Stroke Code Patients Research Articles

Distal Medium Vessel Occlusions Can Be Accurately and Rapidly Detected Using Tmax Maps.

Distal medium vessel occlusions (DMVOs) are increasingly considered for endovascular thrombectomy but are difficult to detect on computed tomography angiography (CTA). We aimed to determine whether time-to-maximum of tissue residue function (Tmax) maps, derived from CT perfusion, can be used as a triage screening tool to accurately and rapidly identify patients with DMVOs. Consecutive code stroke patients who underwent multimodal CT were screened retrospectively. Two experienced readers evaluated all patients’ Tmax maps in consensus for presence of delay in an arterial territory (territorial Tmax delay). The diagnostic accuracy of this surrogate for identifying DMVOs was determined using receiver-operating characteristic analysis. CTA, interpreted by 2 experienced neuroradiologists with access to all imaging data, served as the reference standard. Diagnostic performance of 4 other readers with different levels of experience for identifying DMVOs on Tmax versus CTA was also assessed. These readers independently assessed patients’ Tmax maps and CTAs in 2 separate timed sessions, and areas under the receiver-operating characteristic curves were compared using the DeLong algorithm. The Wilcoxon signed-rank test was used to comparatively assess diagnostic speed. Three hundred seventy-three code stroke patients (median age, 70 years; 56% male, 70 with a DMVO) were included. Territorial Tmax delay had a sensitivity of 100% (CI95, 94.9%–100%) and specificity of 87.8% (CI95, 83.6%–91.3%) for presence of a DMVO, yielding an area under the receiver-operating characteristic curves of 0.939 (CI95, 0.920–0.957). All 4 readers achieved sensitivity >95% and specificity >84% for detecting DMVOs using Tmax maps, with diagnostic accuracy (area under the receiver-operating characteristic curves) and speed that were significantly (P<0.001) higher than on CTA. Territorial Tmax delay had perfect sensitivity and high specificity for a DMVO. Tmax maps were accurately and rapidly interpreted by even inexperienced readers, and causes of false positives are easy to recognize and dismiss. These findings encourage the use of Tmax to identify patients with DMVOs.

Comparison of automated infarct core volume measures between non-contrast computed tomography and perfusion imaging in acute stroke code patients evaluated for potential endovascular treatment

IntroductionPatients with small core infarction and salvageable penumbra are likely to benefit from endovascular treatment (EVT). As computed tomography perfusion imaging (CTP) is not always available 24/7 for patient selection, many patients are transferred to stroke centers for CTP. We compared automatically measured infarct core volume (NCCTcore) from the non-contrast computed tomography (NCCT) with ischemic core volume (CTPcore) from CTP and the outcome of EVT to clarify if NCCTcore measurement alone is sufficient to identify patients that benefit from transfer to stroke centers for EVT. Patients and methodsWe included all consecutive stroke-code patients imaged with both NCCT and CTP at Helsinki University Hospital during 9/2016–01/2018. NCCTcore and CTPcore volumes were automatically calculated from the acute NCCT images. Follow-up infarct volume (FIV) was measured from 24 h follow-up NCCT to evaluate efficacy of EVT. To study whether NCCTcore could be used to identify patients eligible to EVT, we sub-grouped patients based on NCCTcore volumes (>50 mL and ≥ 70 mL). ResultsOut of 1743 patients, baseline NCCTcore, CTPcore and follow-up NCCT was available for 288 patients. Median time from symptom onset to baseline imaging was 74 min (IQR 52–118), and time to follow-up imaging 24.15 h (22.25–26.33). Baseline NCCTcore was 20 mL (10–42), CTPcore 4 mL (0–16), and FIV 5 mL (1–49). Out of 288 patients, 23 had NCCTcore ≥ 70 mL and 26 had CTPcore ≥ 70 mL. NCCTcore and CTPcore performed similarly well in predicting large FIV (≥70 ml). ConclusionNCCTcore is a promising tool to identify patients that are not eligible to EVT due to large ischemic cores at baseline imaging.

Abstract 18: The Role of Vascular Imaging at Primary Stroke Centers in the Drip and Ship Paradigm

Background: In drip-and-ship protocols, vascular imaging at Primary Stroke Centers (PSC), although recommended, is not usually performed in many PSC, and its value is uncertain. Our aim was to evaluate the role of performing vascular imaging at PSC, comparing patients with vascular imaging at PSC (VI+) Vs. those without vascular imaging (VI-) in several outcomes. Methods: Observational, multicenter study from a prospective, government-mandated, population-based registry of ischemic stroke code patients firstly evaluated at a PSC from January-2016 to June-2020. We determined and compared rates of Mechanical Thrombectomy (MT) candidates transferred to CSC from all ischemic stroke codes at PSC, MT treated at CSC patients from all MT candidates transferred, and metrics related to drip-and-ship paradigm between VI + and VI- groups. A multivariate analysis to determine PSC related factors associated with receiving EVT at CSC was performed. Results: From 5792 ischemic stroke code patients at PSC, 3384 (58.4%) received a vascular imaging at PSC (VI+). Among all, 32.6% were transferred to CSC as MT candidates, and finally, 10.6% were treated with MT at CSC. The rate of transferred MT candidates was lower in the VI+ than VI- group (n: 783, 23.1% Vs. n: 1109, 46 %, p&lt; 0.001). Among the transferred MT candidates, MT treatment at CSC was more common in the VI+ than VI- (n: 377, 48.1% Vs: n: 239, 21.5%, p&lt;0.001). In patients transferred with baseline mild strokes (NIHSS &lt;6), the rate of MT treated patients was higher in VI+ than VI- (n: 31, 29% Vs. n: 20, 7% p&lt;0.001). Interval times as DIDO (median minutes 84 Vs. 81) and DTP time (188 Vs. 182) did not show differences between VI+ and VI-. In multivariate analysis adjusted by age, the independent factors associated to receiving MT at CSC were VI+ (OR: 2,128, CI95%:1,549-2,922, p&lt;0.001), baseline NIHSS, and RACE scale. Conclusion: In the present study, performing vascular imaging at PSC diminishes unnecessary transfers to CSC and is associated with a higher probability of receiving MT at CSC in transferred patients. In mild strokes, performing a vascular imaging at PSC increases the probability of receiving MT at CSC. Metrics related to drip-and-ship model were not affected by performing a vascular imaging at PSC.

Abstract P845: Impact of T-Pa Pre-Pull Criteria in Collaboration With Telestroke Nurse

Background and Purpose: “Target: Stroke Phase III” aims to improve stroke outcomes through the reduction of door-to-needle (DTN) times within 60 minutes in 85% of cases. After a recent data review, DTN times exceeded 60 minutes in the majority of alteplase (t-PA) cases at facilities monitored by our Telestroke (TS) program. With our TS nurses (RNs) being a unique resource to quickly assess Code Stroke patients and identify eligibility for t-PA we were able to implement an ‘Alteplase Pre-Pull’ protocol to instruct the bedside staff to pull t-PA and have it at bedside prior to the teleneurologist’s assessment. Methods: Data was retrospectively collected from July-December 2019 (pre-mixed) and compared to data from January-June 2020 (pre-pulled). TS RNs were educated on pre-pull protocol titled “Less Than 3, Pull Me”. For patients presenting within three hours of symptom onset, TS RN would recommend bedside staff to pull t-PA and have at bedside: this would shave valuable minutes off DTN times if found to be t-PA eligible. TS RN would continue to assess for exclusions. Results: Significant improvements in DTN times due to pre-pulling t-PA. Average DTN time (total-241 patients July-December 2019) improved from 57 minutes to 51 minutes (231 patients Jan-June 2020). Average DTN for pre-pulled patients decreased by 3 minutes from 51 to 48 minutes. Average door to activation decreased from 12 to 7 minutes. Conclusion: Pre-pulling t-PA using the “Less Than 3, Pull Me” protocol significantly reduced DTN times by 6 minutes from 57 to 51 minutes. Activation-to-needle decreased by 1 minute from 46 to 45 minutes indicating that early activation leads to faster DTN times. Early recognition of symptoms by bedside staff is essential to decreasing DTN times. The second half of this study took place amid the COVID-19 pandemic impacting bedside staff due to limited resources. In summary, pre-pulling t-PA has allowed us to shave 6 life-saving minutes off DTN times equating to 11.4 million neurons (Puig, 2018).

Patterns of Admission and Outcomes for Patients with Intracranial Hemorrhage in Catalonia, Spain

Limited information is available about the hospital types to which patients with intracerebral hemorrhage (ICH) are admitted and treated. This could be important because some effective therapeutic measures can only be administered at comprehensive stroke centers (CSCs). Using the Acute Hospitals Discharge database, which provides population-based information, we identified ICH patients admitted to 7 CSCs and 53 non-CSCs (from January 2015 to December 2016) in Catalonia. CSCs were defined as centers with an emergency department ready to assess and treat code stroke patients around the clock, 24-hour availability of neurology, neurosurgery, and neuroradiology services, and admission to the stroke unit and/or intensive care unit. The database provided the demographics, admitting hospital, and interhospital transfers. Vital status was retrieved from the Central Registry of the Catalan Public Health Insurance. A total of 3339 ICH patients were identified (mean age, 72.2 ± 14.6 years; 56.8% men). Of the 3339 patients, 45.7% were admitted to a CSC and 54.3% to a non-CSC. Transfer from a non-CSC to a CSC occurred for 1.97% of the patients. In-hospital mortality was similar between the CSCs and non-CSCs (30.2% vs. 27.5%; P= 0.09). The long-term mortality was also comparable between the CSC and non-CSC groups (45.4% vs. 47%; P= 0.34). Despite a considerable proportion of ICH patients remaining at a non-CSC for their entire hospitalization, the short- and long-term mortality were comparable between the 2 hospital types. More studies are required to determine whether outcomes other than mortality might be related to the admitting hospital type and whether the routing protocols for ICH patients should be modified.

Stroke Code Presentations, Interventions, and Outcomes Before and During the COVID-19 Pandemic.

Anecdotal reports suggest fewer patients with stroke symptoms are presenting to hospitals during the coronavirus disease 2019 (COVID-19) pandemic. We quantify trends in stroke code calls and treatments at 3 Connecticut hospitals during the local emergence of COVID-19 and examine patient characteristics and stroke process measures at a Comprehensive Stroke Center (CSC) before and during the pandemic. Stroke code activity was analyzed from January 1 to April 28, 2020, and corresponding dates in 2019. Piecewise linear regression and spline models identified when stroke codes in 2020 began to decline and when they fell below 2019 levels. Patient-level data were analyzed in February versus March and April 2020 at the CSC to identify differences in patient characteristics during the pandemic. A total of 822 stroke codes were activated at 3 hospitals from January 1 to April 28, 2020. The number of stroke codes/wk decreased by 12.8/wk from February 18 to March 16 (P=0.0360) with nadir of 39.6% of expected stroke codes called from March 10 to 16 (30% decrease in total stroke codes during the pandemic weeks in 2020 versus 2019). There was no commensurate increase in within-network telestroke utilization. Compared with before the pandemic (n=167), pandemic-epoch stroke code patients at the CSC (n=211) were more likely to have histories of hypertension, dyslipidemia, coronary artery disease, and substance abuse; no or public health insurance; lower median household income; and to live in the CSC city (P<0.05). There was no difference in age, sex, race/ethnicity, stroke severity, time to presentation, door-to-needle/door-to-reperfusion times, or discharge modified Rankin Scale. Hospital presentation for stroke-like symptoms decreased during the COVID-19 pandemic, without differences in stroke severity or early outcomes. Individuals living outside of the CSC city were less likely to present for stroke codes at the CSC during the pandemic. Public health initiatives to increase awareness of presenting for non-COVID-19 medical emergencies such as stroke during the pandemic are critical.

Code Stroke Patient Referral by Emergency Medical Services During the Public COVID-19 Pandemic Lockdown

BackgroundThe COVID-19 pandemic caused public lockdowns around the world. We analyzed if the public lockdown altered the referral pattern of Code Stroke patients by Emergency Medical Services (EMS) to our Comprehensive Stroke Center. MethodsRetrospective single-center study at a Bavarian Comprehensive Stroke Center. Patients who were directly referred to our stroke unit by EMS between the 1st of January 2020 and the 19th of April 2020 were identified and number of referrals, clinical characteristics and treatment strategies were analyzed during the public lockdown and before. The public lockdown started on 21st of March and ended on 19th April 2020. ResultsIn total 241 patients were referred to our center during the study period, i.e. 171 before and 70 during the lockdown. The absolute daily number of Code Stroke referrals and the portion of patients with stroke mimics remained stable. The portion of female stroke patients decreased (55% to 33%; p = 0.03), and stroke severity as measured by the National Institutes of Health Stroke Scale (median 3 (IQR 0-7) versus 6 (IQR 1-15.5) points; p = 0.04) increased during the lockdown. There was no difference of daily numbers of patients receiving thrombolysis and thrombectomy. ConclusionsReferral of Code Stroke patients by EMS could be maintained sufficiently despite the COVID-19 pandemic lockdown. However, patients’ health care utilization of the EMS may have changed within the public lockdown. EMS remains a useful tool for Code Stroke patient referral during lockdowns, but public education about stroke is required prior to further lockdowns.

Universal laboratory testing for SARS-CoV-2 in hyperacute stroke during the COVID-19 pandemic

ObjectiveStroke patients are thought to be at increased risk of Coronavirus Disease 2019 (COVID-19). To evaluate yield of universal laboratory testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in acute stroke patients and its impact on hyperacute stroke care. MethodsBetween weeks 14 and 18 in 2020, a protected code stroke protocol including infection control screening and laboratory testing for SARS-CoV-2 was prospectively implemented for all code stroke patients upon arrival to the emergency department. If infection control screen was positive, patients received protective hygienic measures and laboratory test results were available within four hours from testing. In patients with negative screen, laboratory results were available no later than the next working day. Door-to-imaging times of patients treated with thrombolysis or thrombectomy were compared with those of patients treated during the preceding weeks 1 to 13 in 2020. ResultsDuring the 4-weeks study period, 116 consecutive code stroke patients underwent infection control screen and laboratory testing for SARS-CoV-2. Among 5 (4.3%) patients whose infection control screen was positive, no patient was tested positive for SARS-CoV-2. All patients with negative infection control screens had negative test results. Door-to-imaging times of patients treated with thrombolysis and/or thrombectomy were not different to those treated during the preceding weeks (12 [9-15] min versus 13 [11-17] min, p = 0.24). ConclusionsUniversal laboratory testing for SARS-CoV-2 provided useful information on patients’ infection status and its implementation into a protected code stroke protocol did not adversely affect hyperacute stroke care.

Vision, Aphasia, Neglect Assessment for Large Vessel Occlusion Stroke

Background and PurposeVision, Aphasia, Neglect (VAN) is a large vessel occlusion (LVO) screening tool that was initially tested in a small study where emergency department (ED) nurses were trained to perform VAN assessment on stroke code patients. We aimed to validate the VAN assessment in a larger inpatient dataset. MethodsWe utilized a large dataset and used National Institute of Health Stroke Scale (NIHSS) performed by physicians to extrapolate VAN. VAN was compared to NIHSS greater than or equal to 6 and established prehospital LVO screening tools including Rapid Arterial Occlusion Evaluation scale (RACE), Field Assessment Stroke Triage for Emergency Destination (FAST-ED), and Cincinnati Pre-hospital Stroke Scale (CPSS). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and area under receiver operating characteristics curve was calculated to estimate the predictive value of LVO. ResultsVAN was comparable in sensitivity (79% versus 80%) and NPV (88% versus 87%) to NIHSS greater than or equal to 6. It was superior in specificity (69% versus 57%), PPV (53% versus 46%) and accuracy to NIHSS greater than or equal to 6 (72% versus 64%) with significant receiver operating curve (.74 versus .69, P = .02).VAN also had comparable area under the curve when compared to RACE, FAST-ED, and CPSS however slightly lower accuracy (69%-73%) compared to RACE (76%), FAST-ED (77%), and CPSS (75%). VAN had the highest NPV among all screening assessments (88%). ConclusionsVAN is a simple screening tool that can identify LVOs with adequate accuracy in hospital setting. Future studies need to be conducted in prehospital setting to validate its utility to detect LVOs in the field.

Fast Automatic Detection of Large Vessel Occlusions on CT Angiography.

Background and Purpose- Accurate and rapid detection of anterior circulation large vessel occlusion (LVO) is of paramount importance in patients with acute stroke due to the potentially rapid infarction of at-risk tissue and the limited therapeutic window for endovascular clot retrieval. Hence, the optimal threshold of a new, fully automated software-based approach for LVO detection was determined, and its diagnostic performance evaluated in a large cohort study. Methods- For this retrospective study, data were pooled from: 2 stroke trials, DEFUSE 2 (n=62; 07/08-09/11) and DEFUSE 3 (n=213; 05/17-05/18); a cohort of endovascular clot retrieval candidates (n=82; August 2, 2014-August 30, 2015) and normals (n=111; June 6, 2017-January 28, 2019) from a single quaternary center; and code stroke patients (n=501; January 1, 2017-December 31, 2018) from a single regional hospital. All CTAs were assessed by the automated algorithm. Consensus reads by 2 neuroradiologists served as the reference standard. ROC analysis was used to assess diagnostic performance of the algorithm for detection of (1) anterior circulation LVOs involving the intracranial internal carotid artery or M1 segment middle cerebral artery (M1-MCA); (2) anterior circulation LVOs and proximal M2 segment MCA (M2-MCA) occlusions; and (3) individual segment occlusions. Results- CTAs from 926 patients (median age 70 years, interquartile range: 58-80; 422 females) were analyzed. Three hundred ninety-five patients had an anterior circulation LVO or M2-MCA occlusion (National Institutes of Health Stroke Scale 14 [median], interquartile range: 9-19). Sensitivity and specificity were 97% and 74%, respectively, for LVO detection, and 95% and 79%, respectively, when M2 occlusions were included. On analysis by occlusion site, sensitivities were 90% (M2-MCA), 97% (M1-MCA), and 97% (intracranial internal carotid artery) with corresponding area-under-the-ROC-curves of 0.874 (M2), 0.962 (M1), and 0.997 (intracranial internal carotid artery). Conclusions- Intracranial anterior circulation LVOs and proximal M2 occlusions can be rapidly and reliably detected by an automated detection tool, which may facilitate intra- and inter-instutional workflows and emergent imaging triage in the care of patients with stroke.

PREMISE: Posterior Circulation Results Comparing Embolectomy to Medical Intervention in Stroke Emergencies.

BackgroundIntravenous (IV) tissue plasminogen activator (rt-PA) is a proven therapy for stroke in the acute treatment window. Recent published data has shown efficacy for embolectomy for acute ischemic strokes within up to six, 16 and 24 hours in the anterior circulation but there is no guideline for optimal therapy for patients with posterior circulation stroke, specifically basilar artery occlusion (BAO) outside the standard IV rt-PA treatment window.AimTo evaluate differences in outcomes between maximal medical treatment versus thrombectomy in BAO.MethodWe retrospectively evaluated prospectively collected acute stroke code patients from our stroke registry from 7/2004 to 7/2016. Patients who received IV rt-PA were excluded. Patients with evidence of posterior circulation ischemia and a hyper dense artery sign on initial non-contrast CT were included as a surrogate for direct vessel data before 2014. Patients after 9/2014 were selected by evidence of BAO on vessel imaging. All patients were categorized either as endovascular therapy or standard medical treatment alone. Demographics, hospital discharge location and Modified Rankin Scale (mRS) at 90 days were compared. Two-sample t-test and Fisher’s exact test compared continuous and categorical variables across groups respectively.ResultsA total of 18 patients were included (three embolectomy and 15 medical therapy only). There were no significant differences in demographic data (age, gender, race, ethnicity, blood pressure, diabetes mellitus, hypertension, atrial fibrillation, tobacco use, alcohol use and initial NIHSS). Results for outcome and efficacies showed no statistical difference between medical management and endovascular intervention for functional outcome mRS (0-3) at 90 days (p = 0.2) and discharge location of home/inpatient rehabilitation vs other locations (p = 0.52).ConclusionsOur single-center review showed the expected transition from predominantly medically treated posterior circulation BAOs, to a mixed pattern including embolectomy. Although the sample size was small, this study also illustrates the lack of clear efficacy data for optimal treatment strategies, and the ongoing treatment challenges in posterior circulation stroke population in a population of patients outside the rt-PA window.

Aortic dissection masquerading as a code stroke: A single-centre cohort study.

IntroductionData on the incidence of acute aortic dissection in the code stroke population are scarce. We report estimated incidence, clinical manifestations, treatment and outcomes of patients with an acute aortic dissection in a code stroke cohort from a comprehensive stroke centre.Patients and methodsWe used data from a single-centre prospective registry of consecutive adult patients who presented to the emergency department between 2015 and 2018 with neurological deficits suggestive of an acute stroke (‘code stroke’). All patients routinely underwent non-contrast computed tomography of the brain and computed tomography-angiography of the aortic arch, cervical and intracranial arteries.ResultsOf 2874 code stroke patients, 1563 (54.4%) had acute ischaemia (ischaemic stroke or transient ischaemic attack). Fifteen patients (0.5% of code stroke patients and 0.8% of patients with acute ischaemia) had an acute aortic dissection (all Stanford classification type A). Discerning clinical manifestations were decreased consciousness in 11/15 (73%), pain in 8/15 (53%) and low systolic blood pressure (mean 106 mmHg, SD30). Acute aortic dissection was an incidental finding during computed tomography-angiography in 4/15 (27%). Two out of 15 patients (13%) received intravenous thrombolysis, 9/15 (60%) underwent aortic surgery and 10/15 (67%) died. Of those who survived, 3/5 (60%) had a good functional outcome (modified Rankin Scale 0–2).Discussion and ConclusionIn our comprehensive stroke centre, about 1/200 code stroke patients and 1/125 patients with acute ischaemia had an acute aortic dissection. Multicentre studies are necessary to acquire a more reliable estimate of the incidence of acute aortic dissection in the code stroke population. Given the ramifications of missing this diagnosis, imaging of the entire aortic arch is important in these patients.

A Unique Signature of Cardiac-Induced Cranial Forces During Acute Large Vessel Stroke and Development of a Predictive Model.

Cranial accelerometry is used to detect cerebral vasospasm and concussion. We explored this technique in a cohort of code stroke patients to see whether a signature could be identified to aid in the diagnosis of large vessel occlusion (LVO) stroke. A military-grade three-axis accelerometer was affixed to a headset. Accelerometer and electrocardiogram (ECG) outputs were digitized at 1.6kHz. We call the resulting digitized signals the "headpulse." Three-minute recordings were performed immediately after computed tomography (CT) angiography (CTA) and/or immediately before and after attempted mechanical thrombectomy in patents with suspected stroke. The resulting waveforms were inspected by eye and then subjected to supervised machine learning (MATLAB Classification Learner R2018a) to train a model using fivefold cross-validation. Of 42 code stroke subjects with recordings, 19 (45%) had LVO and 23 (55%) had normal CTAs. In patients without LVO, ECG-triggered waveforms followed a self-similar time course revealing that the headpulse is highly coupled to the cardiac contraction. However, in most patients with LVO, headpulses showed little cardiac contraction correlation. We term this abnormality "chaos" and parameterized it with 156 measures of trace-by-trace variation from the ECG-signal-averaged mean for machine learning model training. Selecting the best model, using biometric data only, we properly classified 15/19 LVOs and 20/23 non-LVO patients, with receiver operating characteristic curve area = 0.79, sensitivity of 73%, and specificity of 87%, P < 0.0001. Headpulse waveforms following thrombectomy showed return of cardiac contraction correlation. Headpulse recordings performed on patients with suspected acute stroke significantly identify those with LVO. The lack of temporal correlation of the headpulse with cardiac contraction and resolution to normal may reflect changes in cerebral blood flow and may provide a useful technique to triage stroke patients for thrombectomy using a noninvasive device.

Mapping a Reliable Stroke Onset Time Course Using Signal Intensity on DWI Scans.

Identifying a last known well (LKW) time surrogate for acute stroke is vital to increase stroke treatment. Diffusion-weighted imaging (DWI) signal intensity initially increases from onset of stroke but mapping a reliable time course to the signal intensity has not been demonstrated. We retrospectively reviewed stroke code patients between 1/2016 and 6/2017 from the prospective; Institutional review board (IRB) approved University of California San Diego Stroke Registry. Patients who had magnetic resonance imaging of brain from onset, with or without intervention, are included. All ischemic strokes were confirmed and timing from onset to imaging was calculated. Raw DWI intensity is measured using IMPAX software and compared to contralateral side for control for a relative DWI intensity (rDWI). LKW and magnetic resonance imaging (MRI) time were collected by chart review. Correlation is assessed using Pearson correlation coefficient between DWI intensity, rDWI, and time to MRI imaging. 1.5T, 3T, and combined modalities were examined. Seventy-eight patients were included in this analysis. Overall, there was statistically significant positive correlation (.53, P < .001) between DWI intensity and LKW time irrespective of scanner strength. Using 1.5T analyses, there was good correlation (.46, P < .001). 3T MRI analysis further showed comparatively stronger positive correlation (.66, P < .001). There is good correlation between DWI intensity and minutes from onset to MRI. This suggests a time-dependent DWI intensity response and supports the potential use of DWI intensity measurements to extrapolate an LKW time. Further studies are being pursued to increase both experience and generalizability.

Impact of prehospital stroke code in a public center in Paraguay: A pilot study.

Prehospital stroke code activation results in reduced pre- and in-hospital delays and triage and transport of stroke patients to the right centers. In Paraguay, data about acute reper fusion treatment are not available. Recently, a pilot prehospital stroke code program was implemented in the country in November 2016. In an observational, single-center cohort study with a before-after design, from April 2015 to July 2018, we found that 193/832 (23.1%) of stroke patients were stroke code activated, and from these, 54 (6.5%) were brought to hospital under the prehospital stroke code protocol. Fifty-eight patients (58 alteplase and 2 additional endovascular treatment) received reperfusion therapy. Prehospital stroke code patients had a lower mean door-to-CT time (24 vs. 33 min, p = 0.021) and lower mean door-to-needle time (35.3 vs.76.3 min, p < 0.001) compared to in-hospital stroke code patients. Prehospital stroke code is feasible in Paraguay and has a positive impact on in-hospital acute stroke management, reducing delays and increasing the rates of reperfusion treatments.

Abstract WP378: RAcial Disparities in Ich After iv-tpA and Neurointerventional Treatment (RADIANT)

Introduction: Studies have reported ethnic/racial disparities in intravenous tPA treatment. The outcome of tPA and/or intra-arterial intervention (IA) among different ethnicities/races requires investigation. The purpose of the study was to examine the symptomatic intracranial hemorrhage (SxICH) and major systemic hemorrhage (MSH) after acute stroke treatment among different ethnicities/races. Methods: We retrospectively reviewed all stroke code patients from an IRB- approved stroke code registry between June 2004 and June 2018. We identified patients who received either IV tPA, IA, or IV tPA+IA. Demographics, clinical presentation, co-morbidities, stroke treatments, and adverse outcomes were collected. Patients were classified into two ethnic groups - Hispanics or non-Hispanics (H/NH) and four racial groups- Asians, Black, Others (includes Native Americans and Pacific Islanders), and White (A/B/O/W). Results: We identified 916 patients that received acute therapy (A/B/O/W: n=50/104/16/746, H/NH: n= 184/730). For those received IV tPA only (n=759), the overall SxICH rate was 4.3% (A/B/O/W: 8.1%/6.6%/8.3%/3.7%, p=0.17; H/NH: 5.7%/4.1%, p=0.42), and the MSH rate was 1.3% (A/B/O/W: 2.7%/1.1%/0%/1.3%, p=0.55; H/NH=1.4%/1.3%, p=1.00). White race was significantly correlated with lower SxICH rate after IV tPA (OR 0.07, p=0.02). There was a significant correlation between age and baseline NIHSS with SxICH (p&lt;0.01, p=0.02, respectively). Age, INR and PTT were independent predictors of SxICH after IV tPA (OR 1.06, 46.52 and 1.18, p= 0.02, 0.04 and 0.04, respectively). For IA only (n=85), the rate of SxICH was 4.7% (A/B/O/W: 0%/0%/25%/4.5%, p=0.31; H/NH: 0%/ 6.1%, p=0.57), and 6.9% for IV tPA+IA (A/B/W: 0%/16.7%/6.6%, p=0.59; H/NH: 4.2%/8.3%, p=0.66). There was no MSH in IA only or IV tPA+IA groups. Conclusions: White race correlated with a significantly lower rate of SxICH after IV tPA. There was no significant difference in the rate of SxICH or MSH after IV tPA, IA, or IV tPA+IA among different racial or ethnic groups in this study. Larger studies are needed to elucidate the race specific causes of these SxICH and MSH after acute stroke treatment.

Abstract WP327: CT Angiogram Has High Yield in Code Stroke

Introduction: Although studies have examined emergent CTAs of the head and neck in patients seen by neurologists who are suspected of having a large vessel occlusion, the utility and accuracy of CTA for patients called as a ‘code stroke’ by any healthcare provider has not been evaluated. Methods: At our institution, imaging for all Code Stroke patients includes non-contrast CT of the brain as well as CTA of the neck and brain, regardless of severity. This imaging is often performed prior to detailed neurology evaluation. We queried our radiology department report database for all studies labelled ‘CTA ELVO’, an imaging order code which is specific for Code Stroke. We then cross-referenced this list with our prospectively acquired ischemic stroke registry, which consists of all patients discharged with a diagnosis of acute ischemic stroke. Results: Between January and August 2017, 1265 CTA ELVOs were performed. Average age was 66.3 years, and 52.4% were female. Of all CTA ELVOs, 144 were performed on inpatients (11.3%) and neuroradiologists read 149 studies (11.8%). Critical findings on vessel imaging were present in 165 studies (13%); of these 118 patients were ultimately diagnosed with acute ischemic stroke. Studies with critical findings involved older patients (73.7 years, p&lt;0.001) and were less likely to be performed on inpatients (29 studies, p=0.012) but were no different in number of females (55%, p=0.51) or whether read by a neuroradiologist (23 studies, p=0.36). Critical findings included acute intracranial large vessel occlusion involving the middle cerebral artery, intracranial internal carotid artery (ICA), or basilar artery (87 studies); critical cervical ICA stenosis, acute cervical ICA occlusion, or acute dissection (42 studies); M2 occlusion (32 studies); critical intracranial stenosis (7 studies) and vascular malformation such as aneurysm or arteriovenous malformation (6 studies). Conclusion: The yield of non-invasive vessel imaging in patients called as a code stroke in detecting critical findings is high, revealing abnormalities in approximately one in eight patients. Patients presenting with acute neurologic symptoms should receive vessel imaging as part of the initial workup for suspected stroke.

Abstract TMP72: Detection of a Novel Signal of Large Vessel Occlusion Stroke Using Cranial Accelerometry- The Headpulse

Introduction: Cranial accelerometry is used to detect cerebral vasospasm and concussion. We explored this technique in a cohort of code stroke patients to see if a signature could be identified to aid in the diagnosis of large vessel occlusion (LVO) stroke. Methods: A military-grade 3-axis accelerometer was affixed to a headset. Accelerometer output and ECG was digitized at 1.6Khz. The resulting digitized signals we call the “Headpulse”. Three-minute recordings were performed immediately after CTA and/or immediately before and after attempted mechanical thrombectomy. The resulting waveforms were inspected by eye then subjected to supervised machine learning (MATLAB Classification Learner R2018a) to train a model using 5-fold cross validation. Results: Of 42 code stroke subjects with recordings, 18 (43%) had LVO and 24 (57%) had normal CTAs. In patients without LVO, ECG-triggered waveforms followed a tightly similar time-course revealing that the Headpulse is highly coupled to the cardiac contraction (Figure A - small vessel stroke; Figure B - stroke mimic migraine). However, in LVO patients many recordings showed little correlation with the ECG (Figure 1 C). This abnormality we term “chaos” and parameterized it with 176 measures of trace-by-trace variation from the ECG-signal-averaged mean for machine learning model training. Selecting the best model, using biometric data only, we properly classified 15/18 LVOs and 18/24 non-LVO patients (p=0.0002, Fisher’s exact test). Headpulse waveforms following thrombectomy showed return of cardiac contraction correlation (Figures C and D). Conclusions: Headpulse recordings reveal a unique signature in LVO patients during acute stroke. This lack of correlation of the Headpulse with cardiac contraction and later return of correlation likely reflects changes of cerebral blood flow and may provide a useful technique to triage stroke patients using a non-invasive device.

Abstract TMP68: Simple Neurological Exam Combined With Headpulse Accurately Predicts Large Vessel Occlusion Stroke

Introduction: Early prediction of whether or not a patient is having a large vessel occlusion (LVO) stroke could facilitate faster treatment through triage to an endovascular center. Clinical LVO stroke prediction scales achieve accuracies near 80%. We developed a non-invasive device to measure the Headpulse (imperceptible head movements due to the cardiac contraction detected by cranial accelerometry) and used this biometric data and a stroke scale to predict LVO. Methods: Academic hospital emergency department and transfer code stroke patients had a 3-minute Headpulse recording after CTA and prior to thrombectomy when applicable. Intracranial hemorrhage patients were excluded. We quantified the variance of Headpulse recordings from one cardiac cycle to the next and used supervised machine learning (MATLAB Classification Learner R2018a) with 5-fold cross validation to train a model. This was repeated after adding the SAVE scale (1 point for each of Speech abnormality, asymmetric Arm weakness, Vision deficit, Eye deviation). Patients were classified as LVO if there was an occlusion of the ICA, M1, M2, vertebral, or basilar arteries on CTA or non-LVO if the CTA was normal or showed only more distal occlusion(s). Results: 42 patients were included. Of 18 LVO patients there were 3 ICA, 1 basilar, 10 M1, and 4 M2 occlusions. Of 24 non-LVO patients there were 11 ischemic strokes, 2 TIAs, and 11 stroke mimics. Adding SAVE to the training data resulted in a classification tree with 'asymmetric arm weakness' as the first node due to its high accuracy. Subsequent Headpulse nodes led to correct classification of all patients that would be false positives by clinical exam alone. Conclusions: In a highly selected derivation cohort, clinical exam correctly classified LVO patients 93% of the time. Addition of a biometric derived from cranial accelerometry improved this accuracy. Validation in a representative code stroke cohort with intracranial hemorrhage patients is required.

Diagnosing cerebral ischemia with door-to-thrombolysis times below 20 minutes.

To clarify diagnostic accuracy and consequences of misdiagnosis in the admission evaluation of stroke-code patients in a neurologic emergency department with less than 20-minute door-to-thrombolysis times. Accuracy of admission diagnostics was studied in an observational cohort of 1,015 stroke-code patients arriving by ambulance as candidates for recanalization therapy between May 2013 and November 2015. Immediate admission evaluation was performed by a stroke neurologist or a neurology resident with dedicated stroke training, primarily utilizing CT-based imaging. The rate of correct admission diagnosis was 91.1% (604/663) for acute cerebral ischemia (ischemic stroke/TIA), 99.2% (117/118) for hemorrhagic stroke, and 61.5% (144/234) for stroke mimics. Of the 150 (14.8%) misdiagnosed patients, 135 (90.0%) had no acute findings on initial imaging and 100 (67.6%) presented with NIH Stroke Scale score 0 to 2. Misdiagnosis altered medical management in 70 cases, including administration of unnecessary treatments (thrombolysis n = 13, other n = 24), omission of thrombolysis (n = 5), delays to specific treatments of stroke mimics (n = 13, median 56 [31-93] hours), and delays to antiplatelet medication (n = 14, median 1 [1-2] day). Misdiagnosis extended emergency department stay (median 6.6 [4.7-10.4] vs 5.8 [3.7-9.2] hours; p = 0.001) and led to unnecessary stroke unit stay (n = 10). Detailed review revealed 8 cases (0.8%) in which misdiagnosis was possible or likely to have worsened outcomes, but no death occurred as a result of misdiagnosis. Our findings support the safety of highly optimized door-to-needle times, built on thorough training in a large-volume, centralized stroke service with long-standing experience. Augmented imaging and front-loaded specialist engagement are warranted to further improve rapid stroke diagnostics.