Abstract WP46: Emergent Large Vessel Occlusion Direct Triage Model Outcomes: A Systematic Review And Meta-Analysis

Introduction: There has been a shift in prehospital systems of care to prioritize transporting acute ischemic stroke (AIS) patients with suspected emergent large vessel occlusion (ELVO) stroke to thrombectomy capable stroke centers (TSCs), as opposed to primary stroke centers (PSCs) which may be closer and offer intravenous thrombolysis faster. Large scale data on clinical outcomes in direct triage are lacking.

Methods: We conducted a systematic review and meta-analysis using PRISMA guidelines with the Nested Knowledge AutoLit platform to search PubMed for relevant terms from 01/2015 to 05/2022. Our primary endpoint was proportion of patients with a good clinical outcome [modified Rankin Score (mRS) 0-2] at 90 days.

Results: We identified 390 studies, 16 of which compared direct triage to various models and were included. Amongst these, Mobile Stroke Unit (MSU; n=1), Mothership only (n=1), Drip-and-Ship only (n=3), and Mothership + Drip-and-Ship (n=11) were compared to Direct Triage. Among the eleven that reported 90-day functional status outcomes, there were no discernible trends. Four studies that compared 90-day functional outcomes amongst patients who received EVT and compared Direct Triage to Drip-and-Ship + Mothership models were analyzed. Baseline age, sex, and presenting NIHSS were similar. Patients who underwent Direct Triage were more likely to have a good outcome (mRS 0-2) at 90-days (OR 1.35, 95% CI 1.03-1.76).

Conclusions: Amongst patients who received EVT, patients who underwent Direct Triage were more likely to have better functional outcomes at 90 days. Direct Triage of AIS patients is a promising strategy to improve clinical outcomes in patients who undergo EVT. More research is needed in patients who do not receive EVT.

AI software detection of large vessel occlusion stroke on CT angiography: a real-world prospective diagnostic test accuracy study

BACKGROUND

Artificial intelligence (AI) software is increasingly applied in stroke diagnostics. However, the actual performance of AI tools for identifying large vessel occlusion (LVO) stroke in real time in a real-world setting has not been fully studied.

OBJECTIVE

To determine the accuracy of AI software in a real-world, three-tiered multihospital stroke network.

METHODS

All consecutive head and neck CT angiography (CTA) scans performed during stroke codes and run through an AI software engine (Viz LVO) between May 2019 and October 2020 were prospectively collected. CTA readings by radiologists served as the clinical reference standard test and Viz LVO output served as the index test. Accuracy metrics were calculated.

RESULTS

Of a total of 1822 CTAs performed, 190 occlusions were identified; 142 of which were internal carotid artery terminus (ICA-T), middle cerebral artery M1, or M2 locations. Accuracy metrics were analyzed for two different groups: ICA-T and M1 ±M2. For the ICA-T/M1 versus the ICA-T/M1/M2 group, sensitivity was 93.8% vs 74.6%, specificity was 91.1% vs 91.1%, negative predictive value was 99.7% vs 97.6%, accuracy was 91.2% vs 89.8%, and area under the curve was 0.95 vs 0.86, respectively. Detection rates for ICA-T, M1, and M2 occlusions were 100%, 93%, and 49%, respectively. As expected, the algorithm offered better detection rates for proximal occlusions than for mid/distal M2 occlusions (58% vs 28%, p=0.03).

CONCLUSIONS

These accuracy metrics support Viz LVO as a useful adjunct tool in stroke diagnostics. Fast and accurate diagnosis with high negative predictive value mitigates missing potentially salvageable patients.

Abstract 74: Area Deprivation Index, Stroke Outcomes, And Structural Changes To Improve Access To Thrombectomy

Introduction: In New York City (NYC), expanding the reach of thrombectomy-capable stroke centers (TSC) is key to combating socioeconomic disparities in stroke care. The Area Deprivation Index (ADI), a validated, neighborhood-level composite measure (scored 1-100) that includes income, education, employment, and housing quality, has informed healthcare delivery but has not been used to identify disadvantaged neighborhoods with poor access to stroke care. We sought to evaluate the impact of establishing Mount Sinai Queens Hospital (MSQ) as a TSC in 2017 on transfer times and to explore the association between ADI and stroke care access.

Methods: Thrombectomy patient pick-up addresses were obtained through Emergency Medical Services runsheets from June 2016 to July 2021 and matched to census-tract level ADI scores from Neighborhood Atlas. Preliminary analyses compared both ADIs and time to stroke care access in both Queens and Manhattan. The primary outcome measure was the duration between ambulance arrival and groin puncture. Simple linear regression and T-tests were used to assess the association between ADI and time to groin puncture by borough.

Results: Among 517 cases between 2016-2021, the average ADI of pick-up locations was 10.35 (range: 1 - 70.5). Across all centers, higher ADI (greater deprivation) was significantly associated with increased time to groin puncture (p = 0.024). Notably, Queens patients were picked up in census tracts with higher ADI (p=0.0289) but had a faster pick up to groin puncture time (p=0.006).

Conclusions: Across urban census tracts, a higher ADI was associated with delays in access to thrombectomy. Thrombectomy centers in areas with higher ADI can play a role in reducing healthcare disparities for stroke patients.

Repeated Mechanical Endovascular Thrombectomy for Recurrent Large Vessel Occlusion: A Multicenter Experience

BACKGROUND AND PURPOSE

Mechanical thrombectomy (MT) is now the standard of care for large vessel occlusion (LVO) stroke. However, little is known about the frequency and outcomes of repeat MT (rMT) for patients with recurrent LVO.

METHODS

This is a retrospective multicenter cohort of patients who underwent rMT at 6 tertiary institutions in the United States between March 2016 and March 2020. Procedural, imaging, and outcome data were evaluated. Outcome at discharge was evaluated using the modified Rankin Scale.

RESULTS

Of 3059 patients treated with MT during the study period, 56 (1.8%) underwent at least 1 rMT. Fifty-four (96%) patients were analyzed; median age was 64 years. The median time interval between index MT and rMT was 2 days; 35 of 54 patients (65%) experienced recurrent LVO during the index hospitalization. The mechanism of stroke was cardioembolism in 30 patients (56%), intracranial atherosclerosis in 4 patients (7%), extracranial atherosclerosis in 2 patients (4%), and other causes in 18 patients (33%). A final TICI recanalization score of 2b or 3 was achieved in all 54 patients during index MT (100%) and in 51 of 54 patients (94%) during rMT. Thirty-two of 54 patients (59%) experienced recurrent LVO of a previously treated artery, mostly the pretreated left MCA (23 patients, 73%). Fifty of the 54 patients (93%) had a documented discharge modified Rankin Scale after rMT: 15 (30%) had minimal or no disability (modified Rankin Scale score ≤2), 25 (50%) had moderate to severe disability (modified Rankin Scale score 3-5), and 10 (20%) died.

CONCLUSIONS

Almost 2% of patients treated with MT experience recurrent LVO, usually of a previously treated artery during the same hospitalization. Repeat MT seems to be safe and effective for attaining vessel recanalization, and good outcome can be expected in 30% of patients.

Abstract P129: Initial Real-World Experience With Viz LVO in Transferred Large Vessel Occlusion Stroke Patients

Background and Purpose: Randomized controlled trials have demonstrated the importance of time to endovascular therapy (EVT) on clinical outcomes in large vessel occlusion (LVO) acute ischemic stroke. Delays to treatment are particularly prevalent when patients require a transfer from hospitals without EVT capability onsite. A novel computer aided triage system, Viz LVO, has the potential to streamline workflows. This platform includes an image viewer, communication system, and an artificial intelligence (AI) algorithm that automatically identifies suspected LVO strokes on CTA imaging and rapidly triggers alerts. We hypothesize that the Viz application will decrease time-to-treatment.

Methods: A prospective database was assessed for patients who presented to a stroke center utilizing Viz LVO in the Mount Sinai Health System in New York and underwent EVT following transfer for LVO stroke between July 2018 and March 2020. This time period was chosen due to the COVID-19 pandemic affecting stroke workflow after March 2020. Time intervals were compared for 55 patients divided into Pre- and Post-Viz cohorts.

Results: The median initial door-to-neuroendovascular team (NT) notification time interval was significantly faster (25.0 minutes [IQR=12.0] vs 40.0 minutes [IQR=61.0]; p=0.01) with significantly less variation (p<0.05). The median initial door-to-skin puncture time interval was 25 minutes shorter in the Post-Viz cohort, although not statistically significant (p=0.15). Post Viz LVO implementation, the Viz notification was the first NT notification 38% (10/26) of the time.

Conclusions: Our preliminary results have shown that Viz LVO implementation is associated with earlier, more consistent NT notification times and potentially treatment times. This platform presents a novel application of AI that can serve as an early warning system and a failsafe to ensure that no LVO is left behind. Further studies are warranted.

Abstract P125: The First Year of Pre-Hospital Triage for Emergent Large Vessel Stroke Across a Large New York City Health System

Introduction: On April 1 2019, New York City EMS began a triage protocol using a modified Los Angeles Motor Scale (S-LAMS for addition of speech) to identify potential endovascular thrombectomy (EVT) eligible patients in the field (S-LAMS 4-6 with last known well (LKW) <5 hours). These patients are routed to the nearest thrombectomy capable center, driving past potentially closer primary stroke centers.

Methods: Patients brought by EMS to a large multicenter health system across NYC for the year following April 1, 2019 were extracted from a prospectively collected stroke database. S-LAMS triage positive (STP) patients were assessed for diagnostic accuracy and treatment times. They were compared with a cohort that underwent EVT during the same period, but triaged as S-LAMS triage negative (STN).

Results: STP patients (N=145) were 56.6% women, mean age of 70, median baseline mRS of 0, S-LAMS score of 5, and arrival NIHSS of 13. Stroke was diagnosed in 110 (75.8%) patients, 32 intracerebral hemorrhage and 78 ischemic. Of the ischemic, 45 were large vessel occlusion stroke (ELVO) and 34 underwent EVT (PPV of 0.31 for ELVO). STN patients (N=65) with LKW of < 5 hours were brought by EMS and underwent EVT; 34 were brought directly to EVT capable centers, and 36 required transfer for EVT. Mean time to hospital arrival from EMS scene arrival was significantly longer for STP patients than STN patients (38 vs. 29 minutes, p<0.01). Mean ambulance travel time was significantly longer for STP patients than STN patients (10 vs. 7 minutes, p<0.01). Mean tPA administration time from EMS scene arrival was not significantly different between STP (N=41) and STN patients (N=40) (90 vs. 91 minutes, p=0.89). Mean arterial access time for EVT from EMS scene arrival was significantly shorter for STP patients than STN patients (137 vs. 200 minutes, p<0.01).

Conclusions: Pre-hospital stroke triage using the streamlined S-LAMS scale is comparable with other pre-hospital scales in predictive value for ELVO. While pre-hospital evaluation and transport times are longer, they add minimal delay to the hospital arrival, do not affect tPA times, and improve times to EVT in a large, urban environment. Further analysis on effect of the triage protocol on patient outcomes is warranted.

Abstract MP21: Mobile Interventional Stroke Teams Lead to Improved Outcomes in the Early Time Window for LVO Stroke

Introduction: Endovascular therapy (EVT) for large vessel occlusion (LVO) stroke is time-sensitive. At Mount Sinai Health System, we developed a novel Mobile Interventional Stroke Team (MIST) that travels to Thrombectomy Capable Stroke Centers to perform EVT, as opposed to transferring patients in the Drip-and-Ship (DS) model. We have shown significantly faster initial door-to-recanalization times and improved discharge outcomes. The effect of the MIST stratified by time of presentation has yet to be studied.

Hypothesis: In patients presenting with a last known well [LKW] of <6 hours, the MIST model leads to better clinical outcomes as compared to the DS model.

Methods: In a prospectively collected stroke database at a multicenter health system, patients undergoing EVT performed by a MIST or after transfer in a DS model from January 2017 to March 2020 with baseline mRS 0-2 were selected. Patients presenting in the early time window and late time window (LKW >6 hours) were analyzed separately. The primary endpoint was the proportion with a good outcome (mRS of 0-2) at 90 days. Secondary endpoints included discharge NIHSS and mRS.

Results: In the 242 selected patients, the MIST and DS cohorts were similar in age, gender, initial NIHSS, pre-stroke mRS, and procedural details. In the early window, 54% (39/72) had a good 90-day outcome in the MIST model, as compared to 28% (25/88) in the DS model (p<0.01). In the late window, good 90-day outcomes were similar (29% vs 43%; p=0.40). The median NIHSS at discharge was 4.0 and 12.0 in the early window (p<0.01) and 5.0 and 11.0 in the late window (p=0.16) in the MIST and DS models, respectively. The early window discharge mRS was significantly better in the MIST model (p<0.01) and similar in the late window (p=0.74).

Conclusions: The MIST model used in the early time window produces better 90-day outcomes compared to the DS model. This is likely due to the MIST’s ability to capture fast progressors in the early window.

Abstract TP38: Re-Occlusion During Endovascular Therapy for Acute Stroke Patients With Large Vessel Occlusion

Introduction: Endovascular Therapy (EVT) has demonstrated significant benefits for selected acute ischemic stroke (AIS) with emergent large vessels occlusion (ELVO). Early recanalization is one of the most significant predictors of favorable outcome. However, re-occlusion during the procedure remains a challenge and may prolong the time needed for recanalization in a subset of patients. We planned to explore the clinical, radiographic and laboratory features that are associated with intra-procedural re-occlusion.

Method: We retrospectively reviewed consecutive patients who received EVT for ELVO in a single academic health system. Re-occlusion was defined if the occluded target vessel recanalized with TICI ≥2, but became TICI<2 on repeated diagnostic angiography. T test/Wilcoxon test and Chi-square were used to compare risks factors, atherosclerotic plaque burden, and coagulation profile (obtained prior to procedure) between patients with and without re-occlusion.

Results: Among 265 patients (male 46.4%, mean age 69 ±14.4 year old), 25 patients had re-occlusion intra-operatively. The history of cardiovascular risks factors (HTN, HLD, DM, smoking, atrial fibrillation), prior use of antiplatelets or antithrombotics, the number of cerebral arteries with atherosclerotic lesions, and the level of platelets, PT, PTT, INR, LDL and HbA1c were similar between patients with and without re-occlusion. Compared to patients without re-occlusion, those with re-occlusion had a higher proportion of stroke with the etiology of large artery atherosclerosis (34.8% vs 3.2%, p<0.001), and tended to have a longer time from last know well to groin puncture (498 ± 411 vs 408±328 minutes, p=0.15).

Conclusion: Large artery atherosclerotic disease was a more common stroke etiology in patients with re-occlusion during thrombectomy for ELVO. Underlying vasculopathy and plaque rupture may have precipitated the thrombotic process.

Abstract WP392: Non-English Speakers Present Faster with More Severe Strokes

Introduction: With the continued expansion of acute stroke treatment options, urban tertiary referral centers such as ours are treating an increasingly diverse patient population. As we attempted to better understand barriers to improved door to treatment times in our acute stroke code protocol, we postulated that there might be differences in severity of presentation and swiftness of acute stroke care based on English fluency.

Methods: Through a departmental quality improvement project to optimize local policy in the context of new acute stroke treatment guidelines, we compared National Institute of Health Stroke Scale (NIHSS) at presentation, time to presentation, and time to treatment of fluent English speakers to patients who were not fluent in English. We analyzed data from 667 acute stroke codes from January 2017 to March 2018 with Statistical Package for the Social Science (SPSS) using two-tailed t-tests.

Results: In-Hospital stroke codes included 415 English speakers and 97 non-English speakers, while Outside Hospital (OSH) transfers comprised 92 English speakers and 35 non-English speakers. Non-English-speaking patients had higher average NIHSS scores at time of acute stroke presentation (11 vs 8 (p=0.013) in-hospital and 17 vs 13(p = 0.007) OSH transfer). Last known well (LKW) to stroke code time upon arrival to our center was significantly shorter in non-English speakers compared to English speakers coming from an OSH (315 minutes vs 515 minutes, p = 0.016), but there were no statistically significant differences between language groups for in-hospital codes’ LKW to stroke code times. There were no statistically significant differences in acute treatment times, but in the OSH transfer group, average LKW to groin puncture was 349 minutes for non-English speakers compared to 545 minutes for English speakers (p=0.085).

Conclusions: This data suggests that at our center, non-English speakers present with more severe strokes and present more quickly. Increased stroke severity may partially explain an observed trend towards faster times from LKW to thrombectomy for non-English speakers transferred from an OSH.

The Frequency and Severity of Magnetic Resonance Imaging Abnormalities in Infants with Mild Neonatal Encephalopathy

OBJECTIVE

To assess and contrast the incidence and severity of abnormalities on cerebral magnetic resonance imaging (MRI) between infants with mild, moderate, and severe neonatal encephalopathy who received therapeutic hypothermia.

STUDY DESIGN

This retrospective cohort studied infants with mild, moderate, and severe neonatal encephalopathy who received therapeutic hypothermia at a single tertiary neonatal intensive care unit between 2013 and 2015. Two neuroradiologists masked to the clinical condition evaluated brain MRIs for cerebral injury after therapeutic hypothermia using the Barkovich classification system. Additional abnormalities not included in this classification system were also noted. The rate, pattern, and severity of abnormalities/injury were compared across the grades of neonatal encephalopathy.

RESULTS

Eighty-nine infants received therapeutic hypothermia and met study criteria, 48 with mild neonatal encephalopathy, 35 with moderate neonatal encephalopathy, and 6 with severe neonatal encephalopathy. Forty-eight infants (54%) had an abnormality on MRI. There was no difference in the rate of overall MRI abnormalities by grade of neonatal encephalopathy (mild neonatal encephalopathy 54%, moderate neonatal encephalopathy 54%, and severe neonatal encephalopathy 50%; P= .89). Basal ganglia/thalamic injury was more common in those with severe neonatal encephalopathy (mild neonatal encephalopathy 4%, moderate neonatal encephalopathy 9%, severe neonatal encephalopathy 34%; P = .03). In contrast, watershed injury did not differ between neonatal encephalopathy grades (mild neonatal encephalopathy 36%, moderate neonatal encephalopathy 32%, severe neonatal encephalopathy 50%; P = .3).

CONCLUSION

Mild neonatal encephalopathy is commonly associated with MRI abnormalities after therapeutic hypothermia. The grade of neonatal encephalopathy during the first hours of life may not discriminate adequately between infants with and without cerebral injury noted on MRI after therapeutic hypothermia.

Fast microwave-assisted conjugation of magnetic nanoparticles with carboxylates of biological interest

A new technique of surface modification of nanoparticles (Fe₃O₄-NP) with carboxylates of biological interest has been developed with a microwave-assisted heating method.

Antifolate-modified iron oxide nanoparticles for targeted cancer therapy: inclusion vs. covalent union

In this work four different iron oxide nanoparticles for the delivery of antitumoral drugs into cancer cells were synthesized and characterized.

Prevalence of autistic spectrum disorder in children attending mainstream schools in a Welsh education authority

All mainstream primary schools in Cardiff were invited in July 1998 to participate in a prevalence survey of autistic spectrum disorder. Teachers of each class filled in a questionnaire based on ICD-10 criteria for autistic disorders. The Autism Spectrum Screening Questionnaire (ASSQ) was completed on children identified with problems identified by the questionnaire. A total of 11692 children born between 1 September 1986 and 31 August 1990 were screened: 234 (2%) children were identified as requiring an ASSQ; 151 of 234 (65%) ASSQs were returned. Of the 151, 60 children (52 male, 8 female; 40%) scored 22 or more. Their notes and the involved professionals were consulted. Thirty-five children, unknown to specialist services or with complex features, required additional assessment. Seventeen children (all male) were found to be on the autistic spectrum. When the overall rubric was disentangled we found a diverse population of affected children including a handful who did not fit easily into ICD-10 classification. Correcting for incomplete ascertainment we found a minimum prevalence of 20.2 out of every 10 000 (SE = 4.5) for autistic spectrum disorder in this population.

Enhancing patient safety through teamwork training

The effective reduction of medical errors depends on an environment of safety for patients in both clinically-based and systems-oriented arenas. Formal teamwork training is proposed as a systems approach that will achieve these ends. In a study conducted by Dynamics Research Corporation, weaknesses and error patterns in Emergency Department teamwork were assessed, and a prospective evaluation of a formal teamwork training intervention was conducted. Improvements were obtained in five key teamwork measures, and most importantly, clinical errors were significantly reduced.