Proximal Large Vessel Occlusion Research Articles

Clinical Comparison of New Generation 0.071-inch and 0.072-inch Aspiration Catheters

Three new 0.071-inch and 0.072-inch aspiration catheters have been introduced for stroke thrombectomy. Their comparative efficacy has not been clinically evaluated. We reviewed a prospectively maintained thrombectomy database for cases using 1 of these 3 catheters for proximal large vessel occlusion from September 2018 to February 2019. Clinical and angiographic information was extracted. Of 145 thrombectomies performed over the time period, 49 utilized 1 of the 3 new large-bore catheters (React 71, n= 21; Vecta 71, n= 19; Jet 7, n= 9) on the first pass. Mean patient age was 73 years (SD: 15). Mean presenting National Institute of Health Stroke Scale score was 19 (SD: 6, range: 5-33). Clot location was middle cerebral artery first segment in 59% of cases, internal carotid artery in 31%, and basilar in 10%. With or without a stentriever, clot access with the initially selected aspiration catheter was achieved in 47 of 49 (96%) cases. Excluding empiric stentriever usage, the aspiration catheter could be delivered to the clot without needing a stentriever in 87% of cases: 100% with React 71, 93% with Vecta 71, and 43% with Jet 7 (P= 0.002). Final Thrombolysis in Cerebral Infarction score 2b/3 was achieved in 92% of cases overall: 95% with React 71, 89% with Jet 7, and 89% with Vecta 71. Median procedure time was 28 minutes; mean total number of passes was 2.4 (SD: 1.6) with 39% of cases being single-pass cases. These rates did not significantly differ between aspiration catheters. In comparing the newest large bore aspiration catheters, similar angiographic efficacy is achieved.

Exploring the relationship between ischemic core volume and clinical outcomes after thrombectomy or thrombolysis.

To assess whether complete reperfusion after IV thrombolysis (IVT-R) would result in similar clinical outcomes compared to complete reperfusion after endovascular thrombectomy (EVT-R) in patients with a large vessel occlusion (LVO). EVT-R patients were matched by age, clinical severity, occlusion location, and baseline perfusion lesion volume to IVT-R patients from the International Stroke Perfusion Imaging Registry (INSPIRE). Only patients with complete reperfusion on follow-up imaging were included. The excellent clinical outcome rates at day 90 on the modified Rankin Scale (mRS) were compared between EVT-R vs IVT-R patients within quintiles of increasing baseline ischemic core and penumbral volumes. From INSPIRE, there were 141 EVT-R patients and 141 matched controls (IVT-R) who met the eligibility criteria. In patients with a baseline core <30 mL, EVT-R resulted in a lower odds of achieving an excellent outcome at day 90 compared to IVT-R (day 90 mRS 0-1 odds ratio 0.01, p < 0.001). The group with a baseline core <30 mL contained mostly patients with distal M1 or M2 occlusions, and good collaterals (p = 0.01). In patients with a baseline ischemic core volume >30 mL (internal carotid artery and mostly proximal M1 occlusions), EVT-R increased the odds of patients achieving an excellent clinical outcome (day 90 mRS 0-1 odds ratio 1.61, p < 0.001) and there was increased symptomatic intracranial hemorrhage in the IVT-R group with core >30 mL (20% vs 3% in EVT-R, p = 0.008). From this observational cohort, LVO patients with larger baseline ischemic cores and proximal LVO, with poorer collaterals, clearly benefited from EVT-R compared to IVT-R alone. However, for distal LVO patients, with smaller ischemic cores and better collaterals, EVT-R was associated with a lower odds of favorable outcome compared to IVT-R alone.

‘Real-world’ comparison of first-line direct aspiration and stent retriever mechanical thrombectomy for the treatment of acute ischemic stroke in the anterior circulation: a multicenter international retrospective study

BackgroundThrombectomy for anterior large vessel occlusion less than 24 hours since last known well is now standard of care. Certain aspects of clinical trials may limit generalizability to ’real-world' practice.ObjectiveTo...

Cardiac Biomarkers Predict Large Vessel Occlusion in Patients with Ischemic Stroke

Background and PurposeCardiac biomarkers may help identify stroke mechanisms and may aid in improving stroke prevention strategies. There is limited data on the association between these biomarkers and acute ischemic stroke (AIS) caused by large vessel occlusion (LVO). We hypothesized that cardiac biomarkers (cardiac troponin and left atrial diameter [LAD]) would be associated with the presence of LVO. MethodsData were abstracted from a single center prospective AIS database over 18 months and included all patients with AIS with CT angiography of the head and neck. The presence of LVO was defined as proximal LVO of the internal carotid artery terminus, middle cerebral artery (M1 or proximal M2), or basilar artery. Univariate analyses and predefined multivariable models were performed to determine the association between cardiac biomarkers (positive troponin [troponin ≥0.1 ng/mL] and LAD on transthoracic echocardiogram) and LVO adjusting for demographic factors (age and sex), risk factors (hypertension, diabetes, hyperlipidemia, history of stroke, congestive heart failure, coronary heart disease, and smoking), and atrial fibrillation (AF). ResultsWe identified 1234 patients admitted with AIS; 886 patients (71.8%) had vascular imaging to detect LVO. Of those with imaging available, 374 patients (42.2%) had LVO and 207 patients (23.4%) underwent thrombectomy. There was an association between positive troponin and LVO after adjusting for age, sex and other risk factors (adjusted OR 1.69 [1.08-2.63], P = .022) and this association persisted after including AF in the model (adjusted OR 1.60 [1.02-2.53], P = 0.043). There was an association between LAD and LVO after adjusting for age, sex, and risk factors (adjusted OR per mm 1.03 [1.01-1.05], P = 0.013) but this association was not present when AF was added to the model (adjusted OR 1.01 [0.99-1.04], P = .346). Sensitivity analyses using thrombectomy as an outcome yielded similar findings. ConclusionsCardiac biomarkers, particularly serum troponin levels, are associated with acute LVO in patients with ischemic stroke. Prospective studies are ongoing to confirm this association and to test whether anticoagulation reduces the risk of recurrent embolism in this patient population.

Mechanical Thrombectomy Outcome Predictors in Stroke Patients with M2 Occlusion: A Single-Center Retrospective Study

Mechanical thrombectomy (MT) has demonstrated benefit in patients with acute ischemic stroke due to proximal large-vessel occlusion. However, it is unclear whether these results can be extrapolated to patients with an occlusion of the second segment (M2) of the middle cerebral artery (MCA). We sought to study outcomes in patients with M2 occlusion treated with MT and to better understand clinical predictors of these outcomes. We performed a single-center retrospective analysis of consecutive patients with acute MCA M2 segment occlusion who underwent stent retriever MT. We correlated clinical and radiographic outcomes with demographic, clinical, and technical characteristics. Thirty-seven patients were included in the analysis (median admission National Institutes of Health Stroke Scale [NIHSS] score, 15 [12-19], mean age 74 [67-80] years, 48.6% women). Good clinical outcome at 3 months (modified Rankin Scale ≤2) was achieved in 48.6% of patients. Baseline NIHSS was a predictor of clinical outcomes, based on modified Rankin Scale distribution at 3 months after MT (P= 0.015, odds ratio 1.63, 95% confidence interval 1.01-2.43). The results of our single-institution experience suggest that MT-based endovascular therapy for M2 occlusions is safe and effective. Baseline NIHSS was a predictor of outcomes in patients treated with MT for M2 segment occlusion of the MCA.

Abstract TMP67: Prehospital Screening for Large Vessel Occlusion and Bypass to Endovascular Stroke Centers: Using the Ambulance Clinical Triage for Acute Stroke Treatment Scale With Adaptation From DAWN and DEFUSE-3 Trials

Background and Purpose: The Ambulance Clinical Triage for Acute Stroke Treatment (ACT-FAST) scale uses two steps for large vessel occlusion (LVO) identification and a third step for transfer eligibility to endovascular-capable stroke centers. The purpose of this study was to modify the last step of ACT-FAST prehospital screening tool to include patients with a last known well &lt; 24 hours, and compare it with other existing stroke scales that are solely used to predict LVO. Methods: Patients with a final diagnosis of acute ischemic stroke who had a completed NIHSS score in the emergency department of my hospital between February 2017 and June 2018 were retrospectively investigated. Presence of LVO was determined by angiography imaging and/or physician diagnosis. The steps of the ACT-FAST scale used for LVO identification were compared with other current stroke prediction scales that utilize optimal cut-off scores. The third step of the ACT-FAST scale was modified for inclusion of patients with last known well time of &lt; 24 hours, and evaluated for ability to triage patients to endovascular-capable stroke centers. Results: 101 consecutive acute ischemic stroke patients, with an ED NIHSS score documented, were identified between February 2017 and June 2018. Of these 101 patients, 21 had a proximal LVO. The first two steps of the ACT-FAST scale to identify LVO had a higher accuracy compared to 3ISS ≥ 4, LAMS ≥ 4, CPSS =3, and PASS ≥ 2. The modified 3-step ACT-FAST showed 0.97 accuracy in ability to correctly triage patients to endovascular-capable stroke centers. Conclusions: The first 2 steps of the ACT-FAST scale showed superiority in this study for identifying LVO with less steps compared to other existing scales. The modified 3-step ACT-FAST scale showed high accuracy for appropriately recognizing endovascular-eligible patients. Further validation of the modified ACT-FAST scale is recommended with use of prospective studies within the field to determine patient benefit.

Abstract TP313: Communication Center Guided Prehospital Stroke Assessment Has Sustained Ability to Identify Patients With Large Vessel Occlusion

Introduction: There is need for sustainable models of effective prehospital stroke triage. Goal: Prospectively validate communication center guided prehospital identification of stroke patients with large vessel occlusion (LVO). Methods: We trained Alabama Trauma Communication Center (ATCC) paramedics in the previously derived 6 point Emergency Medical Stroke Assessment (EMSA). ATCC staff guided Emergency Medical Service (EMS) responders in the Birmingham Regional Emergency Medical Services System (BREMSS), and paged-out a hospital prenotification that included specific EMSA items (gaze, facial droop, arm drift, leg drift, naming, and repetition). Ongoing quality improvement was designed to enable the ATCC staff to effectively guide EMS responders. We derived the sensitivity, specificity, negative likelihood ratio (LR-), positive likelihood ratio (LR+), and receiver operator characteristics area under the curve (AUC) and 95% confidence intervals (CI) of ATCC guided EMSA for predicting a discharge diagnosis of LVO for patients transported to the University of Alabama at Birmingham. Results: We enrolled 521 patients from September 2016 through February 2018. Patients who only responded to pain (n=29, 5.6%) or who were unresponsive (n=21, 4%) were excluded. Of 471 patients analyzed, 247(52%) had a discharge diagnosis of stroke, including 182 (74%) acute ischemic stroke, 36 (14%) intracerebral hemorrhage, and 29 (11%) transient ischemic attack. There were 45 (18%) stroke patients with proximal LVO, including 31 middle cerebral artery stem, 12 internal carotid artery, and 2 basilar artery. Overall, an EMSA score ≥ 4 had sensitivity = 75.6%, specificity = 62.2%, LR- = 0.39, and LR+ = 2.00 for proximal LVO. During the first 9 months of the study, the EMSA AUC = 0.61 (CI = 0.45 – 0.77) compared to an AUC = 0.74 (CI = 0.64 – 0.84) during the second 9 month period of the study. Conclusions: EMS stroke medical control based on communication center guided prehospital stroke assessment and ongoing quality improvement is feasible and results in sustained ability to identify patients with LVO. Further studies are needed to evaluate the impact of guided prehospital triage of patients with suspected LVO on health outcomes.

Abstract TP17: Outcomes of Large Vessel Occlusion Patients in a Multi-Hospital System With Nihss&lt;6 Treated With Endovascular Thrombectomy vs Medical Management

With the publication of the 2018 updated acute stroke management guidelines, the American Stroke Association very publically proclaimed the safety and efficacy of endovascular thrombectomy (EVT) for the treatment of acute ischemic stroke due to proximal large vessel occlusion in individuals with NIHSS &gt;=6. The appropriate management of individuals who present with less severe large vessel occlusion (NIHSS &lt; 6) is less certain. Anecdotally, many individuals with low presenting NIHSS who are treated with EVT do well; conversely, about 20% of medically managed stroke patients deteriorate. We retrospectively analyzed stroke data obtained from a multi-hospital system for large vessel occlusion patients with admission NIHSS &lt; 6 discharged between January 2014 and May 2018, excluding those &lt;18 years of age and those with time of onset or last known well that is unknown or &gt;24hours. Outcomes included length of stay and percentage of patients who died in-hospital or were discharged to hospice, had a discharge other than to home or rehab, and had a discharge mRS ≥2. A total of 144 patients were included with 45% (n=65) treated by EVT. Those who were treated were younger, had higher admit NIHSS, and were more likely to be transfers. There were no significant differences in in-hospital mortality or discharge to hospice, discharge other than to home or rehab, or discharge mRS ≥2. EVT-treated patients had longer lengths of stay after adjusting for age, admission NIHSS, and LKW-to-door time (+36% (CI: 8, 64); p=0.012). Of EVT-treated patients, 3.1% (n=2) had a sICH and 90.3% (n=56 out of 62) had a successful reperfusion. When using medical judgment to evaluate the benefit of treating low NIHSS stroke, Interventionists are likely to select individuals who are more symptomatic or have been referred by an outside facility, a trend that achieved significance within our sample. Although the length of stay for individuals treated with EVT was on average one day longer than those who were medically managed, there was no significant difference in complications or outcomes between the two groups. Our findings are consistent with similar analyses and help argue for the safety of EVT for select individuals with presenting NIHSS &lt; 6.

Abstract 161: Interfacility Transfer for Mechanical Thrombectomy - Direct to Neuroangiography or CT Angiography First?

Objective: Faster time to mechanical thrombectomy (MT) is associated with better outcome in acute stroke. In patients transferred from other hospitals where a routine CT has already ruled out hemorrhage, transfer direct to angiography (DTA) suite may reduce door to groin time compared to transfer to CT angiography (CTA) first. However, this may result in unnecessary catheter angiography if many patients would have been excluded based on CTA results. We sought to determine how often CTA and repeat head CT changed the decision to proceed to MT. Methods: An internal transfer database at a comprehensive stroke center (CSC) was used to identify patients transferred from outside facilities for consideration of mechanical thrombectomy from July 2016 to May 2017. Detailed clinical and radiographic data was extracted using a standard case report form. Results: Of 187 patients transferred for MT, 171 underwent CT +/- CTA on arrival, 5 went DTA, and 11 were admitted without imaging or intervention. Among those undergoing CT +/- CTA on arrival, MT was aborted in 110 (64%) patients. Of these, 87 (79%) were aborted directly based on imaging findings, with absence of proximal large vessel occlusion (LVO) amenable to MT being the most common reason (69%), followed by rapid clinical improvement or mild deficit (7%). MT was aborted based on imaging findings in 36% of patients with NIHSS≥10 on arrival at CSC, and in 29% of patients with NIHSS≥15. In patients with outside hospital CTA demonstrating proximal LVO (n=48), MT was aborted in 48% on CSC arrival, mostly based on imaging findings (48%) or dramatic clinical improvement (31%). Use of tPA did not substantively modify any of these findings. CSC arrival to groin puncture tended to be shorter in the patients going DTA compared to CTA (median 39 v 54 min, p=0.06). Conclusions: While transfer DTA may be associated with faster door to groin puncture times, this might result in many patients undergoing unnecessary catheter angiography who would have been excluded based on CT +/- CTA findings. Even in transferred patients with severe stroke deficits on arrival, imaging excludes about 1/3 of patients from MT.

Abstract TP48: Mechanical Thrombectomy for Large Vessel Occlusion in Acute Ischemic Stroke Patients Presenting After 6 hours of Symptom Onset—A Meta-analysis of Randomized Controlled Clinical Trials

Background: The efficacy and safety of endovascular treatment for proximal large vessel occlusion after 6 hours of symptom onset have recently been studied in randomized controlled trials. We performed this meta-analysis to identify the combined effect of endovascular treatment on various outcomes in this patient population. Methods: We performed this meta-analysis of all available randomized controlled clinical studies that involved the use of endovascular treatment in after 6 hours of symptom onset. We calculated pooled odds ratios (ORs) and 95% confidence intervals (CIs) using random-effects models. The primary end point was a favorable outcome defined by a modified Rankin Scale (mRS) of 0 (no symptoms), 1 (no significant disability), or 2 (slight disability) at 90 days post-randomization. Other outcome variables included symptomatic intracerebral hemorrhage, excellent outcome (mRS 0-1), and mortality at 90 days post-randomization. Results: Three trials were identified that included 447 patients. The proportion of subjects who achieved a favorable outcome was significantly greater among those randomized to endovascular treatment compared with best medical treatment (445 subjects analyzed; OR 4.34; 95% CI, 2.65-7.14; P &lt; .001). Excellent outcome was also significantly greater among those randomized to endovascular treatment (445 subjects analyzed; odds ratio, 3.29; 95% CI, 1.98-5.46, P &lt; .001). Risk of symptomatic intracranial hemorrhage and mortality were similar between endovascular treatment and best medical treatment with p-value of 0.320 and 0.375, respectively. No risk of heterogeneity was observed in any of outcome variables. Conclusion: We found a prominent benefit (4 times higher odds) with endovascular treatment in appropriately selected patients with large vessel occlusion ischemic stroke presenting after 6 hours of symptom onset

Abstract WP279: Cardiac Biomarkers Predict Large Vessel Occlusion in Patients With Ischemic Stroke

Background and Purpose: Cardiac biomarkers may help identify stroke mechanisms and may aid in improving stroke prevention strategies. There is limited data on the association between these biomarkers and large vessel occlusion (LVO) in patients with acute ischemic stroke (AIS). We aim to determine the association between cardiac biomarkers [cardiac troponin and left atrial diameter (LAD)] and the presence of large vessel occlusion. Methods: Data was abstracted from a single center prospective AIS database over 18 months and included all patients with AIS with intracranial vascular imaging (CT angiogram or MR angiography). The presence of large vessel occlusion was defined as proximal LVO of the internal carotid artery terminus, middle cerebral artery (M1 or proximal M2), or basilar artery. Univariate analyses and predefined multivariable models were performed to determine the association between cardiac biomarkers [positive troponin (troponin &gt; 0.1) and LAD on transthoracic echocardiogram] and LVO adjusting for demographic factors (age and sex), risk factors (hypertension, diabetes, hyperlipidemia, history of stroke, congestive heart failure, coronary heart disease, and smoking), and atrial fibrillation (AF). Results: We identified 1234 patients admitted with AIS; 886 patients (71.8%) had intracranial MRA or CTA. Of those with imaging available, 398 patients (44.9%) had LVO and 232 patients (26.2%) underwent thrombectomy. There was an association between positive troponin and LVO after adjusting for age and sex and other risk factors [adjusted OR 1.97 (1.29-3.00), P=0.002)] and this association persisted after including AF in the model [adjusted OR 1.90 (1.24-2.93), p=0.003]. There was an association between LAD and LVO after adjusting for age, sex, and risk factors [adjusted OR per mm 1.04 (1.01-1.06), p = 0.002] but this association was not present when AF was added to the model [adjusted OR 1.01 (0.99-1.04), p = 0.323]. Sensitivity analyses using thrombectomy as an outcome yielded similar findings. Conclusion: Cardiac biomarkers predict acute LVO in patients with ischemic stroke. Prospective studies are ongoing to confirm this association and to test whether anticoagulation reduces the risk of recurrent embolism in this patient population.

High Variability in Neuronal Loss.

Background and Purpose- In the setting of acute ischemic stroke because of large-vessel occlusion (LVO) there is progressive loss of brain tissue which occurs in a time-dependent fashion previously quantified to be ≈1.9 million neurons per minute. However, this number represents an average and accumulating evidence suggests large individual variation. In this study, we aim to quantify the distribution and range in the rate of loss brain tissue across the entire spectrum of clinical phenotypes of anterior circulation LVO strokes encountered in clinical practice. Methods- Retrospective review of a prospectively acquired database of consecutive patients with anterior circulation stroke because of proximal LVO and appropriate ischemic core imaging was performed. Ischemic core volume was measured using automated software processing and time from last known well to imaging was recorded. Applying previously published methodology for brain loss quantification, we computed rate of brain tissue elements loss in proximal LVO stroke patients. Results- We studied 415 patients with internal carotid artery or middle cerebral artery (M1 segment) occlusion. Mean ischemic core volume was 50.4 mL and mean time to imaging from time from last known well (TLKW) was 8.7 hours, which is similar to previously published data, translates into a mean loss per minute of 2.03 million neurons, 14.8 billion synapses, and 12.8 km of myelinated fibers. However, the distribution of neuron loss was highly variable, ranging from <35 000 to >27 million cells per minute. Conclusions- Widely spread rates of infarct growth are observed in acute ischemic stroke because of proximal LVO with rate of neuron loss per minute ranging from <35 000 per minute in slow progressors to >27 million per minute in fast progressors, with a mean and median of 2 million and 0.9 million, respectively.

Thrombectomy for Acute Ischemic Stroke: Recent Insights and Future Directions

Mechanical thrombectomy has become the standard of care for acute ischemic stroke with proximal large vessel occlusions (LVO). This article reviews recent research relating to thrombectomy. Thrombectomy for anterior circulation stroke with proximal LVO was first shown to be highly efficacious within 6h of stroke onset, but "late-window" trials have further demonstrated efficacy until 24-h postonset in select patients with salvageable tissue. However, the concept of "time is brain" remains critical. Thrombectomy trials have further stimulated worldwide efforts to develop systems of care for rapid treatment of eligible patients. Thrombectomy is cost-effective and likely to have long-term efficacy for both disability and mortality outcomes. Thrombectomy is a highly efficacious acute stroke therapy. Enduring uncertainties include efficacy in patients with premorbid disability, posterior circulation, or more distal occlusions; use of bridging thrombolysis; and optimal techniques to achieve consistent revascularization and address tandem occlusions or stenoses.

Beyond Large Vessel Occlusion Strokes

Endovascular therapy is the standard of care for the treatment of proximal large vessel occlusion strokes. Its safety and efficacy in the treatment of distal intracranial occlusions has not been well studied. The data that support the findings of this study are available from the corresponding author on reasonable request. Retrospective review of a prospectively collected endovascular database (2010-2015, n=949) for all patients with distal intracranial occlusions treated endovascularly. Distal occlusions were defined as any segment of the anterior cerebral artery (ACA), posterior cerebral artery, or occlusion at or distal to the middle cerebral artery (MCA)-M3 opercular segment. Distal occlusions were treated in 69 patients. The mean age was 66.7±15.8 and 57% were male. Patients (29 [42%]) received intravenous tPA (tissue-type plasminogen activator). The median preprocedure National Institutes of Health Stroke Scale score was 18 (interquartile range, 13-23). The distal occlusion was the primary treatment location in 45 patients, in 23 patients the distal occlusion was treated as a rescue strategy after successful treatment of a proximal large vessel occlusion strokes, and 1 patient had both primary and rescue treatment. The locations of the primary cases were MCA-M3 (n=21), ACA alone (n=8), ACA with a concomitant MCA-M1 or MCA-M2 (n=10), ACA with a concomitant MCA-M3 (n=3), and posterior cerebral artery (n=3). The locations of the rescue cases were MCA-M3 (n=11), ACA (n=7), posterior cerebral artery (n=4), and both MCA-M3 and ACA (n=1). There was a single patient with primary ACA and MCA-M2 occlusions treated, who then had a rescue MCA-M3 thrombectomy addressed after initial reperfusion. The most common treatment modalities used were stent-retrievers (n=37, 54%), intra-arterial tPA (n=36, 52%), and thromboaspiration (n=31, 45%). Near complete or complete reperfusion of the distal territory (modified Treatment In Cerebral Ischemia [mTICI] 2b-3) was achieved in 57 cases (83%). Three parenchymal hematomas (4%) occurred in the territory of the treated distal occlusion with 2 of these patients also receiving intravenous tPA. At 90 days, 21 patients (30%) had a modified Rankin Scale score of 0 to 2 and 14 (20%) had died. Distal intracranial occlusions can be treated safely and successfully with endovascular therapy. These results need to be corroborated by larger prospective controlled studies.

Clinical Outcomes of Endovascular Treatment within 24 Hours in Patients with Mild Ischemic Stroke and Perfusion Imaging Selection

Endovascular thrombectomy has been accepted as the standard of care for patients with acute ischemic stroke. Our aim was to investigate the clinical outcomes of patients with mild ischemic stroke with acute proximal large-vessel occlusion after endovascular treatment within 24 hours of symptom onset. Between January 2014 and August 2017, ninety-three Chinese patients with mild ischemic stroke (NIHSS scores, 0-8) and large-vessel occlusion with endovascular treatment were retrospectively enrolled from 7 comprehensive stroke centers. They were divided into 2 groups: ≤6 hours and 6-24 hours from symptom onset to groin puncture. We analyzed their modified Rankin Scale scores at 90 days, symptomatic intracranial hemorrhage at 48 hours, and mortality during 90 days. Multivariable linear regression analysis was used to identify predictors for NIHSS shift after discharge. Twenty-nine patients received endovascular treatment within 6-24 hours after symptom onset and had an imaging mismatch based on perfusion CT or diffusion-weighted MR imaging. There were no substantial differences between the 2 groups in 90-day functional independence (P = .54) and the risks of the combination of symptomatic intracranial hemorrhage and death (P = .72). Two significant indicators of NIHSS shift were 48-hour symptomatic intracranial hemorrhage (unstandardized β = 7.28; 95% CI, 3.48-11.1; P < .001) and baseline systolic blood pressure (unstandardized β = 0.08; 95% CI, 0.03-0.14; P = .005). Patients with mild ischemic stroke and large-vessel occlusion in the anterior circulation, an imaging mismatch, and endovascular treatment within 6-24 hours of initial symptoms showed no heterogeneity in the efficacy and safety outcome compared with those treated ≤6 hours from symptom onset.

Clinical and Technological Approaches to the Prehospital Diagnosis of Large Vessel Occlusion.

Endovascular thrombectomy is highly effective for the treatment of acute ischemic stroke because of proximal large vessel occlusion,1 but the treatment effect falls rapidly with time.2 Almost all patients with severe stroke are transported by an emergency medical service (EMS), which is independently associated with reduced time to treatment.3 Nevertheless, delays are frequent in patients arriving for endovascular thrombectomy via secondary transport from another facility.1 To reduce time to treatment, some jurisdictions are exploring redirect policies, whereby patients bypass a closer primary stroke center and are instead transported directly to endovascular-capable facilities.4 Instituting a pathway for hospital bypass is a complex undertaking that involves the coordination of diverse stakeholders.4 Core components include patient selection criteria, interfacility agreements (eg, transfer and repatriation), paramedic training, and outcome evaluation. Approaches to patient selection have drawn recent interest, particularly in the use of simplified standardized clinical examinations for the diagnosis of proximal large vessel occlusion. In this review, we review current clinical and technological approaches to patient selection and discuss implementation in the context of jurisdictional features. The database search terms for this review article are provided in the online-only Data Supplement. Proximal large vessel occlusion is the substrate for endovascular thrombectomy—field diagnosis of large vessel occlusion is the sine qua non for hospital bypass. In this section, we discuss important caveats in prehospital diagnosis and follow with a review of specific clinical and technological approaches. ### Caveats Three caveats apply to the interpretation of studies of diagnostic tests for transport decision making: First, diagnosis is primarily a means to support transport decision making, not an end. If 2 diagnoses share the same transport destination, then it might not be so important to distinguish between them. For example, distinguishing between intracerebral hemorrhage (ICH) and large vessel occlusion may be …

Abstract WP4: Age and NIHSS score Predict Outcome in Patients With Mild Stroke and Proximal Large Vessel Occlusion

Background: Current guidelines recommend mechanical thrombectomy for patients with anterior circulation proximal large vessel occlusion (LVO), NIHSS≥ 6, within 6 hours from symptom onset, with a NCCT ASPECTS of 6 or higher. It remains unclear whether patients with NIHSS &lt; 6 and LVO should also undergo mechanical thrombectomy. The benefit of intervention, associated risk and predictors of outcome in this patient population has not been studied. We sought to determine the natural history and predictors of good outcome in patients NIHSS&lt;6 and evidence of LVO who did not undergo mechanical thrombectomy. Methods: We abstracted data from our ischemic stroke prospective database and included patients with NIHSS &lt; 6 and presence of proximal large vessel occlusion admitted between January 1 st , 2015 and April 30 th , 2017. The outcome, 90-day mRS, was collected via a phone call at 90 days. Patients were divided into two groups: good outcome (90-day mRS 0-1) and poor outcome (90-day mRS 2-6). We compared baseline demographics, treatments, neuroimaging data (ASPECTS score), and vascular imaging findings (location of occlusion, collateral score: poor, good, and excellent) between the two groups. P-value &lt; 0.05 was considered significant. Results: A total of 68 patients were identified; 50/68 did not undergo mechanical thrombectomy; out of which only 25/50 (50%) had a good 90-day outcome. Patients with a good outcome were younger (Mean ± SD, 69.3 ±3.2 vs 76 ± 2.2 years of age, p=0.033) and had a lower median admission NIHSS score (3 vs. 4, p=0.026).There was a trend towards good outcome with ICA and M1- MCA occlusion when compared to other locations but this was not statistically significant. Other variables also did not achieve statistical significance. Conclusion: Younger age and lower NIHSS predict good functional outcome in patients with LVO and mild deficits. Larger prospective studies are needed to verify our findings and explore the role of mechanical thrombectomy in patients who might be at risk of poor outcome.

Abstract WP326: Fever Promotes Worse Outcomes in Reperfused Patients Irrespective of Febrile Duration

Introduction: Fever following acute ischemic stroke (AIS) promotes greater consumption of ischemic penumbra despite reperfusion; however, the influence of timing of onset and duration of fever remains unexplored. We assessed the impact of such temporal features on infarct growth and clinical outcome in AIS, hypothesizing a dose-dependent negative response to sustained fever. Methods: Retrospective study of AIS patients presenting with proximal large vessel occlusion within 12h of onset, and achieving reperfusion (mTICI 2b/3). Pretreatment CTP was obtained in all subjects in a fully automated environment (RAPID) for segmentation of ischemic core and penumbral mismatch volumes. Final infarct volumes (FIV) were measured by DWI, and relative infarct growth (RIG) computed as (FIV-CTPcore/CTPmismatch). Systemic temperatures were obtained up to q15 minutes from presentation to DWI. Fever (&gt;37.5) onset and duration were documented. Pearson’s correlation and linear and logistic regressions tested the association of fever onset and duration vs. RIG and favorable clinical outcome (90d mRS≤2). Results: 119 subjects (59 men, age 63±14 yrs) met inclusion. Median[IQR] NIHSS=18[8]; last known well to groin puncture=355min[310]; median[IQR] core, mismatch, and FIV=9.6[23.8], 109[104], and 19.6[37]ml, respectively. Median fever duration=9h. Fever duration and time to onset were not independently associated with RIG (p=0.4, 0.6). The best fit model for prediction of RIG included fever, procedure duration and initial core. The OR for 90d mRS≤2 in febrile patients controlling for fever onset, age, NIHSS, core and procedure parameters was 0.6 (0.14-2.85). The adjusted OR for 90d mRS≤2 given one additional hour of febrile time was non-significant (0.99, 0.9-1.0). Earlier timing of fever onset was independently correlated to clinical outcome (p=0.04). Conclusions: While fever promotes infarct growth despite reperfusion, these findings suggest duration of fever is less influential upon imaging and clinical outcomes than hypothesized, with the negative impact of fever in the early aftermath of AIS driving worse outcomes irrespective of duration. The findings underscore the importance of temperature control during early temperature dysregulation after AIS.

Evaluating patients for thrombectomy.

The treatment of acute ischemic stroke patients with a proximal large vessel occlusion (LVO) in the anterior circulation has seen tremendous advances initially with the demonstration of the substantial benefit of thrombectomy within 6-h of stroke onset and then with the demonstration of thrombectomy in carefully selected patients up to 24-h from onset. In both the early and late time windows, imaging played an important role in patient selection, especially in the later time window trials where very strict imaging inclusion criteria were employed to identify patients with a small/moderate sized ischemic core on computed tomography perfusion scanning and diffusion-weighted magnetic resonance imaging. In clinical practice, it is important to identify LVO patients quickly so several scoring scales have been developed to help route appropriate patients to a thrombectomy capable center. The recently reported thrombectomy trials left many unanswered questions such as do patients with more distal vessel occlusions benefit, do patients with LVO and mild clinical deficits benefit from thrombectomy, what is the largest extent of baseline ischemic core that still benefits from thrombectomy and what is the best approach to anesthesia with thrombectomy. These questions and other are being addressed in ongoing and future clinical trials that will likely expand the indications and safety for this powerfully effective therapy and also determine if neuroprotection is synergistic with thrombectomy.

Mechanical thrombectomy for acute ischemic stroke with occlusion of the M2 segment of the middle cerebral artery: a meta-analysis

BackgroundEndovascular thrombectomy has demonstrated benefit for patients with acute ischemic stroke from proximal large vessel occlusion. However, limited evidence is available from recent randomized trials on the role of thrombectomy...