M2s (65.8% and 51.3%) compared to ICA/M1 (57.9% and 42.8%) (p=0.01). Similar outcomes were maintained beyond 6 hrs (64.8% good, 45.9% excellent in M2s vs 53.8% and 38.4% in ICA/M1) (p=0.08). Fig 1 shows the probabilities of good outcome in M2 vs ICA/M1 in relation to time, illustrating no association with time (p=0.4). Similar safety profiles were seen: sICH (0% M2 vs 0.7% ICA/M1, p=1.0) and dissections (0.3% M2 vs 0.4% ICA/M1, p=0.22). Age (aOR 0.96, 0.94-0.98 95% CI, p<0.001) and NIHSS (aOR 0.94, 0.9-0.98 95% CI, p<0.001) correlated with good outcome in M2, while IV-tPA did not have adjunctive benefit (aOR 0.72, 0.42-1.24 95% CI, p=0.24).

Conclusion: Excellent and good outcomes may be achieved in distal LVO isolated to M2 similar to those with proximal occlusions. A benefit that can be reached up to 24 hrs.

Abstract WP34: Endovascular Treatment in Large Core Strokes

Introduction: The recent thrombectomy trials were largely limited to patients with small strokes on presentation.

Methods: Patients derived from a large prospective multinational stent-retriever registry (Trevo Registry, n=2,010). Baseline NCCT SPECTS and CTP Core Volumes (rCBF<30%) were adjudicated by a Core Lab. Baseline and outcome variables were compared for ASPECTS 0-5 vs. 6-10 on NCCT and large age-adjusted cores (>70mL if age <=70 years; >50mL if age >70-80 years; >30mL if age >80 years) vs. not on CTP. The primary and secondary efficacy endpoint were the rates of 90-day mRS 0-2 and mTICI 2b-3, respectively. Safety endpoints included sICH and 90-day mortality.

Results: As compared with patients with higher baseline ASPECTS (n=1037), low baseline ASPECTS (0-4, n=78; 5, n=78) patients were younger, had higher stroke severity, and tend to have less comorbidities and undergo thrombectomy at later times (Table 1a). TICI-3 reperfusion was higher in the higher-ASPECTS group but other reperfusion outcomes were nearly the same. Safety outcomes were comparable. Rates of 90-day mRS 0-2 were significantly higher in the high-ASPECTS group (p<0.001); however, 41.8% of ASPECTS 0-5 patients were independent at 90 days and safety outcomes were similar (Table 1b). Analysis according to large age-adjusted core (n=86) vs not (n=431) yielded similarly encouraging results (Table 2a-b).

Conclusion: Patients with large baseline cores as measured by either NCCT or CTP may still achieve favorable outcomes with endovascular treatment. A randomized clinical trial in this patient population is warranted.

Abstract 114: Aspects versus Perfusion in the Trevo Retriever Registry: Defining the Core on the Largest Scale to Date

Background: Routine use of advanced imaging versus ASPECTS for imaging triage of endovascular thrombectomy candidates has not been evaluated on a large scale to date. Ischemic core may be defined by ASPECTS or perfusion imaging, yet these variable definitions likely reflect different pathophysiology as perfusion may fluctuate and ASPECTS lesions may be time-dependent.

Methods: The Trevo Retriever Registry was a prospective, open-label, consecutive enrollment, multicenter, international registry with more than 65 enrolling sites worldwide. The Imaging and Angiography Core Lab systematically adjudicated more than 1,500 subjects, scoring ASPECTS and separately processing perfusion imaging. Ischemic core volume on perfusion imaging was defined as rrCBF<30% (CTP) and analyzed with respect to ASPECTS.

Results: 488 subjects (68.3±14.4 years; 53.3% women; baseline NIHSS median 15 (10-19) with anterior circulation occlusions were evaluated with both ASPECTS and perfusion imaging prior to thrombectomy. Arterial occlusions included 87/487 (17.9%) ICA and 296/487 (60.8%) proximal M1 MCA, treated with thrombectomy at median 4.7 (3.3-7.9) hours from time last known well (TLKW). ASPECTS was median 8 (7-9) with ischemic core lesions of median 18 (4.9-39.2) cc. At-risk hypoperfusion (Tmax>6s) lesions were median 109.8 (62-156.9) cc. TLKW was associated with ASPECTS (r=-0.18, p<0.001) yet no time relationship was noted with either ischemic core or at-risk hypoperfusion on perfusion imaging. ASPECTS correlated modestly with perfusion imaging-derived ischemic core (r=-0.35, p<0.001) and at-risk hypoperfusion (r=-0.24, p<0.001). Post-procedure mTICI≥2b occurred in 448/488 (91.8%). Each increment in baseline ASPECTS was associated with an adjusted OR of 1.21 (95%CI (1.05-1.39), p<0.008 for good clinical outcomes (day 90 mRS 0-2), whereas the perfusion lesion volume for ischemic core and at-risk hypoperfusion did not predict outcomes.

Conclusions: Largescale, systematic evaluation of ASPECTS and perfusion imaging prior to thrombectomy reveals discrepancy in the definition of ischemic core and the prediction of clinical outcomes after revascularization. ASPECTS is time-dependent, yet reliably predicts outcomes in routine clinical practice.

Abstract 107: Real World Clinical and Radiographic Outcomes With and Without Intravenous tPA in Anterior Circulation Large Vessel Occlusion Mechanical Thrombectomy Patients Treated Within 8 Hours

Background and Aims: Intravenous tPA remains the standard of care, with MT currently indicated within 8 hours for IV tPA failures or patients with IV tPA contraindications. Whether LVO patients should receive IV tPA treatment or instead be triaged directly to MT therapy is currently unknown but greatly debated. The Trevo Registry is a real world, multi-center, international study of mechanical thrombectomy (MT) patients treated from 0-24 hours. Evaluation of the Trevo Registry clinical and procedurals outcomes of MT patients treated with or without IV tPA could provide insight into the benefit of IV tPA in MT patients. We hypothesized that in MT patients treated within 8 hours, pretreatment with intravenous tPA would lead to better clinical outcomes compared to patients who did not receive IV tPA.

Method: Consecutively enrolled patients treated within 8 hours with ICA, M1, or M2 occlusions were selected for analysis. Univariate and multivariable regressions were conducted to identify clinical and radiographic independent variables that correlate best with the dependent variable of functional outcome: mRS 0-2, with a focus on intravenous tPA treatment.

Results: A total of 1183 Trevo Registry patients (overall enrolled, n=2010) qualified for analysis, of whom 380 were not treated with IV tPA. Demographics were similar, however atrial fibrillation (46.3% vs 27.2%) and previous ischemic stroke (14.1% vs 7.5%) were higher in the no IV tPA group. The median time to treatment was similar (3.8 vs. 3.6 hrs). First pass mTICI ≥ 2B (63.6% vs 66.4%) and final revascularization (91.1% vs 92.8%) were similar between no IV tPA and IV tPA groups.Unadjusted, there were similar rates of functional outcome (90 day mRS 0-2; 60.9% vs. 62.5%). After adjustment, patients who did not receive IV-tPA had similar rates of good outcome (aOR 1.08, 95% CI [0.87-1.34]. P=0.58) as well as reduction (shift) in disability (aOR 1.08, 95% CI [0.87-1.34]. P=0.49). Safety outcomes (mortality, sICH) were similar between both groups.

Conclusion: In the Trevo Registry of MT patients treated within 8 hours, patients who did not receive IV tPA had similar endovascular and clinical outcomes as patients pretreated with IV tPA. The added benefit of IV tPA for MT patients should be further investigated.

Abstract TP26: Endovascular Therapy in Patients With Low NIHSS Score on Presentation

Introduction: Approximately 2/3 of all AIS present with NIHSS 0-5. While it has been demonstrated that LVO can be found in ~10-20% of all low NIHSS patients, outcome data in this population remains scarce. Indeed, only 14/1766 patients in the recent endovascular RCTs had baseline (b) NIHSS in the 0-5 range. Yet, the presence of LVO in the setting of low NIHSS is associated with ~10-fold increase in subsequent deterioration. We aim to describe the outcomes in a large cohort of low NIHSS patients undergoing thrombectomy.

Methods: Patients derived from a large prospective multicenter international stent-retriever registry (Trevo Registry, n=2,010). Baseline and outcome variables were compared according to bNIHSS 0-8 vs >8 and bNIHSS 0-5 vs >5. The primary and secondary efficacy endpoints were the rates of 90-day mRS 0-2 and mTICI 2b-3, respectively. Safety endpoints included sICH and 90-day mortality.

Results: A total of 1,985 patients were included. As compared with patients with higher baseline NIHSS, low baseline NIHSS (0-8, n=342; 0-5, n=160) patients were younger, had less comorbidities and better functional status, more frequently had MCA-M2 or vertebrobasilar occlusions, less frequently received IV tpa, and underwent thrombectomy at later times (Table 1). The reperfusion outcomes were nearly the same. There were no significant differences in procedure-related complications, which were overall low (Table 2). The rates of 90-day mRS 0-2 were significantly higher in the lower NIHSS patients (p<0.001); however, ~20% of those patients were not independent and ~7% were dead at 90 days despite presenting with low clinical severity.

Conclusion: Despite safe and efficacious endovascular reperfusion, low-NIHSS LVO patients have a relatively high proportion of bad outcomes. This supports the notion that many of "mildly" presenting patients do not fare well. A randomized clinical trial including immediate endovascular treatment in this patient population is warranted.

Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct

BACKGROUND

The effect of endovascular thrombectomy that is performed more than 6 hours after the onset of ischemic stroke is uncertain. Patients with a clinical deficit that is disproportionately severe relative to the infarct volume may benefit from late thrombectomy.

METHODS

We enrolled patients with occlusion of the intracranial internal carotid artery or proximal middle cerebral artery who had last been known to be well 6 to 24 hours earlier and who had a mismatch between the severity of the clinical deficit and the infarct volume, with mismatch criteria defined according to age (<80 years or ≥80 years). Patients were randomly assigned to thrombectomy plus standard care (the thrombectomy group) or to standard care alone (the control group). The coprimary end points were the mean score for disability on the utility-weighted modified Rankin scale (which ranges from 0 [death] to 10 [no symptoms or disability]) and the rate of functional independence (a score of 0, 1, or 2 on the modified Rankin scale, which ranges from 0 to 6, with higher scores indicating more severe disability) at 90 days.

RESULTS

A total of 206 patients were enrolled; 107 were assigned to the thrombectomy group and 99 to the control group. At 31 months, enrollment in the trial was stopped because of the results of a prespecified interim analysis. The mean score on the utility-weighted modified Rankin scale at 90 days was 5.5 in the thrombectomy group as compared with 3.4 in the control group (adjusted difference [Bayesian analysis], 2.0 points; 95% credible interval, 1.1 to 3.0; posterior probability of superiority, >0.999), and the rate of functional independence at 90 days was 49% in the thrombectomy group as compared with 13% in the control group (adjusted difference, 33 percentage points; 95% credible interval, 24 to 44; posterior probability of superiority, >0.999). The rate of symptomatic intracranial hemorrhage did not differ significantly between the two groups (6% in the thrombectomy group and 3% in the control group, P=0.50), nor did 90-day mortality (19% and 18%, respectively; P=1.00).

CONCLUSIONS

Among patients with acute stroke who had last been known to be well 6 to 24 hours earlier and who had a mismatch between clinical deficit and infarct, outcomes for disability at 90 days were better with thrombectomy plus standard care than with standard care alone. (Funded by Stryker Neurovascular; DAWN ClinicalTrials.gov number, NCT02142283 .).

TREVO stent-retriever mechanical thrombectomy for acute ischemic stroke secondary to large vessel occlusion registry

Background

Recent randomized clinical trials (RCTs) demonstrated the efficacy of mechanical thrombectomy using stent-retrievers in patients with acute ischemic stroke (AIS) with large vessel occlusions; however, it remains unclear if these results translate to a real-world setting. The TREVO Stent-Retriever Acute Stroke (TRACK) multicenter Registry aimed to evaluate the use of the Trevo device in everyday clinical practice.

Methods

Twenty-three centers enrolled consecutive AIS patients treated from March 2013 through August 2015 with the Trevo device. The primary outcome was defined as achieving a Thrombolysis in Cerebral Infarction (TICI) score of ≥2b. Secondary outcomes included 90-day modified Rankin Scale (mRS), mortality, and symptomatic intracranial hemorrhage (sICH).

Results

A total of 634patients were included. Mean age was 66.1±14.8 years and mean baseline NIH Stroke Scale (NIHSS) score was 17.4±6.7; 86.7% had an anterior circulation occlusion. Mean time from symptom onset to puncture and time to revascularization were 363.1±264.5 min and 78.8±49.6 min, respectively. 80.3% achieved TICI ≥2b. 90-day mRS ≤2 was achieved in 47.9%, compared with 51.4% when restricting the analysis to the anterior circulation and within 6 hours (similar to recent AHA/ASA guidelines), and 54.3% for those who achieved complete revascularization. The 90-day mortality rate was 19.8%. Independent predictors of clinical outcome included age, baseline NIHSS, use of balloon guide catheter, revascularization, and sICH.

Conclusion

The TRACK Registry results demonstrate the generalizability of the recent thrombectomy RCTs in real-world clinical practice. No differences in clinical and angiographic outcomes were shown between patients treated within the AHA/ASA guidelines and those treated outside the recommendations.

Training Standards in Neuroendovascular Surgery: Program Accreditation and Practitioner Certification

BACKGROUND AND PURPOSE

Neuroendovascular surgery is a medical subspecialty that uses minimally invasive catheter-based technology and radiological imaging to diagnose and treat diseases of the central nervous system, head, neck, spine, and their vasculature. To perform these procedures, the practitioner needs an extensive knowledge of the anatomy of the nervous system, vasculature, and pathological conditions that affect their physiology. A working knowledge of radiation biology and safety is essential. Similarly, a sufficient volume of clinical and interventional experience, first as a trainee and then as a practitioner, is required so that these treatments can be delivered safely and effectively.

METHODS

This document has been prepared under the aegis of the Society of Neurological Surgeons and its Committee for Advanced Subspecialty Training in conjunction with the Joint Section of Cerebrovascular Surgery for the American Association of Neurological Surgeons and Congress of Neurological Surgeons, the Society of NeuroInterventional Surgery, and the Society of Vascular and Interventional Neurology.

RESULTS

The material herein outlines the requirements for institutional accreditation of training programs in neuroendovascular surgery, as well as those needed to obtain individual subspecialty certification, as agreed on by Committee for Advanced Subspecialty Training, the Society of Neurological Surgeons, and the aforementioned Societies. This document also clarifies the pathway to certification through an advanced practice track mechanism for those current practitioners of this subspecialty who trained before Committee for Advanced Subspecialty Training standards were formulated.

CONCLUSIONS

Representing neuroendovascular surgery physicians from neurosurgery, neuroradiology, and neurology, the above mentioned societies seek to standardize neuroendovascular surgery training to ensure the highest quality delivery of this subspecialty within the United States.

Abstract WP5: The Transfer Score May Aid Decisions Whether to Transfer Patients with Large Vessel Occlusions for Endovascular Therapy

Background: While faster reperfusion with EVT leads to better outcomes in acute ischemic stroke due to large vessel occlusion (LVO), most LVO patients present to outside hospitals without EVT capability. Treating physicians are often unsure if EVT would confer benefit upon arrival to tertiary hospitals given inter-facility transfer delays.

Objective: We evaluated independent predictors of good outcome in transferred patients treated with EVT to devise a score that may assist treating physicians to make transfer and treatment decisions.

Methods: Transfer patients were analyzed in a multicenter international prospective cohort study of LVO patients treated with stent retriever thrombectomy (TREVO Registry) from 11/2013 to 4/2016. Independent factors correlating with good outcome after EVT were identified using univariate and multivariate analyses. We devised a score to identify patients with LVO at the referral facility who may benefit from EVT.

Results: Of 1000 patients enrolled, 226 were anterior circulation occlusions, transferred and treated within 0-8 hrs (Table 1). Age, stroke severity, glucose level, M2 occlusion and achieving onset to groin puncture ≤ 5 hr were independent factors associated with good outcome (Table 2). Other clinical variables were analyzed, as in ASPECTS, but were not significant. A 10 point score was devised (Table 3). Patients with a score of 0-4 had 4 times the odds of good outcome compared to a score of 5-9 (aOR 4.3, 95% CI 1.9-9.9; p <0.001). These results were maintained after adjustment for mTICI and IV-tPA (aOR 4.0, 95% CI 1.7-9.4; p <0.001). Fig 1 shows good outcome rates stratified by score points. ROC curves showed better score performance (AUC= 0.8) compared to THRIVE (AUC=0.74) and HIAT (AUC=0.69) certifying good predictability.

Conclusion: A simple transfer score may be an effective triage method to identify patients at remote facilities who may benefit from EVT upon transfer. Further validation is necessary to confirm these findings.

Abstract WMP2: Trevo 2000: Real-World Experience in the First 1247 Patients

Objective: The Trevo Registry is designed to assess real world outcomes of the Trevo Retriever in patients experiencing ischemic stroke. This is the largest prospective study for acute stroke intervention, with 1247 patients currently enrolled and 90 day outcomes in 1021 patients. The primary endpoint is revascularization status based on post-procedure TICI score and secondary endpoints include 90-day mRS, 90-day mortality, neurological deterioration at 24 hours and device/procedure related adverse events.

Methods: The study is a prospective, open-label, consecutive enrollment, multi-center, international registry of patients undergoing mechanical thrombectomy for acute stroke using the Trevo stent retriever as the initial device. Enrollment is expected to reach 2000 subjects at up to 100 sites.

Results: As of August 13, 2016 a total of 1247 patients were enrolled. The median NIHSS at admission was 16 (IQR 11-20). Most patients (66.2%) were treated at >/= 6 hours from last known normal with a median procedure time of 50 minutes (32-77). The occlusion site was M1 or M2 in 74.5%. General anesthesia was employed in 46.6% of procedures. TICI 2b or 3 revascularization was 92.8% with an average of 1.6 passes with the device. Median NIHSS at 24 hours and discharge was 6 and 4 respectively. Fifty-five percent of patients had mRS ≤2 at 3 months and the overall mortality rate was 15.4%. Patients treated after 8 hours of symptom onset had a 94.9% revascularization rate and 52.8% mRS ≤2 at 3 months. The symptomatic ICH rate was 1.2%. Patients who met the revised AHA criteria for thrombectomy were found to have 58.4% mRS 0-2 at 90 days.

Conclusions: The Trevo Retriever Registry represents the first real world data with stent retriever use in the era of clinical trials showing the overwhelming benefit of stent retrievers to treat acute ischemic stroke. Due to the fact that this data represents real world use of the Trevo Retriever, (e.g. subjects pre-stroke mRS >1 (16.5%) and those treated 6-24 hours after stroke symptoms (33.8%), this data cannot be compared to the results from recent trials with restricted eligibility criteria. Future subgroup analysis of this large cohort will help to identify areas of future research to enhance outcomes further with this treatment modality.

Abstract WMP9: Endovascular Thrombectomy Impact in the First Three “Golden” Hours

Background: Endovascular thrombectomy (EVT) substantially increases the likelihood of good outcome in acute ischemic strokes due to large vessel occlusion (LVO). Expediting EVT to achieve faster reperfusion is an important factor that correlates with good outcome. Ultra-early intervention in the first 3 “golden” hours from onset was not well characterized in recent trials.

Objective: We sought to assess the impact of early treatment within the first 3 hours on clinical outcomes in large, real life, world-wide practice.

Methods: We analyzed a multicenter international prospective cohort study of LVO patients treated with stent retriever thrombectomy (TREVO Registry) between11/2013 and 4/2016. We stratified patients based on treatment time, onset to groin puncture (GP), into 3 groups: 0-3, 3-6, >6 hrs. 90 day mRS was the primary outcome (0-2 good outcome). Logistic regression modeling was performed to evaluate the impact of treatment within the golden 3 hours on outcomes and to determine the independent factors associated with EVT initiation within 3 hours.

Results: In the 905 patients, GP occurred in: 23.1% 0-3 hrs, 44.3% 3-6 hrs and 32.6% >6 hrs. Table 1 shows similar baseline characteristics among the groups. Patient-level predictors of treatment within 3 hrs were age (aOR 1.1 per decade of age ≥18) and good ASPECTS (aOR 1.2 per point). No hospital-level predictors of early treatment were found. Patients treated within 3 hrs have a higher likelihood of good outcome as compared to those treated >3 hrs (aOR 2.0, 95% CI 1.4-2.9; p <0.001) after adjustment for age, NIHSS, IV tPA and mTICI ≥2b (Table 2). No differences were found in mortality and sICH. Treatment in the golden hours had the highest impact on excellent outcome rates (mRS 0-1) (Fig 1).

Conclusion: Early thrombectomy of LVO strokes, within the first three hours provides the highest impact compared with later time windows. Streamlining processes to deliver rapid intervention within 3 hours would improve clinical outcomes.