Predictors of devastating functional outcome despite successful basilar thrombectomy

BACKGROUND

Basilar thrombosis frequently leads to poor functional outcomes, even with good endovascular reperfusion. We studied factors associated with severe disability or death in basilar thrombectomy patients achieving revascularization.

METHODS

We retrospectively analyzed records from a health system's code stroke registry, including successful basilar thrombectomy patients from January 2017 to May 2023 who were evaluated with pretreatment computed tomography perfusion. The primary outcome was devastating functional outcome (90-day modified Rankin Scale [mRS] score 5-6). A multivariable logistic regression model was constructed to determine independent predictors of the primary outcome. The area under the receiver operator characteristics curve (AUC) was calculated for the model distinguishing good from devastating outcome.

RESULTS

Among 64 included subjects, with mean (standard deviation) age 65.6 (14.1) years and median (interquartile range) National Institutes of Health Stroke Scale (NIHSS) 18 (5.75-24.5), the primary outcome occurred in 28 of 64 (43.8%) subjects. Presenting NIHSS (odds ratio [OR] 1.08, 95% confidence interval [CI] 1.01-1.14, p = 0.02), initial glucose (OR 0.99, 95% CI 0.97-1.00, p < 0.05), and proximal occlusion site (OR 7.38, 95% CI 1.84-29.60, p < 0.01) were independently associated with 90-day mRS 5-6. The AUC for the multivariable model distinguishing outcomes was 0.81 (95% CI 0.70-0.92).

CONCLUSION

We have identified presenting stroke severity, lower glucose, and proximal basilar occlusion as predictors of devastating neurological outcome in successful basilar thrombectomy patients. These factors may be used in medical decision making or for patient selection in future clinical trials.

The Charlotte Large artery occlusion Endovascular therapy Outcome Score predicts independent outcome after thrombectomy

BACKGROUND AND PURPOSE

Predicting functional outcomes after endovascular thrombectomy (EVT) is of interest to patients and families as they navigate hospital and post-acute care decision-making. We evaluated the prognostic ability of several scales to predict good neurological function after EVT.

METHODS

We retrospectively analyzed records from a health system's code stroke registry, including consecutive successful thrombectomy patients from August 2020 to February 2023 presenting with an anterior circulation large vessel occlusion who were evaluated with pre-EVT CT perfusion. Primary and secondary outcomes were 90-day modified Rankin Scale (mRS) scores 0-2 and 0-1, respectively. Logistic regression was performed to evaluate the ability of each scale to predict the outcomes. Scales were compared by calculating the area under the curve (AUC).

RESULTS

A total of 465 patients (mean age 68.1 [±14.9] years, median National Institutes of Health Stroke Scale [NIHSS] 16 [11-21]) met inclusion criteria. In the logistic regression, the Charlotte Large artery occlusion Endovascular therapy Outcome Score (CLEOS), Totaled Health Risks in Vascular Events, Houston Intra-Arterial Therapy-2, Pittsburgh Response to Endovascular therapy, and Stroke Prognostication using Age and NIHSS were significant in predicting the primary and secondary outcomes. CLEOS was superior to all other scales in predicting 90-day mRS 0-2 (AUC .75, 95% confidence interval [CI] .70-.80) and mRS 0-1 (AUC .74, 95% CI .69-.78). Twenty of 22 patients (90.9%) with CLEOS <315 had 90-day mRS 0-2.

CONCLUSIONS

CLEOS predicts independent and excellent neurological function after anterior circulation EVT.

Predicting severe disability or death in endovascular thrombectomy with large computed tomography perfusion core infarction and limited penumbra

BACKGROUND

Patients presenting with large core infarctions benefit from treatment with endovascular thrombectomy (EVT), with a notable 50% reduction in rates of severe disability (modified Rankin Scale [mRS] 5) at 90 days. We studied the ability of previously reported prognostic scales to predict devastating outcomes in patients with a large ischemic core and limited salvageable brain tissue.

METHODS

Retrospective analysis from a health system's code stroke registry, including consecutive thrombectomy patients from November 2017 to December 2022 with an anterior circulation large vessel occlusion, computed tomography perfusion core infarct ≥ 50 ml, and mismatch volume < 15 ml or mismatch ratio < 1.8. Previously reported scales were compared using logistic regression and area under the curve (AUC) analyses to predict 90-day mRS 5-6.

RESULTS

Sixty patients (mean age 62.38 ± 14.25 years, median core volume 103 ml [74.75-153]) met inclusion criteria, of whom 27 (45%) had 90-day mRS 5-6. The Charlotte Large artery occlusion endovascular therapy Outcome Score (CLEOS) (odds ratio [OR] 1.35, 95% CI [1.14-1.60], p = 0.0005), Houston Intra-Arterial Therapy-2 (OR 1.35, 95% CI [1.00-1.83], p = 0.0470), and Totaled Health Risks in Vascular Events (OR 1.53, 95% CI [1.07-2.18], p = 0.0199) predicted the primary outcome in the logistic regression analysis. CLEOS performed best in the AUC analysis (AUC 0.83, 95% CI [0.72-0.94]).

CONCLUSION

CLEOS predicts devastating outcomes after EVT in patients with large core infarctions and small volumes of ischemic penumbra.

A Telestroke Nurse and Neuroradiologist Model for Extended Window Code Stroke Triage

ABSTRACT

BACKGROUND: Distinguishing features of our stroke network include routine involvement of a telestroke nurse (TSRN) for code stroke activations at nonthrombectomy centers and immediate availability of neuroradiologists for imaging interpretation. On May 1, 2021, we implemented a new workflow for code stroke activations presenting beyond 4.5 hours from last known well that relied on a TSRN supported by a neuroradiologist for initial triage. Patients without a target large vessel occlusion (LVO) were managed without routine involvement of a teleneurologist, which represented a change from the preimplementation period. METHODS: We collected data 6 months before and after implementation of the new workflow. We compared preimplementation process metrics for patients managed with teleneurologist involvement with the postimplementation patients managed without teleneurologist involvement. RESULTS: With the new workflow, teleneurologist involvement decreased from 95% (n = 953) for patients presenting beyond 4.5 hours from last known well to 37% (n = 373; P < .001). Compared with patients in the preimplementation period, postimplementation patients without teleneurologist involvement experienced less inpatient hospital admission and observation (87% vs 90%; unadjusted P = .038, adjusted P = .06). Among the preimplementation and postimplementation admitted patients, there was no statistically significant difference in follow-up neurology consultation or nonstroke diagnoses. A similar percentage of LVO patients were transferred to the thrombectomy center (54% pre vs 49% post, P = .612), whereas more LVO transfers in the postimplementation cohort received thrombectomy therapy (75% post vs 39% pre, P = .014). Among LVO patients (48 pre and 41 post), no statistical significance was observed in imaging and management times. CONCLUSION: Our work shows the successful teaming of a TSRN and a neuroradiologist to triage acute stroke patients who present beyond an eligibility window for systemic thrombolysis, without negatively impacting care and process metrics. This innovative partnering may help to preserve the availability of teleneurologists by limiting their involvement when diagnostic imaging drives decision making.

The Charlotte Large Artery Occlusion Endovascular Therapy Outcome Score Compares Favorably to the Critical Area Perfusion Score for Prognostication Before Basilar Thrombectomy

INTRODUCTION

The Critical Area Perfusion Score (CAPS) predicts functional outcomes in vertebrobasilar thrombectomy patients based on computed tomography perfusion (CTP) hypoperfusion. We compared CAPS to the clinical-radiographic Charlotte Large artery occlusion Endovascular therapy Outcome Score (CLEOS).

METHODS

Acute basilar thrombosis patients from January 2017-December 2021 were included in this retrospective analysis from a health system's stroke registry. Inter-rater reliability was assessed for 6 CAPS raters. A logistic regression with CAPS and CLEOS as predictors was performed to predict 90-day modified Rankin Scale (mRS) score 4-6. Area under the curve (AUC) analyses were performed to evaluate prognostic ability.

RESULTS

55 patients, mean age 65.8 (± 13.1) years and median NIHSS score 15.5^5-24, were included. Light's kappa among 6 raters for favorable versus unfavorable CAPS was 0.633 (95% CI 0.497-0.785). Increased CLEOS was associated with elevated odds of a poor outcome (odds ratio (OR) 1.0010, 95% CI 1.0007-1.0014, p<0.01), though CAPS was not (OR 1.0028, 95% CI 0.9420-1.0676, p=0.93). An overall favorable trend was observed for CLEOS (AUC 0.69, 95% CI 0.54-0.84) versus CAPS (AUC 0.49, 95% CI 0.34-0.64; p=0.051). Among 85.5% of patients with endovascular reperfusion, CLEOS had a statistically higher sensitivity than CAPS at identifying poor 90-day outcomes (71% versus 21%, p=0.003).

CONCLUSIONS

CLEOS demonstrated better predictive ability than CAPS for poor outcomes overall and in patients achieving reperfusion after basilar thrombectomy.

The Charlotte Large Artery Occlusion Endovascular Therapy Outcome Score Predicts Poor Outcomes 1 Year After Endovascular Thrombectomy

OBJECTIVE

We evaluated the ability of several outcome prognostic scales to predict poor 1-year outcomes and mortality after endovascular thrombectomy.

METHODS

In this retrospective analysis from the stroke registry of a large integrated health system, consecutive patients presenting from August 2020 to September 2021 with an anterior circulation large-vessel occlusion stroke treated with endovascular thrombectomy were included. Multivariable logistic regression was performed to determine the ability of each scale to predict the primary outcome (1-year modified Rankin Scale [mRS] score of 4-6) and the secondary outcome (1-year mortality). Area under the curve analyses were performed for each scale.

RESULTS

In 237 included patients (mean age 68 [±15] years; median National Institutes of Health Stroke Scale score 16 [11-21]), poor 1-year outcomes were present in 116 patients (49%) and 1-year mortality was 34%. The CLEOS (Charlotte Large Artery Occlusion Endovascular Therapy Outcome Score), which incorporates age, baseline National Institutes of Health Stroke Scale score, initial glucose level, and computed tomography perfusion cerebral blood volume index, had a significant association with poor 1-year outcomes (per 25-point increase; odds ratio, 1.0134; P = 0.02). CLEOS and PRE (Pittsburgh Response to Endovascular Therapy) were both significantly associated with 1-year mortality. Area under the curve values were comparable for CLEOS, PRE, Houston Intra-Arterial Therapy 2, and Totaled Health Risks in Vascular Events to predict 1-year mRS score 4-6 and mortality. Only 1 of 18 patients with CLEOS ≥690 had a 1-year mRS score of 0-3.

CONCLUSIONS

CLEOS can predict poor 1-year outcomes and mortality for patients with anterior circulation large-vessel occlusion using prethrombectomy variables.

Transcranial ultrasonography to detect intracranial pathology: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Transcranial ultrasonography (TCU) can be a useful diagnostic tool in evaluating intracranial pathology in patients with limited or delayed access to routine neuroimaging in critical care or austere settings. We reviewed available literature investigating the diagnostic utility of TCU for detecting pediatric and adult patient's intracranial pathology in patients with intact skulls and reported diagnostic accuracy measures.

METHODS

We performed a systematic review of PubMed^® , Cochrane Library, Embase^® , Scopus^® , Web of Science™, and Cumulative Index to Nursing and Allied Health Literature databases to identify articles evaluating ultrasound-based detection of intracranial pathology in comparison to routine imaging using broad Medical Subject Heading sets. Two independent reviewers reviewed the retrieved articles for bias using the Quality Assessment of Diagnostic Accuracy Studies tools and extracted measures of diagnostic accuracy and ultrasound parameters. Data were pooled using meta-analysis implementing a random-effects approach to examine the sensitivity, specificity, and accuracy of ultrasound-based diagnosis.

RESULTS

A total of 44 studies out of the 3432 articles screened met the eligibility criteria, totaling 2426 patients (Mean age: 60.1 ± 14.52 years). We found tumors, intracranial hemorrhage (ICH), and neurodegenerative diseases in the eligible studies. Sensitivity, specificity, and accuracy of TCU and their 95% confidence intervals were 0.80 (0.72, 0.89), 0.71 (0.59, 0.82), and 0.76 (0.71, 0.82) for neurodegenerative diseases; 0.88 (0.74, 1.02), 0.81 (0.50, 1.12), and 0.94 (0.92, 0.96) for ICH; and 0.97 (0.92, 1.03), 0.99 (0.96, 1.01), and 0.99 (0.97, 1.01) for intracranial masses. No studies reported ultrasound presets.

CONCLUSIONS

TCU has a reasonable sensitivity and specificity for detecting intracranial pathology involving ICH and tumors with clinical applications in remote locations or where standard imaging is unavailable. Future studies should investigate ultrasound parameters to enhance diagnostic accuracy in diagnosing intracranial pathology.

Validation of the Charlotte large artery occlusion endovascular therapy outcome score using Viz.ai-derived cerebral blood volume index

BACKGROUND

The Charlotte large artery occlusion endovascular therapy outcome score (CLEOS) predicts poor 90-day outcomes for patients presenting with internal carotid artery (ICA) or middle cerebral artery (MCA) occlusions. It incorporates RAPID-derived cerebral blood volume (CBV) index, a marker of collateral circulation. We validated the predictive ability of CLEOS with Viz.ai-processed computed tomography perfusion (CTP) imaging.

METHODS

The original CLEOS derivation cohort was compared to a validation cohort consisting of all ICA and MCA thrombectomy patients treated at a large health system with Viz.ai-processed CTP. Rates of poor 90-day outcome (mRS 4-6) were compared in the derivation and validation cohorts, stratified by CLEOS. CLEOS was compared to previously described prediction models using area under the curve (AUC) analyses. Calibration of CLEOS was performed to compare predicted risk of poor outcomes with observed outcomes.

RESULTS

One-hundred eighty-one patients (mean age 66.4 years, median NIHSS 16) in the validation cohort were included. The validation cohort had higher median CTP core volumes (24 vs 8 ml) and smaller median mismatch volumes (81 vs 101 ml) than the derivation cohort. CLEOS-predicted poor outcomes strongly correlated with observed outcomes (R2 = 0.82). AUC for CLEOS in the validation cohort (0.72, 95% CI 0.64-0.80) was similar to the derivation cohort (AUC 0.75, 95% CI 0.70-0.80) and was comparable or superior to previously described prognostic models.

CONCLUSIONS

CLEOS can predict risk of poor 90-day outcomes in ICA and MCA thrombectomy patients evaluated with pre-intervention, Viz.ai-processed CTP.

Automated detection of intracranial large vessel occlusions using Viz.ai software: Experience in a large, integrated stroke network

BACKGROUND AND PURPOSE

Endovascular thrombectomy is an evidence-based treatment for large vessel occlusion (LVO) stroke. Commercially available artificial intelligence has been designed to detect the presence of an LVO on computed tomography angiogram (CTA). We compared Viz.ai-LVO (San Francisco, CA, USA) to CTA interpretation by board-certified neuroradiologists (NRs) in a large, integrated stroke network.

METHODS

From January 2021 to December 2021, we compared Viz.ai detection of an internal carotid artery (ICA) or middle cerebral artery first segment (MCA-M1) occlusion to the gold standard of CTA interpretation by board-certified NRs for all code stroke CTAs. On a monthly basis, sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Trend analyses were conducted to evaluate for any improvement of LVO detection by the software over time.

RESULTS

3851 patients met study inclusion criteria, of whom 220 (5.7%) had an ICA or MCA-M1 occlusion per NR. Sensitivity and specificity were 78.2% (95% CI 72%-83%) and 97% (95% CI 96%-98%), respectively. PPV was 61% (95% CI 55%-67%), NPV 99% (95% CI 98%-99%), and accuracy was 95.9% (95% CI 95.3%-96.5%). Neither specificity or sensitivity improved over time in the trend analysis.

CONCLUSIONS

Viz.ai-LVO has high specificity and moderately high sensitivity to detect an ICA or proximal MCA occlusion. The software has the potential to streamline code stroke workflows and may be particularly impactful when emergency access to NRs or vascular neurologists is limited.

The Charlotte large artery occlusion endovascular therapy outcome score predicts outcome after basilar artery thrombectomy

BACKGROUND AND PURPOSE

The Charlotte Large artery occlusion Endovascular therapy Outcome Score (CLEOS) and Totaled Health Risks in Vascular Events (THRIVE) predict functional outcomes after anterior circulation endovascular thrombectomy (EVT). We evaluated the performance of CLEOS and THRIVE in patients presenting with an acute basilar artery occlusion (BAO) treated with EVT.

METHODS

We conducted a retrospective analysis of a health system's stroke registry. Patients presenting with an acute BAO treated with EVT and evaluated with pre-thrombectomy CT perfusion (CTP) from January 2017 to December 2021 were included. CLEOS = (5 × age) + (10 × National Institutes of Health Stroke Scale [NIHSS]) + Glucose - (150 × CTP cerebral blood volume index) and THRIVE (0-9 points) = age 60-79 years, 1 point; age ≥ 80 years, 2 points; NIHSS 11-20, 2 points; NIHSS ≥ 21, 4 points; hypertension, diabetes mellitus, atrial fibrillation, 1 point each. Multivariable logistic regression was performed for the ability of CLEOS and THRIVE to predict the primary outcome, modified Rankin Scale score 3-6.

RESULTS

Fifty-seven patients had mean age 66.6 (± 14.9) years and median NIHSS 15.5 (5-24). In the multivariable regression analysis, increased CLEOS was associated with significantly higher odds of a poor functional outcome (odds ratio [OR] = 1.0011, 95% confidence interval [CI]: 1.0003-1.0019, p = .008), whereas THRIVE was not (OR = 1.0326, 95% CI: 0.9478-1.1250, p = .466). CLEOS &gt; 503 best predicted poor outcomes.

CONCLUSIONS

A higher CLEOS score was associated with elevated odds of a poor 90-day functional outcome in our cohort of acute BAO patients treated with EVT.

Endovascular Thrombectomy Reduces Risk of Poor Functional Outcomes in Patients Presenting within 0-6 Hours with Large Ischemic Core Volumes on Computed Tomography Perfusion

INTRODUCTION

Patients presenting with large ischemic core volumes (LICVs) on computed tomography perfusion (CTP) are at high risk for poor functional outcomes. We sought to identify predictors of outcome in patients with an internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion and LICV.

METHODS

A large healthcare system's prospectively collected code stroke registry was utilized for this retrospective analysis of patients presenting within 6 hours with at least 50 ml of CTP reduced relative cerebral blood flow (CBF) < 30%. A multivariable logistic regression model was constructed to identify independent predictors (p < 0.05) of poor discharge outcome (modified Rankin scale score 4-6).

RESULTS

Over a 38-month period, we identified 104 patients meeting inclusion criteria, with a mean age of 65.4 ± 16.2 years, median presenting National Institutes of Health Stroke Scale score 20 (IQR 16-24), median ischemic core volume (CBF < 30%) 82 ml (IQR 61-118), and median mismatch volume 80 ml (IQR 56-134). Seventy-five patients (72.1%) had a discharge modified Rankin scale score of 4-6. Sixty-six of 104 (63.5%) patients were treated with endovascular thrombectomy (EVT). In the multivariable regression model, EVT (OR 0.303; 95% CI 0.080-0.985; p = 0.049) and lower blood glucose (per 1-point increase, OR 1.014; 95% CI 1.003-1.030; p = 0.030) were independently protective against poor discharge outcome.

CONCLUSIONS

EVT is independently associated with a reduced risk of poor functional outcome in patients presenting within 6 hours with ICA or MCA occlusions and LICV.

Visualization of the Anterior Temporal Artery as a Predictor of Outcome in Middle Cerebral Artery Occlusion Patients Achieving Successful Recanalization After Transfer

Introduction

Anterior temporal artery (ATA) visualization on computed tomography angiography (CTA) has been previously associated with good outcomes in middle cerebral artery (MCA) occlusions, but not in the setting of patients who initially present to non-thrombectomy centers.

Methods

We retrospectively identified acute MCA (M1) occlusion patients who underwent mechanical thrombectomy after transfer from non-thrombectomy-capable centers. Neuroradiologists confirmed the MCA (M1) as the most proximal site of occlusion on CTA and assessed for visualization of the ATA. Thrombolysis in Cerebral Infarction (TICI) 2b or greater revascularization scores were confirmed by neurointerventionalists blinded to patient outcomes. Ninety-day modified Rankin scale (mRS) scores were obtained via a structured telephone questionnaire.

Results

We identified 102 M1 occlusion patients over a three-and-a-half-year period presenting to a non-thrombectomy-capable center who underwent transfer and mechanical thrombectomy. There were no significant differences in age, gender, race, comorbidities, or median National Institute of Health Stroke Scale (NIHSS) scores between the ATA visualized (n = 47) versus non-visualized (n = 55) cohort, and no significant differences in baseline Alberta Stroke Program Early Computed Tomography (ASPECT) scores, post-intervention TICI scores, or interval from last known well to revascularization. There was a strong trend in functional independent outcome (mRS ≤ 2) for patients with ATA visualization (63.8% vs. 45.5%, p = 0.064).

Conclusion

For patients presenting to non-thrombectomy centers without CT perfusion capability, ATA visualization should be further investigated as an outcome predictor, given its association with functional independence after successful recanalization.

This article was previously presented as a meeting abstract at the 2021 International Stroke Conference on March 17-19, 2021.

Association of Recent Use of Non-Vitamin K Antagonist Oral Anticoagulants With Intracranial Hemorrhage Among Patients With Acute Ischemic Stroke Treated With Alteplase

IMPORTANCE

Current guidelines recommend against use of intravenous alteplase in patients with acute ischemic stroke who are taking non-vitamin K antagonist oral anticoagulants (NOACs).

OBJECTIVE

To evaluate the safety and functional outcomes of intravenous alteplase among patients who were taking NOACs prior to stroke and compare outcomes with patients who were not taking long-term anticoagulants.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study of 163 038 patients with acute ischemic stroke either taking NOACs or not taking anticoagulants prior to stroke and treated with intravenous alteplase within 4.5 hours of symptom onset at 1752 US hospitals participating in the Get With The Guidelines-Stroke program between April 2015 and March 2020, with complementary data from the Addressing Real-world Anticoagulant Management Issues in Stroke registry.

EXPOSURES

Prestroke treatment with NOACs within 7 days prior to alteplase treatment.

MAIN OUTCOMES AND MEASURES

The primary outcome was symptomatic intracranial hemorrhage occurring within 36 hours after intravenous alteplase administration. There were 4 secondary safety outcomes, including inpatient mortality, and 7 secondary functional outcomes assessed at hospital discharge, including the proportion of patients discharged home.

RESULTS

Of 163 038 patients treated with intravenous alteplase (median age, 70 [IQR, 59 to 81] years; 49.1% women), 2207 (1.4%) were taking NOACs and 160 831 (98.6%) were not taking anticoagulants prior to their stroke. Patients taking NOACs were older (median age, 75 [IQR, 64 to 82] years vs 70 [IQR, 58 to 81] years for those not taking anticoagulants), had a higher prevalence of cardiovascular comorbidities, and experienced more severe strokes (median National Institutes of Health Stroke Scale score, 10 [IQR, 5 to 17] vs 7 [IQR, 4 to 14]) (all standardized differences >10). The unadjusted rate of symptomatic intracranial hemorrhage was 3.7% (95% CI, 2.9% to 4.5%) for patients taking NOACs vs 3.2% (95% CI, 3.1% to 3.3%) for patients not taking anticoagulants. After adjusting for baseline clinical factors, the risk of symptomatic intracranial hemorrhage was not significantly different between groups (adjusted odds ratio [OR], 0.88 [95% CI, 0.70 to 1.10]; adjusted risk difference [RD], -0.51% [95% CI, -1.36% to 0.34%]). There were no significant differences in the secondary safety outcomes, including inpatient mortality (6.3% for patients taking NOACs vs 4.9% for patients not taking anticoagulants; adjusted OR, 0.84 [95% CI, 0.69 to 1.01]; adjusted RD, -1.20% [95% CI, -2.39% to -0%]). Of the secondary functional outcomes, 4 of 7 showed significant differences in favor of the NOAC group after adjustment, including the proportion of patients discharged home (45.9% vs 53.6% for patients not taking anticoagulants; adjusted OR, 1.17 [95% CI, 1.06 to 1.29]; adjusted RD, 3.84% [95% CI, 1.46% to 6.22%]).

CONCLUSIONS AND RELEVANCE

Among patients with acute ischemic stroke treated with intravenous alteplase, use of NOACs within the preceding 7 days, compared with no use of anticoagulants, was not associated with a significantly increased risk of intracranial hemorrhage.

Abstract WMP26: Performance Improvement During A Pandemic: Implementing Weekly Case Review To Decrease Door-to-CT And Door-to-Needle Times For Code Stroke Patients

Background and Purpose: When reviewing Code Stroke workflow data early in the COVID pandemic, a delay in obtaining CT brain imaging for stroke patients was identified. This study was aimed at improving Door-to-CT and Door-to-IVtPA bolus times by developing an Emergency Department (ED) led process improvement (PI) team to identify and track root causes for delays, provide feedback after fallouts, and recognize care teams after successful cases. Our primary goal was to demonstrate improved trends for performance metrics utilizing a novel method of process improvement, data collection, analysis, and dissemination.

Methods: All ED patients activated as a Code Stroke were included in a weekly workflow review conducted by the PI team. Patients with a Door-to-CT of > 20 minutes were analyzed by the team via an in-depth chart review to identify the root cause of the delay. Specific metrics analyzed included Door-to-CT times and Door-to-IVtPA bolus times, along with the percentage of cases that met process metric time goals. Implementation of the weekly review began September 31, 2020, with the pre-implementation period corresponding to the prior nine months and the post-implementation period being the ensuing nine months. Metrics were analyzed using a control chart based on monthly metric averages, standard deviations (SD), and both an upper and lower control limit defined as 1 sigma level of variability from the average.

Results: The average Door-to-CT time pre-implementation was 30.6 minutes versus 22.8 minutes post-implementation, with a percentage goal within 20 minutes pre- and post-implementation of 47% and 66%.The average Door-to-IVtPA Bolus time pre-implementation was 40.1 minutes versus 31.5 minutes post-implementation, with a percentage goal <30 minutes pre and post-implementation of 42% and 56%.The SD for Door-to-CT average improved from 4.81 to 3.76, while the Door-to-IVtPA Bolus average SD decreased from 9.26 to 8.53.

Conclusion: Reviewing identification, activation, and treatment times for all ED Code Stroke patients during the COVID pandemic was associated with significantly reduced imaging and treatment times.

Abstract TMP71: Optimizing Stroke Outcome Prediction: Derivation And Validation Of The Charlotte Large Artery Occlusion Endovascular Therapy Outcome Score

Introduction: Prognostic scores for large artery occlusion patients treated with endovascular intervention have not incorporated CTP parameters. We derived the Charlotte Large artery occlusion Endovascular therapy Outcome Score (CLEOS) to optimize outcome prediction after mechanical thrombectomy.

Methods: Patients presenting with an ICA or MCA occlusion treated with thrombectomy from November 2016-July 2020 were included from our health system’s prospectively collected, code stroke registry in the derivation analysis. Prognostic factors independently associated with poor outcomes (90-day mRS score 4-6) were combined with CTP parameters in a regression model. Internal cross-validation was performed. A separate, prospective validation cohort was included from the registry with patients from December 2020-April 2021. The final scale was compared to previously reported scales using Area Under the Curve-Receiver Operator Characteristic analysis.

Results: 646 patients were included in the derivation analysis and 60 patients in the separate validation cohort. CLEOS = (6 x Age) + (13 x NIHSS) + Glucose - (162 x CBV Index). CLEOS predicted poor 90-day outcomes (AUC 0.74, 95% CI 0.71-0.78) better than the Stroke Prognostication using Age and National Institute of Health Stroke Scale-100 Index (AUC 0.63, p < 0.0001), the Houston Intra-Arterial Therapy 2 score (AUC 0.69, p = 0.0029), and the Pittsburgh Response to Endovascular therapy score (AUC 0.71, p = 0.0240) in a combined analysis of the derivation and validation cohorts. Patients with CLEOS scores ≥ 850 did not have a lower risk of poor 90-day outcomes despite excellent revascularization (modified TICI 2c-3).

Conclusions: CLEOS can predict poor 90-day outcomes after an ICA or MCA occlusion and help identify patients unlikely to benefit from endovascular thrombectomy despite excellent revascularization.

Abstract NS5: A Telestroke Nurse/Neuroradiologist Model For Extended Window Code Stroke Triage

Background and Purpose: Two distinguishing features of our stroke network include the routine involvement of a telestroke nurse (TSRN) for code stroke activations at non-thrombectomy centers, and immediate availability of neuroradiologist for imaging interpretation. With revascularization treatment decision making for patients presenting beyond 4.5 hours from last known well (LKW) being driven by imaging, we hypothesized that reliance on those resources could substantially decrease the routine involvement of a teleneurologist.

Methods: On May 1, 2021, we implemented a workflow for code stroke activations beyond 4.5 hours from LKW that relied on a TSRN supported by a neuroradiologist. Criteria for a code stroke activation included any cortical sign on exam or suspicion for a basilar artery occlusion, as determined by the treating Emergency Medicine (EM) physician. All qualifying patients underwent a CTA with or without CTP imaging. Patients with a target occlusion on CTA confirmed by the neuroradiologist, the neurointerventionalist and neurologist at the thrombectomy center are immediately contacted to join the triaging team. Patients without a target occlusion on CTA are managed without the involvement of a teleneurologist, unless requested by the treating EM physician.

Results: In our first 3 months utilizing this workflow, there were 509 extended window code stroke activations. In 64% (n=326) of these cases, a teleneurologist was not initially involved, representing a cumulative 58% absolute decrease in teleneurology consultations when compared to the prior three months. For 95% (n=311) of those cases, a target LVO was not identified. For the 15 LVO cases, the median CTA acquisition to LVO confirmation time was 14 minutes (IQR 11-25.5). Ninety-five percent (n=311) of non-LVO cases were subsequently managed by the EM physician. Of those cases, 90% (n=292) were admitted to the hospital. For 47% (n=138) of admitted cases, the patient had a non-stroke diagnosis. Thirty-nine percent (n=114) of all admitted cases were managed by a hospitalist physician without a neurology consult.

Conclusions: A telestroke nurse/neuroradiologist model for extended window code stroke triage can substantially reduce the routine involvement of a teleneurologist.

Abstract TP104: Agreement Of Hypoperfusion Intensity Ratio On CTP Derived By Rapid AI And Viz AI

Background: For anterior circulation large vessel occlusion acute ischemic stroke patients, Hypoperfusion Intensity Ratio (HIR) derived from automated Computerized Tomography Perfusion (CTP) software has been shown to predict the rate of collateral flow, speed of infarct growth, and clinical outcome. Published data have proposed an HIR threshold derived by RAPID AI (Menlo Park, CA) of either <0.5 or <0.4 as best predicting robust collaterals. The agreement between HIR derived from VIZ AI (San Mateo, CA) compared to RAPID AI is unknown.

Methods: We identified 107 cases in which the middle cerebral artery was the most proximal site of occlusion on Computerized Tomography Angiography as confirmed by a neuroradiologist, and for whom a CTP performed on RAPID AI was diagnostic (e.g. lacking artifact from head motion, a failed bolus injection, poor scan timing, or low signal-to-noise). Those CTP acquisition data were subsequently processed on VIZ AI. We measured the agreement for HIR dichotomized at both <0.5 and <0.4 between RAPID AI and VIZ AI, along with the overall agreement.

Results: For the HIR dichotomized at <0.5, the simple kappa coefficient between HIR derived from VIZ AI compared to RAPID AI was 0.714 (95% CI 0.581-0.846), versus 0.636 (95% CI 0.500-0.772) for the HIR dichotomized at <0.4. The intraclass correlation coefficient (ICC) between HIR derived from VIZ AI compared to RAPID AI was 0.78 (95% CI 0.694-0.844).

Conclusions: In our sample of 107 cases, the level of agreement for the HIR derived from RAPID and VIZ dichotomized at <0.5 was in the moderate to very good range (Landis & Koch, 1977), versus in the moderate to good range when dichotomized at <0.4. Based on the ICC, agreement was in the moderate to good range. Further investigation of the agreement of HIR derived from RAPID AI and VIZ AI should be conducted before applying HIR thresholds derived from RAPID AI to CTP studies analyzed by VIZ AI to predict favorable collateralization.

Cerebral blood volume index as a predictor of functional independence after basilar artery thrombectomy

BACKGROUND AND PURPOSE

The role of CT perfusion (CTP)in the evaluation of acute basilar artery occlusion (aBAO) patients undergoing endovascular thrombectomy (EVT) is unclear. We investigated the association of individual CTP parameters with functional outcomes in aBAO patients undergoing EVT.

METHODS

A health system's prospectively collected code stroke registry was used in this retrospective analysis of aBAO patients treated with EVT presenting between January 2017 and February 2021 with pre-EVT CTP. The primary outcome measure was modified Rankin Scale (mRS) score 0-2 at 90 days. Factors with a univariate association (p < .05) with mRS 0-2 were combined in a multivariable regression model to determine independent predictors of 90-day favorable functional outcome.

RESULTS

Forty-six subjects, with median age 67 years and median National Institutes of Health Stroke Scale 16, were included, of whom 17 (37%) achieved mRS 0-2 at 90 days. In the multivariable logistic regression model, CTP cerebral blood volume (CBV) index (per 0.1-point increase, odds ratio = 1.843; 95% confidence interval: 1.039, 3.268; p-value .0365) was independently associated with a favorable 90-day outcome.

CONCLUSIONS

CBV index was independently associated with a favorable 90-day outcome in aBAO patients treated with EVT, a novel finding in this patient population. CBV index may assist in treatment and prognosis discussions and inform future studies investigating the role of CTP in aBAO.

Mortality after large artery occlusion acute ischemic stroke

Despite randomized trials showing a functional outcome benefit in favor of endovascular therapy (EVT), large artery occlusion acute ischemic stroke is associated with high mortality. We performed a retrospective analysis from a prospectively collected code stroke registry and included patients presenting between November 2016 and April 2019 with internal carotid artery and/or proximal middle cerebral artery occlusions. Ninety-day mortality status from registry follow-up was corroborated with the Social Security Death Index. A multivariable logistic regression model was fitted to determine demographic and clinical characteristics associated with 90-day mortality. Among 764 patients, mortality rate was 26%. Increasing age (per 10 years, OR 1.48, 95% CI 1.25–1.76; p < 0.0001), higher presenting NIHSS (per 1 point, OR 1.05, 95% CI 1.01–1.09, p = 0.01), and higher discharge modified Rankin Score (per 1 point, OR 4.27, 95% CI 3.25–5.59, p < 0.0001) were independently associated with higher odds of mortality. Good revascularization therapy, compared to no EVT, was independently associated with a survival benefit (OR 0.61, 95% CI 0.35–1.00, p = 0.048). We identified factors independently associated with mortality in a highly lethal form of stroke which can be used in clinical decision-making, prognostication, and in planning future studies.

Abstract P361: Visualization of the Anterior Temporal Artery as a Predictor of Outcome in Middle Cerebral Artery Occlusion Patients Achieving Successful Recanalization After Interfacility Transfer

Introduction: Many non-thrombectomy centers lack Computerized Tomography Perfusion (CTP) capability. Anterior temporal artery (ATA) visualization on Computerized Tomography Angiography (CTA) has been previously associated with good outcomes in middle cerebral artery (MCA) occlusions, but not in the context of recanalization after interfacility transfer for thrombectomy. We hypothesized that independent functional outcome at 90 days would be greater for MCA occlusion patients initially presenting to non-thrombectomy centers with a visualized ATA on CTA who achieved TICI 2b or greater recanalization after transfer.

Methods: We conducted a retrospective cohort study of patients transferred for mechanical thrombectomy. A neuroradiologist blinded to patient outcomes confirmed the MCA as the most proximal site of occlusion on CTA, and assessed for visualization of the ATA. TICI 2b or greater revascularization scores were confirmed by neurointerventionalists blinded to patient outcomes. Ninety-day mRS scores were obtained via telephone utilizing a structured questionnaire.

Results: We identified a total of 107 MCA occlusion patients over a 3 ½ year period meeting our inclusion criteria. There were no significant differences in age, gender, race, comorbidities, median NIHSS, or time-to-revascularization variables between the ATA visualized (n=50) versus non-visualized (n=57) group, with the exception of significantly more wake-up strokes in the ATA visualized group (34.7% vs 16.1%, p=0.03). There was a non-significant trend for independent outcome (mRS ≤2) at 90 days for patients with ATA visualization compared to those for whom the ATA was not visualized on the CTA (63.8% vs 45.5%, p=0.06).

Conclusion: For MCA occlusion patients initially presenting to non-thrombectomy centers achieving successful recanalization via mechanical thrombectomy, there is a strong trend for visualization of the anterior temporal artery on the CTA performed at the non-thrombectomy center as being a predictor of independent functional outcome. Especially for institutions without CTP capability, this association with ATA visualization should be further investigated as a predictor for good outcome after transfer for successful mechanical thrombectomy.

Abstract P86: The Temporal Relationship of the First Reported Covid Case and Statewide Executive Orders to Regional Code Stroke Activation Trends During North Carolina’s First Covid Surge

Introduction: A decline in suspected acute stroke (“code stroke”) presentations in the United States (US) during the first COVID surge has been previously reported. While state emergency declarations may have contributed to the decline and rebound of weekly code stroke activations in our region, the exact temporal relationship of those declarations relative to weekly code stroke volumes is unclear.

Methods: We conducted an interrupted time series analysis (ITSA) to identify the impact of the first reported COVID case in North Carolina (NC) and subsequent statewide executive orders (SEOs) on weekly code stroke activation trends across our regional stroke network’s 20 facilities during a 33-week period (December 8, 2019 to July 25, 2020). We included the following time epochs: the first reported COVID case in NC, the NC SEO prohibiting mass gatherings and closing public schools, the stay-at-home NC SEO, and the NC phase 1 and phase 2 reentry orders, which eased restrictions.

Results: Utilizing our integrated healthcare network’s code stroke registry, we evaluated 3740 code stroke activations over a 33-week period. We performed two ITSA considering different starting points for the first intervention—one defined as the first COVID case and the other the first SEO. For both models the end of the first-time interval ended with the second SEO. Most of the downward trend in code stroke activation volume was temporally after the first COVID case (p=0.0029), not after the first SEO. After the second SEO, which increased social restrictions, there was a significant increased trend in code stroke activation volume (p=0.0047), while the phase 1 and 2 reopening SEOs were not associated with a significant increase in weekly code stroke activations.

Conclusion: Our data indicate that in our region, the decreased trend in code stroke activations preceded the first SEO and started temporally after the first reported COVID case in NC. The overall decrease in code stroke volume was not significantly associated with increasing statewide restrictions and lessening of those restrictions was not significantly associated with a rebounding trend. Restrictive and reentry SEOs do not explain changes in weekly code stroke activation trends our region experienced during its first COVID surge.

Abstract P557: Hypoperfusion Intensity Ratio and Cerebral Blood Volume Index as Predictors of Outcome for Recanalized Middle Cerebral Artery Occlusions

Introduction: Preliminary data suggest the Hypoperfusion Intensity Ratio (HIR) and the Cerebral Blood Volume Index (CBVI) derived from Computerized Tomography Perfusion (CTP) imaging predict the rate of collateral flow, speed of infarct growth, and clinical outcome. We hypothesized that functional outcomes at hospital discharge would be significantly better for middle cerebral artery (MCA) occlusion patients achieving Thrombolysis in Cerebral Infarction (TICI) 2b or greater recanalization with presenting hospital CTPs consistent with “good” (HIR <0.5 and CBVI >0.7) versus “poor” (HIR ≥0.5 and CBVI ≤0.7) indices.

Methods: We conducted a retrospective cohort study. A neuroradiologist confirmed the MCA occlusion based on the initial Computerized Tomography Angiogram (CTA). All TICI scores were confirmed by neurointerventionalists blinded to patient outcomes. We defined independent outcome as mRS ≤2, and favorable outcome as an mRS ≤3. We additionally stratified patients as initially presenting to thrombectomy versus non-thrombectomy centers.

Results: We identified a total of 162 patients over a 3 ½ year period with an MCA occlusion achieving TICI 2b recanalization or greater, of whom 67 had good indices and 48 had poor indices. For patients with good compared to poor indices, there was a trend for achieving independent outcome (55% vs 37%, p=0.061) that reached significance for favorable outcome (69% vs 50%, p=0.043). Limiting the analysis to only patients presenting to non-thrombectomy centers (n=67), these findings were consistent, with a trend for achieving independent outcome for good versus poor collaterals (48% vs 30% p=0.173), which was again significant for a favorable outcome (66% vs 39%, p=0.036). Across all patients, HIR <0.5 (n=86) or CBVI >0.7 (n=95) were not independently associated with independent outcomes, but for patients presenting to non-thrombectomy centers, an HIR <0.5 alone (n=51) was significantly associated with favorable outcome.

Conclusion: For MCA occlusion patients achieving TICI 2b recanalization, the combination of good HIR and CBVI is significantly associated with a favorable functional outcome. For patients presenting to non-thrombectomy centers, HIR alone may be sufficient to predict favorable outcome.

Case series demonstrating the value of computed tomography perfusion in differentiating ischemic strokes from seizures in patients with isolated aphasia

The value of computed tomography perfusion (CTP) imaging in suspected stroke patients who are not candidates for mechanical thrombectomy is promising. This case series demonstrates how CTP imaging aided in distinguishing seizure from stroke in 5 patients who presented to the emergency department with acute onset of isolated aphasia.

Age and discharge modified Rankin score are associated with 90-Day functional outcome after basilar artery occlusion treated with endovascular therapy

INTRODUCTION

Prognostic factors for functional outcome after basilar artery occlusion (BAO) treated with modern endovascular therapy (EVT) are sparse. We investigated the association between clinical characteristics, readily available imaging variables, and outcome in BAO patients treated with EVT.

METHODS

Retrospective analysis from a large healthcare system's prospectively collected code stroke registry of acute BAO patients treated with EVT between January 2017-January 2020. The primary outcome measure was a favorable 90-day modified Rankin score (mRS) of 0-2.

RESULTS

65 patients (median age 67 years, 57% male, median NIHSS 16) met the study inclusion criteria. Thrombolysis in Cerebral Infarction (TICI) 2 b-3 revascularization was achieved in 57/65 patients (88%) with a median time to revascularization of 445 minutes [IQR 302-840]. Ninety-day good outcome was seen in 35% (23/65) of patients. In a univariate analysis, age, history of ischemic stroke, baseline NIHSS, BAO site, and discharge mRS were associated with significant differences between the good and poor outcome groups. A multivariable logistic regression analysis demonstrated an independent association with 90-day good outcome and younger age (per 1-year, OR 0.79, 95% CI 0.64, 0.98) and good discharge mRS (0-2) (OR > 999.99, 95% CI 13.26, > 999.99).

CONCLUSIONS

Patients presenting with an acute BAO treated with modern EVT have a good 90-day outcome in over one-third of cases. Age and discharge mRS are independently associated with good 90-day outcome. Additional studies may focus on factors that can enhance discharge function after BAO, a novel prognostic indicator for favorable 90-day outcome in our study.

Test characteristics of a 5-element cortical screen for identifying anterior circulation large vessel occlusion ischemic strokes

OBJECTIVE

Stroke severity screens typically include cortical signs, such as field cut, aphasia, neglect, gaze preference, and dense hemiparesis (FANG-D). The accuracy and reliability of these signs, when assessed by emergency physicians, to identify patients with anterior circulation large vessel occlusion (ACLVO) acute ischemic stroke (AIS) is unknown. We hypothesized that the FANG-D screen applied by emergency physicians would be sensitive and reliable for identifying ACLVO AIS.

METHODS

We conducted a prospective cohort study enrolling consecutive patients with suspected AIS presenting within 4.5 hours of last known well to the emergency department (ED). Emergency physicians performed the FANG-D screen prior to, and blinded to the results of, imaging. The imaging standard was defined as a non-contrast computed tomography (CT) for identifying hemorrhage and CT angiography for identifying large vessel occlusion. ACLVO was defined as an occlusion of the internal carotid artery, the middle cerebral artery, or its first branch. A convenience sample of patients had a duplicate FANG-D screen performed by a second emergency physician to assess interobserver agreement.

RESULTS

We performed 608 FANG-D assessments on 491 patients presenting to the ED, of whom 64 (10%) had an ACLVO. FANG-D had a sensitivity of 91% (confidence interval [CI] = 81%-96%) and a specificity of 35% (CI = 31%-39%) for identifying ACLVO. Interobserver agreement was tested on 133 patients and was found to be substantial, with a Fleiss' kappa of 0.77 (CI = 0.64-0.88).

CONCLUSIONS

The FANG-D screen is a sensitive test for identifying ACLVO when performed by emergency physicians and demonstrates substantial interrater reliability.

Teaching Impact on Telestroke Nurse Recognition of Large Vessel Occlusion Computerized Tomography Perfusion Patterns

Background and Purpose—

A distinguishing feature of our Stroke Network is telestroke nurses who remotely facilitate evaluations. To enable expeditious transfer of large vessel occlusion (LVO) acute ischemic stroke patients presenting to nonthrombectomy centers, the telestroke nurses must immediately identify color thresholded computerized tomography perfusion (CTP) patterns consistent with internal carotid artery (ICA), middle cerebral artery (MCA) segment 1(M1), and MCA segment 2 (M2) LVO acute ischemic stroke.

Methods—

We developed a 6-month series of tutorials and tests for 16 telestroke nurses, focusing on CTP pattern recognition consistent with ICA, M1, or M2 LVO acute ischemic stroke. We simultaneously conducted a prospective cohort study to evaluate the impact of this intervention.

Results—

Telestroke nurses demonstrated good accuracy in detecting ICA, M1, or M2 LVO during the first 3 months of teaching (83%–94% accurate). This significantly improved during the last 3 months (99%–100%), during which the likelihood of correctly identifying the presence of any one of these LVOs exceeded that of the first 3 months ( P <0.001). There was a higher probability of correctly identifying any CTP pattern as consistent with either an ICA, M1, or M2 occlusion versus other types of occlusions or nonocclusions (odds ratio, 5.22 [95% CI, 3.2–8.5]). Over time, confidence for recognizing CTP patterns consistent with an ICA, M1, or M2 LVO did not differ significantly.

Conclusions—

A series of tutorials and tests significantly increased the likelihood of telestroke nurses correctly identifying CTP patterns consistent with ICA, M1, or M2 LVOs, with the benefit of these tutorials and test reviews peaking and plateauing at 4 months.

Assessment of Vessel Density on Non-Contrast Computed Tomography to Detect Basilar Artery Occlusion

Introduction

Basilar artery occlusion (BAO) may be clinically occult due to variable and non-specific symptomatology. We evaluated the qualitative and quantitative determination of a hyperdense basilar artery (HDBA) on non-contrast computed tomography (NCCT) brain for the diagnosis of BAO.

Methods

We conducted a case control study of patients with confirmed acute BAO vs a control group of suspected acute stroke patients without BAO. Two EM attending physicians, one third-year EM resident, and one medical student performed qualitative and quantitative assessments for the presence of a HDBA on axial NCCT images. Our primary outcome measures were sensitivity and specificity for BAO. Our secondary outcomes were inter-rater and intra-rater reliability of the qualitative and quantitative assessments.

Results

We included 60 BAO and 65 control patients in our analysis. Qualitative assessment of the hyperdense basilar artery sign was poorly sensitive (54%–72%) and specific (55%–89%). Quantitative measurement improved the specificity of hyperdense basilar artery assessment for diagnosing BAO, with a threshold of 61.0–63.8 Hounsfield units demonstrating relatively high specificity of 85%–94%. There was moderate inter-rater agreement for the qualitative assessment of HDBA (Fleiss’ kappa statistic 0.508, 95% confidence interval: 0.435–0.581). Agreement improved for quantitative assessments, but still fell in the moderate range (Shrout-Fleiss intraclass correlation coefficient: 0.635). Intra-rater reliability for the quantitative assessments of the two attending physician reviewers demonstrated substantial consistency.

Conclusion

Our results highlight the importance of carefully examining basilar artery density when interpreting the NCCT of patients with altered consciousness or other signs and symptoms concerning for an acute basilar artery occlusion. If the Hounsfield unit density of the basilar artery exceeds 61 Hounsfield units, BAO should be highly suspected.

Abstract 60: Impact of Monthly Testing and Tutorials on Accuracy and Confidence of Telestroke Nurse Recognition of Anterior Circulation Large Vessel Occlusion CT Perfusion Patterns

Introduction: A distinguishing feature of our Stroke Network is Telestroke (TS) nurses (RNs) who remotely facilitate TS evaluations. To facilitate expeditious transfer the TS RNs, need to immediately identify CT perfusion (CTP) studies demonstrating patterns consistent with internal carotid artery (ICA), middle cerebral artery (M1), and first branch of the M1 (M2) large vessel occlusion (LVO) acute ischemic strokes (AIS).

Methods: We developed a 6-month series of tutorials and tests (12 CTP scans/month) for 16 TS RNs to recognize CTP patterns consistent with ICA, M1 or M2 LVO AIS. We simultaneously conducted a prospective cohort study of these nurses on the impact of these tutorials and tests.

Results: TS nurses demonstrated good accuracy in detecting ICA, M1 or M2 LVO presence during the first three months of teaching (83-94% accurate).This improved to excellent during the last three months (99-100%), during which the likelihood of correctly identifying the presence of any one of these LVOs was greater than in the first three months (OR 1.99, 95% CI: 1.83-2.17, p<0.001). The probability of correctly identifying ICA or M1 occlusions was much higher than correctly identifying all other LVOs (OR 68, 95% CI: 45-102, p<0.001). The likelihood of being at a higher confidence level compared to lower confidence levels in identifying any LVOs as being ICA or M1 was higher than in identifying other LVOs (OR 2.14, 95% CI: 1.6-2.8, p<0.001), but over time confidence for determining LVO presence did not differ significantly after controlling for subject variation.

Conclusion: A series of structured tutorials significantly increased the odds of TS nurses correctly identifying anterior circulation LVOs, with the benefit of these tutorials and test reviews peaking and plateauing at four months. Participating in TS nurse tutorials was associated with high odds and confidence for correctly identifying LVOs as being ICA or M1.

Abstract TP84: Agreement Between Alberta Stroke Program Early Computed Tomography Score and Computed Tomography Perfusion in Patient Selection for Mechanical Thrombectomy After Large Vessel Occlusion Acute Ischemic Stroke

Introduction: CT ASPECTS and CT Perfusion (CTP) are used to select patients for mechanical thrombectomy, an evidence-based treatment for Large Vessel Occlusion (LVO) Acute Ischemic Stroke (AIS). However, discordant results between the two imaging modalities creates uncertainty with respect to the volume of ischemic and infarcted brain tissue, and thus whether to offer revascularization. We sought to investigate the agreement between CT ASPECTS and CTP in selecting patients for mechanical thrombectomy.

Hypothesis: CT ASPECTS determined by a neuro-radiologist demonstrates moderate agreement with CTP in selecting patients with anterior circulation, LVO AIS for mechanical thrombectomy.

Methods: Over a 7-month period beginning in January 2018, we conducted a retrospective analysis from a large healthcare system’s stroke network database comparing the agreement between favorable CT ASPECTS (defined as score ≥ 6) and favorable CTP. Favorable CTP was defined according to the inclusion criteria from EXTEND-IA, DEFUSE 3, and DAWN, in the 0-6 hour, 6-16 hour, and 6-24 hour time windows, respectively, for patients with ICA or proximal MCA occlusions.

Results: Cases were identified in the 0-24 hour window with an ICA or M1 occlusion, baseline CT ASPECTS calculated by a neuro-radiologist, and CTP. The overall raw agreement between CT ASPECTS and CTP for the 145 cases in the 0-6 hour window was 81%, and Cohen’s kappa (κ) was 0.17 (no agreement). In the 6-16 hour window, the overall raw agreement for 46 cases was 78% (κ = 0.38, minimal agreement). In the 6-24 hour window, the overall raw agreement for 58 cases was 53% (κ = 0.14, no agreement).

Conclusions: In both early and extended time windows, CT ASPECTS and CTP demonstrate minimal to no agreement beyond chance in patient selection for mechanical thrombectomy. Additional studies are required to determine the most appropriate imaging selection criteria to guide treatment decisions in patients with anterior circulation, LVO AIS.

Abstract TP484: Does Near Real Time Tracking of Treatment Process Performance via a Large-Scale Stroke Data Repository With Enhanced Data Visualization and Analytics Improve Treatment Times?

Introduction: To facilitate process improvement and outcomes tracking, our large, integrated healthcare system created an extensive database within REDCap which interfaces with Power BI (Microsoft). Monitored metrics include pre-hospital, Code Stroke process, advanced imaging, treatment, and outcome data fields. Data are entered via manual abstraction, but automated daily updates of the data visualization and analytics enables reviewing of individual case data and aggregate standardized reports within Power BI. The advanced visualization allows the stroke team to facilitate process improvement in near real time. Our team looked to analyze the statistical impact on stroke metrics after implementation of the real time data review process.

Methods: We dichotomized data into patients initially presenting to our Comprehensive Stroke Center (CSC), versus those transferred to our CSC for potential mechanical thrombectomy. We then compared data for the 5-months before and 5-months after implementation of our advanced analytics.

Results:

Conclusions: In patients that arrivied directly to our CSC, we saw a statistical difference in patients Last Known Well to Door, Door to IVtPA Bolus, Door to Groin Puncture, and a 2% increase in mRS of 0-2 without statistical difference. In patients that were transferred to our CSC, we saw no statistical differences in any measure, but an overall decrease in Door to Treatment times and a 10% increase in mRS of 0-2. The expansion of Code Stroke window to include patients within 24 hours happened shortly after the comparison group started, leading to a significant increase in Last Known Well to Door for patients presenting to our CSC.

Abstract WP48: Computed Tomography Perfusion Core Infarct Measurement Compared to Diffusion-Weighted Magnetic Resonance Imaging in Patients With Revascularization of Anterior Circulation, Large Artery Occlusions

Introduction: Automated CT Perfusion (CTP) technology offers the potential to distinguish irreversibly damaged tissue from “at-risk,” potentially salvageable tissue. Regional Cerebral Blood Flow (CBF) < 30% has been identified as a good predictor of infarct core on CTP. Randomized trials investigating mechanical thrombectomy for large artery occlusion (LAO) acute ischemic stroke (AIS) have excluded patients with large core infarcts. We investigated the relationship between infarct core, as predicted by CTP, compared to the gold standard of DWI MRI, after revascularization of a proximal, anterior circulation, LAO AIS.

Hypothesis: CBF < 30% overestimates core infarct size compared to DWI MRI in at least one-third of patients with occlusions of the internal carotid artery (ICA) or middle cerebral artery (MCA) M1 or M2 segments treated with endovascular therapy achieving thrombolysis in cerebral infarction (TICI) grade 2b or 3.

Methods: From a large healthcare system’s stroke network database, we conducted a retrospective analysis comparing infarct core (CBF < 30%; RAPID iSchemaView) and post-revascularization DWI MRI (ADC < 620cc; RAPID iSchemaView) in patients with ICA, M1, or M2 LAO AIS between November 2016 and June 2017 with TICI 2b or 3 reperfusion.

Results: Over an 8-month period, 25 cases were identified with pre-treatment CTP, post-intervention MRI, and TICI 2b/3 revascularization of an ICA, M1, or M2 occlusion. Mean age was 61.1 years old and median NIHSS was 16. Mean duration from last known well time to CTP and MRI was 4.2 and 27.1 hours, respectively. Sixteen patients were treated with IV TPA and endovascular intervention, while 9 underwent only endovascular intervention. Median time to revascularization was 5.6 hours. CTP overestimated infarct size compared to follow-up MRI in 9/25 (36%) cases by an average of 17.8cc. Pearson correlation coefficient between CTP core infarct size and MRI infarct size was non-significant (r = 0.17, p = 0.41).

Conclusions: Core infarct size may be overestimated by CTP in a substantial number of patients with revascularization of proximal, anterior circulation LAO AIS. Caution should be exercised when using core infarct estimation of CBF < 30% to exclude patients from endovascular therapy.

Abstract TP62: Computed Tomography Perfusion Infarct Measurement Compared to Diffusion-Weighted Magnetic Resonance Imaging in Patients Without Revascularization of Anterior Circulation, Large Artery Occlusions

Introduction: The CT Perfusion (CTP) parameter Time-Maximum greater than 6 seconds (Tm > 6s) represents delayed blood flow in critically hypoperfused brain tissue. Though Tm > 6s is expected to accurately represent infarct size in stroke patients who do not undergo revascularization, some brain tissue at risk may not progress to infarction and recover spontaneously (“benign oligemia”). We sought to investigate the relationship between Tm > 6s and the gold standard of final infarct volume on DWI MRI in patients with anterior circulation, large artery occlusion (LAO) acute ischemic stroke (AIS) who do not achieve reperfusion.

Hypothesis: Critically hypoperfused brain tissue, as represented by CTP Tm > 6s, overestimates final infarct volume on DWI MRI in at least 50% of patients with ICA or proximal MCA occlusions without angiographic revascularization.

Methods: From a large healthcare system’s stroke network database, we conducted a retrospective analysis comparing delayed perfusion volume (Tm > 6s; RAPID iSchemaView) on CTP and DWI MRI volume (ADC < 620cc; RAPID iSchemaView) in patients with ICA, M1, or M2 occlusions between November 2016 and June 2017 not treated with acute reperfusion therapy, or without angiographic revascularization (TICI 0).

Results: Over an 8-month period, 19 cases were identified with baseline CTP, follow-up MRI, and no reperfusion of an ICA, M1, or M2 occlusion. Mean age was 65.8 years old and median NIHSS was 8. Mean duration from last known well time to CTP and MRI was 4.4 and 22.8 hours, respectively. Three patients were treated with IV TPA and endovascular therapy, 4 received only endovascular therapy, and 12 did not receive IV TPA nor endovascular intervention. The Tm >6s volume was greater than follow-up DWI MRI volume in 13/19 (68%) cases by an average of 37.4cc.

Conclusions: Critically hypoperfused brain tissue on CTP, represented by Tm > 6s, may spontaneously recover in patients with proximal, LAO AIS. Establishing CTP parameters that delineate ischemic penumbra from benign oligemia will aid in identifying the volume of ischemic tissue truly at risk for infarction in LAO patients.

Abstract TMP64: Appropriateness of Hemorrhagic Stroke Destination Facilities in Severity-Based Triage Algorithms for Emergency Medical Services

Background: Severity-based prehospital stroke triage protocols aim to identify patients with large vessel occlusion (LVO) acute ischemic strokes (AIS) who should be transported directly to comprehensive stroke centers (CSCs). Whether or not hemorrhagic stroke patients should be included in the stroke population targeted for direct routing to CSCs is unclear. We hypothesized that a majority of patients with hemorrhagic strokes who were initially transported to the ED of non-CSCs would be immediately transferred to CSCs for admission.

Methods: We conducted a cross-sectional study of suspected stroke patients transported by our county’s EMS agency from December 2015 – October 2016. We categorized patient’s initial EMS destination facility as CSC or non-CSC, and determined if, after emergency department (ED) evaluation, patients were transferred to a CSC for admission. We determined acute stroke diagnoses from medical record review.

Results: Among 2,402 EMS patients screened for stroke, 777 (32%) had a diagnosis consistent with acute stroke, of whom 10.9% (n=85) had an intracranial hemorrhage (ICH) and 2.1% (n=16) had a subarachnoid hemorrhage (SAH). Among all stroke patients, 51% (95% CI 48-55%) were initially transported to a non-CSC, including 42% (95% CI 32-54%) of all ICH and 38% (95% CI 15-65%) of all SAH patients. Among the ICH and SAH patients initially evaluated at a non-CSCs, 86% (95% CI 71-95%) were transferred to a CSC for admission. N o SAH or ICH patients initially transported to a CSC were transferred to another facility for admission.

Conclusions: In our metropolitan region, most hemorrhagic stroke patients initially transported by EMS to non-CSCs are transferred to CSCs for admission after their ED evaluation. These data suggest that when determining acceptable rates of over- and under-triage in severity-based stroke triage algorithms for EMS, hemorrhagic stroke patients should be included, along with LVO AIS patients, in the population considered appropriate for initial transport to a CSC.

Abstract TMP71: Non-Enhanced Computed Tomography to Computed Tomography Angiogram Performance Times: Telestroke versus Bedside Neurologists

Introduction: The 2015 AHA/ASA Stroke Management Guidelines strongly recommend that if endovascular therapy is contemplated, a Computed Tomography Angiogram (CTA) be included in the initial imaging evaluation. Telestroke neurologists evaluating patients at Non-endovascular Stroke Centers (NESCs) are mostly focused on achieving quick door-to-needle (DTN) intravenous (IV) tPA times, not prompt CTA performance times to facilitate expeditious endovascular treatment for large vessel occlusion (LVO) acute ischemic stroke (AIS) patients.

Hypothesis: The Non-Enhanced Computed Tomography (NECT) to CTA time interval for LVO patients evaluated by telestroke neurologists at NESCs is significantly longer than for LVO patients initially evaluated at Endovascular Stroke Centers (ESCs).

Methods: From a large healthcare system’s stroke network database, we conducted a retrospective analysis comparing the NECT to CTA time performance interval for consecutive patients initially presenting to any one of 23 different hospitals or freestanding emergency departments who were identified as having an LVO AIS and met candidacy for ESC transfer.

Results: Over 7 months, we identified 71 LVO cases initially presenting to one of 21 NESCs covered by teleneurologists and 62 cases from one of 2 ESCs covered by bedside neurologists. After removing the outliers (>95th percentile for ESC cases and >90th percentile for NESC cases), we retained 64 cases from NESCs and 59 from ESCs for our analysis. NECT to CTA times were significantly longer at the NESCs than at the ESCs, with NECT to CTA means of 27.94 minutes (SD: 24.93, IQR: 41.5) for NESC cases versus 10 minutes (SD: 3.29, IQR:4) for ESC cases (Kolmogorov-Smirnov test asymptotic p-value 0.0001),

Conclusion: The NECT to CTA performance time interval for LVO AIS patients evaluated at NESCs by telestroke neurologists is significantly longer than for LVO AIS patients evaluated at ESCs. These data suggest that steps should be taken to ensure that NECT to CTA time intervals receive the same attention as DTN IV tPA times in assessing overall telestroke neurologist process performance.

Patient-centered outcomes: a qualitative exploration of patient experience with electroencephalograms in the Emergency Department

The primary objective of this qualitative project was to understand the experience of patients who had first-time seizures and who did, and did not, have electroencephalograms (EEGs) performed in the Emergency Department (ED) as part of their initial evaluation, so as to refine the diagnostic and therapeutic approach to these patients and transform the standard of care for first-time seizures by focusing on outcomes as defined by patient experiences and expectations. In this paper, we show that, regardless of the diagnostic and therapeutic approach patients are given in the ED, patients and caregivers trust that health care providers will perform the standard of care consistent with the current medical practice for first-time seizures. However, performing EEGs in the ED and initiating appropriate anticonvulsant therapy for those patients who are at high risk for future seizures addresses patient needs by offering patients a sense of security and control over their medical condition and expediting appropriate follow up care, as long as clearly stated written diagnostic, treatment, and referral instructions are provided upon discharge.

PLUMBER Study (Prevalence of Large Vessel Occlusion Strokes in Mecklenburg County Emergency Response)

BACKGROUND AND PURPOSE

The recently proposed American Heart Association/American Stroke Association EMS triage algorithm endorses routing patients with suspected large vessel occlusion (LVO) acute ischemic strokes directly to endovascular centers based on a stroke severity score. The predictive value of this algorithm for identifying LVO is dependent on the overall prevalence of LVO acute ischemic stroke in the EMS population screened for stroke, which has not been reported.

METHODS

We performed a cross-sectional study of patients transported by our county's EMS agency who were dispatched as a possible stroke or had a primary impression of stroke by paramedics. We determined the prevalence of LVO by reviewing medical record imaging reports based on a priori specified criteria.

RESULTS

We enrolled 2402 patients, of whom 777 (32.3%) had an acute stroke-related diagnosis. Among 485 patients with acute ischemic stroke, 24.1% (n=117) had an LVO, which represented only 4.87% (95% confidence interval, 4.05%-5.81%) of the total EMS population screened for stroke.

CONCLUSIONS

Overall, the prevalence of LVO acute ischemic stroke in our EMS population screened for stroke was low. This is an important consideration for any EMS stroke severity-based triage protocol and should be considered in predicting the rates of overtriage to endovascular stroke centers.

Regional Evaluation of the Severity-Based Stroke Triage Algorithm for Emergency Medical Services Using Discrete Event Simulation

BACKGROUND AND PURPOSE

The Severity-Based Stroke Triage Algorithm for Emergency Medical Services endorses routing patients with suspected large vessel occlusion acute ischemic strokes directly to endovascular stroke centers (ESCs). We sought to evaluate different specifications of this algorithm within a region.

METHODS

We developed a discrete event simulation environment to model patients with suspected stroke transported according to algorithm specifications, which varied by stroke severity screen and permissible additional transport time for routing patients to ESCs. We simulated King County, Washington, and Mecklenburg County, North Carolina, distributing patients geographically into census tracts. Transport time to the nearest hospital and ESC was estimated using traffic-based travel times. We assessed undertriage, overtriage, transport time, and the number-needed-to-route, defined as the number of patients enduring additional transport to route one large vessel occlusion patient to an ESC.

RESULTS

Undertriage was higher and overtriage was lower in King County compared with Mecklenburg County for each specification. Overtriage variation was primarily driven by screen (eg, 13%-55% in Mecklenburg County and 10%-40% in King County). Transportation time specifications beyond 20 minutes increased overtriage and decreased undertriage in King County but not Mecklenburg County. A low- versus high-specificity screen routed 3.7× more patients to ESCs. Emergency medical services spent nearly twice the time routing patients to ESCs in King County compared with Mecklenburg County.

CONCLUSIONS

Our results demonstrate how discrete event simulation can facilitate informed decision making to optimize emergency medical services stroke severity-based triage algorithms. This is the first step toward developing a mature simulation to predict patient outcomes.

Abstract TP240: The PLUMBER (Prevalence of Large Vessel Occlusion Stroke in Mecklenburg County Emergency Response) Study

Introduction: Regional Emergency Medical System (EMS) protocols for acute stroke endorse routing patients with possible large vessel occlusion (LVO) acute ischemic strokes (AIS) directly to endovascular centers. These routing algorithms include prehospital stroke severity screens (PSSS) to determine the likelihood of an LVO AIS. An essential, but unreported, determinant of the predictive value of PSSS tools is the prevalence of LVO AIS stroke in the EMS population screened for stroke.

Hypothesis: Among EMS patients transported to Mecklenburg county hospitals screened for stroke, acute LVO AIS prevalence ranges from 5-10%.

Methods: We are conducting a prospective, observational study of all patients transported by the Mecklenburg county EMS agency who are either (1) dispatched as a possible stroke and/or (2) with a primary impression of stroke recorded by prehospital providers. We are reviewing medical records and neurovascular imaging studies to determine an acute LVO AIS diagnosis and the site(s) of occlusion.

Results: Thus far, over a six-month period we have enrolled 1441 patients, of whom 33% (n=480) had a diagnosis consistent with acute stroke (ischemic stroke, hemorrhagic stroke, or transient ischemic attack), with 20% (n=287) being an AIS. Eighty-eight percent (n=253) of AIS patients underwent an intracranial CTA or MRA. The prevalence of LVO stroke in the EMS population enrolled was 5.7% (n= 82, 95% CI 4.6-7.0%), with the most common vessel occluded being M1 (n=46, 56% of LVO AIS). The prevalence of LVO AIS in patients dispatched as a possible stroke was 4.8% (n =56; 95% CI 3.6-6.1%), while the prevalence in patients with a primary impression of stroke was 10% (n=74; 95% CI 8.2-13%).

Conclusions: Among patients screened for stroke by our county’s EMS agency, the prevalence of LVO AIS is low. This low LVO AIS prevalence, combined with a PSSS tool with modest accuracy, will yield poor predictive value for LVO AIS in an EMS population, resulting in a substantial rate of over-triage of non-LVO patients to endovascular centers. Data collection is ongoing to determine the accuracy of a prehospital stroke screen in identifying LVO AIS patients.

A geographic information system analysis of the impact of a statewide acute stroke emergency medical services routing protocol on community hospital bypass

BACKGROUND

Our goal was to determine if a statewide Emergency Medical Services (EMSs) Stroke Triage and Destination Plan (STDP), specifying bypass of hospitals unable to routinely treat stroke patients with thrombolytics (community hospitals), changed bypass frequency of those hospitals.

METHODS

Using a statewide EMS database, we identified stroke patients eligible for community hospital bypass and compared bypass frequency 1-year before and after STDP implementation.

RESULTS

Symptom onset time was missing for 48% of pre-STDP (n = 2385) and 29% of post-STDP (n = 1612) cases. Of the remaining cases with geocodable scene addresses, 58% (1301) in the pre-STDP group and 61% (2,078) in the post-STDP group were ineligible for bypass, because a community hospital was not the closest hospital to the stroke event location. Because of missing data records for some EMS agencies in 1 or both study periods, we included EMS agencies from only 49 of 100 North Carolina counties in our analysis. Additionally, we found conflicting hospital classifications by different EMS agencies for 35% of all hospitals (n = 38 of 108). Given these limitations, we found similar community hospital bypass rates before and after STDP implementation (64%, n = 332 of 520 vs. 63%, n = 345 of 552; P = .65).

CONCLUSIONS

Missing symptom duration time and data records in our state's EMS data system, along with conflicting hospital classifications between EMS agencies limit the ability to study statewide stroke routing protocols. Bypass policies may apply to a minority of patients because a community hospital is not the closest hospital to most stroke events. Given these limitations, we found no difference in community hospital bypass rates after implementation of the STDP.

Early stroke risk and ABCD2 score performance in tissue- vs time-defined TIA: a multicenter study

OBJECTIVES

Stroke risk immediately after TIA defined by time-based criteria is high, and prognostic scores (ABCD2 and ABCD3-I) have been developed to assist management. The American Stroke Association has proposed changing the criteria for the distinction between TIA and stroke from time-based to tissue-based. Research using these definitions is lacking. In a multicenter observational cohort study, we have investigated prognosis and performance of the ABCD2 score in TIA, subcategorized as tissue-positive or tissue-negative on diffusion-weighted imaging (DWI) or CT imaging according to the newly proposed criteria.

METHODS

Twelve centers provided data on ABCD2 scores, DWI or CT brain imaging, and follow-up in cohorts of patients with TIA diagnosed by time-based criteria. Stroke rates at 7 and 90 days were studied in relation to tissue-positive or tissue-negative subcategorization, according to the presence or absence of brain infarction. The predictive power of the ABCD2 score was determined using area under receiver operator characteristic curve (AUC) analyses.

RESULTS

A total of 4,574 patients were included. Among DWI patients (n = 3,206), recurrent stroke rates at 7 days were 7.1%(95% confidence interval 5.5-9.1) after tissue-positive and 0.4% (0.2-0.7) after tissue-negative events (p diff < 0.0001). Corresponding rates in CT-imaged patients were 12.8% (9.3-17.4) and 3.0% (2.0-4.2), respectively (p diff < 0.0001). The ABCD2 score had predictive value in tissue-positive and tissue-negative events (AUC = 0.68 [95% confidence interval 0.63-0.73] and 0.73 [0.67-0.80], respectively; p sig < 0.0001 for both results, p diff = 0.17). Tissue-positive events with low ABCD2 scores and tissue-negative events with high ABCD2 scores had similar stroke risks, especially after a 90-day follow-up.

CONCLUSIONS

Our findings support the concept of a tissue-based definition of TIA and stroke, at least on prognostic grounds.

Geographic and sociodemographic disparities in drive times to Joint Commission-certified primary stroke centers in North Carolina, South Carolina, and Georgia

INTRODUCTION

Timely access to facilities that provide acute stroke care is necessary to reduce disabilities and death from stroke. We examined geographic and sociodemographic disparities in drive times to Joint Commission-certified primary stroke centers (JCPSCs) and other hospitals with stroke care quality improvement initiatives in North Carolina, South Carolina, and Georgia.

METHODS

We defined boundaries for 30- and 60-minute drive-time areas to JCPSCs and other hospitals  by  using geographic information systems (GIS) mapping technology and calculated the proportions of the population living in these drive-time areas by sociodemographic characteristics. Age-adjusted county-level stroke death rates were overlaid onto the drive-time areas.

RESULTS

Approximately 55% of the population lived within a 30-minute drive time to a JCPSC; 77% lived within a 60-minute drive time. Disparities in percentage of the population within 30-minute drive times were found by race/ethnicity, education, income, and urban/rural status; the disparity was largest between urban areas (70% lived within 30-minute drive time) and rural areas (26%). The rural coastal plains had the largest concentration of counties with high stroke death rates and the fewest JCPSCs.

CONCLUSION

Many areas in this tri-state region lack timely access to JCPSCs. Alternative strategies are needed to expand provision of quality acute stroke care in this region. GIS modeling is valuable for examining and strategically planning the distribution of hospitals providing acute stroke care.

A link to improve stroke patient care: a successful linkage between a statewide emergency medical services data system and a stroke registry

OBJECTIVES

regionalization of stroke care, including diversion to stroke centers, requires that emergency medical services (EMS) systems accurately identify acute stroke patients. A barrier to evaluating and improving EMS stroke patient identification is the inability to link EMS data with hospital data for individual patients. We sought to create and validate a linkage of the North Carolina EMS Data System (NC-EMS-DS) with data contained in the North Carolina Stroke Care Collaborative (NCSCC) Registry.

METHODS

all NCSCC Registry patients arriving to one of three hospitals by EMS in a 6-month period were matched against NC-EMS-DS. Records were deterministically matched on receiving hospital, hospital arrival date/time, age, and sex. We performed linkage validation by providing each site investigator with a stroke patient list derived from North Carolina Stroke Care Collaborative Registry (NC-EMS-DS), matched by individual patient to deidentified data in the NCSCCR. Each site investigator determined the set of true matches by comparing the matched list to a NCSCCR patient identifier key maintained at each site. Incorrect matches were reviewed by the research team to identify methods for future improvement in the matching logic.

RESULTS

for the three validation hospitals, 753 NCSCC Registry patients arrived by EMS. For these patients, 473 (63%) matches to local EMS records were identified, and 421 (89%) of the matches were verified using full patient identifiers. Most match verification failures were due to incorrect date/time stamp and inability to find a corresponding EMS record.

CONCLUSIONS

linking EMS records electronically to a stroke registry is feasible and leads to a large number of valid matches. This small validation is limited by EMS data quality. Matching may improve with better EMS documentation and standardized facility documentation.

Drive-time proximity to Joint Commission Primary Stroke Centers among North Carolina residents who died of stroke

OBJECTIVE

In developing a statewide system of stroke care, understanding the relative availability of acute stroke care at designated centers for stroke care is essential. In this article, we compare the change in availability of acute stroke care in North Carolina at Joint Commission Primary Stroke Centers (JCPSCs) between 2006 and 2008 by examining the drive-time proximity of the residential address to the nearest JCPSC among people who died of stroke.

METHODS

We assigned geographic coordinates to residential addresses of North Carolinians who died of stroke and to addresses of North Carolina JCPSCs. We calculated the distance within a 40-minute drive from each JCPSC and determined whether the residential addresses of patients who died of stroke were in the areas demarcated by the drive time. In a secondary analysis, we included non-ICPSCs that participate in recognized quality-improvement programs for stroke care.

RESULTS

In 2006, 37% of geocodable residences of patients who died of stroke (3,834 of 10,469) were within a 40-minute drive from a JCPSC. By the end of 2008, this percentage increased to 56% (3,482 of 6,204). Inclusion of other hospitals that participate in recognized quality-improvement programs for acute stroke care increased the 40-minute drive-time coverage to 82% (5,095 of 6,204).

LIMITATIONS

As an index of the geographic distribution of the stroke burden, we used deaths due to stroke, rather incident strokes. We included several assumptions in our drive-time calculation.

CONCLUSIONS

For many regions of North Carolina in which the stroke burden is high, timely care at JCPSCs for acute stroke is unavailable. To develop a statewide system for acute stroke care in North Carolina, criteria beyond JCPSC certification should be considered for designating hospitals as centers for stroke care.

Early Diffusion Weighted MRI as a Negative Predictor for Disabling Stroke After ABCD 2 Score Risk Categorization in Transient Ischemic Attack Patients

Background and Purpose— The prognostic value early diffusion-weighted magnetic resonance imaging (DWMRI) adds in the setting of transient ischemic attack (TIA), after risk stratification by a clinical score, is unclear. The purpose of this study is to evaluate, after ABCD 2 score risk categorization in admitted TIA patients, whether negative DWMRI performed within 24 hours of symptom onset improves on the identification of patients at low risk for experiencing a disabling stroke within 90 days.

Methods— At 15 North Carolina hospitals, we enrolled a prospective nonconsecutive sample of admitted TIA patients. We excluded patients not undergoing a DWMRI within 24 hours of admission and patients for whom a dichotomized (≤ or >3) ABCD 2 score could not be calculated. We conducted a medical record review to determine disabling ischemic stroke outcomes within 90 days.

Results— Over 35 months, 944 TIA patients met inclusion criteria, of whom 4% (n=41) had a disabling ischemic stroke within 90 days. In analyses stratified by low versus moderate/high ABCD 2 score, the combination of a low risk ABCD 2 score and a negative early DWMRI had excellent sensitivity (100%, 95% CI 34 to 100) for identifying low-risk patients. In patients classified as moderate to high risk, a negative early DWMRI predicted a low risk of disabling ischemic stroke within 90 days (sensitivity 92%, 95% CI 80 to 97; NLR 0.11, 95% CI 0.04 to 0.32).

Conclusions— After risk stratification by the ABCD 2 score, early DWMRI enhances the prediction of a low risk for disabling ischemic stroke within 90 days. Further study is warranted in a large, consecutive TIA population of early DWMRI as a sensitive negative predictor for disabling stroke within 90 days.