Thrombectomy Centre Research Articles

Direct to Thrombectomy.

Direct to Thrombectomy.

Global impact of COVID-19 on stroke care.

BackgroundThe COVID-19 pandemic led to profound changes in the organization of health care systems worldwide.AimsWe sought to measure the global impact of the COVID-19 pandemic on the volumes for mechanical thrombectomy, stroke, and intracranial hemorrhage hospitalizations over a three-month period at the height of the pandemic (1 March–31 May 2020) compared with two control three-month periods (immediately preceding and one year prior).MethodsRetrospective, observational, international study, across 6 continents, 40 countries, and 187 comprehensive stroke centers. The diagnoses were identified by their ICD-10 codes and/or classifications in stroke databases at participating centers.ResultsThe hospitalization volumes for any stroke, intracranial hemorrhage, and mechanical thrombectomy were 26,699, 4002, and 5191 in the three months immediately before versus 21,576, 3540, and 4533 during the first three pandemic months, representing declines of 19.2% (95%CI, −19.7 to −18.7), 11.5% (95%CI, −12.6 to −10.6), and 12.7% (95%CI, −13.6 to −11.8), respectively. The decreases were noted across centers with high, mid, and low COVID-19 hospitalization burden, and also across high, mid, and low volume stroke/mechanical thrombectomy centers. High-volume COVID-19 centers (−20.5%) had greater declines in mechanical thrombectomy volumes than mid- (−10.1%) and low-volume (−8.7%) centers (p < 0.0001). There was a 1.5% stroke rate across 54,366 COVID-19 hospitalizations. SARS-CoV-2 infection was noted in 3.9% (784/20,250) of all stroke admissions.ConclusionThe COVID-19 pandemic was associated with a global decline in the volume of overall stroke hospitalizations, mechanical thrombectomy procedures, and intracranial hemorrhage admission volumes. Despite geographic variations, these volume reductions were observed regardless of COVID-19 hospitalization burden and pre-pandemic stroke/mechanical thrombectomy volumes.

Abstract P503: Inter-Rater Reliability and Validity of Pre-Hospital Vision-Aphasia-Neglect Assessment for Triage of Patients With Suspected Large Vessel Occlusion: Analysis of Data From Three Comprehensive Stroke Centers in New Orleans (VAN NOLA Study)

Background: The Louisiana pre-hospital routing protocol for acute stroke patients is modeled after Mission Lifeline Stroke. The Vision-Aphasia-Neglect (VAN) assessment was adopted for large vessel occlusion (LVO) screening after education was provided to pre-hospital providers (EMS). We sought to establish the inter-rater reliability (IRR) of VAN between EMS and experienced stroke team members at comprehensive stroke centers (CSC) and assessed validity of EMS and CSC VAN. Methods: The EMS run reports were linked with stroke registries from three CSCs in New Orleans, Louisiana from 2/2019-7/2019. EMS-VAN was compared to that of CSCs in all patients who presented within 6 hours of last seen normal. Validity analyses were performed comparing EMS-VAN and CSC-VAN with radiologically confirmed (CTA) LVO as the gold standard. Kappa (k) and 95% confidence interval (CI) are reported as a measure of IRR. Likelihood of VAN non documentation by EMS and VAN discordance between EMS and CSC was determined as Odds Ratios (OR) and CI. Results: EMS documented VAN in 63.2% of stroke codes brought to CSCs. Advanced age (OR, CI: 1.02, 1.01 - 1.04) and pre-existing disability (OR, CI: 1.53, 1.32 - 1.76) increased the likelihood that VAN was not documented by EMS. Both EMS and CSC VAN assessments were documented for 166 patients Concordance was 66.9%; the k, CI was 0.35, 0.20 - 0.50. Discordance was more likely when EMS assessed a patient as positive than when assessed as negative, but no clinical predictor of discordance was identified. The accuracy of EMS-VAN was 60.2% for distinguishing LVO positive and negative patients; CSC-VAN was 65.5% accurate. Discussion: VAN assessment as performed by trained EMS providers had only fair correlation with experienced stroke team members. Further education is needed to increase the inter-rater reliability and accuracy of the VAN assessment in order to improve its utility in meeting the goal of routing patients with LVO to the thrombectomy centers.

Hub-and-spoke model for thrombectomy service in UK NHS practice

Mechanical thrombectomy is a highly effective but time dependent treatment for acute ischaemic stroke due to large vessel occlusion. In the UK, the national clinical guidelines for stroke and National Institute for Health and Care Excellence guidance endorses thrombectomy as an acute stroke treatment, and NHS England commissioned thrombectomy services. However, there are no UK 'real-world' data to verify the efficacy of the hub-and-spoke model in thrombectomy. There are currently 24 tertiary neuroscience centres in the UK that can provide thrombectomy treatment and many of these operate only within working hours. This study is the first to demonstrate that a hub-and-spoke thrombectomy service in routine UK 24/7 clinical practice is as effective and safe as in the setting of randomised controlled clinical trials. However, there are 9.3% of patients accepted for transfer to the thrombectomy centre who did not proceed to thrombectomy, mostly due to delays. Fifty-three per cent of thrombectomy cases were performed outside of standard working hours when transfer delays were increased. A 24/7 thrombectomy service is needed to maximise the benefit to all suitable patients. Measures, including improving workflow and optimising work forces, are needed to minimise the delays and continue to improve the service.

Regarding thrombectomy centre volumes and maximising access to thrombectomy services for stroke in England: A modelling study and mechanical thrombectomy for acute ischaemic stroke: An implementation guide for the UK.

Regarding thrombectomy centre volumes and maximising access to thrombectomy services for stroke in England: A modelling study and mechanical thrombectomy for acute ischaemic stroke: An implementation guide for the UK.

Letter by Kallmünzer et al Regarding Article, “Safety of Intravenous Thrombolysis Among Patients Taking Direct Oral Anticoagulants: a Systematic Review and Meta-Analysis”

HomeStrokeVol. 51, No. 7Letter by Kallmünzer et al Regarding Article, “Safety of Intravenous Thrombolysis Among Patients Taking Direct Oral Anticoagulants: a Systematic Review and Meta-Analysis” Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyRedditDiggEmail Jump toFree AccessLetterPDF/EPUBLetter by Kallmünzer et al Regarding Article, “Safety of Intravenous Thrombolysis Among Patients Taking Direct Oral Anticoagulants: a Systematic Review and Meta-Analysis” Bernd Kallmünzer, MD, Michael Pott, MD and Stefan Schwab, MD Bernd KallmünzerBernd Kallmünzer https://orcid.org/0000-0003-3552-6742 Department of Neurology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Germany (B.K., S.S.). Department of Neurology, Klinikum Bayreuth GmbH, Bayreuth, Germany. Search for more papers by this author , Michael PottMichael Pott Search for more papers by this author and Stefan SchwabStefan Schwab Department of Neurology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Germany (B.K., S.S.). Department of Neurology, Klinikum Bayreuth GmbH, Bayreuth, Germany. Search for more papers by this author Originally published16 Jun 2020https://doi.org/10.1161/STROKEAHA.120.029631Stroke. 2020;51:e130–e131To the Editor:With great interest we read the article “Safety of Intravenous Thrombolysis Among Patients Taking Direct Oral Anticoagulants” by Shahjouei et al.1 Before the use of rtPA in patients on oral anticoagulation, it seems reasonable to use antidots for anticoagulation reversal. Andexanet alfa, a recombinant form of the human factor Xa, rapidly reduces the anticoagulatory effect of factor Xa inhibitors2 and was recently approved for emergent reversal of oral anticoagulation in patients on treatment with apixaban or rivaroxaban.Recently, a 77-year-old woman presented to a German hospital with an acute ischemic stroke causing serious left-sided hemiparesis and dysarthria 2 hours after symptom onset. Computed tomography angiography confirmed an occlusion of the right medial cerebral artery at the proximal segment. The condition demanded an immediate treatment with alteplase followed by the transfer to a neurovascular center for mechanical thrombectomy. The patient suffered from permanent atrial fibrillation and used apixab (5 mg b.i.d.) for the prevention of thromboembolism. She had taken the last dose of apixaban 3 hours before admission. A chromogenic assay found the calibrated antifactor Xa activity being elevated to 188 ng/mL, which formally contradicted the use of recombinant tissue plasminogen activitor (r-tPA). Therefore, it was decided to reverse the effect of apixaban before intravenous thrombolysis: The patient received an intravenous bolus of 400 mg andexanet alfa at a target rate of 30 mg/minute. A continuous infusion of 480 mg followed for 2 hours, resulting in a total dose of 880 mg andexanet alfa. Treatment with alteplase was initiated as soon as the andexanet alfa bolus had been administered. r-tPA total dose was 90 mg (9 mg bolus followed by a 1-hour infusion of 81 mg) and the patient started immediate transfer to the thrombectomy center. On arrival, her neurological symptoms had markedly improved. The MCA occlusion showed complete recanalization before endovascular treatment. Ten hours after symptom onset, the anti-factor Xa activity had spontaneously increased to 277 ng/mL and remained elevated during the first days. No hemorrhagic complications occurred. The estimated glomerular filtration rate was 58 mL/minute.The use of alteplase in patients on treatment with direct oral anticoagulants has not been firmly established.1 For dabigatran, it seems feasible to reverse the anticoagulant by idarucizumab before the initiation of intravenous thrombolysis.3 Unlike idarucizumab, the characteristics of andexanet alfa result in an incomplete and only transient reduction of the antithrombotic activity.2,4 Consistently, a rebound even beyond the level on admission occurred in this patient at 10 hours after symptom onset. As the frequency of hemorrhagic complications raises with higher anticoagulant peak levels,5 this secondary increase will caution the clinician about an elevated risk of r-tPA associated bleeding, despite the use of Andexanet alfa.AcknowledgmentsWe thank Professor Erwin Strasser, Department for Hemostaseology and Transfusion Medicine, University Hospital Erlangen, for the measurements of the anti-Factor Xa Activitity.DisclosuresDr Kallmünzer reports speaker honoraria from BMS Pfizer, Daiichi Sankyo, Bayer AG and Medtronic, outside the submitted work. Dr Schwab reports speaker honoria and travel grants from Boehringer Ingelheim, Pfizer, Daiichi Sankyo. The other authors report no conflicts.FootnotesFor Disclosures, see page e130.

Delayed Thrombectomy Center Arrival is Associated with Decreased Treatment Probability.

Endovascular thrombectomy (EVT) is effective in reducing disability in selected patients with stroke and large vessel occlusion (LVO), but access to this treatment is suboptimal. We examined the proportion of patients with LVO who did not receive EVT, the reasons for non-treatment, and the association between time from onset and probability of treatment. We conducted a retrospective cohort study of consecutive patients with acute stroke and LVO presenting between January 2017 and June 2018. We used multivariable log-binomial models to determine the association between time and probability of treatment with and without adjustment for age, sex, dementia, active cancer, baseline disability, stroke severity, and evidence of ischemia on computerized tomography. We identified 256 patients (51% female, median age 74 [interquartile range, IQR 63.5, 82.5]), of whom 59% did not receive EVT. The main reasons for not treating with EVT were related to occlusion characteristics or infarct size. The median time from onset to EVT center arrival was longer among non-treated patients (218 minutes [142, 302]) than those who were treated (180 minutes [104, 265], p=0.03). Among patients presenting within 6 hours of onset, the relative risk (RR) of receiving EVT decreased by 3% with every 10-minute delay in arrival to EVT center (adjusted RR 0.97 CI95 [0.95, 0.99]). This association was not found in the overall cohort. The proportion of patients with acute stroke and confirmed LVO who do not undergo EVT is substantial. Minimizing delays in arrival to EVT center may optimize the delivery of this treatment.

The cost of providing mechanical thrombectomy in the UK NHS: a micro-costing study

The clinical efficacy and cost-effectiveness of mechanical thrombectomy (MT) for the treatment of large vessel occlusion stroke is well established, but uncertainty remains around the true cost of delivering this treatment within the NHS. The aim of this study was to establish the cost of providing MT within the hyperacute phase of care and to explore differences in resources used and costs across different neuroscience centres in the UK. This was a multicentre retrospective study using micro-costing methods to enable a precise assessment of the costs of MT from an NHS perspective. Data on resources used and their costs were collected from five UK neuroscience centres between 2015 and 2018. Data were collected on 310 patients with acute ischaemic stroke treated with MT. The mean total cost of providing MT and inpatient care within 24 hours was £10,846 (95% confidence interval (CI) 10,527-11,165) per patient. The main driver of cost was MT procedure costs, accounting for 73% (£7,943; 95% CI 7,649-8,237) of the total 24-hour cost. Costs were higher for patients treated under general anaesthesia (£11,048; standard deviation (SD) 2,654) than for local anaesthesia (£9,978; SD 2,654), mean difference £1,070 (95% CI 381-1,759; p=0.003); admission to an intensive care unit (ICU; £12,212; SD 3,028) against for admission elsewhere (£10,179; SD 2,415), mean difference £2,032 (95% CI 1,345-2,719; p<0001).The mean cost within 72 hours was £12,440 (95% CI 10,628-14,252). The total costs for the duration of inpatient care before discharge from a thrombectomy centre was £14,362 (95% CI 13,603-15,122). Major factors contributing to costs of MT for stroke include consumables and staff for intervention, use of general anaesthesia and ICU admissions. These findings can inform the reimbursement, provision and strategic planning of stroke services and aid future economic evaluations.

First line transradial access for posterior circulation stroke intervention; initial 12-month experience at a high volume thrombectomy center

BackgroundThe Neurointerventional Surgery Standards and Guidelines Committee has advocated the use of transradial access in the setting of posterior circulation stroke intervention, however there is a paucity of published data on this approach. The purpose of this study is to present 12-months of prospectively collected data from a high volume thrombectomy center following the adoption of a first line transradial approach for posterior circulation stroke intervention. MethodsA range of data on patient characteristics, procedural metrics, complications and outcomes was prospectively collected between August 2018 - August 2019 following the adoption of first line transradial access for posterior circulation stroke intervention at a high volume thrombectomy center. ResultsTransradial access was successful in 22/23 cases (96%), median arteriotomy to reperfusion time was 24 min (IQR 18–40), good angiographic outcome (mTICI 2b-3) was achieved in all cases and good clinical outcome (mRs 0–2) was achieved in 61% of cases. No intracranial or radial artery access site complications occurred. ConclusionThe fast procedure times, excellent outcomes and low complication rates achieved in this prospective 12-month study indicate that transradial access is a viable first line strategy in posterior circulation stroke intervention.

Abstract TP255: Tackling Door in-Door Out Through a Statewide Initiative

Background: The AHA/ASA has determined thrombectomy is standard-of-care up to 24 hours after last seen normal (LSN) for ischemic stroke patients with anterior circulation large vessel occlusion (LVO), provided the perfusion imaging profile meets criteria. Many patients require secondary transfer to access thrombectomy centers. The door in-door out (DIDO) is a target for process improvement. Methods: The Louisiana Emergency Response Network (LERN)’s stroke system of care was initiated in 2010. Submission of quarterly emergency department stroke data to LERN was voluntary as of Q1 2014 and was mandated as of Q1 2018 for hospitals attesting to Acute Stroke Ready Hospital (ASRH) capability. Sites across the state were invited to pilot expanded variable in order to assess LVO screening and baseline DIDO for patients with LVO. Results: Of 56 ASRHs, 34 sites submitted one or more quarters of data during the pilot phase contributing a total of 1808 cases. LVO screening was performed in 992 (54.9%) cases; 172 (17.3%) were LVO screened positive. VAN was used in 75.6% of LVO positive patients and CTA was used in 20.3%. Most patients (71.3%) arrived via ambulance. The median NIHSS in LVO positive patients was 12 (IQR 5-20). Transfer time was available in 114 (66%) LVO positive patients; median DIDO was 146 minutes (IQR 89-243 minutes). Transfer request time was available in 30 (17.4%) of LVO positive patients; median interval from transfer request to departure was 47 minutes (IQR 31-65 minutes). Discussion: Given that most patients with ischemic stroke caused by LVO will not present initially to a thrombectomy center, DIDO must be minimized to preserve penumbra and maximize likelihood of eligibility for thrombectomy when the thrombectomy center is accessed. LERN’s pilot LVO screening study established a baseline from which DIDO is a necessary target for intervention. Only 25% of LVO positive patients were transferred with DIDO less than 90 minutes. LERN’s initial goal is to shift the median DIDO to 90 minutes. Participation in the expanded variables targeting LVO screening and DIDO was mandated by LERN effective Q3 2018.

Abstract 105: Impact of the Extended Window Mechanical Thrombectomy on Tele Stroke Call Volume in the Post-DAWN and DEFUSE -3 Era

Introduction: Recently, two randomized controlled trials proved the safety and efficacy of mechanical thrombectomy in patients presenting up to 24 hours from symptom onset. While the number of patients receiving mechanical thrombectomy has increased following the publication of the extended time window trials, the literature on acute stroke calls over telestroke is relatively scant. In this study we evaluate the volume of telestroke calls, rate of transfers to the thrombectomy center and MT receipt before and after the extended window MT trials publication. Methods: We interrogated the prospectively collected data from a major telestroke network in Southeast the United States to include patients who received a telestroke consult between January 2015 and July 2019. We compared the demographical and clinical characteristics and the outcomes between patients who presented before and after the publication of the extended window mechanical thrombectomy trials. Results: Total of 7,438 patients were evaluated during the study period. Of those, 3392 were after February 2018. There was no difference in age, race, or sex between the two groups (table 1). Patients in the post extended window group had lower National Institute of Health stroke scale (NIHSS) on presentation (3 vs. 4, P&lt;0.001), had longer symptom-onset to door time (123 vs. 85 min, P&lt;0.001), and were more likely to present with stroke mimics (41% vs. 35.3%, P&lt;0.001).Despite this increase in the number of consults per month (190 vs. 103, P&lt;0.001) in the post-DAWN era, there was similar rates of patients eventually receiving MT (3.9% vs. 3.8%, p=0.849) Conclusion: The number of telestroke consults almost doubled since the publication of the extended thrombectomy trials without increase in the rate of MT receipt. These findings have important operational implications for hospitals implementing telestroke call coverage.

Abstract WP345: Feasibility of Monitoring Door in Door Out Times Across a 14 Hospital Telemedicine Supported Stroke System of Care

Background: Door-in-door-out time (DIDO) is an established driver of outcome in ischemic stroke patients who initially present to a Primay Stroke Center (PSC) and require transfer for endovascular intervention. In 2019, the Joint Commission required monitoring of DIDO as part of its STK-OP measure. Given the importance of rapidly transferring ischemic stroke patients, we embarked to create a monitoring tool to help assess the areas of delay in a 14 hospital telemedicine supported stroke system. Methods: A monitoring system was designed using PowerBI™ and Microsoft Suite™ products that models various data sources for consumption and action. Separate data queries from various sources were entered into one report using the Office365™ suite and Power Query Editor™ in PowerBI™. The resulting data model was then reorganized and programmed into a PowerBI™ report that can be shared throughout the organization. Results: The report allowed region-wide or hospital specific evaluation of several time based transfer metrics, including: door to initial call to transfer center, transfer center contact to neurointerventional physician accept time, accept time to ambulance arrival, ambulance arrival to ambulance departure and travel time to thrombectomy center. The largest areas of delays identified were door to initial call to transfer center and time of ambulance arrival to spoke to departure from spoke. The tool also allowed the separation of the STK-OP measure into ischemic stroke, intracerebral hemorrhage or sub-arachnoid hemorrhage. The assessment of these time metrics at a regional and individual hospital level permitted us to create a plan to focus on the greatest areas of delay to further decrease our transfer times. Conclusion: Modern data software may be leveraged by stroke programs to help assess the specific time metrics causing delay in DIDO, which could then further assist in focused quality improvement of these metrics.

PND83 ACCESS TO INTRAVENOUS TISSUE-LIKE PLASMINOGEN ACTIVATOR (IV TPA) THERAPY AND MECHANICAL THROMBECTOMY (MT) FOR PATIENTS WITH ACUTE ISCHEMIC STROKE IN HUNGARY

Since 2002, IV tPA has been approved in Europe for use in acute stroke, which in 2015 was complemented by MT. These acute stroke treatments have significantly improved patient outcomes. However, in ischemic stroke, access to care requires adequate management of patient pathways. The objective of our study was to assess the extent by which acute ischemic stroke patients access IV tPA and MT treatment options in Hungary. Data was retrieved from the Pulvita Healthcare Data Warehouse operated by National Healthcare Services Center (AEEK) and a dedicated acute ischemic stroke registry, in which data was provided by three thrombectomy centers (University of Pécs, University of Debrecen and University of Szeged). Estimations were made regarding the actual number of acute ischemic stroke patients, number and ratio of patients treated with IV tPA or MT. Between the 1st and 3rd quarter of 2018, 2,426 patients (8.3% of all ischemic strokes) were treated with iv-tPA and/or MT in Hungary. Based on the data of three thrombectomy centres, 21.2% of the patients received MT alone, 75.0% received IV tPA alone, and 3.8% received both treatments. 15.3% of all MT were performed after IV tPA. 25.3% of all MTs were performed within 4.5 hours without IV tPA, while 57.8% were between 4.5 and 6 hours and 1.4% beyond 6 hours of the onset of stroke event. Our study shows that the access to and delivery of IV tPA and MT are relatively low in Hungary, especially when compared to Western European countries, where the proportion of ischaemic patients receiving IV tPA was 18% in Austria in 2011, and 16.7% in France in 2014–2015. These findings indicate a major opportunity for optimizing the stroke care pathway according to the most recent treatments and reduce ischaemic stroke mortality.

Clinical and Imaging Parameters Associated With Hyperacute Infarction Growth in Large Vessel Occlusion Stroke.

Background and Purpose- Large vessel occlusion stroke leads to highly variable hyperacute infarction growth. Our aim was to identify clinical and imaging parameters associated with hyperacute infarction growth in patients with an large vessel occlusion stroke of the anterior circulation. Methods- Seven hundred twenty-two consecutive patients with acute stroke were prospectively included in our monocentric stroke registry between 2009 and 2017. We selected all patients with a large vessel occlusion stroke of the anterior circulation, documented times from symptom onset, and CT perfusion on admission for our analysis (N=178). Ischemic core volume was determined with CT perfusion using automated thresholds. Hyperacute infarction growth was defined as ischemic core volume divided by times from symptom onset, assuming linear progression during times from symptom onset to imaging on admission. For collateral assessment, the regional leptomeningeal collateral score (rLMC) was used. Clinical data included the National Institutes of Health Stroke Scale score on admission and cardiovascular risk factors. Regression analysis was performed to adjust for confounders. Results- Median ischemic core volume was 34.4 mL, and median hyperacute infarction growth was 0.27 mL/min. In regression analysis including age, sex, National Institutes of Health Stroke Scale, clot burden score, diabetes mellitus, smoking, hypercholesteremia, hypertension, Alberta Stroke Program Early CT Score, and rLMC scores, only the rLMC score had a significant, independent association with hyperacute infarction growth (adjusted β=-0.35; P<0.001). Trichotomizing patients by rLMC scores yielded 65 patients with good (rLMC >15), 67 with intermediate (rLMC 11-15) and 46 with poor collaterals (rLMC <11) with an infarction growth of 0.17 mL/min, 0.26 mL/min, and 0.41 mL/min, respectively. Conclusions- Hyperacute infarction growth strongly depends on collaterals. In primary stroke centers, hyperacute infarction growth may be extrapolated to estimate the stroke progression during transfer times to thrombectomy centers and to support decisions on which patients to transfer.

Outcomes after Thrombectomy in Belfast: Mothership and Drip-and-Ship in the Real World

Background: Mechanical thrombectomy has revolutionised the treatment of acute ischaemic stroke due to large vessel occlusion. It is well recognised that patients are more likely to benefit when reperfusion happens quickly, however, there is uncertainty as to how best to deliver this service. Objectives: To compare outcomes of patients in Northern ­Ireland who underwent thrombectomy via direct admission to the single endovascular centre (mothership [MS]) with those transferred from primary stroke centres (drip-and-ship [DS]). Methods: Analysis was conducted on the records of all patients who underwent thrombectomy from January 2014 to December 2017 inclusive. The primary outcome measure was 3 months functional independence (modified Rankin Score [mRS] 0–2). Secondary outcome measures were full recovery (mRS 0) at 3 months, symptomatic intracranial haemorrhage (sICH) rates and mortality rates. Results: Two hundred fourteen patients underwent thrombectomy (MS 124, DS 90). Patients in the MS group were older (median 73 vs. 70 years, p = 0.026), but there was no significant difference in baseline National Institutes of Health Stroke Scale (median 15 MS vs. 16.5 DS, p = 0.162) or thrombolysis rates (41.9% MS vs. 54.4% DS, p = 0.070) between the groups. Time from stroke onset to arrival at thrombectomy centre was shorter in the MS group (median 71 vs. 218 min, p < 0.001) but door to groin puncture time was shorter in the DS group (median 30 vs. 60 min, p < 0.001). There was no significant difference in 3 months functional independence (51.6% MS vs. 62.2% DS, p = 0.123), or in the secondary outcome measures of full recovery (21.8% MS vs. 12.2% DS, p = 0.071), sICH (MS 0.8%, DS 4.4%, p = 0.082) and mortality (MS 24.2%, DS 20.0%, p = 0.468). Conclusions: Our analysis showed similar outcomes after thrombectomy in the MS and DS groups. For patients potentially eligible for thrombectomy, rapid access to the endovascular centre is essential to optimise both the number of patients treated and the outcomes achieved.

The Extended Treatment Window's Impact on Emergency Systems of Care for Acute Stroke.

The window for acute ischemic stroke treatment was previously limited to 4.5 hours for intravenous tissue plasminogen activator and to 6 hours for thrombectomy. Recent studies using advanced imaging selection expand this window for select patients up to 24 hours from last known well. These studies directly affect emergency stroke management, including prehospital triage and emergency department (ED) management of suspected stroke patients. This narrative review summarizes the data expanding the treatment window for ischemic stroke to 24 hours and discusses these implications on stroke systems of care. It analyzes the implications on prehospital protocols to identify and transfer large-vessel occlusion stroke patients, on issues of distributive justice, and on ED management to provide advanced imaging and access to thrombectomy centers. The creation of high-performing systems of care to manage acute ischemic stroke patients requires academic emergency physician leadership attentive to the rapidly changing science of stroke care.

Abstract 159: Baseline Perfusion Imaging Collateral Scores Predict Infarct Growth in DEFUSE 3

Background: High relative cerebral blood volume (rCBV) within the ischemic lesion and a low hypoperfusion intensity ratio (HIR) predict good collateral vessel status and correlate with infarct growth and functional outcome in early window patients with large vessel anterior circulation occlusions. Their performance in predicting clinical and radiologic outcome has not been assessed in late presenting patients. We hypothesized that favorable baseline HIR and rCBV profiles would predict less infarct growth at 24 hours in late presenting (6-16h), non-reperfused patients in DEFUSE 3. Methods: Non-reperfused patients in both arms of DEFUSE 3 were included. Baseline ischemic core, Tmax &gt;6s, and Tmax &gt;10s perfusion lesion volumes were calculated with RAPID software; 24h infarct volumes were manually determined from DWI or CT. Substantial infarct growth was defined as a &gt;25mL increase between baseline ischemic core and 24h infarct volume. HIR was defined as the proportion of the Tmax &gt;6s lesion with Tmax &gt;10s delay; rCBV was calculated by RAPID from the mean CBV values within the Tmax &gt;6s lesion compared to regions of normal CBV. Functional independence was defined as a modified Rankin score of 0-2. Results: Eighty-four patients with baseline perfusion imaging were included. ROC analysis showed that HIR &gt;0.34 (AUC=0.68) and rCBV &lt;0.74 (AUC=0.72) optimally predicted substantial infarct growth at 24h. Median growth was 23.4 versus 73.2mL with the HIR threshold of 0.34 (p=0.005), and 24.3 versus 58.7mL with the rCBV threshold of 0.74 (p=0.004). If baseline HIR and rCBV were both favorable, median growth was 21.7mL, 40.9mL if one was favorable, and 108.2mL if both were unfavorable (p=&lt;0.001). Baseline HIR and rCBV were not associated with functional outcome at 90 days, though baseline Tmax &gt;10s volume was significantly smaller in functionally independent patients (p=0.04). Conclusion: Perfusion collateral scores (HIR and rCBV) forecast infarct growth in late presenting, non-reperfused ischemic stroke patients. These parameters may be useful for guiding transfer decisions, such as need for repeat imaging on arrival to a thrombectomy center, and may help identify slow progressing patients more likely to have persistent salvageable ischemic tissue beyond 24 hours.

OP47 Need For New Thrombectomy Centers? A Practical Decision Framework

IntroductionStroke is a major contributor to mortality, disability and long-term use of healthcare services. As for all chrono-dependant conditions, clinical results are associated with timely access to appropriate care. Thrombectomy (EVT) is an effective treatment for large vessel occlusions, but can only be provided in highly-specialized centers by experienced personnel. We sought to develop a framework to aid decision-making on the appropriateness of opening new EVT centers in Québec, Canada.MethodsData sources included provincial administrative healthcare databases, population density statistics, field evaluation of Québec's four existing EVT care networks, and literature review concerning structural and performance criteria for EVT centers. We consulted EVT clinical teams, interdisciplinary stroke experts, patients, professional association representatives, healthcare managers and decision-makers.ResultsAccess to EVT is suboptimal in all 17 regions of Québec, with virtually no access in remote areas. Results of key performance indicators indicated favorable treatment delays after arrival at the EVT center. However, door-to-needle and door-in-door-out times were long for patients transferred from non-EVT centers. High use of ambulances indicated the potential to transport patients to the most appropriate center. In light of ‘real world’ results and other sources of information, the need for a new EVT center should consider the following criteria: sub-optimal EVT access within the region; transport time to an existing EVT center &gt;1 hour; expected patient volume within 2 hours of transport; impact on volume of existing programs; availability of long-term financial support; availability of a critical mass of neurointerventionists, vascular neurologists, and neurosurgeons; demonstrated quality of stroke care; and, presence of a stroke unit.ConclusionsThe triangulation of literature, clinician experience and the Québec context enriched the evaluation process. Furthermore, this facilitated the development of a framework that was broadly applicable across regions to the real-world setting of decision-making in a complex system of care.

Imaging in acute ischemic stroke using automated postprocessing algorithms

There are several automated analytical methods to detect thromboembolic vascular occlusions, the infarct core and the potential infarct-endangered tissue (tissue at risk) by means of multimodal computed tomography (CT) and magnetic resonance imaging (MRI). The infarct core is more reliably visualized by diffusion-weighted imaging (DWI) MRI or CT perfusion than by native CT. The extent of tissue at risk and endangerment can only be estimated; however, it seems essential whether "tissue at risk" actually exists. To ensure consistent patient care, uniform imaging protocols should be acquired in the referring hospital and thrombectomy center and the collected data should be standardized and automatically evaluated and presented. Whether patients with alarge infarct core and with or without tissue at risk or patients with large vessel occlusion (LVO) but low NIHSS benefit from thrombectomy has to be evaluated in controlled clinical trials using standardized imaging protocols. Apromising, potentially time-saving approach is also native CT and CT angiography using aflat-panel detector angiography system for assessment of vessel occlusion and leptomeningeal collaterals.

Drip and ship versus direct to endovascular thrombectomy: The impact of treatment times on transport decision-making.

In ischaemic stroke care, fast reperfusion is essential for disability free survival. It is unknown if bypassing thrombolysis centres in favour of endovascular thrombectomy (mothership) outweighs transport to the nearest thrombolysis centre for alteplase and then transfer for endovascular thrombectomy (drip-and-ship). We use conditional probability modelling to determine the impact of treatment times on transport decision-making for acute ischaemic stroke. Probability of good outcome was modelled using a previously published framework, data from the Irish National Stroke Register, and an endovascular thrombectomy registry at a tertiary referral centre in Ireland. Ireland was divided into 139 regions, transport times between each region and hospital were estimated using Google's Distance Matrix Application Program Interface. Results were mapped using ArcGIS 10.3. Using current treatment times, drip-and-ship rarely predicts best outcomes. However, if door to needle times are reduced to 30 min, drip-and-ship becomes more favourable; even more so if turnaround time (time from thrombolysis to departure for the endovascular thrombectomy centre) is also reduced. Reducing door to groin puncture times predicts better outcomes with the mothership model. This is the first case study modelling pre-hospital transport for ischaemic stroke utilising real treatment times in a defined geographic area. A moderate improvement in treatment times results in significant predicted changes to the optimisation of a national acute stroke patient transport strategy. Modelling patient transport for system-level planning is sensitive to treatment times at both thrombolysis and thrombectomy centres and has important implications for the future planning of thrombectomy services.