Mechanical Thrombectomy Techniques Research Articles

MINT Registry: Rationale and Study Design

Background Mechanical thrombectomy has become the standard of care for treatment of acute ischemic stroke secondary to large‐vessel occlusion up to 24 hours from last known normal time. Multiple different techniques for mechanical thrombectomy have been described, including a direct aspiration first‐pass technique and stent retriever thrombectomy. With a direct aspiration first‐pass technique, classically, a large‐bore aspiration catheter is delivered over a microcatheter and microwire to the clot. Recently, a novel macrowire has been introduced as a potential alternative to the use of microwire–microcatheter to allow the delivery of the aspiration catheter. The aim of this study is to develop a multicenter registry comparing delivery of an aspiration catheter for intracranial thrombectomy for acute ischemic stroke secondary to emergent large‐vessel occlusion over a macrowire in comparison with traditional use of microcatheter and microwire. Methods MINT (Macrowire for Intracranial Thrombectomy) is a multicenter, observational study currently enrolling patients with large‐vessel occlusion who underwent mechanical thrombectomy using a macrowire to deliver the aspiration catheter to the intracranial occlusion. All the participating sites will screen and report cases on a monthly basis. The decision to use the macrowire and various aspiration catheters is at the discretion of the interventionalist. Results We will collect patient's clinical, demographic, and radiographic data. In addition, we plan to collect procedure variables and postprocedure clinical and imaging data. Outcomes include successful delivery of the reperfusion catheter to the clot interface, time taken from groin access to first pass, and a bailout strategy for thrombectomy in cases where this is not feasible. Conclusion The MINT registry will add to our understanding of safety and efficacy of this novel macrowire in intracranial thrombectomy. This registry will also highlight and allow for understanding in workflow improvements from simplifying setup and possibly cost effectiveness of this technique.

Mechanical Thrombectomy Workshops Improve Procedural Knowledge and Skills Among Neurointerventional Teams in Low- to Middle-Income Countries.

While mechanical thrombectomy (MT) is proven to be lifesaving and disability sparing, there remains a disparity in its access in low- to middle-income countries. We hypothesized that team-based MT workshops would improve MT knowledge and skills. We designed a 22-hour MT workshop, conducted as 2 identical events: in English (Jamaica, January 2022) and in Spanish (Dominican Republic, May 2022). The workshops included participating neurointerventional teams (practicing neurointerventionalists, neurointerventional nurses, and technicians) focused on acute stroke due to large vessel occlusion. The course faculty led didactic and hands-on components, covering topics from case selection and postoperative management to device technology and MT surgical techniques. Attendees were evaluated on stroke knowledge and MT skills before and after the course using a multiple choice exam and simulated procedures utilizing flow models under fluoroscopy, respectively. Press conferences for public education with invited government officials were included to raise stroke awareness. Twenty-two physicians and their teams from 8 countries across the Caribbean completed the didactic and hands-on training. Overall test scores (n=18) improved from 67% to 85% (P<0.002). Precourse and postcourse hands-on assessments demonstrated reduced time to completion from 36.5 to 21.1 minutes (P<0.001). All teams showed an improvement in measures of good MT techniques, with 39% improvement in complete reperfusion. Eight teams achieved a Thrombolysis in Cerebral Infarction score of 3 on pre-course versus 15 of 18 teams on post-course. There was a significant reduction in total potentially dangerous maneuvers (70% pre versus 20% post; P<0.002). Universally, the workshop was rated as satisfactory and likely to change practice in 93% Dominican Republic and 75% Jamaica. A team-based hands-on simulation approach to MT training is novel, feasible, and effective in improving procedural skills. Participants viewed these workshops as practice-changing and instrumental in creating a pathway for increasing access to MT in low- to middle-income countries.

Non-routine thrombectomy in pediatric arterial ischemic stroke.

Unlike in adults, the indications and techniques for mechanical thrombectomy for arterial ischemic stroke (AIS) in children are not clearly established. The medical and interventional management of children with acute large vessel occlusion may entail the modification of the standardized management of this condition in adults. We present six cases of children who underwent non-routine thrombectomy for AIS. We retrospectively reviewed the records of children diagnosed with AIS between 2015 and 2023 and evaluated patient characteristics, procedural technical data, and final clinical outcomes. Procedures deviating from the current definition and indications for AIS treatment in adults as well as previously reported pediatric thrombectomy cases were defined as non-routine thrombectomy. Seven non-routine thrombectomy procedures in six children were included in the study. The National Institutes of Health Stroke Scale scores on admission ranged from 4 to 35; no procedure-related mortality or major neurologic morbidity occurred. One child died of causes related to the initial severe heart failure and stroke; otherwise, all the children had a modified Rankin scale score of 0 to 1 at follow-up. Unique clinical and procedural features in our case series included presentation with acute stent occlusion (two children), bilateral simultaneous internal carotid artery occlusions associated with a unilateral tandem middle cerebral artery (MCA) occlusion (one child), MCA occlusion caused by thromboembolism of the atrial myxoma (one child), and very distal (one child) or delayed thrombectomy (two children). Modifications to the standard medical and interventional algorithms may be required for mechanical thrombectomy in children. Referral centers specialized in pediatric neurology, pediatric anesthesia, and pediatric intervention are optimal for treating children using mechanical thrombectomy and for modifying the treatment, if required.

Rescue Therapy for Failed Mechanical Thrombectomy in Acute Ischemic Stroke: A Pooled Analysis of the Society of Vascular and Interventional Neurology Registry.

We aimed to evaluate the association between rescue therapy (RT) and functional outcomes compared to medical management (MM) in patients presenting after failed mechanical thrombectomy (MT). This cross-sectional study utilized prospectively collected and maintained data from the Society of Vascular and Interventional Neurology Registry, spanning from 2011 to 2021. The cohort comprised patients with large vessel occlusions (LVOs) with failed MT. The primary outcome was the shift in the degree of disability, as gauged by the modified Rankin Scale (mRS) at 90 days. Additional outcomes included functional independence (90-day mRS score of 0-2), symptomatic intracranial hemorrhage (sICH), and 90-day mortality. Of a total of 7,018 patients, 958 presented failed MT and were included in the analysis. The RT group comprised 407 (42.4%) patients, and the MM group consisted of 551 (57.5%) patients. After adjusting for confounders, the RT group showed a favorable shift in the overall 90-day mRS distribution (adjusted common odds ratio = 1.79, 95% confidence interval [CI] = 1.32-2.45, p < 0.001) and higher rates of functional independence (RT: 28.8% vs MM: 15.7%, adjusted odds ratio [aOR] = 1.93, 95% CI = 1.21-3.07, p = 0.005) compared to the MM group. RT also showed lower rates of sICH (RT: 3.8% vs MM: 9.1%, aOR = 0.52, 95% CI = 0.28-0.97, p = 0.039) and 90-day mortality (RT: 33.4% vs MM: 45.5%, aOR = 0.61, 95% CI = 0.42-0.89, p = 0.009). Our findings advocate for the utilization of RT as a potential treatment strategy for cases of LVO resistant to first-line MT techniques. Prospective studies are warranted to validate these observations and optimize the endovascular approach for failed MT patients. ANN NEUROL 2024;96:343-355.

Efficacy and Safety of a New Delivery Assist Catheter with a Flexible, Spindle-Shaped Shaft in Mechanical Thrombectomy

Large-bore aspiration catheters (ACs) are used successfully in mechanical thrombectomy (MT). However, tortuous access routes prevent device navigation because of the ledge effect. The AXS Offset Delivery Assist Catheter is designed to reduce the ledge effect. The purpose of this study was to evaluate whether the Offset affects AC navigation compared with standard inner microcatheters in MT. We retrospectively investigated 75MTs for anterior circulation occlusion between January 2018 and May 2022 at our hospital. All MTs were performed using an AC, and 2 types of inner microcatheter (Offset or 0.021-0.027-inch standard microcatheter) were chosen randomly during AC navigation. The patients' characteristics, MT techniques, angiographic findings, and clinical outcomes were compared between the Offset and standard group (Non-Offset). The puncture to first pass of the lesion time was investigated to compare the characteristics of the inner catheters. The Offset group comprised 12 patients versus 63 in the Non-Offset group. Although most baseline clinical characteristics and outcomes were similar between the groups, the puncture to first pass of the lesion time was significantly shorter in the Offset versus Non-Offset group (31±10 vs. 46±24minutes, respectively; P=0.032). In the Offset group, all stent retrievers were deployed via the Offset. One artery dissection and 8 symptomatic intracranial hemorrhages occurred in the Non-Offset group; no complications occurred in the Offset group. The AXS Offset delivery assist catheter permitted faster and safer navigation of various ACs to the occlusions compared with standard delivery microcatheters in MT.

The short-term outcome of intracranial stenosis with distal thrombosis treated with balloon-assisted tracking.

Treating intracranial stenosis with distal thrombosis (IS&DT) using traditional mechanical thrombectomy (MT) techniques has proven challenging. This study aimed to summarize the experience of utilizing the balloon-assisted tracking (BAT) technique for IS&DT. Demographic and morphologic characteristics of patients with IS&DT were collected for this study. The BAT technique, involving a half-deflated balloon outside the intermediate catheter tip, was used in all patients to navigate through the proximal stenosis. Various parameters were recorded, including the sequence of vascular reperfusion, the puncture-to-reperfusion time (PRT), the residual stenosis rate, and the occurrence of re-occlusion. The thrombolysis in cerebral infarction (TICI) scale was used to assess the reperfusion of intracranial vessels, with a TICI score of ≥2b considered as successful perfusion. The clinical status of patients was evaluated at three time points: pre-procedure, post-procedure, and at discharge using the modified Rankin score (mRS). In this study, a total of 10 patients were diagnosed with IS&DT, consisting of 9 male patients (90.0%) and 1 female patient (10.0%). The patients' mean age was 63.10 years (ranging from 29 to 79 years). The mean National Institute of Health Stroke Scale (NIHSS) score before treatment was 24.3 (ranging from 12 to 40), indicating the severity of their condition. Following the procedure, all patients achieved successful reperfusion with a thrombolysis in cerebral infarction (TICI) score of ≥2b. The average puncture-to-reperfusion time (PRT) was 51.8 min (ranging from 25 to 100 min), indicating the time taken for the procedure. During the perioperative period, three patients (30.0%) experienced complications. One patient had hemorrhage, while two patients had contrast extravasation. Among these cases, only the patient with hemorrhage (10%) suffered from a permanent neurological function deficit. At discharge, the patient's condition showed improvement. The mean NIHSS score decreased to 13.2 (ranging from 1 to 34), indicating a positive response to treatment. The mean mRS score at discharge was 3.2 (ranging from 1 to 5), showing some level of functional improvement. In conclusion, the use of the balloon-assisted tracking (BAT) technique for treating intracranial stenosis with distal thrombosis (IS&DT) showed promising results. However, a moderate rate of perioperative complications was observed, warranting further investigation and refinement of the procedure.

Abstract WP192: Impact of Second Line Thrombectomy Technique Following Failed First Pass Thrombectomy for Anterior Circulation Stroke: To Switch or Not to Switch?

Introduction: Despite comparable outcomes for different frontline techniques in mechanical thrombectomy (MT) for acute ischemic stroke (AIS), there are sparse data regarding if and when to switch techniques if the first pass is unsuccessful. We aimed to investigate the impact of converting from one MT technique to another on the second MT attempt for AIS among patients with large vessel occlusion (LVO). Methods: This was a retrospective observational study using data from the large multicenter international Stroke Thrombectomy and Aneurysm Registry (STAR). Data from 29 stroke centers for 10,229 AIS patients treated with MT for LVO between January 2010 and December 2022 was investigated. The primary outcome measure was successful recanalization defined as modified Thrombolysis in Cerebral Ischemia (mTICI) score of 2b or higher. 90-day modified Rankin score (mRS) 0-2, mortality and symptomatic hemorrhage were used as secondary outcomes. Clinical and technical outcomes after the second MT attempt were compared between those with or without technique conversion. Results: Among 10,229 AIS patients, 1,797 AIS patients with LVO failed first pass recanalization and were included in this retrospective analysis. 927 patients were female (52%) and median (interquartile range) age was 72 (61-81) years. Converting to alternative techniques following a first failed attempt was more likely to be associated with successful recanalization at the second attempt (adjusted odds ratio 2.30, 95% CI: 1.37-3.86, P = 0.002) and 90-day good clinical outcome (adjusted odds ratio 2.10, 95% CI: 1.15-3.85, P = 0.02) after multivariate adjustment. Conclusions: This study demonstrates better clinical and technical outcomes with conversion of MT technique for the second attempt in AIS patients with LVO who failed first pass recanalization.

Abstract WMP96: When to Change? Altering Strategies in Mechanical Thrombectomy May Impact Reperfusion Rates

Introduction: Earlier and greater reperfusion in mechanical thrombectomy (MT) leads to better clinical outcomes. The timing and potential benefit of switching thrombectomy techniques after failed device passes remains unclear. Methods: Retrospective analysis of a prospective comprehensive stroke center database including patients with intracranial ICA, MCA M1/M2, or Basilar occlusions undergoing MT with either Stent-Retriever (SR), Contact Aspiration (CA) or Combined technique (CT) from 2015 to 2023. Our primary endpoint was complete/near-complete reperfusion (eTICI 2c-3) at pass #2 (after pass #1 failure). Secondary endpoints included 1) eTICI2b-3 at pass#2, and 2) eTICI2c-3 with pass #3 (following failure in two consecutive passes with the same technique). We used logistic or Firth regression to compare reperfusion rates and Kaplan-Meier analysis for cumulative rates. Results: Among 3130 MTs in the study period, 1810 met inclusion criteria. Median age [IQR] was 65 [55 - 76] years and 51.5% were male. Following a failed first pass, switching from CA to either CT or SR was associated with higher eTICI 2c-3 (aOR [95%CI] 2.8 [1.3 - 6.5] and 7.4 [1.4-54.8], respectively). Changing from CT or SR to any other technique was not associated with higher reperfusion. Secondary endpoint analysis for eTICI2b-3 yielded comparable results. For the third pass, switching to CT after two repeated failed SR or two repeated failed CA attempts was associated with higher eTICI 2c-3 as compared to repeating the original strategy (SR aOR 5.8 [1.4 - 33.3]; AC aOR 5.6 [1.1 - 41.2]). We did not observe benefit in switching to alternative technique following one or two consecutive passes with CT. After three repeated attempts with the same technique, CT led to greater eTICI 2c-3 as compared to SR and CA (83% vs. 72% vs. 64%, p &lt; 0.001). Conclusions: While limited by small subgroup sample sizes, our study strengthens the hypothesis that early changes in MT technique may have an impact on reperfusion. Our data indicates that if CA fails on first pass, transition to SR or CT should be considered. After two failed consecutive SR or CA passes, transition to CT should be contemplated.

Common design and data elements reported in active mechanical thrombectomy trials focusing on distal medium vessel occlusions and minor strokes: a systematic review

BackgroundDistal medium vessel occlusions (DMVOs) and minor strokes represent emerging frontiers in mechanical thrombectomy (MT). Although several randomized clinical trials (RCTs) are underway, the design characteristics of these trials and...

Technique and impact on first pass effect primary results of the ASSIST global registry

BackgroundPatients treated with mechanical thrombectomy (MT) for acute ischemic strokes from large vessel occlusion (LVO) have better outcomes with effective reperfusion. However, it is unknown which technique leads to better...

Comparative analysis of syringes versus pump devices in benchtop aspiration thrombectomy models: A systematic review and meta-analysis.

Although direct contact aspiration has emerged as one of the leading techniques for mechanical thrombectomy (MT), there is still ongoing debate about the aspiration/suction pump devices that can optimize recanalization rates. To address this gap, we conducted a meta-analysis comparing the aspiration efficacy of 60 ml syringe and pump devices in benchtop MT models. Systematic literature review was conducted using Medline, Embase, Web of Science, and Scopus in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Outcomes of interest included flow rate and vacuum pressure delivered by a 60 ml syringe and several aspiration pumps. We used a random effects model to calculate the mean difference (MD) with 95% confidence intervals (CIs) and a statistically significant difference was considered as a two-sided p-value of less than 0.05. We included six benchtop studies comparing 60 ml syringes and vacuum pumps. Our meta-analysis showed that there were no significant differences in vacuum pressure (MD:0.71inHg, 95% CI: [-0.81;2.23], p = 0.359) and flow rate (MD:0.27 mL/s, 95% CI: [-3,07; 3.61], p = 0.873) between 60 ml syringes and vacuum pumps groups. Our study demonstrated comparable performance in terms of vacuum pressure and flow rates between a 60 ml syringe and a heterogeneous combination of commercially available aspiration pumps.

Abstract 236: Effects of intravenous thrombolysis on thrombectomy outcomes: a systematic review and meta‐analysis

Introduction Efficacy and safety of intravenous thrombolysis (IVT) in patients undergoing mechanical thrombectomy (MT) is still debatable. However, IVT's efficacy on stent retriever (SR) and aspiration thrombectomy (ASP) outcomes specifically remain unclear. In our meta‐analysis, we aimed to explore the effects of IVT on SR and ASP thrombectomy outcomes. Methods A systematic literature review was steered using Medline, Embase, Scopus, Web of Science, and Cochrane Center of Clinical Trials databases, according to PRISMA guidelines. Outcomes of interest included successful recanalization (modified Thrombolysis In Cerebral Infarction (mTICI) ≥2b), functional independence (modified Rankin Scale (mRS) ≤2), modified first pass efficacy (mFPE), symptomatic intracranial hemorrhage (sICH), and embolization to new territories (ENT). Results We included four randomized controlled trials with 1176 patients. SR and ASP had similar mTICI ≥2b, mFPE, and mRS 0‐2 rates whether they received IVT or not. SR without IVT was associated with a lower rate of mFPE compared with the SR+IVT (RR 0.85, 95% CI 0.74 to 0.97). Additionally, ASP without IVT resulted in a lower rate of mRS 0‐2 than the ASP+IVT (RR 0.78, 95% CI 0.60 to 1.01). Finally, bridging therapy did not increase sICH and ENT rates after ASP or SR thrombectomy. Conclusion Our analysis suggests that SR and ASP thrombectomy have equivalent efficacy and safety outcomes regardless of prior IVT administration. Moreover, our results indicate that administration of IVT before MT may improve certain outcomes based on the used first‐line MT technique.

The effect of occlusion location and technique in mechanical thrombectomy for minor stroke.

Endovascular mechanical thrombectomy (MT) is an established treatment for large vessel occlusion strokes with a National Institutes of Health Stroke Scale (NIHSS) score of 6 or higher. Data pertaining to minor strokes, medium, or distal vessel occlusions, and most effective MT technique is limited and controversial. A multicenter retrospective study of all patients treated with MT presenting with NIHSS score of 5 or less at 29 comprehensive stroke centers. The cohort was dichotomized based on location of occlusion (proximal vs. distal) and divided based on MT technique (direct aspiration first-pass technique [ADAPT], stent retriever [SR], and primary combined [PC]). Outcomes at discharge and 90 days were compared between proximal and distal occlusion groups, and across MT techniques. The cohort included 759 patients, 34% presented with distal occlusion. Distal occlusions were more likely to present with atrial fibrillation (p = 0.008) and receive IV tPA (p = 0.001). Clinical outcomes at discharge and 90 days were comparable between proximal and distal groups. Compared to SR, patients managed with ADAPT were more likely to have a modified Rankin Scale of 0-2 at discharge and at 90 days (p = 0.024 and p = 0.013). Primary combined compared to ADAPT, prior stroke, multiple passes, older age, and longer procedure time were independently associated with worse clinical outcome, while successful recanalization was positively associated with good clinical outcomes. Proximal and distal occlusions with low NIHSS have comparable outcomes and safety profiles. While all MT techniques have a similar safety profile, ADAPT was associated with better clinical outcomes at discharge and 90 days.

Benchtop evaluation of a double stent retriever thrombectomy technique for acute ischemic stroke treatment.

A mechanical thrombectomy technique using a double stent retriever approach has been reported for the treatment of patients with acute ischemic stroke. The purpose of this study was to perform a benchtop evaluation of the mechanism of action and efficacy of a double-stent retriever approach compared to a single-stent retriever approach. In vitro, mechanical thrombectomy procedures were performed in a vascular phantom reproducing an M1-M2 occlusion with two different clot analog consistencies (soft and hard). We compared the double stent retriever approach to the single stent retriever approach and recorded the recanalization rate, distal embolization, and retrieval forces of each mechanical thrombectomy procedure. The double stent retriever approach achieved a higher recanalization rate and lower embolic complications compared to the single stent retriever approach. This seems to stem from two facts: the greater probability of targeting the correct artery with two stents in the case of bifurcation occlusion, and an improved clot capture mechanism using the double stent retriever approach. However, the double stent retriever was associated with an increased initial retrieval force. In vitro evaluation of the mechanism of action of the double stent retriever provided explanations that appear to support the high efficacy of such an approach in patient cohorts and could help operators when selecting the optimal mechanical thrombectomy strategy in cases of arterial occlusions difficult to treat with a single stent retriever.

Effects of intravenous thrombolysis on stent retriever and aspiration thrombectomy outcomes: a systematic review and meta-analysis of the randomized controlled trials

BackgroundRisks and benefits of intravenous thrombolysis (IVT) in patients undergoing mechanical thrombectomy (MT) have been a topic of interest. However, IVT’s specific effects on stent retriever (SR) and aspiration thrombectomy...

NIMBUS geometric clot extractor for challenging clots: Real-world clinical experience and clot composition.

Revascularization rates following mechanical thrombectomy (MT) for acute ischemic stroke (AIS) remain suboptimal for patients with fibrin-rich, recalcitrant clots. The NIMBUS Geometric Clot Extractor has demonstrated promising in vitro revascularization rates using fibrin-rich clot analogs. This study assessed the retrieval rate and composition of clot using NIMBUS in a clinical setting. This retrospective study included patients who underwent MT with NIMBUS at two high-volume stroke centers between December 2019 and May 2021. NIMBUS was used for clots deemed challenging to remove at the interventionalist's discretion. At one of the centers, per pass clot was collected for histological analysis by an independent lab. A total of 37 patients (mean age 76.87 ± 11.73 years; 18 female; mean time from stroke onset 11.70 ± 6.41 h) were included. NIMBUS was used as first and second-line device in 5 and 32 patients, respectively. The main reason for using NIMBUS (32/37) was the failure of standard MT techniques after a mean 2.86 ± 1.48 number of passes. Substantial reperfusion (mTICI ≥2b) was achieved in 29/37 patients (78.4%) with a mean of 1.81 ± 1.00 NIMBUS passes (mean 4.68 ± 1.68 passes with all devices), and NIMBUS was the final device used in 79.3% (23/29) of those cases. Clot specimens from 18 cases underwent composition analysis. Fibrin and platelets represented 31.4 ± 13.7% and 28.8 ± 18.8% of clot components; 34.4 ± 19.5% were red blood cells. In this series, NIMBUS was effective in removing tough clots rich in fibrin and platelets in challenging real-world situations.

Abstract Number ‐ 109: Mechanical Thrombectomy Hands‐on Skill Workshop for MT2020+ in the Caribbean

Introduction While mechanical thrombectomy (MT) is proven to be lifesaving and disability‐sparing, there remains disparities in access in low‐ to middle‐income countries (LTMICs), including the Caribbean. We hypothesized that team‐oriented MT workshops would improve MT skills and change practice patterns for MT services in this region. Methods We designed a 22‐hour MT workshop which was conducted as two identical events: in English (Jamaica, January 2022), and in Spanish (Dominican Republic, May 2022). The workshops included neurointerventional teams (practicing neurointerventionalists, neuroIR nurses and technicians), focused on patient selection, acutetreatment and post‐MT care of patients with stroke due to large vessel occlusion. MT skills, procedure duration and potential harmful techniques were recorded before and after by independent evaluators utilizing flow models under fluoroscopy. Overall course evaluation was performed. Press conferences were included to raise stroke awareness and emphasize the importance of early stroke presentation. Results Twenty‐two physicians and their teams from eight countries across the Caribbean completed the didactic and hands‐on training. Eighteen groups completed both pre‐ and post‐MT hands‐on testing and were included in the final analysis. Pre‐ and post‐course hands‐on assessment showed that the course effectively reduced the total time to complete a simulated MT procedure from 36.5 to 21.1 min (Figure 1; p&lt; 1.0×10‐7). All groups showed an improvement in measures of good MT techniques, which resulted in a 39% improvement in complete reperfusion (8/18 groups achieved a TICI 3 score on pre‐course vs. 15/18 groups on post‐course). There was a significant reduction in total potentially dangerous maneuvers by 82% (p&lt; 0.002), with 12/18 groups performing an average 2 dangerous maneuvers on pre‐course simulation vs. only 4/18 groups performing an average 1 dangerous maneuver after completing the course. Participants also demonstrated increased knowledge of stroke treatment and stroke system of care. Utilizing a basic stroke knowledge questionnaire, we found 28% respondents did not have a baseline passing grade vs 100% passed after the workshop. The average post‐workshop knowledge score was 80%. Universally the workshop was rated as very satisfactory and likely to change practice in 93% of the Dominican Republic participants and 75% among Jamaican participants. Conclusions A team‐based approach to MT training is novel, effective in reducing time to reperfusion and harmful techniques, and improves competencies. Team members independently demonstrated advanced stroke learning post‐training. To our knowledge, this is the first workshop of its kind; it is feasible, practice‐changing and creates a pathway for increasing access to MT in LTMICs.

Abstract Number ‐ 23: In vitro evaluation of thrombectomy techniques: What is the most efficient combined technique?

Introduction A combined technique with contact aspiration and stent retriever is widely used for the treatment of patients with acute ischemic stroke due to the potential synergistic effect of the two technologies. However, there are no large studies that conclude the combined technique is more efficient compared to stent retriever only or contact aspiration. One of the issues in combined techniques may be the complexity, and multiple variations of combined techniques exist. We performed an in vitro study using three‐dimensional (3D) flow models and performed clot retrieval in order to explore effective and safe techniques for mechanical thrombectomy. Methods In a 3D silicone flow model with moderate tortuosity, we compared several techniques: 1. a pinching combination method (pull out stent retriever and aspiration catheter as a unit) with several variations of aspiration catheter locations; 2. an ingestion combination method (stent retriever removal through aspiration catheter); 3. stent retriever only; and 4. contact aspiration. We evaluated the success retrieval rates of a thrombus in the M2 branch. In addition, we measured pulling force during each technique to determine the amount of force exerted on the distal MCA vessel. Results The highest clot retrieval rate was achieved with a pinching combination technique with close contact with an aspiration catheter. The pulling force on the distal MCA vessel was high with the techniques that had high clot retrieval rates and low with the techniques that had low success rates. The pulling force was higher when the stent retriever was fully deployed compared with a pinching technique with a stent partially covered with an aspiration catheter. Conclusions In our in vitro model, the pinching combination method showed the highest clot retrieval rate when the aspiration catheter was advanced to the clot and the stent retriever. The pulling force experiments suggested the shorter stent retriever may decrease the rate of subarachnoid hemorrhage due to low pulling force.

Abstract Number ‐ 164: Clot Density as a Predictor for Successful Mechanical Thrombectomy

Introduction Switching mechanical thrombectomy techniques (ADAPT, SR or combination) mid procedure has the potential to prolong time to recanalization as well as increase associated healthcare costs. The basis of selecting the frontline technique still relies heavily on the operators’ preference. Conflicting results indicating the varying performance of techniques relative to clot composition have been reported. Clot composition can be estimated based on clot density calculated in Hounsfield Units (HU) on pre‐intervention CT. Identifying how various clot composites behave can aid in the decision making for selecting a frontline technique.Our objective is to determine if clot density as measured by Hounsfield units can predict successful recanalization with ADAPT and the need for rescue stentriever when using ADAPT as the first line technique. Methods Retrospective review of all patients undergoing mechanical thrombectomy with first pass ADAPT at a single urban tertiary care academic stroke center. Clot HU values were calculated on pre‐intervention scans. We evaluated the number of passes, the use of rescue SR, the post intervention TICI grade and mRS on final follow up. Results There were 167 patients that underwent MT with ADAPT as the frontline approach. 122 were excluded for inability to calculate HU on pre‐ intervention scans, most often due to contamination with contrast media. 45 patients were included in the final analysis. 18/45 (40%) required SR rescue due to incomplete recanalization with first pass ADAPT. HU were dichotomized around the mean to “high” and “low”. Higher HU value was associated higher likelihood of SR use and higher final mRS scores, these however did not reach statistical significance. There was no difference in the total number of passes or the final TICI grade. AUC and ROC did not show a correlation between HU value and the use of SR or a higher number of passes need to achieve TICI ≥ 2b recanalization. Conclusions In our patient cohort, HU value was not able to predetermine the success rate of MT using ADAPT. There was no correlation between HU value and functional outcomes of patients. Reliability of clot HU value in determining MT success with ADAPT could not be established. Other factors should be considered when selecting frontline technique in mechanical thrombectomy.

Comparison of a direct aspiration first pass technique vs. stent retriever thrombectomy for the treatment of acute large vessel occlusion stroke in the anterior circulation with atrial fibrillation.

The stent retriever thrombectomy (SRT) and a direct aspiration first-pass technique (ADAPT) are the two main mechanical thrombectomy (MT) techniques for acute ischemic stroke. Few data are available for comparing the therapeutic effects associated with the two mechanical thrombectomy techniques in acute ischemic stroke with atrial fibrillation. The purpose of this study was to compare the efficacy and safety of both techniques for the treatment of acute large vessel occlusion stroke in the anterior circulation with atrial fibrillation. Retrospective analysis was performed in stroke patients with atrial fibrillation admitted to Guangzhou Red Cross Hospital from January 2018 to June 2022 who received mechanical thrombectomy by either SRT or ADAPT. Comparisons were made with regards to the initial traits, course of therapy, effectiveness indicators, and complications of these individuals. The primary outcome is recanalization rate. In this study, after screening 431 patients, 92 eligible patients, with 48 patients received SRT and 44 patients received ADAPT, were included. There was no significant difference in the recanalization rate between the two groups (SRT 87.5% vs. ADAPT 84.1%, P = 0.639). Compared with SRT, patients in ADAPT group had a shorter puncture to recanalization time [33.5 min (27.0-59.5) vs. 50.5 min (31.5-91.5), P = 0.009], a higher first pass success recanalization rate (54.5 vs. 33.3%, p = 0.040), and a higher rate of patients with improvement of NIHSS scores ≥4 at discharge (84.1 vs. 56.3%, P = 0.004). However, distal embolization occurred more frequently in the ADAPT group than that in SRT group (50.0 vs. 22.9%, P = 0.007). There was no significant difference between the two groups in the 3-month mRS score, symptomatic cerebral hemorrhage, or mortality. Compared with SRT, ADAPT has similar recanalization rate for the treatment of acute large vessel occlusion stroke in the anterior circulation with atrial fibrillation. However, ADAPT might be more effective in terms of shorter puncture to recanalization time and higher first pass success recanalization rate. Further studies are needed for confirming our results.