Search

Supplemental Digital Content is available in the text.

Supplemental Digital Content is available in the text.

Introduction:Application of machine learning (ML) algorithms has shown promising results in estimating ischemic core volumes using routine non-contrast CT (NCCT). We aimed to assess the performance of the e-Stroke Suite software (Brainomix, Oxford, United Kingdom) in assessing ischemic core volumes on NCCT compared to CTP in patients with acute ischemic stroke.Methods:In this retrospective study, consecutive patients with anterior circulation large vessel occlusions who underwent pretreatment NCCT and CTP and posttreatment MRI were included. Ischemic core volumes were automatically calculated on NCCTs using e-Stroke Suite (Brainomix) which uses a combination of traditional 3D graphics and ML classification techniques to identify ischemic core voxels. Estimated ischemic core volumes were also automatically calculated from CTP using Olea Sphere (Olea Medical SAS, SP23) using a combination of rCBF<25% and differential Time-to-peak (dTTP)>5 sec. Estimated core volumes were compared against the final infarct volume on posttreatment MRI in patients who achieved successful reperfusion (mTICI ≥2b).Results:83 patients [52 female; age (mean ± SD): 73.1 ±15.3] were included. The estimated ischemic core volumes (mean ± SD) were 18.9 ± 13.5 mL on NCCT and 17.5 ± 16.5 mL on CTP, not significantly different (p=0.54) and demonstrated significant correlation (r=0.51, p<0.001) (Figure 1). Among patients with successful recanalization (n=49), there was no significant difference in estimated ischemic core volume between NCCT vs. CTP (p=0.80) and NCCT vs. MRI (p=0.38). There was significant correlation between estimated ischemic core volume on NCCT vs. CTP (r=0.75, p<0.001) and vs. final MRI infarct volume (r=0.75, p<0.001).Conclusions:Results show estimated ischemic core volumes obtained automatically by ML-based approach (Brainomix) on NCCT correlates well with ischemic core volumes on acute CTP and with post-treatment MR infarct volume.

Background:Few data exists on acute stroke treatment in patients with pre-existing disability (PD) since they are usually excluded from clinical trials.Methods:A pre-specified subgroup analysis of tPA-eligible patients with PD enrolled in a prospective multicenter trial of Mobile Stroke Units (MSUs) vs standard management by emergency medical services (EMS). All patients had baseline mRS scores. Co-primary outcomes were mean utility-weighted modified Rankin Scale score (uw-mRS) and return to baseline mRS at 90 days. Linear and logistic regression models compared outcomes in patients with vs without PD, and patients with PD treated by MSU vs EMS. Time metrics, safety, quality of life, and health-care utilization were also compared.Results:Of 1047 patients, 254 had baseline mRS>=2 (159 MSU, 95 EMS; 31% mRS 2, 52% mRS 3, 17% mRS 4). Compared to patients without disability, patients with PD were older, had higher NIHSS, more comorbidities, less often lived at home, were treated slower, and had less thrombectomy. Patients with PD had worse 90-day uw-mRS (0.39 vs 0.80), higher mortality, more health-care utilization and worse quality of life than patients without PD. However, rates of symptomatic intracranial hemorrhage and final diagnoses of stroke mimics were similar between groups, and 52% of patients with PD returned to their baseline mRS. Patients with PD treated within the first hour had better 90-day uw-mRS than those treated later (0.48 vs 0.36, p=0.01). Comparing patients with PD treated by MSU vs EMS, time from last-known-well to tPA bolus was shorter (82 vs 111 min), and 24% vs 0% were treated in the first hour. Among patients with PD, MSU patients had non-significantly better 90-day uw-mRS (0.41 vs 0.35, p=0.09) and higher rate of returning to baseline mRS (56% vs 44%, p=0.09) than EMS patients. There was no interaction between either time to treatment (p=0.24) or MSU vs EMS group assignment (p= 0.42), 90-day uw-mRS, and PD vs no disability status.Conclusion:Although outcomes after stroke are less favorable in patients with vs without PD, in a large, controlled trial, we found no interaction between baseline disability and the benefit of MSU treatment. Our data support the earliest treatment of acute stroke patients regardless of premorbid functional status.

Introduction:Incidentally discovered cerebral aneurysms are increasingly common as patients are more frequently imaged. To aid in this management, we developed an aneurysm alert system. Here we describe the effectiveness and outcomes of our Incidental Aneurysm Alert System (IAAS).Methods:IAAS received MRA and CTA reports from our Radiology department. Reports were parsed using natural language processing to identify ‘aneurysm’, automatically generating alerts for the interventional neuroradiologists. Background demographics, referral patterns, risk factors and management were then assessed.Results:From March to December 2020, 145 consecutive reports were reviewed. A 87% cerebral aneurysm detection accuracy rate resulted after excluding duplicates and non-vascular lesions, resulting in 117 unique cases. Median age was 65 and 65% were female. Most frequent races were 53% non-Hispanic White, 19% other, 9% Asian, 6% Black; 26% were of Hispanic ethnicity. The most common indication was acute stroke (29%). Of the detected aneurysms, 49% resulted in consultation with an interventionalist. Neurology was the most common referring specialty (37%). Of those referred, 49% underwent diagnostic and/or therapeutic angiography. Sixty eight percent who underwent cerebral angiography were intervened upon immediately or within 2 years of discovery. Seven percent were ruptured on discovery. Aneurysms were most frequently treated with flow diversion (37%), coiling (37%), and clipping (16%).Mean PHASES score of referred patients was 4.3, conferring 0.9-1.3% 5-year rupture risk. Asians and Hispanics had higher PHASES scores on presentation of 6.1 (1.7% 5-year rupture risk) and 5.2 (1.3% 5-year rupture risk) respectively, compared to Non-Hispanic Caucasians of 3.8 (0.9% 5-year rupture risk). For Hispanics, mean age was 55 and mean aneurysm size 9.8 mm as compared to 66 and 5.6 mm in non-Hispanic Caucasians. There were no significant differences in aneurysm risk factors.Conclusions:IAAS is an effective alerting system. Hispanics were younger with larger aneurysms on detection. IAAS may have potential value in connecting general physicians with cerebrovascular specialists, improving the management of incidentally discovered cerebral aneurysms.

Introduction:With successful reperfusion (SR, mTICI 2b-3) now being achieved in the great preponderance of patients undergoing endovascular thrombectomy (EVT), prevention of blood-brain barrier disruption and reperfusion injury is an emerging therapeutic target. For trials of agents to reduce BBB injury, the hyperintense acute reperfusion marker (HARM) sign is a potentially useful physiologic biomarker. However, past studies of HARM have generally failed to disaggregate non-EVT patients, EVT patients without SR, and EVT patients with SR.Methods:In a prospectively maintained database, we analyzed consecutive patients with SR (mTICI 2b-3) after EVT for anterior circulation large vessel occlusion undergoing post-gadolinium MRI scans at 3-6h and 24h after thrombectomy.Results:Among 48 SR patients meeting study entry criteria, the HARM sign was present in 65%. Patients with HARM sign, compared to those without, did not differ in age or NIHSS, but were more often female (54% vs 10%), more often had history of hypertension (65% vs 47%), and had higher initial SBP (156 vs 144). Patients with HARM sign more often received IV TPA (39% vs 29%), had longer time from onset to achievement of SR (median 352 vs 264 mins), underwent more passes (2.5 vs 1.9), and less often had complete (mTICI 3) reperfusion (13% vs 41%). With regard to outcomes, HARM patients more often had radiologic hemorrhage (75% vs 24%), less often were ambulatory at discharge (23% vs 59%), had less functional independence (mRS 0-2) at 90d (33% vs 59%), and had higher in-hospital mortality (16% vs 0%).Conclusion:The HARM sign is present in two-thirds of EVT patients with successful reperfusion; is associated with higher blood pressure, IV lytic therapy, longer time to reperfusion, more procedure manipulations, and less than complete macro-reperfusion; and is strongly associated with hemorrhagic transformation and worse clinical outcomes. The HARM sign is a promising biomarker for use in trials of treatments to avert reperfusion injury.

Introduction:Middle meningeal artery (MMA) embolization is an therapy utilized in the management of subdural hematomas (SDH). Based on promising preliminary data, several clinical trials are underway to evaluate the efficacy of this endovascular approach in patients with chronic subdural hematomas. However, consensus for the efficacy of MMA embolization has not been well established in acute settings or among patients with major co-morbidities.Methods:Patient data were gathered from consecutive cases performed at UCLA between 05/02/2018 and 08/26/2022. Retrospective chart review was performed to determine inpatient/outpatient status, mortality, co-morbidities, and time-to-death. Primary statistical analyses were performed to determine the proportion of patients.Results:Among the 111 patients meeting study entry criteria, 44 (39.6%) had acute, inpatient MMA procedures performed and 66 (40.4%) had elective procedures in the setting of advanced or terminal diseases (e.g. malignancy, cirrhosis). After follow-up of median 31.9 months, mean 17.4 months years, 86 (77.5%) of patients were still living and 25 (22.5%) were deceased. The age for both deceased and living patients was the same, 71±13 vs 71±16.1 years old. Mortality during follow-up was more common among patients undergoing MMA as an inpatient (47.8% vs 6.1%). Among the 25 deceased patients, mortality occurred within 1 year in 64% and beyond 1 year in 36%. Co-morbidity frequencies among deceased compared with surviving patients were: 40% vs 22%; solid tumor cancer in 28% vs 14%; cirrhosis in 32% vs 6%; and hematologic malignancy in 4% vs 4%. Among those deceased, 14 of 25 (56%) were diagnosed with a major co-morbidity (hematologic condition, cancer, or liver cirrhosis) at the time of the procedure. Among those living, 19 of 86 (22.1%) were diagnosed with a major co-morbidity (hematologic condition, cancer, or liver cirrhosis) at the time of the procedure.Conclusion:Patients with SDH undergoing MMA embolization on an acute inpatient basis have a high, nearly 50%, rate of mortality within the next 0.5-2 years, while patients electively treated despite major co-morbidities have a substantially higher survival rate.

Introduction:The Get with the Guidelines - Stroke (GWTG-Stroke) registry has been collecting endovascular thrombectomy (EVT) data on acute stroke interventions since 2015. The key variables associated with EVT, solely based on local site documentation, have never been independently adjudicated. We conducted a detailed analysis of single center EVT data as entered in the GWTG-Stroke registry.Methods:Consecutive EVT cases entered into both GWTG-Stroke and an independent research database at a large academic comprehensive stroke center were sampled from 2020-2022. For each case, the following EMR and PACS imaging variables related to EVT efficacy and safety outcomes were compared between GWTG-Stroke and core lab independent readings, including: site of target occlusion (STO), first-pass time (FPT), time mTICI >=2b50 first documented (reperfusion time), final mTICI score (0, 1, 2a, 2b50, 3; FTICI), presence of post-intervention hemorrhagic transformation (HT), and subtype/extent of HT.Results:The GWTG-Stroke registry EVT-imaging data variables document only 6/30 (20%) of the common data elements (CDEs) recommended by NINDS and 6/34 (18%) recommended by the FDA. Of the 80 cases sampled, 29 (36%) had discrepancies between GWTG-Stroke recorded data and independent core lab findings. In 4 cases (5%), reperfusion time was incorrect. In another 4 cases (5%), FTICI was incorrect, even when using the gross 2b50/3 categories. In 1 case (1.3%) STO was incorrect. In 2 cases (2.5%) patient data was not reported to GWTG-Stroke. In 21 cases (26%), HT was documented as not present, when in fact it was. Of those, 3 cases (4%) were PH2, while 18 cases (23%) were IPH of PH1 or less, SAH or SDH.Conclusions:Detailed analysis of the GWTG-Stroke registry on EVT for acute ischemic stroke reveal major discrepancies in numerous variables. In addition, the majority of variables recommended by NINDS and FDA for routine collection in thrombectomy procedures are not captured in GWTG-Stroke. Even the minority of recommended thrombectomy CDEs currently captured in GWTG-Stroke further contain subject level discrepancies in imaging and angiography outcomes when centrally adjudicated.

Introduction:While the goal of IV tissue plasminogen activator (TPA) is to prevent infarction, few data exist on averted stroke.Methods:Secondary analysis of a multicenter trial from 2014-2020 comparing outcomes between patients treated for stroke by mobile stroke unit (MSU) vs standard care (SC). The analytical cohort were patients with suspected stroke treated with IV TPA. The primary outcome was a time-defined averted stroke diagnosis, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours. The secondary outcome was a tissue-defined averted stroke diagnosis, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours and no acute infarction/hemorrhage on imaging. We used multivariable logistic regression to evaluate associations between study exposures (demographics, comorbidities, stroke characteristics) and outcomes.Results:Among 1009 patients with a median last known well-to-TPA time of 87 minutes, 276 patients (27%) had a time-defined averted stroke (31% MSU, 21% SC) and 159 patients (16%) had a tissue-defined averted stroke (18% MSU, 11% SC). Factors independently associated with time-defined averted stroke were younger age (OR, 0.98; 95% CI, 0.96-0.99), female sex (0R, 0.51; 95% CI, 0.36-0.74), hyperlipidemia (OR, 1.81, 95% CI, 1.24-2.64), normal premorbid function (0R, 2.22; 95% CI, 1.37-3.67), lower glucose (OR, 0.996; 95% CI, 0.993-0.999), lower MAP (OR, 0.991; 95% CI, 0.983-0.998), MSU care (OR, 1.77; 95% CI, 1.21-2.62), lower NIH stroke scale (OR, 0.89; 95% CI, 0.86-0.93), and no large vessel occlusion (LVO) (OR, 0.52; 95% CI, 0.32-0.83). For tissue-based averted stroke, younger age, female sex, hyperlipidemia, lower MAP, MSU treatment, lower NIH stroke scale, and no LVO were significantly associated.Conclusion:In a modern acute stroke trial, one-in-four patients treated with TPA for stroke recovered within 24 hours and one-in-six had no demonstrable brain injury on imaging. Younger age, female sex, hyperlipidemia, lower MAP, MSU care, lower stroke severity, and no LVO may increase the odds of averting stroke.

Background:Stroke education of emergency medical service (EMS) personnel improves stroke recognition, prenotification, and thrombolytic delivery. Prehospital identification of large vessel occlusion (LVO) stroke may facilitate the creation of a regional bypass protocol and improvement of intrahospital and interhospital workflows. However, the current status of EMS personnel’s knowledge of LVO, their stroke severity assessment training, and preferences in educational methods have not been studied. We conducted an EMS survey across the United States.Methods:The Society of Vascular and Interventional Neurology (SVIN) in collaboration with EMS-World created an online questionnaire distributed to all subscribers of EMS-World involved in pre-hospital work. It included 12 multiple-choice questions to test participants on LVO knowledge, stroke center certification levels, prior LVO education, and preferences on educational content delivery.Results:The survey email was opened by 1830 subscribers out of whom 1107 (60%) completed the survey across 50 states in the United States. Respondents identified themselves as paramedics/EMTs (91.4%), ground critical care (5.7%) and flight crew (2.9%). The number of stroke patients that survey participants transported in the past year was <10 for 618 (55.8%), 10 to 25 for 332 (30%), and >25 (14.2%). Two hundred eighty-five (25.8%) participants answered both LVO knowledge questions correctly and 379 (34.2%) answered one correctly. Only 128 (11.6%) correctly identified all types of centers with thrombectomy capability. Although 877 (79.2%) were familiar with at least one stroke severity scale, 376 (34%) denied receiving training to perform them. Five sixty-seven (51.2%) respondents preferred in-person training for LVO training and 429 (38.8%) an online training program. About half of all respondents (535,48%) picked 'lack of standardized LVO training' as the greatest hurdle to pre-hospital LVO management.Conclusion:EMS providers in the United States reported inadequate LVO training and demonstrated gaps in knowledge of LVO, stroke severity scales, and stroke center levels. Systematic efforts to enhance and standardize the educational content and delivery of LVO education are urgently needed.

Introduction:Transition from evidence to practice is the next challenge for Mobile Stroke Units (MSUs) now that two controlled studies have shown improved outcomes (BEST-MSU and B_PROUD). This requires successful integration into EMS systems. We sought to utilize geospatial mapping to identify the most efficient number and positioning of MSUs in Los Angeles (LA) County to maximize patient access.Methods:LA County has one of the largest EMS systems in the US, comprising 88 cities, more than 4000 sq miles, and a population of 10.2 million. Using ESRI/ArcGIS software, we performed geospatial mapping of all 911 calls resulting in a final diagnosis stroke from July 2016 - June 2019, converting street addresses to latitude/longitude. Regional heatmaps of stroke call volume were generated for day/evening (7 am-10 pm) vs nighttime (10 pm-7 am) and ischemic vs hemorrhagic stroke, superimposed upon available stroke centers and neighborhood sociodemographic factors. Based on pilot experience, each MSU was projected to be able to service a 10-mile radius.Results:Among 10,818 EMS responses for acute cerebrovascular disease during the 3-year study period, calls occurred during day/evening in 84.5% and nighttime in 15.5%. Stroke type was ischemic in 78.8% and hemorrhagic in 21.2%. Heat maps revealed multifocal geographic hotspots, with most active locations somewhat different for day/evening vs night and ischemic vs hemorrhagic. The spatial analysis algorithm determined that optimal placement of 5 MSUs in highest incidence areas would provide coverage for 87.0% of county stroke events. Positioning of 2 additional units in geographically isolated perimeter areas increased coverage to 91.9% of stroke events (Figure).Conclusions:Geospatial modeling can delineate the most efficient positioning of MSU resources within regionalized EMS systems of stroke care. Optimal position varies with time of day and with prioritization of coverage for ischemic vs hemorrhagic stroke.

Introduction:Mobile Stroke Units (MSUs) improve clinical outcome in patients treated with tPA compared to standard management by Emergency Medical Services (EMS), but the impact of MSUs on outcomes in patients with large vessel occlusions (LVOs) having endovascular thrombectomy (EVT) has yet to be determined.Methods:A pre-specified substudy of tPA-eligible stroke patients with LVOs on CT and/or CTA who were enrolled in the Benefits of Stroke Treatment Using a Mobile Stroke Unit (BEST-MSU), a prospective multicenter controlled trial comparing MSU with standard EMS management, was conducted. The primary outcome was the score on the 90-day utility-weighted modified Rankin Scale (uw-mRS). Secondary outcomes were rate of early neurologic recovery (30% improvement in NIHSS score) at 24 hours and functional independence (mRS 0-1) at 90 days.Results:A total of 295 patients were included, 169 in the MSU group and 126 in the EMS group. Baseline characteristics were comparable between the groups, with the exception of baseline NIHSS (MSU median 19.0 [IQR 13.0, 23.0] vs EMS 16.0 [11.0, 20.0], p=0.003). 92% MSU vs 87% EMS LVO patients received tPA, and 78% vs 85% went on to have EVT. MSU LVO patients had faster tPA bolus from symptom onset (65.0 min [50.5, 92.0] vs 96.0 [79.3, 130.0], p<0.001), however the two groups had similar onset to groin puncture (169.0 min [133.8, 212.3] vs 162.0 [135.3, 207.0], p=0.77). The mean (±SD) score on the uw-mRS at 90 days was 0.64±0.39 in the MSU group and 0.50±0.40 in the EMS group (mean difference 0.16, 95% CI [0.07, 0.25] after adjustment for age, baseline NIHSS, premorbid functional status, prior stroke/TIA and site; p<0.001). Early neurologic recovery (68% vs 52%; adjusted OR 1.89 95% CI [1.14,3.17]) and functional independence (Figure 1, 42% vs 29%; 2.48 [1.38,4.55]) also favored the MSU group.Conclusions:In tPA-eligible LVO stroke patients, MSU management was associated with better clinical outcomes compared with standard EMS management.

Introduction:Intracranial artery calcification (ICAC) is a common finding on CTA in patients presenting with LVO acute ischemic stroke and could potentially serve as a useful biomarker of intracranial atherosclerosis and altered intracranial vessel pliability in patients undergoing endovascular thrombectomy (EVT). However, ICAC frequency, determinants, and outcome associations have not been well delineated.Methods:In a prospectively maintained database, we analyzed consecutive patients undergoing CTA immediately prior to EVT from Mar 2016 - Aug 2020. Extent of ICAC in the intracranial ICA or VA proximal to the target vessel was scored using a validated grading scale (Babiarz et al, AJNR 2003: 5 levels for greatest calcific thickness and 5 levels for greatest circumferential extent). Example cases in Figure 1. Patients were stratified into low (0-2), medium (3-4), and high (5-6) ICAC groups.Results:Among 91 patients, mean age was 73, 54% female, and mean NIHSS 17. Median ICAC score was 3 [IQR 0-4]. Baseline characteristics associated with higher ICAC scores were: CAD (3.8 vs. 2.4, p= 0.02), HTN (3.1 vs. 2.1, p= 0.07), and age (r= 0.50, p < 0.001). There was a U-shaped association between ICAC score and successful reperfusion (mTICI 2b-3): 90.9%, 65.7%, and 95.0% in low, medium, and high ICAC score groups, respectively (p= 0.006). Need for rescue intervention (angioplasty/stenting, IA thrombolysis, or GpIIb/IIIa inhibitor) was higher in the high ICAC group: 5.9% vs. 5.6% vs. 28.6% (p= 0.01). Functional independence (mRS 0-2) at discharge (29.4% vs. 22.2% vs. 19.0%, p= 0.64) or 90 days (40.0% vs. 30.0% vs. 21.4%, p= 0.22) did not differ, nor did symptomatic intracranial hemorrhage (p= 0.96).Conclusions:Calcification of intracranial vessels is frequently seen on CTA in LVO patients and is associated with age and vascular risk factors. Degree of calcification has important associations with rates of successful reperfusion and need for rescue intervention during EVT.

Background and Purpose:Accurate estimation of ischemic core on baseline imaging has treatment implications in patients with acute ischemic stroke (AIS). Machine learning (ML) algorithms have shown promising results in estimating ischemic core using routine non-contrast CT (NCCT). We used a ML-trained algorithm to quantify ischemic core volume on NCCT and compared the results to concurrent diffusion MRI as the reference standard in patients with AIS.Methods:We analyzed consecutive anterior circulation AIS patients who had baseline (pretreatment) NCCT and MRI (DWI). Ischemic lesion volume was calculated on MRI-DWI using an automated software (Olea Medical SAS, La Ciotat, France). An automatic segmentation approach using a combination of traditional 3D graphics and statistical methods, and ML classification techniques (Brainomix, Oxford, United Kingdom) was used to identify ischemic core voxels on NCCT. Total ischemic core volumes on ML-NCCT and DWI-MR were quantitatively compared by Bland-Altman plots and Pearson correlation.Results:A total of 50 patients (27 female, 23 male, mean age 72.6 years) were included. Baseline imaging was performed within 173 ± 143 minutes (mean ± SD) from symptom onset. The mean time difference between MRI and NCCT was 72 min. The baseline NIHSS was 14, 8-21 (Median, IQR). Algorithm-segmented ischemic core volume detected on NCCT was median 12.7 mL, IQR 3.5-26.0 mL. Ischemic core volume on DWI MRI was median 8.8 mL, IQR 3.2-34.0 mL. ML-NCCT core volumes significantly correlated with DWI MRI core volumes, r=0.61, p<0.001. The mean difference between the ML-NCCT and DWI MRI core volumes was 12.4 mL, p=0.81. For the reperfusion treatment threshold of an ischemic core volume within 70 mL, while no patients would have been excluded using our algorithm, five patients would have been incorrectly dichotomized as having an ischemic volume of <70 mL compared to MRI.Conclusion:This ML-approach accurately quantifies ischemic core volume on NCCT compared to the reference standard of diffusion MRI in patients with AIS.

Background and Purpose:Acute leptomeningeal collateral flow is vital to maintain blood perfusion to penumbral tissue in acute ischemic stroke due to large vessel occlusion (LVO). However, the degree of this collateral flow differs among patients. Patient premorbid factors as well as factors caused by the mechanisms of stroke are expected to be associated with this collateral flow. We aimed to investigate the clinical determinants of acute leptomeningeal collateral flow in embolic LVO.Methods:Among consecutive stroke patients caused by acute embolic anterior circulation LVO, we retrospectively reviewed 108 patients who underwent evaluation of acute leptomeningeal collateral status (CS) on pretreatment CTA admitted from January 2015 to December 2019. Both premorbid information including cerebrovascular risk factors and leukoaraiosis evaluated by the total white matter (WM) Fazekas score on MRI, which was calculated as periventricular plus deep WM scores, and stroke related information including stroke subtypes, severity, time course, and occlusive thrombus characteristics were collected. Among thrombus characteristics, thrombus length was measured by tracing the filling defect of contrast on CTA. The clinical determinants of good leptomeningeal CS (> 50% collateral filling of the occluded territory) were analyzed.Results:CS was good in 67 patients (62%). On multivariate logistic regression analysis, cardioembolic stroke subtype was negatively related (OR, 0.170; 95% CI, 0.022-0.868), and mild leukoaraiosis (total WM Fazekas scores of 0-2) was positively related (OR, 9.57; 95% CI, 2.49-47.75) to good CS. On subgroup analysis limited to 82 patients with cardioembolic stroke, shorter thrombus length (OR, 0.913 per mm increase; 95% CI, 0.819-0.999) as well as mild leukoaraiosis (OR, 5.79; 95% CI, 1.40-29.61) were independently related to good CS.Conclusions:Premorbid leukoaraiosis and cardioembolic etiology are determinants of acute leptomeningeal collateral flow in embolic LVO. In addition, thrombus length is also a determinant of collateral flow in cardioembolic LVO. These findings indicate that a combination of chronic cerebrovascular damage and acute embolic mechanisms could determine the degree of leptomeningeal collateral flow.

Background and Purpose:In acute ischemic stroke (AIS), perfusion imaging, while not directly visualizing collateral vessels, can provide important insight into collateral robustness, indexed by perfusion lesion volume and by perfusion lesion heterogeneity. Two proposed perfusion lesion heterogeneity measures indexing collateral status are the Perfusion Collateral Index (PCI) and Hypoperfusion Intensity Ratio (HIR), but their accuracy compared with direct collateral assessment on DSA has been incompletely characterized.Methods:Consecutive AIS patients with anterior circulation large vessel occlusion who underwent pre-endovascular thrombectomy MRI perfusion imaging were included. MRI measures analyzed were: 1) Perfusion Collateral Index (PCI)- the volume of moderately hypoperfused tissue (arterial tissue delay time between 2 and 6 seconds: ATD2-6sec) multiplied by its corresponding relative cerebral blood volume using Olea software; 2) Hypoperfusion Intensity Ratio (HIR) ratio of moderate TMax >6 s lesion volume versus severe Tmax >10 s lesion volume with the RAPID software program. DSA collateral scores were evaluated by ASITN grading and dichotomized to inadequate (ASTIN <2) vs. adequate (ASTIN ≥3).Results:Among 48 patients meeting entry criteria, age (mean ± SD) was 70 (± 15.2), 54% were female, and NIHSS (median, IQR) was 15 (10-19). For HIR, there was no significant difference in score values in patients with adequate vs inadequate collaterals: 0.35 ± 0.20 vs 0.39 ± 0.25, p=0.68. ROC analysis using previously described cut-off of 0.4 resulted in an AUC of 0.52 and sensitivity/specificity of 71% / 33%. For PCI, score values were significantly higher in patients with adequate vs inadequate collaterals, 117 ± 61 vs. 57 ± 41, p=0.002. ROC analysis using previously described cut-off of 62 resulted in an AUC of 0.8 and sensitivity/specificity of 84% / 78%.Conclusion:Collateral status can be accurately assessed on perfusion MRI with the Perfusion Collateral Index, which outperformed the Hypoperfusion Intensity Ratio. MRI-PCI is an informative imaging biomarker of collateral status in patients with AIS.

Introduction:Most clinical research stopped during COVID due to possible impact on data quality and personnel safety. We aimed to assess the impact of COVID on study conduct at sites that continued to enroll patients during the pandemic.Methods:BEST-MSU is an ongoing study of Mobile Stroke Units (MSU) vs standard management of tPA eligible acute stroke patients in the pre-hospital setting. MSU personnel include a vascular neurologist via telemedicine, and a nurse, CT tech, and medics on board using appropriate PPE. During COVID, consent, 90 d mRS and EQ5D could be obtained by phone instead of in person, otherwise management was the same. We compared patient demographics, study metrics, and infection of study personnel during intra- vs pre-COVID eras.Results:Four of 6 BEST-MSU sites continued to enroll during COVID. There was no difference in intra- (n= 41) vs pre- (n= 763) COVID enrolled tPA eligible patients’ age, sex, race (45% vs 41% Black), ethnicity (23% vs 19% Hispanic), or NIHSS (12 vs 12). MSU alert frequency did not change, but percent of screened patients enrolled and treated with tPA declined to 12% from 23% (p<.001); enrollment correlated with local stay at home and reopening (fig). There was no difference in alert to MSU arrival or arrival to tPA times, but on-scene time was 2 min longer (p=.04). There was no difference in ED door to CT, tPA, or EVT times, hospital LOS, discharge disposition, or 90d mRS or EQ5D accuracy. One MSU nurse tested positive but did not require medical care.Conclusion:Clinical research in the pre-hospital setting can be carried out accurately and safely during a pandemic. Study enrollment and tPA treatment rates declined, but otherwise there was no difference in patient demographics, deterioration of study processes, or serious infection of study staff.

Introduction:Aneurysmal subarachnoid hemorrhage (aSAH) is a rare event associated with significant pregnancy-associated maternal and neonatal morbidity and mortality. With advances in neurosurgical and neurocritical care, there have been significant improvement in survival and clinical outcome of patients with aSAH. We aimed to investigate the treatment utilizations and outcomes of aSAH in pregnancy.Methods:Retrospective analysis using the Nationwide Inpatient Sample identified women 18-45 years-old hospitalized between 2010-2015. We identified pregnancy state, subarachnoid hemorrhage, and aneurysm treatments in this cohort. The mode of aneurysm treatment, mortality, and discharge destination was compared in pregnant versus non-pregnant cohorts.Results:9,667 aSAH with treatment were identified, of which 341 were associated with pregnancy. Mortality in the pregnancy and non-pregnancy were not different (7.37% vs 7.39%, p=0.97). However, pregnancy-related admissions were more likely to be discharged to home or short-term facility (71.9% vs 63.8%, p=0.002). Endovascular treatment for aSAH was more prevalent in pregnancy vs non-pregnancy (73% vs 66.3%, p=0.004). During the study epoch, there was a significant increase in endovascular treatment in pregnancy related aSAH (p<0.001). Surgical clipping was associated with higher mortality in pregnancy compared to non-pregnancy (15.9% vs 6.8%, p<0.001). There was no difference in mortality following endovascular treatment in pregnancy vs non-pregnancy (6.1% vs 7.8%, p=0.26). Favorable discharge outcome was significantly higher for pregnancy vs non-pregnancy with endovascular treatment (75.8% vs 63.9%, p<0.001), whereas no significant difference was observed in rate of favorable outcome for pregnancy and non-pregnancy with surgical clipping (57.9% vs 61.2%, p=0.29).Conclusions:Pregnancy does not alter mortality from aSAH. Among interventions for aSAH, surgical clipping is associated with higher mortality in pregnancy compared to non-pregnancy. However, pregnancy is associated with more favorable discharge outcomes (vs controls) and no change in mortality in this cohort. Consideration for endovascular intervention with aSAH in this cohort should be considered.