Association of Neighborhood-Level Socioeconomic Factors With Delay to Hospital Arrival in Patients With Acute Stroke

BACKGROUND AND OBJECTIVES

Delivery of acute ischemic stroke (AIS) therapies is contingent on the duration from last known well (LKW) to emergency department arrival time (EDAT). One reason for treatment ineligibility is delay in presentation to the hospital. We evaluate patient and neighborhood characteristics associated with time from LKW to EDAT.

METHODS

This was a retrospective observational study of patients presenting to the Yale New Haven Hospital in the AIS code pathway from 2010 to 2020. Patients presenting within 4.5 hours from LKW who were recorded in the institutional Get With the Guidelines Stroke registry were classified as early while those presenting beyond 4.5 hours were designated as late. Temporal trends in late presentation were explored by univariate logistic regression. Using variables significant in univariate analysis at p < 0.05, we developed a mixed-effect logistic regression model to estimate the probability of late presentation as a function of patient-level and neighborhood (ZIP)-level characteristics (area deprivation index [ADI] derived from the Health Resources and Services Administration), adjusted for calendar year and geographic distance from the centroid of the ZIP code to the hospital.

RESULTS

A total of 2,643 patients with AIS from 2010 to 2020 were included (63.4% presented late and 36.6% presented early). The frequency of late presentation increased significantly from 68% in 2010 to 71% in 2020 (p = 0.002) and only among non-White patients. Patients presenting late were more likely to be non-White (37.1% vs 26.9%, p < 0.0001), arrive by means other than emergency medical services (EMS) (32.7% vs 16.1%, p < 0.0001), have an NIHSS <6 (68.7% vs 55.2%, p < 0.0001), and present from a neighborhood with a higher ADI category (p = 0.0001) that was nearer to the hospital (median 5.8 vs 7.7 miles, p = 0.0032). In the mixed model, the ADI by units of 10 (odds ratio [OR] 1.022, 95% confidence interval [CI] 1.020-1.024), non-White race (OR 1.083, 95% CI 1.039-1.127), arrival by means other than EMS (OR 1.193, 95% CI 1.145-1.124), and an NIHSS <6 (OR 1.085, 95% CI 1.041-1.129) were associated with late presentation.

DISCUSSION

In addition to patient-level factors, socioeconomic deprivation of neighborhood of residence contributes to delays in hospital presentation for AIS. These findings may provide opportunities for targeted interventions to improve presentation times in at-risk communities.

Abstract 9: Autoregulation-based Blood Pressure Targets After Endovascular Thrombectomy

Background: Optimal level blood pressure (BP) targets in acute stroke remain elusive. Tailored hemodynamic management after endovascular thrombectomy (EVT) may reduce the risk of reperfusion injury and promote penumbral recovery. Our study aimed to evaluate the relationship between personalized autoregulation-based BP targets, secondary brain injury, and functional outcomes.

Methods: We prospectively enrolled 200 patients with acute ischemic stroke who underwent EVT. Autoregulatory function was continuously measured for >=24 hours using simultaneous recordings of near-infrared spectroscopy and mean arterial pressure (MAP). The resulting autoregulatory index was used to calculate and trend the BP range at which autoregulation was most preserved. Percent time and “dose” that MAP exceeded the upper limit or dropped below the lower limit of autoregulation (ULA, LLA) were calculated for each patient. Hemodynamic parameters were correlated with short-term clinical endpoints (symptomatic ICH), biomarkers of secondary brain injury (net water uptake, hemorrhagic transformation (HT), infarct progression), and 90-day functional outcomes.

Results: Personalized BP targets were successfully computed in 195 patients (mean age 70 ± 16, 45% female, mean NIHSS 14, mean monitoring time 31 ± 28 hours). Time above the ULA was associated with worse functional outcomes at 90-days after adjusting for age, sex, NIHSS, ASPECTS and TICI (adjusted OR per 10% increase 1.4, 95% CI 1.1-1.6, P=0.004). The burden of hyperperfusion was significantly greater among patients with HT (median 2.7 vs. 3.2 mmHg*min, p=0.01) and sICH (median 2.8 vs. 4.8 mmHg*min, p=0.05) than in those without it. Furthermore, time spent above the ULA was significantly correlated with net water uptake at 72 hours (r=0.37, p=0.03). Among patients with unsuccessful reperfusion, there was a non-significant correlation between time below the LLA and infarct progression (r=0.35, p=0.064).

Conclusions: In the largest study conducted to date, deviations from personalized BP targets were associated with an increased risk of secondary brain injury and worse functional outcomes. Autoregulation-oriented BP management represents a promising strategy for maximizing recovery after ischemic stroke.

Abstract WP154: Low-field Portable Mri For Routine Post-thrombectomy Assessment Of Ongoing Brain Injury

Introduction: Conventional MRI (cMRI) is not routinely available post-mechanical thrombectomy (MT), which can preclude accurate infarction assessment. Our objective was to evaluate the use of low-field portable MRI (pMRI) for bedside evaluation post-MT, including its use as a post-procedural baseline monitor.

Methods: Low-field pMRI was used to obtain bedside imaging in post-MT patients between December 2021 to August 2022 at Yale-New Haven Hospital. All pMRI exams were conducted in the standard ferromagnetic environment of the IR suite. Volumetric analyses were performed by a neuroradiologist using 3D Slicer software. If cMRI was not available for comparison, a CT was used. Patients’ charts were reviewed for pre-revascularization MAP and occurrences of MAP dropping by 10% and 20% from individual baselines between the time of pMRI and delayed imaging.

Results: A total of 25 patients (64% females, median age 77 years-old [IQR 69.5-84.5]) underwent bedside pMRIs in the IR suite post-MT. The median time from last known normal to access was 6 hours [IQR 4-17]. The median pMRI examination time was 30 minutes [IQR 17-32]. Of the 24 patients with available delayed imaging, 7 (29.2%) had infarct progression compared to immediate post-MT pMRI, while 15 patients (62.5%) had stable/decreased stroke volume. Two patients (8.3%) had parenchymal hemorrhage type 2 and were excluded from further analysis. There was no statistically significant difference between the proportions of favorable TICI scores (85.7% in the infarct progression group vs. 92.3% in the stable/decreased infarct group, p=1.00). Patients with infarct progression had comparable pre-revascularization MAP compared to those with stable/decreased delayed infarct volume (mean of 100.3±4.6 vs. 101.9±15.9 respectively, p=0.727) but had more occurrences of MAP dropping by 10% and 20% of their baseline between the time of pMRI and delayed imaging (mean of 35.0±23.3 vs. 14.7±11.3 occurrences, p=0.011; and mean of 21.7±16.5 vs. 8.5±9.5 occurrences, p=0.026, respectively).

Conclusions: The use of low-field MRI in the post-MT setting can facilitate benchmark brain monitoring and serial examinations to evaluate the impact of potential physiological perturbations that may impact ongoing brain injury.

Abstract 91: Large Vessel Occlusion Stroke Patients With Rapid Early Infarct Progression And Poor Collaterals Are Vulnerable To Blood Pressure Reductions

Introduction: The precise interactions between collateral perfusion, hemodynamics, and infarct growth after large vessel occlusion (LVO) require further definition. This study examined whether patients with poor collateral circulation and rapid early infarct progression are more vulnerable to reductions in blood pressure (BP).

Methods: We prospectively enrolled patients with LVO stroke who underwent thrombectomy. Volumes of arterial tissue delay and relative cerebral blood flow (CBF) were estimated with RAPID software; a poor collateral profile was defined by a hypoperfusion intensity ratio >0.4. Early infarct growth rate (EIGR) was defined as ischemic core volume (CBF<30%) divided by the time from symptom onset to imaging. A fast progressor profile was assigned to patients whose EIGR was >10 mL/h. The final infarct growth rate (FIGR) was the quotient of final infarct volume (FIV) and time from symptom onset to reperfusion. BP reduction was measured as the difference between admission mean arterial pressure (MAP) and lowest MAP before reperfusion.

Results: Fifty-five patients (mean age 69 + 15, mean NIHSS 13) with successful reperfusion (TICI 2B/3) were included in the analysis. The median MAP reduction was 17 (IQR 9, 32). Poor collateral perfusion and EIGR were independent predictors of FIV after adjusting for age and admission NIHSS (mean FIV 70 vs. 31 mL, p=0.012 and 60 vs. 29 mL, p=0.01, respectively). A significant interaction was found between MAP reduction and both collateral status (p=0.04) and progressor profile (p=0.01). For every 10 mmHg MAP reduction, patients with poor collaterals experienced an average increase in FIGR of 3.6 mL/h (Fig. 1A). Above a critical MAP reduction threshold of 30 mmHg, mean FIV was significantly larger in patients with rapidly progressing infarcts (p<0.01, Fig. 1B).

Conclusions: Patients with poor collaterals and rapid early infarct growth are at higher risk of accelerated infarct growth and larger FIV related to BP reductions.

Abstract WMP59: Trends And Predictors Of Delay In Hospital Presentation After Symptom Onset Among Ischemic Stroke Patients: A Single-center Study

Background: Delivery of acute ischemic stroke therapies is contingent on the duration from last known normal (LKN) to emergency department arrival time (EDAT).

Methods: We studied patients presenting to Yale-New Haven Hospital from 2010-2020 who met these criteria 1) ischemic stroke, 2) age ≥ 18, 3) not transferred from another hospital, and 4) stroke symptom onset prior to hospital presentation. The outcome was LKN to EDAT dichotomized at 4.5 hours. Temporal trends were assessed by linear regression. Covariates analyzed for association with later arrival were: age, gender, race, ethnicity, median household income < $50,000 by ZIP, arrival means, and NIHSS. We built a multivariable logistic regression model by stepwise selection with variables significant at p-value < 0.05).

Results: We included 5,242 ischemic stroke patients; 1,964 (37.5%) presented early (<4.5 hrs). Patients presenting early decreased from 47.2% to 32.3% over time (p<0.01, Figure 1 ) and downward slope was steeper among non-White patients. Compared to early presenters, late presenters were more likely younger (median 72 vs 74 years; p<0.001), of non-White race (35.3% vs 26.8%, p<0.001), of Hispanic ethnicity (8.2% vs 6.2%, p=0.010), have a median household income < $50,000 (27.0% vs 21.2%, p=<0.001), arrive by means other than emergency medical services (EMS) (66.4% vs 85.8%, p<0.001), and have an NIHSS < 4 (57.5% vs 41.6%, p<0.001). In a multivariable model, non-White race (OR 1.4, 95% C.I. 1.2-1.7), arrival by means other than EMS (OR 2.4, 95% C.I. 1.9-3.0), and NIHSS < 4 (OR 1.6, 95% C.I. 1.3-1.9) were significant, independent predictors of presenting later.

Conclusion: Frequency of ischemic stroke patients presenting beyond 4.5 hrs increased from 2010 to 2020. Non-White race, arriving by means other than EMS, and minor stroke symptoms were linked with delay in presentation. Further study is necessary to identify and target barriers to timely hospital presentation among ischemic stroke patients.

Abstract WP111: Deployment Of Portable, Bedside, Low-field Magnetic Resonance Imaging In The Emergency Department To Evaluate Patients With Acute Stroke

Background and Aims: MRI is critical for diagnosing acute stroke and guiding candidate selection for potential reperfusion therapy. However, rapid stroke evaluation using MRI is often dissuaded by the time required for patients to travel to access-controlled, high-field (1.5-3T) systems. Advances in low-field MRI enable the acquisition of clinically valuable images at the bedside. We report neuroimaging in patients presenting to the Emergency Department (ED) with stroke symptoms using a low-field portable MRI (pMRI) device.

Methods: A 64mT pMRI device was deployed in the Yale-New Haven Hospital ED from August 2020 to July 2021. Patients presenting as a “Stroke Code” or “Intracranial Hemorrhage Alert” with no MRI contraindications were scanned. Exams were performed at the bedside, in the vicinity of ED room equipment. Research staff acquired imaging via tablet, with images available immediately after acquisition. Sequences obtained and axial scan times (in minutes) included T1-weighted imaging (4:54), T2-weighted imaging (7:03), fluid-attenuated inversion recovery imaging (9:31), and diffusion-weighed imaging with apparent diffusion coefficient mapping (9:04). Patients’ demographic information, hours from the time of patients' last known normal (LKN) to time of scan, and discharge diagnoses (determined from final imaging interpretation) were assessed.

Results: pMRI exams were obtained on 54 patients (28 females, 51.9%; median age 71 years, 20-98 years). Discharge diagnoses included ischemic stroke (42.6%) no intracranial abnormality (31.5%), intraparenchymal hemorrhage (7.4%), atherosclerosis (7.4%), tumor (5.6%), subdural hematoma (3.7%), and intraventricular hemorrhage (1.9%). Patient LKN times ranged from 2 to 144 hours (median of 12 hours; 3 patients with no LKN excluded). The pMRI did not interfere with ED equipment and no significant adverse events occurred.

Conclusion: We report the use of a pMRI for bedside neuroimaging in the ED. This approach suggests that pMRI may be viable for supporting rapid diagnosis and treatment candidate selection in patients presenting with stroke symptoms to the ED.

Abstract WP76: Patients Express Satisfaction With Acute Video Telestroke Consultations

Introduction: Video telestroke consultations are increasingly utilized to provide acute stroke care virtually, yet it remains uncertain whether patients are satisfied with this medium of care. We aimed to evaluate patient perception of their care during video telestroke consultations in a HUB and SPOKE telestroke network.

Methods: Patients from Yale New Haven Health System and affiliate hospitals evaluated by video telestroke were screened for enrollment and contacted between 7-14 days from telestroke encounter to administer a telephone survey. Patients were excluded if the suspicion for cerebrovascular event was low, if primary language was not English, if in hospice, and if patient had confusion, cognitive impairment or aphasia during telestroke encounter or survey. The survey asked patients to rate the quality of the telestroke encounter and their satisfaction with various aspects of clinical care (Figure). Patient responses were evaluated using Chi-square analysis with SPSS v23.

Results: A total of 325 video telestroke consultations occurred between May 8, 2021 and August 5, 2021. Eighty-nine patients met criteria to be contacted for a follow up survey. Of those, thirty-one patients responded to the survey (15 female, mean age of 58.9 years old) and 80.6% of patients did not have any prior telemedicine experiences. Only 6.7% of patients perceived shortcomings in the ability of the emergency staff to use videoconference equipment and 13.3% observed difficulties with audio quality. Difficulties with equipment and audio quality were not associated with patient’s ability to understand their diagnosis (p=0.787 and p=0.782) and treatment recommendations (p=0.558 and p=0.684). All patients expressed good or very good satisfaction with video telestroke use and perceived that the video consultation was as good as a bedside visit.

Conclusions: Despite encountering some technical difficulties, patients expressed satisfaction with video telestroke encounters.

Abstract TMP55: Post-stroke Blood Pressure Variability In The Acute Phase Is Associated With Pre-stroke Blood Pressure Variability In Patients Undergoing Mechanical Thrombectomy

Introduction: High blood pressure variability (BPV) after endovascular thrombectomy is associated with post-stroke complications and poor neurological outcomes. However, whether BPV is an epiphenomenon of the stroke itself or causally related to the outcome remains unknown.

Objective: In this study we aimed to evaluate if a relationship exists between pre-and post-stroke BPV in patients with large vessel occlusions (LVO).

Methods: From our prospective stroke registry, we identified patients who had an anterior circulation LVO, underwent EVT, and had at least three blood pressure measurements recorded in the electronic medical record in the six months prior to their stroke admission. All patients had repeated time-stamped blood pressure data recorded for the first 72 hours after thrombectomy. Using the standard deviation of systolic BP, we calculated BPV for each patient and separated patients into tertiles based on their post-EVT BPV. The relationship between pre-stroke BPV and post-EVT BPV was analyzed using an ordinal logistic regression and Spearman’s rank correlation analysis.

Results: Two hundred fifty-two patients were included in our analysis (mean age 70±16.2 years, mean admission NIHSS 15±7, median pre-stroke BP measurements 14.5 (IQR 5.0-55.8)). Pre-stroke BPV gradually increased for patients with higher post-EVT BPV tertiles (tertile 1 = 13.2(±5.2) mmHg, tertile 2 = 15.0(±5.5) mmHg, tertile 3 = 16.7(±7.0) mmHg, p=0.001). A positive correlation was observed between pre-stroke BPV and post-EVT BPV (p<0.001, R=0.21). After adjusting for age and admission NIHSS, pre-stroke BPV was significantly associated with post-EVT BPV tertile membership (OR 1.37, 95% CI 1.02-1.86, p=0.039).

Conclusion: High pre-stroke BPV is correlated with high post-EVT BPV. Although larger, prospective studies are needed to provide definitive evidence of this relationship, our work suggests that high post-EVT BPV may be related to an underlying biological phenomenon and not merely a consequence of the stroke itself. Individuals with high BPV may benefit from more intensive blood pressure management in the acute phase after EVT.

Abstract P136: Feasibility and Safety of an Expedited Emergency Department TIA Evaluation

Introduction: Transient ischemic attack (TIA) can portend impending stroke, but it is unclear whether a TIA evaluation necessitates inpatient admission. We assessed feasibility and safety of a TIA protocol in the emergency room for low-risk TIA patients.

Methods: We studied low-risk TIA patients (ABCD2 score < 4, no significant vessel stenosis) before (January 2018-July 2019) and after (August 2019-March 2020) the implementation of an expedited, emergency room TIA protocol at a comprehensive stroke center. The pre-intervention cohort consisted of TIA patients in the institutional Get-With-The-Guidelines database who met pre-specified criteria ( Figure ) and were admitted. The post-intervention patients met the same criteria and underwent an expedited MRI with selected sequences. If the MRI showed no ischemia, patients were scheduled with rapid, outpatient stroke clinic follow-up and outpatient echocardiogram as indicated. We compared differences in outcomes of interest between the pre-and post-intervention cohorts including length of stay, radiographic and echocardiogram findings, and recurrent neurovascular events within 30 days.

Results: In total, 120 TIA patients met criteria (71 pre-intervention, 49 patient post-intervention). Demographic and clinical characteristics were similar except the pre-intervention pathway had a higher proportion of patients with a smoking history and presenting symptom of aphasia and dysarthria. Median time from MRI order to completion was 2.3 hours in the post-intervention cohort. Median length of stay was 7.7 hours (IQR 5.2-9.7) in the post-intervention cohort compared to 28.8 hours (IQR 24.4-42.4) pre-intervention. There were no differences in neuroimaging or echocardiographic findings and 30-day re-presentation for stroke, TIA, or mortality.

Conclusions: Our study demonstrates the feasibility and suggests safety of an expedited TIA protocol. Further study is needed to determine its generalizability.

Abstract MP35: Blood Pressure Reductions Before Arrival at a Thrombectomy-Capable Hospital Are Associated With Neurologic Worsening in Patients With Large-Vessel Occlusion

Introduction: Decreases in blood pressure (BP) during thrombectomy are associated with infarct progression and worse outcomes. Many patients present first to a primary stroke center (PSC) and are later transferred to a comprehensive stroke center (CSC) to undergo thrombectomy. During this period, important BP variations might occur. We evaluated the association of BP reductions with neurological worsening and functional outcomes.

Methods: We prospectively collected hemodynamic, clinical, and radiographic data on consecutive patients with LVO ischemic stroke who were transferred from a PSC for possible thrombectomy between 2018 and 2020. We assessed systolic BP (SBP) and mean arterial pressure (MAP) at five time points: earliest recorded, average pre-PSC, PSC admission, average PSC, and CSC admission. We measured neurologic worsening as a change in NIHSS (ΔNIHSS) from PSC to CSC >3 and functional outcome using the modified Rankin Scale (mRS) at discharge and 90 days. Relationships between variables of interest were evaluated using linear regression.

Results: Of 91 patients (mean age 70±16 years, mean NIHSS 12) included, 13 (14%) experienced early neurologic deterioration (ΔNIHSS>3), and 34 (37%) achieved a good outcome at discharge (mRS<3). We found that patients with good outcome had significantly lower SBP at all five assessed time points compared to patients with poor outcome (Figure 1, p<0.05). Percent change in MAP from initial presentation to CSC arrival was independently associated with ΔNIHSS after adjusting for age, sex, and transfer time (p=0.03, β=0.27).

Conclusions: Patients with poor outcomes have higher BP throughout the pre-CSC period, possibly reflecting an augmented hypertensive response. Reductions in SBP and MAP before arrival at the CSC are associated with neurologic worsening. These results suggest that BP management strategies in the pre-CSC period to avoid large reductions in BP may improve outcomes in patients affected by LVO stroke.

Abstract 33: Qualitative Description of Ischemic Stroke Appearance on Low-Field, Point-Of-Care Magnetic Resonance Imaging

Background and Aims: Advances in low-field MRI have enabled image acquisition at the point-of-care (POC). We aim to characterize ischemic lesions in low-field, POC MRI and assess its relationship with stroke severity in ischemic stroke patients.

Methods: We performed POC MRI exams on ischemic stroke patients. T2-weighted (T2W), fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI) exams were acquired with a 64mT, portable bedside MRI system. Three raters computed signal intensity ratios (SIR) for each sequence. For every slice showing an infarct, an SIR was generated by dividing the mean signal intensity of the lesion by the mean signal intensity of the contralateral hemisphere. Infarct volumes were obtained by multiplying the lesion area of each slice by the slice thickness (5mm) and summing the cross-sectional areas. Volumes were correlated with National Institutes of Health Stroke Scale (NIHSS) scores at the time of scan.

Results: We studied 18 ischemic stroke patients (50% women; ages 30-95 years). Two patients were studied at two and three serial timepoints, respectively. POC exams were obtained 2.7 ± 2.2 days after symptom onset. A total of 18 T2W, 17 FLAIR, and 18 DWI exams were obtained. Three exams (1 T2W; 1 FLAIR; 1 DWI) were excluded due to motion degradation. High field MRI exams (19 ± 16 hours from POC exams) demonstrated ischemic infarcts in 15 of the 18 patients. All POC T2W and FLAIR exams revealed infarcts in these patients, and 14 of the 17 DWI exams showed infarcts. Ischemic infarcts were seen as hyperintense lesions (SIR: T2W = 1.19 ± 0.10, FLAIR = 1.15 ± 0.08, DWI = 1.36 ± 0.17). Infarct volume significantly correlated with NIHSS scores (T2W: r = 0.71, p < 0.01; FLAIR: r = 0.65, p < 0.05; DWI: r = 0.65, p < 0.05).

Conclusions: These preliminary data suggest that low-field, POC MRI may be useful in the clinical evaluation of ischemic stroke. Further work in larger cohorts is needed to elucidate the appearance of infarction on low-field imaging.

Direct carotid puncture for mechanical thrombectomy in acute ischemic stroke patients with prohibitive vascular access

OBJECTIVE

While the benefit of mechanical thrombectomy (MT) for patients with anterior circulation acute ischemic stroke with large-vessel occlusion (AIS-LVO) has been clearly established, difficult vascular access may make the intervention impossible or unduly prolonged. In this study, the authors evaluated safety as well as radiographic and functional outcomes in stroke patients treated with MT via direct carotid puncture (DCP) for prohibitive vascular access.

METHODS

The authors retrospectively studied patients from their prospective AIS-LVO database who underwent attempted MT between 2015 and 2018. Patients with prohibitive vascular access were divided into two groups: 1) aborted MT (abMT) after failed transfemoral access and 2) attempted MT via DCP. Functional outcome was assessed using the modified Rankin Scale at 3 months. Associations with outcome were analyzed using ordinal logistic regression.

RESULTS

Of 352 consecutive patients with anterior circulation AIS-LVO who underwent attempted MT, 37 patients (10.5%) were deemed to have prohibitive vascular access (mean age [± SD] 82 ± 11 years, mean National Institutes of Health Stroke Scale [NIHSS] score 17 ± 5, with females accounting for 75% of the patients). There were 20 patients in the DCP group and 17 in the abMT group. The two groups were well matched for the known predictors of clinical outcome: age, sex, and admission NIHSS score. Direct carotid access was successfully obtained in 19 of 20 patients. Successful reperfusion (thrombolysis in cerebral infarction score 2b or 3) was achieved in 16 (84%) of 19 patients in the DCP group. Carotid access complications included an inability to catheterize the carotid artery in 1 patient, neck hematomas in 4 patients, non-flow-limiting common carotid artery (CCA) dissections in 2 patients, and a delayed, fatal carotid blowout in 1 patient. The neck hematomas and non-flow-limiting CCA dissections did not require any subsequent interventions and remained clinically silent. Compared with the abMT group, patients in the DCP group had smaller infarct volumes (11 vs 48 ml, p = 0.04), a greater reduction in NIHSS score (-4 vs +2.9, p = 0.03), and better functional outcome (shift analysis for 3-month modified Rankin Scale score: adjusted OR 5.2, 95% CI 1.02-24.5; p = 0.048).

CONCLUSIONS

DCP for emergency MT in patients with anterior circulation AIS-LVO and prohibitive vascular access is safe and effective and is associated with higher recanalization rates, smaller infarct volumes, and improved functional outcome compared with patients with abMT after failed transfemoral access. DCP should be considered in this patient population.

Effects of Collateral Status on Infarct Distribution Following Endovascular Therapy in Large Vessel Occlusion Stroke

BACKGROUND AND PURPOSE

We aim to examine effects of collateral status and post-thrombectomy reperfusion on final infarct distribution and early functional outcome in patients with anterior circulation large vessel occlusion ischemic stroke.

METHODS

Patients with large vessel occlusion who underwent endovascular intervention were included in this study. All patients had baseline computed tomography angiography and follow-up magnetic resonance imaging. Collateral status was graded according to the criteria proposed by Miteff et al and reperfusion was assessed using the modified Thrombolysis in Cerebral Infarction (mTICI) system. We applied a multivariate voxel-wise general linear model to correlate the distribution of final infarction with collateral status and degree of reperfusion. Early favorable outcome was defined as a discharge modified Rankin Scale score ≤2.

RESULTS

Of the 283 patients included, 129 (46%) had good, 97 (34%) had moderate, and 57 (20%) had poor collateral status. Successful reperfusion (mTICI 2b/3) was achieved in 206 (73%) patients. Poor collateral status was associated with infarction of middle cerebral artery border zones, whereas worse reperfusion (mTICI scores 0-2a) was associated with infarction of middle cerebral artery territory deep white matter tracts and the posterior limb of the internal capsule. In multivariate regression models, both mTICI (P<0.001) and collateral status (P<0.001) were among independent predictors of final infarct volumes. However, mTICI (P<0.001), but not collateral status (P=0.058), predicted favorable outcome at discharge.

CONCLUSIONS

In this cohort of patients with large vessel occlusion stroke, both the collateral status and endovascular reperfusion were strongly associated with middle cerebral artery territory final infarct volumes. Our findings suggesting that baseline collateral status predominantly affected middle cerebral artery border zones infarction, whereas higher mTICI preserved deep white matter and internal capsule from infarction; may explain why reperfusion success-but not collateral status-was among the independent predictors of favorable outcome at discharge. Infarction of the lentiform nuclei was observed regardless of collateral status or reperfusion success.

Efficacy and safety of nerinetide for the treatment of acute ischaemic stroke (ESCAPE-NA1): a multicentre, double-blind, randomised controlled trial

BACKGROUND

Nerinetide, an eicosapeptide that interferes with post-synaptic density protein 95, is a neuroprotectant that is effective in preclinical stroke models of ischaemia-reperfusion. In this trial, we assessed the efficacy and safety of nerinetide in human ischaemia-reperfusion that occurs with rapid endovascular thrombectomy in patients who had an acute ischaemic stroke.

METHODS

For this multicentre, double-blind, randomised, placebo-controlled study done in 48 acute care hospitals in eight countries, we enrolled patients with acute ischaemic stroke due to large vessel occlusion within a 12 h treatment window. Eligible patients were aged 18 years or older with a disabling ischaemic stroke at the time of randomisation, had been functioning independently in the community before the stroke, had an Alberta Stroke Program Early CT Score (ASPECTS) greater than 4, and vascular imaging showing moderate-to-good collateral filling, as determined by multiphase CT angiography. Patients were randomly assigned (1:1) to receive intravenous nerinetide in a single dose of 2·6 mg/kg, up to a maximum dose of 270 mg, on the basis of estimated or actual weight (if known) or saline placebo by use of a real-time, dynamic, internet-based, stratified randomised minimisation procedure. Patients were stratified by intravenous alteplase treatment and declared endovascular device choice. All trial personnel and patients were masked to sequence and treatment allocation. All patients underwent endovascular thrombectomy and received alteplase in usual care when indicated. The primary outcome was a favourable functional outcome 90 days after randomisation, defined as a modified Rankin Scale (mRS) score of 0-2. Secondary outcomes were measures of neurological disability, functional independence in activities of daily living, excellent functional outcome (mRS 0-1), and mortality. The analysis was done in the intention-to-treat population and adjusted for age, sex, baseline National Institutes of Health Stroke Scale score, ASPECTS, occlusion location, site, alteplase use, and declared first device. The safety population included all patients who received any amount of study drug. This trial is registered with ClinicalTrials.gov, NCT02930018.

FINDINGS

Between March 1, 2017, and Aug 12, 2019, 1105 patients were randomly assigned to receive nerinetide (n=549) or placebo (n=556). 337 (61·4%) of 549 patients with nerinetide and 329 (59·2%) of 556 with placebo achieved an mRS score of 0-2 at 90 days (adjusted risk ratio 1·04, 95% CI 0·96-1·14; p=0·35). Secondary outcomes were similar between groups. We observed evidence of treatment effect modification resulting in inhibition of treatment effect in patients receiving alteplase. Serious adverse events occurred equally between groups.

INTERPRETATION

Nerinetide did not improve the proportion of patients achieving good clinical outcomes after endovascular thrombectomy compared with patients receiving placebo.

FUNDING

Canadian Institutes for Health Research, Alberta Innovates, and NoNO.

Fixed Compared With Autoregulation-Oriented Blood Pressure Thresholds After Mechanical Thrombectomy for Ischemic Stroke

Background and Purpose- Loss of cerebral autoregulation in the acute phase of ischemic stroke leaves patients vulnerable to blood pressure (BP) changes. Effective BP management after endovascular thrombectomy may protect the brain from hypoperfusion or hyperperfusion. In this observational study, we compared personalized, autoregulation-based BP targets to static systolic BP thresholds. Methods- We prospectively enrolled 90 patients undergoing endovascular thrombectomy for stroke. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy-derived tissue oxygenation (a cerebral blood flow surrogate) in response to changes in mean arterial pressure. The resulting autoregulatory index was used to trend the BP range at which autoregulation was most preserved. Percent time that mean arterial pressure exceeded the upper limit of autoregulation or decreased below the lower limit of autoregulation was calculated for each patient. Time above fixed systolic BP thresholds was computed in a similar fashion. Functional outcome was measured with the modified Rankin Scale at 90 days. Results- Personalized limits of autoregulation were successfully computed in all 90 patients (age 71.6±16.2, 47% female, mean National Institutes of Health Stroke Scale 13.9±5.7, monitoring time 28.0±18.4 hours). Percent time with mean arterial pressure above the upper limit of autoregulation associated with worse 90-day outcomes (odds ratio per 10% 1.84 [95% CI, 1.3-2.7] P=0.002), and patients with hemorrhagic transformation spent more time above the upper limit of autoregulation (10.9% versus 16.0%, P=0.042). Although there appeared to be a nonsignificant trend towards worse outcome with increasing time above systolic BP thresholds of 140 mm Hg and 160 mm Hg, the effect sizes were smaller compared with the personalized approach. Conclusions- Noninvasive determination of personalized BP thresholds for stroke patients is feasible. Deviation from these limits may increase risk of further brain injury and poor functional outcome. This approach may present a better strategy compared with the classical approach of maintaining systolic BP below a predetermined value, though a randomized trial is needed to determine the optimal approach for hemodynamic management.

Abstract TP11: CTA Collateral Status and Final Infarct Distribution Following Thrombectomy in Stroke Patients With Large Vessel Occlusion

Aim: The angiographic collateral status is a major predictor of final infarct volume in patients with large vessel occlusion (LVO). In this study, we assessed the effects of collateral status on final infarct lesion distribution after thrombectomy.

Methods: Acute ischemic stroke patients with occluded terminal ICA and/or MCA M1 segment who underwent thrombectomy and had a follow up MRI within a week were included. The angiographic collateral status was evaluated on pre-thrombectomy CTA and graded according to Miteff et al. (Brain 2009;132(8):2231-8). The final infarct lesion was segmented on DWI; and using voxel-wise general linear model, we determined the correlation of final infarct volume with post-thrombectomy TICI (thrombolysis in cerebral infarction) score, and collateral status - as a covariate.

Results: Among 106 patients with terminal ICA and/or MCA M1 occlusion in analysis, final infarct volume had a significant correlation with TICI reperfusion score (rho=0.384, p<0.001), CTA collaterals (rho=0.221, p=0.023), and TICIxCollaterals interaction term (rho=0.446, p<0.001). Voxel-wise analysis (Figure) showed that better reperfusion after thrombectomy (i.e. higher TICI) was associated with preservation of MCA territory cortex and deep white matter (green). The voxel-wise interaction analysis of TICI and CTA collateral status showed that poor collateral status is associated with infarction of the MCA-PCA border zone (red). Alternatively, good collaterals may preserve the peripheral edges of the MCA territory and MCA-ACA border zone (blue).

Conclusion: A successful thrombectomy in LVO stroke patients can preserve the cortical and deep white matter of MCA territory - including eloquent speech and motor regions - while CTA collateral status mainly determines the fate of the MCA-PCA border zone. On the other hand, lentiform nuclei tend to infarct despite successful reperfusion and good CTA collateral status.

Abstract TP40: Time From Stroke Onset to Reperfusion is Associated With Worse Functional Outcomes in Patients With Rapidly Progressing Infarcts

Introduction: Recent trials have demonstrated the benefit of endovascular therapy (EVT) beyond 6 hours of symptom onset. However, the importance of time to reperfusion (TTR) in the extended time window has recently been questioned. Given the variability of infarct growth rate (IGR), the time delay until reperfusion may have greater consequences for those with rapidly progressing infarcts, and identifying such patients is essential for improving outcomes. We tested the hypothesis that TTR is more closely associated with functional outcome in patients with rapidly progressing infarcts compared to their slow-progressing counterparts.

Methods: We retrospectively identified 106 patients at our center’s prospectively collected stroke database with anterior circulation large-vessel occlusion stroke and known time of symptom onset. Patients underwent initial CT perfusion imaging (CTP), EVT and and follow-up MRI at 24 hours. Core infarct volumes at presentation (CBF<30%) were estimated using RAPID software. The time between symptom onset and CTP was used to estimate IGR and to categorize patients as fast (≥5 mL/hour) or slow (<5 mL/hour) progressors. Alternatively, final infarct volume (FIV) was measured on MRI and used to calculate IGR in the absence of CTP. Functional outcome was assessed using the modified Rankin scale (mRS) at discharge and 90 days. Associations were computed using ordinal regression adjusting for age, ASPECTS, and TICI.

Results: 35 fast progressors (age 71±14, 17 F, TTR 288±91 minutes, mean IGR 21±24 mL/hour) and 71 slow progressors (age 71±17, 48 F, TTR 374±211 minutes, mean IGR 1.0±1.5 mL/hour) were identified. Fast progressors had higher admission NIHSS scores (18±6 vs 13±7, p<0.001) and significantly larger FIV (101±77 vs 47±65 mL, p<0.001). After adjusting for baseline factors, TTR was significantly associated with worse functional outcome at 90 days in fast progressors (p=0.026, aOR 1.13 per 10 minutes, 95% CI 1.02-1.28), but not for slow progressors (p=0.708).

Conclusions: In patients with rapidly progressing infarcts (≥5 mL/hour), TTR was associated with worse functional outcomes at 90 days compared to slow progressors. Identifying such patients may be critical for appropriate triage and rapid delivery of acute stroke care.

Abstract 117: Fixed Compared to Autoregulation-oriented Blood Pressure Thresholds After Mechanical Thrombectomy for Ischemic Stroke

Background: Loss of cerebral autoregulation in the acute phase of ischemic stroke leaves patients vulnerable to blood pressure (BP) changes. Effective BP management after endovascular therapy (EVT) may protect the brain from hypo- or hyperperfusion. In this observational study, we compared personalized, autoregulation-guided BP management with two commonly used clinical approaches: (1) maintaining BP below a fixed, pre-determined value and (2) stratifying BP thresholds based on reperfusion status.

Methods: We prospectively enrolled 90 patients undergoing EVT for stroke. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy-derived tissue oxygenation (a cerebral blood flow surrogate) in response to changes in mean arterial pressure (MAP). The resulting autoregulatory index was used to trend the BP range at which autoregulation was most preserved. Percent time that MAP exceeded the upper limit of autoregulation (ULA) or decreased below the lower limit of autoregulation (LLA) was calculated for each patient. Time above fixed SBP thresholds was computed in a similar fashion. Functional outcome was measured with the modified Rankin Scale (mRS) at 90 days.

Results: Personalized limits of autoregulation (LA) were successfully computed in all 90 patients (mean age 72 + 16, 47% female, mean NIHSS 14, mean monitoring time 28 + 18 hours). Percent time with MAP above the ULA associated with worse 90-day outcomes (OR per 10% 1.84, 95% CI 1.3-2.7, P=0.002), and patients suffering from hemorrhagic transformation spent more time above the ULA (10.9% vs. 16.0%, P=0.042). While there appeared to be a non-significant trend towards worse outcome with increasing time above SBP thresholds of 140 mmHg and 160 mmHg, the effect sizes were smaller compared to the personalized approach.

Conclusions: Non-invasive determination of personalized BP thresholds for stroke patients is feasible. Deviation from these limits may increase risk of further brain injury and poor functional outcome. This approach may present a better strategy compared to the classical approach of maintaining SBP below a pre-determined value, though a randomized trial is needed to determine the optimal approach for hemodynamic management.

Management of Hyperlipidemia After Stroke

PURPOSE OF REVIEW

Hyperlipidemia is a key therapeutic target for stroke risk modification. The goal of this review is to highlight available treatment options and review their efficacy in the setting of general cardiovascular disease and after most subtypes of ischemic stroke and hemorrhagic stroke.

RECENT FINDINGS

Statins remain first-line in the management of hyperlipidemia to prevent stroke. In recent trials of patients with pre-existing atherosclerotic vascular disease, new agents, most notably PCSK9 inhibitors and ezetimibe, added additional stroke risk reduction when combined with statins. Risk of stroke can be significantly reduced by understanding that hyperlipidemia is a key therapeutic target, particularly in patients with cardiovascular disease, and by identifying patients who may benefit from aggressive LDL-C reduction with statins ± novel agents.

Decreases in Blood Pressure During Thrombectomy Are Associated With Larger Infarct Volumes and Worse Functional Outcome

Background and Purpose- After large-vessel intracranial occlusion, the fate of the ischemic penumbra, and ultimately final infarct volume, largely depends on tissue perfusion. In this study, we evaluated whether blood pressure reduction and sustained relative hypotension during endovascular thrombectomy are associated with infarct progression and functional outcome. Methods- We identified consecutive patients with large-vessel intracranial occlusion ischemic stroke who underwent mechanical thrombectomy at 2 comprehensive stroke centers. Intraprocedural mean arterial pressure (MAP) was monitored throughout the procedure. ΔMAP was calculated as the difference between admission MAP and lowest MAP during endovascular thrombectomy until recanalization. Sustained hypotension was measured as the area between admission MAP and continuous measurements of intraprocedural MAP (aMAP). Final infarct volume was measured using magnetic resonance imaging at 24 hours, and functional outcome was assessed using the modified Rankin Scale at discharge and 90 days. Associations with outcome were analyzed using linear and ordinal multivariable logistic regression. Results- Three hundred ninety patients (mean age 71±14 years, mean National Institutes of Health Stroke Scale score of 17) were included in the study; of these, 280 (72%) achieved Thrombolysis in Cerebral Infarction 2B/3 reperfusion. Eighty-seven percent of patients experienced MAP reductions during endovascular thrombectomy (mean 31±20 mm Hg). ΔMAP was associated with greater infarct growth ( P=0.036) and final infarct volume ( P=0.035). Mean ΔMAP among patients with favorable outcomes (modified Rankin Scale score, 0-2) was 20±21 mm Hg compared with 30±24 mm Hg among patients with poor outcome ( P=0.002). In the multivariable analysis, ΔMAP was independently associated with higher (worse) modified Rankin Scale scores at discharge (adjusted odds ratio per 10 mm Hg, 1.17; 95% CI, 1.04-1.32; P=0.009) and at 90 days (adjusted odds ratio per 10 mm Hg, 1.22; 95% CI, 1.07-1.38; P=0.003). The association between aMAP and outcome was also significant at discharge ( P=0.002) and 90 days ( P=0.001). Conclusions- Blood pressure reduction before recanalization is associated with larger infarct volumes and worse functional outcomes for patients affected by large-vessel intracranial occlusion stroke. These results underscore the importance of BP management during endovascular thrombectomy and highlight the need for further investigation of blood pressure management after large-vessel intracranial occlusion stroke.

Abstract TP34: Malignant CT Perfusion Profile is Associated With Increased Sensitivity to Blood Pressure Reductions During Endovascular Stroke Therapy

Background: After large-vessel occlusion (LVO), blood flow to the ischemic penumbra largely depends on collateral perfusion. Blood pressure (BP) reductions during endovascular therapy (EVT) have been associated with increased infarct size and unfavorable functional outcome. We hypothesized that patients with poor collateral circulation assessed using CT perfusion imaging are at increased risk for infarct progression associated with intraprocedural BP reductions.

Methods: We prospectively enrolled 90 patients with LVO stroke who underwent perfusion imaging and EVT at two comprehensive stroke centers. Volumes of arterial tissue delay >10 seconds (ATD10) were estimated with RAPID software; a malignant profile was defined as ADT10 >100 ml. BP reduction was defined as the difference between baseline mean arterial pressure (MAP) at the start of EVT and the lowest MAP during the procedure. Sustained relative hypotension was calculated as the area between baseline MAP and continuous measurements of intraprocedural MAP.

Results: Sixty-seven patients (mean age 67 ± 15, 38 F, mean NIHSS 16) who were successfully revascularized (TICI 2B/3) were included in analysis. Mean baseline MAP was 119 ± 23 mmHg and median BP reduction was 28 (IQR 20 - 53). These values did not differ significantly among those with malignant (n=19) and non-malignant (n=48) collateral profiles, yet average infarct volume on follow-up was significantly greater among patients with poor collaterals (65 mL vs 32 ml) after adjusting for age and admission NIHSS (p=0.029). A significant interaction was found between the malignant collateral profile and intraprocedural BP reduction (p=0.02, Figure 1A&B).

Conclusions: Patients with malignant collateral profiles are more sensitive to BP reductions during EVT, leading them to develop significantly larger infarcts. These results emphasize the importance of intraprocedural blood pressure management for this at-risk group.

Abstract 95: Exceeding Personalized Blood Pressure Targets After Endovascular Stroke Therapy is Associated With Hemorrhagic Transformation and Worse Functional Outcome

Background: Effective blood pressure (BP) management after endovascular stroke therapy (EVT) is critical for maintaining optimal cerebral perfusion and to protect the brain from hyperperfusion. A single, universal BP target below 180/105 mmHg is likely inadequate in this highly heterogeneous patient population. We calculated individualized BP thresholds at which cerebral autoregulation was best preserved and analyzed how exceeding these limits correlates with hemorrhagic transformation (HT) and functional outcome.

Methods: 51 patients with large-vessel occlusion (LVO) stroke who underwent EVT were prospectively enrolled. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy and mean arterial pressure (MAP). The resulting autoregulatory index was used to identify and trend the BP range at which autoregulation was most preserved (Figure 1A). The percent time that MAP exceeded the upper limit of autoregulation (ULA) was calculated for each patient. HT was identified on CT imaging at 24 hours. Functional outcome was assessed using the modified Rankin Scale (mRS). Associations among percent time above ULA, HT and mRS were analyzed using ordinal or logistic regression, adjusting for age, TICI score and baseline NIHSS.

Results: Personalized limits of autoregulation could be computed in 36 patients (mean age 71±15, 12 F, mean admission NIHSS 15±6, average monitoring time 26±19 hours, HT=17). Optimal BP and limits of autoregulation were calculated for 83±11% of the total monitoring period. Percentage of time with MAP above ULA was associated with HT (p=0.016, OR 1.15, 95% CI 1.02-1.29) and worse functional outcome at discharge (p<0.004, OR 1.13, 95% CI 1.04-1.22) and 90 days (p=0.003, OR 1.22, 95% CI 1.06-1.38) (Figure 1B - D).

Conclusions: Non-invasive determination of personalized BP thresholds for LVO stroke patients is feasible; exceeding these limits may increase the risk of HT and worse clinical outcomes.

Abstract TP15: Percutaneous Transcarotid Puncture is a Viable Alternative for Thrombectomy in Acute Ischemic Stroke Patients With Difficult Vascular Access

Introduction: Although endovascular thrombectomy is a highly effective treatment for patients with large-vessel occlusion stroke, the procedure can be prolonged, or even impossible, due to difficult vascular access. We hypothesized that patients undergoing percutaneous transcarotid puncture (PTCP) as an alternative approach would have improved functional outcome compared to patients where a transfemoral approach was precluded.

Methods: For PTCP, a 6F (5.5-cm) sheath was placed in the common carotid artery using an ultrasound-guided, micropuncture technique. Mechanical thrombectomy (MT) was performed using stent retriever with adjunctive aspiration. We compared patients with unsuccessful MT due to transfemoral access failure with patients who were treated using PTCP. Functional outcome was assessed using the modified Rankin scale (mRS) at 3-months. Associations with outcome were analyzed using ordinal regression, adjusted for age and admission NIHSS.

Results: We included 34 patients in the study (82 years [SD 11], 25M, mean admission NIHSS 17). PTCP was performed in 20 cases. 14 patients who were well matched for age, gender and admission NIHSS served as historical controls. Carotid access was obtained in 19/20 patients (1 abandoned due to inability to safely cannulate the artery). Successful reperfusion (TICI 2b-3) was achieved in 16/19 (84%), with 28% achieving good outcome (mRS 0-3) at 90 days compared to 7% of historical controls (p=0.087, Figure 1). PTCP cases also had a trend toward smaller infarct volumes (median 10 vs 38 ml, p=0.084) and greater reduction in NIHSS (-3.4 vs +2.8, p= 0.083). A single patient suffered a fatal carotid blowout on post-MT day 4.

Conclusions: PTCP for emergent MT is a safe and effective strategy that yields high recanalization rates, and possibly improved functional outcome among patients with transfemoral access failure.

Abstract TP411: Distinct Systolic Blood Pressure Trajectories 72 Hours After Mechanical Thrombectomy Predict Hemorrhagic Transformation and Poor Functional Outcome

Introduction: Current stroke guidelines recommend maintaining systolic blood pressure (SBP) below 180 mmHg after thrombolysis, and this standard has carried over for post-thrombectomy blood pressure (BP) management. However, optimal BP management after mechanical thrombectomy (MT) remains unclear and BP beyond 24 hours after thrombectomy is not well-studied. We investigated how 72-hour SBP trajectories after MT may predict patient outcome.

Methods: We retrospectively studied patients with large-vessel occlusion stroke who underwent MT. BP was non-invasively recorded hourly for the first 72 hours. Hemorrhagic transformation (HT) was measured on 24-hour CT scans using ECASS II classification. Functional outcome was assessed using the modified Rankin Scale (mRS). SBP trajectories between groups were compared using generalized estimating equations. All analyses were adjusted for age, admission NIHSS, and recanalization status.

Results: Seventy-three patients (mean age 72±14, 40F, mean NIHSS 18) were analyzed. Patients with poor 90-day functional outcome (mRS >3) had higher mean SBP over the first 24 hours compared to those with favorable outcome (136 vs. 128 mmHg, p=0.017) and demonstrated distinct BP trajectories over the first 72 hours (Figure 1A). Patients with poor functional outcome had higher SBP directly after MT (155 vs. 141 mmHg) and their pressures dropped less during the first 12 hours when compared to those with favorable outcomes (p=0.018). Similarly, mean SBP and SBP trajectories of patients with HT were significantly different from those without HT (Figure 1B, p=0.050). By 72 hours, SBP trajectories were similar, regardless of functional outcome or HT.

Conclusions: During the first 72 hours after MT, acute ischemic stroke patients show distinct SBP trajectories, which differ in relation to functional outcome and hemorrhagic transformation. The findings may help recognize potential candidates for future blood pressure control trials.

Abstract WP3: Decreases in Blood Pressure During Endovascular Stroke Therapy are Associated With Larger Infarct Volumes and Poor Functional Outcome

Background: After large-vessel occlusion (LVO), the fate of the ischemic penumbra, and ultimately final infarct volume, largely depends on compensatory collateral perfusion. Blood pressure (BP) management is critical for avoiding cerebral hypoperfusion and further secondary neurological injury. In this study, we examined the effect of BP reductions and sustained relative hypotension during endovascular therapy (EVT) on infarct volume and functional outcome.

Methods: We retrospectively studied patients with LVO stroke who underwent mechanical thrombectomy. Intra-procedural MAP was monitored using a non-invasive BP cuff or an intra-arterial catheter. ΔMAP was calculated as the difference between admission MAP and lowest MAP during EVT. Sustained hypotension (aMAP) was measured as the area between admission MAP and continuous measurements of intra-procedural MAP until recanalization was achieved or procedure was completed. Final infarct volume was measured on MRI at 24hrs. Functional outcome was assessed using the modified Rankin Scale (mRS) at discharge and 90 days. Associations with outcome were analyzed using linear and ordinal regressions and adjusted for age, gender, admission NIHSS and TICI score.

Results: 262 patients (mean age 71±16, 58% F, mean NIHSS 17) were included in the analysis. Mean admission MAP was 106 mmHg. 86% of patients experienced ΔMAP reductions during EVT (mean 25±24 mmHg). ΔMAP was associated with larger final infarct volume (n=189, p=0.042). Median ΔMAP among patients with favorable outcomes (mRS 0-3) was 19 mmHg (IQR 3-39) compared to 33 mmHg (IQR 8-49) among patients with poor outcome (p=0.024). ΔMAP was independently associated with higher (worse) mRS scores at discharge (n=255, OR 1.013, 95% CI 1.004-1.023, p=0.008) and at 90 days (n=156, OR 1.014, 95% CI 1.001-1.023 p=0.034). The association between aMAP and outcome was highly significant at discharge (p=0.003) and 90 days (p=0.018).

Conclusions: BP reduction prior to recanalization may lead to larger infarct volumes and worse functional outcomes for patients affected by LVO stroke. These results underline the importance of BP management during EVT, and highlight the need for further investigation of active BP management strategies to optimize clinical outcomes.

Abstract TP277: The Neurointensivists’ Role in Management of Cerebral Venous Sinus Thrombosis

Introduction: Cerebral venous sinus thrombosis (CVST) represents an important cause of both ischemic and hemorrhagic strokes in young people. While recent guidelines recommend management in a stroke unit, the impact of Neurocritical care in this condition has not been studied. We aimed to assess whether the introduction of a Neurocritical Care program influenced clinical outcomes in CVST patients.

Methods: We retrospectively reviewed electronic medical records of adult patients admitted to Yale New Haven Hospital’s Neuroscience ICU (NICU) between 2010 and 2017 with a diagnosis of CVST. Demographics, vascular risk factors, comorbidities, length of stay and discharge modified Rankin scale (mRS) were collected. Patients were excluded for transfer after 24 hours of initial presentation. We compared two time periods, before (epoch 1, 2010-2012) and after (epoch 2, 2013-2017) the introduction of continuous staffing of CVST cases by neurointensivists in the NICU. Univariable and multivariable logistic regression were utilized to model the odds of poor outcome (dichotomized mRS 0-2 vs 3-6).

Results: Fifty-three patients with CVST met the inclusion criteria during the study period (mean age 39 (+/- 17) years, 51 % female). 20 patients were identified for Epoch 1 and 33 patients for Epoch 2. Overall, 40 patients (76%) had a good (mRS 0-2) outcome. For epochs 1 and 2, good outcomes were observed in 12 (60%) and 28 (85%) patients, respectively (p=0.04). In both univariable and multivariable regression analysis (adjusted for age and sex), admission during epoch 2 was associated with a significantly reduced odds of a poor outcome (OR 0.27, CI 0.07 - 0.98; p =0.048) and (OR 0.27, CI 0.07- 1; p=0.05), respectively.

Conclusions: In this small, single-center cohort of patients with CVST, most patients experienced a good outcome. The institution of continuous neurointensivist coverage was independently associated with better outcomes. Further validation in prospective, multicenter cohort studies is needed.

Missed Ischemic Stroke Diagnosis in the Emergency Department by Emergency Medicine and Neurology Services

BACKGROUND AND PURPOSE

The failure to recognize an ischemic stroke in the emergency department is a missed opportunity for acute interventions and for prompt treatment with secondary prevention therapy. Our study examined the diagnosis of acute ischemic stroke in the emergency department of an academic teaching hospital and a large community hospital.

METHODS

A retrospective chart review was performed from February 2013 to February 2014.

RESULTS

A total of 465 patients with ischemic stroke were included in the analysis; 280 patients from the academic hospital and 185 patients from the community hospital. One hundred three strokes were initially misdiagnosed that is 22% of the included strokes at the combined centers. Fifty-five of these were missed at the academic hospital (22%) [corrected] and 48 were at the community hospital (26%, P=0.11). Thirty-three percent of missed cases presented within a 3-hour time window for recombinant tissue-type plasminogen activator eligibility. An additional 11% presented between 3 and 6 hours of symptom onset for endovascular consideration. Symptoms independently associated with greater odds of a missed stroke diagnosis were nausea/vomiting (odds ratio, 4.02; 95% confidence interval, 1.60-10.1), dizziness (odds ratio, 1.99; 95% confidence interval, 1.03-3.84), and a positive stroke history (odds ratio, 2.40; 95% confidence interval, 1.30-4.42). Thirty-seven percent of posterior strokes were initially misdiagnosed compared with 16% of anterior strokes (P<0.001).

CONCLUSIONS

Atypical symptoms associated with posterior circulation strokes lead to misdiagnoses. This was true at both an academic center and a large community hospital. Future studies need to focus on the evaluation of identification systems and tools in the emergency department to improve the accuracy of stroke diagnosis.

Abstract W MP76: Diagnostic Accuracy and Characteristics of Missed Ischemic Strokes in the Emergency Department

Objectives: The failure to recognize an acute stroke in the ED represents a missed opportunity for potential thrombolytic therapy and for prompt treatment for secondary prevention. The aim of this study was to examine the diagnostic accuracy of acute ischemic strokes at a large academic center and to identify common characteristics of these missed strokes.

Methods: A retrospective review was performed on a random sample of patients >18 years old with a discharge diagnosis of ischemic stroke in 2013. All acute strokes were confirmed on CT or MRI. A stroke was “missed” if practitioners in the ED did not initially consider stroke in the differential, or the diagnosis was delayed causing the patient to miss the therapeutic window for thrombolytic therapy.

Results: Two hundred ischemic stroke patients were included in the study. The mean patient age was 72 years, and the mean initial NIHSS was 7. There were 36 “missed” strokes (18%) in this population. Of the strokes that were initially misdiagnosed, 20 of 36 (56%) presented in the time window for thrombolytic therapy and potentially could have received intervention. Posterior circulation strokes were more likely to be missed overall (20/58 posterior, 34%, vs 16/142 anterior, 11%, p < 0.001). Seventy-six percent of patients with posterior stroke had stroke in the original differential compared with 96% in those with anterior circulation stroke (p < 0.001). Symptoms independently associated with posterior circulation strokes included nausea/vomiting (OR=6.9, 95% CI: 2.0-23), headache (OR=6.4, 95% CI: 1.5-27) and difficulty walking (OR=3.5, 95% CI: 1.3-9.5). Anterior circulation patients more commonly presented with focal weakness (OR=0.11, 95% CI: 0.05-0.25) and aphasia (OR=0.17, 95% CI: 0.06-0.45).

Conclusions: Despite having a certified stroke program in a large academic medical center, 18% of acute ischemic strokes were missed in the ED. Posterior circulation strokes were 3 times more likely than anterior strokes to be missed. Posterior stroke patients were more likely to present with nausea/vomiting, headache and difficulty walking, and these symptoms should serve as triggers to consider ischemic stroke in the ED.

Abstract W P266: The Discharge Modified Rankin Score Correlates with Established Hemorrhagic Transformation Scores in Ischemic Stroke Patients Treated with Thrombolysis

Introduction: Several scores have been proposed to predict hemorrhagic transformation (HT) after IV r-tPA therapy. However, their utility in predicting adverse outcome has been limited to assessment of 30- or 90-day Modified Rankin Scale (mRS) scores, which are not readily available at many stroke centers. Studies evaluating discharge mRS scores as a predictor of long-term adverse patient outcome are lacking.

Hypothesis: We tested the hypothesis that HT scores predicting long-term adverse outcome after r-tPA therapy correlate with readily available discharge mRS scores.

Methods: Clinical data was analyzed from consecutive patients (n = 187) receiving IV r-tPA therapy from January 2009 until May 2013 at the Yale-New Haven Hospital. 8 HT scores were calculated for each patient: DRAGON, ASTRAL, Stroke-TPI, HAT Score, MSS, SITS-ICH, SEDAN and SPAN-100. Univariate logistic regression was performed using each HT score as an independent variable and discharge mRS≥5 or discharge mRS≥4 as the dependent variable. Receiver Operating Characteristic (ROC) analysis was used to test goodness of fit by the DeLong method.

Results: All metrics except the HAT Score and SPAN-100 showed good agreement with discharge mRS≥5 (ROC area > 0.7). The 3 HT scores showing the best agreement with discharge mRS≥5 were Stroke-TPI (ROC 0.85 ± 0.07), ASTRAL (ROC 0.85 ± 0.06) and DRAGON (0.83 ± 0.07), with odds ratios: Stroke-TPI (1.09 ± 0.03), ASTRAL (1.17 ± 0.06) and DRAGON (2.23 ± 0.58). These 3 HT scores still performed best when the discharge mRS cutoff was relaxed to mRS ≥ 4, with similar odds ratios but modestly reduced ROC areas: ASTRAL (ROC 0.82 ± 0.06), DRAGON (ROC 0.79 ± 0.07) and Stroke-TPI (ROC 0.76 ± 0.07).

Conclusions: Most established HT scores in our study showed good agreement with the discharge mRS score using two separate cutoff values. Therefore, readily available discharge mRS scores may be a useful predictor of adverse outcome following IV r-tPA therapy. These results warrant larger prospective studies to establish associations between discharge mRS scores and 90-day patient outcomes.

Abstract 197: The TeleStroke Mimic (TM) Score: A Prediction Rule for Identifying Stroke Mimics Evaluated in a Telestroke Network

Intro: Up to 30% of acute stroke evaluations are deemed stroke mimics (SM). SMs are likely common in telestroke as well, and a model to help a priori identify these patients might be clinically useful.

Methods: We used 829 consecutive patients from 01/04 to 04/13 in our internal New England based Partners TeleStroke Network for a derivation cohort and 332 cases for internal validation. External validation was performed on 226 cases from 01/08-08/12 in our Partners National TeleStroke Network. Performance of a prediction rule developed with stepwise logistic regression was characterized by ROC curve analysis.

Result: There were 23% SM in the derivation, 24% in the internal and 22% in external validation cohorts based on final clinical diagnosis. Compared to those with ischemic cerebrovascular disease (CVD), SM had lower mean age, fewer vascular risk factors, more often prior seizure and a different profile of presenting symptoms (Table 1). The TM-Score (Figure 1) was based on factors independently associated with SM status including age, medical history (atrial fibrillation, hypertension, seizures), facial weakness and NIHSS >14. The TM-Score performed well on ROC curve analysis (derivation cohort AUC=0.753, internal validation AUC=0.710, external validation AUC=0.770).

Conclusion: As telestroke consultation expands, increasing numbers of SM patients are being evaluated. These patients differ substantially from their ischemic CVD counterparts in their vascular risk profiles and other characteristics. Decision-support tools based on predictive models, like the one we propose, may help highlight these differences during complex, time-critical telestroke evaluations.

Abstract W P265: Improved Symptomatic ICH Rates for Ischemic Stroke Patients Receiving IV rtPA

Introduction: Symptomatic intracranial hemorrhage (sICH) is a concerning complication after the administration of IV r-tPA for treatment of acute ischemic stroke. Results from the NINDS trial demonstrated a 6.2% sICH rate. As such, acute stroke teams have used this data as a benchmark to compare their program’s complication rate related to IV r-tPA treatment in acute ischemic stroke.

Hypothesis: We examined the percent of acute ischemic stroke patients treated with IV r-tPA each year who developed sICH, and compared our sICH rate with the NINDS benchmark data for this adverse outcome. We anticipated that the sICH rate would decline with additional experience and expanded use of evaluation and treatment protocols at our institution.

Methods: Clinical data was analyzed from consecutive patients (n = 187) receiving IV rt-PA therapy from January 2009 until December 2012 at the Yale-New Haven Hospital. Adverse outcome was assessed by presence of symptomatic intracerebral hemorrhage (sICH). According to the NINDS definition, a hemorrhage was considered symptomatic if it was not seen on a previous CT scan and there had subsequently been either a suspicion of hemorrhage or any decline in neurologic status. The proportion of patients with sICH was calculated for each year and pairwise comparisons were made using two-sample tests of proportions.

Results: 18 out of 187 patients (9.6%) who received IV r-tPA therapy between 2009 and 2012 developed sICH after IV r-tPA treatment. When analyzed by year, 17.74% of sICH cases occurred in 2009, and this proportion decreased to 11.76% in 2010 (p-value = 0.4424), to 8.89% in 2011 (p-value = 0.1952) and to 2.86% in 2012 (p-value = 0.0329).

Conclusions: The proportion of ischemic stroke patients who were treated with IV rt-PA and subsequently developed sICH decreased each year from 2009 to 2012 at our center. This difference reached statistical significance by 2012. Our program’s expanded experience and focused approach using current guidelines and latest published practices likely explain the two-fold reduction in complication rates when compared to the NINDS benchmark. Further studies are warranted to compare our clinical decision-making protocol to proposed models for predicting adverse outcome after IV rt-PA therapy.

Decompressive hemicraniectomy for ischemic stroke in the pediatric population

Adult patients with space-occupying hemispheric infarctions have a poor prognosis, with an associated fatality rate of 80%. Decompressive hemicraniectomy (DH) has been studied as a treatment option for patients with malignant cerebral infarction refractory to maximal medical therapy, with reasonable outcomes demonstrated in the adult population if the patient is decompressed within 48 h. However, there are no randomized controlled trials in the pediatric literature to make the same claims. In this study, we evaluated the current literature in regards to DH following malignant stroke in the pediatric population. We found that excellent recovery, with an acceptable quality of life, is possible, particularly in the pediatric patient. Our cohort suggests that pediatric intervention beyond the 48-h time interval may still lead to positive outcomes, unlike adult patients. Regardless, randomized controlled trials are needed to determine optimal timing of intervention following symptom onset, as well as to identify predictors for positive outcome in the pediatric population.

Missed opportunities for recognition of ischemic stroke in the emergency department

INTRODUCTION

Evidence suggests that a significant number of patients discharged from the hospital with a diagnosis of ischemic stroke are not identified as having a stroke on admission. Those presenting with "nontraditional" stroke symptoms may be less likely to be diagnosed correctly. We aimed to establish whether there was an association between symptom presentation and diagnostic accuracy and to identify the type and frequency of nontraditional symptoms that resulted in a missed diagnosis in the emergency department.

METHODS

We reviewed the medical records of 189 patients discharged with a diagnosis of ischemic stroke from Yale-New Haven Hospital. We performed χ(2) analysis to determine whether an association existed between symptom presentation and diagnostic accuracy. Descriptive statistics allowed us to identify symptom type and frequency in patients with a missed diagnosis.

RESULTS

A diagnosis of suspected stroke was missed in 15.3% of patients who presented to the emergency department. We found a strong association (P < 0.0001) between symptom presentation and diagnostic accuracy. Of the patients presenting with any "traditional" symptom, 4% were missed. Of those presenting with only nontraditional symptoms, 64% were missed (odds ratio, 43.4; 95% confidence interval, 15.0-125.4). Nontraditional symptoms included generalized weakness, altered mental status, altered gait, and dizziness.

DISCUSSION

In order to facilitate appropriate management of patients with ischemic stroke, emergency nurses must be aware that symptom presentation is highly variable. Patients presenting with nontraditional symptoms may benefit from an immediate and comprehensive neurological evaluation.

Boosting enrollment in neurology trials with Local Identification and Outreach Networks (LIONs)

OBJECTIVE

Our purpose was to develop a geographically localized, multi-institution strategy for improving enrolment in a trial of secondary stroke prevention.

METHODS

We invited 11 Connecticut hospitals to participate in a project named the Local Identification and Outreach Network (LION). Each hospital provided the names of patients with stroke or TIA, identified from electronic admission or discharge logs, to researchers at a central coordinating center. After obtaining permission from personal physicians, researchers contacted each patient to describe the study, screen for eligibility, and set up a home visit for consent. Researchers traveled throughout the state to enroll and follow participants. Outside the LION, investigators identified trial participants using conventional recruitment strategies. We compared recruitment success for the LION and other sites using data from January 1, 2005, through June 30, 2007.

RESULTS

The average monthly randomization rate from the LION was 4.0 participants, compared with 0.46 at 104 other Insulin Resistance Intervention after Stroke (IRIS) sites. The LION randomized on average 1.52/1,000 beds/month, compared with 0.76/1,000 beds/month at other IRIS sites (p = 0.03). The average cost to randomize and follow one participant was $8,697 for the LION, compared with $7,198 for other sites.

CONCLUSION

A geographically based network of institutions, served by a central coordinating center, randomized substantially more patients per month compared with sites outside of the network. The high enrollment rate was a result of surveillance at multiple institutions and greater productivity at each institution. Although the cost per patient was higher for the network, compared with nonnetwork sites, cost savings could result from more rapid completion of research.

Regulated expression of CD36 during monocyte-to-macrophage differentiation: potential role of CD36 in foam cell formation

CD36 is an 88-kD integral membrane glycoprotein expressed on monocytes, platelets, and certain microvascular endothelium serving distinct cellular functions both as an adhesive receptor for thrombospondin, collagen, and Plasmodium falciparum-infected erythrocytes, and as a scavenger receptor for oxidized low-density lipoprotein and apoptotic neutrophils. In this study, we examined the expression of CD36 during in vitro differentiation of peripheral blood monocytes into culture-derived macrophages. Steady-state mRNA levels of CD36 showed a transient eightfold increase during monocyte-to-macrophage differentiation, peaking at the early macrophage stage (days 3 or 4 in culture), following a gradual decrease back to baseline levels by the mature macrophage stage (days 7 or 8 in culture). Immunoblotting with monoclonal antibodies to CD36 supported this transient, yet significant (8- to 10-fold) increase in total protein levels of CD36. The increased CD36 protein was observed at the plasma membrane, whereas an intracellular pool of CD36 was also detected from day 2 to day 6 in culture through indirect immunofluorescence. A concomitant twofold increase in the cells' ability to bind 125I-thrombospondin at the early macrophage stage (day 4) verified the functional competency of the plasma membrane localized CD36, and supported the presence of an intracellular pool of CD36. The in vitro differentiated macrophages as well as alveolar macrophages remained responsive to macrophage colony-stimulating factor (M-CSF), a known transcriptional regulator of monocyte CD36. The M-CSF-induced macrophages resulted in enhanced foam cell formation, which was inhibitable with monoclonal antibodies to CD36. Thus, the transient expression of CD36 during monocyte-to-macrophage differentiation, and the ability of M-CSF to maintain macrophage CD36 at elevated levels, may serve as a critical process in dictating the functional activity of CD36 during inflammatory responses and atherogenesis.