Interventional Stroke Therapy Research Articles

Unfavorable neurological long-term outcome despite eTICI 3 – What are the predictors?

PurposeInterventional stroke therapy has become standard treatment for patients with acute ischemic strokes. Complete reperfusion (eTICI 3) portrays the best possible technical outcome. The purpose of this study was to determine possible predictors for an unfavorable neurological long-term outcome (mRS 3–6) despite achieving the best possible treatment success. MethodsWe evaluated 122 patients with stroke in the anterior circulation and complete reperfusion after mechanical thrombectomy (MT) between May 2010 and March 2020. We performed a binary logistic regression analysis with patient baseline data, stroke severity, comorbidities, premedication and treatment information as independent variables. Results50 of the 122 patients included in our study showed a poor clinical outcome after 90 days (41 %). Multivariable logistic regression analysis showed that older age (p = 0.033), higher admission NIHSS (p=0.009), lower admission ASPECTS (p=0.005), a pre-existing cardiovascular disease (p=0.017), and multiple passes for complete reperfusion (p=0.030) had an independent impact on unfavorable outcome. ConclusionsOlder age, higher NIHSS upon admission, lower ASPECTS upon admission, cardiovascular comorbidities and multiple passes for complete reperfusion are predictors for poor neurological long-term outcome despite complete reperfusion.

Flow control in the middle cerebral artery during thrombectomy: the effect of anatomy, catheter size and tip location

BackgroundCatheter size, location and circle of Willis anatomy impact the flow conditions during interventional stroke therapy. The aim of the study was to systematically investigate the influence of these factors...

Advances in Stroke: Treatments-Interventional.

Advances in Stroke: Treatments-Interventional.

Multi-view iterative random walker for automated salvageable tissue delineation in ischemic stroke from multi-sequence MRI

Background and objectiveNon-invasive and robust identification of salvageable tissue (penumbra) is crucial for interventional stroke therapy. Besides identifying stroke injury as a whole, the ability to automatically differentiate core and penumbra tissues, using both diffusion and perfusion magnetic resonance imaging (MRI) sequences is essential for ischemic stroke treatment. MethodA fully automated and novel one-shot multi-view iterative random walker (MIRW) method with an automated injury seed point detection is developed for lesion delineation. MIRW utilizes the heirarchical decomposition of multi-sequence MRI physical properties of the underlying tissue within the lesion to maximize the inter-class variations of the volumetric histogram to estimate the probable seed points. These estimates are further utilized to conglomerate the lesion estimations iteratively from axial, coronal and sagittal MRI volumes for a computationally efficient segmentation and quantification of salvageable and necrotic tissues from multi-sequence MRI. ResultsComprehensive experimental analysis of MIRW is performed on three challenging adult(sub-)acute ischemic stroke datasets using performance measures like precision, sensitivity, specificity and Dice similarity score (DSC), which are computed with respect to the manual ground-truth. Comparison with existing methodsMIRW method resulted in a high DSC of 83.5% in a very less computational time of 98.23 s/volume, which is a significant improvement on the ISLES benchmark dataset for penumbra detection, compared to the state-of-the-art techniques. ConclusionQuantitative measures demonstrate the promising potential of MIRW for computational analysis of adult stroke and quantifying penumbra in stroke patients which is essential for selecting the good candidates for recanalization.

Abstract P814: Complex Movement Representations of Mouse Motor Cortex After Experimental Stroke

Stroke injury and incomplete long-term stroke recovery remain key health issues in the United States and world-wide. We seek to help identify cellular dysfunction of the motor cortex after stroke, and its possible circuit remodeling during stroke recovery, since this structure is heavily implicated in this biology. We propose to measure evoked motor responses during long-train intracortical microstimulation (LT-ICMS) of motor cortex in the mouse as a method to identify the functional organization of this structure and plasticity following experimental stroke that relates to functional recovery. This work is one of the first to use LT-ICMS in mice after experimental stroke and it is employed in this study because it evokes complex, multi-joint forelimb movements that may match the temporal activity patterns of motor cortical cells during volitional movement and relate to skilled motor behavior. Permanent stroke injury is induced here using photothrombotic occlusion of the distal middle cerebral artery (MCAo) using Rose Bengal dye and green laser photostimulation. Skilled motor behavior is tested using the single pellet reaching task. Each mouse completes 30 days of post-injury or sham-injury single pellet reaching that is followed by an evaluation of cortical forelimb movement representation using LT-ICMS and then histological testing of lesion size and location. LT-ICMS is delivered as 500 millisecond trains of biphasic 200 microsecond pulses (delivered at 333 Hz) via a platinum/iridium microelectrode. The microelectrode is applied to test sites across the motor cortex (354 micron spacing) that are each at a depth of 800 microns. Evoked movements to LT-ICMS are quantified using high-speed video kinematic tracking of the forelimb. Experimental blind conditions are maintained until study completion. Statistics are then used to relate outcomes of behavioral reaching, LT-ICMS, and lesion characteristics. Collectively, the goal of this project is to understand whether (and how) complex movement representations derived by LT-ICMS change during stroke recovery in order to guide rehabilitative and interventional stroke therapies.

Delineation of Ischemic Core and Penumbra Volumes from MRI using MSNet Architecture.

Medical image analysis tasks like segmentation and detection of injury involving manual interventions usually suffers from high inter-observer variabilities. To carry them out efficiently, various deep neural networks have been proposed recently as they provide much higher and reliable performance than the traditional image processing and manual segmentation methods. Non-invasive and robust quantification of salvageable tissue in acute ischemic stroke i.e., the ischemic penumbra, is critical for interventional stroke therapy. This paper proposes a Multi- Sequence Network (MSNet) architecture for this task. In this architecture, the information from multiple sequences are combined for identification and segmentation of core and penumbra (salvageable tissue) regions of ischemic stroke lesions and was tested on multisequence MRI ischemic lesion dataset of ISLES015. Performance of the proposed architecture, in terms of dice similarity coefficient, sensitivity and specificity are found to be 0.68, 0.805 and 0.99 respectively for the core of the lesion and 0.69, 0.949 and 0.964 respectively for the penumbra region.

Helistroke: neurointerventionalist helicopter transport for interventional stroke treatment: proof of concept and rationale

Background and purposeIt is increasingly recognized that time is one of the key determinants in acute stroke outcome when interventional stroke therapy is applied. With increasing device efficacy and understanding...

ERic Acute StrokE Recanalization: A study using predictive analytics to assess a new device for mechanical thrombectomy.

Aim and hypothesis Using a new study design, we investigate whether next-generation mechanical thrombectomy devices improve clinical outcomes in ischemic stroke patients. We hypothesize that this new methodology is superior to intravenous tissue plasminogen activator therapy alone. Methods and design ERic Acute StrokE Recanalization is an investigator-initiated prospective single-arm, multicenter, controlled, open label study to compare the safety and effectiveness of a new recanalization device and distal access catheter in acute ischemic stroke patients with symptoms attributable to acute ischemic stroke and vessel occlusion of the internal cerebral artery or middle cerebral artery. Study outcome The primary effectiveness endpoint is the volume of saved tissue. Volume of saved tissue is defined as difference of the actual infarct volume and the brain volume that is predicted to develop infarction by using an optimized high-level machine learning model that is trained on data from a historical cohort treated with IV tissue plasminogen activator. Sample size estimates Based on own preliminary data, 45 patients fulfilling all inclusion criteria need to complete the study to show an efficacy >38% with a power of 80% and a one-sided alpha error risk of 0.05 (based on a one sample t-test). Discussion ERic Acute StrokE Recanalization is the first prospective study in interventional stroke therapy to use predictive analytics as primary and secondary endpoint. Such trial design cannot replace randomized controlled trials with clinical endpoints. However, ERic Acute StrokE Recanalization could serve as an exemplary trial design for evaluating nonpivotal neurovascular interventions.

Imaging predictors of procedural and clinical outcome in endovascular acute stroke therapy

Acute stroke affects 795,000 people per year in the United States, and eighty-seven percent of these represent ischemic stroke. New level I evidence has created a need for consistent, effective and rapid triage of stroke patients to properly select those who will most benefit from endovascular stroke therapy. This review highlights anatomical factors and imaging signs that are prognostic with respect to stroke outcome and which could aid in the selection of patients that could most benefit from interventional stroke therapies, as well as exclude patients from therapy who are at a high risk of complication.

Abstract W P305: Processes Trends and Current Clinical Outcomes for IV TPA and Endovascular Stroke Therapies from the INterventional Stroke Therapy Outcomes Registry

Background: There is no national stroke registry that tracks emergency intra-hospital processes of care and 90-day clinical outcomes for both IV TPA and/or emergency endovascular stroke treatment (EVT). We created the INterventional Stroke Therapy Outcomes Registry (INSTOR®) to address this lack of data. Methods: INSTOR is a sophisticated point-and-click analytical tool that tracks emergency processes and clinical outcomes (90-day modified Rankin Scale (mRS) in standard stacked bar chart) for both IV TPA and EVT for acute stroke. Complex analyses are performed in real-time and presented in multiple graphic formats. Single and multivariate risk adjustment for IV TPA and EVT therapies are performed based upon the presence or absence of diabetes, initial stroke severity, age, hypertension, atrial fibrillation, and, for EVT, original location of clot. Results: Since start of use of INSTOR over 30 months ago (data from 10 sites, over 2368 patients, 542 treated ischemic strokes), median times for arrival to CT have declined from 31 to 17 minutes and scan interpretation from 47 to 40 minutes. Arrival to IV TPA has declined from 81 to 70 minutes, and “decision” (TPA-order) to TPA-started from 20 to 13 minutes. Current 90-day mRS 0-1 for IV TPA (minimum NIHSS null, median 11, maximum 36) is 16% for diabetic patients versus 26% for non-diabetic patients. For IV TPA patients, the overall percentage of mRS 0-1 is 22.6 while mRS 0-2 is 44%. However, for those presenting with NIHSS 6-9, mRS 0-2 at 90-days is 76% while those presenting with NIHSS 10-14, it is 43%. For EVT (minimum NIHSS null, median 17, maximum 38), 90-day mRS 0-2 for IV+EVT is 56% at 90-days vs. 32% for EVT alone and variation is shown based upon original clot location. The rate of symptomatic intracranial hemorrhage is 3.8% for IV TPA alone, 6.6% for IV+EVT, and 8.7% for EVT alone. Conclusions: INSTOR is a unique quality improvement tool that presents instant online graphical and numerical analyses of numerous processes of care and clinical outcomes that can be used to improve care.

Abstract T MP59: Texas Stroke Intervention Pre-Hospital Stroke Severity Scale (aka LEGS score): A Triaging Tool for Interventional Stroke Therapy

Introduction: A pre-hospital stroke severity scale that correlates well with an NIHSS of 10 or greater as well as with large vessel occlusions, but is easier and faster to perform than full NIHSS, would be a very useful triaging tool to emergency medical services (EMS). The LEGS score (Lower extremity strength, Eyes/visual fields, Gaze deviation, Speech difficulty) is a 16-point pre-hospital stroke severity scale that is a shortened NIHSS-5. Hypothesis: We assessed the hypothesis that the LEGS score was a useful pre-hospital stroke severity scoring system to identify large vessel acute ischemic strokes. Methods: The LEGS score (0-16) and NIHSS (0-42) were performed in the emergency department over a 6-month period. We retrospectively reviewed those charts for correlation to an NIHSS of 10 or greater and evidence of large-vessel occlusion on either CT or MR Angiography within 48 hours of last known normal. Results: A total of 181 consecutive ischemic stroke patients were evaluated. LEGS score 4 or greater was a good predictor of an NIHSS of 10 or greater (59/181; positive predictive value 92%; and specificity 95%) and false positives noted was 5/181. LEGS score of less than 4 was a good predictor of an NIHSS of less than 10 (108/181; negative predictive value 91%; and sensitivity 95%) and false negatives noted was 10/181. Of those patients 155 underwent intracranial vascular imaging. LEGS score of less than 4 was a good test to rule-out large vessel occlusion (negative predictive value of 86%; 89/103), but had modest sensitivity (69%; 31/45) and positive predictive value (60%; 31/52). The LEGS score of 4 or greater, however, was fairly specific for determining large-vessel occlusions at 81% (89/110). Conclusions: LEGS score of 4 or greater has good correlation with an NIHSS of 10 or greater as well as modest correlation with large vessel occlusion on CT or MR Angiography. This shortened NIHSS-5 may be a useful pre-hospital indicator of patients who may benefit from endovascular intervention.

Interventional Stroke Therapy

Interventional treatment of acute ischemic stroke is currently a “very hot topic,” because acute stroke is a leading cause of disability and one of the most common causes of death worldwide. Ischemic stroke represents 80% to 85% of all strokes. Acute occlusion of cerebral arteries is the most frequent cause of ischemic stroke. Stroke mortality varies between 10% and 17% during the first month, and only about 30% of ischemic stroke patients are independent after 3 mo. Early re-canalization of the occluded brain artery is associated with a significantly higher chance of independence after 90 d and with a significant reduction in mortality. In the last decade, the number of methods used to accelerate artery re-canalization has increased greatly.

Neurothrombectomy for the Treatment of Acute Ischemic Stroke: Results from the TREVO Study

Background: Fast recanalization has been shown to be one of the most important factors for good clinical outcome in stroke patients with acute large vessel occlusion. While intravenous thrombolysis has been shown to be of limited effect in patients with large clot burden, intra-arterial neurothrombectomy offers a new and promising possibility to achieve high recanalization rates within a short time. The Trevo device is a stent-like retriever and was primarily designed to remove thrombus in patients experiencing an acute ischemic stroke. We report on the results of the TREVO Study, which was a prospective, multicenter study in acute stroke patients treated with the Trevo device. Methods: Patients were recruited in seven European centers under the control of an external monitor. Centers were selected because of their long experience with interventional stroke therapy especially with neurothrombectomy. We included adults aged 18-85 years with angiographically confirmed large vessel occlusion strokes and NIHSS scores of 8-30 and treatable within 8 h of symptom onset. The primary endpoint was revascularization, defined as at least TICI (thrombolysis in cerebral infarction) 2a. The revascularization scores were assessed by an independent core lab. Secondary endpoints were clinical outcome at 90 days (mRS 90), any device-related serious adverse events and the rate of symptomatic intracerebral hemorrhages. Results: 60 patients were enrolled. The overall recanalization rate (≥TICI 2a) was 91.7% and TICI 2b and 3 was achieved in 78.3%. At 90 days, 55% of the patients had a favorable neurological outcome (mRS 0-2) and 20% had died. Patients with successful recanalization (TICI 2a,b/3) had a good 90-day neurological outcome (mRS 0-2) in 60%, whereas no patient without recanalization had a mRS 90 <3. The overall rate of symptomatic intracerebral hemorrhage according to the SITS-MOST criteria was 5% (3/60). Conclusions: The study suggest that the Trevo Stentriever™ is a safe and effective device, which may offer the possibility of a high reperfusion rate and a high rate of patients with good clinical outcome after acute ischemic stroke due to proximal arterial occlusion. Randomized trials comparing intravenous thrombolysis with neurothrombectomy are now urgently needed to evaluate this new approach of interventional stroke therapy.

Adapting the Computed Tomography Criteria of Hemorrhagic Transformation to Stroke Magnetic Resonance Imaging

Background: The main safety aspect in the use of stroke thrombolysis and in clinical trials of new pharmaceutical or interventional stroke therapies is the incidence of hemorrhagic transformation (HT) after treatment. The computed tomography (CT)-based classification of the European Cooperative Acute Stroke Study (ECASS) distinguishes four categories of HTs. An HT can range from a harmless spot of blood accumulation to a symptomatic space-occupying parenchymal bleeding associated with a massive deterioration of symptoms and clinical prognosis. In magnetic resonance imaging (MRI) HTs are often categorized using the ECASS criteria although this classification has not been validated in MRI. We developed MRI-specific criteria for the categorization of HT and sought to assess its diagnostic reliability in a retrospective study. Methods: Consecutive acute ischemic stroke patients, who had received a 3-tesla MRI before and 12-36 h after thrombolysis, were screened retrospectively for an HT of any kind in post-treatment MRI. Intravenous tissue plasminogen activator was given to all patients within 4.5 h. HT categorization was based on a simultaneous read of 3 different MRI sequences (fluid-attenuated inversion recovery, diffusion-weighted imaging and T2* gradient-recalled echo). Categorization of HT in MRI accounted for the various aspects of the imaging pattern as the shape of the bleeding area and signal intensity on each sequence. All data sets were independently categorized in a blinded fashion by 3 expert and 3 resident observers. Interobserver reliability of this classification was determined for all observers together and for each group separately by calculating Kendall's coefficient of concordance (W). Results: Of the 186 patients screened, 39 patients (21%) had an HT in post-treatment MRI and were included for the categorization of HT by experts and residents. The overall agreement of HT categorization according to the modified classification was substantial for all observers (W = 0.79). The degrees of agreement between experts (W = 0.81) and between residents (W = 0.87) were almost perfect. For the distinction between parenchymal hematoma and hemorrhagic infarction, the interobserver agreement was almost perfect for all observers taken together (W = 0.82) as well as when experts (W = 0.82) and residents (W = 0.91) were analyzed separately. Conclusion: The ECASS CT classification of HT was successfully adapted for usage in MRI. It leads to a substantial to almost perfect interobserver agreement and can be used for safety assessment in clinical trials.

Abstract 241: Design and Clinical Outcomes of INSTOR (Interventional Stroke Therapy Outcomes Registry)

Background: In the United States there has been no national stroke registry that tracks emergency intra-hospital processes of care and 90-day clinical outcomes for both IV tPA and/or emergency endovascular (IA) stroke treatment. The Joint Commission and other regulatory agencies now mandate use of a national stroke registry based upon concurring recommendations from the Brain Attack Coalition, the American Stroke Association, and the international Multisociety Quality Improvement Guidelines. (online JVIR, Jan 29, 2013) Methods and Results: A custom software development company was employed to create a dedicated on-line national registry for tracking hospital processes and performance trends, and that could perform instant complex multifactorial analyses of clinical outcomes (90-day modified Rankin Score (mRS) based upon numerous patient-specific characteristics. Extensive physician interaction with the software company over a period of years allowed construction of a complex analytical machine with a built-in logic chain for numerous clinical process steps resulting in automatic error detection of out-of-range or impossible answers. The simple self-prompting point and click data entry system typically requires 10 minutes for each stroke alert, 20 minutes for each IV tPA case, and 45 minutes for all aspects of an IA stroke case. INSTOR is a HIPAA compliant, point-and-click national registry that tracks processes-of-care as well as clinical outcomes for both IV tPA and endovascular therapies. All major data points are presented as “site” vs. “All”, with “All” being an anonymous aggregate of data from all participating sites. Conclusions: INSTOR presents instant online graphical and numerical results including “door to CT”, “door to IV tPA”, “time for return of laboratory results” and “time to angiography”, etc. Process trends are presented with graphed monthly median data points overlain by a logistic regression trend line. The computerized multisite database also has the capability of automatically sending text massage or email reminders to designated recipients for follow-up events such as discharge information or 90-day mRS. INSTOR instantly performs complex multifactorial analyses of numerous measures of clinical outcomes for both IV tPA and endovascular stroke interventions and presents this data in standard stacked bar chart form. Outcomes data results include: all ASA Metrics for ischemic stroke, 90-day mRS for IV tPA, IV + IA, and IA treatment alone, and all data points mandated by the international Multisociety Quality Improvement Guidelines. 90-day clinical Outcomes are also analyzed based upon baseline clinical factors such as original NIHSS, vascular occlusion site, and comorbidities such as atrial fibrillation, diabetes, hypertension, and age.

Revascularization grading in endovascular acute ischemic stroke therapy

Recanalization and angiographic reperfusion are key elements to successful endovascular and interventional acute ischemic stroke (AIS) therapy. Intravenous recombinant tissue plasminogen activator (rt-PA), the only established revascularization therapy approved by the US Food & Drug Administration for AIS, may be less effective for large artery occlusion. Thus, there is enthusiasm for endovascular revascularization therapies, which likely provide higher recanalization rates, and trials are ongoing to determine clinical efficacy and compare various methods. It is anticipated that clinical efficacy will be well correlated with revascularization of viable tissue in a timely manner. Reporting, interpretation, and comparison of the various revascularization grading methods require agreement on measurement criteria, reproducibility, ease of use, and correlation with clinical outcome. These parameters were reviewed by performing a Medline literature search from 1965 to 2011. This review critically evaluates current revascularization grading systems. The most commonly used revascularization grading methods in AIS interventional therapy trials are the thrombolysis in cerebral ischemia (TICI, pronounced "tissy") and thrombolysis in myocardial ischemia (TIMI) scores. Until further technical and imaging advances can incorporate real-time reliable perfusion studies in the angio-suite to delineate regional perfusion more accurately, the TICI grading system is the best defined and most widely used scheme. Other grading systems may be used for research and correlation purposes. A new scale that combines primary site occlusion, lesion location, and perfusion should be explored in the future.

E-028 The INterventional Stroke Therapy Outcomes Registry (INSTOR)

PurposeThe INterventional Stroke Therapy Outcomes Registry (INSTOR) was commissioned over a decade ago at the request of the Society of NeuroInterventional Surgery and the American Academy of Neurology Interventional Stroke...

Interventional Stroke Therapies in the Elderly: Are We Helping?

It is unclear whether endovascular therapies for the treatment of AIS are being offered or are safe in older adults. The use and safety of endovascular interventions in patients older than 75 years of age were assessed. A retrospective review of patients with AIS 75 years or older (n = 37/1064) was compared with a younger cohort (n = 70/1190) by using an established data base. Admission and discharge NIHSS scores, rates of endovascular treatment, SICH, in-hospital mortality, and the mBI were assessed. Rates of endovascular treatments were significantly lower in older patients (5.9% in the younger-than-75-year versus 3.5% in the older-than-75-year cohort, P = .007). Stroke severity as measured by the NIHSS score was equivalent in the 2 age groups. The mBI at 12 months was worse in the older patients (mild or no disability in 52% of the younger-than-75-year and 22% in the 75-year-or-older cohort, P = .006). Older patients had higher rates of SICH (9% in younger-than-75-year versus 24% in the 75-year-or-older group, P = .04) and in-hospital mortality (26% in younger-than-75-year versus 46% in the 75-year-or-older group, P = .05). Patients older than 75 years of age were less likely to receive endovascular treatments. Older patients had higher rates of SICH, disability, and mortality. Prospective randomized trials are needed to determine the criteria for selecting patients most likely to benefit from acute endovascular therapies.

Acute Stroke Management: Endovascular Options for Treatment

The management of acute ischemic stroke has advanced greatly over the past 2 decades. New interventions, including intravenous and endovascular treatment strategies, have evolved to recanalize arteries and salvage the ischemic brain. The evolution of interventional approaches to the treatment of acute stroke has been prompted by the limitations of intravenous therapy and intended to extend the treatment window, improve recanalization rates, and subsequently long-term clinical outcomes. The major techniques that have defined the current field of interventional acute stroke management and the relevant past and current data, and ongoing clinical trials on interventional stroke therapy will be reviewed. New issues, such as futile recanalization, and time to microcatheter, will also be discussed.

P-009 Trend towards using mechanical thrombectomy devices in stroke interventions in recent years

PurposeMechanical thrombectomy is a promising new modality of interventional stroke treatment. The use of these devices has been steadily increasing over the past 2–3 years.In recent years, multiple trials have...