Last Known Well Research Articles

Abstract TP131: Factors Impacting Racial and Ethnic Disparities in the Use of Intravenous Thrombolytics in a Large Western US Healthcare System

Introduction: Studies of racial and ethnic disparities in using intravenous thrombolytics (IVT) for stroke in large healthcare systems and specific US states are lacking. This study examines potential contributors to disparities in IVT administration in a large Western healthcare system overall and by state (AK, CA, OR, TX and WA). Methods: This retrospective analysis of a systemwide stroke registry analyzed patients with ischemic stroke admitted January 2016 to September 2023. Patients aged <18 years, those arriving >4.5 hours from last known well (LKW), those with stroke occurring post hospital arrival and those receiving endovascular treatment were excluded. Generalized linear models were used to assess whether some racial and ethnic patient groups were less likely to receive IVT vs White patients, adjusting for age, National Institutes of Health Stroke Scale score at admission, LKW to arrival time, previous stroke, atrial fibrillation/flutter, obesity, mode of arrival, door-to–computed tomography scan time, insurance status and facility certification status. Results: Among 16,833 patients included, 45.0% received IVT. Overall, Black patients were less likely to receive IVT vs White patients ( Table 1 ), but this was not significant. By state, Black patients were less likely to receive IVT vs White patients in OR and WA ( Table 1 ). While Black and White patients had similar LKW to arrival times, Black patients were younger, had more severe strokes and used emergency medical service (EMS) at higher rates vs White patients ( Table 2 ). Compared with White patients, American Indian/Alaska Native patients were younger and used EMS at higher rates. Hispanic/Latino and Native Hawaiian/Pacific Islander patients were also younger and had more severe strokes than White patients. Conclusions: These data suggest that racial and ethnic disparities in stroke treatment vary by geography within a large healthcare system. Further analyses into the underlying factors are needed to guide tailored education at the local level.

LATE PRESENTATION OF STROKE PATIENTS TO TERTIARY CARE HOSPITALS THE UNDERLYING REASONS

Background: Stroke is a major neurological emergency and a leading cause of morbidity and mortality worldwide. Timely hospital presentation is crucial for effective treatment, including intravenous thrombolysis and endovascular therapy, both of which significantly improve outcomes. However, delays in hospital presentation remain prevalent, especially in resource-limited settings, due to socioeconomic, logistical, and awareness-related factors. Understanding these barriers is essential for implementing effective interventions to reduce prehospital delays and improve stroke care outcomes. Objective: To evaluate the awareness and knowledge of stroke patients and their companions presenting to a tertiary care hospital and to identify the common causes of prehospital delays. Methods: This cross-sectional retrospective study was conducted at Sheikh Zayed Hospital, Lahore, over six months, including 200 patients with ischemic or hemorrhagic stroke who met the inclusion criteria. Data were collected on variables such as age, sex, time since last known well (LKW), education level, knowledge of stroke symptoms, availability of transportation, lifestyle (urban or rural), and history of prior treatment. Patients younger than 18 or with non-stroke neurological conditions were excluded. Data were analyzed using SPSS version 25, with descriptive and inferential statistics calculated. The Chi-square test was applied to identify statistically significant associations. Results: The mean age of participants was 60.1 ± 18.5 years, with ischemic stroke comprising 76% (n = 152) of cases and hemorrhagic stroke 24% (n = 48). Among the cohort, 55% (n = 110) presented early (within 4 hours), while 45% (n = 90) presented late. A total of 70% (n = 140) of patients did not recognize stroke symptoms, and 75.3% (n = 151) reported lack of transportation as a barrier. Distance from the hospital affected 40.1% (n = 80) of rural patients, requiring over 45 minutes of travel. A statistically significant association was found between stroke knowledge and timing of hospital presentation (p = 0.013). Conclusion: A considerable proportion of stroke patients presented late to the hospital due to factors such as low literacy, reliance on public transportation, misinterpretation of symptoms, and low perceived severity of their condition. Addressing these barriers through targeted educational programs and systemic healthcare improvements is critical for enhancing timely access to stroke care.

Evaluation of Door-to-Needle Times Between Alteplase and Tenecteplase for Acute Ischemic Stroke at Two Academic Medical Centers.

Off-label tenecteplase use for acute ischemic stroke (AIS) has increased due to ease of administration and comparable efficacy and safety to alteplase. This study aimed to evaluate time to thrombolysis before and after transition from alteplase to tenecteplase for treatment of AIS at 2 institutions. This retrospective cohort study included adult patients receiving thrombolysis for AIS before and after transition from alteplase to tenecteplase at 2 academic medical centers from January 1, 2020 to January 31, 2024. The primary endpoint was door-to-needle (DTN) time, defined as minutes from hospital arrival to thrombolysis administration. Notable secondary endpoints included time from last known well (LKW) to thrombolysis, time from brain imaging to thrombolysis, hospital length of stay (LOS), and incidence of symptomatic intracranial hemorrhage (sICH). A total of 328 patients (168 tenecteplase and 160 alteplase) were included. Patients were 51.5% female with a median (interquartile range [IQR]) age of 70 [58-80] years and initial National Institutes of Health Stroke Scale (NIHSS) score of 8 [5-14]. There was no statistically significant difference in DTN time (60 vs 56 minutes), time from LKW to thrombolysis (134 vs 147.5 minutes), or time from brain imaging to thrombolysis (32 vs 31 minutes) between tenecteplase and alteplase. Hospital LOS (5.7 vs 4.9 days) and the rates of sICH (3% vs 3.8%) were similar between groups. Tenecteplase and alteplase had comparable DTN times for treatment of AIS and similar safety endpoints. Further studies are warranted to identify opportunities to streamline DTN times with tenecteplase.

Mismatch Vs No Mismatch in Large Core-AMatter of Definition.

Endovascular thrombectomy (EVT) has shown promise in randomized controlled trials (RCTs) for large ischemic core stroke patients, yet variability in core definition and onset-to-imaging time creates heterogeneity in outcomes. This study aims to clarify the prevalence and implications of core-perfusion mismatch (MM) versus no mismatch (No MM) in such patients, utilizing established imaging criteria. Aretrospective cohort study was conducted including patients from 7/29/2019 to 1/29/2023, with data extracted from acontinuously maintained database. Patients were eligible if they met criteria including multimodal CT imaging performed within 24 h from last known well (LKW), AIS-LVO diagnosis, and ischemic core size defined by specific rCBF thresholds. Mismatch was assessed based on different operational definitions from the EXTEND and DEFUSE 3trials. Fifty-two patients were included, with various time windows from LKW. Using EXTEND criteria, asignificant portion of early window patients exhibited MM; however, fewer patients met MM criteria in the late window. Defining MM using DEFUSE 3criteria yielded similar patterns, but with overall lower MM prevalence in the late window. When employing rCBF <38% as asurrogate for ischemic core, ahigher percentage of patients were classified as MM across both time windows compared to rCBF <30%. The prevalence of MM in large ischemic core patients varies significantly depending on the imaging criteria and time from LKW. Notably, MM was more prevalent in the early time window across all criteria used. Additional RCTs are needed to determine if this definition of MM identifies patients who will benefit most from EVT.

Contemporary Management of Acute Ischemic Stroke.

In the past decade, adding mechanical thrombectomy (MT) of intracranial arterial occlusions to intravenous (IV) thrombolysis has revolutionized the treatment of acute ischemic stroke (AIS) by expanding the therapeutic window to 24h. Treatment decisions require establishing a high probability of AIS; confirming time since last known well (LKW); assessing severity of the neurological deficit; determining any contraindications to IV thrombolysis; and performing neuroimaging, usually noncontrast computed tomography (NCCT), to exclude intracerebral hemorrhage. If time since LKW is less than 4.5h, patients with disabling stroke without contraindications can proceed immediately to IV thrombolysis while the decision about MT is under way. For some patients, the MT decision can be made on the basis of clinical assessment, NCCT, and CT angiography showing a large vessel occlusion. Others may require additional neuroimaging. Patients who are not candidates for IV thrombolysis within 4.5h or MT should be immediately evaluated for eligibility for extended-window IV thrombolysis or early antiplatelet treatment.

Abstract 267: Endovascular Thrombectomy in Patients with Anterior Circulation Stroke Presenting 6 Hours After Last Known Well: A Systematic Review and Meta‐analysis of 10 Randomized Clinical Trials

Background Several randomized trials have evaluated the benefits of endovascular thrombectomy (EVT) for anterior circulation large vessel occlusion strokes presenting beyond 6 hours of the last known well (LKW). We aimed to synthesize the results from these trials to provide high‐level evidence regarding EVT treatment for patients presenting in the late window. Methods A systematic search was conducted through four electronic databases, with no language restriction. Binary outcomes were analyzed using the risk ratio (RR) and 95% confidence interval (CI), while continuous outcomes were analyzed using the standardized mean difference (SMD) and 95% CI. Results Out of 2824 patients from 10 trials comparing EVT plus BMT and BMT alone among patients with AIS who presented beyond 6 hours of LKW, 1871 patients (n=981 EVT, n=890 BMT) were included in the analysis. The results showed benefits toward the EVT than BMT alone in Modified Rankin Scale (mRS) 0‐1 (RR= 1.84, p‐value &lt; 0.0001), mRS 0‐2 (RR= 2.3, p‐value= 0.0064), and mRS 0‐3 (RR= 1.64, p‐value &lt; 0.0001) at three months. No significant difference between EVT and BMT alone groups was found when analyzing either 90‐day mortality or symptomatic intracranial hemorrhage. Subgroup analysis showed that patients with large core stroke derived more benefits from thrombectomy than patients with non‐large core stroke in terms of 90‐day mRS 0‐2 (RR= 2.5, P‐value &lt; 0.0001). However, we did not find significant difference between perfusion vs non‐perfusion imaging modalities in 90‐day mRS 0‐2 and mortality. Conclusion These findings strengthen the previous evidence for the benefits of thrombectomy over medical treatment in managing patients with stroke, even with large ischemic regions in the late time window.

Utilization of Artificial Intelligence to Improve Door-In Door-Out Times for Mechanical Thrombectomy-Eligible Patients at a Hub-and-Spoke Community-Based Comprehensive Stroke Center: A Single Case Study Presentation

Background: Delays in the transfer of patients with hyperacute stroke may lead to treatment ineligibility due to the degree of cerebral hypoxic injury suffered. Cloud-based artificial intelligence applications may improve transfer times and expand access to advanced therapies. One case between a community-based comprehensive stroke center (CSC) and a primary stroke center (PSC) using a third-party telemedicine service and shared cloud-based artificial intelligence application may provide insight in opportunities to improve stroke systems of care. Case Presentation: A 62-year-old female with a past medical history of hypertension, current everyday tobacco smoker, and marijuana user presented to an outlying emergency department (ED) with dense left-sided hemiplegia affecting the arm and leg, right-sided gaze preference, and severe dysarthria. Her last known well (LKW) time was 0900 hours. CNS imaging revealed a right middle cerebral artery occlusion, visible to members of the CSC stroke team through the use of a cloud-based artificial intelligence cell phone application. The patient was treated with intravenous thrombolytics at the PSC, and she was transferred to the CSC, where she underwent a diagnostic cerebral arteriogram with carotid artery stenting. Later, Magnetic Resonance Imaging (MRI) of the brain revealed a 3.5 cm x 2.5 cm hemorrhagic lesion in the right frontal lobe and diffusion restriction in the right frontal and right posterior temporal lobes. The patient’s hospital stay was three days and, at the time of discharged, her modified Rankin score and NIHSS were zero. She was discharged on dual antiplatelet therapy, statin therapy, and nicotine replacement. Utilization of Artificial Intelligence: Transfer delays are complicated by organizing care at PSC and CSC and can be lengthy when communication across different facilities and subspecialties. Implementing cloud-based AI image sharing in stroke systems of care has reduced DIDO times by providing rapid imaging interpretation, streamlining communication, and enhancing coordination between PSCs and CSCs. Conclusions: Our case presentation showed how a hub-and-spoke model combined with cloud-based AI utilization can improve DIDO times and enhance stroke systems of care.

Including isolated aphasia improves sensitivity and negative predicative value for large vessel occlusion screening

BackgroundLarge Vessel Occlusion (LVO) screening tools provide objective assessments to guide diagnostic decisions during acute stroke activations. The Stroke VAN screening tool includes weakness, vision, aphasia, and neglect; however, only screens positive if weakness is present regardless of presence of other symptoms including isolated aphasia. The purpose of this project was to evaluate wAve, a modified Stroke VAN screening tool. WAve includes components of VAN with emphasis on isolated aphasia. MethodsWe conducted a retrospective cohort study on 376 persons who presented with stroke symptoms within 24 h of last known well (LKW) to the Emergency Department of an urban comprehensive stroke center in north central Texas between July 2019 and January 2020. Comparison of VAN and wAve predictive values was calculated using Chi square analysis. Sensitivity and specificity was checked by using MedCalc software. Data from the electronic medical record was obtained for analysis including a documented wAve score and a calculated VAN score. Results of CT angiogram diagnostic testing was used to determine congruence of screening results with evidence of LVO. Power analysis described by Hajian- Tilaki was used to estimate study size. ResultsResults included 192 positive wAve screens and 184 negative wAve screens compared to 152 positive VAN screens and 224 negative VAN screens. The sensitivities for wAve and VAN were 89 % and 80 % respectively. Negative predictive values for wAve and VAN were 97 % and 95 % respectively. In isolated aphasic person, one of eight presented with a LVO and received intervention. ConclusionThe team discovered more LVOs were identified with wAve than VAN in persons exhibiting isolated aphasia symptoms. Larger studies are needed to understand the role isolated aphasia plays in LVO detection.

Endovascular thrombectomy beyond 24 hours from last known well: a systematic review with meta-analysis

BackgroundDifferent studies have demonstrated the benefit of endovascular treatment (EVT) up to 24 hours after acute ischemic stroke (AIS) onset. Recent cohort observational studies suggest that patients with large vessel...

Sex differences in Wake-Up Stroke patients characteristics and outcomes.

Wake-up Stroke (WUS) accounts for about 25% of all ischemic strokes. Differences according to sex in the WUS subgroup has been poorly investigated so far, so we aimed to assess these differences by differentiating the enrolled population based on treatment administered. We retrospectively analysed clinical and imaging data of WUS patients admitted to our hospital between November 2013 and December 2018 dividing them in two groups: rTPA-treated and non-rTPA treated group. To point out outcome differences we evaluated: NIHSS at 7days or at discharge, mRS at discharge and ΔNIHSS. We enrolled 149 WUS patients, 74 rTPA treated and 75 non-rTPA treated. Among rTPA treated patients, time from last known well (LKW) to Emergency Department (ED) admission was longer in females than males (610 vs 454min), while females had a higher ΔNIHSS than males (5 vs 3). Finally, among non-rTPA treated patients, females were older than males (85 vs 79years), had a higher pre-admission mRS (although very low in both cases), had a longer length of stay (17 vs 13days) and shown a higher NIHSS at discharge (4 vs 2) compared to males. Females not receiving thrombolytic treatment had worse functional outcome than males, showing a higher NIHSS at discharge but, in contrast, when treated with rTPA they showed better neurological recovery as measured by a greater ΔNIHSS. We emphasize the importance of a prompt recognition of WUS in females since they seem to benefit more from rTPA treatment.

A Remote Consult Retinal Artery Occlusion Diagnostic Protocol

To report a novel protocol for diagnosis of retinal artery occlusions at the point of care using OCT and a remote consult model. Retrospective case series and evaluation of a diagnostic test or technology. Adult patients who presented with painless monocular vision loss and were diagnosed with a nonarteritic retinal artery occlusion. OCT machines were placed in the stroke center or emergency department at 3 hospitals within our health system. Patients who presented with painless monocular vision loss were evaluated by the stroke neurology service and an OCT was acquired. The images were interpreted remotely by the retina service. An in-house ophthalmology consult was not required to make the final treatment decision. Eligible patients were treated with intra-arterial tissue plasminogen activator (IA-tPA). Patients were followed by ophthalmology during their admission when an in-house consultation service was available or otherwise evaluated immediately after discharge. Visual acuity (VA) before and after treatment with IA-tPA; time from last known well (LKW) to treatment; and time from presentation to treatment. In the first 18 months since the protocol went live, 59 patients were evaluated. Twenty-five patients (42%) had a confirmed retinal artery occlusion based on OCT and follow-up examination. Ten patients were eligible for treatment, and 9 patients received treatment with IA-tPA. There was a statistically significant improvement in mean VA from logarithm of the minimum angle of resolution (logMAR) 2.14 to logMAR 0.7 within 24 hours after treatment (P= 0.0001) and logMAR 1.04 after 4 weeks (P= 0.01). Clinically significant improvement was noted in 66% of patients within 24 hours and maintained through 1 month in 56% of all treated patients. The mean time to treatment from LKW was 543 minutes and from presentation at the stroke center was 146 minutes. We report the successful implementation of a remote consult protocol using point-of-care automated OCT. This novel paradigm demonstrates the potential utility of remote consult services for the diagnosis of time-sensitive ophthalmic emergencies. Proprietary or commercial disclosure may be found after the references.

Abstract WP41: Last Know Well Documentation Gaps in the Hemorrhagic Stroke Patient Lessons Learned

Background: Intracerebral Hemorrhage (ICH) accounts for 10% of strokes and has higher risk for mortality and disability. Documentation of Last Known Well (LKW) for Ischemic stroke patients is firmly integrated in code-stroke processes to aid clinical decision making. Hematoma expansion may occur in ICH. LKW aids in time sensitive treatment modalities for BP management and anticoagulation reversal to reduce risk of neurological demise. LKW in ICH patients has not been well established as an important timely metric. Purpose: Translation of ICH guidelines into actionable metrics for data collection is needed to enhance outcomes. Methods: Twenty Comprehensive Stroke Centers participated in a three-year ICH learning collaborative from 2020-2022. Expanded ICH data elements were added to Get With The Guidelines® (GWTG)-Stroke registries to identify data gaps and facilitate quality improvement. Abstractors reviewed coding definitions and participated in American Heart Association® (AHA) National Office Hours to ensure data integrity. ICH data was reviewed quarterly. Records with Missing Times was one of fourteen measures analyzed; LKW documentation revealed low compliance. Findings: From 2020-2022 there were n=6,648 ICH patients entered, of that 49.1% did not have an LKW. Data was filtered by patient arrival mode to assess gaps. EMS arrival=33.7%, transfer from another hospital=55.4%, and private transport=58.5% had missing documentation. To understand documentation gaps, a fishbone diagram was used to illustrate causality. Contributing categories were as follows: patient demographics, resources, transfers, symptom presentation, clinical care, clinical specialty, and abstraction. Analysis of time sensitive treatments requiring LKW such as Anticoagulant Reversal for Direct Oral Anticoagulants (DOAC) showed 52 patients taking a DOAC on arrival did not have a LKW and were not reversed. Conclusions: Education and documentation strategies were implemented locally to optimize data capture. Providing scientific rationale for documenting LKW and its relationship to time sensitive interventions will be shared on a national level. Future considerations are to examine if adverse outcomes exist due to documentation and treatment gaps.

Abstract WP81: Patient Characteristics Between Last Known Well and Symptom Onset Time: Patterns in the Time is Brain Study

Background: Acute reperfusion treatment reduces morbidity in Acute Ischemic Stroke (AIS). National guidelines use Last Known Well (LKW) estimates to determine eligibility. When LKW and symptom onset (SO) are “coupled,” treatment eligibility determination is easier. However, eligibility becomes complex when times are “decoupled,” such as in wake-up strokes. We aimed to understand social differences in AIS patients with coupled vs decoupled LKW and SO times. Methods: Time is Brain is an ongoing, multicenter study assessing effects of social network dynamics on pre-hospital delay in socioeconomically disadvantaged stroke patients. Demographics, stroke characteristics, tPA administration, LKW, and SO times were collected from electronic medical records or interviews from Jan to Jul 2023. Symptom onset-to-door (OTD) times were calculated. Fourteen out of seventy patients diagnosed with intracerebral hemorrhage or transient ischemic attack were excluded. Fifty-six were divided into Coupled or Decoupled LKW/SO conditions. Mann-Whitney U , and Fisher’s exact or Pearson X 2 tests were performed. Significance was defined as p&lt;0.05. Results: Fifty-six patients diagnosed with AIS have been enrolled (mean age 67.0± 14.3, 54.3% Female, median NIHSS 2). 87.5% (n=49) self-identified as non-Hispanic and 17.9% (n=10) as Black. Fourteen patients had coupled and forty-two had decoupled LKW/SO times. Among those with decoupled times, 81.0% (n=34) had onset at home and 26.2% (n=11) awoke with symptoms. Cortical AIS was prevalent in both groups (58.8% v. 41.5%, p-value: 0.815). EMS use (58.8% v. 60.4%, p-value: 0.762) and tPA administration (23.5% v. 18.9%, p-value: 1.000) were comparable. Decoupled LKW/SO patients less commonly presented with dysarthria than coupled patients (29.4% v. 54.7%, p=0.036). Median OTD time of coupled v. decoupled groups was 458.5 v.105 min (IQR: 101.25-996.75 v. 60-390.0; p-value: 0.048). Conclusions: In our preliminary analysis of this multicenter cohort, three out of every four AIS stroke patients presented with decoupled LKW/SO times. Decoupling commonly occurred outside the wake-up stroke setting. Ongoing studies will discern patient-level social and clinical characteristics that describe these two important AIS populations.

Abstract 89: Portable, Low-Field Magnetic Resonance Imaging: Determining Mismatch Following Acute Ischemic Stroke

Background and Aims: Treatment options for acute ischemic stroke (AIS) are uniquely dependent on the time of stroke onset. Intravenous thrombolysis must be administered within 4.5 hours of symptoms commencing, yet a subset of patients wake-up with symptoms and time of onset is unknown. Mismatch between fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) MRI can be used to qualify wake-up strokes for thrombolysis. This has been shown to lead to improved functional outcomes in multicenter trials (WAKE-UP, MR-WITNESS). However, access to MRI is a barrier to differential diagnosis and subsequent treatment. Recent advances in portable, low-field MRI (LF-MRI) offer a solution to increase access to MRI technologies and circumvent the limitations of conventional systems. As such, in this pilot study, we sought to establish the utility of portable LF-MRI to identify DWI-FLAIR mismatch following AIS. Methods: Patients with a diagnosis of AIS presenting to Emergency Department or Intensive Care Unit of the Yale New Haven Hospital or Massachusetts General Hospital from January 2020 to June 2023 underwent DWI and FLAIR acquisition on a 0.064T MRI (Hyperfine Research Inc.) at &lt;4.5 hours ( n =7), 4.5-6 hours ( n =7), and 6-48 hours ( n =110) since last known well (LKW). Conventional high-field (HF) MR images were acquired within 72 hours of LF-MRI. HF-DWI images were co-registered to LF-FLAIR and the hyperintense DWI stroke lesion segmented and superimposed on the FLAIR. The segmentation was mirrored to the contralateral hemisphere of the LF-FLAIR to establish a FLAIR signal intensity ratio (SIR). Results: The FLAIR SIR on images &lt;4.5 hours since LKW was 0.98±0.08. The SIR for cases 4.5-6 hours was 1.34±0.33. Cases 6-48 hours produced a SIR of 1.56±0.36. The SIR at &lt;4.5 hours was significantly less than that observed &gt;6 hours since LKW ( p =0.03). Conclusion: This pilot study demonstrates that a 0.064T portable MRI is capable of distinguishing hyperacute stroke from later stroke onset using FLAIR SIR. Future research is needed in a larger cohort to determine if this imaging technology can be used to guide thrombolysis in the setting of wake-up stroke.

Abstract WP44: Assessing Timely Care of WI's Critical Access Hospitals Acute Stroke Patients With a Speed and Efficiency Task Force

Introduction: Data indicates that rural residents are at 30% higher risk of stroke. 2 Thirty percent of Wisconsin’s (WI) residents live in a rural area and are more often served by smaller, critical access hospitals (CAH). WI Coverdell Stroke Program (Coverdell) data entry into Get With The Guidelines-Stroke® (GWTG) for 2022 shows 22.3% of stroke patient’s transfer from a spoke, often CAH, to a larger tertiary or hub hospital. To assist Coverdell participating (CAH) in timely care of acute stroke patients, Coverdell, American Heart Association® (AHA), and 32 CAH’s partnered to form a Speed and Efficiency Taskforce (TF). Methods: An agreed upon charter, framework and data goals were established in May 2022. Metrics of EMS pre-notification, arrival to CT, and door to needle (DTN) times were regularly reviewed. Evaluation of patients arriving within 4.5 hours of last known well (LKW), median DTN, and percent DTN &lt; 60 minutes were analyzed in two arrival windows. Hypothesized differences when comparing arrival windows of 0700-1900 and 1901-0659 were that the 1901-0659 window would have extended treatment times due to lack of 24/7 CT coverage and LKW not validated from others. Results: Data analysis for 2022. N=179 • Arrival to CT: 10 minutes faster in 1901-0659 window • Median DTN: 3 minutes faster in 0700-1900 window (71 vs 74 minutes respectively) • % DTN within 60 minutes: 12% higher compliance in 0700-1900 window Conclusions: Coverdell CAH’s are initiating the CT in a timely manner. Times are lower for arrivals between 1901-0659, ruling out delays due to CT tech non-availability. Delays in DTN treatment times within 60 minutes of arrival are more significant in the 1901-0659 arrival timeframe. The potential causes are a delay in telestroke consult with decision to treat, internal hospital delays in mixing and delivering thrombolytics, CT availability, and family/significant others present. Further research regarding arrival time affecting treatment need to be considered.

Abstract 40: Relationship of Collateral Status With Clinical Outcomes in Endovascular Thrombectomy for Large Core Stroke: A SELECT2 Subanalysis

Background: Previous studies demonstrating association of collateral status with clinical outcomes after endovascular thrombectomy (EVT) excluded patients with large core infarcts. We analyzed the association of collateral status with clinical outcomes and EVT treatment effect in SELECT2. Methods: In SELECT2, a central core lab adjudicated CT-angiographic collateral status using collateral scores (CS) by Tan et al. Patients were stratified based on CS into poor (CS 0-1) vs good (CS 2-3) collaterals. The primary outcome was the distribution of modified Rankin Scale score at 90-day follow-up. Models were adjusted for core volume, ASPECTS in addition to age, stroke severity and time to randomization. Results: Of 352 patients, 180 received EVT. Median collateral status was 2(IQR 1-2). Patients presenting &lt;6h after last known well (LKW) (n=100) had poorer collaterals than those presenting at 6-24 hours (n=252), median 1 (1-2) vs 2 (1-2), p&lt;0.001. Collateral status inversely correlated with CTP core volume (Rho=-0.32, p&lt;0.0001), but not with CT ASPECTS (Rho=0.07, p=0.16). Overall, point estimates favored EVT in patients with poor (CS 0-1) [aGenOR: 1.32, 95% CI: 0.98-1.79, p=0.068] and good (CS 2-3) collaterals [aGenOR: 1.97, 95% CI: 1.43-2.72, p&lt;0.001] without significant heterogeneity [p-interaction=0.094]. However, in the earlier 0-6h time window, there was evidence of treatment effect hetermogeneity with a larger treatment effect when good collaterals were present [aGenOR: 4.10, 95% CI: 1.81-9.29] and an absent treatment effect when only poor collaterals were observed [aGenOR: 1.26, 95% CI: 0.79-1.99], p-interaction=0.023. In the late time window, (6-12h), the EVT treatment effect did not differ significantly between poor collaterals (aGenOR: 1.35, 95% CI: 0.91-2.01) and good collaterals (aGenOR: 1.78, 95% CI: 1.24-2.56, p-interaction=0.50). Conclusion: Collateral status was worse in large core patients presenting in early (&lt;6 hours) window; and correlated with ischemic core volume but not ASPECTS. Collaterals status modified EVT treatment effect in the early but not the late time window, in which both good and poor collaterals still benefited from EVT. Clinicaltrials.gov registration: NCT03876457

Abstract WP6: Safety Outcomes of Intravenous Tenecteplase in Tandem Occlusions Undergoing Mechanical Thrombectomy With Acute Stenting

Background: Studies have demonstrated that the addition of alteplase for patients with tandem lesions who underwent mechanical thrombectomy and acute stenting was safe with improved outcomes. We aimed to assess the safety and efficacy of Intravenous Tenecteplase (IV TNK) for patients with tandem lesions who undergo mechanical thrombectomy (MT) and acute stenting. Methods: Using a prospectively collected registry of stroke patients seen at our institution we identified patients who underwent mechanical thrombectomy and acute carotid stenting between January 2021 and May 2023. Primary outcomes included symptomatic intracranial hemorrhage (sICH) and parenchymal hematoma type 2 (PH-2). Secondary outcomes included favorable functional outcome (90-day modified Ranking score 0-2), 90-day mortality, successful reperfusion (modified Thrombolysis in Cerebral Infarction [TICI] score 2b-3) and median number of passes used. Outcomes were adjusted for age, NIHSS, ASPECTS, and last known well (LKW) time to arrival time. Results: A total of 86 patients were included of which 14 received IV TNK + MT with carotid stenting and 72 MT with carotid stenting alone. Patients who received IV TNK had lower median LKW to arrival time in minutes (133 [IQR 81-193] vs 575 [IQR 313-925], P&lt;0.001), and had higher ASPECTS median score (9 [9-10] vs 8 [7-9], P=0.03). There was 0% sICH vs 13.3% (p=0.36), and 0% PH-2 vs 4.2% (p&gt;0.999) in the IV TNK and the MT alone group, respectively. All patients who received tnk received intraprocedural eptifibatide loading dose and dual antiplatelets within 24 hours. Favorable functional outcomes were seen in 80.0% of IV TNK vs 58.2% of MT with carotid stenting alone (aOR 6.92 [0.45-105.7], p=0.16). Both groups had similar 90-day mortality rates 10% vs 9.1% (aOR 0.59 [0.01-34.9], p=0.8), number of passes 1 [1-2] vs 2 [1-3], (P=0.09), and successful reperfusion (TICI score 2b-3) 100% vs 98.6% (p&gt;0.999). Conclusion: Our study shows that the combination of IV TNK and MT with acute stenting for tandem lesions did not increase the risk of sICH or PH-2. IV TNK group did not have statistically significant differences in our secondary outcomes as well. However, the sample size was low, and this patient population needs to be studied in a larger group.

Abstract TP246: Circadian Variability of the Clot Burden Score in Acute Anterior Circulation Ischemic Stroke

Background/Purpose: Fibrinolytic activity in blood plasma displays a circadian rhythm with a drop in the morning hours that may predispose to acute thrombotic events. The Clot Burden Score (CBS) is a semiquantitative measure on CT angiography (CTA) of thrombus extent in proximal anterior circulation strokes that has been correlated with functional outcome. Higher clot burden has also been shown to have lower recanalization rates with intravenous thrombolytics. We aimed to investigate whether CBS is a parameter that displays circadian variability. Methods: We performed a retrospective analysis on consecutive stroke patients presenting &lt;24 hours from symptom onset or last known well (LKW) with an occlusion in the anterior circulation confirmed on CTA. CBS was scored on a 10-point negative ordinal scale with 2-points subtracted for occlusion of the supraclinoid ICA, proximal M1, or distal M1, and 1-point subtracted for occlusion of the infraclinoid ICA, A1, or either M2 branches. No points were subtracted for occlusion distal to A1 or M2. Subjects were grouped into four 6-hour intervals, MORNING: 6:00-11:59, DAY: 12:00-17:59, EVENING: 18:00-23:59, and NIGHT: 0:00-5:59, based on the time of onset/LKW. CBS values were compared between groups using the Kruskal-Wallis test with pairwise comparisons. Results: 240 subjects were included with median age of 75 (IQR 65-84), NIHSS score of 17 (IQR 10-24), and time from onset/LKW to CTA of 5 hours (IQR 2-11). 73 subjects had onset during the MORNING, 56 during the DAY, 86 during the EVENING, and 25 during the NIGHT. The median CBS from MORNING time onset was 6 (IQR 5-9), compared to 7 (IQR 6-9) from the DAY, 7.5 (IQR 6-9) from the EVENING, and 7 (IQR 5-8.5) from the NIGHT. CBS was significantly lower in the MORNING compared to the EVENING, p=0.037. CBS was not significantly different between all other pairwise comparisons, p&gt;0.107. Conclusion: CBS as a measure of thrombus extent in proximal anterior circulation strokes on CTA appears to show circadian variability, with lower scores (higher clot burden) during MORNING onset (6:00-11:59) than the EVENING (18:00-23:59). This may have implications for future studies of chronotherapeutic protocols.

Plasma symmetric dimethylarginine as a metabolite biomarker of severe acute ischemic stroke.

After severe ischemic stroke (IS), circulating levels of symmetric dimethylarginine (SDMA) increase. We investigated the early dynamics of SDMA in stroke to potentially aid with prehospital identification of severe IS from hemorrhagic stroke (HS). We performed targeted mass spectrometry (MS) measurements of SDMA in two sequential acute plasma samples (early and secondary) of 50 IS patients with LVO and 49 HS patients. Secondary samples of 227 IS and 84 HS patients with moderate to severe symptoms (NIHSS ≥ 7) subsequently underwent ELISA validation. The median (IQR) last-known-well (LKW) to sampling times were 43 min (35-67) for early samples in the MS analysis, and 83 min (65-113) for secondary samples in MS and ELISA analyses. No inter-group differences existed in early samples, but IS patients had significantly higher mean (IQR) SDMA levels in secondary samples in both analyses: 5.8 (5.3-6.9) vs. 5.1 (4.2-5.8) A.U. for HS, p < 0.001, with MS; and 0.82 (0.72-1.01) vs. 0.71 (0.58-0.85) nmol/mL for HS, p < 0.001, with ELISA. For IS patients, higher SDMA levels were associated with cardioembolic stroke: 0.84 (0.73-1.09) vs. 0.79 (0.71-0.91) nmol/mL for other etiologies, p = 0.042, and poor outcome: modified Rankin Scale (mRS) 4-6; 0.90 (0.73-1.06) vs. 0.80 (0.72-0.97) nmol/mL for mRS 0-3 (p = 0.045). In a large clinical cohort of stroke patients with moderate to severe symptoms, our data suggest that SDMA can assist in differentiation of IS and HS patients already 1 h and a half after symptom onset. SDMA may prove to have future value in a diagnostic stroke biomarker panel.

Serum apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) is a novel stroke biomarker

BackgroundApoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) is a promising stroke biomarker. However, a large study of human serum ASC has not yet to be reported; additionally, the diagnostic value of prehospital concentration and practicality of ASC remains unknown. MethodsWe recruited 774 Chinese stroke patients, including 523 with ischemic stroke (IS) and 251 with hemorrhagic stroke (HS) within 14 days following symptom onset in the emergency department, alongside 481 healthy individuals and 64 cognitive impairment patients as controls. Serum ASC concentrations were determined using automated chemiluminescence immunoassay, exploring the relationship between serum ASC concentration and subtypes, severity, and sampling timepoints of stroke. ResultsASC concentrations were significantly higher in stroke patients compared with all controls (P < 0.001). HS patients had greater ASC concentrations than IS patients (P < 0.05). With increasing ASC concentration, the proportion of severe cases increased. The area under the receiver operating characteristic curve (AUC) for differentiating between healthy individuals and stroke patients in the hyperacute phase was 0.78; this markedly improved (0.90) when considering samples from healthy individuals and patients with subarachnoid hemorrhage (SAH) ≤ 3 h from last-known-well (LKW). ConclusionsSerum ASC is a valuable biomarker for stroke differentiation and aids in the clinical diagnosis of stroke severity and subtypes.