Headpulse measurement can reliably identify large-vessel occlusion stroke in prehospital suspected stroke patients: Results from the EPISODE-PS-COVID study

BACKGROUND

Large-vessel occlusion (LVO) stroke represents one-third of acute ischemic stroke (AIS) in the United States but causes two-thirds of poststroke dependence and >90% of poststroke mortality. Prehospital LVO stroke detection permits efficient emergency medical systems (EMS) transport to an endovascular thrombectomy (EVT)-capable center. Our primary objective was to determine the feasibility of using a cranial accelerometry (CA) headset device for prehospital LVO stroke detection. Our secondary objective was development of an algorithm capable of distinguishing LVO stroke from other conditions.

METHODS

We prospectively enrolled consecutive adult patients suspected of acute stroke from 11 study hospitals in four different U.S. geographical regions over a 21-month period. Patients received device placement by prehospital EMS personnel. Headset data were matched with clinical data following informed consent. LVO stroke diagnosis was determined by medical chart review. The device was trained using device data and Los Angeles Motor Scale (LAMS) examination components. A binary threshold was selected for comparison of device performance to LAMS scores.

RESULTS

A total of 594 subjects were enrolled, including 183 subjects who received the second-generation device. Usable data were captured in 158 patients (86.3%). Study subjects were 53% female and 56% Black/African American, with median age 69 years. Twenty-six (16.4%) patients had LVO and 132 (83.6%) were not LVO (not-LVO AIS, 33; intracerebral hemorrhage, nine; stroke mimics, 90). COVID-19 testing and positivity rates (10.6%) were not different between groups. We found a sensitivity of 38.5% and specificity of 82.7% for LAMS ≥ 4 in detecting LVO stroke versus a sensitivity of 84.6% (p < 0.0015 for superiority) and specificity of 82.6% (p = 0.81 for superiority) for the device algorithm (CA + LAMS).

CONCLUSIONS

Obtaining adequate recordings with a CA headset is highly feasible in the prehospital environment. Use of the device algorithm incorporating both CA and LAMS data for LVO detection resulted in significantly higher sensitivity without reduced specificity when compared to the use of LAMS alone.

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

BACKGROUND

Large vessel occlusion (LVO) prediction scales are used to triage prehospital suspected stroke patients with a high probability of LVO stroke to endovascular therapy centers. The sensitivities of these scales in the 6-to-24-h time window are unknown. Higher scale score thresholds are typically less sensitive and more specific. Knowing the highest scale score thresholds that remain sensitive could inform threshold selection for clinical use. Sensitivities may also vary between left and right-sided LVOs.

METHODS

LVO prediction scale scores were retrospectively calculated using the National Institutes of Health Stroke Scale (NIHSS) scores of patients enrolled in the DAWN Trial. All patients had last known well times between 6 and 24 h, NIHSS scores ≥ 10, intracranial internal carotid artery or proximal middle cerebral artery occlusions, and mismatches between their clinical severities and infarct core volumes. Scale thresholds with sensitivities ≥ 85% were identified, along with scores ≥ 5% more sensitive for left or right-sided LVOs. Specificities could not be calculated because all patients had LVOs.

RESULTS

A total of 201 out of 206 patients had the required NIHSS subitem scores. CPSS = 3, C-STAT ≥ 2, FAST-ED ≥ 4, G-FAST ≥ 3, RACE ≥ 5, and SAVE ≥ 3 were the highest thresholds that were still 85% sensitive for DAWN Trial LVO stroke patients. RACE ≥ 5 was the only typically used score threshold more sensitive for right-sided LVOs, though similar small differences were seen for other scales at higher thresholds.

CONCLUSIONS

Our findings likely represent the maximum sensitivities of the LVO prediction scales tested for ideal thrombectomy candidates in the 6-to-24-h time window because NIHSS scores were documented in hospitals during a clinical trial rather than in the prehospital setting. Patients with NIHSS scores < 10 or more distal LVOs would lower sensitivities further. Selecting even higher scale thresholds for LVO triage would lead to many missed LVO strokes.

Headpulse Biometric Measures Following Concussion in Young Adult Athletes

Importance

Concussions are common in sports. Return-to-play protocols can be enhanced by objective biometrics.

Objective

To characterize temporal changes of headpulse, a digital biometric, in athletes with sports-related concussion; to explore the association of unstructured physical activity with headpulse changes.

Design, Setting, and Participants

This cohort study included headpulse measurements from players in the highest level of amateur Australian Rules Football in South Australia. Analysis included feasibility and validation phases, with the feasibility cohort recruited between August 5, 2021, and September 10, 2021, and the validation cohort recruited between May 5, 2022, and September 3, 2022. Data were analyzed October 2022 through January 2023.

Interventions

Cranial accelerometry detected micromovements of the head following cardiac contraction (what we have described as "headpulse"). Headpulse was serially recorded for 1 month in concussed individuals.

Main Outcomes and Measures

Headpulse waveforms underwent frequency transformation analysis per prespecified algorithm. Result Z scores were calculated. Headpulse Z scores exceeding 2 (2 SDs from control means) met an abnormality threshold. Headpulse sensitivity, timing, and duration of change were determined.

Results

A total of 59 control and 43 concussed individuals (44 total concussions; 1 control also concussed, 1 concussed individual injured twice) provided headpulse measurements. The feasibility cohort (all male) included 17 control (median [IQR] age, 23 [19-28] years) and 15 concussed individuals (median [IQR] age, 21 [19-23] years). The validation cohort included 25 female (median [IQR] age, 21 [20-22] years) and 17 male (median [IQR] age, 26 [23-29] years) control individuals, and 8 female (median [IQR] age, 28 [20-31] years) and 20 male (median [IQR] age, 21 [19-23] years) concussed individuals. Headpulse reached abnormality threshold in 26 of 32 concussed individuals (81%; 9% on day 0, 50% by day 2, 90% by day 14). Headpulse alterations lasted 14 days longer than symptoms and were exacerbated by return-to-play or unsupervised physical activity.

Conclusions and Relevance

In this study of 101 amateur Australian Rules Football athletes, the digital headpulse biometric was evaluated in 44 sports-related concussions. Compared with controls, new headpulse changes occurred after concussion; this objective metric may complement return-to-play protocols.

A Survey on Monitoring and Management of Cerebral Vasospasm and Delayed Cerebral Ischemia After Subarachnoid Hemorrhage: The Mantra Study

INTRODUCTION

Cerebral infarction from delayed cerebral ischemia (DCI) is a leading cause of poor neurological outcome after aneurysmal subarachnoid hemorrhage (aSAH). We performed an international clinical practice survey to identify monitoring and management strategies for cerebral vasospasm associated with DCI in aSAH patients requiring intensive care unit admission.

METHODS

The survey questionnaire was available on the European Society of Intensive Care Medicine (May 2021-June 2022) and Neurocritical Care Society (April - June 2022) websites following endorsement by these societies.

RESULTS

There were 292 respondents from 240 centers in 38 countries. In conscious aSAH patients or those able to tolerate an interruption of sedation, neurological examination was the most frequently used diagnostic modality to detect delayed neurological deficits related to DCI caused by cerebral vasospasm (278 respondents, 95.2%), while in unconscious patients transcranial Doppler/cerebral ultrasound was most frequently used modality (200, 68.5%). Computed tomography angiography was mostly used to confirm the presence of vasospasm as a cause of DCI. Nimodipine was administered for DCI prophylaxis by the majority of the respondents (257, 88%), mostly by an enteral route (206, 71.3%). If there was a significant reduction in arterial blood pressure after nimodipine administration, a vasopressor was added and nimodipine dosage unchanged (131, 45.6%) or reduced (122, 42.5%). Induced hypertension was used by 244 (85%) respondents as first-line management of DCI related to vasospasm; 168 (59.6%) respondents used an intra-arterial procedure as second-line therapy.

CONCLUSIONS

This survey demonstrated variability in monitoring and management strategies for DCI related to vasospasm after aSAH. These findings may be helpful in promoting educational programs and future research.

End-Of-Life Care in the Potential Donor after Circulatory Death: A Systematic Review

Background

Donation after circulatory death (DCD) is becoming increasingly common, yet little is known about the way potential donors receive end-of-life care.

Purpose

The aims of this systematic review are to describe the current practice in end-of-life care for potential donors and identify metrics that are being used to assess discomfort among these patients.

Research design and Study Sample

This review encompasses published literature between June 1, 2000 and June 31, 2020 of end-of-life care received by potential DCD patients. The population of interest was defined as patients eligible for Maastracht classification III donation after circulatory death for a solid organ transplantation. Outcomes examined included: analgesic or palliative protocols, and surrogates of discomfort (eg dyspnea, agitation).

Results

Among 141 unique articles, 27 studies were included for full review. The primary reason for exclusion was lack of protocol description, or lack of reporting on analgesic medications. No primary research studies specifically examined distress in the DCD eligible population. Numerous professional guidelines were identified. Surveys of critical care practitioners identified concerns regarding the impact of symptom management on hastening the dying process in the DCD population as a potential barrier to end-of-life palliative treatment.

Conclusions

There is a paucity of empirical evidence for end-of-life symptom assessment and management for DCD patients. Key evidence gaps identified for DCD include the need for: i) a multidisciplinary structure of treatment teams and preferred environment for DCD, ii) objective tools for monitoring of distress in this patient population, and iii) evidence guiding the administration of analgesic medications following withdrawal of life sustaining therapy.

Large vessel occlusion prediction scales provide high negative but low positive predictive values in prehospital suspected stroke patients

Introduction

We studied a registry of Emergency Medical Systems (EMS) identified prehospital suspected stroke patients brought to an academic endovascular capable hospital over 1 year to assess the prevalence of disease and externally validate large vessel occlusion (LVO) stroke prediction scales with a focus on predictive values.

Methods

All patients had last known well times within 6 hours and a positive prehospital Cincinnati Prehospital Stroke Scale. LVO prediction scale scores were retrospectively calculated from emergency department arrival National Institutes of Health Stroke Scale scores. Final diagnoses were determined by chart review. Prevalence and diagnostic performance statistics were calculated. We prespecified analyses to identify scale thresholds with positive predictive values (PPVs) ≥80% and negative predictive values (NPVs) ≥95%. A secondary analysis identified thresholds with PPVs ≥50%.

Results

Of 220 EMS transported patients, 13.6% had LVO stroke, 15.9% had intracranial haemorrhage, 20.5% had non-LVO stroke and 50% had stroke mimic diagnoses. LVO stroke prevalence was 15.8% among the 184 diagnostic performance study eligible patients. Only Field Assessment Stroke Triage for Emergency Destination (FAST-ED) ≥7 had a PPV ≥80%, but this threshold missed 83% of LVO strokes. FAST-ED ≥6, Prehospital Acute Severity Scale =3 and Rapid Arterial oCclusion Evaluation ≥7 had PPVs ≥50% but sensitivities were <50%. Several standard and lower alternative scale thresholds achieved NPVs ≥95%, but false positives were common.

Conclusions

Diagnostic performance tradeoffs of LVO prediction scales limited their ability to achieve high PPVs without missing most LVO strokes. Multiple scales provided high NPV thresholds, but these were associated with many false positives.

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

BACKGROUND AND PURPOSE

Collaterals govern the pace and severity of cerebral ischemia, distinguishing fast or slow progressors and corresponding therapeutic opportunities. The fate of sustained collateral perfusion or collateral failure is poorly characterized. We evaluated the nature and impact of collaterals on outcomes in the late time window DAWN trial (Diffusion-Weighted Imaging or Computed Tomography Perfusion Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention With Trevo).

METHODS

The DAWN Imaging Core Lab prospectively scored collateral grade on baseline computed tomography angiography (CTA; endovascular and control arms) and digital subtraction angiography (DSA; endovascular arm only), blinded to all other data. CTA collaterals were graded with the Tan scale and DSA collaterals were scored by ASITN grade (American Society of Interventional and Therapeutic Neuroradiology collateral score). Descriptive statistics characterized CTA collateral grade in all DAWN subjects and DSA collaterals in the endovascular arm. The relationship between collateral grade and day 90 outcomes were separately analyzed for each treatment arm.

RESULTS

Collateral circulation to the ischemic territory was evaluated on CTA (n=144; median 2, 0-3) and DSA (n=57; median 2, 1-4) before thrombectomy in 161 DAWN subjects (mean age 69.8±13.6 years; 55.3% women; 91 endovascular therapy, 70 control). CTA revealed a broad range of collaterals (Tan grade 3, n=64 [44%]; 2, n=45 [31%]; 1, n=31 [22%]; 0, n=4 [3%]). DSA also showed a diverse range of collateral grades (ASITN grade 4, n=4; 3, n=22; 2, n=27; 1, n=4). Across treatment arms, baseline demographics, clinical variables except atrial fibrillation (41.6% endovascular versus 25.0% controls, P=0.04), and CTA collateral grades were balanced. Differences were seen across the 3 levels of collateral flow (good, fair, poor) for baseline National Institutes of Health Stroke Scale, blood glucose <150, diabetes, previous ischemic stroke, baseline and 24-hour core infarct volume, baseline and 24-hour Alberta Stroke Program Early CT Score, dramatic infarct progression, final Thrombolysis in Cerebral Infarction 2b+, and death. Collateral flow was a significant predictor of 90-day modified Rankin Scale score of 0 to 2 in the endovascular arm, with 43.7% (31/71) of subjects with good collaterals, 30.8% (16/52) of subjects with fair collaterals, and 17.7% (6/34) of subjects with poor collaterals reaching modified Rankin Scale score of 0 to 2 at 90 days (P=0.026).

CONCLUSIONS

DAWN subjects enrolled at 6 to 24 hours after onset with limited infarct cores had a wide range of collateral grades on both CTA and DSA. Even in this late time window, better collaterals lead to slower stroke progression and better functional outcomes.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02142283.

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

BACKGROUND AND PURPOSE

The impact of baseline ischemia on Alberta Stroke Program Early CT Score (ASPECTS) and evolution over 24 hours may be distinct in late thrombectomy. We analyzed predictors of serial ASPECTS and clinical outcomes in the DAWN trial (Diffusion-Weighted Imaging or CTP Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention With Trevo).

METHODS

The DAWN Imaging Core Laboratory independently scored ASPECTS at baseline and 24 hours. Descriptive statistics characterized ASPECTS on computed tomography/magnetic resonance imaging at baseline and 24 hours, delineating ASPECTS change over 24 hours.

RESULTS

206 subjects (mean age 70.0±13.7 years; 54.9% (n=113) female; baseline National Institutes of Health Stroke Scale median (interquartile range) 17 (13, 21) were included. Baseline ASPECTS was median (interquartile range) 8.0 (7-8), with 92/205 (44.9%) between 0 and 7 and 113/205 (55.1%) 8 and 10. 24-hour ASPECTS was median 6.0 (4-8), with ASPECTS change or infarct evolution having median -1, ranging from -8 to +2. Multivariable logistic regression showed older age (odds ratio [OR] for 10-year interval, 1.26 [95% CI, 1.02-1.55], P=0.030) and dyslipidemia (OR, 1.84 [95% CI, 1.06-3.19], P=0.031) were independently associated with higher baseline ASPECTS. Higher 24-hour ASPECTS was predicted by endovascular treatment (OR, 2.76 [95% CI, 1.58-4.81], P=0.0004), baseline glucose <150 mg/dL (OR, 2.86 [95% CI, 1.50-5.46], P=0.001), lower baseline National Institutes of Health Stroke Scale (OR, 0.93 [95% CI, 0.89-0.98], P=0.010), and older age (OR for 10-year interval, 1.25 [95% CI, 1.01-1.55], P=0.041). Internal carotid artery lesion location (OR, 0.47 [95% CI, 0.24-0.89], P=0.021) was inversely related to 24-hour ASPECTS. Good clinical outcome (day 90 modified Rankin Scale score 0-2) was predicted by 24-hour ASPECTS (OR, 1.46 [95% CI, 1.08-1.96], P=0.014). Extensive infarct evolution (ASPECTS decrease ≥6) occurred in 14/201 (7.0%). Elevated baseline serum glucose ≥150 mg/dL was a predictor of ASPECTS decrease of ≥4 points (OR, 2.78 [95% CI, 1.21-6.35] P=0.016) as was internal carotid artery occlusion (OR, 2.49 [95% CI, 1.05-5.88]; P=0.038). ASPECTS change was influenced by treatment arm (P=0.001 by Wilcoxon), including 0 ASPECTS change in 42/105 (40.0%) of the endovascular arm and only 20/96 (20.8%) of the medical arm.

CONCLUSIONS

DAWN subjects enrolled with small infarct cores had a broad range of baseline ASPECTS. Twenty-four-hour ASPECTS, strikingly influenced by endovascular therapy, predicted good clinical outcomes. REGISTRATION: https://www.clinicaltrials.gov; Unique identifier: NCT02142283.

Abstract P137: Large Vessel Occlusion Prediction Scale Thresholds That Are Sensitive for DAWN Trial Participants

Introduction: Large Vessel Occlusion (LVO) prediction scales are used to triage prehospital suspected stroke patients with a high probability of LVO stroke to endovascular therapy centers. The sensitivities of these scales in the 6 to 24 hour window are unknown. Higher scale score thresholds are typically less sensitive and more specific. Knowing the highest scale score thresholds that remain sensitive could inform threshold selection for clinical use. Sensitivities may also vary between left and right sided LVOs.

Methods: LVO prediction scale scores were retrospectively calculated using the NIHSS sub-item scores of patients enrolled in the DAWN Trial. All patients had last known well times between 6 to 24 hours, NIHSS scores ≥ 10, intracranial ICA or proximal MCA occlusions, and mismatches between their exam severities and infarct core volumes. Scale thresholds with sensitivities ≥ 85% were identified. Scores ≥ 5% more sensitive for left or right sided LVOs were identified. Specificities could not be calculated because all DAWN Trial patients had LVOs.

Results: 201 out of 206 patients had the required NIHSS sub-item scores. The highest score thresholds that maintained sensitivities ≥ 85% are bolded in the table.

Conclusions: CPSS = 3, C-STAT ≥ 2, FAST-ED ≥ 4, G-FAST ≥ 3, RACE ≥ 5, and SAVE ≥ 3 are likely the highest thresholds that can be selected for extended window LVO triage without missing more than 15% of DAWN Trial eligible LVO strokes. For CPSS and SAVE, these are higher than the thresholds suggested by prior studies. CPSS = 3 and RACE ≥ 5 were more sensitive for right sided LVOs. These findings represent the maximum anticipated sensitivities of LVO prediction scales since the NIHSS scores were documented in hospitals during a clinical trial rather than in the prehospital setting. Inclusion of lower NIHSS or more distal LVO patients would lower sensitivities further. Selecting even higher scale thresholds for LVO triage would lead to many missed LVO strokes.

Abstract 30: Prediction Scale Thresholds Selected to Rule Out Large Vessel Occlusion Stroke Result in Very Low Positive Predictive Values and Many False Positives

Introduction: Many prior large vessel occlusion (LVO) prevalence and prediction scale accuracy studies have not had samples representative of a prehospital suspected stroke population. To address this, we studied emergency medical systems (EMS) identified prehospital suspected stroke patients brought to the Emergency Department (ED) at Zuckerberg San Francisco General Hospital from July 2017 to July 2018.

Methods: Patients were eligible for the prevalence study if the EMS prehospital alert call included suspected stroke with a last known well time within 6 hours and a positive Cincinnati Prehospital Stroke Scale. LVO prediction scale scores were retrospectively calculated from arrival NIHSS subitems. We excluded patients missing NIHSS scores and scales requiring non-NIHSS data. LVO stroke included internal carotid, M1, M2, or basilar arteries. Diagnoses were determined by chart review. Prevalences, scale scores, and accuracy statistics were then calculated. We prespecified that negative results of scale thresholds must reduce the post-test probability to ≤5% to rule out LVO stroke and positive results must increase the post-test probability to ≥80% to rule in LVO stroke.

Results: Of 220 EMS transported patients there were 30 LVO strokes (13.6%), 35 ICHs (15.9%), 45 non-LVO strokes (20.5%), and 110 mimics (50%). There were 184 patients eligible for the LVO prediction study. Table 1 shows the accuracy statistics of qualifying scale thresholds.

False positive rates ranged from 58% to 80%. Only FAST-ED ≥7 resulted in a positive predictive value (PPV) of ≥80% but this missed 83% of LVO strokes.

Conclusions: The prevalence of LVO stroke among EMS suspected acute stroke patients brought to our ED over one year was 13.6%. Prediction scale thresholds selected to rule out LVO stroke result in very low PPVs and many false positives. No scale achieved a PPV above 50% while maintaining a sensitivity above 50% suggesting limitations in the ability of scales to rule in LVO stroke.

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

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

Benefit of Endovascular Thrombectomy by Mode of Onset

Background and Purpose—

It is unknown whether the benefit of thrombectomy in late presenting acute stroke patients with imaging evidence of clinical-infarct mismatch is different in patients presenting with wake-up stroke compared with those presenting with witnessed onset or unwitnessed onset.

Methods—

Prespecified secondary analysis was performed from DAWN (Diffusion Weighted Imaging [DWI] or Computerized Tomography Perfusion [CTP] Assessment With Clinical Mismatch in the Triage of Wake Up and Late Presenting Strokes Undergoing Neurointervention), a multicenter, prospective, randomized clinical trial with blinded end point assessment comparing thrombectomy with the Trevo device against standard medical therapy in patients with acute stroke and clinical-infarct mismatch presenting 6 to 24 hour after the time last seen well. For the purposes of this study, the primary outcome was the proportion of modified Rankin Scale score 0 to 2 at 90 days. Univariable analysis and multivariable logistic regression was used to assess the relationship between outcome and mode of onset.

Results—

All 206 enrolled patients were included in the study. Mode of onset was: wake-up stroke (55.3%, n=114), witnessed onset (12.1%, n=25), and unwitnessed onset (32.5%, n=67) with median time last seen well to randomization (13.4±3.7, 10.0±3.7, 14.1±4.9 hours) respectively. Rates of 90-day modified Rankin Scale score of 0 to 2 and symptomatic intracerebral hemorrhage in the thrombectomy arm were not statistically different across patient onset subtypes ( P =0.79 and P =0.40, respectively). The benefit of thrombectomy compared with best medical therapy was maintained across all 3 onset modes (rates of 90-day modified Rankin Scale score of 0 to 2 in patients allocated to thrombectomy versus control: wake-up stroke—49.3% versus 10.6%, witnessed onset—63.6% versus 21.4%, UW—41.4% versus 13.2%; P ×interaction=0.79). In univariable and multivariable analyses, mode of onset was not identified as a significant predictor of modified Rankin Scale score 0 to 2 at 90 days.

Conclusions—

In patients with acute ischemic stroke presenting between 6 and 24 hours from time last seen well and harboring clinical-infarct mismatch, the benefit of thrombectomy was similar regardless of the wake-up, unwitnessed, or witnessed mode of onset.

Outcome in Direct Versus Transfer Patients in the DAWN Controlled Trial

Background and Purpose—

The impact of transfer status on clinical outcomes in the DAWN (DWI or CTP Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention With Trevo) population is unknown. We analyzed workflow and clinical outcome differences between direct versus transfer patients in the DAWN population.

Methods—

The following time metrics were analyzed for each group: (1) last known well to hospital arrival, (2) hospital arrival to eligibility imaging, (3) hospital arrival to arterial puncture, (4) qualifying imaging to arterial puncture, (5) last known well to arterial puncture, (6) last known well to reperfusion. The primary end point was the rate of functional independence (90-day modified Rankin Scale [mRS] score, 0–2). Using univariate unconditional logistic regression, we calculated odds ratios and 95% CIs for the association between clinically relevant time metrics, transfer status, and functional independence (mRS 0–2).

Results—

A total of 206 patients were enrolled. Among these, 121 (59%) patients were transferred, and 85 (41%) patients presented directly to a thrombectomy capable center. Median time last seen well to hospital arrival time was similar between the 2 groups (678 versus 696 minutes). The time from hospital arrival to groin puncture was significantly longer in direct patients compared with transferred patients 140 minutes (interquartile range, 105.5–177.5 minutes) and 88 minutes (interquartile range, 55–125 minutes), respectively ( P <0.001). Differences in treatment effect or differences in rates of mRS 0–2 in the thrombectomy treated patients were not statistically significant in direct versus transfer patients (odds ratios for mRS 0–2, thrombectomy versus control, were 5.62 in direct and 6.63 in transfer patients, respectively, Breslow-Day P =0.817).

Conclusions—

Although transfer patients had a faster door to puncture time, benefits of thrombectomy, and rates of mRS 0 to 2 in the treatment group were similar between direct and transferred patients in the DAWN population. These results may inform prehospital and primary stroke centers triage protocols in patients presenting in the late time window.

Clinical Trial Registration—

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02142283.

Endovascular Stroke Therapy

Ischemic stroke is a leading cause of death and disability throughout the world and is both preventable and treatable. This review focuses on the treatment of the most severe form of ischemic stroke, namely large-vessel ischemic stroke, using endovascular techniques. Such therapies were proven effective in 2015. These therapies are among the most beneficial surgical therapies ever subjected to randomized clinical trials. Recent research has explored treating patients up to 24 h following the onset of stroke using advanced imaging techniques to select patients with brain tissue still at risk. These new findings suggest there exists a tissue clock rather than a time clock when selecting patients for therapy. Stroke systems throughout the world are now embracing endovascular stroke therapy. Improving regional stroke systems of care and expanding eligibility for patients are a major focus of current research.

Validation and iteration of CT perfusion defined malignant profile thresholds for acute ischemic stroke

BACKGROUND

Malignant profile computed tomography perfusion (CTP) lesions are associated with poor outcomes after administration of intravenous tissue-plasminogen activator (IV-tPA) for ischemic stroke.

AIMS

To determine whether published CTP-based lesion thresholds predictive of poor outcomes in a predominantly 8 cm of CTP anatomic coverage cohort would predict poor outcomes in an independent 4 cm of CTP anatomic coverage cohort and to generate optimized 4 cm CTP thresholds.

METHODS

Ischemic stroke patients with baseline CTP imaging with 4 cm of anatomic coverage before receiving IV-tPA at a single institution were retrospectively studied. Perfusion lesion time to maximum of tissue residue function (Tmax) and cerebral blood flow (CBF) volumes were determined using RAPID automated software. Fisher's exact tests assessed associations between lesion thresholds and outcomes. Receiver operating characteristic (ROC) curves generated optimized thresholds for 4 cm of CTP coverage.

RESULTS

Sixty-three patients were included. Poor outcomes were associated with published thresholds of Tmax >6 s > 103 mL, Tmax > 8 s > 86 mL, and Tmax > 10 s > 78 mL but not CBF core >53 mL. Thresholds optimized for 4 cm of CTP coverage and associated with poor outcomes were Tmax > 6 s > 100 mL, Tmax > 8 s > 65 mL, Tmax >10 s > 46 mL, and CBF core >39 mL.

CONCLUSIONS

We validated the ability of published CTP Tmax lesion volume thresholds to predict poor outcomes despite IV-tPA in an independent cohort using only 4 cm of CTP anatomical coverage. A CBF > 39 mL threshold, rather than the predominantly 8 cm CTP coverage derived CBF threshold of >53 mL, was associated with poor outcomes in this 4 cm CTP coverage cohort.

Abstract TMP72: Detection of a Novel Signal of Large Vessel Occlusion Stroke Using Cranial Accelerometry- The Headpulse

Introduction: Cranial accelerometry is used to detect cerebral vasospasm and concussion. We explored this technique in a cohort of code stroke patients to see if a signature could be identified to aid in the diagnosis of large vessel occlusion (LVO) stroke.

Methods: A military-grade 3-axis accelerometer was affixed to a headset. Accelerometer output and ECG was digitized at 1.6Khz. The resulting digitized signals we call the “Headpulse”. Three-minute recordings were performed immediately after CTA and/or immediately before and after attempted mechanical thrombectomy. The resulting waveforms were inspected by eye then subjected to supervised machine learning (MATLAB Classification Learner R2018a) to train a model using 5-fold cross validation.

Results: Of 42 code stroke subjects with recordings, 18 (43%) had LVO and 24 (57%) had normal CTAs. In patients without LVO, ECG-triggered waveforms followed a tightly similar time-course revealing that the Headpulse is highly coupled to the cardiac contraction (Figure A - small vessel stroke; Figure B - stroke mimic migraine). However, in LVO patients many recordings showed little correlation with the ECG (Figure 1 C). This abnormality we term “chaos” and parameterized it with 176 measures of trace-by-trace variation from the ECG-signal-averaged mean for machine learning model training. Selecting the best model, using biometric data only, we properly classified 15/18 LVOs and 18/24 non-LVO patients (p=0.0002, Fisher’s exact test). Headpulse waveforms following thrombectomy showed return of cardiac contraction correlation (Figures C and D).

Conclusions: Headpulse recordings reveal a unique signature in LVO patients during acute stroke. This lack of correlation of the Headpulse with cardiac contraction and later return of correlation likely reflects changes of cerebral blood flow and may provide a useful technique to triage stroke patients using a non-invasive device.

Abstract WP80: Association of Clot Burden Score and Thrombectomy 6 to 24 Hours After Stroke: Analysis of the DAWN Trial

Introduction: Clot burden score (CBS) is developed to evaluate anterior circulation ischemic stroke thrombus extent. Lower CBS is associated with worse functional outcome in an analysis of MR CLEAN trial without modifying the effect of mechanical thrombectomy within 6 hours after symptoms onset. An analysis of SWIFT PRIME trial showed that stent-retriever thrombectomy successfully recanalize regardless of CBS. However, thrombus that remains stagnant for longer period may be further compressed by the water-hammer effect of the systolic blood pressure, resulting in removal difficulty. We aim to explore relation of CBS with mechanical thrombectomy (MT) in the extended 6-24 hours of the DAWN trial.

Method: A blinded assessor evaluated CBS in all patients receiving CTA brain in the multicenter randomized DAWN trial for MT in acute large vessel occlusion last known well 6-24 hours (DWI or CTP Assessment with Clinical Mismatch in the Triage of Wake up and Late Presenting Strokes Undergoing Neurointervention). The cohort was divided into low CBS (0-4) and high CBS (5-10) groups. We used ordinal logistic regression for analysis of association with good outcome (mRS≤2), adjusted for significant baseline variables.

Results: 143 patients were included. Low CBS group consisted of 50 patients (29 received MT and 21 received medical management). High CBS group consisted of 93 patients (44 received MT and 49 received medical management). Baseline demographics were similar between groups. Low CBS group showed no difference in the odd of good outcome, adjusted OR 0.58 (0.3-1.14). Analysis of MT cases, Low CBS group showed a strong trend to higher procedure time (81.5±55.2 versus 56.4±35.3 min, p=0.07). There was no association of Low CBS and odds of good outcome (OR 0.9; 0.27-2.92), successful recanalization (OR 0.58; 0.18-1.89), and symptomatic intracranial hemorrhage (OR 1.67, 0.55-5.09).

Conclusion: Despite literature reporting worse outcome of anterior circulation ischemic stroke with low CBS, acute large vessel occlusion stroke with last known well 6-24 hours and low CBS treated with thrombectomy was feasible and not associated with worsen outcome compared to high CBS. However, a strong trend to higher procedure time is observed.

Abstract TMP68: Simple Neurological Exam Combined With Headpulse Accurately Predicts Large Vessel Occlusion Stroke

Introduction: Early prediction of whether or not a patient is having a large vessel occlusion (LVO) stroke could facilitate faster treatment through triage to an endovascular center. Clinical LVO stroke prediction scales achieve accuracies near 80%. We developed a non-invasive device to measure the Headpulse (imperceptible head movements due to the cardiac contraction detected by cranial accelerometry) and used this biometric data and a stroke scale to predict LVO.

Methods: Academic hospital emergency department and transfer code stroke patients had a 3-minute Headpulse recording after CTA and prior to thrombectomy when applicable. Intracranial hemorrhage patients were excluded. We quantified the variance of Headpulse recordings from one cardiac cycle to the next and used supervised machine learning (MATLAB Classification Learner R2018a) with 5-fold cross validation to train a model. This was repeated after adding the SAVE scale (1 point for each of Speech abnormality, asymmetric Arm weakness, Vision deficit, Eye deviation). Patients were classified as LVO if there was an occlusion of the ICA, M1, M2, vertebral, or basilar arteries on CTA or non-LVO if the CTA was normal or showed only more distal occlusion(s).

Results: 42 patients were included. Of 18 LVO patients there were 3 ICA, 1 basilar, 10 M1, and 4 M2 occlusions. Of 24 non-LVO patients there were 11 ischemic strokes, 2 TIAs, and 11 stroke mimics.

Adding SAVE to the training data resulted in a classification tree with 'asymmetric arm weakness' as the first node due to its high accuracy. Subsequent Headpulse nodes led to correct classification of all patients that would be false positives by clinical exam alone.

Conclusions: In a highly selected derivation cohort, clinical exam correctly classified LVO patients 93% of the time. Addition of a biometric derived from cranial accelerometry improved this accuracy. Validation in a representative code stroke cohort with intracranial hemorrhage patients is required.

Abstract WP27: Alteration in Clinical Outcome Between Discharge and Three Months After Mechanical Thrombectomy versus Medical Management in Late-Presenting Stroke Patients

Background: Mechanical thrombectomy in late-presenting stroke patients with a limited infarct core on CTP/DWI is highly effective. We aimed to evaluate the degree of disability at discharge as an indicator for functional impairment at one and three months after mechanical thrombectomy compared to medical management in these patients.

Methods: This study concerns a post-hoc analysis of the DAWN-trial population. Patients presenting 6-24h after symptom onset of an emergent large vessel occlusion with mismatch between symptom severity and infarct size on CTP/DWI, were randomized for medical management versus mechanical thrombectomy. We assessed the change in modified Rankin score (mRS) from discharge up to three months post-stroke for DAWN-patients treated with mechanical thrombectomy compared to those randomized to medical management. Kendall’s tau test was used to evaluate the correlation between the mRS at discharge, at 30 days, and at 90 days. Mixed models were used to explore the potential difference between treatment arms in the change of utility weighted mRS over time.

Results: Ninety-eight of 107 patients treated with mechanical thrombectomy and 89/99 controls survived at discharge and were included in the analysis. We found a strong correlation between the mRS at discharge, at 30 days, and at 90 days for both treatment arms with a tau varying from 0.52 to 0.72 for mechanical thrombectomy and 0.56 to 0.71 for medical management. All correlation coefficients were statistically significant (p < 0.0001). The utility weighted mRS after mechanical thrombectomy was consistently superior to medical management (p < 0.0001). Although there was a trend towards a stronger dispersion of the utility weighted mRS over time after mechanical thrombectomy, there was no statistically significant interaction effect between time and treatment arm (p 0.44).

Conclusion: The treatment effect of mechanical thrombectomy occurs early and further improvement over time is similar to that of medical management. The mRS at discharge is a robust indicator for functional status at one and three months post stroke and may therefore be used as an alternative measure for clinical outcome.

The Speech Arm Vision Eyes (SAVE) scale predicts large vessel occlusion stroke as well as more complicated scales

INTRODUCTION

The Speech Arm Vision Eyes (SAVE) scale, a 4-item clinical scale emphasizing binary scoring and avoidance of nuanced examination distinctions, predicts LVOs with similar characteristics as more complex scales.

METHODS

Receiver operating characteristic analyses of the prospective STOPStroke study assessed the ability of the SAVE scale and other published scales to predict LVO. We identified scale thresholds with positive likelihood ratios with 95% confidence intervals of ≥5.0 or negative likelihood ratios with 95% confidence intervals of ≤0.5.

RESULTS

735patients were studied. LVO prevalence was 33%. Area under the curve was 0.79 for SAVE, 0.82 for FAST-ED, 0.80 for mNIHSS and NIHSS, and lower for all other scales. SAVE=4, EMSA=6, mNIHSS≥10, NIHSS≥16, and RACE≥8 had positive likelihood ratios with 95% confidence intervals ≥5.0. SAVE≥2, CPSS≥2, C-STAT≥1, EMSA≥4, FAST-ED≥3, G-FAST≥3, mNIHSS≥6, NIHSS≥9, PASS≥1, RACE≥2, VAN=1, and 3I-SS≥1 had negative likelihood ratios with 95% confidence intervals ≤0.5.

CONCLUSIONS

SAVE=4 performed similarly to more complex scales at predicting LVO. Other simplified scales did not have thresholds with positive likelihood ratios with 95% confidence intervals ≥5.0. Validation is need in a prehospital cohort of patients with suspected stroke.

Abstract WMP15: Serial Aspects in the Dawn Trial: Infarct Evolution and Clinical Impact

Background: The impact of baseline ischemia on Aspects and evolution over 24 hours may be distinct in the late thrombectomy time window recently established by dawn. Aspects may enable practical triage of thrombectomy candidates more than 6 hours after onset.

Methods: The dawn Imaging Core Lab independently scored Aspects at baseline and 24 hours. Descriptive statistics characterized Aspects on CT or MRI at baseline and 24 hours, delineating serial ASPECTS change or infarct evolution over 24 hours and analyzing associations with clinical variables, treatment arm and clinical outcomes.

Results: 193 DAWN subjects (mean age 70.2 ± 13.7 yrs; 56% female; baseline NIHSS median 17 (14, 21) had core lab adjudicated Aspects at both baseline and 24 hours. Baseline Aspects was median 8.0 (3-10), with 89/193 (46.1%) between 0-7 and 104/193 (53.9%) between 8-10. 24-hour ASPECTS was median 6.0 (0-9), with serial ASPECTS change or infarct evolution of median -1, ranging from -8 to 0. Multivariate logistic regression showed age (OR 1.03 (yr) 95%CI (1.01-1.05), p=0.011) and male sex (OR 0.51 95%CI (0.30-0.86), p=0.012) predicted higher baseline ASPECTS. Higher 24-hour ASPECTS was predicted by endovascular treatment (OR 2.42 95%CI (1.42-4.12), p=0.001), baseline glucose < 150 mg/dL (OR 2.23 95%CI (1.19-4.18), p=0.012), lower baseline NIHSS (OR 0.92 95%CI (0.88-0.97), p=0.003) and age (OR 1.03 (yr) 95%CI (1.01-1.05), p=0.002). Good clinical outcome (day 90 mRS 0-2) was predicted by 24-hour ASPECTS (OR 1.50 95%CI (1.22-1.85), p<0.001). Dramatic infarct evolution (ASPECTS decrease ≥ 6) occurred in 15/193 (7.8%). Elevated baseline serum glucose (mg/dL) was a potent predictor of serial ASPECTS change of 4, 5, or 6 points (OR 1.01, all p<0.010). Serial ASPECTS change was dramatically influenced by treatment arm (p=0.004), including 0 ASPECTS change in 40/99 (40.4%) of the endovascular arm and only 18/94 (19.1%) of the medical arm.

Conclusions: DAWN subjects enrolled with small infarct cores in the late time window had a broad range of baseline ASPECTS. 24-hour ASPECTS, strikingly influenced by endovascular therapy, predicted good clinical outcomes. Infarct evolution on serial ASPECTS provides robust biomarker data for endovascular therapy up to 24 hours from onset.

Abstract 78: Time to Endovascular Treatment and Outcomes in the DAWN Trial

Introduction: It is well-established that, within 0-6 hours, the benefit of thrombectomy rapidly decays over time. The DAWN trial demonstrated that, in the presence of clinical-core mismatch (CCM), thrombectomy remains beneficial within 6-24 hours. We aim to assess the effect of time to randomization on outcomes in the DAWN.

Methods: We used traditional multivariate logistic regression controlling age and NIHSS at baseline adding an interaction between Trevo and Time last seen well and then generated the odds ratio of the interaction of Trevo and time at particular time points.

Results: Each 1-hour delay to treatment markedly impacted functional independence (OR,0.89 [95% CI 0.75 to 1.03]). Although the odds of functional independence at 90 days (mRS 0-2) with thrombectomy declined with longer time from last seen well (TLSW) to puncture, treatment benefit was observed through 24 hours : cOR at 8 hours, 6.8 (95% CI, 2.1 to 22.0), absolute risk difference (ARD) for mRS 0-2, 24.4%; cOR at 12 hours, 9.4 (95% CI, 4.1 to 21.6), ARD, 35.1%; cOR at 16 hours, 13.0 (95% CI, 4.1 to 41.3), ARD, 37.2%; cOR at 20 hours, 17.8 (95% CI, 2.9 to 110.4), ARD, 36.5%; cOR at 24 hours, 24.6 (95% CI, 1.9 to 322), ARD, 35.5% (Figure). Comparable analysis using time from symptoms first observed (TSFO) yielded similar results.

Conclusion: In patients selected based on CCM, treatment benefit persists all the way to 24 hours; however, both the chances of good outcome and the overall treatment effect continuously drop over time.

Abstract 106: Collateral Circulation in Thrombectomy for Stroke Beyond 6 Hours: Dawn Collaterals

Background: Collaterals govern the pace and severity of cerebral ischemia, distinguishing fast or slow progressors and corresponding therapeutic opportunities. The fate of sustained collateral perfusion or collateral failure is poorly characterized without arterial revascularization. We characterized the nature and impact of collaterals in the late time window for thrombectomy established in DAWN.

Methods: The DAWN Imaging Core Lab prospectively scored collateral grade on baseline CTA and DSA (endovascular arm only), blinded to all other data. CTA collaterals were graded with the Tan scale and DSA collaterals were scored by ASITN grade. Descriptive statistics characterized CTA collateral grade in all DAWN subjects and DSA collaterals in the endovascular arm. The relationship between collateral grade and day 90 outcomes was separately analyzed for each treatment arm.

Results: Collateral circulation to the ischemic territory was evaluated on CTA (n=144; median 2, 0-3) and DSA (n=57; median 2, 1-4) before thrombectomy in 161 DAWN subjects (mean age 69.8 ± 13.6 years; 55.3% women; 91 endovascular therapy, 70 control). CTA revealed a broad range of collaterals (grade 3=100%, n=64; 2=50-99%, n=45; 1=0-49%, n=31; 0=0%, n=4). DSA also showed a diverse range of collateral grades (grade 4, n=4; 3, n=22; 2, n=27; 1, n=4). Across treatment arms, baseline demographics, clinical variables except AF (41.6% endovascular vs. 25.0%, p=0.04) and CTA collateral grades were balanced. More robust CTA collateral grade was linked with lower baseline NIHSS (r=-0.25; p=0.003), smaller core infarct volumes (r=-0.36, p<0.001) and better day 90 mRS 0-2 clinical outcomes (r=0.20, p=0.019), but was unrelated to time from symptom onset or last known well to thrombectomy. Higher DSA collateral grade was linked with lower baseline NIHSS (r=-0.32; p=0.015), but sample size limited other potential associations. Interestingly, collateral grades on CTA and DSA were highly correlated (r=0.88, p<0.001).

Conclusions: DAWN subjects enrolled at 6-24 hours after onset with small infarct cores had a wide range of collateral grades on both CTA and DSA. In this late time window, better collaterals manifest milder stroke severity at baseline, smaller infarct cores and better clinical outcomes.

Abstract TMP63: Simplified SAVE Large Vessel Occlusion Prediction Scale Performs Similarly to More Complex Scales

Introduction: Prehospital Large Vessel Occlusion (LVO) prediction scales report accuracies near 80% but vary in complexity and exam items tested. NIHSS subscores of Best Gaze, Motor Arm, Visual fields, and Best Language and/or Extinction are most predictive of ICA, M1, or M2 LVOs. Complex scoring and exam distinctions could limit the adoption of prehospital LVO scales.

Hypothesis: We hypothesized that SAVE, a 4 item clinical scale with absent/present scoring and avoidance of nuanced exam distinctions, would predict LVOs as well as the 5 item and 9 point Field Assessment Stroke Triage for Emergency Destination (FAST-ED) scale.

Methods: Retrospective analysis of the prospective Screening Technology and Outcomes Project in Stroke (STOPStroke) Study included 735 patients with suspected acute ischemic stroke or TIA evaluated in emergency departments with NIHSS scores and computed tomography angiography. Receiver operating characteristic analyses assessed the ability of the 4 point SAVE scale to predict the presence of ICA, M1, M2, or Basilar artery LVOs. The SAVE scale assigns 1 point for any NIHSS abnormalities in Speech (Best Language and/or Dysarthria), Motor Arm, Visual fields, or Eye deviation (Best Gaze). The results were compared to the published FAST-ED scale, which was derived from the same STOPStroke cohort and performs similarly to other published scales.

Results: The prevalence of ICA, M1, M2, or Basilar artery LVOs was 31%. The SAVE scale area under the curve (AUC) was 0.79 and the FAST-ED scale AUC was reported as 0.81. SAVE ≥1 and ≥2 are equivalent to FAST-ED ≥1 and ≥2. SAVE ≥3 is equivalent to FAST-ED ≥4. SAVE ≥4 is equivalent to FAST-ED ≥6.

Conclusions: The SAVE scale performed similarly to the FAST-ED scale at predicting ICA, M1, M2, or Basilar artery LVOs. The SAVE scale focuses on 4 items with present/absent scoring and avoids the nuances of aphasia and neglect to reduce the complexity of prehospital LVO prediction. Prospective prehospital validation is needed.

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 .).

Periprocedural heparin use in acute ischemic stroke endovascular therapy: the TREVO 2 trial

BACKGROUND

The use of periprocedural heparin has previously been reported to be safe and potentially beneficial during thrombectomy with older generation devices. We aimed to evaluate the safety and clinical outcomes of heparin use in the stent retriever era.

METHODS

A post hoc analysis of the TREVO 2 trial was performed comparing baseline characteristics and clinical outcomes between patients who received (HEP+) and those who did not receive periprocedural heparin (HEP-) while undergoing MERCI or TREVO clot retrieval.

RESULTS

Of 173 patients, 58 (34%) received periprocedural heparin including 40 who received one preprocedural bolus (median 3000 units). Baseline characteristics among HEP+ and HEP- patients were similar except HEP+ patients had a lower NIH Stroke Scale (NIHSS) score (17 vs 19; p=0.04), lower IV tissue plasminogen activator use (38% vs 64%; p<0.01), and a higher median ASPECTS score (8.0 vs 7.0; p=0.02). HEP+ patients were more likely to have vertebrobasilar and middle cerebral artery (MCA)-M1 occlusions but less likely to have internal carotid artery and MCA-M2 occlusions (p=0.04). Time from symptom onset to puncture was similar in the two groups while procedure duration was longer in HEP+ patients (99 vs 83 min; p<0.01). Thrombolysis In Cerebral Infarction (TICI) 2b-3 reperfusion rates, embolization to unaffected territories, access site complications, and intracranial hemorrhages were similar between the groups. In multivariable logistic regression, a good outcome (90-day modified Rankin Scale score 0-2) was independently associated with heparin bolus use (OR 5.30; 95% CI 1.70 to 16.48), TICI 2b-3 reperfusion (OR 6.56; 95% CI 2.29 to 18.83), stent retriever use (OR 3.54; 95% CI 1.38 to 9.03) and inversely associated with intubation (OR 0.10; 95% CI 0.03 to 0.33), diabetes (OR 0.11; 95% CI 0.03 to 0.39), NIHSS (OR 0.84; 95% CI 0.75 to 0.93), time from symptom onset to puncture (OR 0.64; 95% CI 0.45 to 0.89), and heart failure (OR 0.23; 95% CI 0.06 to 0.83).

CONCLUSIONS

The use of periprocedural heparin in stent retriever thrombectomy is associated with a good clinical outcome at 90 days and similar rates of symptomatic intracranial hemorrhage. Further studies are warranted.

CLINICAL TRIAL REGISTRATION

URL:http://www.clinicaltrials.gov. Unique identifier: NCT01270867;Post-results.

Endovascular Stroke Therapy

Acute ischemic stroke therapy has rapidly evolved over the past two decades. Recently, a paradigm shift has occurred in the treatment of acute ischemic stroke due to large vessel occlusion with the publication of several randomized trials proving that mechanical thrombectomy with stent retriever devices improves clinical outcome in comparison to intravenous thrombolysis. Furthermore, pooled data from the clinical trials suggest that mechanical thrombectomy can improve outcome in a broad range of patients, and that the sooner the intervention can be performed, the greater the benefit. Delays in endovascular stroke therapy can occur during multiple time points during a patient's encounter, and these time delays are associated with worse outcomes. This association emphasizes the importance of enhancing speed-of-care processes in patients undergoing endovascular reperfusion. Efforts to reduce time delays in endovascular stroke treatment can be achieved by reflecting on the health care initiatives that took place for the treatment of acute myocardial infarction almost 20 years ago. The ideal system of care to reduce delays in endovascular stroke therapy will likely include rapid transport of all eligible patients directly to the angiography suite to bypass the inefficiencies of workflow during the early inhospital setting. These strategies will undoubtedly take time to implement, as they require further research, infrastructure funding, and policy changes at local, regional, and national levels.

Emergency Neurologic Life Support (ENLS): Evolution of Management in the First Hour of a Neurological Emergency

Emergency neurological life support (ENLS) is an educational program designed to provide users advisory instruction regarding management for the first few hours of a neurological emergency. The content of the course is divided into 14 modules, each addressing a distinct category of neurological injury. The course is appropriate for practitioners and providers from various backgrounds who work in environments of variable medical complexity. The focus of ENLS is centered on a standardized treatment algorithm, checklists to guide early patient care, and a structured format for communication of findings and concerns to other healthcare professionals. Certification and training in ENLS is hosted by the Neurocritical Care Society. This document introduces the concept of ENLS and describes the revisions that constitute this second version.

Field Assessment Stroke Triage for Emergency Destination: A Simple and Accurate Prehospital Scale to Detect Large Vessel Occlusion Strokes

BACKGROUND AND PURPOSE

Patients with large vessel occlusion strokes (LVOS) may be better served by direct transfer to endovascular capable centers avoiding hazardous delays between primary and comprehensive stroke centers. However, accurate stroke field triage remains challenging. We aimed to develop a simple field scale to identify LVOS.

METHODS

The Field Assessment Stroke Triage for Emergency Destination (FAST-ED) scale was based on items of the National Institutes of Health Stroke Scale (NIHSS) with higher predictive value for LVOS and tested in the Screening Technology and Outcomes Project in Stroke (STOPStroke) cohort, in which patients underwent computed tomographic angiography within the first 24 hours of stroke onset. LVOS were defined by total occlusions involving the intracranial internal carotid artery, middle cerebral artery-M1, middle cerebral artery-2, or basilar arteries. Patients with partial, bihemispheric, and anterior+posterior circulation occlusions were excluded. Receiver operating characteristic curve, sensitivity, specificity, positive predictive value, and negative predictive value of FAST-ED were compared with the NIHSS, Rapid Arterial Occlusion Evaluation (RACE) scale, and Cincinnati Prehospital Stroke Severity (CPSS) scale.

RESULTS

LVO was detected in 240 of the 727 qualifying patients (33%). FAST-ED had comparable accuracy to predict LVO to the NIHSS and higher accuracy than RACE and CPSS (area under the receiver operating characteristic curve: FAST-ED=0.81 as reference; NIHSS=0.80, P=0.28; RACE=0.77, P=0.02; and CPSS=0.75, P=0.002). A FAST-ED ≥4 had sensitivity of 0.60, specificity of 0.89, positive predictive value of 0.72, and negative predictive value of 0.82 versus RACE ≥5 of 0.55, 0.87, 0.68, and 0.79, and CPSS ≥2 of 0.56, 0.85, 0.65, and 0.78, respectively.

CONCLUSIONS

FAST-ED is a simple scale that if successfully validated in the field, it may be used by medical emergency professionals to identify LVOS in the prehospital setting enabling rapid triage of patients.

A low-cost, tablet-based option for prehospital neurologic assessment: The iTREAT Study

OBJECTIVES

In this 2-center study, we assessed the technical feasibility and reliability of a low cost, tablet-based mobile telestroke option for ambulance transport and hypothesized that the NIH Stroke Scale (NIHSS) could be performed with similar reliability between remote and bedside examinations.

METHODS

We piloted our mobile telemedicine system in 2 geographic regions, central Virginia and the San Francisco Bay Area, utilizing commercial cellular networks for videoconferencing transmission. Standardized patients portrayed scripted stroke scenarios during ambulance transport and were evaluated by independent raters comparing bedside to remote mobile telestroke assessments. We used a mixed-effects regression model to determine intraclass correlation of the NIHSS between bedside and remote examinations (95% confidence interval).

RESULTS

We conducted 27 ambulance runs at both sites and successfully completed the NIHSS for all prehospital assessments without prohibitive technical interruption. The mean difference between bedside (face-to-face) and remote (video) NIHSS scores was 0.25 (1.00 to -0.50). Overall, correlation of the NIHSS between bedside and mobile telestroke assessments was 0.96 (0.92-0.98). In the mixed-effects regression model, there were no statistically significant differences accounting for method of evaluation or differences between sites.

CONCLUSIONS

Utilizing a low-cost, tablet-based platform and commercial cellular networks, we can reliably perform prehospital neurologic assessments in both rural and urban settings. Further research is needed to establish the reliability and validity of prehospital mobile telestroke assessment in live patients presenting with acute neurologic symptoms.

Abstract WMP9: National Trends in the Use of Endovascular Stroke Treatment at Academic Medical Centers (2009-15)

Objective: To characterize temporal trends in the use of endovascular treatment (EVT) for acute ischemic stroke at academic medical centers in response to recent clinical trials.

Background: Although endovascular devices for stroke were first cleared for marketing in 2004, initial clinical trials in 2013 failed to demonstrate efficacy and subsequent clinical trials beginning in 2014 were strongly positive. The impact of these data on practice patterns at academic medical centers, which perform most EVTs, is unknown.

Methods: We identified all acute ischemic stroke hospitalizations at academic medical centers that were members in the University HealthSystem Consortium from October 2009 to July 2015 using International Classification of Disease, 9th revision codes 433.x1, 434.x1, and 436 for stroke and procedure code 39.74 for EVT. We compiled quarterly data on the number and proportion of stroke hospitalizations using EVT and we used segmented log-linear regression to identify temporal trends and to evaluate changes in trends at prespecified time points corresponding to the quarter in which pivotal trials were first reported.

Results: From 2009-15, we identified 357,973 acute ischemic stroke hospitalizations at 161 medical centers. The proportion of stroke hospitalizations using EVT was 1.5% in 2009 and grew by 25% a year (95% CI 21% to 29%) to reach 3.1% in 2013. After negative results from the initial trials were reported in 2013, EVT use hovered between 2.5% and 2.7% (1% relative change per year; 95% CI -9% to +8%; p=0.004 for change in trend) until 2014 when the first positive trials were reported and EVT use jumped at a growth rate of 151% per year (95% CI 101% to 212%; p<0.001 for change in trend) to reach fully 4.7% of all stroke hospitalizations by 2015.

Conclusion: The previously steady growth in EVT flattened in 2013, coincident with the initially negative results from clinical trials, but has dramatically increased since positive trials were first reported in 2014.

Abstract 155: Proving CT Angiography of Collaterals Prior to Endovascular Therapy: TREVO & TREVO 2

Background: CT angiography (CTA) has become the predominant mode of imaging selection prior to endovascular stroke therapy. The added value of CTA collaterals beyond ASPECTS and validation with digital subtraction angiography (DSA) remain unaddressed. We determined the impact and validity of CTA collateral grade with DSA in the multicenter TREVO and TREVO 2 trials.

Methods: Pooled analyses of the TREVO and TREVO 2 CTA dataset prior to endovascular therapy were conducted. CTA collaterals were scored (0-20) with the regional leptomeningeal collateral score (rLMC) and directly compared with the ASITN/SIR (0-4) collateral grade. Statistical analyses included descriptive statistics and Spearman correlation analysis among CTA, DSA collaterals and ASPECTS. Logistic regression analysis was used to model 90-day good outcome and revascularization success.

Results: CTA and DSA collaterals were compared in 116 subjects with anterior circulation occlusions. ASPECTS was median 8 (range 3-10; 49% 0-7 versus 51% 8-10), with CTA collaterals on rLMC score of median 16 (range 4-20) and DSA collaterals median 2 (range 1-4; 13% grade 1, 50% grade 2, 26% grade 3 and 11% grade 4). ASPECTS exhibited only moderate correlation with collaterals at CTA (ρ=0.35, p<0.001) and DSA (ρ=0.41, p<0.001). Similarly, only moderate correlation was noted between CTA collaterals and DSA (ρ=0.43, p<0.001). Baseline ASPECTS better predicted (OR 1.50 95%CI [1.08-2.09], p=0.017) good clinical outcome (90-day mRS 0-2) compared to CTA collaterals (OR 1.10 95%CI [1.00-1.22], p=0.058), whereas DSA collaterals were most predictive (OR 1.99 95%CI [1.20-3.29], p=0.008). Multivariate logistic regression revealed DSA collateral grade 3 or greater as paramount for achieving good outcomes (OR 3.00 95%CI [1.31-6.89], p=0.01).

Conclusions: Single-phase CTA collateral scoring prior to endovascular therapy provides marginal value beyond ASPECTS and limited correlation with the extent of collaterals on DSA. CTA of collaterals may perform differently at very high ASPECTS or with further development of imaging acquisition or post-processing techniques.

Improved Ischemic Stroke Outcome Prediction Using Model Estimation of Outcome Probability: The THRIVE-c Calculation

Background and purpose

The Totaled Health Risks in Vascular Events (THRIVE) score is a previously validated ischemic stroke outcome prediction tool. Although simplified scoring systems like the THRIVE score facilitate ease-of-use, when computers or devices are available at the point of care, a more accurate and patient-specific estimation of outcome probability should be possible by computing the logistic equation with patient-specific continuous variables.

Methods

We used data from 12 207 subjects from the Virtual International Stroke Trials Archive and the Safe Implementation of Thrombolysis in Stroke – Monitoring Study to develop and validate the performance of a model-derived estimation of outcome probability, the THRIVE-c calculation. Models were built with logistic regression using the underlying predictors from the THRIVE score: age, National Institutes of Health Stroke Scale score, and the Chronic Disease Scale (presence of hypertension, diabetes mellitus, or atrial fibrillation). Receiver operator characteristics analysis was used to assess model performance and compare the THRIVE-c model to the traditional THRIVE score, using a two-tailed Chi-squared test.

Results

The THRIVE-c model performed similarly in the randomly chosen development cohort ( n = 6194, area under the curve = 0·786, 95% confidence interval 0·774–0·798) and validation cohort ( n = 6013, area under the curve = 0·784, 95% confidence interval 0·772–0·796) ( P = 0·79). Similar performance was also seen in two separate external validation cohorts. The THRIVE-c model (area under the curve = 0·785, 95% confidence interval 0·777–0·793) had superior performance when compared with the traditional THRIVE score (area under the curve = 0·746, 95% confidence interval 0·737–0·755) ( P < 0·001).

Conclusion

By computing the logistic equation with patientspecific continuous variables in the THRIVE-c calculation, outcomes at the individual patient level are more accurately estimated. Given the widespread availability of computers and devices at the point of care, such calculations can be easily performed with a simple user interface.

Carotid I's, L's and T's: collaterals shape the outcome of intracranial carotid occlusion in acute ischemic stroke

BACKGROUND

Collaterals may affect revascularization, ischemic severity, and clinical outcomes in acute stroke owing to internal carotid artery (ICA) occlusion.

OBJECTIVE

To examine the hypothesis that morphology of occlusive thrombus and collateral flow patterns may influence the outcome of ICA occlusions after mechanical thrombectomy.

METHODS

Pooled analyses of ICA occlusions in the MERCI and Multi-MERCI trials employed central angiography review readings to categorize lesions as I, L, or T clots and functional lesions based on collateral flow patterns. Demographic variables, procedural details, and clinical outcomes were compared across ICA lesion types.

RESULTS

A total of 72 subjects (mean age 67 years (SD 16), 51% female, median National Institutes of Health Stroke Scale 20 (range 8-35)) were included, with 90-day modified Rankin score ≤2 in 28% and 51% mortality. Clots were categorized as an I lesion in 9/72 (12.5%), L lesion in 12/72 (16.7%), and T lesion in 51/72 (70.8%). Based on collateral flow patterns, cases were categorized as having a functional I lesion in 7/72 (9.7%), functional L in 38/72 (52.8%), and functional T in only 27/72 (37.5%). Multivariate analyses showed that a functional T lesion, with insufficient collateral flow to ipsilateral anterior cerebral arteries via the contralateral ICA, was a strong predictor of both revascularization success and subsequent clinical outcomes.

CONCLUSIONS

Collateral flow patterns distinguish the nature and impact of ICA occlusions on expected revascularization and subsequent clinical outcomes in acute ischemic stroke. The nomenclature of terminal ICA occlusions introduced here (carotid I's, L's, and T's) may enhance future endovascular trials targeting such proximal occlusions.

TRIAL REGISTRATION NUMBER

NCT00318071 (http://clinicaltrials.gov). MERCI was not registered because enrollment began before July 1, 2005.

Effect of a balloon-expandable intracranial stent vs medical therapy on risk of stroke in patients with symptomatic intracranial stenosis: the VISSIT randomized clinical trial

IMPORTANCE

Intracranial stenosis is one of the most common etiologies of stroke. To our knowledge, no randomized clinical trials have compared balloon-expandable stent treatment with medical therapy in symptomatic intracranial arterial stenosis.

OBJECTIVE

To evaluate the efficacy and safety of the balloon-expandable stent plus medical therapy vs medical therapy alone in patients with symptomatic intracranial stenosis (≥70%).

DESIGN, SETTING, AND PATIENTS

VISSIT (the Vitesse Intracranial Stent Study for Ischemic Stroke Therapy) trial is an international, multicenter, 1:1 randomized, parallel group trial that enrolled patients from 27 sites (January 2009-June 2012) with last follow-up in May 2013.

INTERVENTIONS

Patients (N = 112) were randomized to receive balloon-expandable stent plus medical therapy (stent group; n = 59) or medical therapy alone (medical group; n = 53).

PRIMARY OUTCOME MEASURE

a composite of stroke in the same territory within 12 months of randomization or hard transient ischemic attack (TIA) in the same territory day 2 through month 12 postrandomization. A hard TIA was defined as a transient episode of neurological dysfunction caused by focal brain or retinal ischemia lasting at least 10 minutes but resolving within 24 hours. Primary safety measure: a composite of any stroke, death, or intracranial hemorrhage within 30 days of randomization and any hard TIA between days 2 and 30 of randomization. Disability was measured with the modified Rankin Scale and general health status with the EuroQol-5D, both through month 12.

RESULTS

Enrollment was halted by the sponsor after negative results from another trial prompted an early analysis of outcomes, which suggested futility after 112 patients of a planned sample size of 250 were enrolled. The 30-day primary safety end point occurred in more patients in the stent group (14/58; 24.1% [95% CI, 13.9%-37.2%]) vs the medical group (5/53; 9.4% [95% CI, 3.1%-20.7%]) (P = .05). Intracranial hemorrhage within 30 days occurred in more patients in the stent group (5/58; 8.6% [95% CI, 2.9%-19.0%]) vs none in the medical group (95% CI, 0%-5.5%) (P = .06). The 1-year primary outcome of stroke or hard TIA occurred in more patients in the stent group (21/58; 36.2% [95% CI, 24.0-49.9]) vs the medical group (8/53; 15.1% [95% CI, 6.7-27.6]) (P = .02). Worsening of baseline disability score (modified Rankin Scale) occurred in more patients in the stent group (14/58; 24.1% [95% CI, 13.9%-37.2%]) vs the medical group (6/53; 11.3% [95% CI, 4.3%-23.0%]) (P = .09).The EuroQol-5D showed no difference in any of the 5 dimensions between groups at 12-month follow-up.

CONCLUSIONS AND RELEVANCE

Among patients with symptomatic intracranial arterial stenosis, the use of a balloon-expandable stent compared with medical therapy resulted in an increased 12-month risk of added stroke or TIA in the same territory, and increased 30-day risk of any stroke or TIA. These findings do not support the use of a balloon-expandable stent for patients with symptomatic intracranial arterial stenosis.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00816166.

A quality assurance initiative targeting radiation exposure to neuroscience patients in the intensive care unit

BACKGROUND

Patients admitted to an intensive care unit (ICU) with a primary neurologic disorder often receive multiple radiation-based diagnostic studies of the head and neck. Although radiation exposure puts them at risk of intracranial and neck tumors, the amount of radiation received is largely unknown.

METHODS

We sought to accurately collect cumulative radiation exposure data from radiation-based studies in a retrospective cohort of patients admitted to the neuroscience ICU (NICU) at a single institution. Radiation doses of studies were converted to estimated effective doses in mSv via literature-published formulas. To impact ordering practices, we piloted an educational initiative on patient radiation exposure to a cohort of physicians caring for patients with a diagnosis of acute subarachnoid hemorrhage. Patients were randomized to have radiation exposure data posted at the bedside for physician viewing.

RESULTS

We identified 641 patients from July 2010 to March 2011 who had received at least 1 computed tomography-based study of the head. Patients received on average 18.4 mSv of radiation from head and neck imaging. Patients with subarachnoid hemorrhage received the highest average levels of radiation exposure (37.1 mSv). Attributable risk of carcinogenesis was estimated to be low. A pilot educational initiative did not reduce the total estimated effective dose per patient.

CONCLUSIONS

Accurate reporting of estimated effective doses for NICU patients is feasible and can be provided to ordering physicians to assist with clinical decision making and potentially lower exposure risk. Further strategies are needed to reduce unnecessary radiation exposure at the physician ordering level.

The THRIVE Score Predicts Symptomatic Intracerebral Hemorrhage after Intravenous tPA Administration in SITS-MOST

Background

The Totaled Health Risks in Vascular Events (THRIVE) score is a clinical prediction score that predicts ischemic stroke outcomes in patients receiving intravenous tissue plasminogen activator, endovascular stroke treatment, or no acute therapy. We have previously found an association between THRIVE and risk of post-tissue plasminogen activator symptomatic intracranial hemorrhage in the National Institute of Neurological Disorders and Stroke (NINDS) tissue plasminogen activator trial and risk of radiographic hemorrhage in Virtual International Stroke Trials Archive.

Aims

The study aims to validate the relationship between THRIVE and symptomatic intracranial hemorrhage among tissue plasminogen activator-treated patients in the large Safe Implementation of Thrombolysis in Stroke – Monitoring Study (SITS-MOST).

Methods

This is a retrospective analysis of the prospective SITS-MOST to examine the relationship between THRIVE and symptomatic intracranial hemorrhage after tissue plasminogen activator treatment. Symptomatic intracranial hemorrhage after tissue plasminogen activator was defined according to each of three standard definitions: the NINDS, European Cooperative Acute Stroke Study (ECASS), and Safe Implementation of Thrombolysis in Stroke (SITS) criteria. Multivariable logistic regression was used to confirm the relationship of THRIVE and individual THRIVE components with the risk of symptomatic intracranial hemorrhage and to examine the relationship of THRIVE, symptomatic intracranial hemorrhage, and functional outcome.

Results

The odds ratio for symptomatic intracranial hemorrhage at each increased level of THRIVE score is 1·34 (95% CI 1·27 to 1·41, P < 0·001) for symptomatic intracranial hemorrhage by NINDS criteria, 1·36 (95% CI 1·27 to 1·46, P < 0·001) for symptomatic intracranial hemorrhage by ECASS criteria, and 1·21 (95% CI 1·09 to 1·36, P < 0·001) for symptomatic intracranial hemorrhage by SITS criteria. In receiver-operator characteristics analysis, the C-statistic for THRIVE prediction of symptomatic intracranial hemorrhage was 0·65 (95% CI 0·62 to 0·67) for symptomatic intracranial hemorrhage by NINDS criteria, 0·66 (95% CI 0·63 to 0·69) for symptomatic intracranial hemorrhage by ECASS criteria, and 0·61 (95% CI 0·56 to 0·66) for symptomatic intracranial hemorrhage by SITS criteria. Each component of the THRIVE score predicts the risk of symptomatic intracranial hemorrhage, with independent impact of each component in multivariable analysis.

Conclusions

The THRIVE score predicts the risk of symptomatic intracranial hemorrhage after intravenous tissue plasminogen activator administration. This external validation of the relationship between THRIVE and symptomatic intracranial hemorrhage in a prospective study further strengthens the role of the THRIVE score in the prediction of poststroke outcomes.

Predictors of functional dependence despite successful revascularization in large-vessel occlusion strokes

BACKGROUND AND PURPOSE

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

METHODS

We analyzed the pooled data from the Multi Mechanical Embolus Removal in Cerebral Ischemia (MERCI), Thrombectomy Revascularization of Large Vessel Occlusions in Acute Ischemic Stroke (TREVO), and TREVO 2 trials. Successful revascularization was defined as thrombolysis in cerebral infarction score 2b or 3. Functional dependence was defined as a score of 3 to 6 on the modified Rankin Scale at 3 months. We assessed relationship of demographic, clinical, angiographic characteristics, and hemorrhage with functional dependence despite successful revascularization.

RESULTS

Two hundred and twenty-eight patients with successful revascularization had clinical outcome follow-up. The rates of functional dependence with endovascular success were 48.6% for Trevo thrombectomy and 58.0% for Merci thrombectomy. Age (odds ratio, 1.04; 95% confidence interval, 1.02-1.06 per 1-year increase), National Institutes of Health Stroke Scale score (odds ratio, 1.08; 95% confidence interval, 1.02-1.15 per 1-point increase), and symptom onset to endovascular treatment time (odds ratio, 1.11; 95% confidence interval, 1.01-1.22 per 30-minute delay) were predictors of functional dependence despite successful revascularization. Symptom onset to reperfusion time beyond 5 hours was associated with functional dependence. All subjects with symptomatic intracranial hemorrhage had functional dependence.

CONCLUSIONS

One half of patients with successful mechanical thrombectomy do not have good outcomes. Age, severe neurological deficits, and delayed endovascular treatment were associated with functional dependence despite successful revascularization. Our data support efforts to minimize delays to endovascular therapy in patients with acute ischemic stroke to improve outcomes.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00318071, NCT01088672, and NCT01270867.

Setting priorities for stroke care and research

Recent publications describing the sobering global increase in stroke mortality and global life years lost due to stroke despite improvements in developed countries have drawn focus on the severe impact of stroke in the developing world. At the same time, three recent interventional trials that failed to demonstrate an important role for catheter-based therapies in acute stroke have called into question this expensive use of technology. Coupling all of this new data leads to the natural conclusion that a focus on stroke prevention for the developing world, and for the poor in developed countries, should be where we set our priorities for the foreseeable future.

Symptom differences and pretreatment asymptomatic interval affect outcomes of stenting for intracranial atherosclerotic disease

BACKGROUND AND PURPOSE

Different types of symptomatic intracranial stenosis may respond differently to interventional therapy. We investigated symptomatic and pathophysiologic factors that may influence clinical outcomes of patients with intracranial atherosclerotic disease who were treated with stents.

MATERIALS AND METHODS

A retrospective analysis was performed of patients treated with stents for intracranial atherosclerosis at 4 centers. Patient demographics and comorbidities, lesion features, treatment features, and preprocedural and postprocedural functional status were noted. χ(2) univariate and multivariate logistic regression analysis was performed to assess technical results and clinical outcomes.

RESULTS

One hundred forty-two lesions in 131 patients were analyzed. Lesions causing hypoperfusion ischemic symptoms were associated with fewer strokes by last contact [χ(2) (1, n = 63) = 5.41, P = .019]. Nonhypoperfusion lesions causing symptoms during the 14 days before treatment had more strokes by last contact [χ(2) (1, n = 136), 4.21, P = .047]. Patients treated with stents designed for intracranial deployment were more likely to have had a stroke by last contact (OR, 4.63; P = .032), and patients treated with percutaneous balloon angioplasty in addition to deployment of a self-expanding stent were less likely to be stroke free at point of last contact (OR, 0.60; P = .034).

CONCLUSIONS

More favorable outcomes may occur after stent placement for lesions causing hypoperfusion symptoms and when delaying stent placement 7-14 days after most recent symptoms for lesions suspected to cause embolic disease or perforator ischemia. Angioplasty performed in addition to self-expanding stent deployment may lead to worse outcomes, as may use of self-expanding stents rather than balloon-mounted stents.

Abstract 3: Collaterals, Not Clots! CT Angiography Predictors of Recanalization, Reperfusion and Clinical Outcomes After Thrombectomy in Pooled Analyses of TREVO EU and TREVO2

Background: CTA is often used to define clot location prior to endovascular therapy yet systematic evaluation may reveal many details about underlying pathophysiology. We tested a battery of CTA measures to identify optimal predictors of response to thrombectomy.

Methods: CTA datasets of anterior circulation strokes in TREVO EU and TREVO2 with available source images were reconstructed into 3D-curved and 2D-orthogonal maximum-intensity projections by the core lab. Occlusion site, clot length and volume, clot burden score (CBS) and regional leptomeningeal collateral score (rLMC) were scored on CTA. Hyperdense vessels, Hounsfield Unit (HU) indices and location of hyperdensity relative to CTA occlusion site were noted on noncontrast CT.

Results: 111 cases (mean age 68.0 ± 13.8 years; 58.6% women; median baseline NIHSS 18 (8-28)) were analyzed. CTA occlusions were 68.5% M1, 22.5% M2, and 9.0% ICA. CTA clot volumes were mean 49.3 ± 36.3 mm 3 with mean CBS 6.7 ± 1.8 and mean rLMC 15.3 ± 4.2. Noncontrast hyperdensity was noted at M1 in 44.1%, M2 in 27.0%, and ICA 8.1%, with ipsilateral:contralateral HU indices of mean 1.3 ± 0.2. Noncontrast CT hyperdensity relative to CTA opacification revealed hyperdensity proximal to occlusions in 2.7%, just past occlusion in 55.0%, and distal to clot end in 6.2%. Only better collaterals on rLMC predicted AOL 2-3 recanalization (OR 1.26, p=0.058) in multivariate analyses and distal hyperdensity (OR 0.11, p=0.037) predicted worse recanalization. Similarly, only rLMC predicted TICI 2b-3 reperfusion (OR 1.27, p=0.004) and distal hyperdensity (OR 0.12, p=0.071) predicted worse reperfusion. Clots (CBS) and collaterals (rLMC) were moderately correlated with each other (0.44 Spearman) in multivariate models of good clinical outcome (mRS 0-2) at day 90, yet clots were significant only when removing collaterals.

Conclusions: Collaterals, not clots, are the best CTA predictors of outcomes after thrombectomy. Worse outcomes with hyperdensity distal to clots on CTA likely reflect stasis due to poor retrograde collaterals.

Abstract W MP9: Early Reperfusion with a Stentriever Device: A First Step to Superior Outcomes in TREVO2

Background: TREVO2 showed better outcomes after thrombectomy with the Trevo stentriever compared to Merci. We studied the impact of early reperfusion up to the first pass to explore the impact of device deployment on subsequent outcomes.

Methods: Reperfusion during stentriever deployment and after the first pass in both arms (Merci and Trevo) of TREVO2 was quantified by cerebral blood volume (CBV) delivered to the downstream territory using perfusion angiography (perfAngio) software. Automatic, normalized extraction of CBV distal to anterior circulation occlusions was obtained from AP projections during arterial phase. CBV during deployment, after the first pass and sum of CBV up to the first pass (Σ CBV) were analyzed with respect to angiographic and clinical outcomes.

Results: CBV was measured from DSA in 83 (34 Trevo, 49 Merci) occlusions in TREVO2. Clinical variables of this cohort were similar between device arms and with respect to others in the trial. During stentriever deployment, 29/34 cases demonstrated delivery of blood volume to downstream territory, averaging about 10% of the amount delivered after the first pass. Change in CBV from deployment to the first pass in 26/29 cases showed a further increase in 15 and decrease in 11, with re-occlusion in 4. CBV only after the first pass did not differ between Merci and Trevo (p=NS). CBV after first pass (p=0.06) and Σ CBV (p=0.03) both predict successful revascularization and demonstrate a moderate correlation with the time to sustained TICI 2a flow. Logistic regression analysis revealed that Σ CBV is a predictor of good clinical outcome (mRS 0-2) at day 90 (p=0.08) and use of Trevo further impacts outcome.

Conclusions: Stentriever deployment achieves delivery of blood volume to the ischemic bed downstream. The amount of CBV delivered up to the first pass influences revascularization and good clinical outcomes.

Abstract T P356: Predictors of Depression 6 Months After Aneurysmal Subarachnoid Hemorrhage

Background: Functional outcome is of increasing importance among survivors of aneurysmal subarachnoid hemorrhage (SAH). Depression is commonly reported after stroke and may play a significant role in functional recovery after SAH. Our goal was to determine the prevalence and predictors of depression among survivors of SAH at 6 months.

Methods: Six-month follow up data was analyzed from a cohort study of SAH patients at a tertiary care center. With IRB approval and consent, patients completed serial 6-month outcome assessments including the Modified Rankin Scale (mRS) and the Hospital Anxiety and Depression Scale (HADS). Independent predictors of poor functional (mRS>2) and mood outcomes (HADS≥10) were determined using univariate and multivariate statistics.

Results: Of 247 subjects (74% female, mean age 55), 7% had poor functional outcome. Depression was reported in 17%. Poor functional outcome was significantly associated with a longer hospitalization (mean 26 days, p=0.02), placement of an EVD and VP shunt (p=0.008 & 0.02) and antibiotic use (p=0.001). Depression was significantly associated with poor functional outcome, prior history of depression, and vasospasm (p=0.001, 0.004 & 0.05). Depression showed a trend in those who received an EVD, ventilator, and antibiotics. Depression was not significantly associated with treatment modality. Multivariate logistic analyses demonstrated that poor functional outcome (OR=5.25, CI=1.44-19.10, p=0.01), history of depression (OR=7.66, CI=1.87-31.45, p=0.005), and vasospasm (OR=2.65, CI=1.04-6.75, p=0.04) remain significant predictors of depression, however, EVD, ventilator, antibiotics, and Hunt Hess Grade are not significant.

Conclusion: Depression is not uncommon after SAH, and highly associated with poor neurological recovery at 6 months. Risk factors for development of depression include prior history of depression and cerebral vasospasm. Based on these results, we recommend screening for depression and consideration for early treatment for patients at highest risk after SAH.

Prognosis of untreated strokes due to anterior circulation proximal intracranial arterial occlusions detected by use of computed tomography angiography

IMPORTANCE

Limited data exist regarding the natural history of proximal intracranial arterial occlusions. OBJECTIVE To investigate the outcomes of patients who had an acute ischemic stroke attributed to an anterior circulation proximal intracranial arterial occlusion.

DESIGN, SETTING, AND PARTICIPANTS

A prospective cohort study at 2 university-based hospitals from 2003 to 2005 in which nonenhanced computed tomography scans and computed tomography angiograms were obtained at admission of all adult patients suspected of having an ischemic stroke in the first 24 hours of symptom onset.

EXPOSURE

Anterior circulation proximal intracranial arterial occlusion.

MAIN OUTCOMES AND MEASURES

Frequency of good outcome (defined as a modified Rankin Scale score of ≤ 2) and mortality at 6 months.

RESULTS

A total of 126 patients with a unilateral complete occlusion of the intracranial internal carotid artery (ICA; 26 patients: median National Institutes of Health Stroke Scale [NIHSS] score, 11 [interquartile range, 5-17]), of the M1 segment of the middle cerebral artery (MCA; 52 patients: median NIHSS score, 13 [interquartile range, 6-16]), or of the M2 segment of the MCA (48 patients: median NIHSS score, 7 [interquartile range, 4-15]) were included. Of these 3 groups of patients, 10 (38.5%), 20 (38.5%), and 26 (54.2%) with ICA, MCA-M1, and MCA-M2 occlusions, respectively, achieved a modified Rankin Scale score of 2 or less, and 6 (23.1%), 12 (23.1%), and 10 (20.8%) were dead at 6 months. Worse outcomes were seen in patients with a baseline NIHSS score of 10 or higher, with a modified Rankin Scale score of 2 or less achieved in only 7.1% (1 of 14), 23.5% (8 of 34), and 22.7% (5 of 22) of patients and mortality rates of 35.7% (5 of 14), 32.4% (11 of 34), and 40.9% (9 of 22) among patients with ICA, MCA-M1, and MCA-M2 occlusions, respectively. Age (odds ratio, 0.94 [95% CI, 0.91-0.98]), NIHSS score (odds ratio, 0.73 [95% CI, 0.64-0.83]), and strength of leptomeningeal collaterals (odds ratio, 2.37 [95% CI, 1.08-5.20]) were independently associated with outcome, whereas the level of proximal intracranial arterial occlusion (ICA vs MCA-M1 vs MCA-M2) was not.

CONCLUSIONS AND RELEVANCE

The natural history of proximal intracranial arterial occlusion is variable, with poor outcomes overall. Stroke severity and collateral flow appear to be more important than the level of proximal intracranial arterial occlusion in determining outcomes. Our results provide useful data for proper patient selection and sample size calculations in the design of new clinical trials aimed at recanalization therapies.

THRIVE Score Predicts Ischemic Stroke Outcomes and Thrombolytic Hemorrhage Risk in VISTA

Background and Purpose—

In previous studies, the Totaled Health Risks in Vascular Events (THRIVE) score has shown broad utility, allowing prediction of clinical outcome, death, and risk of hemorrhage after tissue-type plasminogen activator (tPA) treatment, irrespective of the type of acute stroke therapy applied to the patient.

Methods—

We used data from the Virtual International Stroke Trials Archive to further validate the THRIVE score in a large cohort of patients receiving tPA or no acute treatment, to confirm the relationship between THRIVE and hemorrhage after tPA, and to compare the THRIVE score with several other available outcome prediction scores.

Results—

The THRIVE score strongly predicts clinical outcome (odds ratio, 0.55 for good outcome [95% CI, 0.53–0.57]; P <0.001), mortality (odds ratio, 1.57 [95% confidence interval, 1.50–1.64]; P <0.001), and risk of intracerebral hemorrhage after tPA (odds ratio, 1.34 [95% confidence interval, 1.22–1.46]; P <0.001). The relationship between THRIVE score and outcome is not influenced by the independent relationship of tPA administration and outcome. In receiver operator characteristic curve analysis, the THRIVE score was superior to several other available outcome prediction scores in the prediction of clinical outcome and mortality.

Conclusions—

The THRIVE score is a simple-to-use tool to predict clinical outcome, mortality, and risk of hemorrhage after thrombolysis in patients with ischemic stroke. Despite its simplicity, the THRIVE score performs better than several other outcome prediction tools. A free Web calculator for the THRIVE score is available at http://www.thrivescore.org .

Stroke treatment academic industry roundtable: research priorities in the assessment of neurothrombectomy devices

BACKGROUND AND PURPOSE

The goal of the Stroke Treatment Academic Industry Roundtable (STAIR) meetings is to advance the development of stroke therapies. At STAIR VIII, consensus recommendations were developed for clinical trial strategies to demonstrate the benefit of endovascular reperfusion therapies for acute ischemic stroke.

SUMMARY OF REVIEW

Prospects for success with forthcoming endovascular trials are robust, because new neurothrombectomy devices have superior reperfusion efficacy compared with earlier-generation interventions. Specific recommendations are provided for trial designs in 3 populations: (1) patients undergoing intravenous fibrinolysis, (2) early patients ineligible for or having failed intravenous fibrinolysis, and (3) wake-up and other late-presenting patients. Among intravenous fibrinolysis-eligible patients, key principles are that CT or MRI confirmation of target arterial occlusions should precede randomization; endovascular intervention should be pursued with the greatest rapidity possible; and combined intravenous and neurothrombectomy therapy is more promising than neurothrombectomy alone. Among patients ineligible for or having failed intravenous fibrinolysis, scientific equipoise was affirmed and the need to randomize all eligible patients emphasized. Vessel imaging to confirm occlusion is mandatory, and infarct core and penumbral imaging is desirable in later time windows. Additional STAIR VIII recommendations include approaches to test multiple devices in a single trial, utility weighting of disability end points, and adaptive designs to delineate time and tissue injury thresholds at which benefits from intervention no longer accrue.

CONCLUSIONS

Endovascular research priorities in acute ischemic stroke are to perform trials testing new, highly effective neuro thrombectomy devices rapidly deployed in patients confirmed to have target vessel occlusions.

THRIVE score predicts outcomes with a third-generation endovascular stroke treatment device in the TREVO-2 trial

BACKGROUND AND PURPOSE

Several outcome prediction scores have been tested in patients receiving acute stroke treatment with previous generations of endovascular stroke treatment devices. The TREVO-2 trial was a randomized controlled trial comparing a novel endovascular stroke treatment device (the Trevo device) to a previous-generation endovascular stroke treatment device (the Merci device).

METHODS

We used data from the TREVO-2 trial to validate the Totaled Health Risks in Vascular Events (THRIVE) score in patients receiving treatment with a third-generation endovascular stroke treatment device and to compare THRIVE to other predictive scores. We used logistic regression to model outcomes and compared score performance with receiver operating characteristic curve analysis.

RESULTS

In the TREVO-2 trial, the THRIVE score strongly predicts clinical outcome and mortality. The relationship between THRIVE score and outcome is not influenced by either success of recanalization or the type of device used (Trevo versus Merci). The superiority of the Trevo device to the Merci device is evident particularly among patients with a low-to-moderate THRIVE score (0-5; 53.8% good outcome with Trevo versus 27.5% good outcome with Merci). In receiver operating characteristic curve analysis, the THRIVE score was comparable or superior to several other outcome prediction scores (HIAT, HIAT-2, SPAN-100, and iScore).

CONCLUSIONS

The THRIVE score strongly predicts clinical outcome and mortality in the TREVO-2 trial. Taken together with THRIVE validation data from patients receiving intravenous tissue-type plasminogen activator or no acute treatment, the THRIVE score has broad predictive power in patients with acute ischemic stroke, which is likely because THRIVE reflects a set of strong nonmodifiable predictors of stroke outcome. A free Web calculator for the THRIVE score is available at http://www.thrivescore.org.