A Randomized, Placebo-Controlled, Phase II Trial of Intravenous Allogeneic Non-HLA Matched, Unrelated Donor, Cord Blood Infusion for Ischemic Stroke

Stroke remains a leading cause of death and disability in the US, and time-limited reperfusion strategies remain the only approved treatment options. To address this unmet clinical need, we conducted a phase II randomized clinical trial to determine whether intravenous infusion of banked, non-HLA matched unrelated donor umbilical cord blood (UCB) improved functional outcome after stroke. Participants were randomized 2:1 to UCB or placebo within strata of National Institutes of Health Stroke Scale Score (NIHSS) and study center. Study product was infused 3-10 days following index stroke. The primary endpoint was change in modified Rankin Scale (mRS) from baseline to day 90. Key secondary outcomes included functional independence, NIHSS, the Barthel Index, and assessment of adverse events. The trial was terminated early due to slow accrual and logistical concerns associated with the COVID-19 pandemic, and a total of 73 of a planned 100 participants were included in primary analyses. The median (range) of the change in mRS was 1 point (-2, 3) in UCB and 1 point (-1,4) in Placebo (P = 0.72). A shift analysis comparing the mRS at day 90 utilizing proportional odds modeling showed a common odds ratio of 0.9 (95% CI: 0.4, 2.3) after adjustment for baseline NIHSS and randomization strata. The distribution of adverse events was similar between arms. Although this study did not suggest any safety concerns related to UCB in ischemic stroke, we did not show a clinical benefit in the reduced sample size evaluated.

Robot-Assisted Transcranial Doppler Versus Transthoracic Echocardiography for Right to Left Shunt Detection

BACKGROUND

Right to left shunt (RLS), including patent foramen ovale, is a recognized risk factor for stroke. RLS/patent foramen ovale diagnosis is made by transthoracic echocardiography (TTE), which is insensitive, transesophageal echocardiography, which is invasive, and transcranial Doppler (TCD), which is noninvasive and accurate but scarce.

METHODS

We conducted a prospective, single-arm device clinical trial of robot-assisted TCD (raTCD) versus TTE for RLS diagnosis at 6 clinical sites in patients who presented with an event suspicious for embolic cerebrovascular ischemia from October 6, 2020 to October 20, 2021. raTCD was performed with standard TCD bubble study technique. TTE bubble study was performed per local standards. The primary outcome was rate of RLS detection by raTCD versus TTE.

RESULTS

A total of 154 patients were enrolled, 129 evaluable (intent to scan) and 121 subjects had complete data per protocol. In the intent to scan cohort, mean age was 60±15 years, 47% were women, and all qualifying events were diagnosed as ischemic stroke or transient ischemic attack. raTCD was positive for RLS in 82 subjects (64%) and TTE was positive in 26 (20%; absolute difference 43.4% [95% CI, 35.2%-52.0%]; P<0.001). On prespecified secondary analysis, large RLS was detected by raTCD in 35 subjects (27%) versus 13 (10%) by TTE (absolute difference 17.0% [95% CI, 11.5%-24.5%]; P<0.001). There were no serious adverse events.

CONCLUSIONS

raTCD was safe and ≈3 times more likely to diagnose RLS than TTE. TTE completely missed or underdiagnosed two thirds of large shunts diagnosed by raTCD. The raTCD device, used by health professionals with no prior TCD training, may allow providers to achieve the known sensitivity of TCD for RLS and patent foramen ovale detection without the need for an experienced operator to perform the test. Pending confirmatory studies, TCD appears to be the superior screen for RLS compared with TTE (funded by NeuraSignal).

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04604015.

Reliability of the National Institutes of Health (NIH) Stroke Scale Between Emergency Room and Neurology Physicians for Initial Stroke Severity Scoring

INTRODUCTION

In patients with acute ischemic stroke (AIS), the National Institutes of Health Stroke Scale (NIHSS) is essential to establishing a patient's initial stroke severity. While previous research has validated NIHSS scoring reliability between neurologists and other clinicians, it has not specifically evaluated NIHSS scoring reliability between emergency room (ER) and neurology physicians within the same clinical scenario and timeframe in a large cohort of patients. This study specifically addresses the key question: does an ER physician's NIHSS score agree with the neurologist's NIHSS score in the same patient at the same time in a real-world context?

METHODS

Data was retrospectively collected from 1,946 patients being evaluated for AIS at Houston Methodist Hospital from 05/2016 - 04/2018. Triage NIHSS scores assessed by both the ER and neurology providers within one hour of each other under the same clinical context were evaluated for comparison. Ultimately, 129 patients were included in the analysis. All providers in this study were NIHSS rater-certified.

RESULTS

The distribution of the NIHSS score differences (ER score - neurology score) had a mean of -0.46 and a standard deviation of 2.11. The score difference between provider teams ranged ±5 points. The intraclass correlation coefficient (ICC) for the NIHSS scores between the ER and neurology teams was 0.95 (95% CI, 0.93 - 0.97) with an F-test of 42.41 and a p-value of 4.43E-69. Overall reliability was excellent between the ER and neurology teams.

CONCLUSION

We evaluated triage NIHSS scores performed by ER and neurology providers under matching time and treatment conditions and found excellent interrater reliability. The excellent score agreement has important implications for treatment decision-making during patient handoff and further in stroke modeling, prediction, and clinical trial registries where missing NIHSS scores may be equivalently substituted from either provider team.

Abstract WP129: Sociodemographic, Clinical, And Outcomes Characteristics Of Young Adult Patients With Intracerebral Hemorrhage

Intro: Incidence of intracerebral hemorrhage (ICH) in the young is increasing but risk factors and outcomes are not well characterized.

Methods: Using a stroke-specific bioinformatics pipeline across a 7-hospital certified stroke healthcare system, we identified adult non-traumatic ICH cases between 05/16 and 08/22 and flagged young ICH patients (YIP) aged 18 – 45. We compared sociodemographic, comorbidity, clinical, imaging, and treatment characteristics, and outcomes between YIP and non-YIP using logistic regression.

Results: Among 1 869 ICH patients, 187 (10%) were YIP. YIP (vs. Non-YIP) were predominantly privately insured (71.1 % vs. 29.8 %), non-Hispanic Black (33.7% vs. 22.2%), Hispanic (26.7% vs. 21.7%), and single (41.2% vs. 20.5%). A higher proportion of YIP were obese and a lower proportion had pre-existing comorbidities (Figure). A lower proportion of YIP were on statins, antiplatelets, or anticoagulants prior to ICH. A significantly smaller proportion of YIP had large hemorrhage volumes (> 30 ml) and experienced lower rates of in-hospital complications such as delirium and SIRS. A significantly greater proportion of YIP underwent craniotomy and had longer lengths of stay. After adjusting for important clinical and sociodemographic correlates of in-hospital mortality, YIP had a 59% lower likelihood of in-hospital mortality or hospice discharge OR (CI): 0.41 (0.20 – 0.82). Additionally, for outcome assessment, YIP were more likely to be contacted [2.9 (1.26, 8.08)], consented [3.7 (1.8, 7.8)], and complete follow-up survey [1.9 (1.0, 3.8)] than non-YIP. Though 50.5% of YIP had a 90-day mRS >3, there was a 51% lower likelihood of severe disability or death in YIP vs. non-YIP.

Conclusion: YIP poses a high morbidity burden and understanding long-term functional and cognitive outcomes is important. High follow-up rates provide an opportunity for engaging this often overlooked and underrepresented cohort of critically ill patients in future research.

Abstract WP6: Strokes Averted by Intravenous Thrombolysis: A Secondary Analysis of the BEST-MSU Trial

Introduction: While the goal of IV tissue plasminogen activator (TPA) is to prevent infarction, few data exist on averted stroke.

Methods: Secondary analysis of a multicenter trial from 2014-2020 comparing outcomes between patients treated for stroke by mobile stroke unit (MSU) vs standard care (SC). The analytical cohort were patients with suspected stroke treated with IV TPA. The primary outcome was a time-defined averted stroke diagnosis, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours. The secondary outcome was a tissue-defined averted stroke diagnosis, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours and no acute infarction/hemorrhage on imaging. We used multivariable logistic regression to evaluate associations between study exposures (demographics, comorbidities, stroke characteristics) and outcomes.

Results: Among 1009 patients with a median last known well-to-TPA time of 87 minutes, 276 patients (27%) had a time-defined averted stroke (31% MSU, 21% SC) and 159 patients (16%) had a tissue-defined averted stroke (18% MSU, 11% SC). Factors independently associated with time-defined averted stroke were younger age (OR, 0.98; 95% CI, 0.96-0.99), female sex (0R, 0.51; 95% CI, 0.36-0.74), hyperlipidemia (OR, 1.81, 95% CI, 1.24-2.64), normal premorbid function (0R, 2.22; 95% CI, 1.37-3.67), lower glucose (OR, 0.996; 95% CI, 0.993-0.999), lower MAP (OR, 0.991; 95% CI, 0.983-0.998), MSU care (OR, 1.77; 95% CI, 1.21-2.62), lower NIH stroke scale (OR, 0.89; 95% CI, 0.86-0.93), and no large vessel occlusion (LVO) (OR, 0.52; 95% CI, 0.32-0.83). For tissue-based averted stroke, younger age, female sex, hyperlipidemia, lower MAP, MSU treatment, lower NIH stroke scale, and no LVO were significantly associated.

Conclusion: In a modern acute stroke trial, one-in-four patients treated with TPA for stroke recovered within 24 hours and one-in-six had no demonstrable brain injury on imaging. Younger age, female sex, hyperlipidemia, lower MAP, MSU care, lower stroke severity, and no LVO may increase the odds of averting stroke.

Abstract WMP2: Acute Stroke Treatment In Patients With Pre-exiting Disability: A Secondary Analysis Of The BEST-MSU Trial

Background: Few data exists on acute stroke treatment in patients with pre-existing disability (PD) since they are usually excluded from clinical trials.

Methods: A pre-specified subgroup analysis of tPA-eligible patients with PD enrolled in a prospective multicenter trial of Mobile Stroke Units (MSUs) vs standard management by emergency medical services (EMS). All patients had baseline mRS scores. Co-primary outcomes were mean utility-weighted modified Rankin Scale score (uw-mRS) and return to baseline mRS at 90 days. Linear and logistic regression models compared outcomes in patients with vs without PD, and patients with PD treated by MSU vs EMS. Time metrics, safety, quality of life, and health-care utilization were also compared.

Results: Of 1047 patients, 254 had baseline mRS >= 2 (159 MSU, 95 EMS; 31% mRS 2, 52% mRS 3, 17% mRS 4). Compared to patients without disability, patients with PD were older, had higher NIHSS, more comorbidities, less often lived at home, were treated slower, and had less thrombectomy. Patients with PD had worse 90-day uw-mRS (0.39 vs 0.80), higher mortality, more health-care utilization and worse quality of life than patients without PD. However, rates of symptomatic intracranial hemorrhage and final diagnoses of stroke mimics were similar between groups, and 52% of patients with PD returned to their baseline mRS. Patients with PD treated within the first hour had better 90-day uw-mRS than those treated later (0.48 vs 0.36, p=0.01). Comparing patients with PD treated by MSU vs EMS, time from last-known-well to tPA bolus was shorter (82 vs 111 min), and 24% vs 0% were treated in the first hour. Among patients with PD, MSU patients had non-significantly better 90-day uw-mRS (0.41 vs 0.35, p=0.09) and higher rate of returning to baseline mRS (56% vs 44%, p=0.09) than EMS patients. There was no interaction between either time to treatment (p=0.24) or MSU vs EMS group assignment (p= 0.42), 90-day uw-mRS, and PD vs no disability status.

Conclusion: Although outcomes after stroke are less favorable in patients with vs without PD, in a large, controlled trial, we found no interaction between baseline disability and the benefit of MSU treatment. Our data support the earliest treatment of acute stroke patients regardless of premorbid functional status.

Abstract TP94: Optimizing The Utilization Of Cardiac Computed Tomography Angiography Among Patients With Ischemic Stroke

Background: The current AHA guidelines recommend (class IIb) advanced cardiac imaging in embolic stroke of unknown source (ESUS). We aim to better characterize the role of cardiac CTA (cCTA) in the evaluation of stroke patients.

Method: A retrospective review of stroke patients at a comprehensive stroke center, who had cCTA between 12/2016 and 11/2020 was conducted using institutional registries. Ischemic stroke patients with ESUS, cryptogenic (with ESUS as a competing etiology) and cardio-embolic etiologies were included. Only cardioembolic etiologies in which a suspicion of intracardiac thrombus with either a known diagnosis of atrial fibrillation or presence of LVAD were included. Cases with TIA, large vessel disease, small vessel disease, dissection or hemodynamic etiologies were excluded. TTE and cCTA results from all cases were reviewed for remarkable findings, most notably intracardiac thrombus, and analyzed if a change in anti-thrombotic therapy was directly attributable to cCTA results.

Results: As per our criteria, 96 cases (Female 42.7%, Black 37.5%, Age mean: 63.7 years) were included, of whom 45 (46.9%) were ESUS, 21 (21.9%) were cryptogenic, and 30 (31.2%) were cardioembolic. cCTA revealed intracardiac thrombus in 5 (5.2%) cases, all with LA thrombus. Of these, 3 (60%) had escalation of anti-thrombotic therapy. Interestingly, in one patient who had both cMRI and cCTA imaging, the cMRI revealed an apical LV thrombus which was not detected on cCTA.

Conclusion: In this retrospective analysis of 96 select stroke cases, escalation of anti-thrombotic therapy from anti-platelets to full dose anti-coagulation was indicated in 3 patients (3.1%) with addition of cCTA. Compared to a similar cohort of patients from the same institutional registry using cMRI as the advanced cardiac imaging modality, cCTA did not reveal any LV thrombi and even missed a case of LV thrombus seen on cMRI suggesting lower sensitivity for cCTA to detect LV thrombus. Further analysis of data is in process to determine the subset of stroke patients who would benefit the most from cCTA.

Readmission in patients undergoing percutaneous patent foramen ovale closure in the United States

Current estimates suggest that a patent foramen ovale (PFO) may exist in up to 25% of the general population and is a potential risk factor for embolic, ischemic stroke. PFO closure complications include bleeding, need for procedure-related surgical intervention, pulmonary emboli, device malpositioning, new onset atrial arrhythmias, and transient atrioventricular block. Rates of PFO closure complications at a national level in the Unites States remain unknown. To address this, we performed a contemporary nationwide study using the 2016 and 2017 Nationwide Readmissions Database (NRD) to identify patterns of readmissions after percutaneous PFO closure. In conclusion, our study showed that following PFO closure, the most common complications were atrial fibrillation/atrial flutter followed by acute heart failure syndrome, supraventricular tachycardia and acute myocardial infarction.

Automatic Segmentation in Acute Ischemic Stroke: Prognostic Significance of Topological Stroke Volumes on Stroke Outcome

BACKGROUND

Stroke infarct volume predicts patient disability and has utility for clinical trial outcomes. Accurate infarct volume measurement requires manual segmentation of stroke boundaries in diffusion-weighted magnetic resonance imaging scans which is time-consuming and subject to variability. Automatic infarct segmentation should be robust to rotation and reflection; however, prior work has not encoded this property into deep learning architecture. Here, we use rotation-reflection equivariance and train a deep learning model to segment stroke volumes in a large cohort of well-characterized patients with acute ischemic stroke in different vascular territories.

METHODS

In this retrospective study, patients were selected from a stroke registry at Houston Methodist Hospital. Eight hundred seventy-five patients with acute ischemic stroke in any brain area who had magnetic resonance imaging with diffusion-weighted imaging were included for analysis and split 80/20 for training/testing. Infarct volumes were manually segmented by consensus of 3 independent clinical experts and cross-referenced against radiology reports. A rotation-reflection equivariant model was developed based on U-Net and grouped convolutions. Segmentation performance was evaluated using Dice score, precision, and recall. Ninety-day modified Rankin Scale outcome prediction was also evaluated using clinical variables and segmented stroke volumes in different brain regions.

RESULTS

Segmentation model Dice scores are 0.88 (95% CI, 0.87-0.89; training) and 0.85 (0.82-0.88; testing). The modified Rankin Scale outcome prediction AUC using stroke volume in 30 refined brain regions based upon modified Rankin Scale-relevance areas adjusted for clinical variables was 0.80 (0.76-0.83) with an accuracy of 0.75 (0.72-0.78).

CONCLUSIONS

We trained a deep learning model with encoded rotation-reflection equivariance to segment acute ischemic stroke lesions in diffusion- weighted imaging using a large data set from the Houston Methodist stroke center. The model achieved competitive performance in 175 well-balanced hold-out testing cases that include strokes from different vascular territories. Furthermore, the location specific stroke volume segmentations from the deep learning model combined with clinical factors demonstrated high AUC and accuracy for 90-day modified Rankin Scale in an outcome prediction model.

Abstract 92: Delirium In-hospital Leads To Poor Short And Long-term Outcomes Among Treated And Non-treated Patients With Acute Ischemic Stroke

Background: Delirium in-hospital (DIH) is common among the critically ill. However, DIH incidence and outcomes are not well characterized among ischemic stroke (IS) patients, particularly those treated with intravenous tissue plasminogen activator (tPA) and / or mechanical thrombectomy (MT).

Methods: Utilizing data from a healthcare system with standardized delirium screening protocols, DIH was determined by a positive 4AT / CAM-ICU screen or diagnosis codes. IS patients with tPA or MT were flagged and a subset with available 90-day modified Rankin Scale (mRS) were analyzed for shifts in mRS scores associated with DIH, via ordinal logistic regression models adjusted for age, stroke severity, tPA or MT, Charlson Comorbidity Index [CCI], prior stroke and sepsis / infections. Common odds ratios (OR) and 95% confidence intervals (CI) are reported.

Results: Between May 2016 and June 2021, IS was the primary discharge diagnosis in 12,415 encounters (10,878 unique patients). DIH was documented in 41.6% of IS encounters, compared to 20.0% of non-IS encounters. Stroke-DIH patients (vs no-DIH Stroke) were older (median: 75 vs 65 years), more frequently female (53.3% vs 48.7%), with higher comorbidity burden (median CCI: 7 vs 5), longer hospital stays (median: 6 vs 3 days), higher in-hospital mortality (3.1% vs 0.5%), and fewer home discharges (36.2% vs 75.2%). Among a sub-cohort of 2,785 IS patients with 90-day mRS, fully adjusted model indicated lower mRS (OR, CI: 0.48, 0.41-0.57) for those with tPA or MT, and worse outcomes for DIH patients (OR, CI: 2.70, 2.26-3.23). Among 948 treated IS patients, DIH remained a significant risk for worse outcomes (OR, CI: 2.54, 1.89-3.43).

Conclusion: Delirium was twice as common in IS patients and was a negative prognostic indicator of short and long-term outcomes among non-treated and treated IS patients. Active screening and management of DIH is critically important to improve stroke outcomes.

Abstract TP105: Optimizing The Utilization Of Cardiac Magnetic Resonance Imaging Among Patients With Ischemic Stroke

Background: The current AHA guidelines recommend (class IIb) advanced cardiac imaging in an embolic stroke of unknown source (ESUS). We aim to better characterize the role of cardiac MRI (cMRI) in the evaluation of stroke patients and determine patient characteristics that may increase the positive predictive value of cMRI.

Method: A retrospective review of stroke patients at a comprehensive stroke center, who had cMRI between 12/2016 and 11/2020 was conducted using institutional registries. Ischemic stroke patients with ESUS, cryptogenic (with ESUS as a competing etiology), and cardioembolic etiologies were included. Cases with TIA, large vessel, small vessel, or hemodynamic etiologies were excluded. Cardioembolic etiology was defined as newly diagnosed Afib patients with TTE abnormalities including wall motion abnormalities and/or reduced LVEF <50%, stroke while compliant with anticoagulation for known Afib, or among whom the timing of restarting anticoagulation was in question. TTE and cMRI results from all cases were reviewed for remarkable findings, most notably intracardiac thrombus, and analyzed if a change in anti-thrombotic therapy was directly attributable to cMRI results.

Results: As per our criteria, 250 cases (Female 44.4%, Black 29.6%, Age mean: 65.2 years) were included, of whom 146 (58.4%) were ESUS, 86 (34.4%) were cryptogenic, and 18 (7.2%) were cardioembolic. Sixteen (6.4%) revealed intracardiac thrombus, of which 10 had LV thrombus, 5 had LA thrombus, and 1 had RA thrombus along with questionable PFO on cMRI. Of these, 14 (87.5%) had an escalation of anti-thrombotic therapy. For the other 2 cases, despite cMRI obtained due to low LVEF and revealing LA thrombus, antithrombotic regimen was not changed. Eight (3.2%) additional patients were placed on anticoagulation secondary to incidental findings.

Conclusion: In this large retrospective analysis of 250 select stroke cases, escalation of anti-thrombotic therapy from anti-platelets to full dose anti-coagulation was indicated in 14 patients (5.6%) with addition of cMRI. Further analysis of data is in process to determine the subset of stroke patients who would benefit the most from cMRI.

Abstract 33: Stroke Severity Mediates The Association Between Socioeconomic Disadvantage And Poor Outcomes Among Patients With Acute Ischemic Stroke

Background: Impact of socioeconomic disadvantage on outcomes among acute ischemic stroke (AIS) patients has not been well characterized.

Methods: Clinical data on AIS patients were extracted from electronic medical records and 90-day modified Rankin Scale (mRS) scores were collected as a part of prospective stroke registry. Exact patient addresses were geocoded, and state-level Area Deprivation Index (ADI) ranks were categorized as low, medium, high. Patients with a 90-day mRS score ≥ 4 were categorized as severe disability or death (SDD). Logistic regression models (adjusted for treatment with intravenous tissue plasminogen activator or mechanical thrombectomy, age, sex, race/ethnicity, insurance, prior stroke, vascular risk factors) were fitted to compute odds ratios (OR) and 95% confidence intervals (CI) for total effect of high ADI on SDD. Structural equation modeling was used to assess mediation effects of stroke severity as measured by National Institutes of Health Stroke Scale (NIHSS).

Results: Between May 2016 and Apr 2021, a total of 2,900 AIS patients (mean age: 68.5 years; 50.1% male; 28.4% non-Hispanic Black; 12.9% Hispanic) with complete outcomes data were included. In an adjusted model, high ADI was significantly associated with SDD (OR, CI: 1.14, 1.02-1.28). In the mediation analysis, patients in higher ADI neighborhoods had a 28% increased likelihood of having higher NIHSS (OR: 1.28, CI: 1.15-1.44). Likewise, higher NIHSS was associated with SDD (OR: 7.10, CI: 5.96-8.51). The effect of neighborhood disadvantage on SDD was fully mediated by NIHSS (average causal mediation effect of ADI on SDD: P=0.002), with 77% of the total effect pathway mediated through NIHSS. The proportions of 90-day mRS by ADI categories are reported (Figure).

Conclusion: Neighborhood disadvantage leads to poor stroke outcomes mediated via stroke severity. Tracking social determinants of health may identify opportunities for reducing stroke related disability.

Abstract WP143: Stroke Severity Mediates The Association Between Neighborhood Socioeconomic Deprivation And Poor Outcomes Among Patients With Intracerebral Hemorrhage

Background: Relationships between neighborhood socioeconomic deprivation (NSD) and Intracerebral hemorrhage (ICH) outcomes are not well characterized. We sought to evaluate the impact of NSD on ICH outcomes and assessed mediating pathways for association between NSD and poor outcomes.

Methods: Clinical data were extracted from the electronic medical records and 90-day modified Rankin Scale (mRS) scores were obtained from a prospectively collected stroke registry at a large healthcare system. Presentation NIHSS score was used to assess ICH severity. Exact patient addresses were geocoded, and state-level Area Deprivation Index (ADI) was calculated, with high NSD (H-NSD) categorized as top 15% of ADI scores. The outcome was severe disability or death (SDD) (mRS ≥ 4). Age-adjusted logistic regression models were fitted, and mediation analyses were performed utilizing structured equation modeling. Odds ratios (OR) and 95% Confidence Intervals (CI) are reported.

Results: Final analyses included 486 patients with complete data (mean age: 65.6 years, 45.9 % female, 28.8% non-Hispanic Black, 20.2% Hispanic, median presentation NIHSS: 10, and median 90-day mRS 4). In separate age-adjusted models, both high NIHSS scores (OR, CI: 1.24, 1.20 - 1.29) and H-NSD (OR, CI: 1.59, 1.02 - 2.46) were associated with SDD. In a mediation analysis, H-NSD significantly contributed to higher NIHSS scores (OR, CI: 14.30, 1.44 - 141.61) and in turn higher NIHSS scores were significantly associated with SDD (OR, CI: 1.03, 1.03 - 1.04). In this analysis, H-NSD did not retain a significant direct effect on SDD (OR, CI: 1.38, 0.96 - 1.12) and was instead fully mediated by high NIHSS scores (Figure 1).

Discussion: Our analyses uniquely identify higher stroke severity as a potential causal pathway between NSD and poor ICH outcomes. These findings warrant comprehensive understanding of factors that may predispose the disadvantaged to experience higher ICH severity and greater neurological deficit.

Abstract WP140: Environment Matters: Neighborhood Socioeconomic Disadvantage And Cerebral Small Vessel Disease Are Associated With Poor Outcomes Among Patients With Intracerebral Hemorrhage

Background: Only 20-30% of Intracerebral Hemorrhage (ICH) survivors achieve functional independence. We investigated if neighborhood socioeconomic disadvantage (NSD) mediated by cerebral small vessel disease (CSVD) is associated with post-ICH functional outcomes.

Methods: Clinical and imaging data were extracted from electronic medical records and 90-day modified Rankin Score (mRS) was obtained from prospectively collected stroke registry at a large hospital system. CSVD was assessed based on MRI markers from 1-year before to 30 days after the ICH event and was scored from 0-4 with severe CSVD (S-CSVD) ≥ 2. Exact patient addresses were geocoded, and state-level Area Deprivation Index (ADI) was calculated, with high NSD (H-NSD) categorized as the top 15% of ADI scores. The outcome was severe disability or death (SDD) categorized as 90-day mRS score ≥4. Multivariate logistic regression models were fitted, and mediation was evaluated by structural equation modeling. Odds ratios (OR) and 95% confidence intervals (CI) are reported.

Results: Final analysis included 367 patients (mean age: 65 years, 49.7% female, median presentation ICH Score: 1) with complete data. We found significant associations between older age, Black race, S-CSVD, H-NSD, hematoma volume, presence of ventricular hemorrhage, presentation systolic blood pressure (SBP), and ICH score with SDD (P<0.05). In a multivariate model adjusted for age, SBP, ICH score and other important clinical co-variates, SDD was significantly and independently associated with both H-NSD (OR, CI: 2.03, 1.05 - 4.23) and S-CSVD (OR, CI: 1.93, 1.12 - 3.35). Our data did not demonstrate an association between CSVD and NSD; and S-CSVD did not mediate the relationship between H-NSD and SDD.

Discussion: In addition to known clinical factors, NSD, as measured by the ADI, and CSVD were independently associated with poor ICH outcomes. Potential causal pathways between H-NSD and poor ICH outcomes need to be further evaluated.

Retrospective study of deep learning to reduce noise in non-contrast head CT images

PURPOSE

Presented herein is a novel CT denoising method uses a skip residual encoder-decoder framework with group convolutions and a novel loss function to improve the subjective and objective image quality for improved disease detection in patients with acute ischemic stroke (AIS).

MATERIALS AND METHODS

In this retrospective study, confirmed AIS patients with full-dose NCCT head scans were randomly selected from a stroke registry between 2016 and 2020. 325 patients (67 ± 15 years, 176 men) were included. 18 patients each with 4-7 NCCTs performed within 5-day timeframe (83 total scans) were used for model training; 307 patients each with 1-4 NCCTs performed within 5-day timeframe (380 total scans) were used for hold-out testing. In the training group, a mean CT was created from the patient's co-registered scans for each input CT to train a rotation-reflection equivariant U-Net with skip and residual connections, as well as a group convolutional neural network (SRED-GCNN) using a custom loss function to remove image noise. Denoising performance was compared to the standard Block-matching and 3D filtering (BM3D) method and RED-CNN quantitatively and visually. Signal-to-noise ratio (SNR) and contrast-to-noise (CNR) were measured in manually drawn regions-of-interest in grey matter (GM), white matter (WM) and deep grey matter (DG). Visual comparison and impact on spatial resolution were assessed through phantom images.

RESULTS

SRED-GCNN reduced the original CT image noise significantly better than BM3D, with SNR improvements in GM, WM, and DG by 2.47x, 2.83x, and 2.64x respectively and CNR improvements in DG/WM and GM/WM by 2.30x and 2.16x respectively. Compared to the proposed SRED-GCNN, RED-CNN reduces noise effectively though the results are visibly blurred. Scans denoised by the SRED-GCNN are shown to be visually clearer with preserved anatomy.

CONCLUSION

The proposed SRED-GCNN model significantly reduces image noise and improves signal-to-noise and contrast-to-noise ratios in 380 unseen head NCCT cases.

Transcranial Doppler and magnetic resonance angiography assessment of intracranial stenosis: An analysis of screening modalities

BACKGROUND:

Time-of-flight (TOF) magnetic resonance angiography (MRA) of the head and transcranial Doppler (TCD) are used to diagnose intracranial stenosis, an important cause of ischemic stroke. We aimed to compare TCD findings with TOF-MRA results in a population of patients with symptoms of cerebrovascular disease in whom both tests were done within a short intervening period of each other.

METHODS:

This is a retrospective, single-center study. Among adult patients referred for symptoms of cerebrovascular disease in both outpatient and inpatient settings, those who received a TCD with adequate insonation of all intracranial arteries and underwent MRA within 3 months intervals of TCD were included in this study. We evaluated the agreement between the results of these two modalities, and also assessed sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of TCD through receiver-operating characteristic (ROC) curve analysis, while MRA considered as a comparator.

RESULTS:

Among eighty included patients, 720 arteries were examined. An overall significant agreement of 96.5% was observed between TCD and MRA (Kappa = 0.377, P < 0.001). Compared to MRA, TCD had sensitivity of 42.1%, specificity of 99.6%, PPV of 72.7%, and NPV of 98.4% (ROC area: 0.708 [0.594–0.822]). TCD is specifically accurate in evaluating middle cerebral artery (MCA) (ROC area = 0.83).

CONCLUSIONS:

The high NPV of TCD in our study indicates the utility of TCD as a diagnostic test to exclude the presence of intracranial stenosis. This study supports TCD as a convenient, safe, and reproducible imaging modality applicable in the screening of intracranial stenosis, especially to evaluate MCA.

Thrombectomy in DAWN- and DEFUSE-3-Ineligible Patients: A Subgroup Analysis From the BEST Prospective Cohort Study

BACKGROUND

Because of the overwhelming benefit of thrombectomy for highly selected trial patients with large vessel occlusion (LVO), some trial-ineligible patients are being treated in practice.

OBJECTIVE

To determine the safety and efficacy of thrombectomy in DAWN/DEFUSE-3-ineligible patients.

METHODS

Using a multicenter prospective observational study of consecutive patients with anterior circulation LVO who underwent late thrombectomy, we compared symptomatic intracerebral hemorrhage (sICH) and good outcome (90-d mRS 0-2) among DAWN/DEFUSE-3-ineligible patients to trial-eligible patients and to untreated DAWN/DEFUSE-3 controls.

RESULTS

Ninety-eight patients had perfusion imaging and underwent thrombectomy >6 h; 46 (47%) were trial ineligible (41% M2 occlusions, 39% mild deficits, 28% ASPECTS <6). In multivariable regression, the odds of a good outcome (aOR 0.76, 95% CI 0.49-1.19) and sICH (aOR 3.33, 95% CI 0.42-26.12) were not different among trial-ineligible vs eligible patients. Patients with mild deficits were more likely to achieve a good outcome (aOR 3.62, 95% CI 1.48-8.86) and less sICH (0% vs 10%, P = .16), whereas patients with ASPECTS <6 had poorer outcomes (aOR 0.14, 95% CI 0.05-0.44) and more sICH (aOR 24, 95% CI 5.7-103). Compared to untreated DAWN/DEFUSE-3 controls, trial-ineligible patients had more sICH (13%BEST vs 3%DAWN [P = .02] vs 4%DEFUSE [P = .05]), but were more likely to achieve a good outcome at 90 d (36%BEST vs 13%DAWN [P < .01] vs 17%DEFUSE [P = .01]).

CONCLUSION

Thrombectomy is used in practice for some patients ineligible for the DAWN/DEFUSE-3 trials with potentially favorable outcomes. Additional trials are needed to confirm the safety and efficacy of thrombectomy in broader populations, such as large core infarction and M2 occlusions.

Multifocal transcranial stimulation in chronic ischemic stroke: A phase 1/2a randomized trial

BACKGROUND AND PURPOSE

Repetitive transcranial magnetic stimulation (rTMS) may promote recovery of motor function after stroke by inducing functional reorganization of cortical circuits. The objective of this study was to examine whether multifocal cortical stimulation using a new wearable transcranial rotating permanent magnet stimulator (TRPMS) can promote recovery of motor function after stroke by inducing functional reorganization of cortical circuits.

METHODS

Thirty³⁰ patients with chronic ischemic stroke and stable unilateral weakness were enrolled in a Phase 1/2a randomized double-blind sham-controlled clinical trial to evaluate safety and preliminary efficacy. Bilateral hemispheric stimulation was administered for 20 sessions 40 min each over 4 weeks. The primary efficacy endpoint was the change in functional MRI BOLD activation immediately after end of treatment. Secondary efficacy endpoints were clinical scales of motor function, including the Fugl-Meyer motor arm score, ARAT, grip strength, pinch strength, gait velocity, and NIHSS.

RESULTS

TRPMS treatment was well-tolerated with no device-related adverse effects. Active treatment produced a significantly greater increase in the number of active voxels on fMRI than sham treatment (median +48.5 vs -30, p = 0.038). The median active voxel number after active treatment was 8.8-fold greater than after sham (227.5 vs 26, p = 0.016). Although the statistical power was inadequate to establish clinical endpoint benefits, numerical improvements were demonstrated in 5 of 6 clinical scales of motor function. The treatment effects persisted over a 3-month duration of follow-up.

CONCLUSIONS

Multifocal bilateral TRPMS was safe and showed significant fMRI changes suggestive of functional reorganization of cortical circuits in patients with chronic ischemic stroke. A larger randomized clinical trial is warranted to verify recovery of motor function.

Noncontrast CT versus Perfusion-Based Core Estimation in Large Vessel Occlusion: The Blood Pressure after Endovascular Stroke Therapy Study

BACKGROUND AND PURPOSE

The 2018 AHA guidelines recommend perfusion imaging to select patients with acute large vessel occlusion (LVO) for thrombectomy in the extended window. However, the relationship between noncontrast CT and CT perfusion imaging has not been sufficiently characterized >6 hours after last known normal (LKN).

METHODS

From a multicenter prospective cohort of consecutive adults who underwent thrombectomy for anterior LVO 0-24 hours after LKN, we correlated baseline core volume (rCBF < 30%) and the Alberta Stroke Program Early CT Scale (ASPECTS) score. We compared perfusion findings between patients with an unfavorable ASPECTS (<6) against those with a favorable ASPECTS (≥6), and assessed findings over time.

RESULTS

Of 485 enrolled patients, 177 met inclusion criteria (median age: 69 years, interquartile range [IQR: 57-81], 49% female, median ASPECTS 8 [IQR: 6-9], median core 10 cc [IQR: 0-30]). ASPECTS and core volume moderately correlated (r = -.37). A 0 cc core was observed in 54 (31%) patients, 70% of whom had ASPECTS <10. Of the 28 patients with ASPECTS <6, 3 (11%) had a 0 cc core. After adjustment for age and stroke severity, there was a lower ASPECTS for every 1 hour delay from LKN (cOR: 0.95, 95% confidence of interval [CI]: 0.91-1.00, P = .04). There was no difference in core (P = .51) or penumbra volumes (P = .87) across patients over time.

CONCLUSIONS

In this multicenter prospective cohort of patients who underwent thrombectomy, one-third of patients had normal CTP core volumes despite nearly three quarters of patients showing ischemic changes on CT. This finding emphasizes the need to carefully assess both noncontrast and perfusion imaging when considering thrombectomy eligibility.

Blood Pressure after Endovascular Therapy for Ischemic Stroke (BEST): A Multicenter Prospective Cohort Study

Background and Purpose- To identify the specific post-endovascular stroke therapy (EVT) peak systolic blood pressure (SBP) threshold that best discriminates good from bad functional outcomes (a priori hypothesized to be 160 mm Hg), we conducted a prospective, multicenter, cohort study with a prespecified analysis plan. Methods- Consecutive adult patients treated with EVT for an anterior ischemic stroke were enrolled from November 2017 to July 2018 at 12 comprehensive stroke centers accross the United States. All SBP values within 24 hours post-EVT were recorded. Using Youden index, the threshold of peak SBP that best discriminated primary outcome of dichotomized 90-day modified Rankin Scale score (0-2 versus 3-6) was identified. Association of this SBP threshold with the outcomes was quantified using multiple logistic regression. Results- Among 485 enrolled patients (median age, 69 [interquartile range, 57-79] years; 51% females), a peak SBP of 158 mm Hg was associated with the largest difference in the dichotomous modified Rankin Scale score (absolute risk reduction of 19%). Having a peak SBP >158 mm Hg resulted in an increased likelihood of modified Rankin Scale score 3 to 6 (odds ratio, 2.24 [1.52-3.29], P<0.01; adjusted odds ratio, 1.29 [0.81-2.06], P=0.28, after adjustment for prespecified variables). Conclusions- A peak post-EVT SBP of 158 mm Hg was prospectively identified to best discriminate good from bad functional outcome. Those with a peak SBP >158 had an increased likelihood of having a bad outcome in unadjusted, but not in adjusted analysis. The observed effect size was similar to prior studies. This finding should undergo further testing in a future randomized trial of goal-targeted post-EVT antihypertensive treatment.

Cost-effectiveness of percutaneous closure of a patent foramen ovale compared with medical management in patients with a cryptogenic stroke: from the US payer perspective

Aims: To evaluate the cost-effectiveness of percutaneous patent foramen ovale (PFO) closure, from a US payer perspective. Lower rates of recurrent ischemic stroke have been documented following percutaneous PFO closure in properly selected patients. Stroke in patients aged <60 years is particularly interesting because this population is typically at peak economic productivity and vulnerable to prolonged disability. Materials and methods: A Markov model comprising six health states (Stable after index stroke, Transient ischemic attack, Post-Transient Ischemic Attack, Clinical ischemic stroke, Post-clinical ischemic stroke, and Death) was constructed to evaluate the cost-effectiveness of PFO closure in combination with medical management versus medical management alone. The base-case model employed a 5-year time-horizon, with transition probabilities, clinical inputs, costs, and utility values ascertained from published and national costing sources. Incremental cost-effectiveness ratio (ICER) was evaluated per US guidelines, utilizing a discount rate of 3.0%. Results: At 5 years, overall costs and quality-adjusted life-years (QALYs) obtained from PFO closure compared with medical management were $16,323 vs $7,670 and 4.18 vs 3.77, respectively. At 5 years, PFO closure achieved an ICER of $21,049, beneficially lower than the conventional threshold of $50,000. PFO closure reached cost-effectiveness at 2.3 years (ICER = $47,145). Applying discount rates of 0% and 6% had a negligible impact on base-case model findings. Furthermore, PFO closure was 95.4% likely to be cost-effective, with a willingness-to-pay (WTP) threshold of $50,000 and a 5-year time horizon. Limitations: From a cost perspective, our economic model employed a US patient sub-population, so cost data may not extrapolate to other non-US stroke populations. Conclusion: Percutaneous PFO closure plus medical management represents a cost-effective approach for lowering the risk of recurrent stroke compared with medical management alone.

Abstract 94: Blood Pressure After Endovascular Stroke Therapy (BEST): Final Results of a Prospective Multicenter Cohort Validation Study

Background: Limited data currently inform optimal post-endovascular therapy (EVT) blood pressure management. Systolic BP (SBP) >160 mmHg during the 24-hrs post-EVT correlated with worse outcomes in our retrospective multicenter study. To prospectively determine and potentially validate the specific post-EVT SBP threshold that discriminates functional outcomes, we designed a multicenter, prospective cohort study - “Blood Pressure after Endovascular Stroke Therapy (BEST)” - with a prespecified analysis plan.

Methods: Consecutive EVT-treated adult patients with ICA, M1, or M2 occlusions were enrolled at 12 comprehensive stroke centers, excluding those with disability, terminal diagnoses, LVAD, and in-hospital stroke. Baseline, treatment characteristics, and all SBP values during the 24 hrs post-EVT were captured. The primary outcome was 90d mRS (0-2 vs 3-6) adjusted for age, baseline NIHSS, glucose, ASPECTS, time to reperfusion, and history of hypertension. Secondary outcomes were intracerebral hemorrhage (ICH), symptomatic ICH, mRS distribution, and early neurologic recovery (ENR). A sample size of 340 was calculated to provide 80% power to detect a 1.36 odds ratio (i.e., 8% difference in mRS 3-6 rate) at α=0.05; inflated to 450 patients for up to 25% loss to follow up. The threshold of peak SBP that best discriminates mRS 0-2 vs. 3-6 will be identified with Youden’s index, and its association with outcomes will be quantified using logistic regression. Subgroup analysis by mTICI score and associations of other BP parameters with outcomes will be explored. Missing 90d outcomes will be imputed.

Results: We enrolled 457 patients from 11/2017 to 7/2018 with mean age 68y (±15), 52% females, median NIHSS 16 (IQR 11,20), and ASPECTS 8 (IQR 7,10). 221 (48%) patients received alteplase and 402 (88%) achieved mTICI 2b-3. Mean peak SBP was 165±24 mmHg in mTICI2b-3 group and 171±22 in mTICI 0-2a group, and 352 (77%) received an IV antihypertensive. 331 (73%) patients have outcomes available at 90d; rest are expected by 10/2018. Final results will be presented at ISC.

Conclusion: Expected results from BEST will inform clinical care and guide a developing randomized trial of targeted antihypertensive treatment in EVT-treated stroke patients.

Abstract WMP3: DEFUSE-3 Eligible but DAWN Ineligible Patients Treated Within 16-24 Hours: Results From BEST Prospective Cohort Study

Background: The 2018 ASA guidelines recommend endovascular stroke treatment (EVT) for patients who meet DEFUSE 3 (D3) trial criteria within 6-16 hrs and those who meet DAWN criteria within 6-24 hrs of last known well (LKW). Recommendation to use more restrictive DAWN and not D3 criteria between 16 and 24 hrs is not strictly followed in clinical practice. Using the prospective multi-institutional cohort study, “Blood Pressure after EVT (BEST),” we determined the frequency and outcomes of EVT-treated patients within the 16-24 hrs of LKW who met D3 but not DAWN criteria.

Methods: BEST enrolled consecutive EVT-treated adult patients with ICA, M1, or M2 occlusions at 12 comprehensive stroke centers from 11/2017 to 7/2018. D3-but not DAWN-eligible patients were defined as those with ICA/M1 occlusions, a mismatch volume 15cc, and any of the following: 1) NIHSS 6-9, 2) infarct core 51-70 cc, 3) age 80 yrs and infarct core 21-70 cc, or 4) NIHSS 11-19 , age <80 yrs and infarct core 31-70 cc. We compared mTICI score, symptomatic ICH, discharge disposition, and 90-day mRS in patients who met D3 but not DAWN criteria (16-24 hrs) to those who strictly met criteria for 1) D3 (6-16 hrs) and 2) DAWN (6-24 hrs).

Results: Of 457 patients, 159 (35%) underwent EVT within 6-24 hrs (mean age 66 yrs; 51% female; median NIHSS 14 [IQR: 9, 19]), and 26 (16%) were within 16-24 hrs. Of the 16-24 hr group, 8 (31%) met D3 but not DAWN criteria. Proportion of mTICI 2b-3, symptomatic ICH, and discharge disposition distribution were not different compared those who met full D3 or DAWN criteria. 90-day functional outcomes were better than those who met the full DAWN criteria (table).

Conclusion: One in three patients treated with EVT within 16-24 hrs of LKW at major academic comprehensive stroke centers did not meet current guideline recommendations (DAWN criteria). In this small sample size study, safety and outcome results are comparable to those who met guideline criteria. Dedicated studies are needed to confirm this finding.

Abstract WMP21: Underestimation of Ischemic Core on Perfusion CT in Patients With Acute Large Vessel Occlusion: Results From the BEST Prospective Cohort Study

Background: The 2018 AHA guidelines recommend patients with acute large vessel occlusion (LVO) be considered for thrombectomy in the 6 to 24-hour window based on perfusion imaging. Within 6 hours, CT perfusion (CTP) core estimates may underestimate volume of irreversible infarction visualized on the unenhanced CT; however this has not been well characterized in later time windows.

Methods: Using a multi-center prospective cohort of consecutive patients who underwent thrombectomy for LVO 0-24 hours after last known normal, we correlated baseline CTP core infarct volume (rCBF<30%) and unenhanced CT ASPECTS score, as recorded by local investigators. We compared CTP findings between patients with an unfavorable ASPECTS (<6) against those with a favorable ASPECTS (≥6), and assessed findings over time.

Results: Of 443 enrolled patients, 165 who underwent CTP were included (median age 69y [IQR 57-80], 83 [50%] female, with a median ASPECTS of 8 [IQR 6-9] and core of 9cc [IQR 0-28]). ASPECTS and core volume moderately correlated (r=-0.35, p<0.01). An absent core (0cc) was observed in 52/165 (32%) patients, among whom the median ASPECTS score was 8 (IQR 8-10). Of the 28 patients with unfavorable ASPECTS, 3 had a normal core volume (11%, 95%CI 2 - 28%). As time to recanalization progressed, the ASPECTS score worsened (common OR 1.05, 95%CI 1.01-1.09, p=0.02) whereas the core (p=0.66) and penumbra volumes (p=0.70) remained unchanged. After adjustment for age and baseline NIHSS, the decline in ASPECTS remained significant (cOR 1.05, 95%CI 1.01-1.10, p=0.01), while the core (p=0.69) and penumbra volumes (p=0.74) remained unchanged.

Conclusion: In this multi-center prospective cohort of patients who underwent thrombectomy, one-third of patients had normal core infarct volumes despite half of these patients showing irreversible infarction on the unenhanced CT (ASPECTS ≤8). As time progresses, the unenhanced CT demonstrates evolution of irreversible infarction, whereas the perfusion core appears static. This finding emphasizes the need to carefully assess both unenhanced CT and CTP when considering thrombectomy eligibility in the late time window, as was required by both DAWN and DEFUSE 3 selection criteria.

Abstract 109: Thrombectomy is Safe for Dawn- and Defuse-3-Ineligible Patients Who Present Within the Extended Window: A Subgroup Analysis From the BEST Prospective Cohort Study

Background: Recent data have demonstrated robust efficacy for endovascular thrombectomy in acute large vessel occlusion (LVO) up to 24h after symptom onset. Given the overwhelming benefit of this intervention in a highly selective, clinical trial population, it is plausible that a benefit may also be observed in some trial-ineligible patients.

Methods: Using the BEST multi-center prospective cohort of consecutive patients who underwent thrombectomy for LVO, we compared DAWN and DEFUSE 3 trial-ineligible patients treated within 6-24 hours after last known normal (LKN) to trial-eligible patients, and to untreated controls from those trials. The co-primary outcomes were an early therapeutic response (decrease in NIHSS ≥10, or NIHSS 0-1 by 24h) and good functional outcome (90-day mRS 0-2). Secondary outcomes included change in NIHSS at 24h, intracerebral hemorrhage within 72h, and discharge to home or acute rehab.

Results: Of 443 patients in the BEST cohort, 159 (36%) underwent endovascular therapy between 6-24 hours after LKN, of whom 71 (45%) were trial-ineligible. The most common trial exclusion criteria were M2 (53%) and multivessel occlusions (30%). Compared to trial-eligible patients, trial-ineligible patients were younger (median 63 vs. 72y, p=0.02) but had similar baseline NIHSS (median 14 vs. 15, p=0.28), ASPECTS scores (median 8 v. 8, p=0.69), times to recanalization (median 627 vs. 682 min, p=0.08), and rates of successful recanalization (TICI 2b/3, 83% v. 86%, p=0.57). Compared to DAWN untreated controls, BEST trial-ineligible patients were more likely to have an early therapeutic response (OR 2.02, 95%CI 1.00-4.06, p=0.049) and good functional outcome (OR 3.02, 95%CI 1.33-6.86, p=0.001). Compared to trial-eligible patients in BEST, trial-ineligible patients had similar improvements in 24h NIHSS (-2 vs. -4, p=0.33), rates of intracerebral hemorrhage (28% vs. 24%, p=0.54), and rates of discharge to home or rehab (77% vs. 73%, p=0.49).

Conclusion: This multicenter prospective cohort demonstrates that thrombectomy for acute LVO within 24 hours in DAWN and DEFUSE 3 trial-ineligible patients is safe and may be effective. Treating these patients may be reasonable but our findings should be confirmed by additional randomized data trials.

Human tissue kallikrein in the treatment of acute ischemic stroke

Acute ischemic stroke (AIS) remains a major cause of death and disability throughout the world. The most severe form of stroke results from large vessel occlusion of the major branches of the Circle of Willis. The treatment strategies currently available in western countries for large vessel occlusion involve rapid restoration of blood flow through removal of the offending blood clot using mechanical or pharmacological means (e.g. tissue plasma activator; tPA). This review assesses prospects for a novel pharmacological approach to enhance the availability of the natural enzyme tissue kallikrein (KLK1), an important regulator of local blood flow. KLK1 is responsible for the generation of kinins (bradykinin and kallidin), which promote local vasodilation and long-term vascularization. Moreover, KLK1 has been used clinically as a direct treatment for multiple diseases associated with impaired local blood flow including AIS. A form of human KLK1 isolated from human urine is approved in the People's Republic of China for subacute treatment of AIS. Here we review the rationale for using KLK1 as an additional pharmacological treatment for AIS by providing the biochemical mechanism as well as the human clinical data that support this approach.

Patent Foramen Ovale in Cryptogenic Stroke and Migraine with Aura: Does Size Matter?

Introduction: There is an association between cryptogenic strokes and patent foramen ovale (PFO), as well as between migraines with aura and PFO. The purpose of the current study was to compare shunt characteristics in the stroke and migraine populations.

Methods: We retrospectively evaluated the degree of the shunt in 68 consecutive patients with cryptogenic stroke (n=33) or migraines with aura (n=35) evaluated in a single transcranial Doppler laboratory. All patients underwent an intravenous injection of agitated saline, followed by the insonation of the middle cerebral artery to determine the degree of the right-to-left shunt. We graded the shunt size according to the number of emboli: Grade I, none; Grade II, 1-10; Grade III, 11-100; and Grade IV, >100. Grades I and II were considered low-grade shunts, and Grades III and IV were considered high-grade.

Results: In the 14-month study period, we found 31 high-grade shunts and 37 low-grade shunts. Among migraines with aura patients, 27 (77%) had high-grade shunts, whereas only 4 patients (12%) with cryptogenic stroke had high-grade shunts. These percentages were significantly different between groups (Fisher’s exact test, p<0.0001).

Conclusions: In a standardized laboratory using uniform methods, we found a significant difference in shunt size associated with PFO between cryptogenic stroke and migraine with aura patients. We hypothesize that in migraines with aura, venous admixture with arterial blood is the main mechanism by which PFO contributes to the condition. In contrast, cryptogenic strokes associated with PFO are more likely to arise from an atrial septal clot within the PFO space.

Changes in Transcranial Sonographic Measurement of the Optic Nerve Sheath Diameter in Non-concussed Collegiate Soccer Players Across a Single Season

Introduction

Bedside ultrasound measurement of the optic nerve sheath diameter (ONSD) is emerging as a non-invasive technique to evaluate and predict raised intracranial pressure (ICP) in both children and adults. The prognostic value of increased ONSD on brain computed tomography (CT) scan has previously been correlated with increased intensive care unit (ICU) mortality in patients with severe traumatic brain injury (TBI). Previous studies have also evaluated the association between high-contact sports, such as soccer, and TBI; however, the related changes in ONSD are still unknown. The aim of this study was to evaluate for the natural evolution of changes in ONSD in athletes who participate in high-contact sports.

Methods

In this prospective observational study, volunteers from a collegiate women’s soccer team underwent the measurement of ONSD with transcranial Doppler (TCD). ONSDs were measured during the initial visit during the pre-season period and again at the three-month follow-up. A single experienced neuro-sonographer performed all measurements to eliminate any operator bias.

Results

Twenty-four female college soccer players between the ages of 18 and 23 were included in this analysis. Mean ONSD during the initial pre-season clinic visit and the three-month follow-up were 4.14±0.6 mm and 5.02±0.72 mm, respectively (P < 0.0001). A two-tailed t-test analysis was performed, which resulted in a t-value of 4.76 and P < 0.00001. The average ONSD measured during the post-season follow-up showed a 21.3% increase compared to the baseline.

Conclusion

The evaluation of high-contact sports athletes is limited due to the lack of objective radiologic and diagnostic tools. Moreover, in an athlete suffering a concussion, return-to-play decisions are heavily dependent on the symptoms reported by the athletes. In our analysis of collegiate women’s soccer players, active participation in soccer competitions and practice may be associated with an increase in ONSD, independent of concussions. Further studies are underway to evaluate the clinical significance of these findings as well as possible correlations between concussions and changes in ONSD.

Allogeneic Umbilical Cord Blood Infusion for Adults with Ischemic Stroke: Clinical Outcomes from a Phase I Safety Study

Stroke is a major cause of death and long‐term disability, affecting one in six people worldwide. The only currently available approved pharmacological treatment for ischemic stroke is tissue plasminogen activator; however, relatively few patients are eligible for this therapy. We hypothesized that intravenous (IV) infusion of banked unrelated allogeneic umbilical cord blood (UCB) would improve functional outcomes in patients with ischemic stroke. To investigate this, we conducted a phase I open‐label trial to assess the safety and feasibility of a single IV infusion of non‐human leukocyte antigen (HLA) matched, ABO matched, unrelated allogeneic UCB into adult stroke patients. Ten participants with acute middle cerebral artery ischemic stroke were enrolled. UCB units were matched for blood group antigens and race but not HLA, and infused 3–9 days post‐stroke. The adverse event (AE) profile over a 12 month postinfusion period indicated that the treatment was well‐tolerated in these stroke patients, with no serious AEs directly related to the study product. Study participants were also assessed using neurological and functional evaluations, including the modified Rankin Score (mRS) and National Institute of Health Stroke Scale (NIHSS). At 3 months post‐treatment, all participants had improved by at least one grade in mRS (mean 2.8 ± 0.9) and by at least 4 points in NIHSS (mean 5.9 ± 1.4), relative to baseline. Together, these data suggest that a single i.v. dose of allogeneic non‐HLA matched human UCB cells is safe in adults with ischemic stroke, and support the conduct of a randomized, placebo‐controlled phase 2 study. stemcellstranslationalmedicine2018;7:521–529

Systolic Blood Pressure Within 24 Hours After Thrombectomy for Acute Ischemic Stroke Correlates With Outcome

Background

Current guidelines suggest treating blood pressure above 180/105 mm Hg during the first 24 hours in patients with acute ischemic stroke undergoing any form of recanalization therapy. Currently, no studies exist to guide blood pressure management in patients with stroke treated specifically with mechanical thrombectomy. We aimed to determine the association between blood pressure parameters within the first 24 hours after mechanical thrombectomy and patient outcomes.

Methods and Results

We retrospectively studied a consecutive sample of adult patients who underwent mechanical thrombectomy for acute ischemic stroke of the anterior cerebral circulation at 3 institutions from March 2015 to October 2016. We collected the values of maximum, minimum, and average values of systolic blood pressure, diastolic blood pressure, and mean arterial pressures in the first 24 hours after mechanical thrombectomy. Primary and secondary outcomes were patients’ functional status at 90 days measured on the modified Rankin scale and the incidence and severity of intracranial hemorrhages within 48 hours. Associations were explored using an ordered multivariable logistic regression analyses. A total of 228 patients were included (mean age 65.8±14.3; 104 males, 45.6%). Maximum systolic blood pressure independently correlated with a worse 90‐day modified Rankin scale and hemorrhagic complications within 48 hours (adjusted odds ratio=1.02 [1.01–1.03], P=0.004; 1.02 [1.01–1.04], P=0.002; respectively) in multivariable analyses, after adjusting for several possible confounders.

Conclusions

Higher peak values of systolic blood pressure independently correlated with worse 90‐day modified Rankin scale and a higher rate of hemorrhagic complications. Further prospective studies are warranted to identify whether systolic blood pressure is a therapeutic target to improve outcomes.

Transient Ischemic Attack in the Setting of Carotid Atheromatous Disease with a Persistent Primitive Hypoglossal Artery Successfully Treated with Stenting: A Case Report

Fetal brain perfusion is supplied by the primitive dorsal aorta anteriorly, longitudinal neural arteries posteriorly, and anastomotic transverse segmentals. Most notable of these connections are the primitive trigeminal, otic, hypoglossal, and proatlantal arteries. With cranial-cervical circulatory maturation and development of the posterior communicating segments and vertebro-basilar system, these primitive segmental anastomoses normally regress. Anomalous neurovascular development can result in persistence of these anastomoses. Due to its territory of perfusion, the persistent primitive hypoglossal artery (PPHA) is associated with vertebral artery and posterior communicating artery hypoplasia or aplasia. As a consequence, primary blood supply to the hindbrain comes chiefly from this single artery. Although usually clinically silent, PPHA is susceptible to common cerebrovascular disorders including athero-ischemic disease and saccular aneurysmal dilation to name a few. We present a case of transient ischemic attack in a patient with a PPHA and proximal atherosclerotic disease treated by endovascular stenting. 

Abstract NS5: Early Infection Worsens ICH

Background: Intracerebral hemorrhage (ICH) is a dynamic disease in which coagulopathy, early re-bleeds, and tissue ischemia account for potential decline. Infection is known to contribute to coagulopathy and ischemia and may be a significant source of early decline and worse initial clinical presentation.

Hypothesis: Infection within 72 hours is an independent marker of early decline in hemorrhagic stroke.

Methods: To validate our hypothesis, we retrospectively analyzed infection and ICH presentation in 53 ICH patients at Houston Methodist Hospital from 2011-2013. We used the Glasgow Coma Score (GCS) on admission and the ICH Score as the primary outcome data on the severity of the initial clinical presentation of ICH patients. We considered the following diagnostic measures to determine infection within 72 hours: fever, leukocytosis, positive blood culture, positive urinalysis, positive chest X-ray, and use of non-prophylactic antibiotics. If any one of the diagnostic measures was positive then we counted the patient as having an infection within 72 hours. Additionally, we developed an Infection on Admission Score as the sum of each measure to establish a scale for the certainty and possible severity of infection with higher scores suggesting greater certainty and severity.

Results: Any marker of infection within 72 hours was independently associated with lower GCS on admission ( P =0.0259). Using the Infection on Admission Score , we found that a higher score was also independently associated with higher (or more severe) ICH score ( P = .0025) and with lower GCS ( P = .0070).

Conclusions: Any sign of infection within 72 hours correlates with a worse initial clinical presentation of hemorrhagic stroke. Furthermore, these data suggest a physiological influence, as the severity of ICH rose in relationship to the severity of infection. We suggest further studies into this relationship to determine if infection itself causes decline or is simply a marker of overall decline.

Abstract W P151: Aging is Associated With Progressive Insufficiency of Circle of Willis Collaterals in Humans

Introduction: Increasing age is the single largest non-modifiable risk factor for ischemic stroke. Recent studies have shown that increasing age is associated with inadequacy of leptomeningeal collaterals, and aging has been shown to cause a progressive decline in the number and diameter of collateral vessels in experimental mice, resulting in an increased collateral resistance and an enhanced stroke severity.

Hypothesis: Aging leads to progressive loss of Circle of Willis collateral vessels in humans.

Method: We studied a retrospective, consecutive series of 167 women and 112 men undergoing cerebral angiography for any reason. A blinded investigator scored the Circle of Willis collaterals for each angiogram using a scoring system of 0 - 2 for each collateral (0 = absent, 1 = hypo-plastic, 2 = robust) for a total score of 0 - 14. Collaterals scored included the bilateral A1 segments of the anterior cerebral arteries, bilateral P1 segments of the posterior cerebral arteries, bilateral posterior communicating arteries, and the anterior communicating artery. We compared the number of collaterals based on age, gender, and race as well as history of prior infarct, aneurysm, smoking, hypertension, diabetes, and obesity.

Results: Females had significantly more collaterals than men (p = 0.04) . The average collateral score for males and females was 10.77 and 11.14, respectively. Patients younger than 60 years of age had a significantly higher number of collaterals (average collateral score, 11.54) compared with patients older than 60 (average collateral score, 10.47; p = 1.59 x 10 -9 ). Females exhibited a greater loss of collaterals with advancing age (p = 3.53 x 10 -5 ) than men (p = 0.00016). Data was subjected to the Dunn-Bonferroni corrected t-test for preplanned comparisons or the Student t-test.

Conclusion: Based on our study, patients younger than 60 years are significantly more likely to have an angiographically-complete Circle of Willis. The underlying mechanism for this effect in humans is uncertain and the subject of a future study.

Abstract 3703: Utility of Cardiac MRI in Evaluation of Stroke Subtypes

Introduction : Cardiac magnetic resonance imaging (CMR) is a novel imaging modality that may aid in identifying potential cardiac etiology of ischemic stroke. We assessed the prevalence of cardiac abnormalities by the CMR in a population of patients with acute stroke.

Patients and Methods : We performed CMR on 89 patients who were admitted to our stroke service between August 2009 and June 2011. None of these patients had MRI contraindication. Of those, 13 patients were excluded due to negative diffusion weighted MRI, one was excluded for having intracranial bleeding, and one for having vertebral artery dissection as the source of stroke. The remaining 74 patients with DWI positive or CT positive acute stroke were analyzed for abnormalities on cardiac MRI. CMR along with other routine stroke work up including MRI of the brain and MRA of head and neck were done for these patients within the first 48 hours of their admission. We consider cardioembolic etiology as definite, probable, or possible based on the presence of an abnormality on the CMR. We consider atherothrombotic etiology as definite, probable, or possible if there was a 50% or greater arterial stenosis identified in the territory of the infarct.

Results : In our 74 patients, we found definite cardioembolic source in 21 patients (28.3%), definite atherothrombotic source in 14 patients (18.9%) and no definite etiology in 12 patients (16.2%).In the other patients (36.4%), there was at least one abnormality in CMR or MRA head /neck which could be considered as the probable or possible etiology of acute stroke. In the patients with definite cardioembolic source (21 patients), enlargement of left atrium were found in 9 (43%), systolic dysfunction in 6 (29%), mural thrombus in 5 (24%), mural scar in 4 (19%), myocardial infarction in 2 (9%) and cardiac mass in 1 (5%).

Conclusion: CMR is an effective non-invasive modality in diagnosing cardioembolic etiologies in patients with stroke. Further studies to compare the effectiveness of CMR with other modalities such as transesophageal echocardiography are recommended.