Artery of Percheron Infarction: Clinical Presentation and Outcomes

Background and Objectives

Occlusion of the artery of Percheron (AOP) produces bilateral thalamic infarction classically leading to deficits of arousal. This nonspecific presentation complicates the diagnosis of acute ischemic stroke. We sought to describe the spectrum of clinical presentation, diagnostic neuroimaging findings, and outcomes in AOP infarction (AOPi).

Methods

We conducted a keyword search of our health system's neuroimaging database from 2014 to 2022 to identify patients with AOPi. We abstracted patient demographics, clinical presentation, neuroimaging findings, acute treatment, and modified Rankin Scale (mRS) scores (at baseline, 3 months, and 12 months). We used descriptive statistics to report our findings.

Results

Our initial keyword search identified 192 potential AOPi cases. Fifteen cases of AOPi were confirmed and included in our study (8 female [53%], median age 65 years [interquartile range (IQR): 59.5-79.5], median presenting NIHSS 6 [IQR: 2-22]). Common clinical findings on presentation were systolic blood pressure (SBP) > 140: 12 patients (80%); decreased level of consciousness (LOC): 11 patients (73%); diplopia: 8 patients (57%); disorientation: 6 patients (42%); dysarthria: 4 patients (28%); and acute memory/cognitive disturbance: 3 patients (21%). Twelve cases (80%) presented to the emergency department (ED). Median time from symptom onset to ED arrival was 774.5 minutes (IQR: 202.25-3789.0), 4 cases (27%) arrived within 4.5 hours, and one patient (7%) received intravenous thrombolysis. The median time from ED arrival to stroke diagnosis was 519.0 minutes (IQR: 227.5-1307). Head CT was only diagnostic when obtained >570 minutes from time last known well; MRI was diagnostic at all time points. Rates of functional independence (mRS ≤2) at baseline, 3 months, and 12 months were 64%, 21%, and 18%, respectively.

Discussion

The diagnosis of stroke was considerably delayed in patients with AOPi, and only one patient received IV thrombolysis. SBP >140, impaired consciousness, and diplopia were the most common findings at presentation. CT was often nondiagnostic, but MRI demonstrated bilateral thalamic infarct in all cases. AOPi caused considerable long-term morbidity. Clinicians should maintain a high degree of suspicion for AOP stroke and consider thrombolysis in appropriately selected patients.

Tenecteplase for Stroke at 4.5 to 24 Hours with Perfusion-Imaging Selection

BACKGROUND

Thrombolytic agents, including tenecteplase, are generally used within 4.5 hours after the onset of stroke symptoms. Information on whether tenecteplase confers benefit beyond 4.5 hours is limited.

METHODS

We conducted a multicenter, double-blind, randomized, placebo-controlled trial involving patients with ischemic stroke to compare tenecteplase (0.25 mg per kilogram of body weight, up to 25 mg) with placebo administered 4.5 to 24 hours after the time that the patient was last known to be well. Patients had to have evidence of occlusion of the middle cerebral artery or internal carotid artery and salvageable tissue as determined on perfusion imaging. The primary outcome was the ordinal score on the modified Rankin scale (range, 0 to 6, with higher scores indicating greater disability and a score of 6 indicating death) at day 90. Safety outcomes included death and symptomatic intracranial hemorrhage.

RESULTS

The trial enrolled 458 patients, 77.3% of whom subsequently underwent thrombectomy; 228 patients were assigned to receive tenecteplase, and 230 to receive placebo. The median time between the time the patient was last known to be well and randomization was approximately 12 hours in the tenecteplase group and approximately 13 hours in the placebo group. The median score on the modified Rankin scale at 90 days was 3 in each group. The adjusted common odds ratio for the distribution of scores on the modified Rankin scale at 90 days for tenecteplase as compared with placebo was 1.13 (95% confidence interval, 0.82 to 1.57; P = 0.45). In the safety population, mortality at 90 days was 19.7% in the tenecteplase group and 18.2% in the placebo group, and the incidence of symptomatic intracranial hemorrhage was 3.2% and 2.3%, respectively.

CONCLUSIONS

Tenecteplase therapy that was initiated 4.5 to 24 hours after stroke onset in patients with occlusions of the middle cerebral artery or internal carotid artery, most of whom had undergone endovascular thrombectomy, did not result in better clinical outcomes than those with placebo. The incidence of symptomatic intracerebral hemorrhage was similar in the two groups. (Funded by Genentech; TIMELESS ClinicalTrials.gov number, NCT03785678.).

Tenecteplase for Acute Ischemic Stroke Thrombolysis: Practical Considerations and Real-World Implementation

The only FDA-approved medical treatment for acute ischemic stroke (AIS) is alteplase (commonly referred to as "tPA"). The utilization of a newer fibrinolytic agent, tenecteplase, in routine stroke care is increasing because of recent clinical trial findings, streamlined clinical workflows, and cost-effectiveness. The stroke community is monitoring this development with considerable interest and special attention to the following questions: (1) Does the current evidence support superiority or noninferiority of tenecteplase compared with standard-of-care alteplase? (2) What are the ramifications of off-label treatment with tenecteplase? (3) And what are the real-world considerations when transitioning from alteplase to tenecteplase for AIS thrombolysis? This commentary provides a practical synthesis of the current evidence and discusses our institutional experience with tenecteplase including treatment considerations, off-label use, patient consent, stroke center accreditation, and cost savings. Necessary "Code Stroke" workflow changes to ensure a safe transition from alteplase to tenecteplase are detailed.

Acute Amnestic Syndrome and Ischemic Stroke: A Case Series

Purpose of Review

Stroke is an uncommon cause of amnesia. We describe in detail 3 cases of anterograde amnesia and confabulation secondary to acute ischemic stroke and review the available literature.

Recent Findings

In our case series, all 3 patients presented with anterograde amnesia and 2 of 3 copresented with prominent confabulation. These symptoms were recognized in delayed fashion, and no patients received IV tissue plasminogen activator (tPA). Although stroke infarct topology was variable, all 3 patients had infarction of the fornix. Long-term follow-up was obtained in 2 of 3 patients: both had persistent memory impairment and were no longer functionally independent.

Summary

Acute onset anterograde amnesia and confabulation may uncommonly represent acute ischemic stroke. Delays in this diagnosis typically exclude patients from emergent stroke treatment or timely diagnostic stroke evaluation. Clinicians should maintain a high degree of suspicion for ischemic stroke in this setting, especially in patients with comorbid vascular risk factors. Memory impairment secondary to ischemic stroke can produce considerable long-term disability.

Abstract P296: Utility of Routine Transfer for Patients Administered Intravenous Alteplase for Ischemic Stroke

Introduction: Intravenous Alteplase is currently the only approved medical therapy for treatment of acute ischemic stroke (AIS). Although complications are uncommon, AIS patients receiving IV Alteplase are routinely transferred to higher level stroke centers for monitoring. This resource intensive treatment paradigm is of unclear medical benefit.

Methods: We reviewed the stroke thrombolysis database of a single comprehensive stroke center. All presumed AIS patients who received IV Alteplase without thrombectomy from 01/01/2015 to 12/31/2019 were included. Baseline demographics including age, sex, race, ethnicity, comorbidities, and NIHSS were abstracted. Complication rates including angioedema, intracranial and extracranial hemorrhage were recorded. To determine the utility of routine transfer, medical and surgical/neurosurgical interventions to treat complications of Alteplase administration were studied. Complication rates in the transfer and non-transfer cohorts were compared via Fischer’s exact test.

Results: Three hundred eighteen patients were reviewed and 222 consecutive AIS patients (median age 67 [IQR 55.5-77], female 48.6%, median NIHSS 5 [IQR 2-10], transfers 54.5%) were eligible for our analysis. Complication rates were not statistically different between transfer and non-transfer patients. Four (1.8%) patients suffered symptomatic intracranial hemorrhage (sICH). All sICH patients received cryoprecipitate and aggressive blood pressure management; none underwent emergent neurosurgical intervention.

Conclusion: The overall rate of complications post-Alteplase administration for AIS patients was similarly low between transfer and non-transfer patients. These findings call into question the utility of routine transfer of AIS patients treated with Alteplase. Further study of alternative post-Alteplase monitoring strategies, including remote specialist management via telemedicine, should be considered.

Exploratory study of how Cognitive Multisensory Rehabilitation restores parietal operculum connectivity and improves upper limb movements in chronic stroke

Cognitive Multisensory Rehabilitation (CMR) is a promising therapy for upper limb recovery in stroke, but the brain mechanisms are unknown. We previously demonstrated that the parietal operculum (parts OP1/OP4) is activated with CMR exercises. In this exploratory study, we assessed the baseline difference between OP1/OP4 functional connectivity (FC) at rest in stroke versus healthy adults to then explore whether CMR affects OP1/OP4 connectivity and sensorimotor recovery after stroke. We recruited 8 adults with chronic stroke and left hemiplegia/paresis and 22 healthy adults. Resting-state FC with the OP1/OP4 region-of-interest in the affected hemisphere was analysed before and after 6 weeks of CMR. We evaluated sensorimotor function and activities of daily life pre- and post-CMR, and at 1-year post-CMR. At baseline, we found decreased FC between the right OP1/OP4 and 34 areas distributed across all lobes in stroke versus healthy adults. After CMR, only four areas had decreased FC compared to healthy adults. Compared to baseline (pre-CMR), participants improved on motor function (MESUPES arm p = 0.02; MESUPES hand p = 0.03; MESUPES total score p = 0.006); on stereognosis (p = 0.03); and on the Frenchay Activities Index (p = 0.03) at post-CMR and at 1-year follow-up. These results suggest enhanced sensorimotor recovery post-stroke after CMR. Our results justify larger-scale studies.

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.

Noncontrast CT versus Perfusion-Based Core Estimation in Large Vessel Occlusion: The Blood Pressure after Endovascular Stroke Therapy Study

BACKGROUND AND PURPOSE

The 2018 AHA guidelines recommend perfusion imaging to select patients with acute large vessel occlusion (LVO) for thrombectomy in the extended window. However, the relationship between noncontrast CT and CT perfusion imaging has not been sufficiently characterized >6 hours after last known normal (LKN).

METHODS

From a multicenter prospective cohort of consecutive adults who underwent thrombectomy for anterior LVO 0-24 hours after LKN, we correlated baseline core volume (rCBF < 30%) and the Alberta Stroke Program Early CT Scale (ASPECTS) score. We compared perfusion findings between patients with an unfavorable ASPECTS (<6) against those with a favorable ASPECTS (≥6), and assessed findings over time.

RESULTS

Of 485 enrolled patients, 177 met inclusion criteria (median age: 69 years, interquartile range [IQR: 57-81], 49% female, median ASPECTS 8 [IQR: 6-9], median core 10 cc [IQR: 0-30]). ASPECTS and core volume moderately correlated (r = -.37). A 0 cc core was observed in 54 (31%) patients, 70% of whom had ASPECTS <10. Of the 28 patients with ASPECTS <6, 3 (11%) had a 0 cc core. After adjustment for age and stroke severity, there was a lower ASPECTS for every 1 hour delay from LKN (cOR: 0.95, 95% confidence of interval [CI]: 0.91-1.00, P = .04). There was no difference in core (P = .51) or penumbra volumes (P = .87) across patients over time.

CONCLUSIONS

In this multicenter prospective cohort of patients who underwent thrombectomy, one-third of patients had normal CTP core volumes despite nearly three quarters of patients showing ischemic changes on CT. This finding emphasizes the need to carefully assess both noncontrast and perfusion imaging when considering thrombectomy eligibility.

Blood Pressure after Endovascular Therapy for Ischemic Stroke (BEST): A Multicenter Prospective Cohort Study

Background and Purpose- To identify the specific post-endovascular stroke therapy (EVT) peak systolic blood pressure (SBP) threshold that best discriminates good from bad functional outcomes (a priori hypothesized to be 160 mm Hg), we conducted a prospective, multicenter, cohort study with a prespecified analysis plan. Methods- Consecutive adult patients treated with EVT for an anterior ischemic stroke were enrolled from November 2017 to July 2018 at 12 comprehensive stroke centers accross the United States. All SBP values within 24 hours post-EVT were recorded. Using Youden index, the threshold of peak SBP that best discriminated primary outcome of dichotomized 90-day modified Rankin Scale score (0-2 versus 3-6) was identified. Association of this SBP threshold with the outcomes was quantified using multiple logistic regression. Results- Among 485 enrolled patients (median age, 69 [interquartile range, 57-79] years; 51% females), a peak SBP of 158 mm Hg was associated with the largest difference in the dichotomous modified Rankin Scale score (absolute risk reduction of 19%). Having a peak SBP >158 mm Hg resulted in an increased likelihood of modified Rankin Scale score 3 to 6 (odds ratio, 2.24 [1.52-3.29], P<0.01; adjusted odds ratio, 1.29 [0.81-2.06], P=0.28, after adjustment for prespecified variables). Conclusions- A peak post-EVT SBP of 158 mm Hg was prospectively identified to best discriminate good from bad functional outcome. Those with a peak SBP >158 had an increased likelihood of having a bad outcome in unadjusted, but not in adjusted analysis. The observed effect size was similar to prior studies. This finding should undergo further testing in a future randomized trial of goal-targeted post-EVT antihypertensive treatment.

Reduced Intracerebral Hemorrhage and Perihematomal Edema Volumes in Diabetics on Sulfonylureas

Background and Purpose—

Sulfonylurea medications have been linked to reduced brain edema and improved outcome following ischemic stroke, but their effects on primary intracerebral hemorrhage (pICH) have not been thoroughly explored. Increasing ICH volume and perihematomal edema (PHE) volume are predictors of poor outcome in pICH. We investigated whether preexisting sulfonylurea use influenced ICH volume, PHE volume, and discharge disposition in patients with type 2 diabetes mellitus presenting with pICH.

Methods—

We performed a retrospective chart review of all diabetic patients presenting with pICH to 2 tertiary academic centers from 2006 to 2016. All patients with diabetes mellitus, pICH, admission computed tomography scan, and sulfonylurea use on admission were included in our study. For each case, 2-matched controls (admission date, age, hematoma location [deep versus lobar], use of antiplatelet, or anticoagulant) with diabetes mellitus and pICH were consecutively selected. ICH and PHE volumes were measured via region of interest analysis on admission computed tomography. To mitigate the influence of ICH volume on PHE, the PHE/ICH surface area ratio was calculated. Hospital discharge disposition was determined via chart abstraction. We used the Wilcoxon rank-sum test and Fisher exact test to compare cases and controls.

Results—

Of 317 patients screened, 21 sulfonylurea cases and 42-matched controls met criteria for study inclusion. Sulfonylurea cases had significantly lower admission ICH volumes (median, 4 mL; interquartile range [IQR], 2–30 versus median, 25 mL; IQR, 6–60; P =0.011), PHE volumes (median, 4 mL; IQR, 0.9–24 versus median, 17; IQR, 6–37; P =0.0095), and PHE/ICH surface area ratios (median, 0.28; IQR, 0.1–0.4 versus median, 0.43; IQR, 0.3–0.6; P =0.013) as compared with controls. Sulfonylureas were associated with improved discharge disposition ( P =0.0062).

Conclusions—

In patients with diabetes mellitus and pICH, sulfonylurea use predicted lower ICH and PHE volumes, lower relative PHE, and improved discharge disposition. Given the paucity of treatment options for pICH, further study of sulfonylureas is warranted.

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 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 WMP21: Underestimation of Ischemic Core on Perfusion CT in Patients With Acute Large Vessel Occlusion: Results From the BEST Prospective Cohort Study

Background: The 2018 AHA guidelines recommend patients with acute large vessel occlusion (LVO) be considered for thrombectomy in the 6 to 24-hour window based on perfusion imaging. Within 6 hours, CT perfusion (CTP) core estimates may underestimate volume of irreversible infarction visualized on the unenhanced CT; however this has not been well characterized in later time windows.

Methods: Using a multi-center prospective cohort of consecutive patients who underwent thrombectomy for LVO 0-24 hours after last known normal, we correlated baseline CTP core infarct volume (rCBF<30%) and unenhanced CT ASPECTS score, as recorded by local investigators. We compared CTP findings between patients with an unfavorable ASPECTS (<6) against those with a favorable ASPECTS (≥6), and assessed findings over time.

Results: Of 443 enrolled patients, 165 who underwent CTP were included (median age 69y [IQR 57-80], 83 [50%] female, with a median ASPECTS of 8 [IQR 6-9] and core of 9cc [IQR 0-28]). ASPECTS and core volume moderately correlated (r=-0.35, p<0.01). An absent core (0cc) was observed in 52/165 (32%) patients, among whom the median ASPECTS score was 8 (IQR 8-10). Of the 28 patients with unfavorable ASPECTS, 3 had a normal core volume (11%, 95%CI 2 - 28%). As time to recanalization progressed, the ASPECTS score worsened (common OR 1.05, 95%CI 1.01-1.09, p=0.02) whereas the core (p=0.66) and penumbra volumes (p=0.70) remained unchanged. After adjustment for age and baseline NIHSS, the decline in ASPECTS remained significant (cOR 1.05, 95%CI 1.01-1.10, p=0.01), while the core (p=0.69) and penumbra volumes (p=0.74) remained unchanged.

Conclusion: In this multi-center prospective cohort of patients who underwent thrombectomy, one-third of patients had normal core infarct volumes despite half of these patients showing irreversible infarction on the unenhanced CT (ASPECTS ≤8). As time progresses, the unenhanced CT demonstrates evolution of irreversible infarction, whereas the perfusion core appears static. This finding emphasizes the need to carefully assess both unenhanced CT and CTP when considering thrombectomy eligibility in the late time window, as was required by both DAWN and DEFUSE 3 selection criteria.

Abstract 110: Pre-Endovascular Therapy Change in BP is Associated With Outcome: A post-Hoc Analysis of the Blood Pressure After Endovascular Treatment (BEST) Prospective Cohort Study

Background: Higher blood pressure on admission is associated with worse outcomes in stroke patients undergoing endovascular therapy (EVT). However, if BP changes pre-EVT affects outcomes remains unknown. We sought to determine this association in the prospective multi-institutional cohort study, Blood Pressure after EVT in Stroke (BEST).

Methods: We enrolled consecutive adult patients in BEST with acute ischemic stroke who underwent clot retrieval from ICA, M1, or M2 from Nov 2017 to May 2018 at 12 comprehensive stroke centers. Study variables included change in mean arterial pressure (MAP) from admission to immediately pre-EVT. Primary outcomes was dichotomous 90-day modified Rankin score [mRS] 0-2 (good outcome) vs. 3-6 (bad outcome). We determined the association between any decrease or increase in MAP (delta MAP = Pre-EVT MAP – Admission MAP) and poor outcome (defined by mRS 0-2) using univariate and multivariable analysis (adjusted for age, NIHSS score, TICI score, and time to reperfusion).

Results: Among 443 patients, 218 patients had data on pre-EVT BP (missing: n = 61) and 90-day mRS (missing: n = 164). The mean age was 68.8±14.6; 52.3% were women; median NIHSS was 16.5 (IQR 12-21). Baseline characteristics and outcomes are reported in table 1. In multivariable models, each mmHg increase or decrease in MAP was associated with higher odds of worse outcome (OR 1.05, 95% CI 1.002-1.10, p=0.042 and OR 1.06, 95% CI 1.01-1.11, p=0.021, respectively). (Table 2)

Conclusion: We found a “U” shape association between pre-EVT change in MAP and poor outcome (Figure). While a drop in MAP may lead to infarct growth, an increase in MAP maybe a sign of failing collaterals and worsening ischemia. Future studies are needed to determine the best BP target pre-endovascular treatment.

Abstract 109: Thrombectomy is Safe for Dawn- and Defuse-3-Ineligible Patients Who Present Within the Extended Window: A Subgroup Analysis From the BEST Prospective Cohort Study

Background: Recent data have demonstrated robust efficacy for endovascular thrombectomy in acute large vessel occlusion (LVO) up to 24h after symptom onset. Given the overwhelming benefit of this intervention in a highly selective, clinical trial population, it is plausible that a benefit may also be observed in some trial-ineligible patients.

Methods: Using the BEST multi-center prospective cohort of consecutive patients who underwent thrombectomy for LVO, we compared DAWN and DEFUSE 3 trial-ineligible patients treated within 6-24 hours after last known normal (LKN) to trial-eligible patients, and to untreated controls from those trials. The co-primary outcomes were an early therapeutic response (decrease in NIHSS ≥10, or NIHSS 0-1 by 24h) and good functional outcome (90-day mRS 0-2). Secondary outcomes included change in NIHSS at 24h, intracerebral hemorrhage within 72h, and discharge to home or acute rehab.

Results: Of 443 patients in the BEST cohort, 159 (36%) underwent endovascular therapy between 6-24 hours after LKN, of whom 71 (45%) were trial-ineligible. The most common trial exclusion criteria were M2 (53%) and multivessel occlusions (30%). Compared to trial-eligible patients, trial-ineligible patients were younger (median 63 vs. 72y, p=0.02) but had similar baseline NIHSS (median 14 vs. 15, p=0.28), ASPECTS scores (median 8 v. 8, p=0.69), times to recanalization (median 627 vs. 682 min, p=0.08), and rates of successful recanalization (TICI 2b/3, 83% v. 86%, p=0.57). Compared to DAWN untreated controls, BEST trial-ineligible patients were more likely to have an early therapeutic response (OR 2.02, 95%CI 1.00-4.06, p=0.049) and good functional outcome (OR 3.02, 95%CI 1.33-6.86, p=0.001). Compared to trial-eligible patients in BEST, trial-ineligible patients had similar improvements in 24h NIHSS (-2 vs. -4, p=0.33), rates of intracerebral hemorrhage (28% vs. 24%, p=0.54), and rates of discharge to home or rehab (77% vs. 73%, p=0.49).

Conclusion: This multicenter prospective cohort demonstrates that thrombectomy for acute LVO within 24 hours in DAWN and DEFUSE 3 trial-ineligible patients is safe and may be effective. Treating these patients may be reasonable but our findings should be confirmed by additional randomized data trials.

Basal ganglia hemorrhage in a case report following spinal surgery

BACKGROUND

Intracranial hemorrhage is a rare but potentially severe complication of spinal surgery. Most reported post-operative ICH cases consist of cerebellar hemorrhage. There are fewer reported cases of supratentorial ICH following spinal surgery.

CASE PRESENTATION

A 56-year-old woman underwent spinal surgery complicated by bilateral supratentorial intraparenchymal basal ganglia hemorrhage with both intraventricular extension and subarachnoid hemorrhage in both cerebral hemispheres.

CONCLUSION

The occurrence of neurological deterioration post-operatively following spinal surgery should alert physicians to the possibility of intracranial hemorrhage in order to facilitate rapid and optimal management. To our knowledge, this is the first case reporting basal ganglia hemorrhage following spinal surgery. Moreover, consideration should be given to the possibility of this complication prior to recommendation of elective spinal surgery.

A Systematic Literature Review of Patients With Carotid Web and Acute Ischemic Stroke

Background and Purpose—

Carotid web (CW) is a rare form of focal fibromuscular dysplasia defined as an abnormal shelf-like projection of intimal fibrous tissue into the carotid bulb. It is theorized that CW leads to ischemic stroke secondary to blood flow stasis and subsequent embolization. The natural history and optimal management of CW are unclear. To address this knowledge gap, we performed a systematic literature review (SLR) of CW.

Methods—

Our librarians performed a SLR for CW and related terminology. Patient-level demographics, stroke risk factors, neuroimaging findings, stroke recurrence or stroke free-duration, and treatment modality were extracted. We used descriptive statistics to characterize our results. When specific patient-level metrics were not reported, the denominators for reporting percentage calculations were adjusted accordingly.

Results—

Our literature search produced 1150 articles. Thirty-seven articles including 158 patients (median age 46 years [range 16–85], 68% women, 76% symptomatic) met entry criteria and were included in our SLR. Of the symptomatic CW patients: 57% did not have stroke risk factors, 56% who received medical therapy had recurrent stroke (median 12 months, range 0–97), and 72% were ultimately treated with carotid revascularization (50% carotid stenting, 50% carotid endarterectomy). There were no periprocedural complications or recurrent strokes in carotid revascularization patients.

Conclusions—

CW leads to ischemic stroke in younger patients without conventional stroke risk factors. We found a high stroke recurrence rate in medically managed symptomatic CW patients, whereas carotid revascularization effectively prevented recurrent stroke. Our findings should be interpreted with caution because of risk of publication and reporting bias.

Abstract WP69: Guideline-Based Intravenous rPA for Central Retinal Artery Occlusion: A Case Series and Systematic Review

Introduction: Central retinal artery occlusion (CRAO) rapidly leads to irreversible retinal damage with spontaneous visual recovery in only 10-20%. IV tPA may improve visual outcomes in CRAO, but protocols are heterogeneous. Deviation from acute ischemic stroke guidelines (AISG) for IV tPA is associated with symptomatic intracranial hemorrhage (sICH). Our study characterizes outcomes for CRAO patients treated with IV tPA per AISG to better define the risk and benefit.

Methods: We executed a systematic literature review (SLR) of IV tPA for CRAO in Cochrane, Embase, and Medline. Subsequently, we performed a retrospective chart review at two local academic hospitals. All CRAO patients identified locally or via SLR who were treated with IV tPA per AISG were included in our study. Primary outcomes included improvement in visual acuity (VA), defined as ≥0.3 logMAR, and safety, specifically sICH.

Results: Our SLR yielded 136 articles of which 19 were eligible. 137 total CRAO patients were identified, 32 (23%) of whom received IV tPA per AISG. 13 additional CRAO patients treated per AISG were identified locally (Table 1A). Of these 45 cases, VA was reported in 39, with improvement in 64%, no change in 28%, and worsening in 8%. The risk of sICH was 2.2% (n=1) (Table 1B). The case of sICH occurred locally, with hemorrhage adjacent to 2 chronic appearing infarcts. Post-sICH it was impossible to determine radiographically whether a component of his infarct may have been subacute. Interestingly, in our local cases, clinically silent diffusion restriction was evident on MRI in 6 patients (46%).

Conclusion: Our study suggests that IV tPA administered per AISG may improve visual outcomes in comparison to the natural history of CRAO, however, the rate of sICH was not inconsequential. Additionally, our case series includes the first reported sICH in a CRAO patient administered IV tPA per AISG. Randomized studies are warranted to assess the efficacy and safety of IV tPA administered per AISG in CRAO.

Abstract WP340: Primary Intracerebral Hemorrhage and Perihematomal Edema Volumes in Diabetics on Sulfonylureas: A Case-Control Study

Introduction: Sulfonylureas (SU) drugs have been linked to reduced cerebral edema, lower rate of hemorrhagic transformation, and improved functional outcome following ischemic stroke, but their effects in primary intracerebral hemorrhage (pICH) have not yet been explored. We investigated whether pre-existing SU use influenced intracerebral hemorrhage (ICH) volume, perihematomal edema (PHE) volume and hospital discharge disposition in type II diabetics (DMII) presenting with pICH.

Methods: We performed a retrospective chart review of all diabetic patients presenting with ICH to 2 tertiary academic centers between 2006 and 2016. All patients with DMII, pICH, admission computed tomography (CT) scan, and current SU use at the time of admission were included in our study. For each case, 2 matched controls (by admission date ± 5 years, age ± 5 years, hematoma location [deep vs. lobar], use of antiplatelet agent or anticoagulant) with DMII and pICH were consecutively selected for study inclusion. Intracerebral hemorrhage volumes and PHE volumes were measured via region-of-interest analysis on admission CT for each patient. To mitigate the influence of ICH volume on PHE, the PHE/ICH surface area ratio was calculated. Lastly, hospital discharge disposition was determined for each patient. We utilized the Wilcoxon rank sum test and Fischer’s exact test to assess differences between the 2 groups.

Findings: Of 317 patients screened, 21 SU cases and 42 non-SU matched controls met criteria for study inclusion. Patients on SUs had significantly lower admission ICH volumes (median 4mL, IQR 2-30 vs. median 25mL, IQR 6-60; p =0.011), PHE volumes (median 4mL, IQR 0.9-24 vs. median 17, IQR 6-37; p =0.0095), and PHE/ICH surface area ratios (median 0.28, IQR 0.1-0.4 vs. median 0.43, IQR 0.3-0.6; p =0.013) as compared to matched controls. Sulfonylurea use was also associated with improved discharge disposition ( p =0.0062).

Conclusions: In patients with type II diabetes and pICH, SU use predicted lower ICH and PHE volumes, lower PHE/ICH surface area ratios, and favorable discharge disposition. Further studies are warranted to better elucidate the potential benefits of SUs in pICH.

Abstract TP76: Symptomatic Intracranial Hemorrhage After IV tPA for Acute Ischemic Stroke in Patients with Relative Contraindications

Introduction: Contraindications to IV tPA in acute ischemic stroke (AIS) limits access to a proven medical therapy. A 2015 AHA review assigned Class 3 recommendations (harm) to IV tPA for AIS patients with prior intracranial hemorrhage (pICH), stroke within the last 3 months (SW3), or low platelets (LP) defined as platelets < 100,000. These recommendations, however, were based on sparse literature, notably only 4 AIS patients with pICH and 31 with LP, were reviewed. Our study further investigates the safety of IV tPA in these patient populations.

Methods: We retrospectively reviewed all AIS cases treated with IV tPA at 2 academic centers from 1998-2015 and 2013-2015. Clinical data, including patient demographics, NIHSS, and relative exclusion criteria, was abstracted from each institution’s prospectively maintained stroke database. Neuroimaging and medical chart review was performed by two stroke neurologists.

Results: 324 consecutive AIS patients treated with IV tPA were reviewed. We identified 12 patients who met current Class 3 exclusion criteria (eight pICH, two SW3, two LP). Two patients developed symptomatic hemorrhagic transformation and both had pICH (Table). For comparison, the symptomatic ICH rate in AIS patients receiving IV tPA without relative exclusion criteria was 2.37%, a statistically significant difference (p<0.02, using Fisher’s exact test).

Conclusions: 12 AIS patients with Class 3 exclusion criteria were treated with IV tPA. Our eight reported cases of IV tPA in pICH patients adds substantially to the existing literature. In this study, 25% of patients with pICH developed symptomatic ICH after IV tPA. Although the low number of eligible patients limits interpretation of our findings, continued caution when considering IV tPA for AIS patients with pICH may be warranted. More data is needed to clarify the impact these relative contraindications have on the treatment of AIS.

Abstract 207: A Systematic Literature Review of Patients with Carotid Web and Acute Ischemic Stroke

Introduction: Carotid Web (CW) is a rare form of focal fibromuscular dysplasia that results in an abnormal shelf-like projection of intimal fibrous tissue into the carotid bulb. It is theorized that CW leads to ischemic stroke secondary to blood flow stasis and subsequent embolization. There is uncertainty in diagnosis, prognosis, and optimal management of this uncommon entity. To address this knowledge gap, we performed a systematic literature review (SLR) of CW.

Methods: Our literature search for CW and related terms yielded 1017 results. After a preliminary assessment of all 1017 retrieved manuscripts; 72 manuscripts were reviewed in detail. A total of 31 manuscripts met entry criteria and were included in our SLR. We present the demographics, cardiovascular (CV) risk factors, neuroimaging findings, stroke recurrence or stroke free-duration, and treatment modality of CW patients.

Results: Our SLR resulted in 104 patients with CW, (median age at presentation: 45.7 [IQR 45-57], 52.3% female). The majority (68.3%) of CW patients did not have CV risk factors, however, 22.2% of patients were smokers. 47.8% of patients suffered recurrent stroke. The majority of patients were ultimately treated with antiplatelet therapy (94.4%) and 21.2% underwent carotid revascularization (4.8% carotid stenting, 16.3% carotid endarterectomy). None of the patients who underwent revascularization had a reported stroke recurrence. See Table.

Conclusions: CW is a rare disease leading to ischemic stroke in younger patients without typical CV risk factors. CW patients in our SLR were at extremely high risk for recurrent stroke (47.8%). Aggressive secondary stroke prevention measures are indicated in this patient population, however, the optimal treatment strategies remain unclear. Carotid revascularization may be the definitive treatment for certain patients with CW, but further studies are needed as incomplete reporting and potential publication bias limit our findings.

Abstract WMP89: Stroke Code De-escalation: Safety and Outcomes

Introduction: “Stroke codes” (SCs) facilitate the timely treatment of acute ischemic stroke (AIS) with IV tPA or intra-arterial thrombectomy (IAT), but are inherently resource-intensive and can expose patients to unnecessary and potentially harmful interventions. While all healthcare providers are encouraged to activate SCs, this might lead to low SC-to-treatment-ratios (SCTR). We examined the impact of de-escalation of stroke codes (DSCs) on SCTR.

Methods: DSCs were initiated in our institution in January 2015. All DSCs were reviewed for the patient’s eligibility for IV tPA or IAT, and reason for de-escalation. We reviewed all stroke codes 12 months before and after the initiation of this process and compared the SCTR by chi-squared testing.

Results: In 2014, prior to DSCs, 253 SCs resulted in 22 AIS interventions (22 IV tPA) for a SCTR of 8.7%. In 2015, 348 SCs were activated with 64 subsequent DSCs (18.4%) and 45 AIS interventions (38 IV tPA, 7 IAT, 7 both), for a SCTR of 15.8%. The improvement in SCTR after introducing DSCs was statistically significant (p=0.012). When restricting the analysis to IV tPA interventions alone, there remained a trend (p=0.068) towards improvement in SCTR. Retrospective chart review did not reveal any DSC cases that resulted in missed opportunity for IV TPA or IAT treatment. No DSCs were due to an acute ICH. Justifications for de-escalations are summarized in figure 1.

Conclusions: The introduction of DSCs resulted in a statistically significant absolute improvement in SCTR of 7.1%. Importantly, DSCs did not result in any eligible AIS patient forgoing IV tPA or IAT, nor missed ICH. More research is needed to increase the yield of stroke codes, refine the criteria for both activating and de-escalating them, and quantify the resource and cost implications of such de-escalations.

Abstract TP154: Infarct Volume and Prolonged Intubation are Critical Determinants of Inpatient Rehabilitation Cost in Anterior Circulation Large Vessel Occlusion Stroke Patients

Introduction: Anterior circulation large vessel occlusion (ACLVO) stroke is one of the most devastating stroke subtypes. Significant recent advances, including endovascular thrombectomy, have markedly improved ACLVO stroke outcomes. The economic burden of ACLVO stroke treatment is now an important consideration. Our study investigates the critical determinants of acute inpatient rehabilitation (AIR) cost in ACLVO stroke.

Methods: We utilized comprehensive patient-level cost-tracking software to calculate AIR costs for ACLVO stroke patients at our institution between July 2012-October 2014. Cost was calculated from the hospital perspective. Patient demographics, clinical course, neurologic exam, and imaging findings were analyzed. Variables with p-value <0.20 in univariate analysis were included in multivariable analysis to determine significant predictors of AIR cost (p<0.05).

Results: 65 patients were included in our analysis (median age 61 [IQR 54-73], median AIR admit NIHSS 12 [6-16]). Univariate analysis results are shown (Figure). In our multivariable analysis the only statistically significant predictors of AIR cost were the patient’s final infarct volume (p<0.001) and intubation >48 hours during the hospitalization (p=0.044). AIR costs increased by $66.46 for every 1 cubic centimeter increase in infarct volume.

Conclusion: Infarct volume and intubation >48 hours were significant predictors of AIR cost in ACLVO stroke patients at our institution. ACLVO stroke interventions that limit infarct volume may decrease AIR costs, in addition to avoidance of intubation and aggressive pursuit of extubation when feasible.

Abstract 132: Final Infarct Volume is a Critical Determinant of Hospitalization Cost in Anterior Circulation Large Vessel Occlusion Stroke

Background: Anterior circulation large vessel occlusion (ACLVO) stroke, one of the most devastating stroke subtypes, is associated with substantial economic burden. Identifying predictors of increased ACLVO stroke hospitalization cost is essential to developing cost-effective treatment strategies.

Methods: We utilized comprehensive patient-level cost-tracking software to calculate hospitalization costs for ACLVO stroke patients at our institution between July 2012-October 2014. Patient demographics and neuroimaging findings were analyzed. Predictors of hospitalization cost were determined using multivariable linear regression. In addition to our primary analysis (all eligible ACLVO patients), we conducted subgroup analyses by treatment (endovascular, IV tPA-only, and no reperfusion therapy) and sensitivity analyses.

Results: 341 patients (median age 69 [IQR 57-80], median NIHSS 16 [IQR 13-21], median hospitalization cost $16,446 [IQR $9823-$27,165]) were included in our primary analysis; final infarct volume (FIV), parenchymal hematoma, age, obstructive sleep apnea, and baseline NIHSS were significant predictors of hospitalization cost (Figure). FIV alone accounted for 20.51% of the total variance in hospitalization cost. Notably, FIV was consistently the most robust predictor of increased cost across primary, subgroup, and sensitivity analyses. Over the observed range of FIVs in our cohort, each additional 1cc of infarcted brain tissue increased hospitalization cost by $122.35.

Conclusion: FIV is a critical determinant of increased hospitalization cost in ACLVO stroke. Therapies resulting in reduced FIV may not only improve clinical outcomes, but prove cost-effective.

Streamlining door to recanalization processes in endovascular stroke therapy

Background

In acute stroke due to large vessel occlusion, faster reperfusion leads to better outcomes. We analyzed the effect of optimization steps aimed to reduce treatment delays at our center.

Methods

Consecutive patients with ischemic stroke treated with endovascular therapy were prospectively analyzed. We divided the patients into pre-optimization (20 April 2012 to 8 October 2013) and post-optimization (9 October 2013 to 29 July 2014) periods. The main interventions included: (1) continuous feedback; (2) standardized immediate emergency department attending to stroke attending communication with interventional team activation for all potential interventions; (3) pre-notification by the emergency medical service; (4) minimizing additional diagnostic testing; (5) direct transport to the CT scanner; (6) transport directly from the CT scanner to the angiography suite. The main metric used to measure improvement was door to groin puncture time (D2P).

Results

We included a total of 286 patients (178 pre-optimization, 108 post-optimization). There were no significant differences between major baseline characteristics between the groups with the exception of higher median CT Alberta Stroke Program Early CT Score in the pre-optimization group (p=0.01). Median D2P improved from 105 min pre-optimization to 67 min post-optimization (p=0.0002). Rates of good clinical outcomes (modified Rankin Scale 0–2 at 3 months) were similar in both groups, with a trend toward a better outcome in the post-optimization group in a subgroup analysis of patients with anterior circulation occlusion who received intravenous tissue plasminogen activator.

Conclusions

This pilot study demonstrates that D2P times can be significantly reduced with a standardized multidisciplinary approach. There was no significant difference in the rate of 3-month good outcome, which is most likely due to the small sample size and confounding baseline patient characteristics.

Relationship Between Lesion Topology and Clinical Outcome in Anterior Circulation Large Vessel Occlusions

BACKGROUND AND PURPOSE

Diffusion-weighted imaging (DWI) Alberta Stroke Program Early CT Score (ASPECTS), a surrogate of infarct volume, predicts outcome in anterior large vessel occlusion strokes. We aim to determine whether topological information captured by DWI ASPECTS contributes additional prognostic value.

METHODS

Adults with intracranial internal carotid artery, M1 or M2 middle carotid artery occlusions who underwent endovascular therapy were included. The primary outcome measure was poor clinical outcome (3-month modified Rankin Scale score, 3-6). Prognostic value of the 10 DWI ASPECTS regions in predicting poor outcome was determined by multivariable logistic regression, controlling for final infarct volume, age, and laterality.

RESULTS

Two hundred and thirteen patients (mean age, 66.1±14.5 years; median National Institutes of Health Stroke Scale, 15) were included. Inter-rater reliability was good for DWI ASPECTS (deep regions, κ=0.72; cortical regions, κ=0.63). All DWI ASPECTS regions with the exception of the putamen were significant predictors (P<0.05) of poor outcome in univariate analyses. Statistical collinearity among ASPECTS regions was not observed. Using penalized multivariable logistic regression, only M4 (odds ratio, 2.82; 95% confidence interval, 1.39-5.76) and M6 (odds ratio, 2.45; 95% confidence interval, 1.15-5.3) involvement were associated with poor outcome. M6 involvement independently predicted poor outcome in right hemispheric strokes (odds ratio, 5.8; 95% confidence interval, 1.9-20.3), whereas M4 (odds ratio, 4.3; 95% confidence interval, 1.3-15.0) involvement predicted poor outcome in left hemispheric strokes adjusting for infarct volume. Topologic information modestly improved the predictive ability of a prognostic score that incorporates age, infarct volume, and hemorrhagic transformation.

CONCLUSIONS

Involvement of the right parieto-occipital (M6) and left superior frontal (M4) regions affect clinical outcome in anterior large vessel occlusions over and above the effect of infarct volume and should be considered during prognostication.

Abstract W P38: Collateral Circulation Status Correlates With Aspects Decay During Inter-facility Transfer After Anterior Acute Ischemic Stroke Patients

Introduction: The collateral circulation plays an important role in the dynamic process of cerebral ischemia. The aim of this study is to determine if collateral status correlates with the early ischemic changes measured by the rate of Alberta Stroke Program Early CT Scores (ASPECTS) decay in emergently transferred acute ischemic stroke patients with anterior large vessel conclusions.

Material and methods: We retrospectively analyzed the data of patients referred to our comprehensive stroke center from 7 outside hospitals between January 15, 2006 and January 15, 2014. Collateral status was assessed using an initial CT angiography obtained before treatment, and graded as "Good" (the entire medial cerebral artery reconstitutes with contrast) or "Poor" (partial or no reconstitution of the distal medial cerebral artery), by two independent reviewers (CA and WD).

ASPECTS decay was calculated in the following ways: 1. Absolute ASPECTS decay: (A1-A2)/T, 2. Relative ASPECTS decay: [(A1-A2)/A1]/T 3. Net ASPECTS difference: (A1-A2) and 4. Relative ASPECTS difference: (A1-A2)/A1; where A1= ASPECTS 1st CT, A2= ASPECTS 2nd CT, T= hours between 2 CT scans.

Results: After reviewing 701 medical records from transferred patients, 51 patients with mean age 65±3 yrs and median initial NIHSS of 17 (IQR 14-21) were selected. In the multivariate analysis, good collateral status was independently associated with lower rates of ASPECTS decay measured by the relative rate of ASPECTS decay (0.04+/-0.01 score/h; p<0.05), the net ASPECTS difference (1.10+/-0.17 score/h, p<0.05) and the relative ASPECTS difference (0.12+/-0.02 score, p<0.05). The relative ASPECTS difference was most strongly associated with collateral status, and an independent predictor of good outcome (p=0.047) and final infarct volume (p=0.001) after controlling for age and NIHSS in a multivariate analysis.

Conclusions: Good collateral circulation status is associated with lower rates of ASPECTS decay in transferred patients, which also tend to have smaller final infarct volumes and better clinical outcome after 3 months. The analysis of the collateral circulation gives us a better understanding of the pathophysiology in acute ischemic stroke.

Abstract W P39: Relationship Between Lesion Topology and Clinical Outcome In Anterior Circulation Large Vessel Occlusions

Background: Final infarct volume is a robust predictor of outcome in large vessel occlusion (LVO) patients but lesion location may also impact outcomes in these patients. DWI ASPECTS on follow-up MRI imaging, like infarct volume, is predictive of outcome in addition to providing information regarding lesion location. We aim to determine whether individual DWI ASPECTS regions have an impact on clinical outcome in anterior circulation large vessel occlusions.

Methods: Patients with intracranial ICA, M1 and M2 MCA occlusions who underwent endovascular therapy between 2007 and 2014 at UPMC were included. Baseline demographics and outcomes including final infarct volume and 3-month mRS were collected. DWI ASPECTS based on follow-up MRI (12-72 hrs) was assessed by two observers. The impact of each DWI ASPECTS region on predicting poor outcome (mRS 3-6) was assessed by logistic regression analysis.

Results: 213 patients were included in the analysis (mean age 66.1±1.0 yrs, median NIHSS 15 [IQR 11-18], 19.5% ICA and 72% M1 MCA occlusions, 3-month mRS 3-6 of 46.8%). Inter-rater reliability was good for DWI ASPECTS (Deep ASPECTS regions: Kappa=0.72, Cortical ASPECTS regions: Kappa=0.63). All DWI ASPECTS regions with the exception of “putamen” were significant predictors (p<0.05) of poor outcome in univariate analysis. In a multivariate analysis with all 10 ASPECTS regions included, only M4 (OR=0.33 95%CI 0.16-0.70, p=0.003) and M6 (OR 0.39, 95%CI 0.18-0.85, p=0.018) significantly predicted poor outcome while deep regions (caudate, putamen and internal capsule) did not. After controlling for final infarct volume, M4 (p=0.045) and M6 (p=0.018) regions remained significant predictors of poor outcome. M6 was independently associated with poor outcome in right hemispheric lesions (OR 0.13 95%CI 0.04-0.47, p=0.002) while M4 (OR 0.14 95%CI 0.04-0.48, p=0.011) predicted poor outcome in left hemispheric lesions.

Conclusions: Involvement of the right parieto-occipital (M6) and left superior-frontal (M4) regions seem to have a significant impact on outcome in LVO patients. While these results need to be replicated in other patient cohorts, lesion topology may also need to be considered in outcome prediction in LVO patients.

Abstract T MP1: The Pittsburgh Collateral Ratio: A Novel Method to Assess Collateral Circulation Status in Acute Mca Occlusions

Introduction: Collateral status is a robust predictor of recanalization and clinical outcome in acute ischemic stroke and numerous collateral grades exist to evaluate it (many of which are qualitative or semi-quantitative) being CT angiography (CTA)-based collateral grading the most frequently used. We attempt to quantitatively assess collateral grade based on a comparison between contrast filling proximal and distal to a medial cerebral artery (MCA) occlusion.

Material and methods: We retrospectively reviewed the data of patients with M1 MCA occlusions referred to our center between January 15, 2006 and January 15, 2014. The Pittsburgh Collateral Ratio (PCR) was determined by calculating the mean Hounsfield Units (HU) in regions of interest (ROI) in the MCA, both pre and post-thrombus at the time of maximal opacification of the vessel (PCR = HU post-thrombus/ HU pre-thrombus). Ipsilateral (iPCR) and contralateral (cPCR) ratios were calculated. Two independent reviewers (CA and WD) graded pre-treatment CTA collateral status as good (the entire MCA reconstitutes with contrast) and poor (partial or no reconstitution of the distal MCA). PCR was compared to CTA collateral status and associated with good outcome (mRS 0-2 at 3 months) by logistic regression analysis.

Results: Fifty one patients were included (mean age 65±3 yrs, median initial NIHSS 17 [IQR 14-21]). Strong correlation between PCR and CTA collateral grade was observed (iPCR: Pearson’s R=-0.796, p<0.001, cPCR: Pearson’s R=-0.64, p<0.001). iPCR was highly predictive of good collateral status (AUC 0.89, p<0.001) and iPCR ≥ 0.6 had a 100% sensitivity and 64% specificity for good collateral status. In multivariate analysis after controlling for age, NIHSS and ivTPA, iPCR was an independent predictor of good outcome (p=0.02).

Conclusions: The PCR is a simple and accurate method to evaluate collateral circulation status in MCA occlusion patients and further validation of this score in larger cohorts is warranted.

Abstract 144: The Pittsburgh Outcomes After Stroke Thrombectomy (POST) Score Predicts Good Outcomes After Endovascular Therapy for Anterior Circulation Large Vessel Occlusions

Background: Independent predictors of good outcome following large vessel occlusions (LVO) include age, infarct volume, NIHSS at presentation and revascularization status. The aim of this study was to develop an easy-to-use tool to predict good outcome following endovascular treatment for LVO.

Methods: In a derivation cohort of patients with anterior circulation LVO treated with endovascular therapy at Grady Memorial Hospital (GMH, n=247), we performed logistic regression to identify independent predictors of good outcome (mRS 0-2 at 90 days). Factors were weighted based on B-coefficients to generate a score (POST) that predicts good outcome. The derivation cohort was divided in risk group quartiles and correlation analysis between predicted and observed rates of good outcomes was performed. POST was also validated in two cohorts derived from the University of Pittsburgh Medical Center (UPMC, n=380) and the DEFUSE 2 database (n=105).

Results: In the derivation cohort (mean age 66±1 yrs, median NIHSS 18), independent predictors (p<0.2) of good outcome included final infarct volume (FIV; OR 0.97, 0.96-0.98), age (OR 0.96, 0.94-0.98), NIHSS at presentation (OR 0.93, 0.88-0.98) and PH1/PH2 hemorrhage (H; OR 0.3, 0.06-1.6, p=0.15). POST was defined as Age + 0.5 X FIV + 15 X H. Patients in the lowest POST quartile (<60) had a 91% chance of good outcome as compared to 3% in the highest POST quartile (≥120). There was a strong correlation between predicted and observed rates of good outcomes in the 4 groups (R=0.99, p<.001). POST performed well in predicting good outcomes in the derivation (AUC=0.85), as well as the UPMC (AUC=0.81) and DEFUSE 2 (AUC=0.86) validation cohorts.

Discussion: The POST score is a validated tool to predict good clinical outcomes following endovascular therapy in patients with acute large vessel occlusions. This tool can guide families and physicians in clinical decision making following endovascular therapy.

Abstract W P10: Endovascular Treatment for Anterior Circulation Stroke Leads to Similar Outcomes in Very Early (within 3 hours) versus Selected Late (Beyond 8 Hours) Presenting Patients

Background and Purpose: Endovascular therapy for acute ischemic stroke (AIS) is thought to have a higher chance of good outcome in patients presenting early than in those presenting late. However, a subgroup of late presenting patients, identifiable through advanced neuroimaging methods, has favorable physiology and can still experience good outcomes following reperfusion. We sought to compare outcomes in patients treated very early (within 3 hours) vs. late (beyond 8 hours) at our institution.

Methods: Via retrospective analysis of a prospectively collected database of 961 consecutive patients treated at our center (2001-2013), we identified patients with anterior circulation stroke who underwent endovascular treatment < 3 hours from time last seen well (with or without prior IV thrombolysis), and patients who underwent endovascular treatment > 8 hours from time last seen well, selected with advanced neuroimaging. Baseline characteristics and outcomes including MRI derived final infarct volumes (FIV) for each group were analyzed. [Table]

Results: We identified 108 patients treated < 3 hours and 177 patients treated > 8 hours from time last seen well. Baseline characteristics were not significantly different between the two groups except for differences in atrial fibrillation, baseline ASPECTS, and baseline NIHSS. All outcome measures were not significantly different between the two treatment groups. [Table]

Conclusion: Despite larger baseline infarcts in the > 8 hour group compared to the < 3 hour group, rates of good outcomes, FIV, and mortality did not differ between the two groups. These findings may be explained by differences in the rate of infarct growth from presentation to reperfusion in the two patient populations.

Abstract T MP7: TICI 2B vs. TICI 3: Differences in Infarct Volumes and Clinical Outcomes in Proximal Intracranial Large Vessel Occlusions Treated With Endovascular Therapy

Introduction: Successful recanalization independently predicts good outcome following endovascular therapy for acute large vessel occlusions. Thrombolysis In Cerebral Infarction (TICI) status 2B (near-complete revascularization) and 3 (complete revascularization) are routinely combined to reflect successful recanalization. Whether outcomes in these two groups are truly comparable, has not been demonstrated.

Methods: In a retrospective analysis of a prospectively collected patient cohort at our center (2008-2013), we identified adults with intracranial internal carotid and middle cerebral artery M1 occlusions who underwent endovascular therapy within 8 hours from symptom onset, achieved operator-measured TICI2B or TICI3 status and had a documented 90 day modified Rankin Score (mRS). Baseline characteristics (age, NIHSS score, time to groin puncture, ASPECTS, risk factors), final infarct volume, rate of good outcome (mRS 0-2), intracranial hemorrhage and mortality were assessed.

Results: 99 patients (TICI2B:N=64, TICI 3:N=35, Median NIHSS 16, median ASPECTS 9) were included. No differences in baseline characteristics were identified (Figure A). Patients with TICI3 status had smaller final infarct volume (6.2cc vs. 22.5cc, p=0.007, Figure B), higher rate of good outcome (74.3% vs 45.3%, p=0.006), lower mortality (5.7% vs. 28.1%, p=0.008, Figure C) and similar hemorrhage rates (p=0.2) as compared to TICI2B. After controlling for age, NIHSS and ASPECTS, TICI3 status independently predicted good outcomes (OR 4.74 95%CI 1.53-14.67, p=0.007).

Conclusions: Patients with TICI3 recanalization have smaller infarct volumes and better clinical outcomes as compared to TICI2B. With the improving efficiency of mechanical thrombectomy, future thrombectomy stroke trials should report TICI2B and TICI3 status separately.

Abstract T MP10: Pittsburgh Response to Endovascular Therapy (PRE) Score Predicts Likelihood of Benefit From Endovascular Therapy in Anterior Circulation Large Vessel Occlusions

Background: Endovascular therapy seems to benefit a subset of patients with acute large vessel occlusions (LVO). The aim of this study was to develop a clinically useful tool to identify patients with anterior circulation large vessel occlusions who are likely to benefit from endovascular therapy.

Methods: Adults with anterior circulation LVOs were included. In the derivation cohort (2008-2012) from Grady Memorial hospital (GMH), independent predictors (p<0.2) of good outcome (mRS 0-2 at 90 days) were determined using logistic regression. Highly weighted factors were used to derive the PRE score as a predictor of good outcome. Four risk-quartiles were created based on observed rates of good outcomes. The PRE score was validated in the UPMC database (n=322, 2007-2013) and in a database from Unitat d'Ictus Vall d'Hebron (UIVH), Barcelona (n=203, 2009-2012). Performance of PRE was compared with HIAT-2, THRIVE and ASPECTS in predicting good outcome.

Results: In the derivation cohort (N=247, mean age 66±1, median NIHSS 18), independent predictors of good outcome included age (OR 0.96, 0.94-0.98), NIHSS (OR 0.92, 0.87-0.98) and ASPECTS (OR 1.96, 1.6-2.5). The PRE score was calculated as follows: PRE Score = Age + 2 x NIHSS - 10 x ASPECTS. PRE predicted good outcomes in the derivation cohort (AUC 0.79) as well as in the validation cohorts (UPMC: AUC 0.79 and UIVH: AUC 0.72) and comparative rates of good outcome were observed in the four PRE quartiles. PRE < 25 was associated with good outcome (OR 6.0, 3.5-10.5), and controlling for TICI 2B/3 reperfusion status further strengthened this association (OR 12.8, 4.5-36.2). PRE (AUC 0.79) performed better than HIAT2 (AUC 0.75), THRIVE (AUC 0.73) and ASPECTS (AUC 0.57) in predicting good outcomes after endovascular therapy.

Conclusions: The PRE score is a validated tool to predict benefit from endovascular therapy in patients with anterior circulation LVO. PRE can aid in the selection of patients for endovascular reperfusion therapy.

Abstract W P23: Predictors of Time From Groin Puncture to Base Catheter Placement

Background and Purpose: Time to reperfusion is recognized as an important predictor of good outcome in endovascular stroke therapy. A significant but unstudied factor in delay to reperfusion is prolonged time from groin puncture to base catheter placement (P2C). The purpose of this study was to assess the factors that influence time from P2C in the cohort of patients in whom procedural steps were collected prospectively.

Methods: A prospective analysis of patients who had intra-arterial therapy for acute stroke from August of 2012 to August of 2013 was performed. Following characteristics were collected: baseline clinical demographics, aortic arch types, time from P2C, procedural and clinical outcomes.

Results: Data from a total of 143 patients were collected prospectively {median age 69 years; median baseline NIH Stroke Scale 16; occlusion sites: MCA-M1 71%; MCA-M2 13%, ICA-T 6%, basilar artery 10%, tandem occlusion 26%}. Patients were further divided based on their arch type (type 1: 48%, type 2: 33%, type 3: 13%). Majority of the patients were treated with newer mechanical embolectomy devices (manual aspiration +/- stent-retriever 96%). Recanalization rate (TICI 2b or 3) was 90%. The median procedural times were as follow (minutes): time from P2C: 20, time from baseline catheter to reperfusion: 36, median total procedural times: 85. The rate of favorable functional outcomes at 90 days (mRS 0-2) was 45%. Patients with favorable outcomes had shorter P2C (31 min vs. 19 min p=0.02). In a multivariate analysis the predictors of longer P2C were age (OR 1.04, P=0.05, 95% CI 1.00-1.08), vertebrobasilar location (OR 5.4, P=0.027, 95% CI 1.21-24.1), smoking (OR 3.7, P=0.02, 95% 1.2-11.1), and with trend toward significance for hypertension (OR 3.03, P=0.062, 95% 0.94-0.97).

Discussion: Shorter P2C is associated with higher rate of favorable outcomes. Independent risk factors associated longer time are age, vertebrobasilar occlusions, active smoking and history of hypertension. Alternative arterial access may be considered in patients who are likely to have longer P2C.