Modeling diffusion-weighted imaging lesion expansion between 2 and 24 h after endovascular thrombectomy in acute ischemic stroke

PURPOSE

Diffusion-weighted imaging (DWI) lesion expansion after endovascular thrombectomy (EVT) is not well characterized. We used serial diffusion-weighted magnetic resonance imaging (MRI) to measure lesion expansion between 2 and 24 h after EVT.

METHODS

In this single-center observational analysis of patients with acute ischemic stroke due to large vessel occlusion, DWI was performed post-EVT (< 2 h after closure) and 24-h later. DWI lesion expansion was evaluated using multivariate generalized linear mixed modeling with various clinical moderators.

RESULTS

We included 151 patients, of which 133 (88%) had DWI lesion expansion, defined as a positive change in lesion volume between 2 and 24 h. In an unadjusted analysis, median baseline DWI lesion volume immediately post-EVT was 15.0 mL (IQR: 6.6-36.8) and median DWI lesion volume 24 h post-EVT was 20.8 mL (IQR: 9.4-66.6), representing a median change of 6.1 mL (IQR: 1.5-17.7), or a 39% increase. There were no significant associations among univariable models of lesion expansion. Adjusted models of DWI lesion expansion demonstrated that relative lesion expansion (defined as final/initial DWI lesion volume) was consistent across eTICI scores (0-2a, 0.52%; 2b, 0.49%; 2c-3, 0.42%, p = 0.69). For every 1 mL increase in lesion volume, there was 2% odds of an increase in 90-day mRS (OR: 1.021, 95%CI [1.009, 1.034], p < 0.001).

CONCLUSION

We observed substantial lesion expansion post-EVT whereby relative lesion expansion was consistent across eTICI categories, and greater absolute lesion expansion was associated with worse clinical outcome. Our findings suggest that alternate endpoints for cerebroprotectant trials may be feasible.

Risk of recurrent stroke in patients with atrial fibrillation treated with oral anticoagulants alone or in combination with anti-platelet therapy

INTRODUCTION

Ischaemic stroke patients with atrial fibrillation (AF) are at high risk of stroke recurrence despite oral anticoagulation therapy. Patients with cardiovascular comorbidities may take both antiplatelet and oral anticoagulation therapy (OAC/AP). Our study aims to evaluate the safety and efficacy of OAC/AP therapy as secondary prevention in people with AF and ischaemic stroke.

PATIENTS AND METHODS

We performed a post-hoc analysis of pooled individual data from multicenter prospective cohort studies and compared outcomes in the OAC/AP cohort and patients on DOAC/VKA anticoagulation alone (OAC cohort). Primary outcome was a composite of ischaemic stroke, systemic embolism, intracranial bleeding, and major extracranial bleeding, while secondary outcomes were ischaemic and haemorrhagic events considered separately. A multivariable logistic regression analysis was performed to identify independent predictors for outcome events. To compare the risk of outcome events between the two cohorts, the relation between the survival function and the set of explanatory variables were calculated by Cox proportional hazard models and the results were reported as adjusted hazard ratios (HR). Finally another analysis was performed to compare the overall risk of outcome events in both OAC/AP and OAC cohorts after propensity score matching (PSM).

RESULTS

During a mean follow-up time of 7.5 ± 9.1 months (median follow-up time 3.5 months, interquartile range ±3), 2284 stroke patients were on oral anticoagulants and 215 were on combined therapy. The multivariable model demonstrated that the composite outcome is associated with age (OR: 1.03, 95% CI: 1.01-1.04 for each year increase) and concomitant antiplatelet therapy (OR: 2.2, 95% CI: 1.48-3.27), the ischaemic outcome with congestive heart failure (OR: 1.55, 95% CI: 1.02-2.36) and concomitant antiplatelet therapy (OR: 1.93, 95% CI: 1.19-3.13) and the haemorrhagic outcome with age (OR: 1.03, 95% CI: 1.01-1.06 for each year increase), alcoholism (OR: 2.15, 95% CI: 1.06-4.39) and concomitant antiplatelet therapy (OR: 2.22, 95% CI: 1.23-4.02). Cox regression demonstrated a higher rate of the composite outcome (hazard ratio of 1.93 [95% CI, 1.35-2.76]), ischaemic events (HR: 2.05 [95% CI: 1.45-2.87]) and bleeding outcomes (HR: 1.90 [95% CI, 1.06-3.40]) in OAC/AP cohort. After PSM analysis, the composite outcome remained more frequent in people treated with OAC + AP (RR: 1.70 [95% CI, 1.05-2.74]).

DISCUSSION

Secondary prevention with combination of oral anticoagulant and antiplatelet therapy after ischaemic stroke was associated with worse outcomes in our cohort.

CONCLUSION

Further research is needed to improve secondary prevention by investigating the mechanisms of recurrent ischaemic stroke in patients with atrial fibrillation.

Minimizing blood loss with direct percutaneous polymethylmethacrylate embolization before corpectomy for vascular spinal tumors

Background

Standard surgical treatment for vascular spinal tumors, including renal cell carcinomas and hemangiomas, may result in significant blood loss despite preoperative arterial tumor embolization.

Methods

This is a retrospective review of 12 patients who underwent direct percutaneous polymethylmethacrylate embolization (DPPE) with or without feeding artery embolization before partial or complete corpectomy for the resection of vascular spinal tumors (2013-2018). Estimated blood loss (EBL) was compared to the blood loss reported in the literature and to patients receiving standard arterial embolization before surgery.

Results

The mean EBL for 12 patients was 1030 mL; three of 12 patients required blood transfusions. For the single level corpectomies, the EBL ranged from 100 mL to 3900 mL (mean 640 mL). This mean blood loss was not increased in patients receiving only DPPE preoperatively versus those patients receiving preoperative arterial embolization in addition to DPPE (1005 vs. 1416 mL); in fact, the EBL was significantly reduced for those undergoing DPPE alone.

Conclusion

In this initial study, nine patients treated with DPPE embolization alone before spinal tumor resection demonstrated reduction of intraoperative blood loss compared to three patients having arterial embolization with DDPE.

Recurrence risk in symptomatic intracranial stenosis treated medically in the real world

BACKGROUND

The risk of early recurrence in medically treated patients with intracranial atherosclerotic stenosis (ICAS) may differ in clinical trials versus real-world settings. Delayed enrollment may contribute to lower event rates in ICAS trials. We aim to determine the 30-day recurrence risk in a real-world setting of symptomatic ICAS.

METHODS

We used a comprehensive stroke center stroke registry to identify hospitalized patients with acute ischemic stroke or TIA due to symptomatic 50-99% ICAS. The outcome was recurrent stroke within 30 days. We used adjusted Cox regression models to identify factors associated with increased recurrence risk. We also performed a comparison of 30-day recurrent stroke rates in real world cohorts and clinical trials.

RESULTS

Among 131 hospitalizations with symptomatic 50-99% ICAS over 3 years, 80 hospitalizations of 74 patients (mean age 71.6 years, 55.41% men) met the inclusion criteria. Over 30 days, 20.6 % had recurrent stroke; 61.5% (8/13) occurred within first 7 days. The risk was higher in patients not receiving dual antiplatelet therapy (HR 3.92 95% CI 1.30-11.84, p = 0.015) and hypoperfusion mismatch volume >3.5 mL at a T max>6 s threshold (HR 6.55 95% CI 1.60-26.88, p < 0.001). The recurrence risk was similar to another real world ICAD cohort (20.2%), and higher than that seen in clinical trials (2.2%-5.7%), even in those treated with maximal medical treatment or meeting inclusion criteria for trials.

CONCLUSIONS

In patients with symptomatic ICAS, the real-world recurrence of ischemic events is higher than that seen in clinical trials, even in subgroups receiving the same pharmacological treatment strategies.

Abstract WMP77: High Early Recurrence In Symptomatic Intracranial Atherosclerosis Treated Medically In The Real World Compared To Clinical Trials

Background: While optimizing medical treatment contributed to the low recurrence risk seen in SAMMPRIS medical arm, other factors such as delayed enrollment may have contributed to this low event rate. In this study, we aim to determine the 30-day recurrence risk in a real-world setting in patients with symptomatic intracranial atherosclerosis.

Methods: We used a stroke registry of a comprehensive stroke center to identify hospitalized patients with acute ischemic stroke in the setting of symptomatic intracranial atherosclerosis of the ICA, M1, vertebral, or basilar with 50-99% luminal narrowing. We excluded patients with a clear indication for anticoagulation and those who received endovascular treatment. The outcome was recurrent stroke attributed to the affected artery within 30-days. We used adjusted Cox regression models to identify factors associated with increased recurrence risk.

Results: Among 131 symptomatic 50-99% intracranial stenosis hospitalizations over 3 years, 66 patients met the inclusion criteria. The mean age was 71.9 years and 51.5% were men; 75.8% were treated with best medical management (dual antiplatelet therapy/high intensity stain therapy). Over 30-day follow-up, 21.2 % had recurrent stroke, 57.1% (8/14) occurred within first 7 days. The recurrence risk was similar to another real world ICAD cohort, and higher than that seen in SAMMPRIS (Figure). While maximal medical treatment was the only factor associated with a lower rate of recurrence (OR 0.32 95% CI 0.09-1.12, p = 0.075), the recurrence rate in patients treated with maximal medical therapy (16.0%, 95% CI 8.1-29.3%) and those SAMMPRIS eligible (17.6%, 95% CI 7.9-34.9%) remained elevated.

Conclusions: In patients with symptomatic ICAS, the real-world recurrence is higher than that seen in clinical trials, despite optimally using the same medical treatment strategies. This may suggest that the low risk of recurrence achieved in clinical trials may not apply to real world practice.

Abstract TP75: Waking Up To A New Wake-Up Stroke Protocol Is Feasible And Safe

Introduction: Up to 25% of strokes are recognized upon awakening. Recent studies have demonstrated that a “tissue clock” rather than a time clock can be used to identify patients who may benefit from intravenous thrombolytics (IVT) beyond 4.5 hours from last known well (LKW). Consistent access to hyperacute MRI limits many centers from treating wake-up stroke patients. We created a formal protocol of clinical and imaging criteria to standardize evaluation and management of wake-up strokes.

Methods: This retrospective, observational study reviewed consecutive patients admitted to our Comprehensive Stroke Center who qualified for the wake-up protocol between February 2022 and June 2022. The implemented protocol, based on clinical trials’ inclusion criteria, is comprised of the following: 1) arrival within 12 hours from LKW and within 4.5 hours from symptom discovery; 2) high suspicion for acute ischemic stroke; 3) no contraindication to MRI; 4) NIHSS of at least 4; 5) baseline mRS 0-3; 6) no absolute contraindications to IVT. For patients meeting above inclusion criteria, emergent MRI with perfusion was performed. Diffusion-FLAIR mismatch (signal intensity ratio) and diffusion-perfusion mismatch were reviewed to determine thrombolysis eligibility by a trained neuroradiologist or vascular neurologist.

Results: Ten patients qualified for the wake-up protocol in the first five months of protocol implementation. Median NIHSS was 7, median LKW to arrival time was 8 hours, and median door to MRI time was 72.5 minutes. A final diagnosis of ischemic stroke was made in 80% of these cases. Overall, 50% were eligible for IVT based on our criteria, and 30% received thrombolysis. Median door to needle time was 92 minutes (range 75-117). There were no symptomatic intracranial hemorrhages. All patients treated with IVT were discharged home with no to minimal residual deficits with mRS 0-1 and median NIHSS at discharge of 2 (range 0-4).

Conclusion: A formal protocol for wake-up stroke management allowed a streamlined approach to expand the number of IVT-eligible cases. Continued efforts are needed to improve door to needle times in such cases and to follow clinical courses of treated patients.

Abstract WP79: Addition Of Multidisciplinary Novel Processes Reduces The Door-to-Needle Time In Acute Ischemic Stroke

Introduction: It is well established that reduced door-to-needle (DTN) time leads to improved outcomes in acute ischemic stroke. Rhode Island Hospital is a Comprehensive Stroke Center focused on improving outcomes by seeking novel methods to improve the DTN to below the institutional goal of a median of < 30 minutes.

Methods: We sought to reduce DTN time by the following methods: 1) Addition of an electronic DTN Timer appearing in the Electronic Medical Record (EMR) to improve situational awareness of elapsed time in Code Strokes in real time (Figure). 2) Creation of a multidisciplinary Thrombolysis Focus Group to analyze data and improve processes. 3) Increased awareness of metric exclusion criteria and ease of processes for providers to document exclusions. 4) Concurrent review of each thrombolysis case with direct provider feedback and opportunity to appropriately document and clarify delays. 5) Creation of a thrombolysis Time-Out process.

Results: The median DTN for the pre-implementation period of January 2020 to August 2021 was 40.3 minutes compared to 35.8 min for the post-implantation period of September 2021 to June 2022. Additionally, the percent of thrombolysis cases meeting the institutional goal of under 30 minutes improved from 22.6% to 29.8% percent (Figure) and when exclusions were applied, this percentage improved from 29.8% to 49.4% (Figure).

Conclusion: Novel measures to reduce the DTN time in acute stroke thrombolysis can positively impact both the door-to-needle time and percent of cases under the institutional DTN time goal.

Figure 1.

Abstract 138: Hypoperfusion Delay Volume Predicts Early Stroke Recurrence Risk In Symptomatic Anterior Circulation Intracranial Atherosclerotic Disease

Introduction: Data on predictors of early stroke recurrence in patients with symptomatic intracranial atherosclerotic disease (sICAD) is limited. We hypothesized that hypoperfusion delay predicts stroke recurrence within 90-days.

Methods: We retrospectively collected all patients hospitalized with anterior circulation sICAD over 3 years (April 2019-April 2022) at a comprehensive stroke center. We collected demographics, clinical risk factors, radiological variables, and treatment strategies. Patients with an indication for anticoagulation such as atrial fibrillation and those with intracranial stenting or angioplasty were excluded. The outcome (verified by two independent reviewers) was recurrent stroke within 90 days in the affected artery. We assessed factors associated with stroke recurrence. We measured the effect of hypoperfusion delay volume on stroke recurrence using Cox-regression models.

Results: Out of 131 sICAD hospitalizations during the study period, 66 involved the middle cerebral artery (MCA) M1 segment or intracranial internal carotid artery (ICA) and 44 patients met the inclusion criteria. The mean age was 71 years and 41% were women; 75% were treated with best medical management (dual antiplatelet therapy/high intensity statin therapy); and 75% had baseline perfusion imaging performed. Over 90 days, 11/44 (25%) patients had recurrent stroke. Factors associated with recurrence stroke were no best medical management (15.2% vs. 54.5%, p = 0.02), hypoperfusion Tmax>4 sec mismatch volume (p = 0.003), and hypoperfusion delay Tmax>6 sec mismatch volume (p=0.01). Using Youden’s cutoff for Tmax>4 sec mismatch (13 mL) and for Tmax>6 sec mismatch (5 mL), the risk of recurrent stroke at 90 days in separate models was higher in patients with Tmax>4 sec delay mismatch volume > 13 mL (HR 11.98 95% CI 1.48-96.96 p=0.02) and Tmax>6 sec mismatch volume > 5 mL (HR 4.37 95% CI 1.02-18.82, p=0.048). Effect size of the associations did not meaningfully change after adjusting for best medical management.

Conclusion: Hypoperfusion delay is associated with an increased recurrent stroke risk within 90 days in patients with sICAD, despite best medical management. Validation by large prospective studies is warranted.

Recurrent Ischemic Stroke and Bleeding in Patients With Atrial Fibrillation Who Suffered an Acute Stroke While on Treatment With Nonvitamin K Antagonist Oral Anticoagulants: The RENO-EXTEND Study

BACKGROUND

In patients with atrial fibrillation who suffered an ischemic stroke while on treatment with nonvitamin K antagonist oral anticoagulants, rates and determinants of recurrent ischemic events and major bleedings remain uncertain.

METHODS

This prospective multicenter observational study aimed to estimate the rates of ischemic and bleeding events and their determinants in the follow-up of consecutive patients with atrial fibrillation who suffered an acute cerebrovascular ischemic event while on nonvitamin K antagonist oral anticoagulant treatment. Afterwards, we compared the estimated risks of ischemic and bleeding events between the patients in whom anticoagulant therapy was changed to those who continued the original treatment.

RESULTS

After a mean follow-up time of 15.0±10.9 months, 192 out of 1240 patients (15.5%) had 207 ischemic or bleeding events corresponding to an annual rate of 13.4%. Among the events, 111 were ischemic strokes, 15 systemic embolisms, 24 intracranial bleedings, and 57 major extracranial bleedings. Predictive factors of recurrent ischemic events (strokes and systemic embolisms) included CHA₂DS₂-VASc score after the index event (odds ratio [OR], 1.2 [95% CI, 1.0-1.3] for each point increase; P=0.05) and hypertension (OR, 2.3 [95% CI, 1.0-5.1]; P=0.04). Predictive factors of bleeding events (intracranial and major extracranial bleedings) included age (OR, 1.1 [95% CI, 1.0-1.2] for each year increase; P=0.002), history of major bleeding (OR, 6.9 [95% CI, 3.4-14.2]; P=0.0001) and the concomitant administration of an antiplatelet agent (OR, 2.8 [95% CI, 1.4-5.5]; P=0.003). Rates of ischemic and bleeding events were no different in patients who changed or not changed the original nonvitamin K antagonist oral anticoagulants treatment (OR, 1.2 [95% CI, 0.8-1.7]).

CONCLUSIONS

Patients suffering a stroke despite being on nonvitamin K antagonist oral anticoagulant therapy are at high risk of recurrent ischemic stroke and bleeding. In these patients, further research is needed to improve secondary prevention by investigating the mechanisms of recurrent ischemic stroke and bleeding.

Ipsilateral internal carotid artery web and acute ischemic stroke: A cohort study, systematic review and meta-analysis

Introduction

The carotid web is a compelling potential mechanism of embolic ischemic stroke. In this study, we aim to determine the prevalence of ipsilateral carotid web in a cohort of ischemic stroke patients and to perform a systematic review and meta-analysis of similar cohorts.

Patients & methods

We performed a retrospective, observational, cohort study of acute ischemic stroke patients admitted to a comprehensive stroke center from June 2012 to September 2017. Carotid web was defined on computed tomography angiography (CTA) as a thin shelf of non-calcified tissue immediately distal to the carotid bifurcation. We described the prevalence of carotid artery webs in our cohort, then performed a systematic review and meta-analysis of similar cohorts in the published literature.

Results

We identified 1,435 potentially eligible patients of whom 879 met criteria for inclusion in our analysis. An ipsilateral carotid web was detected in 4 out of 879 (0.45%) patients, of which 4/4 (1.6%) were in 244 patients with cryptogenic stroke and 3/4 were in 66 (4.5%) patients <60 years old with cryptogenic stroke. Our systematic review yielded 3,192 patients. On meta-analysis, the pooled prevalence of ipsilateral carotid web in cryptogenic stroke patients <60 was 13% (95% CI: 7%-22%; I² = 66.1%). The relative risk (RR) of ipsilateral versus contralateral carotid web in all patients was 2.5 (95% CI 1.5–4.2, p = 0.0009) whereas in patients less than 60 with cryptogenic stroke it was 3.0 (95% CI 1.6–5.8, p = 0.0011).

Discussion

Carotid webs are more common in young patients with cryptogenic stroke than in other stroke subtypes. Future studies concerning the diagnosis and secondary prevention of stroke associated with carotid web should focus on this population.

Strength of Association between Infarct Volume and Clinical Outcome Depends on the Magnitude of Infarct Size: Results from the ESCAPE-NA1 Trial

BACKGROUND AND PURPOSE

Infarct volume is an important predictor of clinical outcome in acute stroke. We hypothesized that the association of infarct volume and clinical outcome changes with the magnitude of infarct size.

MATERIALS AND METHODS

Data were derived from the Safety and Efficacy of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke (ESCAPE-NA1) trial, in which patients with acute stroke with large-vessel occlusion were randomized to endovascular treatment plus either nerinetide or a placebo. Infarct volume was manually segmented on 24-hour noncontrast CT or DWI. The relationship between infarct volume and good outcome, defined as mRS 0-2 at 90 days, was plotted. Patients were categorized on the basis of visual grouping at the curve shoulders of the infarct volume/outcome plot. The relationship between infarct volume and adjusted probability of good outcome was fitted with linear or polynomial functions as appropriate in each group.

RESULTS

We included 1099 individuals in the study. Median infarct volume at 24 hours was 24.9 mL (interquartile range [IQR] = 6.6-92.2 mL). On the basis of the infarct volume/outcome plot, 4 infarct volume groups were defined (IQR = 0-15 mL, 15.1-70 mL, 70.1-200 mL, >200 mL). Proportions of good outcome in the 4 groups were 359/431 (83.3%), 219/337 (65.0%), 71/201 (35.3%), and 16/130 (12.3%), respectively. In small infarcts (IQR = 0-15 mL), no relationship with outcome was appreciated. In patients with intermediate infarct volume (IQR = 15-200 mL), there was progressive importance of volume as an outcome predictor. In infarcts of > 200 mL, outcomes were overall poor.

CONCLUSIONS

The relationship between infarct volume and clinical outcome varies nonlinearly with the magnitude of infarct size. Infarct volume was linearly associated with decreased chances of achieving good outcome in patients with moderate-to-large infarcts, but not in those with small infarcts. In very large infarcts, a near-deterministic association with poor outcome was seen.

Penumbra Consumption Rates Based on Time-to-Maximum Delay and Reperfusion Status: A Post Hoc Analysis of the DEFUSE 3 Trial

BACKGROUND AND PURPOSE

In patients with acute large vessel occlusion, the natural history of penumbral tissue based on perfusion time-to-maximum (T_max) delay is not well established in relation to late-window endovascular thrombectomy. In this study, we sought to evaluate penumbra consumption rates for T_max delays in patients with large vessel occlusion evaluated between 6 and 16 hours from last known normal.

METHODS

This is a post hoc analysis of the DEFUSE 3 trial (The Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke), which included patients with an acute ischemic stroke due to anterior circulation occlusion within 6 to 16 hours of last known normal. The primary outcome is percentage penumbra consumption, defined as (24-hour magnetic resonance imaging infarct volume-baseline core infarct volume)/(T_max 6 or 10 s volume-baseline core volume). We stratified the cohort into 4 categories based on treatment modality and Thrombolysis in Cerebral Infarction (TICI score; untreated, TICI 0-2a, TICI 2b, and TICI3) and calculated penumbral consumption rates in each category.

RESULTS

We included 141 patients, among whom 68 were untreated. In the untreated versus TICI 3 patients, a median (interquartile range) of 53.7% (21.2%-87.7%) versus 5.3% (1.1%-14.6%) of penumbral tissue was consumed based on T_max >6 s (P<0.001). In the same comparison for T_max>10 s, we saw a difference of 165.4% (interquartile range, 56.1%-479.8%) versus 25.7% (interquartile range, 3.2%-72.1%; P<0.001). Significant differences were not demonstrated between untreated and TICI 0-2a patients for penumbral consumption based on T_max >6 s (P=0.52) or T_max >10 s (P=0.92).

CONCLUSIONS

Among extended window endovascular thrombectomy patients, T_max >10-s mismatch volume may comprise large volumes of salvageable tissue, whereas nearly half the T_max >6-s mismatch volume may remain viable in untreated patients at 24 hours.

Radiologic Patterns of Intracranial Hemorrhage and Clinical Outcome after Endovascular Treatment in Acute Ischemic Stroke: Results from the ESCAPE-NA1 Trial

Background Intracranial hemorrhage is a known complication after endovascular treatment in patients with acute ischemic stroke due to large vessel occlusion, but the association between radiologic hemorrhage severity and outcome is controversial. Purpose To investigate the prevalence and impact on outcome of intracranial hemorrhage and hemorrhage severity after endovascular stroke treatment. Materials and Methods The Efficacy and Safety of Nerinetide for the Treatment of Acute Ischemic Stroke (ESCAPE-NA1) trial enrolled participants with acute large vessel occlusion stroke who underwent endovascular treatment from March 1, 2017, to August 12, 2019. Evidence of any intracranial hemorrhage, hemorrhage multiplicity, and radiologic severity, according to the Heidelberg classification (hemorrhagic infarction type 1 [HI1], hemorrhagic infarction type 2 [HI2], parenchymal hematoma type 1 [PH1], and parenchymal hematoma type 2 [PH2]) was assessed at CT or MRI 24 hours after endovascular treatment. Good functional outcome, defined as a modified Rankin score of 0-2 at 90 days, was compared between participants with intracranial hemorrhage and those without intracranial hemorrhage at follow-up imaging and between hemorrhage subtypes. Poisson regression was performed to obtain adjusted effect size estimates for the presence of any intracranial hemorrhage and hemorrhage subtypes at good functional outcome. Results Of 1097 evaluated participants (mean age, 69 years ± 14 [standard deviation]; 551 men), any degree of intracranial hemorrhage was observed in 372 (34%). Good outcomes were less often achieved among participants with hemorrhage than among those without hemorrhage at follow-up imaging (164 of 372 participants [44%] vs 500 of 720 [69%], respectively; P < .01). After adjusting for baseline variables and infarct volume, intracranial hemorrhage was not associated with decreased chances of good outcome (adjusted risk ratio [RR] = 0.91 [95% CI: 0.82, 1.02], P = .10), but there was a graded relationship of radiologic hemorrhage severity and outcomes, whereby PH1 (RR = 0.77 [95% CI: 0.61, 0.97], P = .03) and PH2 (RR = 0.41 [95% CI: 0.21, 0.81], P = .01) were associated with decreased chances of good outcome. Conclusion Any degree of intracranial hemorrhage after endovascular treatment was seen in one-third of participants. A graded association existed between radiologic hemorrhage severity and outcome. Hemorrhagic infarction was not associated with outcome, whereas parenchymal hematoma was strongly associated with poor outcome, independent of infarct volume. © RSNA, 2021 Clinical trial registration no. NCT01778335 Online supplemental material is available for this article.

The Effect of Hyperglycemia on Infarct Growth after Reperfusion: An Analysis of the DEFUSE 3 trial

BACKGROUND AND PURPOSE

Brain infarct growth, despite successful reperfusion, decreases the likelihood of good functional outcome after ischemic stroke. In patients undergoing reperfusion, admission glucose is associated with poor outcome but the effect of glucose level on infarct growth is not well studied.

MATERIALS AND METHODS

This is a secondary analysis of the DEFUSE 3 trial. The primary predictor was baseline glucose level and the primary outcome is the change of the ischemic core volume from the baseline to 24-hour follow-up imaging (∆core), transformed as a cube root to reduce right skew. We included DEFUSE 3 patients who were randomized to endovascular therapy, had perfusion imaging data at baseline, an MRI at 24 hours, and who achieved TICI 2b or 3. Linear regression models, both unadjusted and adjusted, were fit to the primary outcome and all models included the baseline core volume as a covariate to normalize ∆core.

RESULTS

We identified 62 patients who met our inclusion criteria. The mean age was 68.1±13.1 (years), 48.4% (30/62) were men, and the median (IQR) cube root of ∆core was 2.8 (2.0-3.8) mL. There was an association between baseline glucose level and normalized ∆core in unadjusted analysis (beta coefficient 0.010, p = 0.01) and after adjusting for potential confounders (beta coefficient 0.008, p = 0.03).

CONCLUSION

In acute ischemic stroke patients with large vessel occlusion undergoing successful endovascular reperfusion, baseline hyperglycemia is associated with infarction growth. Further study is needed to establish potential neuroprotective benefits of aggressive glycemic control prior to and after reperfusion.

Considerations for Antiplatelet Management of Carotid Stenting in the Setting of Mechanical Thrombectomy: A Delphi Consensus Statement

BACKGROUND AND PURPOSE

There are only few data and lack of consensus regarding antiplatelet management for carotid stent placement in the setting of endovascular stroke treatment. We aimed to develop a consensus-based algorithm for antiplatelet management in acute ischemic stroke patients undergoing endovascular treatment and simultaneous emergent carotid stent placement.

MATERIALS AND METHODS

We performed a literature search and a modified Delphi approach used Web-based questionnaires that were sent in several iterations to an international multidisciplinary panel of 19 neurointerventionalists from 7 countries. The first round included open-ended questions and formed the basis for subsequent rounds, in which closed-ended questions were used. Participants continuously received feedback on the results from previous rounds. Consensus was defined as agreement of ≥70% for binary questions and agreement of ≥50% for questions with >2 answer options. The results of the Delphi process were then summarized in a draft manuscript that was circulated among the panel members for feedback.

RESULTS

A total of 5 Delphi rounds were performed. Panel members preferred a single intravenous aspirin bolus or, in jurisdictions in which intravenous aspirin is not available, a glycoprotein IIb/IIIa receptor inhibitor as intraprocedural antiplatelet regimen and a combination therapy of oral aspirin and a P2Y12 inhibitor in the postprocedural period. There was no consensus on the role of platelet function testing in the postprocedural period.

CONCLUSIONS

More and better data on antiplatelet management for carotid stent placement in the setting of endovascular treatment are urgently needed. Panel members preferred intravenous aspirin or, alternatively, a glycoprotein IIb/IIIa receptor inhibitor as an intraprocedural antiplatelet agent, followed by a dual oral regimen of aspirin and a P2Y12 inhibitor in the postprocedural period.

Challenging the Ischemic Core Concept in Acute Ischemic Stroke Imaging

Endovascular treatment is a highly effective therapy for acute ischemic stroke due to large vessel occlusion and has recently revolutionized stroke care. Oftentimes, ischemic core extent on baseline imaging is used to determine endovascular treatment-eligibility. There are, however, 3 fundamental issues with the core concept: First, computed tomography and magnetic resonance imaging, which are mostly used in the acute stroke setting, are not able to precisely determine whether and to what extent brain tissue is infarcted (core) or still viable, due to variability in tissue vulnerability, the phenomenon of selective neuronal loss and lack of a reliable gold standard. Second, treatment decision-making in acute stroke is multifactorial, and as such, the relative importance of single variables, including imaging factors, is reduced. Third, there are often discrepancies between core volume and clinical outcome. This review will address the uncertainty in terminology and proposes a direction towards more clarity. This theoretical exercise needs empirical data that clarify the definitions further and prove its value.

Antiplatelet Management for Stent-Assisted Coiling and Flow Diversion of Ruptured Intracranial Aneurysms: A DELPHI Consensus Statement

BACKGROUND AND PURPOSE

There is a paucity of data regarding antiplatelet management strategies in the setting of stent-assisted coiling/flow diversion for ruptured intracranial aneurysms. This study aimed to identify current challenges in antiplatelet management during stent-assisted coiling/flow diversion for ruptured intracranial aneurysms and to outline possible antiplatelet management strategies.

MATERIALS AND METHODS

The modified DELPHI approach with an on-line questionnaire was sent in several iterations to an international, multidisciplinary panel of 15 neurointerventionalists. The first round consisted of open-ended questions, followed by closed-ended questions in the subsequent rounds. Responses were analyzed in an anonymous fashion and summarized in the final manuscript draft. The statement received endorsement from the World Federation of Interventional and Therapeutic Neuroradiology, the Japanese Society for Neuroendovascular Therapy, and the Chinese Neurosurgical Society.

RESULTS

Data were collected from December 9, 2019, to March 13, 2020. Panel members achieved consensus that platelet function testing may not be necessary and that antiplatelet management for stent-assisted coiling and flow diversion of ruptured intracranial aneurysms can follow the same principles. Preprocedural placement of a ventricular drain was thought to be beneficial in cases with a high risk of hydrocephalus. A periprocedural dual, intravenous, antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor was preferred as a standard approach. The panel agreed that intravenous medication can be converted to oral aspirin and an oral P2Y12 inhibitor within 24 hours after the procedure.

CONCLUSIONS

More and better data on antiplatelet management of patients with ruptured intracranial aneurysms undergoing stent-assisted coiling or flow diversion are urgently needed. Panel members in this DELPHI consensus study preferred a periprocedural dual-antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor.

Detecting Large Vessel Occlusion at Multiphase CT Angiography by Using a Deep Convolutional Neural Network

Background Large vessel occlusion (LVO) stroke is one of the most time-sensitive diagnoses in medicine and requires emergent endovascular therapy to reduce morbidity and mortality. Leveraging recent advances in deep learning may facilitate rapid detection and reduce time to treatment. Purpose To develop a convolutional neural network to detect LVOs at multiphase CT angiography. Materials and Methods This multicenter retrospective study evaluated 540 adults with CT angiography examinations for suspected acute ischemic stroke from February 2017 to June 2018. Examinations positive for LVO (n = 270) were confirmed by catheter angiography and LVO-negative examinations (n = 270) were confirmed through review of clinical and radiology reports. Preprocessing of the CT angiography examinations included vasculature segmentation and the creation of maximum intensity projection images to emphasize the contrast agent-enhanced vasculature. Seven experiments were performed by using combinations of the three phases (arterial, phase 1; peak venous, phase 2; and late venous, phase 3) of the CT angiography. Model performance was evaluated on the held-out test set. Metrics included area under the receiver operating characteristic curve (AUC), sensitivity, and specificity. Results The test set included 62 patients (mean age, 69.5 years; 48% women). Single-phase CT angiography achieved an AUC of 0.74 (95% confidence interval [CI]: 0.63, 0.85) with sensitivity of 77% (24 of 31; 95% CI: 59%, 89%) and specificity of 71% (22 of 31; 95% CI: 53%, 84%). Phases 1, 2, and 3 together achieved an AUC of 0.89 (95% CI: 0.81, 0.96), sensitivity of 100% (31 of 31; 95% CI: 99%, 100%), and specificity of 77% (24 of 31; 95% CI: 59%, 89%), a statistically significant improvement relative to single-phase CT angiography (P = .01). Likewise, phases 1 and 3 and phases 2 and 3 also demonstrated improved fit relative to single phase (P = .03). Conclusion This deep learning model was able to detect the presence of large vessel occlusion and its diagnostic performance was enhanced by using delayed phases at multiphase CT angiography examinations. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Ospel and Goyal in this issue.

Thrombectomy in DAWN- and DEFUSE-3-Ineligible Patients: A Subgroup Analysis From the BEST Prospective Cohort Study

BACKGROUND

Because of the overwhelming benefit of thrombectomy for highly selected trial patients with large vessel occlusion (LVO), some trial-ineligible patients are being treated in practice.

OBJECTIVE

To determine the safety and efficacy of thrombectomy in DAWN/DEFUSE-3-ineligible patients.

METHODS

Using a multicenter prospective observational study of consecutive patients with anterior circulation LVO who underwent late thrombectomy, we compared symptomatic intracerebral hemorrhage (sICH) and good outcome (90-d mRS 0-2) among DAWN/DEFUSE-3-ineligible patients to trial-eligible patients and to untreated DAWN/DEFUSE-3 controls.

RESULTS

Ninety-eight patients had perfusion imaging and underwent thrombectomy >6 h; 46 (47%) were trial ineligible (41% M2 occlusions, 39% mild deficits, 28% ASPECTS <6). In multivariable regression, the odds of a good outcome (aOR 0.76, 95% CI 0.49-1.19) and sICH (aOR 3.33, 95% CI 0.42-26.12) were not different among trial-ineligible vs eligible patients. Patients with mild deficits were more likely to achieve a good outcome (aOR 3.62, 95% CI 1.48-8.86) and less sICH (0% vs 10%, P = .16), whereas patients with ASPECTS <6 had poorer outcomes (aOR 0.14, 95% CI 0.05-0.44) and more sICH (aOR 24, 95% CI 5.7-103). Compared to untreated DAWN/DEFUSE-3 controls, trial-ineligible patients had more sICH (13%BEST vs 3%DAWN [P = .02] vs 4%DEFUSE [P = .05]), but were more likely to achieve a good outcome at 90 d (36%BEST vs 13%DAWN [P < .01] vs 17%DEFUSE [P = .01]).

CONCLUSION

Thrombectomy is used in practice for some patients ineligible for the DAWN/DEFUSE-3 trials with potentially favorable outcomes. Additional trials are needed to confirm the safety and efficacy of thrombectomy in broader populations, such as large core infarction and M2 occlusions.

Abstract 116: Predicting Symptomatic Intracranial Hemorrhage After Mechanical Thrombectomy: The TAG Score

Background: There is limited data on predictors of sICH in patients who underwent mechanical thrombectomy. In this study, we aim to determine those predictors with external validation.

Methods: We evaluated mechanical thrombectomy in a derivation cohort of patients at a comprehensive stroke center over a 30-month period. sICH was defined using the European Cooperative Acute Stroke Study III. We compared clinical and radiographic characteristics between patients with and without sICH to identify independent predictors of sICH with p<0.1. We then derived an sICH prediction score and validated it using the Blood Pressure After Endovascular Treatment (BEST) multicenter prospective registry.

Results: We identified 578 patients with acute ischemic stroke who received thrombectomy, 19 had sICH (3.3%). Predictive factors of sICH were: Thrombolysis in cerebral ischemia score, Alberta stroke program early computed tomography score (ASPECTS), and Glucose level, and using these predictors, we derived the weighted TAG score which was associated with sICH in the derivation (OR per unit increase 1.98, 95% CI 1.48-2.66, AUC=0.79) and validation (OR per unit increase 1.48, 95% CI 1.22-1.79, AUC=0.69) cohorts.

Conclusion: High TAG scores are associated with sICH in patients receiving mechanical thrombectomy. Larger studies are needed to validate this scoring system and test strategies to reduce sICH risk and make thrombectomy safer in patients with elevated TAG scores.

Abstract WP109: Redefining Early Neurological Improvement After Intravenous Tissue Plasminogen Activator Treatment of Stroke

Background and Purpose: Early neurologic improvement (ENI) in patients treated with alteplase has been shown to correlate with functional outcome. However, the definition of ENI remains controversial and has varied across studies. Current definitions take into account the absolute difference between the admission and 24-hour NIHSS but this difference is usually not reported as a function of the baseline NIHSS. We hypothesized that ENI defined as a percentage change in NIHSS (percent change NIHSS) at 24-hours would better correlate with favorable outcomes at 3 months than ENI defined as the change in NIHSS (delta NIHSS) at 24 hours.

Methods: Retrospective analysis of prospectively collected single center quality improvement data was performed of all acute ischemic stroke (AIS) patients treated with alteplase. Delta NIHSS was defined as the difference in admission and 24-hour NIHSS. Percent change NIHSS was defined as delta NIHSS divided by the admission NIHSS. We examined delta NIHSS and percent change NIHSS in unadjusted and adjusted logistic regression models as predictors of a favorable outcome at 3 months (defined as mRS 0-1).

Results: Among 586 patients with AIS treated with alteplase with admission NIHSS, 24-hour NIHSS, and 3-month mRS available, 194 (33.1%) had a favorable outcome at 3 months. The mean age was 65 years and 59% were men. In fully adjusted models, both delta NIHSS (OR per point decrease 1.27; 95% CI, 1.19– 1.36) and percent change NIHSS (OR per 10 percent decrease 1.17; 95% CI, 1.12-1.22) were associated with favorable functional outcome at 3 months. Receiver operating characteristic (ROC) curve comparison showed that the area under the ROC curve for percent change NIHSS (0.755) was greater than delta NIHSS (0.613) or admission NIHSS (0.694).

Conclusion: Percentage change in NIHSS may be a better surrogate marker of ENI and functional outcome in AIS patients after receiving acute thrombolytic therapy. More studies are needed to confirm our findings.

Abstract WP254: Insular Involvement of Ischemic Stroke Suggests a Cardioembolic Mechanism

Introduction: The insular cortex controls several aspects of vital function including autonomic regulation, and strokes affecting the insula have been associated with dysautonomia, cardiac dysfunction, and arrhythmias. Previous studies have shown an association between insular strokes, elevated troponin levels, and atrial fibrillation (AF). In this study, we aim to determine the association between cardiac biomarkers and insular involvement of the infarct and hypothesize that insular involvement implicates a cardioembolic source.

Methods: We abstracted data from a prospective comprehensive stroke center registry of consecutive patients with a discharge diagnosis of acute ischemic stroke who underwent brain imaging (CT or MRI) and work up to determine stroke mechanism. Data included demographics, clinical baseline variables, laboratory tests (including admission troponin level), and transthoracic echocardiographic variables (regional wall motion abnormalities, ejection fraction, and left atrial volume index), and stroke subtype. Multivariable logistic regression models were built to determine associations between AF, and cardiac biomarkers and insular infarcts.

Results: We identified 1224 patients who met the inclusion criteria; 397 (32.4%) had insular involvement of the infarct. In multivariable models, insular infarcts were associated with AF (adjusted OR 1.73, 95% CI 1.23-2.43, p = 0.001) and left atrial volume index (adjusted OR per standard deviation increase 1.30, 95% CI 1.13-1.49, p = 0.001). There was a trend for association between insular involvement and positive troponin level (adjusted OR 1.45 95% CI 0.91-2.33, p = 0.122) but not with regional wall motion abnormalities (adjusted OR 1.13, 95% CI 0.69-1.84, p = 0.627). Insular involvement was associated with cardioembolic stroke subtype (45.8% vs. 26.7%, p<0.001) but not other stroke subtypes.

Conclusion: The insular cortex is commonly involved in patients with atrial fibrillation and/or atrial dilation and maybe a neuroimaging biomarker of cardioembolic stroke. Larger studies are needed to confirm this association and test anticoagulation therapy in patients with insular infarcts.

Abstract WP411: Asymptomatic Hemorrhage Predicts Delayed Symptomatic Hemorrhage After Alteplase in Acute Ischemic Stroke

Background: Predictors of alteplase associated symptomatic intracranial hemorrhage (sICH) have been identified but there are very limited data on predictors of delayed sICH (> 24 hours from infusion). We hypothesize that asymptomatic hemorrhage on 24 hour brain imaging predicts delayed sICH and that delaying antithrombotic treatment in these patients reduces this risk.

Methods: This is a retrospective analysis of a prospective quality improvement database of a comprehensive stroke center. We included all patients with a discharge diagnosis of ischemic stroke who received alteplase. Patients with sICH occurring within 24 hours from alteplase and those whose code status was changed to comfort measures only were excluded. Delayed sICH was defined as any hemorrhage causing neurological deterioration. We compared baseline characteristics, asymptomatic hemorrhage on 24 hour brain imaging, and median time to initiating antithrombotic therapy between patients with and without delayed sICH.

Results: Among 606 patients who met our inclusion criteria; mean age was 70 years and 52% were men; 23.8% had asymptomatic hemorrhage on 24 hour brain imaging (CT or MRI) and 12 patients (2%) had delayed sICH. Aspirin was the most common initial antithrombotic (91.2%) followed by plavix (2.6%), and others (3.8%). After adjusting for confounders, asymptomatic hemorrhage on 24 hour brain imaging was associated with increased odds of delayed sICH (OR 5.5, 95% CI 1.52 - 19.87, p = 0.009) but the median time (days) to starting antithrombotic therapy did not differ between those with asymptomatic hemorrhage who developed delayed sICH vs. those who did not [2 (3) vs. 3 (5), p = 0.447).

Conclusion: Delayed sICH in patients receiving alteplase is uncommon and asymptomatic hemorrhage is a strong predictor. Delaying initiation of antithrombotic treatment in patients with asymptomatic hemorrhage on 24 hour imaging was not associated with reduced delayed sICH risk. It is possible that other factors such as reperfusion and blood brain barrier disruption are more important determinants of delayed sICH risk as opposed to timing of antithrombotic therapy initiation.

Abstract 166: Mechanical Thrombectomy in Ischemic Stroke Patients With Pre-Stroke Disability

Background: The current AHA/ASA guidelines recommend only offering mechanical thrombectomy (MT) to patients without pre-stroke disability. We aimed to compare outcomes of acute ischemic stroke patients with none-to-minimal (modified Rankin score, mRS, 0-1) and moderate (mRS 2-3) pre-stroke disability treated with MT.

Methods: Consecutive adult patients undergoing MT for an anterior circulation stroke were prospectively identified at two comprehensive stroke centers from 2012-2018. Procedural and 90-day functional outcomes were compared among patients with pre-stroke mRS 0-1 and 2-3 using Chi-squared, logistic, and linear regression tests and were adjusted for prespecified covariates.

Results: A total of 881 patients were included (mean age 70±16 years; 45% female) and 259 (29.4%) had moderate pre-stroke disability. Primary outcome of no accumulation of additional disability at 90 days was observed in 22.4% and 26.7% of patients with no-to-minimal and moderate pre-stroke disability, respectively (OR 1.27[0.88-1.81], p=0.2; adjusted OR 1.90[1.24, 2.94], p=0.004, Figure). Rate of symptomatic intracerebral hemorrhage (7.3% vs 6.2%, p=0.65), successful recanalization (86.7% vs 83.8%, p=0.33), and median length of hospital stay (5 vs 5 days, p=0.06) were not significantly different. Mean change in utility weighted mRS from baseline to 90 days was 0.35±0.35 in pre-stroke mRS 0-1 vs -0.38 ±0.32 in pre-stroke mRS 2-3, p=0.17. Death by 90-days was higher in patients with moderate pre-stroke disability (14.3% vs 40.3%, OR 4.06[2.82-5.86], p<0.001; adjusted OR 2.83[1.84, 4.37], p<0.001).

Interpretation: One-third of patients undergoing MT had a moderate pre-stroke disability. The odds of maintaining pre-stroke functional status at 90-days and procedural success rates were not different between patients with no-to-minimal and moderate pre-stroke disability. However, patients with pre-stroke disability were more likely to die by 90 days.

Abstract TP122: Peri-Procedural Stroke or Death in Stenting of Symptomatic Severe Intracranial Stenosis: A Post-Hoc Analysis of the SAMMPRIS Trial

Background and Purpose: There is limited data on predictors of 30-day stroke or death in patients with symptomatic intracranial atherosclerosis (sICAS) undergoing stenting. We aim to determine these predictors.

Methods: This is a post-hoc analysis SAMMPRIS including patients who underwent angioplasty/stenting. We determined associations between patient-specific, lesion-specific, and procedure-specific variables, and FDA-approved indications and the primary outcome (stroke or death at 30 days) using logistic regression analyses.

Results: We identified 213 patients; 30 patients (14.1%) met the primary outcome. The odds of stroke or death was higher with non-smokers vs. smokers (adjusted OR 4.46, 95% CI 1.79-11.1) and increasing lesion length in millimeters (adjusted OR 1.20, 95% CI 1.02-1.39). These had modest predictive value: absence of smoking history (sensitivity=66.7% and specificity=65.4%) and lesion length (Area Under Curve=0.606). Furthermore, event rates were not significantly different between patients with and without the FDA approved indication for stenting (15.9% vs. 12%, p = 0.437).

Conclusion: In SAMMPRIS patients who underwent angioplasty/stenting, neither clinical and neuroimaging variables nor the FDA indication for stenting reliably predicted the primary outcome. Further work in identifying reliable biomarkers of stroke/death in patients with sICAS is needed before considering new clinical trials of stenting.

Abstract TP341: Yield of Interval Magnetic Resonance Imaging in Determining Cryptogenic Etiologies of Spontaneous Intracerebral Hemorrhage

Introduction: Spontaneous intracerebral hemorrhage (ICH) most commonly arises due to primary etiologies such as hypertensive or cerebral amyloid angiopathy (CAA), but may also occur due to underlying secondary causes such as vascular malformations or intracranial neoplasms. However, focal mass effect may potentially obscure underlying lesions on neuroimaging performed during the acute phase of ICH, and follow-up imaging is often recommended. We sought to determine the yield of interval magnetic resonance imaging (MRI) in identifying cryptogenic ICH etiologies.

Methods: We performed a single-center descriptive cohort study of consecutive patients enrolled in an institutional ICH registry over 12 months. ICH features including etiology and acute neuroimaging were prospectively adjudicated, while planned interval follow-up imaging was retrospectively reviewed. We determined the frequency of newly-discovered findings on interval MRI, and classified new findings according to whether or not they contributed meaningfully to patient management.

Results: There were 241 ICH patients in our cohort who survived to discharge and did not have MRI-incompatible devices; 44 had planned follow-up imaging and 33 ultimately completed a follow-up MRI. Mean interval between initial and follow-up MRI was 61 (±34) days. New findings were identified in 33% of follow-up cases (11/33), with changes in patient management occurring in 12% (4/33). Age (59.4 vs. 61.5, p=0.74), sex (45% vs. 45% male, p>0.99), and secondary ICH score (median 3 [IQR 2-3] vs. 3 [1-4], p=0.87) were not significantly different between patients who had new findings and those who did not. New findings included cavernoma (n=4; 1 underwent resection), CAA-related changes (n=3), intracranial malignancy (n=2; 1 transitioned to hospice care, 1 led to cancer workup), new embolic stroke (n=1, underwent extended cardiac monitoring), and demyelination (n=1).

Conclusions: Interval MRI aided in diagnosing ICH etiology in one-third of patients who received one, though few cases led to direct actionable changes in patient management.

Abstract WP84: MRI Based Scores Outperform CTA Based Scores in Predicting Outcome After Basilar Artery Occlusion

Introduction: Clinical outcomes in patients with acute basilar occlusion (BAO) vary widely; several prognostic scores based on noninvasive imaging have been proposed. We aimed to compare the predictive value of several noninvasive neuroimaging scores in patients with BAO.

Methods: We performed a single-center retrospective cohort study including all patients with acute BAO from 2015-2019. Using available clinical radiographic data, we calculated the following scores based on computed tomography (CT) and CT angiogram: Goyal posterior communicating artery score, posterior circulation collateral score, Basilar Artery on Computed Tomography Angiography (BATMAN) score, pc-ASPECTS score, and pons-midbrain index. We also calculated the following scores based on diffusion-weighted (DWI) magnetic resonance imaging (MRI): Bern DWI score, MRI pc-ASPECTS, and pons-midbrain index on DWI. We then used logistic regression with area under the ROC curve analysis to determine the accuracy of each score in predicting favorable 3-month outcome (modified Rankin Scale 0-2).

Results: Of 39 patients in our cohort, 92.3% underwent endovascular treatment (n=36) and 35.8% (n=14) had a favorable 3-month outcome. The Bern DWI score (AUC 0.790, 95% CI 0.619-0.960), pc-ASPECTS on MRI (AUC 0.880, 95% CI 0.601-0.958), and pons-midbrain index on MRI (AUC 0.764, 95% CI 0.594-0.934) accurately predicted 3-month outcome when analyzed as raw scores (Figure 1).:

Conclusion: MRI scores more strongly predict outcome in BAO as compared to CTA collateral scores. Larger prospective studies are needed to confirm our findings.

Abstract TP222: Prevalence of Carotid Web in Patients With Cryptogenic Stroke

Introduction: Carotid web is a putative mechanism of cryptogenic ischemic stroke. We aimed to determine the prevalence of carotid web based on assigned stroke mechanism, and hypothesized that carotid webs would be found more frequently in younger cryptogenic stroke patients.

Methods: We performed a single-center retrospective cohort study using institutional registry data from consecutive patients with confirmed anterior circulation ischemic stroke between July 2015-September 2017. We reviewed all available computed tomography angiogram (CTA) studies of the neck, and excluded patients who did not have a high-quality CTA of the neck performed. Carotid web was defined as a thin shelf of non-calcified tissue protruding into the lumen of the internal carotid artery immediately distal to the bifurcation, best visualized on sagittal oblique imaging and evident as a small septum on axial imaging. Stroke subtype was adjudicated a priori using validated methods, and we compared relevant risk factors in patients with cryptogenic stroke with and without carotid web.

Results: We identified 882 patients with anterior circulation stroke who had a CTA neck available for review (49.3% male, 30% cryptogenic). A total of 7 patients (0.8%) were found to have carotid webs, of which 4 were ipsilateral to a patient’s stroke; all patients with ipsilateral carotid webs were adjudicated to have cryptogenic stroke. Patients with carotid web were younger than other patients in our cohort (age 49.0±14.6 vs. 72.2±14.9 years, p=0.003), and none of them had a history of hypertension (0% vs. 72%, p=0.04). In patients with cryptogenic stroke, overall prevalence of carotid webs was 1.5%, but the prevalence was significantly higher in younger cryptogenic stroke patients (age <60: 4.8%; age ≥60: 0.5%; p=0.01). Imaging findings that mimicked carotid webs, including non-calcified atherosclerosis and small protruding lesions, were prevalent in 8.3% of all patients.

Discussion: Carotid web may represent an under-recognized occult mechanism of cryptogenic stroke, particularly amongst younger patients.

Abstract WP128: Stroke Subtype Predicts Neurological Deterioration After Intravenous Alteplase for Acute Ischemic Stroke

Introduction: Intravenous alteplase improves functional outcome in patients with acute ischemic stroke. While patients often have better outcomes, other patients may experience recurrent or worsening symptoms. We sought to determine the association between stroke subtype and neurologic deterioration in this study cohort.

Methods: Data were abstracted from a prospective quality improvement registry at a comprehensive stroke center. Patients with symptomatic intracranial hemorrhage, no follow-up imaging, code status change to comfort measures only in the first 24 hours, or stroke mimics were excluded. Recurrent cerebrovascular events (RCVE) were defined as any new or worsening symptoms due to cerebral ischemia in the absence of intracranial hemorrhage or an alternative etiology such as infection or seizure. We compared demographic factors, vascular comorbidities, admission blood pressure, medications, use and timing of antithrombotics during hospitalization, admission NIH stroke scale, endovascular intervention, stroke subtype [Cardioembolic, large artery atherosclerosis, small vessel disease, cryptogenic, and other defined (such as dissection, hypercoagulability, cancer related, illicit drug use)], and good 90-day outcome (mRS 0-1) between the two groups using Fisher’s exact test and t-test as indicated. We then performed multivariable logistic regression analyses to determine associations between stroke subtypes and RCVE.

Results: We identified 705 patients treated with tPA, and 606 met the inclusion criteria. The rate of RCVE was 5.8% (35/606). In multivariable analyses, when compared to cardioembolic/cryptogenic stroke, RCVE was more common in small vessel disease (adjusted OR 9.51 p=0.029), large vessel disease (adjusted OR 5.60, p=0.033), and other stroke mechanisms (adjusted OR 11.29, p=0.019). RCVE was associated with more disability at 90 days when compared to non-RCVE (median mRS 4, IQR 3 vs. median mRS 3, IQR 2, p = 0.016).

Conclusions: Non-cryptogenic/Non-cardioembolic stroke subtypes are associated with early RCVE, and RCVE is associated with long term disability. Studies are needed to confirm our findings and test interventions optimizing stroke prevention strategies in these subtypes.

Abstract WMP70: Increased Left Atrial Appendage Density on Computerized Tomography is Associated With Cardioembolic Stroke

Background and Purpose: While studies have stratified cardioembolic (CE) stroke risk by qualitative left atrial appendage (LAA) morphology and biomarkers of atrial dysfunction, the quantitative properties that underlie these observations are not well established. Accordingly, we hypothesized that LAA volume and contrast density (attenuation) on computerized tomography (CT) may capture the structural and hemodynamic processes that underlie CE stroke risk.

Methods: Data were collected from a single center prospective ischemic stroke database over 18 months and included all patients with ischemic stroke who previously underwent routine, non-gated, contrast enhanced thin-slice (≤2.5 mm) chest CT. Stroke subtype was determined based on the inpatient diagnostic evaluation. LAA volume and attenuation were determined from CT studies performed for various clinically appropriate indications. Univariate and multivariable analyses were performed to determine factors associated with ischemic stroke subtype, including known risk factors and biomarkers, as well as LAA density and morphologic measures.

Results: We identified 311 patients with a qualifying chest CT (119 CE subtype, 109 ESUS, and 83 non-CE). In unadjusted models, there was an association between CE (vs. non-CE) stroke subtype and LAA volume (OR per mL increase 1.15, 95% CI 1.07-1.24, p<0.001) and LAA density (4 th quartile vs. 1 st quartile; OR 2.95, 95% CI 1.28-6.80, p=0.011), but not with ESUS (vs. non-CE) subtype. In adjusted models, only the association between LAA density and CE stroke subtype persisted (adjusted OR 3.71, 95% CI 1.37-10.08, p=0.010).

Conclusion: The LAA volume and density values on chest CT are associated with CE stroke subtype but not ESUS subtype. Patients with ESUS and increased LAA volume or attenuation may be a subgroup where the mechanism is cardioembolic and anticoagulation can be tested for secondary stroke prevention.

Predicting symptomatic intracranial haemorrhage after mechanical thrombectomy: the TAG score

BACKGROUND

There is limited data on predictors of symptomatic intracranial haemorrhage (sICH) in patients who underwent mechanical thrombectomy. In this study, we aim to determine those predictors with external validation.

METHODS

We evaluated mechanical thrombectomy in a derivation cohort of patients at a comprehensive stroke centre over a 30-month period. Clinical and radiographic data on these patients were obtained from the prospective quality improvement database. sICH was defined using the European Cooperative Acute Stroke Study III. We compared clinical and radiographic characteristics between patients with and without sICH using χ² and t tests to identify independent predictors of sICH with p<0.1. Significant variables were then combined in a multivariate logistic regression model to derive an sICH prediction score. This score was then validated using data from the Blood Pressure After Endovascular Treatment multicentre prospective registry.

RESULTS

We identified 578 patients with acute ischaemic stroke who received thrombectomy, 19 had sICH (3.3%). Predictive factors of sICH were: thrombolysis in cerebral ischaemia (TICI) score, Alberta stroke program early CT score (ASPECTS), and glucose level, and from these predictors, we derived the weighted TICI-ASPECTS-glucose (TAG) score, which was associated with sICH in the derivation (OR per unit increase 1.98, 95% CI 1.48 to 2.66, p<0.001, area under curve ((AUC)=0.79) and validation (OR per unit increase 1.48, 95% CI 1.22 to 1.79, p<0.001, AUC=0.69) cohorts.

CONCLUSION

High TAG scores are associated with sICH in patients receiving mechanical thrombectomy. Larger studies are needed to validate this scoring system and test strategies to reduce sICH risk and make thrombectomy safer in patients with elevated TAG scores.

Troponin Improves the Yield of Transthoracic Echocardiography in Ischemic Stroke Patients of Determined Stroke Subtype

Background and Purpose- Transthoracic echocardiography (TTE) is widely used in the ischemic stroke setting. In this study, we aim to investigate the yield of TTE in patients with ischemic stroke and known subtype and whether the admission troponin level improves the yield of TTE. Methods- Data were abstracted from a single-center prospective ischemic stroke database for 18 months and included all patients with ischemic stroke whose etiologic subtype could be obtained without the need of TTE. Unadjusted and adjusted regression models were built to determine whether positive cardiac troponin levels (≥0.1 ng/mL) improve the yield of TTE, adjusting for demographic and clinical characteristics. Results- We identified 578 patients who met the inclusion criteria. TTE changed clinical management in 64 patients (11.1%), but intracardiac thrombus was detected in only 4 patients (0.7%). In multivariable models, there was an association between TTE changing management and positive serum troponin level (adjusted odds ratio, 4.26; 95% CI, 2.17-8.34; P<0.001). Conclusions- In patients with ischemic stroke, TTE might lead to a change in clinical management in ≈1 of 10 patients with known stroke subtype before TTE but changed acute treatment decisions in <1 percent of patients. Serum troponin levels improved the yield of TTE in these patients.

Left Atrial Volume Index Is Associated With Cardioembolic Stroke and Atrial Fibrillation Detection After Embolic Stroke of Undetermined Source

Background and Purpose- Left atrial enlargement has been shown to be associated with ischemic stroke, but the association with embolic stroke mechanisms remains unknown. We aim to study the associations between left atrial volume index (LAVI) and embolic stroke subtypes and atrial fibrillation (AF) detection on cardiac event monitoring in patients with embolic stroke of unknown source. Methods- Data were collected from a prospective cohort of consecutive patients with ischemic stroke admitted to a comprehensive stroke center over 18 months. Stroke subtype was classified into cardioembolic stroke, noncardioembolic stroke of determined mechanism (NCE), or embolic stroke of undetermined source (ESUS). Univariate and prespecified multivariable analyses were performed to assess associations between LAVI and stroke subtype and AF detection in patients with ESUS. Results- Of 1224 consecutive patients identified during the study period, 1020 (82.6%) underwent transthoracic echocardiography and had LAVI measurements. LAVI was greater in patients with cardioembolic stroke than NCE (41.4 mL/m²±18.0 versus 28.6 mL/m²±12.2; P<0.001) but not in ESUS versus NCE (28.9 mL/m²±12.6 versus 28.6 mL/m²±12.2; P=0.61). In multivariable logistic regression models, LAVI was greater in cardioembolic stroke versus NCE (adjusted odds ratio per mL/m², 1.07; 95% CI, 1.05-1.09; P<0.001) but not in ESUS versus NCE (adjusted odds ratio per mL/m², 1.00; 95% CI, 0.99-1.02; P=0.720). Among 99 patients with ESUS who underwent cardiac monitoring, 18.2% had AF detected; LAVI was independently associated with AF detection in ESUS (adjusted odds ratio per mL/m², 1.09; 95% CI, 1.02-1.15; P=0.007). Conclusions- LAVI is associated with cardioembolic stroke as well as AF detection in patients with ESUS, 2 subsets of ischemic stroke that benefit from anticoagulation therapy. Patients with increased LAVI may be a subgroup where anticoagulation may be tested for stroke prevention.

Infarct Pattern, Perfusion Mismatch Thresholds, and Recurrent Cerebrovascular Events in Symptomatic Intracranial Stenosis

BACKGROUND AND PURPOSE

Studies have shown an association between infarct patterns and recurrent stroke in patients with symptomatic intracranial stenosis (sICAS) but there are limited data on associations with perfusion imaging mismatch profile. We aim to determine the association between infarct pattern, optimal mismatch profile definition, and recurrent cerebrovascular events (RCVE) in patients with anterior circulation sICAS.

METHODS

This is a retrospective study of consecutive patients with acutely sICAS admitted to a comprehensive stroke center over 18 month's period. Patients with sICAS underwent magnetic resonance perfusion (MRP) imaging within 24 hours from admission. Infarct patterns (internal BZ [IBZ], cortical BZ [CBZ], and core/perforator [C/P]) and RCVE within 90 days, were independently adjudicated by two reviewers. We compared mismatch profiles and recurrent event rates across infarct patterns.

RESULTS

Twenty-five patients met inclusion criteria; 28% had IBZ infarcts and overall RCVE rate was 32.0%. When compared to patients without IBZ infarcts, those with IBZ infarcts were more likely to have a target mismatch profile using T_max > 6 seconds (60% vs. 6.7%, P = .007) and RCVE (62.5% vs. 11.8%, P = .01). There were no associations between CBZ and C/P infarcts and target mismatch profiles and RCVE.

CONCLUSION

IBZ infarcts may be a surrogate marker of distal perfusion status and RCVE risk. Larger multicenter, prospective, core-lab blindly adjudicated studies are needed to confirm our findings.

The left atrial appendage morphology is associated with embolic stroke subtypes using a simple classification system: A proof of concept study

BACKGROUND AND PURPOSE

The current left atrial appendage (LAA) classification system (cLAA-CS) categorizes it into 4 morphologies: chicken wing (CW), windsock, cactus, and cauliflower, though there is limited data on either reliability or associations between different morphologies and stroke risk. We aimed to develop a simplified LAA classification system and to determine its relationship to embolic stroke subtypes.

METHODS

Consecutive patients with ischemic stroke from a prospective stroke registry who previously underwent a clinically-indicated chest CT were included. Stroke subtype was determined and LAA morphology was classified using the traditional system (in which CW = low risk) and a new system (LAA-H/L, in which low risk morphology (LAA-L) was defined as an acute angle bend or fold from the proximal/middle portion of the LAA and high risk morphology (LAA-H) was defined as all others). As a proof of concept study, we determined reliability for the two classification systems, and we assessed the associations between both classification systems with stroke subtypes in our cohort and previous studies.

RESULTS

We identified 329 ischemic stroke patients with a qualifying chest CT (126 cardioembolic subtype, 116 embolic stroke of undetermined source (ESUS), and 87 non-cardioembolic subtypes). Intra- and inter-rater agreements improved using the LAA-H/L (0.95 and 0.85, respectively) vs. cLAA-CS (0.50 and 0.40). The LAA-H/L led to classifying 69 LAA morphologies that met criteria for CW as LAA-H. In fully adjusted models, LAA-H was associated with cardioembolic stroke (OR 5.4, 95%CI 2.1-13.7) and ESUS (OR 2.8 95% CI 1.2-6.4). Non-CW morphology was also associated with embolic stroke subtypes, but the effect size was much less pronounced. Studies using the cLAA-CS yielded mixed results for inter- and intra-rater agreements but most showed an association between a non-CW morphology and stroke with no difference among the three non-CW subtypes.

CONCLUSION

The LAA-H/L classification system is simple, has excellent intra and inter-rater agreements, and may help risk identify patients with cardioembolic stroke subtypes. Larger studies are needed to validate these findings.

The Addition of Atrial Fibrillation to the Los Angeles Motor Scale May Improve Prediction of Large Vessel Occlusion

BACKGROUND AND PURPOSE

There is evidence suggesting that Los Angeles Motor Scale (LAMS) ≥ 4 predicts large vessel occlusion (LVO). We aim to determine whether atrial fibrillation (AF) can improve the ability of LAMS in predicting LVO.

METHODS

We included consecutive patients with a discharge diagnosis of ischemic stroke admitted within 24 hours from last known normal time who underwent emergent vascular imaging using a computerized tomography angiography (CTA) of the head and neck. LVO was defined as intracranial internal carotid artery, proximal middle cerebral artery (M1 or proximal M2 segment), or basilar occlusion. LAMS was determined in the emergency department upon arrival. Univariate and multivariable models were performed to identify predictors of LVO and to determine whether AF improves the ability of LAMS to predict LVO.

RESULTS

Among 1,234 patients admitted with ischemic stroke, 862 underwent emergent vascular imaging (69.8%) out of which 374 (43.4%) had evidence of LVO and 207 (24%) underwent mechanical thrombectomy. In multivariable models, predictors of LVO were LAMS (OR 1.42 per one point increase 95% CI 1.29-1.57) and AF (OR 1.95 95% CI 1.26-3.02, P < .001). We developed the LAMS-AF that includes the LAMS score and adds two points if AF is present. In this analysis, LAMS-AF (AUC .78) had improved prediction over LAMS (AUC .76) in predicting LVO and lead to reclassification of 8/68 patients (11.8%) with LAMS = 3 group into the high-risk LVO group.

CONCLUSION

In patients with LAMS = 3, using the LAMS-AF score may improve the ability of LAMS in predicting LVO. Larger studies are needed to confirm our findings.

Cardiac Biomarkers Predict Large Vessel Occlusion in Patients with Ischemic Stroke

BACKGROUND AND PURPOSE

Cardiac biomarkers may help identify stroke mechanisms and may aid in improving stroke prevention strategies. There is limited data on the association between these biomarkers and acute ischemic stroke (AIS) caused by large vessel occlusion (LVO). We hypothesized that cardiac biomarkers (cardiac troponin and left atrial diameter [LAD]) would be associated with the presence of LVO.

METHODS

Data were abstracted from a single center prospective AIS database over 18 months and included all patients with AIS with CT angiography of the head and neck. The presence of LVO was defined as proximal LVO of the internal carotid artery terminus, middle cerebral artery (M1 or proximal M2), or basilar artery. Univariate analyses and predefined multivariable models were performed to determine the association between cardiac biomarkers (positive troponin [troponin ≥0.1 ng/mL] and LAD on transthoracic echocardiogram) and LVO adjusting for demographic factors (age and sex), risk factors (hypertension, diabetes, hyperlipidemia, history of stroke, congestive heart failure, coronary heart disease, and smoking), and atrial fibrillation (AF).

RESULTS

We identified 1234 patients admitted with AIS; 886 patients (71.8%) had vascular imaging to detect LVO. Of those with imaging available, 374 patients (42.2%) had LVO and 207 patients (23.4%) underwent thrombectomy. There was an association between positive troponin and LVO after adjusting for age, sex and other risk factors (adjusted OR 1.69 [1.08-2.63], P = .022) and this association persisted after including AF in the model (adjusted OR 1.60 [1.02-2.53], P = 0.043). There was an association between LAD and LVO after adjusting for age, sex, and risk factors (adjusted OR per mm 1.03 [1.01-1.05], P = 0.013) but this association was not present when AF was added to the model (adjusted OR 1.01 [0.99-1.04], P = .346). Sensitivity analyses using thrombectomy as an outcome yielded similar findings.

CONCLUSIONS

Cardiac biomarkers, particularly serum troponin levels, are associated with acute LVO in patients with ischemic stroke. Prospective studies are ongoing to confirm this association and to test whether anticoagulation reduces the risk of recurrent embolism in this patient population.

Abstract WP74: Right Hemispheric Infarcts Have Higher CT Perfusion Penumbra Volume for Given NIH Stroke Scale: Results From BEST Prospective Cohort Study

Introduction: Right hemispheric strokes have a higher average infarct volume than left hemisphere strokes for the same severity of NIH stroke scale (NIHSS). This phenomenon, although well documented by CT and MRI based volume calculation of final infarct volume, is yet to be confirmed with automated acute CT/MR perfusion imaging in acute large vessel stroke setting. Additionally, penumbral volumes have not been well studied with regard to laterality of stroke.

Methods: Data from the BEST prospective cohort study, a multicenter study that enrolled consecutive patients with anterior cerebral large vessel occlusion undergoing endovascular treatment were used for analysis. We determined the correlation between baseline NIHSS and CTP penumbra volume (CTPp; total volume of Tmax>6sec) as well as core infarct volume (CTPc) for right sided and left sided strokes. We also determined the difference in CTPp and CTPc between right and left sided stroke for every 5-point increase in the baseline NIHSS.

Results: Of the 443 enrolled patients, 165 (82 female, median age 69 [IQR 57, 81]) had complete data for baseline CTPp and CTPc; one patient with bilateral strokes was excluded. Median CTPp for right sided (n=74) strokes was 127.5 cc [IQR 83, 167] and for left sided (n=90) strokes was 93.0 cc [IQR 62, 155]. Median CTPc for right sided strokes was 15.0 cc [IQR 0, 35] and that for left sided strokes was 6.5 cc [0, 24]. After adjusting for baseline NIHSS, right sided strokes had significantly higher CTPp than did left sided (p=0.001), but no evidence of laterality for CTPc was observed (p=0.09). The correlation coefficient for NIHSS and CTPp was 0.23 and 0.33, and that for CTPc was 0.16 and 0.19 for right and left side, respectively. Highest difference in CTPp between sides was observed at NIHSS 16-25 (table).

Conclusions: Right hemispheric strokes have higher CTPp but not CTPc as compared to the left. For a given NIHSS, right hemispheric strokes may have larger salvageable tissue.

Abstract 94: Blood Pressure After Endovascular Stroke Therapy (BEST): Final Results of a Prospective Multicenter Cohort Validation Study

Background: Limited data currently inform optimal post-endovascular therapy (EVT) blood pressure management. Systolic BP (SBP) >160 mmHg during the 24-hrs post-EVT correlated with worse outcomes in our retrospective multicenter study. To prospectively determine and potentially validate the specific post-EVT SBP threshold that discriminates functional outcomes, we designed a multicenter, prospective cohort study - “Blood Pressure after Endovascular Stroke Therapy (BEST)” - with a prespecified analysis plan.

Methods: Consecutive EVT-treated adult patients with ICA, M1, or M2 occlusions were enrolled at 12 comprehensive stroke centers, excluding those with disability, terminal diagnoses, LVAD, and in-hospital stroke. Baseline, treatment characteristics, and all SBP values during the 24 hrs post-EVT were captured. The primary outcome was 90d mRS (0-2 vs 3-6) adjusted for age, baseline NIHSS, glucose, ASPECTS, time to reperfusion, and history of hypertension. Secondary outcomes were intracerebral hemorrhage (ICH), symptomatic ICH, mRS distribution, and early neurologic recovery (ENR). A sample size of 340 was calculated to provide 80% power to detect a 1.36 odds ratio (i.e., 8% difference in mRS 3-6 rate) at α=0.05; inflated to 450 patients for up to 25% loss to follow up. The threshold of peak SBP that best discriminates mRS 0-2 vs. 3-6 will be identified with Youden’s index, and its association with outcomes will be quantified using logistic regression. Subgroup analysis by mTICI score and associations of other BP parameters with outcomes will be explored. Missing 90d outcomes will be imputed.

Results: We enrolled 457 patients from 11/2017 to 7/2018 with mean age 68y (±15), 52% females, median NIHSS 16 (IQR 11,20), and ASPECTS 8 (IQR 7,10). 221 (48%) patients received alteplase and 402 (88%) achieved mTICI 2b-3. Mean peak SBP was 165±24 mmHg in mTICI2b-3 group and 171±22 in mTICI 0-2a group, and 352 (77%) received an IV antihypertensive. 331 (73%) patients have outcomes available at 90d; rest are expected by 10/2018. Final results will be presented at ISC.

Conclusion: Expected results from BEST will inform clinical care and guide a developing randomized trial of targeted antihypertensive treatment in EVT-treated stroke patients.

Abstract WP263: Wall Motion Abnormalities on Transthoracic Echocardiography in the Setting of Ischemic Stroke Reflect Underlying Cardiac Disease and May Warrant an Ischemic Cardiac Evaluation

Background and Purpose: Patients with acute ischemic stroke (AIS) are at a heightened risk of cardiovascular events. We hypothesize that wall motion abnormalities (WMA) on transthoracic echocardiography (TTE) in the setting of AIS reflect underlying heart disease rather than reversible cardiac strain caused by the stroke.

Methods: Data was abstracted from a single center prospective AIS database over 18 months and included all patients with acute ischemic stroke who underwent a TTE. The presence of WMA was abstracted from the TTE report. Univariate analyses and predefined multivariable models were performed to determine factors associated with WMA, including demographic factors (age and sex), risk factors (hypertension, diabetes, hyperlipidemia, history of stroke, atrial fibrillation, congestive heart failure, coronary heart disease, and smoking), NIHSS score, cardiac markers (positive troponin, ECG evidence of prior myocardial infarction, ejection fraction), and insular location of infarct.

Results: We identified 1044 patients who met the inclusion criteria; 139 (13.3%) had evidence of WMA, of which only 23 patients had no history of heart disease or ECG evidence of prior myocardial infarction. Among these 23 patients, 12 had a follow up TTE after the stroke and WMA persisted in 92.7% (11/12) of patients. On fully adjusted models, factors associated with WMA are older age (OR per SD 1.03, 95% CI 1.001-1.05; p=0.009), congestive heart failure (OR 4.44, 95% CI 2.39-8.33, p<0.001), history of coronary artery disease or ECG evidence prior myocardial infarction (OR 27.03, 95% CI 14.93-50.0, p<0.001), and elevated serum troponin levels (OR 2.00, 95% CI 1.06-3.75, p=0.031).

Conclusion: In AIS patients, WMA on TTE may reflect underlying cardiac disease and warrant further cardiovascular evaluation particularly in those without known history of cardiac disease. Future studies are needed to investigate the cost-effectiveness of this approach.

Abstract TP98: Diabetes Mellitus Predicts Symptomatic Intracerebral Hemorrhage Following Thrombectomy in Acute Ischemic Stroke

Introduction: Diabetes mellitus has deleterious effects on blood vessel integrity via several mechanisms including blood brain barrier injury, excitatory chemokines, acidosis, and edema. It has been associated with symptomatic intracerebral hemorrhage (sICH) after alteplase administration for ischemic stroke. We aim to determine the association between diabetes and sICH in patients undergoing thrombectomy.

Methods: Data was abstracted from the Rhode Island Hospital prospective stroke registry and included consecutive patients who were selected for thrombectomy at our institution over a period of 24 months with the goal of identifying risk factors for sICH. The primary predictor was history of diabetes and the primary outcome was sICH defined based on the modified SITS-MOST criteria (parenchymal hematoma along with increase in NIHSS by 4 points or more). We compared baseline characteristics between patients with and without sICH using univariate and multivariable analyses. Statistical analysis was performed using SPSS version 20.0 and a p value of <0.05 was statistically significant.

Results: Out of 307 patients, 12 (3.9%) experienced sICH. The mean age was 73 years; 49.2% were men. On univariate analyses, diabetes mellitus was associated with sICH (50.0% vs. 17.3%, p= 0.012). This association persisted on multivariable models adjusting for age, NIHSS score, ASPECTS score, time to reperfusion, and TICI score (Odds Ratio 6.0, 95% CI 1.5-23.3, p=0.011). We performed sensitivity analyses excluding patients who received intravenous tPA (n = 189) and the results remained unchanged (OR 8.5, 95% CI 0.84-83.3, p = 0.071).

Conclusion: Diabetes mellitus is an independent predictors of sICH in patients with acute ischemic stroke undergoing mechanical thrombectomy, with or without IV tPA. More studies are needed to confirm our findings and to determine blood sugar control in the post-thrombectomy reduces this risk.

Abstract WMP3: DEFUSE-3 Eligible but DAWN Ineligible Patients Treated Within 16-24 Hours: Results From BEST Prospective Cohort Study

Background: The 2018 ASA guidelines recommend endovascular stroke treatment (EVT) for patients who meet DEFUSE 3 (D3) trial criteria within 6-16 hrs and those who meet DAWN criteria within 6-24 hrs of last known well (LKW). Recommendation to use more restrictive DAWN and not D3 criteria between 16 and 24 hrs is not strictly followed in clinical practice. Using the prospective multi-institutional cohort study, “Blood Pressure after EVT (BEST),” we determined the frequency and outcomes of EVT-treated patients within the 16-24 hrs of LKW who met D3 but not DAWN criteria.

Methods: BEST enrolled consecutive EVT-treated adult patients with ICA, M1, or M2 occlusions at 12 comprehensive stroke centers from 11/2017 to 7/2018. D3-but not DAWN-eligible patients were defined as those with ICA/M1 occlusions, a mismatch volume 15cc, and any of the following: 1) NIHSS 6-9, 2) infarct core 51-70 cc, 3) age 80 yrs and infarct core 21-70 cc, or 4) NIHSS 11-19 , age <80 yrs and infarct core 31-70 cc. We compared mTICI score, symptomatic ICH, discharge disposition, and 90-day mRS in patients who met D3 but not DAWN criteria (16-24 hrs) to those who strictly met criteria for 1) D3 (6-16 hrs) and 2) DAWN (6-24 hrs).

Results: Of 457 patients, 159 (35%) underwent EVT within 6-24 hrs (mean age 66 yrs; 51% female; median NIHSS 14 [IQR: 9, 19]), and 26 (16%) were within 16-24 hrs. Of the 16-24 hr group, 8 (31%) met D3 but not DAWN criteria. Proportion of mTICI 2b-3, symptomatic ICH, and discharge disposition distribution were not different compared those who met full D3 or DAWN criteria. 90-day functional outcomes were better than those who met the full DAWN criteria (table).

Conclusion: One in three patients treated with EVT within 16-24 hrs of LKW at major academic comprehensive stroke centers did not meet current guideline recommendations (DAWN criteria). In this small sample size study, safety and outcome results are comparable to those who met guideline criteria. Dedicated studies are needed to confirm this finding.

Abstract WP86: What Threshold Defines Penumbral Brain Tissue in Patients With Symptomatic Anterior Circulation Intracranial Stenosis: An Exploratory Analysis

Background: Impaired distal perfusion predicts neurological deterioration in patients with large artery atherosclerosis. We aim to determine the optimal threshold of T max delay on perfusion imaging associated with neurological deterioration in patients with symptomatic proximal anterior circulation large artery stenosis.

Methods: Data were abstracted from a prospective ischemic stroke database of consecutively enrolled patients with symptomatic proximal intracranial stenosis (internal carotid artery or M1 segment of the middle cerebral artery) who underwent magnetic resonance perfusion imaging within 24 hours of symptom onset during a 15 month period. Tissue volumes of perfusion delay T max 0-4 seconds, T max > 4 seconds, T max > 6 seconds, and T max > 8 seconds were calculated using an automated approach. A target mismatch (penumbra - core) was defined as ≥ 15 mL of brain tissue using each of the T max threshold categories. The outcome was neurological deterioration at 30 days defined as new or worsening neurological deficits that are not attributed to a non-vascular etiology.

Results: Among 52 patients with symptomatic intracranial stenosis, 26 patients met inclusion criteria. Neurological deterioration was associated with target mismatch profile defined according to T max >6 [66.7% (6/9) vs. 5.9% (1/17), p <0.01) and T max >8 [57.1% (4/7) vs. 15.8% (3/19), p = 0.05] but not T max >4 [27.3% (6/17) vs. 11.1% (1/9), p = 0.35].

Conclusion: A target mismatch profile using T max > 6 sec may optimally define tissue at risk in patients with symptomatic proximal intracranial stenosis. Larger prospective multicenter studies are needed to confirm our findings.