Recanalization Rate Research Articles

Double anterograde/retrograde approach for embolization of pulmonary arteriovenous malformation presenting with acute respiratory failure.

A 54-year-old male with multiple cardiovascular risk factors and past medical history of long-standing dyspnea was admitted for acute respiratory failure. Physical examination revealed near-normal blood pressure, sinus tachycardia, tachypnea, and reduced oxygen saturation (90%) with mild distal-limb cyanosis. On admission ECG, chest X-ray, transthoracic echocardiography, and laboratory tests were performed to exclude new-onset heart failure and/or an acute coronary syndrome. Then, he underwent pulmonary CT angiography seeking for pulmonary embolism that showed a voluminous pulmonary arterio-venous malformation (PAVM) with the feeding artery coming from the right pulmonary artery and venous drainage confluent into the right pulmonary vein (Panel 1A and C). A thrombophilic screening showed a heterozygous mutation for the methylenetetrahydrofolate reductase-1 gene and reduced serum-free protein S levels. The invasive left–right heart catheterization revealed mild-to-moderate pulmonary hypertension and moderate arterial desaturation (O2 saturation, 91%). Considering the large size of both the feeding artery and vein drainage (10 mm) and in order to reduce postprocedural embolization risk and recanalization rate,1,2 a contemporary percutaneous embolization of both PAVM branches (Panel 1C and D; Supplementary material online, Videos S1–3) with two Amplatzer Vascular Plug (AVP) II® 20 mm (Abbott, Plymouth, MN, USA) was planned using a double access technique, transfemoral trans-septal (retrograde) and transfemoral transpulmonary (anterograde) with a post-procedural improvement of arterial saturation (up to 99%). The patient was discharged with a marked clinical improvement (NYHA Class I) and complete exclusion of the PAVM at six months follow-up (Panel 1E and F).

The effect of operator's experience on mechanical thrombectomy outcomes: A systematic review.

Mechanical thrombectomy (MT) has become the standard of care for stroke patients. The majority of the clinical trials and publications analyzing the outcomes related to the procedures report interventional performance by experienced practitioners. However, few of them individualize their preliminary metrics according to the operator's experience. To summarize the literature and report safety and efficacy outcomes following MT procedures and correlate them with the operator's experience. Primary outcomes were successful recanalization, defined as modified thrombolysis in cerebral infarction greater or equal to 2b or 3, duration of the procedure measured in minutes, and serious adverse event. This systematic review was performed according to the PRISMA guidelines. The PubMed, Embase, and Cochrane databases were utilized. There were six studies comprising 9348 patients (mean age 69.8 years; 51.2% males), and 9361 MT procedures were included. Each publication used for this review used a different experience definition to report their data. Higher interventionists' experience demonstrated a positive relationship with the possibility of successful recanalization and an inverse relationship with the duration needed for the operation in almost all of the included studies. As for the complications, none of the authors reported a statistically significant risk reduction of an adverse event, except Olthuis et al. correlating increasing training with lower odds of stroke progression. A higher experience level is associated with better recanalization rates and shorter procedural duration in MT operations. Further studies are warranted to define the minimum required level of experience for operational autonomy.

Do treatment methods for deep vein thrombosis have different effects on post-thrombotic syndrome and the quality of life?

This study aimed to compare the effects of interventional methods and medical therapy in patients with acute proximal deep vein thrombosis (DVT) on the risk of development of post-thrombotic syndrome (PTS) and the quality of life during the follow-up period. Clinical statuses of the patients who were treated medical therapy alone or medical therapy and endovascular treatment for acute proximal (iliofemoral-popliteal) DVT between 1st January 2014 and 1st November 2022 were reviewed retrospectively. The study included 128 patients who received interventional treatment (Group I) and 120 patients who received medical therapy alone (Group M). The mean age of the patients was 52.98 ± 12.45years in Group I and 55.60 ± 16.15years in Group M. Patients were classified as provoked or unprovoked and by LET scale (lower extremity thrombosis level scale). Patients were followed-up for 1year using Villalta scores and VEINES-QoL/Sym questionnaire. LET scale was evaluated based on the results of lower extremity venous Doppler ultrasound (DUS). No early acute phase mortality was observed. LET classification showed that there is higher proximal involvement in Group I (Table 1[Table: see text]). Recurrence rate was 6.25% (8 patients) in Group I and 21.66% (26 patients) in Group M (p < .001). Pulmonary embolism was not observed in either group. At 12-month follow-up, the number of patients with a Villalta score of ≥5 was 8 (6.25%) in Group I and 81 (67.5%) in Group M (p < .001), while the mean VEINES-QoL/Sym scale score was found to be 72.5 ± 6.35 in Group I and 40.2 ± 9.31 in Group M (p < .001). The rates of anticoagulant-associated bleeding were 3.12% (4 patients) in Group I and 6.66% (8 patients) in Group M. The mean complete recanalization rates calculated using DUS at year 1 was found to be 63.28% (81 patients) in Group I and 9.16% (11 patients) in Group M (p < .001). When deep vein thrombosis is treated using interventional methods, lower Villalta scores are detected after 1year of follow-up. Development of post-thrombotic syndrome is reduced substantially. According to VEINES-QoL/Sym quality of life (QoL) scale, QoL is higher in patients who underwent interventional procedures. Interventional treatment provides persistent benefit in the short and medium terms especially in DVT with proximal involvement.

Platelet-targeted thrombolysis for treatment of acute ischemic stroke.

Thrombolysis with tissue-type plasminogen activator (tPA) remains the main treatment for acute ischemic stroke. Nevertheless, tPA intervention is limited by a short therapeutic window, low recanalization rates, and a risk of intracranial hemorrhage (ICH), highlighting the clinical demand for improved thrombolytic drugs. We examined a novel thrombolytic agent termed "SCE5-scuPA," comprising a single-chain urokinase plasminogen activator (scuPA) fused with a single-chain antibody (SCE5) that targets the activated glycoprotein IIb/IIIa platelet receptor, for its effects in experimental stroke. SCE5-scuPA was first tested in a whole blood clot degradation assay to show the benefit of platelet-targeted thrombolysis. The tail bleeding time, blood clearance, and biodistribution were then determined to inform the use of SCE5-scuPA in mouse models of photothrombotic stroke and middle cerebral artery occlusion against tenecteplase. The impacts of SCE5-scuPA on motor function, ICH, blood-brain barrier (BBB) integrity, and immunosuppression were evaluated. Infarct size was measured by computed tomography imaging and magnetic resonance imaging. SCE5-scuPA enhanced clot degradation exvivo compared with its nonplatelet-targeting control. The maximal SCE5-scuPA dose that maintained hemostasis and a rapid blood clearance was determined. SCE5-scuPA administration both before and 2 hours after photothrombotic stroke reduced the infarct volume. SCE5-scuPA also improved neurologic deficit, decreased intracerebral blood deposits, preserved the BBB, and alleviated immunosuppression poststroke. In middle cerebral artery occlusion, SCE5-scuPA did not worsen stroke outcomes or cause ICH, and it protected the BBB. Our findings support the ongoing development of platelet-targeted thrombolysis with SCE5-scuPA as a novel emergency treatment for acute ischemic stroke with a promising safety profile.

General Anesthesia Compared With Non-GA in Endovascular Thrombectomy for Ischemic Stroke: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Endovascular thrombectomy (EVT) for large vessel occlusion ischemic stroke is either performed under general anesthesia (GA) or with non-GA techniques such as conscious sedation or local anesthesia alone. Previous small meta-analyses have demonstrated superior recanalization rates and improved functional recovery with GA when compared with non-GA techniques. The publication of further randomized controlled trials (RCTs) could provide updated guidance when choosing between GA and non-GA techniques. A systematic search for trials in which stroke EVT patients were randomized to GA or non-GA was performed in Medline, Embase, and the Cochrane Central Register of Controlled Trials. A systematic review and meta-analysis using a random-effects model was performed. Seven RCTs were included in the systematic review and meta-analysis. These trials included a total of 980 participants (GA, N = 487; non-GA, N = 493). GA improves recanalization by 9.0% (GA 84.6% vs non-GA 75.6%; odds ratio [OR] 1.75, 95% CI 1.26-2.42, p = 0.0009), and the proportion of patients with functional recovery improves by 8.4% (GA 44.6% vs non-GA 36.2%; OR 1.43, 95% CI 1.04-1.98, p = 0.03). There was no difference in hemorrhagic complications or 3-month mortality. In patients with ischemic stroke treated with EVT, GA is associated with higher recanalization rates and improved functional recovery at 3 months compared with non-GA techniques. Conversion to GA and subsequent intention-to-treat analysis will underestimate the true therapeutic benefit. GA is established as effective in improving recanalization rates in EVT (7 Class 1 studies) with a high Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) certainty rating. GA is established as effective in improving functional recovery at 3 months in EVT (5 Class 1 studies) with a moderate GRADE certainty rating. Stroke services need to develop pathways to incorporate GA as the first choice for most EVT procedures in acute ischemic stroke with a level A recommendation for recanalization and level B recommendation for functional recovery.

Initial Experience Using the New pHLO 0.072-inch Large-Bore Catheter for Direct Aspiration Thrombectomy in Acute Ischemic Stroke.

A direct aspiration, first pass technique (ADAPT) has been introduced as a rapid and safe thrombectomy strategy in patients with intracranial large vessel occlusion (LVO). The aim of the study is to determine the technical feasibility, safety, and functional outcome of ADAPT using the newly released large bore pHLO 0.072-inch aspiration catheter (AC; Phenox). We performed a retrospective analysis of data collected prospectively (October 2019-November 2021) from 2 comprehensive stroke centers. Accessibility of the thrombus, vascular recanalization, time to recanalization, and procedure-related complications were evaluated. National Institutes of Health stroke scale scores at presentation and discharge and the modified Rankin scale (mRS) score at 90 days post-procedure were recorded. Twenty-five patients (14 female, 11 male) with occlusions of the anterior circulation were treated. In 84% of cases, ADAPT led to successful recanalization with a median procedure time of 28 minutes. In the remaining cases, successful recanalization required (to a total of 96%; modified thrombolysis in cerebral infarction score 2b/3) the use of stent retrievers. No AC-related complications were reported. Other complications included distal migration of the thrombus, requiring a stent-retriever, and symptomatic PH2 hemorrhage in 16% and 4%, respectively. After 3 months, 52% of the patients had mRS scores of 0-2 with an overall mortality rate of 20%. Results from our retrospective case series revealed that thrombectomy of LVOs with pHLO AC is safe and effective in cases of large-vessel ischemic stroke. Rates of complete or near-complete recanalization after the first pass with this method might be used as a new benchmark in future trials.

Efficacy and safety of bridging therapy and direct mechanical thrombectomy in large vessel occlusions: a meta-analysis.

Efficacy and safety of bridging therapy and direct mechanical thrombectomy in large vessel occlusions: a meta-analysis.

The Effect of Smoking Cessation on the Technical Success of Endovascular Treatment for Thromboangiitis Obliterans

PurposeTo show that smoking cessation improves the technical success of lower extremity endovascular treatment in patients with thromboangiitis obliterans (TAO), or Buerger disease. Materials and MethodsOne hundred two patients with TAO who underwent endovascular treatment for chronic limb-threatening ischemia or severe claudication of lower extremities in a tertiary hospital between 2015 and 2022 were included in this retrospective study. Data on serum cotinine levels were available for the last 45 patients, and 38 patients constituted the study population. Per the institution’s protocol, patients were instructed to quit smoking 15 days before the intervention. However, cotinine levels showed that some of the patients continued smoking. Technical and recanalization successes were assessed as the primary end points. The secondary end point was the improvement in Rutherford scores at the 1-month follow-up. The McNemar test was used to compare the proportion of recanalized arteries after the intervention. ResultsThirty-seven men and 1 woman (mean age, 42.9 years ± 10.1) were evaluated. The overall technical success rate was 86.8% in the study group. The technical success rate was significantly higher in the nonsmoker group (n = 24 [96%]) than in the smoker group (n = 8 [61.5%]; P = .006). One-month clinical data were available for 100% of the patients. The Rutherford category of the nonsmoker group was significantly lower at the 1-month follow-up. In addition, the Wilcoxon signed-rank test revealed lower Rutherford scores after the intervention in the nonsmoker group. The adverse event rate was 8%. One (2.7%) patient in the smoker group underwent a minor amputation. ConclusionsCessation of smoking before endovascular therapy improved technical success and recanalization rates in patients with TAO.

Evaluation of Low-Molecular-Weight Heparin for Treatment of Portal Vein Thrombosis in Liver Cirrhosis Patients

Background and Objectives: Even though low-molecular-weight heparin (LMWH), including dalteparin, has a critical role in portal vein thrombosis (PVT) treatment in liver cirrhosis (LC) patients, the predictive factors and the proper dose of dalteparin for PVT treatment and relapse have not yet been investigated. Materials and Methods: This retrospective study evaluated the records of LC patients receiving dalteparin from July 2013 to June 2019. The odds ratio (OR) and adjusted OR were calculated from univariate and multivariable analyses, respectively. Results: Among data from 121 patients, the overall recanalization rate of all patients was 66.1% (80 patients). No history of variceal bleeding (OR 4.6, 95% CI: 1.88-11.43) and the case of newly developed thrombus before dalteparin treatment (OR 3.2, 95% CI: 1.24-8.08) were predictive factors associated with increased treatment response. Relapse of PVT occurred in 32 out of 80 patients (40%) who showed a recanalization. The risk of relapse was 3.1-3.9 times higher in those who took more than three months or more than six months from the diagnosis of PVT to dalteparin treatment compared to those who took less than these durations, respectively. In the dosing regimen, patients with the kg-based dosing regimen showed 2.6 times better response than those with the fixed dosing regimen. However, no difference in bleeding complications was observed. Conclusion: In the dosing regimen, the kg-based regimen that was the same as the venous thromboembolism regimen was a better option for the efficacy and safety of dalteparin therapy. Additionally, when treating PVT in LC patients, careful monitoring is recommended for patients with predictive factors for treatment response and relapse of PVT.

Defining the optimal size of an aspiration catheter in relation to the arterial diameter during mechanical thrombectomy for stroke

BackgroundMechanical thrombectomy for acute ischemic stroke is effective and includes different technical approaches. Operators use direct aspiration, a stent retriever, or a combination of both. Direct aspiration can be performed with various catheters of different sizes depending on the diameter of the occluded vessel. PurposeWe studied the relationship between the catheter diameter in regards to the occluded vessel diameter and the rate of successful recanalization. Materials and methodsWe conducted a retrospective, monocentric study on a series of consecutive patients treated with mechanical thrombectomy. For each procedure, we extracted each attempt that used direct aspiration and rated the attempt as successful or unsuccessful. We also measured the occluded artery diameter and calculated the ratio between the occluded artery and the aspiration catheter diameters. We tested the association between the diameter ratio and the recanalization status. We also performed inter-rater agreement for the arterial diameter measurement between three interventional neuroradiologists. ResultsWe included 119 patients with 201 attempts of direct aspiration. A higher diameter ratio was associated with a higher recanalization rate. The analysis in terciles showed that the odds of success were 4.80 higher when the ratio was >0.71 vs <0.54 (p < 0.01). Inter-rater agreement showed near-perfect intraclass correlation with 0.93 (0.91–0.94) consistency and 0.92 (0.90–0.94) absolute agreement. ConclusionsWe demonstrated an association between higher recanalization and a diameter of ratio >0.71 between the aspiration catheter and the occluded artery. These results could guide intraoperative decisions regarding the appropriate selection of aspiration catheters during mechanical thrombectomy increasing the rate of successful recanalisation. A larger study could provide additional data to further specify the optimal ratio.

Good collaterals and better outcomes after EVT for basilar artery occlusion: A systematic review and meta-analysis.

Stroke caused by acute basilar artery occlusion (BAO) is devastating with high dependency and mortality. Recent trials have demonstrated the efficacy of endovascular treatment (EVT) for acute BAO, while pretreatment collaterals may be a valuable prognostic indicator for post-EVT outcomes. To systematically review and synthesize evidence on the associations between pretreatment collateral status and outcomes after EVT in acute BAO. We retrieved relevant full-text articles published in English since 1 January 2010, reporting associations between pretreatment collateral status and outcomes after EVT for BAO, by searching MEDLINE and Embase. The primary outcome was favorable or good 90-day functional outcome (modified Rankin Scale [mRS] 0-2 or 0-3); secondary outcomes included successful recanalization, symptomatic intracranial hemorrhage, final infarct volume, and 90-day mortality. Risk ratios (RRs) with 95% confidence intervals (CIs) for good versus poor collaterals on the outcomes were synthesized using random-effects models. Subgroup and sensitivity analyses were conducted for the primary outcome. Overall, 29 primary studies (2995 participants) were included in qualitative review, among which 16 studies (1447 participants) were meta-analyzed. With different imaging modalities and methods to grade the collateral status, good collaterals were found in 33-85% of patients in the individual primary studies (I2 = 95.2%, p < 0.001), with a pooled proportion of 51% (95% CI: 40-62%) across all studies. Good pretreatment collaterals were associated with a doubled rate of favorable/good 90-day functional outcome (RR = 2.03, 95% CI: 1.63-2.51, p < 0.001), a higher rate of successful recanalization (RR = 1.23, 95% CI: 1.04-1.45, p = 0.015), and reduced 90-day mortality (RR = 0.59, 95% CI: 0.43-0.81, p = 0.001) after EVT for BAO. None of the primary studies reported the associations of good collaterals with the other secondary outcomes. Subgroup analyses revealed possibly more prominent protective effect of good pretreatment collaterals over the primary outcome, in studies with longer time windows in patient eligibility criteria for EVT (p = 0.028 for between-subgroup heterogeneity). In patients with BAO receiving EVT, good pretreatment collateral status was associated with a higher chance of favorable 90-day functional outcome, despite the various methods in grading the collateral circulation. Efforts are needed for more standardized collateral assessment in BAO, for more reliable and generalizable investigations of its clinical implications.

Abstract 98: The Impact Of Aspiration Catheter Size On Thrombectomy Outcomes Using Adapt Technique-analysis From The STAR Registry

Introductions: Clinical trials have shown that aspiration thrombectomy is as safe and effective as stent-retriever thrombectomy. Multiple improvements have been made to the aspiration technique over the last few years. In this study, we aim to assess the effect of aspiration catheter bore size on the outcomes of A direct aspiration first pass technique (ADAPT) thrombectomy. Methods: We included patients who underwent ADAPT thrombectomy for M1 or internal carotid artery terminus (ICA-T) occlusions in the Stroke Thrombectomy and Aneurysm (STAR) database. Patients included between July 2016 and July 2022. We compared baseline characteristics, procedural metrics and outcomes between patients who underwent thrombectomy using small bore (0.035”-0.060”), medium bore (0.062”-0.068”) and large bore (0.070”-0.074”) catheters. Results: A total of 1158 patients were included; 576 (49.7%) females, 645 (70%) White, and 464 (40.6%) received IV-tPA. No difference was noticed in age, sex, and vascular risk factors between the 3 different groups. There was higher rate of IV-tPA in the small-bore catheter group (48.8%) compared to the medium and large bore catheter groups (38.4% and 36.7%, respectively) (P=0.03). Procedure duration was shorter when using medium (20 min) and large (18 min) compared to small bore catheters (30 min) (P=0.01). Both medium and large bore catheters were associated with higher rate of successful recanalization (88.9% and 87.9%, respectively) compared to small bore catheters (81.6%) (P=0.010). However, the difference in successful recanalization or procedure duration between medium and large bore catheters was not significant. No difference was noted in the rate of symptomatic hemorrhagic transformation (sICH) (4.7%, 5.3%, and 7.1%; P=0.345), 90-day favorable outcome (modified Rankin Scale 0-2) (41.8%, 39.3%, 40.8%; P=0.766) or 90-day mortality (18.1%, 23.5%, 24.4%; P=0.111) between the groups. Conclusions: Higher rate of successful recanalization and shorter procedure duration were observed when using medium and large bore aspiration catheters compared with small bore catheters in ADAPT technique. However, these procedural benefits were not observed when comparing large bore to medium bore catheters.

Abstract 122: The P2x4 Inhibitor, Paroxetine Dramatically Prevents Not Only Growth Of Unruptured Cerebral Aneurysms But Also Recanalization After Aneurysm Coil Embolization; A Retrospective Clinical Study, Drug For Aneurysm Study

Introduction: We have suggested that inhibition of P2X4 purinoceptor, which is involved in the endothelial flow sensing mechanism, prevents cerebral aneurysm development and growth in an animal model. Therefore, we retrospectively investigated whether a P2X4 inhibitor, paroxetine used as an antidepressant, has an inhibitory effect on the growth of unruptured cerebral aneurysms and the rate of recanalization after coil embolization. Methods: Among the cases registered in the J-ASPECT Study, the Japanese stroke inpatient reimbursement database, from 2010 to 2019, we searched for cases who were taking paroxetine and with registered unruptured cerebral aneurysm or had undergone cerebral aneurysm coil embolization. We then invited medical centers with these cases to participate in the study and enrolled cases that met the selection criteria by referring to the imaging data and patient background of the cases. The inhibitory effect in the paroxetine-treated group was compared with that of the control group in a multivariate analysis after adjustment for age, gender, and known risk factors. Results: There were 708 cases at 226 facilities nationwide that were potentially matched in the criteria. Seventy-four facilities participated, of which 74 cases at 45 facilities met the selection criteria. A total of 700 control cases were enrolled from 14 core participating centers. The rate of growth incidence of aneurysms was 0.0318 for paroxetine-treated cases (n=36) and 0.0960 for control cases (397). The significant factors (regression coefficients) were paroxetine (-2.26), specific sites of occurrence (-1.28), shape irregularity (1.63), age (0.11), female (1.54), hypertension (-0.55), statin (0.87), and family history of stroke (0.71). The significant factors (odds ratios) in recanalization after 1 year of coil embolization were paroxetine (0.21), complete embolization (0.26), ruptured aneurysm (3.95), and size (1.14). Conclusions: This retrospective study suggests that P2X4 inhibitors including paroxetine may be clinically applicable as agents to inhibit the growth of unruptured cerebral aneurysms and recanalization after 1 year of aneurysm coil embolization. The use of reimbursement information may be useful when collecting very rare cases.

Abstract TP6: Recanalization Of Large Vessel Occlusion After Intravenous Alteplase Therapy In Acute Ischemic Stroke Patients Transferred From Primary Stroke Centers

Background and Purpose: Early recanalization of occluded intracranial arteries predicts favorable outcome in acute ischemic stroke (AIS) patients treated with intravenous alteplase therapy within 4.5 hours from stroke onset. Prior studies have shown recanalization of large vessel occlusion (LVO) with alteplase ranging from 0% for internal carotid artery and 33% for distal blood vessels. We performed an analysis to examine the characteristics of stroke patients and the location of LVO that predicts early recanalization in patients treated with intravenous alteplase alone. Methods: This single-center, retrospective study solely included AIS patients with LVO who were transferred to our institution for mechanical thrombectomy evaluation after treated with alteplase at a primary stroke center between January 2019 and January 2021. Recanalization was identified by repeated computed tomographic angiography (CTA) or digital subtraction angiography (DSA) at our institution upon arrival. Results: One hundred and six patients were included in the analysis, 15 (14.1%) patients had partial or complete recanalization of LVO. Cardioembolic was the most common cause of ischemic stroke (46%), followed by large vessel atherosclerosis (33%) in this group. They were more likely to have a medical history of hypertension (73.3% vs. 59.3%), better baseline function as measured by pre-modified Rankin Score 0-2 (73.3% vs. 68.1%), and receive early treatment (105 minutes vs. 135 minutes), compared to their counterparts with no recanalization. Proximal and distal middle cerebral artery had the same rate of recanalization in this cohort. Conclusion: The highest incidence of early recanalization of occluded intracranial arteries was found in cardioembolic strokes with middle cerebral artery being the most common location of recanalization. Early recanalization with intravenous alteplase was also associated with improved functional recovery at discharge.

Abstract TP13: Is Tenecteplase Associated Recanalization Dependent On Thrombus Length?

Introduction: Recent evidence supports that IV tenecteplase (TNK) is non-inferior to IV alteplase when administered to eligible patients with acute ischemic stroke (AIS). Studies suggest that alteplase does not effectively lyse clots ≥ 8mm. However, the neurovascular characteristics of TNK are rapidly evolving. The aim of this study was to evaluate the efficacy of TNK in clot lysis ≥ 8mm as measured by hyperdense sign on CT for internal carotid artery (ICA) and middle cerebral artery (MCA M1 and M2 segment) occlusion. Methods: We conducted a retrospective cohort study of prospectively collected AIS patients who presented to our comprehensive stroke center, received TNK, and had hyperdense sign on CT head. Hyperdense signs were detected using 0.625 mm slices in retrospective fashion, blinded to the clinical scenario with regards to laterality. Revascularization was defined as modified Thrombolysis in Cerebral Infarction (mTICI) score on first run of digital subtraction angiography prior to intervention, follow up CTA or MRA without large vessel occlusion (LVO), and/or with improved clinical symptoms that correlate with hyperdense sign. Social science statistics software was used for data analysis. Results: From October 2020 to June 2022, out of 77 AIS patients who received TNK, 25 subjects (≥ 8mm, n=19) had associated hyperdense signs. Mean age was 67.16 (95% CI 60.05, 74.27). Median NIHSS was 14 (95% CI 11.378, 19.50). Mean thrombus length was 17.64 mm (95% CI, 13.26, 22.02). Twenty-one percent (n=4) of 19 subjects with hyperdense signs ≥ 8mm recanalized post-TNK (n=3 angiography, n=1 MRA). Thirty-three percent (n=2) of 6 subjects with hyperdense signs &lt; 8mm recanalized post-TNK. There was not a statistically significant difference between recanalization rates in hyperdense signs ≥ 8mm or &lt; 8mm (Fisher exact test statistic=0.61). There was not a statistically significant difference between intracerebral hemorrhage rates in hyperdense signs ≥ 8mm or &lt; 8mm (Fisher exact test statistic=1). Conclusion: Our study suggests that tenecteplase may be associated with higher thrombolytic-related recanalization in thrombi measuring 8mm or greater as compared to historical alteplase experience. Larger, prospective studies are needed to corroborate our findings.

Abstract TP137: Rescue Angioplasty And/or Stenting For Acute Large Artery Occlusion Of Posterior Circulation With Underlying Intracranial Atherosclerosis

Background: Prior studies have shown rescue intracranial angioplasty and/or stenting (PTAS) is safe and efficacious in acute large vessel occlusion (LVO) of the anterior circulation with underlying intracranial atherosclerotic disease (ICAD). We investigated the safety and efficacy of acute intracranial angioplasty and/or stenting in patients with posterior circulation intracranial atherosclerosis-related occlusion (ICAS-O). Methods: Through the utilization of a prospectively collected endovascular database at a comprehensive stroke center between January 2016- May 2022, variables such as demographics, co-morbid conditions, symptomatic intracerebral hemorrhage (ICH), the mortality rate at discharge, and recanalization rate and favorable clinical outcome, modified thrombolysis in cerebral infarction score (mTICI) and favorable clinical outcome (modified Rankin Scale (mRS), were examined. The outcomes between acute PTAS + MT in the anterior and posterior circulation were compared. Results: There were a total of 75 acute ischemic stroke (AIS) patients who underwent rescue PTAS, of which 15 (20.0 %) were posterior circulation ICAS-O group. Baseline characteristics were similar between the groups except for gender (6.7 % vs 45.0) and atrial fibrillation (21.7% vs 0.0%). There was no statistical difference in discharge NIH Stroke Scale (mean, 18 vs 23%, P = 0.860) or favorable outcome (modified Rankin Scale ≤ 2) at 90 days (46.7% vs 38.7 %, P = 0.477) between the posterior and anterior ICAS-O groups respectively. Symptomatic ICH rate tended to be higher in the anterior group (11.7 vs 6.7%, P = 0.495). Conclusions: Rescue angioplasty and/or stenting seem safe treatment options for posterior circulation ICAS-related LVO. Further larger multicenter prospective studies are required to corroborate the results of our study.

Abstract WP36: Transcranial Electrical Stimulation (tdcs) In Stroke Early After Onset Clinical Trial (tesseract)

Background: In preclinical studies of acute ischemic stroke (AIS), cathodal transcranial direct current stimulation (C-tDCS) provides neuroprotection by inhibiting peri-infarct depolarization, apoptotic and inflammatory cascades, and by enhancing collateral perfusion. We undertook the first-in-human feasibility study of high-definition (HD) C-tDCS as an individualized treatment strategy in AIS. Method: The study design was a randomized, sham-controlled, 3+3 dose-escalation feasibility trial. Key entry criteria were patients within 24hr from AIS onset, imaging evidence of cortical-supplying vessel occlusion and substantial penumbra, and ineligibility for reperfusion therapies. HD C-tDCS was delivered to the penumbra using individualized montages. Current flow models showed the specificity of electrical field coverage to ischemic regions. Results: Among 10 enrolled patients, 7 were allocated to active C-tDCS and 3 sham. Age in active/sham patients was 75 (±19.6) vs 77 (±12); entry NIHSS in active/sham patients was 8 (±8.5) vs 7(±2.6). The first 4 patients (3 active and 1 sham) received 1mA-20min (Tier1) and the subsequent 6 (4 active and 2 sham) 2mA-20min (Tier2) of C-tDCS. All patients completed the stimulation with no significant intolerability. C-tDCS met the study primary feasibility endpoint, with speed of tDCS implementation median 12.5 min (IQR 9-15) in the last 4 patients. One symptomatic intracranial hemorrhage occurred due to a ruptured mycotic aneurysm for which Tier 2 was extended. Median penumbral salvage proportion in the active C-tDCS group was 66% (IQR 29-80.5) compared to 0% (IQR 0-0) in sham. Recanalization rate was 83% in active vs 33% in sham (Figure). Conclusion: High-definition C-tDCS is a feasible non-invasive targeted treatment for AIS and showed strong signals of beneficial effects upon penumbral salvage and vessel recanalization. These data warrant conduct of large efficacy and safety trials of C-tDCS as an AIS therapy.

Abstract TP133: Efficacy Of Mechanical Thrombectomy For The Posterior Circulation Stroke

Background and Purpose: The efficacy of mechanical thrombectomy (MT) for posterior circulation large vessel occlusions has not been fully elucidated. We investigated the efficacy and safety of MT for posterior circulation stroke (PCS) compared with anterior circulation stroke (ACS). Methods: We analyzed 885 consecutive patients who underwent MT for acute ischemic stroke between January 2013 and December 2020 at six comprehensive stroke centers. The patients were divided into two groups; the PCS and ACS group. The procedural and clinical outcomes were compared between the groups. Results: A total of 767 patients (PCS group, 83; ACS group, 684), were analyzed. PCS patients were significantly younger (75 vs. 79, P = 0.008) and had a higher NIHSS score at baseline (23 vs 19, p=0.012) and longer door to puncture time (97 vs 73 min, p=0.009). The rate of male (67.0 vs 46.9% p&lt;0.001) and atherosclerotic brain infarction (22.8 vs 8.3% p&lt;0.001) were higher, comorbid atrial fibrillation (50.6 vs 64.4% p=0.022) was fewer in the PCA group. The rate of mTICI 3 recanalization at the first pass (40.9 vs 28.5% p=0.019) was significantly higher in the PCS group. However, the rates of final mTICI ≥ 2b recanalization (86.6 vs 83.8% p=0.491), symptomatic hemorrhagic complications, good clinical outcome at 90 days (34.3 vs 32.5% p=0.767), and mortality (22.3 vs 16% p=0.184) were similar in the groups. In the PCS group, the single use of a stent retriever for the first pass was associated with higher mortality rate compared with use of ADAPT or combined technique (38.6 vs 12.2% p=0.012). Conclusions: MT for PCS seemed to be beneficial, having similar complication, recanalization rate, and clinical outcomes with ACS.

Abstract TP138: The Effect Of Dominant Division Catheterization In Mechanical Thrombectomy On First Pass Effect And Clinical Outcome

Introduction: The middle cerebral artery (MCA M1 segment) bifurcates into anterior and posterior divisions (M2 segments) in 78% of the population. When feasible, preferential catheterization of the dominant division is performed during endovascular thrombectomy (EVT) in patients with acute ischemic strokes (AIS). Our aim was to evaluate the association of dominant division catheterization in EVT with first pass effect and clinical outcome. Methods: Retrospective chart review of AIS patients presenting to our comprehensive stroke center with AIS secondary to MCA M1 and/or internal carotid artery (ICA) terminus occlusions who underwent standardized EVT defined as proximal flow arrest, distal aspiration, and stent retriever. Patients receiving intra-arterial thrombolytics and/or non-thrombolytics were excluded. Digital subtraction angiographic images were reviewed to determine if dominant M2 branch catheterization was performed on first pass. Modified Thrombolysis in Cerebral Infarction (mTICI) score and 90-day modified Rankin score (mRS) were evaluated. TICI score of 2B or greater was considered successful recanalization. mRS ≤ 2 was considered good clinical outcome. Social science statistics software was used for data analysis. Results: From June 2019 to November 2021, 126 patients with MCA M1 and/or ICA terminus occlusions who underwent standardized EVT, 76 met the inclusion criteria. Fifty were excluded as they had codominant M2 branches. Mean age was 72 (95% CI 68.69, 75.31) and median NIHSS was 18 (95% CI 16.16, 18.72). Thirty-eight percent (n=34) of subjects were male. Fifty-seven subjects underwent dominant division catheterization during first pass. First pass recanalization was significantly associated with catheterization of dominant branch (Fisher value: 0.0002). Catheterization of dominant branch during first pass was not associated with total number of passes (Fisher value: 0.17). Administration of IV thrombolytics prior to procedure (n=19) was not significantly associated with pre-procedure recanalization (Fisher value: 0.38). Conclusion: Our study suggests that catheterization of dominant branch during thrombectomy is associated with higher rates of first-pass successful recanalization.

Abstract WP134: Long-Term Spontaneous Recanalization Rates Of Symptomatic Cervical Carotid Artery Occlusions

Background: Long-term rates of spontaneous recanalization of a previously acutely symptomatic cervical internal carotid artery occlusion (ICAO) have not been well characterized. The purpose of this study was to determine the rate of ICAO recanalization after index transient ischemic attack (TIA)/stroke in patients with serial vessel imaging, and the clinical factors associated with recanalization. Methods: This was a single-center, retrospective analysis from 2012-2020 of patients presenting with TIA/stroke due to an acute cervical ICAO. Patients were included if follow-up neck vessel imaging (CTA, MRA or ultrasound) was performed after index TIA/stroke. Recanalization was classified as the presence of continuous flow within the cervical carotid artery on repeat imaging. Patients were excluded if they received catheterization of the occluded artery during index admission or if the occlusion was previously documented (i.e., chronic). Results: Fifty-five patients were included in this study (mean age 61 ± 12 years, 27% female). The most common etiology for cervical ICAO was atherosclerosis (71%), followed by dissection (22%). Twelve patients (22%) demonstrated recanalization on follow-up imaging at a median of 125 days from index TIA/stroke (range 2-1072 days). Three patients with recanalization underwent carotid revascularization with endarterectomy or stenting. The administration of intravenous alteplase during index stroke admission was associated with recanalization (p=0.008). However, discharge antithrombotic regimen (antiplatelet or anticoagulation) or the etiology of the occlusion were not associated with recanalization (p=0.48 and p=0.73, respectively). There was no difference in 6-month recurrent TIA/stroke rates between those with recanalization (1 patient, 8.3%) and those without recanalization (4 patients, 9.3%), p=1.0. Conclusion: Cervical ICAO recanalization occurred in 12 (22%) patients in our cohort at follow-up and allowed for carotid revascularization procedures in 3 (25%) of these patients. Outpatient follow-up cervical vessel imaging should be considered after symptomatic cervical ICAO, as identifying spontaneous recanalization can alter management.