Machine learning, deep learning and hernia surgery. Are we pushing the limits of abdominal core health? A qualitative systematic review

INTRODUCTION

This systematic review aims to evaluate the use of machine learning and artificial intelligence in hernia surgery.

METHODS

The PRISMA guidelines were followed throughout this systematic review. The ROBINS-I and Rob 2 tools were used to perform qualitative assessment of all studies included in this review. Recommendations were then summarized for the following pre-defined key items: protocol, research question, search strategy, study eligibility, data extraction, study design, risk of bias, publication bias, and statistical analysis.

RESULTS

A total of 13 articles were ultimately included for this review, describing the use of machine learning and deep learning for hernia surgery. All studies were published from 2020 to 2023. Articles varied regarding the population studied, type of machine learning or Deep Learning Model (DLM) used, and hernia type. Of the thirteen included studies, all included either inguinal, ventral, or incisional hernias. Four studies evaluated recognition of surgical steps during inguinal hernia repair videos. Two studies predicted outcomes using image-based DMLs. Seven studies developed and validated deep learning algorithms to predict outcomes and identify factors associated with postoperative complications.

CONCLUSION

The use of ML for abdominal wall reconstruction has been shown to be a promising tool for predicting outcomes and identifying factors that could lead to postoperative complications.

Association between CT Perfusion Parameters and Hemorrhagic Transformation after Endovascular Treatment in Acute Ischemic Stroke: Results from the ESCAPE-NA1 Trial

BACKGROUND AND PURPOSE

Hemorrhagic transformation can occur as a complication of endovascular treatment for acute ischemic stroke. This study aimed to determine whether ischemia depth as measured by admission CTP metrics can predict the development of hemorrhagic transformation at 24 hours.

MATERIALS AND METHODS

Patients with baseline CTP and 24-hour follow-up imaging from the ESCAPE-NA1 trial were included. RAPID software was used to generate CTP volume maps for relative CBF, CBV, and time-to-maximum at different thresholds. Hemorrhage on 24-hour imaging was classified according to the Heidelberg system, and volumes were calculated. Univariable and multivariable regression analyses assessed the association between CTP lesion volumes and hemorrhage/hemorrhage subtypes.

RESULTS

Among 408 patients with baseline CTP, 142 (35%) had hemorrhagic transformation at 24-hour follow-up, with 89 (63%) classified as hemorrhagic infarction (HI1/HI2), and 53 (37%), as parenchymal hematoma (PH1/PH2). Patients with HI or PH had larger volumes of low relative CBF and CBV at each threshold compared with those without hemorrhage. After we adjustied for baseline and treatment variables, only increased relative CBF <30% lesion volume was associated with any hemorrhage (adjusted OR, 1.14; 95% CI, 1.02-1.27 per 10 mL), as well as parenchymal hematoma (adjusted OR, 1.23; 95% CI, 1.06-1.43 per 10 mL). No significant associations were observed for hemorrhagic infarction.

CONCLUSIONS

Larger "core" volumes of relative CBF <30% were associated with an increased risk of PH following endovascular treatment. This particular metric, in conjunction with other clinical and imaging variables, may, therefore, help estimate the risk of post-endovascular treatment hemorrhagic complications.

Sex differences in acute stroke metrics and outcome dependent on COVID status

BACKGROUND AND PURPOSE

Biological sex is known to have an impact on quality metrics of acute stroke. We aimed to determine whether COVID positivity accentuates this effect and constitutes worse outcome.

METHODS

The present analysis was based on the Global COVID-19 Stroke Registry, a retrospective, international, cohort study of consecutive ischemic stroke patients receiving intravenous thrombolysis and/or endovascular thrombectomy between 1 March 2020 and 30 June 2021. We investigated differences between the sexes in patient characteristics, acute stroke metrics as well as post-stroke outcome in COVID-positive and COVID-negative stroke patients undergoing acute revascularization procedures.

RESULTS

A total of 15,128 patients from 106 centers were recorded in the Global COVID-19 Stroke Registry, 853 (5.6%) of whom were COVID-positive. Overall, COVID-positive individuals were treated significantly slower according to every acute stroke metric compared to COVID-negative patients. We were able to show that key quality indicators in acute stroke treatment were unfavorable for COVID-negative women compared to men (last-seen-well-to-door time + 11 min in women). Furthermore, COVID-negative women had worse 3-month outcomes (3-month modified Rankin Scale score [interquartile range] 3.0 [4.0] vs. 2.0 [3.0]; p < 0.01), even after adjusting for confounders. In COVID-positive individuals no such difference between the sexes, either in acute management metrics or in 3-month outcome, was seen.

CONCLUSION

Known sex-related differences in acute stroke management exist and extend to times of crisis. Nevertheless, if patients were COVID-19-positive at stroke onset, women and men were treated the same, which could be attributed to structured treatment pathways.

Influence of Infarct Morphology and Patterns on Cognitive Outcomes After Endovascular Thrombectomy

BACKGROUND

To assess the association of qualitative and quantitative infarct characteristics and 3 cognitive outcome tests, namely the Montreal Cognitive Assessment (MOCA) for mild cognitive impairment, the Boston Naming Test for visual confrontation naming, and the Sunnybrook Neglect Assessment Procedure for neglect, in large vessel occlusion stroke.

METHODS

Secondary observational cohort study using data from the randomized-controlled ESCAPE-NA1 trial (Safety and Efficacy of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke), in which patients with large vessel occlusion undergoing endovascular treatment were randomized to receive either intravenous Nerinetide or placebo. MOCA, Sunnybrook Neglect Assessment Procedure, and 15-item Boston Naming Test were obtained at 90 days. Total infarct volume, gray matter, and white matter infarct volumes were manually measured on 24-hour follow-up imaging. Infarcts were also visually classified as either involving the gray matter only or both the gray and white matter and scattered versus territorial. Associations of infarct variables and cognitive outcomes were analyzed using multivariable ordinal or binary logistic regression models.

RESULTS

Of 1105 patients enrolled in ESCAPE-NA1, 1026 patients with visible infarcts on 24-hour follow-up imaging were included. MOCA and Sunnybrook Neglect Assessment Procedure were available for 706 (68.8%) patients and the 15-item Boston Naming Test was available for 682 (66.5%) patients. Total infarct volume was associated with worse MOCA scores (adjusted common odds ratio per 10 mL increase, 1.05 [95% CI, 1.04-1.06]). After adjusting for baseline variables and total infarct volume, mixed gray and white matter involvement (versus gray matter-only adjusted common odds ratio, 1.92 [95% CI, 1.37-2.69]), white matter infarct volume (adjusted common odds ratio per 10 mL increase 1.36 [95% CI, 1.18-1.58]) and territorial (versus scattered) infarct pattern (adjusted common odds ratio, 1.65 [95% CI, 1.15-2.38]) were associated with worse MOCA scores. Results for Sunnybrook Neglect Assessment Procedure and 15-item Boston Naming Test were similar, except for the territorial infarct pattern, which did not reach statistical significance in multivariable analysis.

CONCLUSIONS

Besides total infarct volume, infarcts that involve the white matter and that show a territorial distribution were associated with worse cognitive outcomes, even after adjusting for total infarct volume.

Outcomes after Perioperative Transient Ischemic Attack Following Cardiac Surgery

Perioperative transient ischemic attacks (PTIAs) are associated with significantly increased rates of postoperative complications such as low cardiac output, atrial fibrillation, and significantly higher mortality in cardiac procedures. The current literature on PTIAs is sparse and understudied. Therefore, we aim to understand the effects of PTIA on hospital utilization, readmission, and morbidity. Using data on all the cardiac procedures at the University of Pittsburgh Medical Center from 2011 to 2019, fine and gray analysis was performed to identify whether PTIAs and covariables correlate with increased hospital utilization, stroke, all-cause readmission, Major Adverse Cardiac and Cerebrovascular Events (MACCE), MI, and all-cause mortality. Logistic regression for longer hospitalization showed that PTIA (HR: 2.199 [95% CI: 1.416-3.416] increased utilization rates. Fine and gray modeling indicated that PTIA (HR: 1.444 [95% CI: 1.096-1.902], p < 0.01) increased the rates of follow-up all-cause readmission. However, PTIA (HR: 1.643 [95% CI: 0.913-2.956] was not statistically significant for stroke readmission modeling. Multivariate modeling for MACCE events within 30 days of surgery (HR: 0.524 [95% CI: 0.171-1.605], p > 0.25) and anytime during the follow-up period (HR: 1.116 [95% CI: 0.825-1.509], p > 0.45) showed no significant correlation with PTIA. As a result of PTIA's significant burden on the healthcare system due to increased utilization, it is critical to better define and recognize PTIA for timely management to improve perioperative outcomes.

CT Perfusion Does Not Modify the Effect of Reperfusion in Patients with Acute Ischemic Stroke Undergoing Endovascular Treatment in the ESCAPE-NA1 Trial

BACKGROUND AND PURPOSE

Although reperfusion is associated with improved outcomes in patients with acute ischemic stroke undergoing endovascular treatment, many patients still do poorly. We investigated whether CTP modifies the effect of near-complete reperfusion on clinical outcomes, ie, whether poor clinical outcomes despite near-complete reperfusion can be partly or fully explained by CTP findings.

MATERIALS AND METHODS

Data are from the Safety and Efficacy of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke (ESCAPE-NA1) trial. Admission CTP was processed using RAPID software, generating relative CBF and CBV volume maps at standard thresholds. CTP lesion volumes were compared in patients with-versus-without near-complete reperfusion. Associations between each CTP metric and clinical outcome (90-day mRS) were tested using multivariable logistic regression, adjusted for baseline imaging and clinical variables. Treatment-effect modification was assessed by introducing CTP lesion volume × reperfusion interaction terms in the models.

RESULTS

CTP lesion volumes and reperfusion status were available in 410/1105 patients. CTP lesion volumes were overall larger in patients without near-complete reperfusion, albeit not always statistically significant. Increased CBF <34%, CBV <34%, CBV <38%, and CBV <42% lesion volumes were associated with worse clinical outcome (ordinal mRS) at 90 days. CTP core lesion volumes did not modify the treatment effect of near-complete recanalization on clinical outcome.

CONCLUSIONS

CTP did not modify the effect of near-complete reperfusion on clinical outcomes. Thus, CTP cannot explain why some patients with near-complete reperfusion have poor clinical outcomes.

Mediation of Successful Reperfusion Effect through Infarct Growth and Cerebral Edema: A Pooled, Patient-Level Analysis of EXTEND-IA Trials and SELECT Prospective Cohort

OBJECTIVE

Reperfusion therapy is highly beneficial for ischemic stroke. Reduction in both infarct growth and edema are plausible mediators of clinical benefit with reperfusion. We aimed to quantify these mediators and their interrelationship.

METHODS

In a pooled, patient-level analysis of the EXTEND-IA trials and SELECT study, we used a mediation analysis framework to quantify infarct growth and cerebral edema (midline shift) mediation effect on successful reperfusion (modified Treatment in Cerebral Ischemia ≥ 2b) association with functional outcome (modified Rankin Scale distribution). Furthermore, we evaluated an additional pathway to the original hypothesis, where infarct growth mediated successful reperfusion effect on midline shift.

RESULTS

A total 542 of 665 (81.5%) eligible patients achieved successful reperfusion. Baseline clinical and imaging characteristics were largely similar between those achieving successful versus unsuccessful reperfusion. Median infarct growth was 12.3ml (interquartile range [IQR] = 1.8-48.4), and median midline shift was 0mm (IQR = 0-2.2). Of 249 (37%) demonstrating a midline shift of ≥1mm, median shift was 2.75mm (IQR = 1.89-4.21). Successful reperfusion was associated with reductions in both predefined mediators, infarct growth (β = -1.19, 95% confidence interval [CI] = -1.51 to -0.88, p < 0.001) and midline shift (adjusted odds ratio = 0.36, 95% CI = 0.23-0.57, p < 0.001). Successful reperfusion association with improved functional outcome (adjusted common odds ratio [acOR] = 2.68, 95% CI = 1.86-3.88, p < 0.001) became insignificant (acOR = 1.39, 95% CI = 0.95-2.04, p = 0.094) when infarct growth and midline shift were added to the regression model. Infarct growth and midline shift explained 45% and 34% of successful reperfusion effect, respectively. Analysis considering an alternative hypothesis demonstrated consistent results.

INTERPRETATION

In this mediation analysis from a pooled, patient-level cohort, a significant proportion (~80%) of successful reperfusion effect on functional outcome was mediated through reduction in infarct growth and cerebral edema. Further studies are required to confirm our findings, detect additional mediators to explain successful reperfusion residual effect, and identify novel therapeutic targets to further enhance reperfusion benefits. ANN NEUROL 2023.

RESCUE BT 2, a multicenter, randomized, double-blind, double-dummy trial of intravenous tirofiban in acute ischemic stroke: study rationale and design

BACKGROUND

Tirofiban is a glycoprotein IIb/IIIa receptor inhibitor that has been shown to be effective in the treatment of acute coronary syndromes. However, it remains unknown whether it improves outcomes in patients with acute ischemic stroke.

OBJECTIVE

This trial investigates the efficacy and safety of tirofiban compared with aspirin for acute ischemic stroke within 24 hours after symptom onset.

METHODS AND DESIGN

The Efficacy and Safety of Tirofiban Compared with Aspirin in the Treatment of Acute Ischemic Stroke (RESCUE BT 2) Trial is an investigator-initiated, prospective, randomized, double-blind, double-dummy, multicenter clinical trial. Up to 1158 eligible patients will be consecutively randomized to receive antiplatelet therapy with tirofiban or aspirin in 1:1 ratio across approximately 100 stroke centers in China.

OUTCOMES

The primary endpoint is the proportion of patients with excellent functional outcome defined as modified Rankin scale score of 0 to 1 at 90 days after randomization. Lead safety endpoints include symptomatic intracerebral hemorrhage at 48 hours and mortality at 90 days. Trial registry number: ChiCTR2000029502 (www.chictr.org.cn).

Interventional compared with medical management of symptomatic carotid web: A systematic review

BACKGROUND

Carotid web (CaW) is non-atheromatous, shelf-like intraluminal projection, generally affecting the posterolateral wall of the proximal internal carotid artery, and associated with embolic stroke, particularly in younger patients without traditional stroke risk factors. Treatment options for symptomatic CaWs include interventional therapy with carotid endarterectomy or carotid stenting versus medical therapy with antiplatelet or anticoagulants. As safety and efficacy of these approaches have been incompletely delineated in small-to-moderate case series, we performed a systematic review of outcomes with interventional and medical management.

METHODS

Systematic literature search was conducted and data analyzed per PRISMA guidelines (Preferred Reporting Items for Systemic Reviews and Meta-Analyses) from January 2000 to October 2021 using the search strategy: "Carotid web" OR "Carotid shelf" OR "Web vessels" OR "Intraluminal web". Patient-level demographics, stroke risk factors, technical procedure details, medical and interventional management strategies were abstracted across 15 series. All data were analyzed using descriptive statistics.

RESULTS

Among a total of symptomatic 282 CaW patients across 14 series, age was 49.5 (44-55.7) years, 61.7% were women, and 76.6% were black. Traditional stroke risk factors were less frequent than the other stroke causes, including hypertension in 28.6%, hyperlipidemia 14.6%, DM 7.0%, and smoking 19.8%. Thrombus adherent to CaW was detected on initial imaging in 16.2%. Among 289 symptomatic CaWs across 15 series, interventional management was pursued in 151 (52.2%), carotid artery stenting in 87, and carotid endarterectomy in 64; medical management was pursued in 138 (47.8%), including antiplatelet therapy in 80.4% and anticoagulants in 11.6%. Interventional and medical patients were similar in baseline characteristics. The reported time from index stroke to carotid revascularization was median 14 days (IQR 9.5-44). In the interventional group, no periprocedural mortality was noted, major periprocedural complications occurred in 1/151 (0.5%), and no recurrent ischemic events were observed over follow-up range of 3-60 months. In the medical group, over a follow-up of 2-55 months, the recurrence cerebral ischemia rate was 26.8%.

CONCLUSION

Cumulative evidence from multiple series suggests that carotid revascularization is a safe and effective option for preventing recurrent ischemic events in patients with symptomatic carotid webs.

Clinical Results of the Advanced Neurovascular Access Catheter System Combined With a Stent Retriever in Acute Ischemic Stroke (SOLONDA)

BACKGROUND

The Advanced Neurovascular Access (ANA) thrombectomy system is a novel stroke thrombectomy device comprising a self-expanding funnel designed to reduce clot fragmentation by locally restricting flow while becoming as wide as the lodging artery. Once deployed, the ANA device allows distal aspiration combined with a stent retriever to mobilize the clot into the funnel where it remains copped during extraction. We investigated the safety and efficacy of ANA catheter system.

METHODS

SOLONDA (Solitaire in Combination With the ANA Catheter System as Manufactured by Anaconda) was a prospective, open, single-arm, multicenter trial with blinded assessment of the primary outcome by an independent core lab. Patients with anterior circulation vessel occlusion admitted within 8 hours from symptom onset were eligible. The primary end point was successful reperfusion (modified Thrombolysis in Cerebral Infarction score 2b-3) with ≤3 passes of the ANA device in combination with stent retriever, before the use of rescue therapy in the intention to treat population. Primary predefined analysis was noninferiority as compared to the performance end point observed in HERMES (High Effective Reperfusion Using Multiple Endovascular Devices).

RESULTS

After enrollment of 74 patients, an interim analysis was conducted, and the trial Steering Committee decided to terminate recruitment due to safety and performance objectives were reached. Mean age was 71.6 (SD 8.9) years, 46.6% women and median National Institutes of Health Stroke Scale on admission 14 (interquartile range, 10-19). Successful reperfusion within 3 passes before rescue therapy was achieved in 60/72 (83.3% [95% CI, 74.7%-91.9%]) with a rate of complete reperfusion (modified Thrombolysis in Cerebral Infarction score 2c-3) of 60% (95% CI, 48.4%-71.1%; 43/72 patients). After noninferiority was confirmed (P<0.01), the ANA device also showed superiority in the rate of successful reperfusion with ≤3 passes (P=0.02). First-pass successful recanalization rate was 55.6% (95% CI, 44.1%-67.0%), with a first-pass complete recanalization rate of 38.9% (95% CI, 27.6%-50.1%). Rescue therapy to obtain a modified Thrombolysis in Cerebral Infarction score 2b-3 was needed in 12/72 (17%) patients. At 90 days, the rate of favorable functional outcome (modified Rankin Scale score 0-2) was 57.5% (95% CI, 46.2%-68.9%), and the rate of excellent functional outcome (modified Rankin Scale score 0-1) was 45.2% (95% CI, 33.8%-56.6%). The rate of severe adverse device related was 1.4%.

CONCLUSIONS

In this clinical experience, the ANA device achieved a high rate of complete recanalization with a preliminary good safety profile and favorable 90 days clinical outcomes.

Endovascular treatment for acute Basilar Artery Occlusion - a multicenter randomized controlled trial (ATTENTION)

BACKGROUND AND HYPOTHESIS

Recently, two multicenter randomized controlled trials (RCT) failed to show a significantly beneficial effect of endovascular treatment (EVT) in patients with acute basilar artery occlusion (BAO). However, both trials suffered from equipoise issues which may have hindered the validity of the trial results. Therefore, additional RCT studies are needed to explore the potential benefit of EVT in patients presenting with BAO.

STUDY DESIGN

ATTENTION is an investigator-initiated, multicenter, prospective, randomized, controlled clinical trial with open-label treatment and blinded outcome assessment (PROBE) of EVT versus best medical management (BMM). The primary effect parameter is a modified Rankin Score of 0-3 at day 90.

DISCUSSION

ATTENTION will provide evidence for the efficacy and safety of EVT in stroke patients within 12 hours after BAO.

Prestroke Disability and Outcome After Thrombectomy for Emergent Anterior Circulation Large Vessel Occlusion Stroke

BACKGROUND AND OBJECTIVES

To determine the impact of endovascular therapy for large vessel occlusion stroke in patients with vs those without premorbid disability.

METHODS

We performed a post hoc analysis of the TREVO Stent-Retriever Acute Stroke (TRACK) Registry, which collected data on 634 consecutive patients with stroke treated with the Trevo device as first-line endovascular thrombectomy (EVT) at 23 centers in the United States. We included patients with internal carotid or middle cerebral (M1/M2 segment) artery occlusions, and the study exposure was patient- or caregiver-reported premorbid modified Rank Scale (mRS) score ≥2 (premorbid disability [PD]) vs premorbid mRS score of 0 to 1 (no PD [NPD]). The primary outcome was no accumulated disability, defined as no increase in 90-day mRS score from the patient's premorbid mRS score.

RESULTS

Of the 634 patients in TRACK, 407 patients were included in our cohort, of whom 53 (13.0%) had PD. The primary outcome of no accumulated disability was achieved in 37.7% (20 of 53) of patients with PD and 16.7% (59 of 354) of patients with NPD (p < 0.001), while death occurred in 39.6% (21 of 53) and 14.1% (50 of 354) (p < 0.001), respectively. The adjusted odds ratio of no accumulated disability for patients with PD was 5.2 (95% confidence interval [CI] 2.4-11.4, p < 0.001) compared to patients with NPD. However, the adjusted odds ratio for death in patients with PD was 2.90 (95% CI 1.38-6.09, p = 0.005).

DISCUSSION

In this study of patients with anterior circulation acute ischemic stroke treated with EVT, we found that PD was associated with a higher probability of not accumulating further disability compared to patients with NPD but also with higher probability of death.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that in anterior circulation acute ischemic stroke treated with EVT, patients with PD compared to those without disability were more likely not to accumulate more disability but were more likely to die.

Strength of Association between Infarct Volume and Clinical Outcome Depends on the Magnitude of Infarct Size: Results from the ESCAPE-NA1 Trial

BACKGROUND AND PURPOSE

Infarct volume is an important predictor of clinical outcome in acute stroke. We hypothesized that the association of infarct volume and clinical outcome changes with the magnitude of infarct size.

MATERIALS AND METHODS

Data were derived from the Safety and Efficacy of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke (ESCAPE-NA1) trial, in which patients with acute stroke with large-vessel occlusion were randomized to endovascular treatment plus either nerinetide or a placebo. Infarct volume was manually segmented on 24-hour noncontrast CT or DWI. The relationship between infarct volume and good outcome, defined as mRS 0-2 at 90 days, was plotted. Patients were categorized on the basis of visual grouping at the curve shoulders of the infarct volume/outcome plot. The relationship between infarct volume and adjusted probability of good outcome was fitted with linear or polynomial functions as appropriate in each group.

RESULTS

We included 1099 individuals in the study. Median infarct volume at 24 hours was 24.9 mL (interquartile range [IQR] = 6.6-92.2 mL). On the basis of the infarct volume/outcome plot, 4 infarct volume groups were defined (IQR = 0-15 mL, 15.1-70 mL, 70.1-200 mL, >200 mL). Proportions of good outcome in the 4 groups were 359/431 (83.3%), 219/337 (65.0%), 71/201 (35.3%), and 16/130 (12.3%), respectively. In small infarcts (IQR = 0-15 mL), no relationship with outcome was appreciated. In patients with intermediate infarct volume (IQR = 15-200 mL), there was progressive importance of volume as an outcome predictor. In infarcts of > 200 mL, outcomes were overall poor.

CONCLUSIONS

The relationship between infarct volume and clinical outcome varies nonlinearly with the magnitude of infarct size. Infarct volume was linearly associated with decreased chances of achieving good outcome in patients with moderate-to-large infarcts, but not in those with small infarcts. In very large infarcts, a near-deterministic association with poor outcome was seen.

Abstract P524: Impact of Intra-Procedural Workflow and Time Metrics of Establishing Fast Reperfusion on Clinical Outcomes in the ESCAPE-NA1 Trial

Background: Time from imaging to establishing reperfusion is a major influencer of clinical outcomes and over the years thrombectomy techniques have evolved rapidly. This has led to improvements in achieving fast and complete reperfusion. We analyzed the impact of various intra-procedural techniques and tools on the speed of reperfusion and correlated procedural duration with probability of achieving good clinical outcomes.

Methods: We analyzed intra-procedural time metrics and examined factors leading to delays during EVT. The relationship between outcome (mRS Scale) and procedural time from arterial puncture to time of achieving mTICI 2b-3 First Reperfusion (FRE) was modeled using logistic regression.

Results: The various procedural time metrics are summarized in Figure 1. Every 10-minute increase in FRE time reduced the probability of achieving functional independence(90-day modified Rankin Scale 0-2) by 6.7% (P=0.021, adjusted). The medianFRE timewas 25min (IQR 17-39) and was significantly longer in patients with tandem occlusions(median 34min, p 0.0005). General anesthesia vs procedural sedation vs no sedation use did not significantly alter the FRE time (p = 0.1453). The use of BGC (54.2%) was nominally longer FRE (median 26min “IQR 18-38” vs 23ming, “IQR 16-38”; p 0.095)while the use of contact aspiration (n=213) vs retrievable stents (n=676) as the first approach was associated with a shorter FRE time (21min “IQR 14-35” vs 26 min “IQR18-40”, p =0.001).

Conclusions: Puncture to first reperfusion time is a significant predictor of clinical outcome in theESCAPE-NA1 trial. Various procedural and anatomical factors influence this timemetric.

Figure: Intra-Procedural workflow time metrics expressed in medians and 90th percentiles. The cumulative times are calculated for each major milestone in the procedure for upto three attempts. First reperfusion duration where TICI 2b was achieved is shown in comparison to other procedural time metrics.

Abstract P536: Impact of the Covid-19 Pandemic on the Volumes and Outcomes of Acute Ischemic Stroke and Myocardial Infarction

Introduction: The COVID-19 pandemic has wreaked havoc on the presentation, care and outcomes of patients with acute cerebrovascular and cardiovascular conditions. We sought to measure the national impact of COVID-19 on the care for acute ischemic stroke (AIS) and acute myocardial infarction (AMI).

Methods: In this retrospective, observational study, we used the Premier Healthcare Database to evaluate the changes in the volume of care and hospital outcomes for AIS and AMI in relation to the pandemic. The pandemic months were defined from March 1, 2020- April 30, 2020 and compared to the same period in the year prior. Outcome measures were volumes of hospitalization and reperfusion treatment for AIS and AMI (including intravenous thrombolysis [IVT] and/or mechanical thrombectomy [MT] for AIS and percutaneous coronary interventions [PCI] for AMI) as well as in-hospital mortality, hospital length of stay (LOS) and hospitalization costs were compared across a 2-month period at the height of the pandemic versus the corresponding period in the prior year.

Results: There were 95,453 AIS patients across 145 hospitals and 19,744 AMI patients across 126 hospitals. There was a significant nation-wide decline in the absolute number of hospitalizations for AIS (-38.94%;95%CI,-34.75% to -40.71%) and AMI (-38.90%;95%CI,-37.03% to -40.81%) as well as IVT (-30.32%;95%CI,-27.02% to -33.83%), MT (-23.54%;95%CI,-19.84% to -27.70%), and PCI (-35.05%;95%CI,-33.04% to -37.12%) during the first two months of the pandemic. This occurred across low-, mid-, and high-volume centers and in all geographic regions. Higher in-hospital mortality was observed in AIS patients (5.7% vs.4.2%, p=0.0037;OR 1.41,95%CI 1.1-1.8) but not

AMI patients. A shift towards an increase in the proportion of admitted AIS and AMI patients receiving reperfusion therapies suggests a greater clinical severity among patients that were hospitalized for these conditions during the pandemic. A shorter length of stay (AIS: -17%, AMI: -20%), and decreased hospitalization costs (AIS: -12%, AMI: -19%) were observed.

Conclusions: Our findings shed light on the combined health outcomes and economic impact the COVID-19 pandemic has had on acute stroke and cardiac emergency care.

Abstract P467: Clinical Effectiveness of Endovascular Stroke Treatment in the Early and Extended Time Windows

Background and Purpose: The clinical efficacy of mechanical thrombectomy (MT) has been unequivocally demonstrated in multiple randomized clinical trials (RCTs). However, these studies were performed in carefully selected centers and utilized strict inclusion criteria. We aim to assess the clinical effectiveness of MT by comparing the specific RCT populations with corresponding patient cohorts derived from a prospective registry.

Methods: A total of 2008 patients from 76 sites across 12 countries were enrolled in a prospective open-label MT registry. Patients were categorized into the corresponding cohorts of the SWIFT-Prime, DAWN, and DEFUSE 3 trials based on the age, baseline NIHSS, occlusion site, IV tPA use, pre-morbid mRS and time to treatment criteria used in the RCTs without considering specific parenchymal imaging findings. Baseline and outcome variables were compared across the corresponding groups.

Results: As compared to the treated patients in the actual trials, registry-derived patients tended to be younger and had lower baseline ASPECTS. In addition, time to treatment was earlier and the use of IV tPA and general anesthesia were higher in DAWN- and DEFUSE 3-registry derived patients versus their corresponding trials. Reperfusion rates were higher in the registry patients. The rates of 90-day good outcome (mRS 0-2) in registry-derived patients were comparable to those of the patients treated in the corresponding RCTs (SWIFT-Prime, 64.5% vs 60.2%; DAWN, 50.4% vs 48.6%; Beyond-DAWN: 52.4% vs 48.6%; DEFUSE 3, 52% vs 44.6%, respectively; all P>0.05). Registry-derived patients had significant less disability than the corresponding RCT controls (ordinal mRS shift OR, P <0.05 for all).

Conclusion: Our study provides favorable generalizability data for the safety and efficacy of thrombectomy in the “real-world” setting and supports that patients may be safely treated outside the constraints of RCTs and strict guidelines.

Abstract P496: Clot Characteristics in Mechanical Thrombectomy: Interim Analysis of the EXCELLENT Registry

Introduction: Red blood cell (RBC) rich vs fibrin rich clots have different mechanical properties and greater knowledge about clot composition in the context of clinical, imaging, and procedural factors in mechanical thrombectomy (MT) may help with procedural optimization. The EXCELLENT Registry (NCT03685578) is a prospective, global, multi-center, observational registry of EmboTrap as the first line MT device for large vessel occlusion (LVO). We present an interim analysis of clot collected per pass in the registry.

Methods: Five hundred thirty-three clot specimens from 376 subjects were collected by 20 sites and sent for analysis by independent Central Labs under standardized protocol. Analysis was interrupted by COVID-19, but the labs were fully operational as of June 2020 and on track to deliver results for 300 subjects in Q4. At the time of abstract submission, composition data for 234 clots from 163 subjects was available. All available data will be presented at the time of the conference.

Results: Cardioembolic etiology (n=100) was associated with lower RBC (40.2 vs 47.2%) and higher fibrin content (31.7 vs 26.7%) compared to large artery disease (n=12). Hyperdense/vessel susceptibility sign (78+, 24-, per independent imaging core lab) corresponded to higher mean RBC content (44.4 vs 34.9%). Treatment with IV tPA (60+, 91-) had no clear impact on clot composition (42.3 vs 40.6% RBC; 30.4 vs 30.0% fibrin). Notably, clots retrieved with the first 2 passes of were more RBC rich (42.1 vs 28.0%) and clots retrieved in higher passes had a higher average fibrin content (35.5 vs 29.6%) suggesting that higher fibrin content leads to greater refractoriness.

Conclusions: Clot density/susceptibility on baseline imaging, stroke etiology and number of thrombectomy passes were associated with differential clot composition. These findings may have potential implications for the development of better MT strategies.

Abstract 42: Epidemiological Surveillance of the Impact of the Covid-19 Pandemic on Stroke Care Using Artificial Intelligence

Background: The degree to which the COVID-19 pandemic has affected systems of care, in particular those for time-sensitive conditions such as stroke, remains poorly quantified. We sought to evaluate the impact of COVID-19 in the overall screening for acute stroke utilizing a commercial clinical artificial intelligence (AI) platform.

Methods: Data were derived from the Viz Platform, an AI application designed to optimize the workflow of acute stroke patients. Neuroimaging data on suspected stroke patients across 97 hospitals in 20 US states were collected in real-time and retrospectively analyzed with the number of patients undergoing imaging screening serving as a surrogate for the amount of stroke care. The main outcome measures were the number of CTA, CTP, Large vessel occlusions (LVOs) (defined according to the automated software detection), and severe strokes on CTP (defined as those with hypoperfusion volumes>70mL) normalized as number of patients per day per hospital. Data from the pre-pandemic (November 4, 2019 to February 29, 2020) and pandemic (March 1 to May 10, 2020) periods were compared at national and state levels. Correlations were made between the inter-period changes in imaging screening, stroke hospitalizations, and thrombectomy procedures using state-specific sampling.

Results: A total of 23,223 patients were included. The incidence of LVO on CTA and severe strokes on CTP were 11.2%(n=2,602) and 14.7%(n=1,229/8,328), respectively. There were significant declines in the overall number of CTAs (-22.8%;1.39 to 1.07 patients/day/hospital,p<0.001) and CTPs (-26.1%;0.50 to 0.37 patients/day/hospital,p<0.001) as well as in the incidence of LVO (-17.1%;0.15 to 0.13 patients/day/hospital,p<0.001) and severe strokes on CTP (-16.7%;0.12 to 0.10 patients/day/hospital, p<0.005). The sampled cohort showed similar declines in the rates of LVOs versus thrombectomy (18.8%vs.19.5%, p=0.9) and CSC hospitalizations (18.8%vs.11.0%, p=0.4).

Conclusions: A significant decline in stroke imaging screening has occurred during the COVID-19 pandemic. This underscores the broader application of AI neuroimaging platforms for the real-time monitoring of stroke systems of care.

Abstract 45: Global Impact of the Covid-19 Pandemic on Stroke Hospitalizations and Mechanical Thrombectomy Volumes: A Society of Vascular and Interventional Neurology Covid-19 International Collaboration

Introduction: The COVID-19 pandemic led to profound changes in both the organization of health care systems and the psychosocial behavior of the population worldwide. The extent to which the COVID-19 outbreak disrupted stroke systems of care merits study from a global lens.

Methods: We conducted a retrospective, observational, international study, across 6 continents, 40 countries, and 187 comprehensive stroke centers. The study objectives were to measure the global impact of the pandemic on the volumes for mechanical thrombectomy (MT), stroke and intracranial hemorrhage (ICH) hospitalizations over a 3-month period at the height of the pandemic (March 1 to May 31, 2020) compared with two control 3-month periods prior (immediately preceding and one year prior). A secondary objective was to examine whether these changes in volume were impacted by COVID-19 and baseline hospital center stroke volumes. Third, we evaluated the relationships between stroke and COVID-19 diagnoses.

Results: There were 26,699 stroke admissions in the 3 months immediately before compared to 21,576 admissions during the pandemic months, representing a 19.2% (95%CI,-19.7 to -18.7) decline. There were 5,191 MT procedures in the 3 months preceding compared to 4,533 procedures during the pandemic, representing a 12.7% (95%CI,-13.6 to -11.8) drop. Significant reductions were also seen in relation to the prior year control period. The decreases were noted across centers with high, intermediate, and low COVID-19 hospitalization burden, and also across high, intermediate, and low volume stroke centers. High-volume COVID-19 centers (-20.5%) had greater declines in MT volumes than mid- (-10.1%) and low-volume (-8.7%) centers. 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.

Conclusions: The COVID-19 pandemic was associated with a global decline in the volume of overall stroke hospitalizations, MT procedures, ischemic stroke/TIA and ICH admission volumes. Despite geographic variations, these volume reductions were observed regardless of COVID-19 hospitalization burden and pre-pandemic stroke and MT volumes. Centers with higher COVID-19 inpatient volumes experienced steeper declines.

Clinical outcomes of isolated deep grey matter infarcts after endovascular treatment of large vessel occlusion stroke

PURPOSE

There are few data on the prevalence and impact of isolated deep grey matter infarction in acute stroke. In this study, we aimed to investigate the prevalence of isolated deep grey matter infarcts and their impact on the outcome.

METHODS

Infarcts on 24-h follow-up imaging (non-contrast head CT or diffusion-weighted MRI) in the ESCAPE-NA1 trial were categorized into predominantly deep grey matter infarcts vs. infarcts involving additional territories ("other infarcts"). Total infarct volume was manually segmented. Baseline characteristics and proportions of good outcome (primary outcome, defined as modified Rankin Score [mRS] 0-2 at 90 days), excellent outcome (mRS 0-1) and mortality were compared between patients with and without predominantly deep grey matter infarcts. Multivariable logistic regression with adjustment for baseline variables and total infarct volume was used to determine a possible association of predominantly deep grey matter infarcts and clinical outcome.

RESULTS

Predominantly deep grey matter infarcts were seen in 316/1026 patients (30.8%). Compared to other patients, their ASPECTS was higher, collateral status and reperfusion quality were better and time to treatment was shorter. Good outcome was seen in 239/316 (75.6%) with vs. 374/704 (53.1%) without predominantly deep grey matter infarcts. After adjusting for baseline variables and total infarct volume, predominantly deep grey matter infarcts were independently associated with excellent outcome (_adjOR: 1.45 [CI₉₅: 1.04-2.02]), but not with good outcome (_adjOR: 1.24 [CI₉₅: 0.86-1.80]) or mortality (_adjOR: 0.73 [CI₉₅:0.39-1.35]) CONCLUSION: Predominantly deep grey matter infarct patterns were seen in 1/3rd of patients and were significantly associated with increased chances of excellent outcome, independent of patient baseline status and infarct size.

Stroke etiologies in patients with COVID-19: the SVIN COVID-19 multinational registry

BACKGROUND AND PURPOSE

Coronavirus disease 2019 (COVID-19) is associated with a small but clinically significant risk of stroke, the cause of which is frequently cryptogenic. In a large multinational cohort of consecutive COVID-19 patients with stroke, we evaluated clinical predictors of cryptogenic stroke, short-term functional outcomes and in-hospital mortality among patients according to stroke etiology.

METHODS

We explored clinical characteristics and short-term outcomes of consecutively evaluated patients 18 years of age or older with acute ischemic stroke (AIS) and laboratory-confirmed COVID-19 from 31 hospitals in 4 countries (3/1/20-6/16/20).

RESULTS

Of the 14.483 laboratory-confirmed patients with COVID-19, 156 (1.1%) were diagnosed with AIS. Sixty-one (39.4%) were female, 84 (67.2%) white, and 88 (61.5%) were between 60 and 79 years of age. The most frequently reported etiology of AIS was cryptogenic (55/129, 42.6%), which was associated with significantly higher white blood cell count, c-reactive protein, and D-dimer levels than non-cryptogenic AIS patients (p

CONCLUSIONS

Our findings suggest that cryptogenic stroke among COVID-19 patients carries a significant risk of early mortality.

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Key Words

• COVID-19
• Coronavirus
• Cryptogenic
• Mortality
• Stroke

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MESH Headings

• Adult
• Aged
• Aged, 80 and over
• Brain Ischemia
• COVID-19/blood
• COVID-19/complications
• COVID-19/diagnostic imaging
• COVID-19/mortality
• Cohort Studies
• Computed Tomography Angiography
• Egypt/epidemiology
• Female
• Fibrin Fibrinogen Degradation Products/metabolism
• Hospital Mortality
• Humans
• Ischemic Stroke/blood
• Ischemic Stroke/diagnostic imaging
• Ischemic Stroke/mortality
• Ischemic Stroke/virology
• Magnetic Resonance Imaging
• Male
• Middle Aged
• Registries
• Retrospective Studies
• Risk Factors
• SARS-CoV-2
• Spain/epidemiology
• Stroke
• United States/epidemiology

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Affiliation(s)

María E Ramos-Araque Institute of Biomedical Research of Salamanca, Department of Neurology, Hospital Universitario de Salamanca, Salamanca, Spain Department of Neurology, Hospital Clínico Universitario de Valladolid, Valladolid, Spain
James E Siegler Cooper Neurologic Institute, Cooper University Hospital, Camden, NJ, USA.
Marc Ribo Stroke Unit, Department of Neurology, Vall d'Hebron Research Institute, Barcelona, Spain Departament of Medicina, Universitat Autónoma de Barcelona, Barcelona, Spain
Manuel Requena Stroke Unit, Department of Neurology, Vall d'Hebron Research Institute, Barcelona, Spain Departament of Medicina, Universitat Autónoma de Barcelona, Barcelona, Spain
Cristina López Department of Neurology, Hospital Clínico Universitario de Valladolid, Valladolid, Spain
Mercedes de Lera Department of Neurology, Hospital Clínico Universitario de Valladolid, Valladolid, Spain
Juan F Arenillas Department of Neurology, Hospital Clínico Universitario de Valladolid, Valladolid, Spain
Isabel Hernández Pérez Department of Neurology, Hospital Clínico Universitario de Valladolid, Valladolid, Spain
Beatriz Gómez-Vicente Department of Neurology, Hospital Clínico Universitario de Valladolid, Valladolid, Spain
Blanca Talavera Department of Neurology, Hospital Clínico Universitario de Valladolid, Valladolid, Spain
Pere Cardona Portela Department of Neurology, Hospital Universitari, Bellvitge, Barcelona, Spain
Ana Nuñez Guillen Department of Neurology, Hospital Universitari, Bellvitge, Barcelona, Spain
Xabier Urra Department of Neurology, Hospital Clínic, Barcelona, Spain
Laura Llull Department of Neurology, Hospital Clínic, Barcelona, Spain
Arturo Renú Department of Neurology, Hospital Clínic, Barcelona, Spain
Thanh N Nguyen Department of Neurology, Department of Radiology, Department of Neurosurgery, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA
Dinesh Jillella Department of Neurology, Emory University School of Medicine, Atlanta, USA
Fadi Nahab Department of Neurology, Emory University School of Medicine, Atlanta, USA
Raul Nogueira Department of Neurology, Grady Memorial Hospital, Atlanta, GA, USA
Diogo Haussen Department of Neurology, Grady Memorial Hospital, Atlanta, GA, USA
Ryna Then Cooper Neurologic Institute, Cooper University Hospital, Camden, NJ, USA
Jesse M Thon Cooper Neurologic Institute, Cooper University Hospital, Camden, NJ, USA
Luis Rodríguez Esparragoza Stroke Unit, Neuroscience Department, Hospital Universitari Germans Trias i Pujol, Badalona, Barcelona, Spain
Maria Hernández-Pérez Stroke Unit, Neuroscience Department, Hospital Universitari Germans Trias i Pujol, Badalona, Barcelona, Spain
Alejandro Bustamante Stroke Unit, Neuroscience Department, Hospital Universitari Germans Trias i Pujol, Badalona, Barcelona, Spain
Ossama Yassin Mansour Neurology Department, Stroke and neurointervention unit, Alexandria University, Alexandria, Egypt
Mohammed Megahed Critical care Department, Alexandria University, Alexandria, Egypt
Tamer Hassan Neurosurgery Department, Stroke and Neurointervention unit, Alexandria University, Alexandria, Egypt
David S Liebeskind Department of Neurology, Ronald Reagan UCLA Medical Center, Los Angeles, USA
Ameer Hassan Department of Clinical Neuroscience Research, Valley Baptist Medical Center, Harlingen, TX, USA Department of Neurology, University of Texas Rio Grande Valley, Harlingen, TX, USA
Saif Bushnaq Neuroscience Institute, Bon Secours Mercy Health St. Vincent Hospital, Toledo, OH, USA
Mohamed Osman Neuroscience Institute, Bon Secours Mercy Health St. Vincent Hospital, Toledo, OH, USA
Alejandro Rodriguez Vazquez Department of Neurology, Hospital Clínic, Barcelona, Spain

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Safety and Outcome of Carotid Dissection Stenting During the Treatment of Tandem Occlusions

Background and Purpose:

The efficacy of endovascular therapy in patients with acute ischemic stroke due to tandem occlusion is comparable to that for isolated intracranial occlusion in the anterior circulation. However, the optimal management of acute cervical internal carotid artery lesions is unknown, especially in the setting of carotid dissection, but emergency carotid artery stenting (CAS) is frequently considered. We investigated the safety and efficacy of emergency CAS for carotid dissection in patients with acute stroke with tandem occlusion in current clinical practice.

Methods:

We retrospectively analyzed a prospectively maintained database composed of 2 merged multicenter international observational real-world registries (Endovascular Treatment in Ischemic Stroke and Thrombectomy in Tandem Lesion). Data from endovascular therapy performed in the treatment of tandem occlusions related to acute cervical carotid dissection between January 2012 and January 2019 at 24 comprehensive stroke centers were analyzed.

Results:

The study assessed 136 patients with tandem occlusion due to dissection, including 65 (47.8%) treated with emergency CAS and 71 (52.2%) without. The overall rates of favorable outcome (90-day modified Rankin Scale score, 0–2) and successful reperfusion (modified Thrombolysis in Cerebral Infarction, 2b–3) were 58.0% (n=76 [95% CI, 49.6%–66.5%]) and 77.9% (n=106 [95% CI, 71.0%–85.0%]), respectively. In subgroup analyses, the rate of successful reperfusion (89.2% versus 67.6%; adjusted odds ratio, 2.24 [95% CI, 1.33–3.77]) was higher after CAS, whereas the 90-day favorable outcome (54.3% versus 61.4%; adjusted odds ratio, 0.84 [95% CI, 0.58–1.22]), symptomatic intracerebral hemorrhage (sICH; 10.8% versus 5.6%; adjusted odds ratio, 1.59 [95% CI, 0.79–3.17]), and 90-day mortality (8.0% versus 5.8%; adjusted odds ratio, 1.00 [95% CI, 0.48–2.09]) did not differ. In sensitivity analyses of patients with successful intracranial reperfusion, CAS was not associated with an improved clinical outcome.

Conclusions:

Emergency stenting of the dissected cervical carotid artery during endovascular therapy for tandem occlusions seems safe, whatever the quality of the intracranial reperfusion.

Considerations for Antiplatelet Management of Carotid Stenting in the Setting of Mechanical Thrombectomy: A Delphi Consensus Statement

BACKGROUND AND PURPOSE

There are only few data and lack of consensus regarding antiplatelet management for carotid stent placement in the setting of endovascular stroke treatment. We aimed to develop a consensus-based algorithm for antiplatelet management in acute ischemic stroke patients undergoing endovascular treatment and simultaneous emergent carotid stent placement.

MATERIALS AND METHODS

We performed a literature search and a modified Delphi approach used Web-based questionnaires that were sent in several iterations to an international multidisciplinary panel of 19 neurointerventionalists from 7 countries. The first round included open-ended questions and formed the basis for subsequent rounds, in which closed-ended questions were used. Participants continuously received feedback on the results from previous rounds. Consensus was defined as agreement of ≥70% for binary questions and agreement of ≥50% for questions with >2 answer options. The results of the Delphi process were then summarized in a draft manuscript that was circulated among the panel members for feedback.

RESULTS

A total of 5 Delphi rounds were performed. Panel members preferred a single intravenous aspirin bolus or, in jurisdictions in which intravenous aspirin is not available, a glycoprotein IIb/IIIa receptor inhibitor as intraprocedural antiplatelet regimen and a combination therapy of oral aspirin and a P2Y12 inhibitor in the postprocedural period. There was no consensus on the role of platelet function testing in the postprocedural period.

CONCLUSIONS

More and better data on antiplatelet management for carotid stent placement in the setting of endovascular treatment are urgently needed. Panel members preferred intravenous aspirin or, alternatively, a glycoprotein IIb/IIIa receptor inhibitor as an intraprocedural antiplatelet agent, followed by a dual oral regimen of aspirin and a P2Y12 inhibitor in the postprocedural period.

Antiplatelet Management for Stent-Assisted Coiling and Flow Diversion of Ruptured Intracranial Aneurysms: A DELPHI Consensus Statement

BACKGROUND AND PURPOSE

There is a paucity of data regarding antiplatelet management strategies in the setting of stent-assisted coiling/flow diversion for ruptured intracranial aneurysms. This study aimed to identify current challenges in antiplatelet management during stent-assisted coiling/flow diversion for ruptured intracranial aneurysms and to outline possible antiplatelet management strategies.

MATERIALS AND METHODS

The modified DELPHI approach with an on-line questionnaire was sent in several iterations to an international, multidisciplinary panel of 15 neurointerventionalists. The first round consisted of open-ended questions, followed by closed-ended questions in the subsequent rounds. Responses were analyzed in an anonymous fashion and summarized in the final manuscript draft. The statement received endorsement from the World Federation of Interventional and Therapeutic Neuroradiology, the Japanese Society for Neuroendovascular Therapy, and the Chinese Neurosurgical Society.

RESULTS

Data were collected from December 9, 2019, to March 13, 2020. Panel members achieved consensus that platelet function testing may not be necessary and that antiplatelet management for stent-assisted coiling and flow diversion of ruptured intracranial aneurysms can follow the same principles. Preprocedural placement of a ventricular drain was thought to be beneficial in cases with a high risk of hydrocephalus. A periprocedural dual, intravenous, antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor was preferred as a standard approach. The panel agreed that intravenous medication can be converted to oral aspirin and an oral P2Y12 inhibitor within 24 hours after the procedure.

CONCLUSIONS

More and better data on antiplatelet management of patients with ruptured intracranial aneurysms undergoing stent-assisted coiling or flow diversion are urgently needed. Panel members in this DELPHI consensus study preferred a periprocedural dual-antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor.

COVID-19 and neurointerventional service worldwide: a survey of the European Society of Minimally Invasive Neurological Therapy (ESMINT), the Society of NeuroInterventional Surgery (SNIS), the Sociedad Iberolatinoamericana de Neuroradiologia Diagnostica y Terapeutica (SILAN), the Society of Vascular and Interventional Neurology (SVIN), and the World Federation of Interventional and Therapeutic Neuroradiology (WFITN)

BACKGROUND

This survey was focused on the provision of neurointerventional services, the current practices of managing patients under COVID-19 conditions, and the expectations for the future.

METHODS

Invitations for this survey were sent out as a collaborative effort of the European Society of Minimally Invasive Neurological Therapy (ESMINT), the Society of NeuroInterventional Surgery (SNIS), the Sociedad Iberolatinoamericana de Neuroradiologia Diagnostica y Terapeutica (SILAN), the Society of Vascular and Interventional Neurology (SVIN), and the World Federation of Interventional and Therapeutic Neuroradiology (WFITN).

RESULTS

Overall, 475 participants from 61 countries responded (six from Africa (1%), 81 from Asia (17%), 156 from Europe (33%), 53 from Latin America (11%), and 172 from North America (11%)). The majority of participants (96%) reported being able to provide emergency services, though 26% of these reported limited resources. A decrease in emergency procedures was reported by 69% of participants (52% in ischemic and hemorrhagic stroke, 11% ischemic, and 6% hemorrhagic stroke alone). Only 4% reported an increase in emergency cases. The emerging need for social distancing and the rapid adoption of remote communication was reflected in the interest in establishing case discussion forums (43%), general online forums (37%), and access to angio video streaming for live mentoring and support (33%).

CONCLUSION

Neurointerventional emergency services are available in almost all centers, while the number of emergency patients is markedly decreased. Half of the participants have abandoned neurointerventions in non-emergent situations. There are considerable variations in the management of neurointerventions and in the expectations for the future.

INFOMATAS multi-center systematic review and meta-analysis individual patient data of dynamic cerebral autoregulation in ischemic stroke

Rationale

Disturbances in dynamic cerebral autoregulation after ischemic stroke may have important implications for prognosis. Recent meta-analyses have been hampered by heterogeneity and small samples.

Aim and/or hypothesis

The aim of study is to undertake an individual patient data meta-analysis (IPD-MA) of dynamic cerebral autoregulation changes post-ischemic stroke and to determine a predictive model for outcome in ischemic stroke using information combined from dynamic cerebral autoregulation, clinical history, and neuroimaging.

Sample size estimates

To detect a change of 2% between categories in modified Rankin scale requires a sample size of ∼1500 patients with moderate to severe stroke, and a change of 1 in autoregulation index requires a sample size of 45 healthy individuals (powered at 80%, α = 0.05). Pooled estimates of mean and standard deviation derived from this study will be used to inform sample size calculations for adequately powered future dynamic cerebral autoregulation studies in ischemic stroke.

Methods and design

This is an IPD-MA as part of an international, multi-center collaboration (INFOMATAS) with three phases. Firstly, univariate analyses will be constructed for primary (modified Rankin scale) and secondary outcomes, with key co-variates and dynamic cerebral autoregulation parameters. Participants clustering from within studies will be accounted for with random effects. Secondly, dynamic cerebral autoregulation variables will be validated for diagnostic and prognostic accuracy in ischemic stroke using summary receiver operating characteristic curve analysis. Finally, the prognostic accuracy will be determined for four different models combining clinical history, neuroimaging, and dynamic cerebral autoregulation parameters.

Study outcome(s)

The outcomes for this study are to determine the relationship between clinical outcome, dynamic cerebral autoregulation changes, and baseline patient demographics, to determine the diagnostic and prognostic accuracy of dynamic cerebral autoregulation parameters, and to develop a prognostic model using dynamic cerebral autoregulation in ischemic stroke.

Discussion

This is the first international collaboration to use IPD-MA to determine prognostic models of dynamic cerebral autoregulation for patients with ischemic stroke.

Abstract TP18: First-Pass Effect May Reduce the Impact of Delays to Treatment in Endovascular Thrombectomy: Analysis of the STRATIS Registry

Introduction: First-pass reperfusion effect (FPE) appears superior to multiple device passes in achieving good functional recovery in endovascular thrombectomy (EVT). It is unclear if this represents an epiphenomenon or a true independent effect. Historically, earlier treatment has been associated with improved functional recovery. We analyzed how these two variables interact using the STRATIS registry data.

Methods: The STRATIS registry prospectively enrolled large vessel occlusion, stroke patients, treated with Solitaire and/or Mindframe Capture low profile revascularization devices within 8 hours of symptom onset. Reperfusion was assessed by an independent core lab.

Results: A total of 984 patients were enrolled (mean age 67.8 +/- 14.7 years, 54.2% male, median NIHSS 17). Mean time from stroke onset to groin puncture was 226.4+/- 100.0 minutes. At 90 days, functional recovery (mRS 0-2) was achieved in 56.5%. Core lab assessment was performed in 824 cases with a mTICI2b/3 rate of 87.9%. Every 60-minute delay to treatment was associated with less functional recovery cOR 0.79 (95% CI, 0.68 - 0.93). In patients with first-pass effect reperfusion (FPE), delay to treatment did not affect functional recovery FPE-mTICI 2b cOR 1.03 (95% CI, 0.83 - 1.28) or FPE-mTICI 2c/3 cOR 0.96 (95% CI, 0.84 - 1.11). Poor reperfusion (FPE-mTICI <2b) maintained a negative relationship between functional recovery and delay to treatment cOR 0.76 (95% CI, 0.66 - 0.88).

Conclusion: First pass effect may reduce the impact of delays to treatment compared to historical data. Further studies to determine the mechanism of this effect are required.

Abstract WMP10: The Role of Intravenous Thrombolysis Before Mechanical Thrombectomy: A Subgroup Analysis of the RESILIENT Trial

Background: Mechanical thrombectomy (MT) in addition to intravenous thrombolysis (IVT) is now the recommended treatment for acute ischemic stroke (AIS) patients with large vessel occlusion (LVO). The positive trials also demonstrated that MT alone among patients ineligible for IVT is an effective therapy for AIS. Whether MT alone is as effective, worse, or better than pretreatment with IVT before MT among IVT-eligible AIS patients with LVO is debatable. We aimed to assess the effect of IVT on the clinical outcome of MT in the RESILIENT trial.

Methods: RESILIENT was a randomized, prospective, multicenter, controlled trial evaluating the safety, efficacy, and cost-effectiveness of thrombectomy versus medical treatment alone. A total of 221 patient were enrolled. The trial showed a strong benefit to thrombectomy (90-day mRS ordinal shift, OR 95%CI). All eligible patients received intravenous tPA within the 4.5-hour-window. The primary end-point was the common odds ratio (cOR) of mRs at 90 days (shift analysis) and the main secondary endpoint was the rate of functional independence (mRS 0-2) at 90 days. Ordinal logistic and binary regression analyses with the use of intravenous tPA as an interaction term were performed with adjustments for potential confounders including age, baseline NIHSS score, occlusion site, IV tPA use and ASPECTS. A p value < 0.05 was considered statistically significant.

Results: Among 221 randomized patients (median NIHSS, 18 IQR [14-21]), 155 (70%) were treated with IV tPA. The frequency of good recanalization (TICI 2b> ) and of hemorrhagic transformation was not affected by IVT. There was no significant difference in the treatment effect size across patients who received intravenous tPA versus those who did not in terms of overall functional disability (ordinal mRS shift: aOR: 2.63, 95%CI [1.48-4.69] vs. 1.54, 95%CI [0.63-3.74]; p=0.42) or functional independence (mRS 0-2: aOR: 3.06, 95%CI [1.37-6.48] vs. 1.71 95%CI [0.55-5.33], p=0.40) at 90 days.

Conclusions: The large effect size of MT on LVO outcomes was not significantly affected by IVT. Further studies directly evaluating the role of IVT before MT are of utmost importance.

Abstract 141: Artificial Intelligence to Improve the Detection and Triage of Cerebral Aneurysms

Cerebral Aneurysms (CAs) may occur in 5-10% of the population. They can be often missed because they require a very methodological diagnostic approach. We developed an algorithm using artificial intelligence to assist and supervise and detect CAs.

Methods: We developed an automated algorithm to detect CAs. The algorithm is based on 3D convolutional neural network modeled as a U-net. We included all saccular CAs from 2014 to 2016 from a single center. Normal and pathological datasets were prepared and annotated in 3D using an in-house developed platform. To assess the accuracy and to optimize the model, we assessed preliminary results using a validation dataset. After the algorithm was trained, a dataset was used to evaluate final IA detection and aneurysm measurements. The accuracy of the algorithm was derived using ROC curves and Pearson correlation tests.

Results: We used 528 CTAs with 674 aneurysms at the following locations: ACA (3%), ACA/ACOM (26.1%), ICA/MCA (26.3%), MCA (29.4%), PCA/PCOM (2.3%), Basilar (6.6%), Vertebral (2.3%) and other (3.7%). Training datasets consisted of 189 CA scans. We plotted ROC curves and achieved an AUC of 0.85 for unruptured and 0.88 for ruptured CAs. We improved the model performance by increasing the training dataset employing various methods of data augmentation to leverage the data to its fullest. The final model tested was performed in 528 CTAs using 5-fold cross-validation and an additional set of 2400 normal CTAs. There was a significant improvement compared to the initial assessment, with an AUC of 0.93 for unruptured and 0.94 for ruptured. The algorithm detected larger aneurysms more accurately, reaching an AUC of 0.97 and a 91.5% specificity at 90% sensitivity for aneurysms larger than 7mm. Also, the algorithm accurately detected CAs in the following locations: basilar(AUC of 0.97) and MCA/ACOM (AUC of 0.94). The volume measurement (mm3) by the model compared to the annotated one achieved a Pearson correlation of 99.36.

Conclusion: The Viz.ai aneurysm algorithm was able to detect and measure ruptured and unruptured CAs in consecutive CTAs. The model has demonstrated that a deep learning AI algorithm can achieve clinically useful levels of accuracy for clinical decision support.

Abstract 149: Successful Reperfusion After Endovascular Treatment Predicted Favorable Outcome in the Basilar Artery Occlusion Endovascular Intervention versus Standard Medical Treatment (BEST) Trial

Background: Several randomized trials have demonstrated a strong benefit of endovascular reperfusion in the anterior circulation strokes. The association between successful reperfusion and outcomes is less well established in acute vertebrobasilar artery occlusions (VBAO). We aim to investigate the association between successful reperfusion and 90-day favorable outcome in BEST trial.

Methods: The BEST trial was a multicenter randomized controlled trial of endovascular treatment versus medical treatment alone in VBAO. In the current analysis, we included patients who underwent endovascular treatment in the As-Treated Population of our trial. Successful reperfusion was defined as modified Thrombolysis in Cerebral Infarction Score (mTICI) 2b/3 post-intervention. Favorable outcome was defined as mRS 0-3. Logistic regression was used to investigate the association between successful reperfusion and outcome.

Results: The trial was terminated prematurely in September-2017 after enrolling 131 patients due to a high cross-over rate (Control to the ET=14; ET to Control=3). A total of 77 patients received endovascular treatment were included in this analysis. Baseline characteristics and outcome measures according to Intention-To-Treat (IIT), Per-Protocol (PP), and As-Treated (AT) analyses are summarized in Table 1 . Successful reperfusion was achieved in 70.1% (54/77) patients. Multivariable logistic regression adjusted for age and baseline NIHSS score showed that successful reperfusion was significantly associated with favorable outcome at 90 days (adjusted OR, 3.16; 95% CI, 1.05 to 9.48, p=0.04) as well as a strong trend towards lower 90-day mortality (adjusted OR, 0.36; 95% CI, 0.12 to 1.06, p=0.06).

Conclusion: Endovascular reperfusion was associated with better 90-day functional outcome and a trend towards lower mortality in the BEST Trial.

Table 1: Baseline Characteristics and Outcomes Measures:

Abstract WP52: Defining and Predicting Fast Progression of Infarct Growth in Large Vessel Occlusion Strokes

Background and Purpose: Identification of patients with failing collaterals and rapid progression of infarct growth (fast progressors) is crucial when assessing patients for potential transfer from primary to comprehensive stroke centers endovascular therapy (ET).

Methods: Review of a prospectively collected database of endovascular patients with anterior circulation Large vessel occlusion strokes from 09/2010-11/2018. Patients with adequate CTP maps and follow-up final infarct volume (FIV) measurements who achieved full reperfusion (mTICI 2c-3) were included.Infarct growth rate was calculated as the difference between FIV and the acute CTP core volume, divided by time from CTP to reperfusion in hours. Receiver operating characteristic analysis was used to identify the optimal infarct growth rate that better discriminated 90-day good outcome(mRS 0-2). Fast progression was defined as having an infarct growth rate above the identified threshold.

Results: 461 patients qualified for the study. The optimal infarct growth rate threshold to predict good outcome was 3.9 ml/h (sensitivity 79%, specificity 47%). 286 (62%) were subsequently categorized as fast progressors. There were no differences in baseline characteristics between fast and slow progressors except for higher NIHSS(16[12-21]vs16[11-21],p=0.02), longer Last known normal to CT times (367 mins [219-679]vs 269.5[111.5-570],p<0.001) and smaller CTP core volumes (3.8cc[0-20] vs 8[0-25.5],p=0.02). Fast progressors had larger FIV (36.7[18.6-66.9] vs 7[3.5-16],p<0.001), lower rates of good outcome (52.8% vs 77.4%, p<0.001), higher mortality rates (17.5% vs 6%,p=0.02). There was a trend toward higher rates of parenchymal hematomas in fast progressors (5.1% vs 1.7%,p=0.07). On multivariate analysis, only ASPECTS was an independent predictor of fast progression (aOR 0.7 95%CI[0.54-0.91,p=0.007) while CTP parameters did not reach statistical significance.

Conclusions: Fast progression of infarct growth is associated with poorer clinical outcomes. ASPECTS may help triage transfers when assessing patients for ET. Larger studies are warranted.

Abstract TP54: Visual Aids for Patient, Family, and Physician Decision Making About Late Imaging-Guided Endovascular Thrombectomy for Acute Ischemic Stroke

Background: Speedy decision-making is helpful for optimal outcomes from endovascular thrombectomy (EVT) for acute ischemic stroke (AIS). Visual displays may facilitate rapid review of relevant outcomes with different courses of action, but have not yet been developed for late-presenting patients selected for EVT based on multimodal CT or MR imaging.

Methods: From pooled, study-level randomized trial (DAWN and DEFUSE 3) data, 100 person-icon arrays (Kuiper-Marshall personographs) were generated showing beneficial and adverse effects of endovascular thrombectomy for patients with acute cerebral ischemia and large vessel occlusion using (1) automated (algorithmic) and (2) expert-guided joint outcome table specification.

Results: Among imaging-selected patients 6-24 hours from last known well, for the full 7-category modified Rankin Scale (mRS), endovascular thrombectomy had number needed to treat to benefit 1.9 (IQR 1.9-2.1) and number needed to harm 40.0 (29.2-58.3). Visual displays of treatment effects among 100 patients showed that, with EVT: 52 patients have better disability outcome, including 32 more achieving functional independence (mRS 0-2); 3 patients have worse disability outcome, including 1 more experiencing severe disability or death (mRS 5-6), mediated by symptomatic intracranial hemorrhage and infarct in new territory. The person-icon figure integrated these outcomes, and early side-effects, in a single display (Figure). Similar features were present in person-icon figures based on a 6-level mRS (levels 5 and 6 combined) rather than 7-level mRS, and giving special emphasis to normal or near-normal outcome (mRS 0-1) rather than functional independence (mR 0-2).

Conclusion: Personograph visual decision aids are now available to rapidly educate patients, family, and healthcare providers on the benefits and risks of late, imaging-guided endovascular thrombectomy therapies for acute ischemic stroke.

Abstract WP50: Cost-Effectiveness of Mechanical Thrombectomy for Acute Ischemic Stroke: An Analysis From RESILIENT Trial

Background and purpose: RESILIENT Trial was the first study in a developing country to demonstrate the benefit of mechanical thrombectomy (MT) in acute stroke patients. This economic evaluation aimed to access the cost-utility of MT under the perspective of the Brazilian Public Healthcare System.

Methods: Analysis was based on a subset sample of the original study (151 of 221 patients) from 4 hospitals. We compared costs and utilities between MT plus standard care (n=78) vs. standard care alone (n=73). Direct medical costs were considered, and utilities were inputted according to each patient’s Utility-Weighted modified Rankin Score (UW-mRS). First-year survival was obtained from trial follow-up and modelled for a life-time horizon adjusted by National Mortality Data. Direct medical costs were converted to I$ using Purchasing Power Parity (PPP). A discount rate of 5% was used. Incremental cost-effectiveness ratio (ICER) is expressed in cost (I$) per Quality-Adjusted Life Year (QALY).

Results: RESILIENT trial was stopped on its first interim analysis because of early efficacy. The incremental costs and QALYs gained with MT were estimated at I$ 8,369 and 0.75, respectively, compared with standard medical care, yielding an incremental cost-effectiveness ratio (ICER) of I$ 7,256 per QALY.

Conclusion: The initially higher costs of MT were offset by the clear benefit of the intervention. RESILIENT trial demonstrated that such therapy is likely to be cost-effective despite the economical constraints in the Brazilian healthcare system.

Abstract WMP6: Stenting Placement During Endovascular Treatment in VBAO Was Not Associated With 90-Day Outcome in the Basilar Artery Occlusion Endovascular Intervention versus Standard Medical Treatment (BEST) Trial

Background: The impact of intracranial stenting placement during endovascular treatment for acute vertebrobasilar artery occlusion (VBAO) remains elusive. We aim to investigate the influence of intracranial stenting on 90-day outcomes in the BEST trial.

Methods: All patients who underwent endovascular treatment in BEST trial were included in the analysis. The primary efficacy and safety outcome measures were the 90-day rate of favorable outcome (mRS 0-3) and mortality, respectively. Logistic regression was used to investigate the association between stenting placement and outcome.

Results: All 77 patients who received endovascular treatment in the trial were included (e.g. full As-Treated population). Baseline and procedural characteristics are summarized in Table 1 . Stenting was performed in 26% (20/77) of the patients. Favorable outcome was achieved in 46.8% patients and mortality rate was 29.9%. Multivariable logistic regression showed that stenting placement in VBAO was not a predictor of either 90-day favorable outcome (adjusted OR, 0.91; 95% CI, 0.31 to 2.65, p=0.86) or 90-day mortality (adjusted OR, 0.91; 95% CI, 0.28 to 3.00, p=0.88).

Conclusion: Stenting placement in VBAO during endovascular treatment did not impact outcomes in the BEST trial. Our data suggest that stent placement is a reasonable option for selected VBAO patients.

Table 1: Baseline Characteristics and Outcomes Measures in as-treated population.

Abstract WP9: Impact of Sex Differences on the Treatment Effect of Mechanical Thrombectomy: A Subgroup Analysis of the RESILIENT Trial

Background: Despite evidence supporting the overall efficacy of mechanical thrombectomy (MT) in acute ischemic stroke (AIS) due to large vessel occlusion (LVO) of the anterior circulation, it is unclear whether the treatment effect of MT differs by sex in different populations. We assessed the impact of sex differences in the treatment effect of MT in the RESILIENT trial.

Methods: RESILIENT was a prospective, multicenter, randomized phase III trial that was designed to assess the safety, efficacy, and cost-effectiveness of mechanical thrombectomy as compared to medical treatment alone in patients treated under the less than ideal conditions typically found in the public healthcare system of a developing country.

Results: Among 221 patients enrolled in the trial, 104 (47,1%) were female. Baseline characteristics were well balanced between sexes, except for a higher prevalence of hypertension (76% vs. 57.4%; p=0.004) and diabetes (34.3% vs. 21.7%; p=0.039) and a lower frequency of alcohol abuse (4% vs. 28.9%; p=0.001) in females. After adjustment for baseline characteristics, we found a significant interaction (p=0.026) between sex and the effect of MT with a lower efficacy of MT for functional independency at 90 days among women (aOR=1.13;95%CI:0.42-3.02) compared to men (aOR=4.78; 95%CI:1.88-12.15).

Conclusions: In our study population of patients with AIS caused by LVO of the anterior circulation, women were less likely to benefit from MT than men. Further studies are necessary to investigate these findings.

Abstract 98: Direct Transfer to Angio-suite to Reduce Times to Intra-arterial Treatment and Improve Outcomes in Large Vessel Occlusion Strokes: A Multicenter Matched Analysis

Background and Purpose: Bypassing the emergency department (ED) and the CT suite by directly transporting to the neuroangiography suite for imaging assessment and treatment may shorten reperfusion times while maintaining proper patient selection.

Methods: Patients from prospectively collected databases of 4 international comprehensive stroke centers with large vessel occlusion strokes transferred for endovascular therapy (ET) were identified and divided into 2 groups:(1) Direct to angio-suite (DTAS) and (2) standard protocol including CT+/-CTA/CTP. Only patient with anterior circulation strokes, pre-mRS 0-2 and baseline NIHSS The groups were matched for age and baseline NIHSS ≥6 were included. Baseline characteristics, time metrics and outcomes were compared.

Results: 548 patients (274 pairs) were included in the analysis. Baseline characteristics were well-balanced. DTAS patients had shorter median picture-to-puncture (14 [8-20] vs 37 [25-50] minutes, p<0.001)and door-to-reperfusion (68 [57-91.5] vs 100.5 [74-140] minutes,p<0.001)times. In terms of outcomes, DTAS patients had higher rates of successful reperfusion (mTICI 2b-3, 87.2% vs 73.3%, p<0.001) and full reperfusion (mTICI 2c-3, 51.3% vs 38.3%, p=0.004), and lower rates of parenchymal hematomas (14% vs 27%, p<0.001). There were no differences between groups in rates of good outcome (90-day mRS-0-2, 39.2% vs 38.5%, p=0.87) and 90-day mortality (24.2% vs 24.9%, p=0.87).

Conclusions: DTAS is safe, feasible and an effective strategy to reduce treatment times. The clinical benefit of this approach should be assessed in a prospective randomized trial.

Abstract WP61: Artificial Intelligence for Automated Detection of Large Vessel Occlusion Strokes

Introduction: Identification of Large Vessel Occlusion (LVO) in acute ischemic stroke (AIS) patients is critical for proper decision-making. Limited availability of trained experts and delays in LVO recognition can have a detrimental effect on outcomes. We sought to evaluate an artificial intelligence-based algorithm for LVO detection in AIS.

Methods: A retrospective analysis of a prospectively-collected database of AIS patients admitted to a large volume stroke center between 2014-2018 was performed. Experienced vascular neurologists graded CTA for presence and site of LVO. Concurrently, studies were analyzed by the Viz-LVO Algorithm® version 1.4 (GA) - a convolutional neural network programmed to detect occlusions from the internal carotid artery terminus (ICA-T) to the sylvian fissure, which would include all MCA M1-segment and most M2-segment lesions. CTA readings were categorized as LVOs (ICA-T, MCA-M1, MCA-M2) versus non-LVOs/more distal occlusions. Comparisons between human and AI-based readings were done by accuracy analysis and calculating Cohen’s kappa.

Results: A total of 610 CTAs were analyzed. The AI algorithm rejected 3.4% of the CTAs due to poor quality. Viz-LVO identified LVOs with an overall sensitivity of 81.3%, specificity of 87.8%, and accuracy of 83.2% (AUC 0.845 (95%CI:0.81-0.88, p<0.001). Table 1 shows the results per occlusion site. Accuracy was higher for ICA-T and M1 occlusions as compared to M2 occlusions. The mean run time of the algorithm was 2.78±0.5minutes.

Conclusion: Our study demonstrates that automated AI reading allows for fast and accurate identification of LVO strokes. Future efforts should be made to improve the detection of the more distal occlusions.

Abstract WP75: Comparison of Automated CT Perfusion Software for Prediction of Final Infarct Volume

Introduction: CT Perfusion (CTP) has been increasingly used in patient selection for acute reperfusion therapies. Perfusion software allow for automated and faster processing using standardized approaches. We aim to compare the perfusion parameters and final infarct volume (FIV) predictability of two commercially available CTP packages (RAPID and Viz.ai).

Methods: Retrospective analysis of a mechanical thrombectomy database of mechanical thrombectomy between 9/ 2018- 6/ 2019. Patients without a technically adequate baseline CTP were excluded. Ischemic core was defined as CBF<30%. Patients with (1) complete post-treatment reperfusion (mTICI 2c-3) and (2) absence of parenchymal hematoma that could confound FIV calculation were used to derive the correlations between baseline core and FIV. FIV was measured on MRI (n=150) and CT (n=14).

Results: A total of 164 patients were included (mean age, 66±13.14 years; baseline NIHSS, 14.93±6.73; median time from CTP to reperfusion; median 86.5 IQR [61.25-111.75] min). The median baseline rCBF<30% lesion was 4.5 [0-21]cc and 10.4 [0-36]cc on Rapid and Viz.ai, respectively. There was a strong correlation across all baseline perfusion parameters: rCBF<30%: R=0.813; Tmax>6: R=0.879, Tmax>8: R=0.866, Tmax>10: R=0.852. In addition, there was a highagreement rate for binary values for qualification for the DAWN (core≤21 cc: 88.9%; ≤31cc: 82.4%; ≤51cc: 89.1%), DEFUSE-3 (93%), and EXTEND (91) trials. A total of 148 patients were fully reperfused (mTICI2c-3). Their median FIV was 23.72 [11.0-78.2] cc. There was only a marginal correlation between rCBF<30% and FIV which not significantly different across the two platforms (RAPID: R=0.456; Viz.ai R=0.437, p<0.001).

Conclusion: The RAPID and Viz-AI software have a strong correlation in terms of the overall baseline parameters and reperfusion treatment eligibility. In fully reperfused patients, the prediction of FIV was only marginal with both softwares.

Preclinical evaluation of the ANCD thrombectomy device: safety and efficacy in a swine clot model

BACKGROUND

The Advanced Thrombectomy System (ANCD) provides a new funnel component designed to reduce clot fragmentation and facilitate retrieval in patients with stroke by locally restricting flow, allowing distal aspiration in combination with a stent retriever (SR).

OBJECTIVE

To evaluate the preclinical efficacy and safety of the ANCD in a swine clot model.

METHODS

Soft and firm clots were implanted in the lingual and cervical arteries of 11 swine to obtain Thrombolysis in Cerebral Infarction (TICI) 0 blood flow. Mechanical thrombectomy was performed with either a balloon guide catheter+Solitaire 2 stent retriever (BGC+SR, n=13) or ANCD+SR (n=13). TICI flow was evaluated and successful revascularization was defined as TICI 3 (normal perfusion). To characterize safety, a total of 3 passes were performed in each vessel independent of recanalization. Tissues were explanted for histopathological analysis after 3 and 30 days, respectively.

RESULTS

First pass reperfusion rates were ANCD+SR: 69% and BGC+SR: 46%. Reperfusion increased after the third pass in both groups (ANCD+SR: 100%, vs BGC+SR: 77%). Recanalization was achieved after an average of 1.4 and 1.9 passes in ANCD+SR and BGC+SR (p=0.095), respectively. Vessel injury was comparable in both groups; endothelial loss at 3 days was the most common injury seen (ANCD+SR: 1.78±1.22; BGC+SR: 2.03±1.20; p=0.73), while other histopathological markers were absent or minimal. Tissues downstream from targeted vessels also showed absence or minimal lesions across both groups.

CONCLUSIONS

Results in a swine clot model support the high efficacy of the ANCD+SR without causing clinically significant vessel injury potentially related to the new funnel component.

Endovascular management of acute large vessel occlusion stroke in pregnancy is safe and feasible

INTRODUCTION

Stroke is a leading cause of adult death and disability. Although acute ischemic stroke (AIS) in pregnancy is rare, it has devastating consequences on the life of the mother and fetus. Pregnancy was an exclusion criterion in endovascular thrombectomy (EVT) trials and so there are no evidence-based treatment recommendations in this subgroup. The objective of this study was to evaluate the safety and feasibility of mechanical thrombectomy in large vessel occlusion (LVO) stroke in pregnancy.

METHODS

Patients with AIS due to LVO treated with EVT during pregnancy between 2000 and 2019 were identified at seven tertiary care centers. After IRB approval, retrospective analysis of prospectively maintained stroke/endovascular databases was performed.

RESULTS

A total of seven subjects were identified. The average age was 33.2 years (range 25-38 years) and the average initial National Institutes of Health Stroke Scale (NIHSS) score at presentation was 15 (range 9-28). Three patients received IV tissue plasminogen activator. Techniques of EVT included stent retriever thrombectomy, stent retriever-assisted continuous aspiration, direct contact aspiration, and multimodal techniques including a rescue balloon mounted coronary stent placement. While one patient was noted to have petechial hemorrhage, no individuals developed parenchymal hematoma. Mean discharge NIHSS score was 1.7 (range 0-5).

CONCLUSION

EVT is a safe and effective treatment for acute stroke secondary to LVO in this series of pregnant patients. While EVT for acute stroke is standard of care in select patient populations, our study suggests that treatment should be considered in the gravid population.

ANCD thrombectomy device: in vitro evaluation

Introduction

Endovascular treatment of stroke, although highly effective, may fail to reach complete recanalization in around 20% of cases. The Advanced Thrombectomy System (ANCD) is a novel stroke thrombectomy device designed to reduce clot fragmentation and facilitate retrieval by inducing local flow arrest and allowing distal aspiration in combination with a stent retriever. We aimed to assess the preclinical efficacy of ANCD.

Methods

Soft red blood cell (RBC)-rich (n=20/group) and sticky fibrin-rich (n=30/group) clots were used to create middle cerebral artery (MCA) occlusions in two vascular phantoms. Three different treatment strategies were tested: (1) balloon guide catheter + Solitaire (BGC+SR); (2) distal access catheter + SR (DAC+SR); and (3) ANCD+SR, until complete recanalization was achieved or to a maximum of three passes. The recanalization rate was determined after each pass.

Results

After one pass, ANCD+SR resulted in an increased recanalization rate (94%) for all clots together compared with BGC+SR (66%; p<0.01) or DAC+SR (80%; p=0.04). After the final pass the recanalization rate increased in all three groups but remained higher with ANCD+SR (100%) than with BGC+SR (74%; p<0.01) or DAC+SR (90%; p=0.02). The mean number of passes was lower with ANCD+SR (1.06) than with BGC+SR (1.46) or DAC+SR (1.25) (p=0.01). A logistic regression model adjusted for treatment arm, clot type, and model used showed that both RBC-rich clots (OR 8.1, 95% CI 1.6 to 13.5) and ANCD+SR (OR 3.9, 95% CI 1.01 to 15.8) were independent predictors of first-pass recanalization.

Conclusion

In in vitro three-dimensional models replicating MCA-M1 occlusion, ANCD+SR showed significantly better recanalization rates in fewer passes than other commonly used combinations of devices.

Effect of extracranial lesion severity on outcome of endovascular thrombectomy in patients with anterior circulation tandem occlusion: analysis of the TITAN registry

Introduction

Endovascular treatment (EVT) for tandem occlusion (TO) of the anterior circulation is complex but effective. The effect of extracranial internal carotid artery (EICA) lesion severity on the outcomes of EVT is unknown. In this study we investigated the effect of EICA lesion severity on the outcomes of tandem occlusion EVT.

Methods

A multicenter retrospective TITAN (Thrombectomy In TANdem lesions) study that included 18 international endovascular capable centers was performed. Patients who received EVT for atherosclerotic TO with or without EICA lesion intervention were included. Patients were divided into two groups based on the EICA lesion severity (high-grade stenosis (≥90% North American Symptomatic Carotid Endarterectomy Trial) vs complete occlusion). Outcome measures included the 90-day clinical outcome (modified Rankin Scale score (mRS)), angiographic reperfusion (modified Thrombolysis In Cerebral Ischemia (mTICI) at the end of the procedure), procedural complications, and intracranial hemorrhage at 24 hours follow-up.

Results

A total of 305 patients were included in the study, of whom 135 had complete EICA occlusion and 170 had severe EICA stenosis. The EICA occlusion group had shorter mean onset-to-groin time (259±120 min vs 305±202 min; p=0.037), more patients with diabetes, and fewer with hyperlipidemia. With respect to the outcome, mTICI 2b–3 reperfusion was lower in the EICA occlusion group (70% vs 81%; p=0.03). The favorable outcome (90-day mRS 0–2), intracerebral hemorrhage and procedural complications were similar in both groups.

Conclusion

Atherosclerotic occlusion of the EICA in acute tandem strokes was associated with a lower rate of mTICI 2b–3 reperfusion but similar functional and safety outcomes when compared with high-grade EICA stenosis.