Abstract WP7: Mstu Validation Of A Pre-reperfusion Map For Better Thrombectomy Outcomes

Background: We sought to determine and validate a pre-reperfusion blood pressure threshold for MCA occlusions patients with better thrombectomy outcomes.

Methods: We reviewed patients from 2013 to 2015 treated with thrombectomy for a MCA M1 occlusion at our center. Blood pressure measurements from available records at the time of EMS activation to the time of reperfusion were used to calculate an averaged pre-reperfusion mean arterial pressure (MAP). All patients in our analysis had successful reperfusion. Our endpoint was a mRS ≤2 at 90 days. The averaged MAP was grouped as follows: ≥85mmHg, ≥90mmHg, ≥95mmHg, ≥100mmHg, ≥110 mmHg and ≥115mmHg. We considered hourly epochs from symptom onset to reperfusion, pre-treatment ASPECTS, thrombolytics, and collateral status. Significant parameters from a univariate analysis were included into a multivariate logistic regression to determine independent predictors of outcome. The multivariate findings were then validated with a prospective set of similar patients evaluated with our mobile stroke treatment unit.

Results: We reviewed 52 patients. Mean age was 70; NIHSS was 16±6; 40% (21) received t-PA; median ASPECTS score was 10; TICI 3 score was achieved in 63% (33), and 67% (35) had a good outcome. The number of patients having a mean arterial blood pressure threshold were as follows: ≥85mmHg (96%), ≥90mmHg (83%), ≥95mmHg (73%), ≥100mmHg (58%), ≥110mmHg (31%) and ≥115mmHg (15%). Reperfusion occurred as follows: ≤3hrs (4%), ≤4hrs (21%), ≤5hrs (39%), ≤6hrs (52%), ≤7hrs (67%), ≤8hrs (79%), ≤9hrs (87%), and ≤12hrs (90%). Our multivariate logistic regression model identified an average pre-reperfusion MAP ≥95mmHg as the sole factor statistically associated with a better outcome post successful thrombectomy [OR 15.1, CI 1.3-170.1,p=0.02]. Good clinical outcome in those patients with an averaged MAP ≥95mmHg was 76% and 43% in those below the threshold [OR 5.2, p=0.02]. Our validation cohort consisted of 32 patients, and a pre-reperfusion averaged MAP ≥ 95 mmHg had a sensitivity of of 93% for a good outcome.

Conclusion: Our analysis suggests with validation that a pre-reperfusion averaged MAP ≥ 95mmHg results in better outcomes with successful thrombectomy and may be used as a therapeutic target in the pre-hospital setting.

Abstract P219: Effect Of Hypertension On Clinical Recovery After Stroke Thrombectomy

Title: Effect of hypertension on clinical recovery after stroke thrombectomy

Objective: Our goal was to identify what vascular risk factors for stroke affect outcomes after mechanical thrombectomy.

Methods: We retrospectively reviewed stroke thrombectomy patients at our comprehensive stroke center from June 2013 to August 2016. Patients were determined to have atrial fibrillation, hypertension, diabetes, or hyperlipidemia based on historical information pre-treatment or based on hospital records during their index hospitalization. All patients in our series achieved recanalization after thrombectomy defined as a Thrombolysis in cerebral infarction (TICI) score of 2b or higher. Our endpoint was mild to moderate disability at 90 days defined by the modified Rankin Scale (mRS) score of 2 or less. We performed a univariate analysis on the above covariates affecting clinical outcome and studies all variables with a p-value of < 0.2 in a multivariate analysis to determine which independent variables affected outcome. Multi-variate analyses were performed separately for males and females.

Results: We reviewed 288 stroke patients that underwent thrombectomy. The mean age was 69±15; NIHSS was 17±6; 36% (104 of 288) received t-PA and 42% (121 of 288) had a modified Rankin Score of < 2. 42.7% (123 of 288) were females. From the entire group, 47.5% (137 of 288) had atrial fibrillation, 29% (83 of 288) had diabetes mellitus 68% (197 of 288) had hypertension, 38.5% (111 of 288) had hyperlipidemia and 16% (47 of 288) had a history of tobacco smoking. After considering positive univariates from above, our multivariate logistic regression model identified that not having hypertension [ OR 2.32, CI 1.01-5.41, p=0.05 ] predicted better outcome post thrombectomy procedure for males after a successful recanalization.

Conclusion: Our analysis suggests that, for males, the odds of a positive outcome after a successful thrombectomy procedure is positively influenced when the patient is not hypertensive. No traditional risk factor appeared to influence the outcome in females. Further prospective study is required to validate these findings.

Republished: A lumbar arteriovenous fistula presenting with intraventricular hemorrhage and hydrocephalus

Pediatric spinal vascular malformations are rare entities that typically present with symptoms from their effect on surrounding structures. Here we report a unique case of lumbar spinal dural/perimedullary arteriovenous fistula (AVF) that presented with intraventricular hemorrhage and hydrocephalus. The previously healthy child presented with lethargy and headache, and initial imaging revealed only ventriculomegaly with trace intraventricular blood. His mental status improved with CSF diversion via an external ventricular drain. Further workup revealed a spinal AVF that was treated via endovascular embolization. His course was complicated by vasospasm requiring endovascular treatment and he eventually required ventriculoperitoneal shunt placement. He made a full recovery and has returned to his normal activities. This is a unique case of spinal AVF presentation and highlights the importance of considering imaging of the entire neuroaxis during workup for hydrocephalus.

A lumbar arteriovenous fistula presenting with intraventricular hemorrhage and hydrocephalus

Pediatric spinal vascular malformations are rare entities that typically present with symptoms from their effect on surrounding structures. Here we report a unique case of lumbar spinal dural/perimedullary arteriovenous fistula (AVF) that presented with intraventricular hemorrhage and hydrocephalus. The previously healthy child presented with lethargy and headache, and initial imaging revealed only ventriculomegaly with trace intraventricular blood. His mental status improved with CSF diversion via an external ventricular drain. Further workup revealed a spinal AVF that was treated via endovascular embolization. His course was complicated by vasospasm requiring endovascular treatment and he eventually required ventriculoperitoneal shunt placement. He made a full recovery and has returned to his normal activities. This is a unique case of spinal AVF presentation and highlights the importance of considering imaging of the entire neuroaxis during workup for hydrocephalus.

Abstract TP215: Machine Learning Analysis of Gene Expression Data and Predictive Stroke Outcomes in Acute Ischemic Stroke

Background and Purpose: The ability to predict ischemic stroke outcomes in the first day of admission could be vital for patient counseling, rehabilitation, and care planning. The Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC; clinicaltrials.gov NCT03153683) collects blood samples distal and proximal to the intracranial thrombus during mechanical thrombectomy. These samples are a novel resource in evaluating acute gene expression changes at the time of ischemic stroke. The purpose of this study was to identify inflammatory genes and patient demographics that are predictive of stroke outcomes (infarct and/or edema volume) in acute ischemic stroke patients.

Methods: The BACTRAC study is a non-probability, convenience sampling of subjects (≥ 18 year olds) treated with mechanical thrombectomy for emergent large vessel occlusion. We evaluated relative concentrations of mRNA for gene expression in 84 inflammatory molecules in static blood distal and proximal to the intracranial thrombus from adults who underwent thrombectomy. We employed a machine learning method, Random Forest, utilizing the first set of enrolled subjects, to predict which inflammatory genes and patient demographics were important features for infarct and edema volumes.

Results: We analyzed the first 28 subjects (age = 66 ± 15.48, 11 males) in the BACTRAC registry. Results from machine learning analyses demonstrate that the genes CCR4, IFNA2, IL9, CXCL3, Age, DM, IL7, CCL4, BMI, IL5, CCR3, TNF, and IL27 predict infarct volume. The genes IFNA2, IL5, CCL11, IL17C, CCR4, IL9, IL7, CCR3, IL27, DM, and CSF2 predict edema volume. There is an intersection of genes CCR4, IFNA2, IL9, IL7, IL5, CCR3 to both infarct and edema volumes. Overall, these genes depicts a microenvironment for chemoattraction and proliferation of autoimmune cells, particularly Th2 cells and neutrophils.

Conclusions: Machine learning algorithms can be employed to develop predictive biomarker signatures for stroke outcomes in ischemic stroke patients, particularly in regard to identifying acute gene expression changes that occur during stroke.

Expression of Cytokines and Chemokines as Predictors of Stroke Outcomes in Acute Ischemic Stroke

Introduction: Ischemic stroke remains one of the most debilitating diseases and is the fifth leading cause of death in the US. The ability to predict stroke outcomes within the acute period of stroke would be essential for care planning and rehabilitation. The Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC; clinicaltrials.gov NCT03153683) study collects arterial blood immediately distal and proximal to the intracranial thrombus at the time of mechanical thrombectomy. These blood samples are an innovative resource in evaluating acute gene expression changes at the time of ischemic stroke. The purpose of this study was to identify inflammatory genes and important immune factors during mechanical thrombectomy for emergent large vessel occlusion (ELVO) and which patient demographics were predictors for stroke outcomes (infarct and/or edema volume) in acute ischemic stroke patients.

Methods: The BACTRAC study is a non-probability sampling of male and female subjects (≥18 year old) treated with mechanical thrombectomy for ELVO. We evaluated 28 subjects (66 ± 15.48 years) relative concentrations of mRNA for gene expression in 84 inflammatory molecules in arterial blood distal and proximal to the intracranial thrombus who underwent thrombectomy. We used the machine learning method, Random Forest to predict which inflammatory genes and patient demographics were important features for infarct and edema volumes. To validate the overlapping genes with outcomes, we perform ordinary least squares regression analysis.

Results: Machine learning analyses demonstrated that the genes and subject factors CCR4, IFNA2, IL-9, CXCL3, Age, T2DM, IL-7, CCL4, BMI, IL-5, CCR3, TNFα, and IL-27 predicted infarct volume. The genes and subject factor IFNA2, IL-5, CCL11, IL-17C, CCR4, IL-9, IL-7, CCR3, IL-27, T2DM, and CSF2 predicted edema volume. The overlap of genes CCR4, IFNA2, IL-9, IL-7, IL-5, CCR3, and IL-27 with T2DM predicted both infarct and edema volumes. These genes relate to a microenvironment for chemoattraction and proliferation of autoimmune cells, particularly Th2 cells and neutrophils.

Conclusions: Machine learning algorithms can be employed to develop prognostic predictive biomarkers for stroke outcomes in ischemic stroke patients, particularly in regard to identifying acute gene expression changes that occur during stroke.

Immune System Activation in Perioperative Thrombectomy Patients: Preliminary Retrospective Study

BACKGROUND

Ischemic stroke is a devastating condition resulting in significant morbidity. Mechanical thrombectomy is now standard for large vessel occlusive stroke. Neuroinflammation is known to play important roles in ischemic stroke. Our aims were to examine our thrombectomy procedures and preliminarily examine systemic immune response in relation to thrombectomy changes.

METHODS

A retrospective review was conducted on mechanical thrombectomy cases from July 2011 through December 2015. Primary outcomes were time to recanalization, final Thrombolysis in Cerebral Infarction score, procedural complications, National Institutes of Health Stroke Scale improvement, and changes in white blood cell (WBC) count.

RESULTS

One-hundred and twenty-nine procedures were performed. We found a significant difference between WBC count on admission and WBC count post thrombectomy day 1 for patients with >90 minutes to recanalization (P = 0.006107). There was a positive association between WBC change and absolute National Institutes of Health Stroke Scale change among females (P = 0.0273) but not among males.

CONCLUSIONS

Overall, we found that systemic immune response has close relationships with speed of recanalization and preliminarily may shift differently on the basis of sex.

Predictive value of platelet reactivity unit (PRU) value for thrombotic and hemorrhagic events during flow diversion procedures: a meta-analysis

BACKGROUND AND PURPOSE

Platelet function testing prior to flow diversion procedures, although initially heavily debated, has seen a substantial increase in its adoption to assess the risk of operative and perioperative thrombotic and hemorrhagic events. This meta-analysis was conducted to assess platelet function testing, particularly the VerifyNow Platelet Reactivity Unit (PRU) assay, for a relationship between the reported assay PRU value and thrombotic and hemorrhagic events.

MATERIALS AND METHODS

The currently available literature (2013-2018) was surveyed with PubMed and Google Scholar searches. Included studies were those for which there were at least 30 cases during the study period, for which VerifyNow platelet reactivity unit values were obtained prior to the procedures and for which intraoperative and perioperative adverse events were noted. PRU value cut-offs ranging from >200 to >240 comprised the hyporesponse group while values ranging from <60 to <70 comprised the hyper-response group. The data were subject to statistical analysis to assess the relationship between PRU values and thrombotic and hemorrhagic events. The collected data were subsequently statistically analyzed to assess for publication bias.

RESULTS

The searches yielded 27 studies, of which 12 met the inclusion criteria for the meta-analysis. The meta-analysis included data from 1464 reported Pipeline cases. The study included 273 men and 1177 women with a mean age across the analyzed procedures of 58 years (range 25-85). After loading with antiplatelet medications, preprocedural platelet hyper-responsiveness was associated with a greater incidence of hemorrhagic events with an increased absolute risk of 12%, but showed no relationship with thrombotic events. Preprocedural platelet hyporesponsiveness was associated with a greater incidence of thrombotic events with an absolute risk of 15%, but showed no relationship with hemorrhagic events.

CONCLUSIONS

VerifyNow PRU values that correspond to platelet hyporesponse or hyper-response to dual antiplatelet therapy are associated with a higher risk of thrombotic and hemorrhagic events, respectively. Thus, the PRU value may offer some predictive value for these events.

Abstract WP540: Acid Base and Electrolyte Alterations in Acute Large Vessel Occlusion Stroke

Background and Purpose: In the setting of mechanical thrombectomy for emergent large vessel occlusion (ELVO), we have developed a protocol to collect and evaluate blood immediately distal and proximal from the removed intracranial thrombus. These samples provide a unique resource in evaluating acute changes in acid/base and electrolyte concentrations at the time of ischemic stroke. The purpose of this study is to compare acid/base and electrolyte differences obtained proximal and distal to the occluded intracranial thrombus in acute ischemic stroke patients.

Methods: We developed the Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC) protocol: an IRB-approved tissue banking strategy for ELVO (clinicaltrials.gov NCT03153683). We compared arterial blood gases (ABG) of blood distal versus proximal to the thrombus during thrombectomy. Comparisons were evaluated by Paired Samples T-Tests (p < 0.05).

Results: We analyzed the first 46 subjects (age = 67 ± 14.23, 20 males) in the BACTRAC registry. Preliminary results demonstrate that, while pH is nonsignificant (p = 0.513), distal blood in relation to proximal blood showed significantly lower oxygen (p < 0.001), carbon dioxide (p < 0.001), bicarbonate (p < 0.001), ionized calcium (p < 0.001), and potassium (p < 0.001). Sodium concentration was significantly higher (p < 0.001) in distal blood. These results suggest alterations occurring intravascularly during ischemia.

Conclusions: These preliminary findings provide a novel insight into the pathology of large vessel stroke in humans, particularly in regard to identifying acute changes in acid/base balance and electrolyte concentrations that occur during stroke.

Abstract WMP45: Gene Expression Levels in Acute Large Vessel Occlusion Stroke in Humans

Background and Purpose: The Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC) tissue bank collects blood proximal and distal to the intracranial thrombus during the process of mechanical thrombectomy in human stroke patients. These samples provide a unique resource in evaluating acute gene expression changes at the time of ischemic stroke. The purpose of this study was to evaluate gene expression changes occurring within the thrombus and across the occlusion in the intravascular space in acute ischemic stroke patients.

Methods: We developed the BACTRAC protocol: an IRB-approved tissue banking approach for ELVO (clinicaltrials.gov NCT03153683). We evaluated relative concentrations of gene expression in 84 inflammatory molecules in thrombi removed from adults who received thrombectomy for ischemic stroke, in static blood distal to thrombus, and in peripheral circulation.

Results: We analyzed the first 46 subjects (age = 67 ± 14.23, 20 males) in the BACTRAC registry. Results from qPCR gene expression analyses demonstrate that 21 genes (CCL1, CCL11, CCL13, CCL17, CCL26, CCL8, CSF3, CX3CL1, CXCL1, CXCL9, IFNA2, IL13, IL17C, IL17F, IL1A, IL27, IL3, IL33, LTA, TNFSF11, and TNFSF13) had at least 25 mean fold change in the distal blood compared to the peripheral blood. Fourteen genes (AIMP1, CCL11, CCL13, CCL15, CCL16, CCL23, CCR2, CCR4, CCR8, CD40LG, CXCL10, IL10RA, IL15, and TNFSF13B) had at least 10 mean fold change in the thrombus compared to the peripheral blood. Overall, these genes are associated with chemo-attraction and cell proliferation of monocytes, neutrophils, and T cells.

Conclusions: These findings provide a novel insight into the initial pathology of large vessel stroke in humans, particularly in regard to identifying acute gene expression changes that occur during stroke.

The Blood And Clot Thrombectomy Registry And Collaboration (BACTRAC) protocol: novel method for evaluating human stroke

BACKGROUND

Ischemic stroke research faces difficulties in translating pathology between animal models and human patients to develop treatments. Mechanical thrombectomy, for the first time, offers a momentary window into the changes occurring in ischemia. We developed a tissue banking protocol to capture intracranial thrombi and the blood immediately proximal and distal to it.

OBJECTIVE

To develop and share a reproducible protocol to bank these specimens for future analysis.

METHODS

We established a protocol approved by the institutional review board for tissue processing during thrombectomy (www.clinicaltrials.gov NCT03153683). The protocol was a joint clinical/basic science effort among multiple laboratories and the NeuroInterventional Radiology service line. We constructed a workspace in the angiography suite, and developed a step-by-step process for specimen retrieval and processing.

RESULTS

Our protocol successfully yielded samples for analysis in all but one case. In our preliminary dataset, the process produced adequate amounts of tissue from distal blood, proximal blood, and thrombi for gene expression and proteomics analyses. We describe the tissue banking protocol, and highlight training protocols and mechanics of on-call research staffing. In addition, preliminary integrity analyses demonstrated high-quality yields for RNA and protein.

CONCLUSIONS

We have developed a novel tissue banking protocol using mechanical thrombectomy to capture thrombus along with arterial blood proximal and distal to it. The protocol provides high-quality specimens, facilitating analysis of the initial molecular response to ischemic stroke in the human condition for the first time. This approach will permit reverse translation to animal models for treatment development.

Abstract TMP107: Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC) Protocol: Novel Method for Evaluating Human Stroke

Background: Research in ischemic stroke struggles from failures to translate stroke conditions between animal models and human patients. With mechanical thrombectomy, we have for the first time developed a protocol to facilitate tissue banking of intracranial thrombi as well as the blood immediately proximal and distal to it. These tissues provide a unique resource to correlate changes in the human condition to animal models. Our aim was to develop a reproducible protocol to bank these specimens for future gene expression and proteomic analysis.

Methods: We developed an IRB-approved protocol for tissue processing during thrombectomy (www.clinicaltrials.gov NCT03153683). The protocol was a joint clinical/basic science effort among multiple laboratories and the Neurointerventional Radiology Service Line. We placed laboratory supplies in the angio suite, and developed a step-by-step protocol for specimen retrieval and processing.

Results: Our protocol successfully yielded samples for analysis in all but one case. In our preliminary dataset, the protocol yielded adequate amounts of tissue for distal blood, proximal blood, and thrombus. We present the tissue banking protocol for dissemination, and highlight the training protocol and mechanics of on-call research staffing for 24/7 tissue processing. In addition, preliminary integrity analyses demonstrated high quality yields for RNA and protein.

Conclusion: We have developed a novel tissue banking protocol to capture thrombus, and both proximal and distal blood to the intracranial thrombus in human stroke patients. The specimens are captured during the thrombectomy procedure, and allow us to study the initial molecular response to ischemic stroke in the human condition in ways previously unavailable.

Abstract WMP113: Translational Evaluation of Acid/Base and Electrolyte Alterations in Acute Large Vessel Stroke

Background and Purpose: Monitoring for hypotension, hyperglycemia, hypoxia, and dehydration is key to reducing early death in stroke patients. Evaluation of physiological predictors of infarct volume and mortality may provide opportunities for effective interventions to improve outcomes. The purpose of this study is: 1) to describe and compare the predictive effects of venous blood gas (VBG) on infarct volume and mortality in acute stroke in rats; 2) and we have begun to collect arterial blood gas (ABG) to compare differences obtained proximal and distal to the occluded intracranial thrombi in acute ischemic stroke patients.

Methods: 3-month old Sprague-Dawey rats (n = 9) underwent permanent or transient middle cerebral artery occlusion (MCAO). Pre- and post-MCAO venous samples provided pH, pCO 2 , pO 2 , and electrolyte values (iCa 2+ , K + , and Na + ). Linear regression determined predictors of infarct volume from these values, and Cox regression analyzed VBG changes between tMCAO (n = 28) and pMCAO (n = 29) to determine predictors of mortality. We compared mean proximal and distal pH, pCO 2 , pO 2 , and electrolytes (iCa 2+ , K + , and Na + ) in stroke patients (n = 7) arterial samples using Wilcoxon Signed Ranks test.

Results: Animal studies demonstrated pH and iCa 2+ are predictors of infarct volume, but not mortality. After pMCAO (n = 9), change in pH or iCa 2+ significantly predicted infarct volume [F(1,7) = 7.351, β = -0.716, p = 0.03] and [F(1, 7) = 6.782, β = -0.701, p = 0.035]; as pH and calcium decreased, infarct volume increased. These variables explained 44% and 42% of the total variance in these models. In human patients (n = 7), there were significant differences in blood samples proximal and distal to the intracranial thrombus for pCO 2 (p = 0.018), HCO 3- (p = 0.028), iCa 2+ (p = 0.043), K + (p = 0.028), and Na + (p = 0.044).

Conclusions: In conclusion, there are acute changes in acid/base balance and electrolytes during stroke in rodent models and humans. In cross-species comparison ionized calcium changes were significant in both, with iCa 2+ changes predicting stroke volume in the rat model. These preliminary findings are novel, and warrant further exploration in human patients.

Intra-arterial verapamil post-thrombectomy is feasible, safe, and neuroprotective in stroke

Large vessel ischemic stroke represents the most disabling subtype. While t-PA and endovascular thrombectomy can recanalize the occluded vessel, good clinical outcomes are not uniformly achieved. We propose that supplementing endovascular thrombectomy with superselective intra-arterial (IA) verapamil immediately following recanalization could be safe and effective. Verapamil, a calcium channel blocker, has been shown to be an effective IA adjunct in a pre-clinical mouse focal ischemia model. To demonstrate translational efficacy, mechanism, feasibility, and safety, we conducted a group of translational experiments. We performed in vivo IA dose-response evaluation in our animal stroke model with C57/Bl6 mice. We evaluated neuroprotective mechanism through in vitro primary cortical neuron (PCN) cultures. Finally, we performed a Phase I trial, SAVER-I, to evaluate feasibility and safety of administration in the human condition. IA verapamil has a likely plateau or inverted-U dose-response with a defined toxicity level in mice (LD₅₀ 16-17.5 mg/kg). Verapamil significantly prevented PCN death and deleterious ischemic effects. Finally, the SAVER-I clinical trial showed no evidence that IA verapamil increased the risk of intracranial hemorrhage or other adverse effect/procedural complication in human subjects. We conclude that superselective IA verapamil administration immediately following thrombectomy is safe and feasible, and has direct, dose-response-related benefits in ischemia.

Interhospital Transfer Before Thrombectomy Is Associated With Delayed Treatment and Worse Outcome in the STRATIS Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke)

Supplemental Digital Content is available in the text.

Background:

Endovascular treatment with mechanical thrombectomy (MT) is beneficial for patients with acute stroke suffering a large-vessel occlusion, although treatment efficacy is highly time-dependent. We hypothesized that interhospital transfer to endovascular-capable centers would result in treatment delays and worse clinical outcomes compared with direct presentation.

Methods:

STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter, observational, single-arm study of real-world MT for acute stroke because of anterior-circulation large-vessel occlusion performed at 55 sites over 2 years, including 1000 patients with severe stroke and treated within 8 hours. Patients underwent MT with or without intravenous tissue plasminogen activator and were admitted to endovascular-capable centers via either interhospital transfer or direct presentation. The primary clinical outcome was functional independence (modified Rankin Score 0–2) at 90 days. We assessed (1) real-world time metrics of stroke care delivery, (2) outcome differences between direct and transfer patients undergoing MT, and (3) the potential impact of local hospital bypass.

Results:

A total of 984 patients were analyzed. Median onset-to-revascularization time was 202.0 minutes for direct versus 311.5 minutes for transfer patients (P<0.001). Clinical outcomes were better in the direct group, with 60.0% (299/498) achieving functional independence compared with 52.2% (213/408) in the transfer group (odds ratio, 1.38; 95% confidence interval, 1.06–1.79; P=0.02). Likewise, excellent outcome (modified Rankin Score 0–1) was achieved in 47.4% (236/498) of direct patients versus 38.0% (155/408) of transfer patients (odds ratio, 1.47; 95% confidence interval, 1.13–1.92; P=0.005). Mortality did not differ between the 2 groups (15.1% for direct, 13.7% for transfer; P=0.55). Intravenous tissue plasminogen activator did not impact outcomes. Hypothetical bypass modeling for all transferred patients suggested that intravenous tissue plasminogen activator would be delayed by 12 minutes, but MT would be performed 91 minutes sooner if patients were routed directly to endovascular-capable centers. If bypass is limited to a 20-mile radius from onset, then intravenous tissue plasminogen activator would be delayed by 7 minutes and MT performed 94 minutes earlier.

Conclusions:

In this large, real-world study, interhospital transfer was associated with significant treatment delays and lower chance of good outcome. Strategies to facilitate more rapid identification of large-vessel occlusion and direct routing to endovascular-capable centers for patients with severe stroke may improve outcomes.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02239640.

Abstract W MP6: SAVER I: Superselective Administration of VErapamil during Recanalization in Acute Ischemic Stroke. A Phase I Feasibility Study

Large vessel occlusive ischemic stroke results in high rates of morbidity and mortality. While intravenous t-PA and intra-arterial (IA) thrombectomy are mainstays in acute stroke therapy, clinical outcomes lag significantly behind improving rates of acute revascularization. Thus, there is a critical need for a novel adjunctive therapy to reduce stroke burden and to improve outcome. Previous neuroprotective drug studies failed due to long intervals between symptom onset and drug administration, lack of concordant thrombolytic revascularization, and lack of targeted administration to the affected vessel. Through a retro-engineered mouse model of large vessel stroke allowing concomitant recanalization and selective intra-arterial (IA) administration we previously evaluated verapamil, a calcium channel blocker (CCB) that is already safely injected intra-arterially (IA) for vasospasm. In this clinically relevant model, verapamil was highly neuroprotective when combined with vessel recanalization. Based on this data, we conducted a single-institution Phase I study to evaluate the feasibility and safety of superselective IA verapamil (10mg) administration immediately following mechanical thrombectomy. We collected information about demographics, location of the occlusion, last known normal time, time to and recanalization. Evaluation of CTA collateralization was performed using a previously a published grading scale (Souza et al. AJNR. 2012). The primary endpoint was symptomatic intracranial hemorrhage (ICH) within 24 hours post-procedure as defined by the Interventional Management Stroke (IMS) III Trial (Broderick et al. NEJM. 2013). Patients were monitored and graded at 3 months with the modified Rankin Score (mRS). Of the enrolled patients, none had a significant ICH, and none died as a direct result of the procedure. Clinical outcome results for patients were encouraging, and warrant further study. These results will be used to support a Phase II dose selection study.

Acute pancreatitis: value and impact of CT severity index

Acute pancreatitis is a disease with a broad spectrum of findings that varies in severity from mild interstitial or edematous pancreas to severe forms with significant local and systemic complications that are associated with a substantial degree of morbidity and mortality. Several scoring systems are used to assess the severity and predict the outcome and prognosis of acute pancreatitis. These include the Ranson, Acute Physiology And Chronic Health Evaluation II (APACHE II) and Glasgow scales. The CT severity index (CTSI) derived by Balthazar et al. has become widely used for description of CT findings in acute pancreatitis. The purpose of this project was to examine the current best evidence about regarding the effect of using a CTSI on patient outcome and its value in comparison with other widely used scoring systems.

Ischaemic stroke in children secondary to post varicella angiopathy

Varicella in childhood is a self-limiting disease, which usually follows a benign course. However, complications, although rare, may have serious consequences. Ischaemic stroke secondary to post varicella angiopathy is a well-described complication and is estimated to account for up to a third of all strokes in infants. We present three previously healthy children who presented to our centre with ischaemic cerebrovascular infarction due to varicella angiopathy. All three children first presented within six weeks after onset of varicella infection and had MRI changes characteristic of ischaemic stroke secondary to post varicella angiopathy. While one child made an excellent recovery being left with only a minor deficit, the remaining two children were left with considerable morbidity severely affecting quality of life. The varicella vaccine has been proven to be well tolerated, safe and effective. We conclude that varicella vaccination should be considered for inclusion in the vaccination schedule to prevent serious complications which while rare may have devastating consequences.