REACT Aspiration Catheters: Clinical Experience and Technical Considerations

Reymond P., Brina O., Girdhar G., Bolanos O., Lovblad K., Machi P.

Mechanical thrombectomy using an aspiration catheter (AC) is widely performed in patients with acute ischemic stroke due to large vessel occlusion. AC diameter directly impacts aspiration performance, which has led device companies to develop large bore ACs. The purpose of this study was to evaluate the in vitro performance of several commercially available large bore ACs.We conceived an experimental set up to assess tracking force, aspiration flow rate, and distal end tensile force pre- and post-thrombectomy of ACs including Sofia 6 (Microvention Inc., California, USA), React 71 (Medtronic Neurovascular, Irvine, California, USA), Jet 7 (Penumbra Inc, Alameda, California, USA), Catalyst 7 (Stryker Neurovascular, Kalamazoo, Michigan, USA) and Embovac 071 (Johnson & Johnson Medical Ltd, UK).React 71 and Sofia 6 had significantly lower trackability force compared to the other ACs tested. Distal AC segment tensile force was highest for React 71 and lowest for Jet 7. Jet 7 had the highest internal diameter and the highest aspiration flow rate.The data from this comparative analysis may assist clinicians in selecting the appropriate AC and highlights the need for key performance criteria during the development of next-generation large-bore ACs for optimal AC performance.

Requena M., Piñana C., Olive-Gadea M., Hernández D., Boned S., De Dios M., Rodrigo M., Rivera E., Muchada M., Cuevas J.L., Rubiera M., García-Tornel Á., Gramegna L.L., Molina C., Ribo M., et. al.

Introduction Mechanical thrombectomy (MT) with combined treatment including both a stent retriever and distal aspiration catheter may improve recanalization rates in patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO). Here, we evaluated the effectiveness and safety of the REACT aspiration catheter used with a stent retriever. Methods This prospective study included consecutive adult patients who underwent MT with a combined technique using REACT 68 and/or 71 between June 2020 and July 2021. The primary endpoints were final and first pass mTICI 2b-3 and mTICI 2c-3 recanalization. Analysis was performed after first pass and after each attempt. Secondary safety outcomes included procedural complications, symptomatic intracranial hemorrhage (sICH) at 24 h, in-hospital mortality, and 90-day functional independence (modified Rankin Scale [mRS] 0–2). Results A total of 102 patients were included (median age 78; IQR: 73–87; 50.0% female). At baseline, median NIHSS score was 19 (IQR: 11–21), and ASPECTS was 9 (IQR: 8–10). Final mTICI 2b-3 recanalization was achieved in 91 (89.2%) patients and mTICI 2c-3 was achieved in 66 (64.7%). At first pass, mTICI 2b-3 was achieved in 55 (53.9%) patients, and mTICI 2c-3 in 37 (36.3%). The rate of procedural complications was 3.9% (4/102), sICH was 6.8% (7/102), in-hospital mortality was 12.7% (13/102), and 90-day functional independence was 35.6% (36/102). Conclusion A combined MT technique using a stent retriever and REACT catheter resulted in a high rate of successful recanalization and first pass recanalization in a sample of consecutive patients with AIS due to LVO in clinical use.

Li J., Tomasello A., Requena M., Canals P., Tiberi R., Galve I., Engel E., Kallmes D.F., Castaño O., Ribo M.

BackgroundIn mechanical thrombectomy (MT), distal access catheters (DACs) are tracked through the vascular anatomy to reach the occlusion site. The inability of DACs to reach the occlusion site has been reported as a predictor of unsuccessful recanalization. This study aims to provide insight into how to navigate devices through the vascular anatomy with minimal track forces, since higher forces may imply more risk of vascular injuries.MethodsWe designed an experimental setup to monitor DAC track forces when navigating through an in vitro anatomical model. Experiments were recorded to study mechanical behaviors such as tension buildup against vessel walls, DAC buckling, and abrupt advancements. A multiple regression analysis was performed to predict track forces from the catheters’ design specifications.ResultsDACs were successfully delivered to the target M1 in 60 of 63 in vitro experiments (95.2%). Compared to navigation with unsupported DAC, the concomitant coaxial use of a microcatheter/microguidewire and microcatheter/stent retriever anchoring significantly reduced the track forces by about 63% and 77%, respectively (p<0.01). The presence of the braid pattern in the reinforcement significantly reduced the track forces regardless of the technique used (p<0.05). Combined coil and braid reinforcement configuration, as compared with coil alone, and a thinner distal wall were predictors of lower track force when navigating with unsupported DAC.ConclusionsThe use of microcatheter and stent retriever facilitate smooth navigation of DACs through the vascular tortuosity to reach the occlusion site, which in turn improves the reliability of tracking when positioning the DAC closer to the thrombus interface.

Liu Y., Gebrezgiabhier D., Zheng Y., Shih A.J., Chaudhary N., Pandey A.S., Larco J.L., Madhani S.I., Abbasi M., Shahid A.H., Quinton R.A., Kadirvel R., Brinjikji W., Kallmes D.F., Savastano L.E.

Baek S.H., Kim S., Kang M., Choi J., Kwon H.J., Kim D.W.

Purpose Mechanical thrombectomy using the stent-retriever in conjunction with the distal access catheter may improve the rates of successful revascularization and clinical outcomes in patients with acute stroke. We aimed to compare two different thrombectomy techniques, according to the position of the distal access catheter tip in the combined stent-retriever and aspiration approach. Methods In this retrospective study, patients with middle cerebral artery occlusion treated with the combined technique were divided into two groups based on the tip position of the distal access catheter: distal group (catheter placed adjacent to the thrombus) and proximal group (catheter placed in the cavernous segment of the internal carotid artery below the ophthalmic artery). Baseline characteristics, angiographic results, and clinical outcomes were compared. Results Eighty-three patients (distal group, n = 45; proximal group, n = 38) were included. Higher complete reperfusion was observed in the distal group (unweighted analysis: 66.7% vs. 42.1%, p = 0.025; weighted analysis: 74.0% vs. 28.8%; p = 0.002). In the multivariate analysis, the distal tip position was independently associated with complete reperfusion (unweighted analysis: aOR, 4.10; 95% CI, 1.40–11.98; p = 0.01; weighted analysis: aOR, 5.20; 95% CI, 1.72–15.78; p = 0.004). The distal group also showed more favorable clinical outcomes and early neurological improvement (unweighted analysis: 62.2% vs. 55.3%; p = 0.521, 60% vs. 50%; p = 0.361, respectively; weighted analysis: 62.7% vs. 61.1%; p = 0.877, 66% vs. 45.7%; p = 0.062, respectively). However, more arterial dissections were observed in the distal group (8.9%, n = 4 vs. 2.6%, n = 1; p = 0.36). In the distal group, one patient with vascular injury died due to complications. No cases of emboli in new territory were observed. Conclusions Distal tip position of the distal access catheter has a significant impact on reperfusion in patients with acute ischemic stroke. However, there was also a higher rate of vascular injury as the catheter was advanced further. If advancement to the target lesion is too difficult, placing it in the cavernous internal carotid artery may be a viable method without complications.

Kalousek V., Yoo A.J., Sheth S.A., Janardhan V., Mamic J., Janardhan V.

Complete reperfusion (TICI 3) after the first thrombectomy attempt or first pass effect (FPE) is associated with best clinical outcomes in large-vessel occlusion (LVO) acute ischemic stroke. While endovascular therapy techniques have improved substantially, FPE remains low (24-30%), and new methods to improve reperfusion efficiency are needed.In a prospective observational cohort study, 40 consecutive patients underwent cyclical aspiration thrombectomy using CLEARTM Aspiration System (Insera Therapeutics Inc., Dallas, TX). Primary outcome included FPE with complete/near-complete reperfusion (TICI 2c/3 FPE). Secondary outcomes included early neurological improvement measured by the National Institute of Health Stroke Scale (NIHSS), safety outcomes, and functional outcomes using modified Rankin Scale (mRS). Outcomes were compared against published historical controls.Among 38 patients who met criteria for LVO, median age was 75 (range 31-96). FPE was high (TICI 3: 26/38 [68%], TICI 2c/3: 29/38 [76%]). Among anterior circulation strokes, core lab-adjudicated FPE remained high (TICI 3: 17/29 [59%], TICI 2c/3: 20/29 [69%]), with excellent final successful revascularization results (Final TICI 3: 24/29 [83%], Final TICI 2c/3: 27/29 [93%]). FPE in the CLEAR-1 cohort was significantly higher compared to FPE using existing devices (meta-analysis) from historical controls (TICI 2c/3: 76% vs. 28%, p = 0.0001). High rates of early neurological improvement were observed (delta NIHSS≥4: 35/38 [92.1%]; delta NIHSS≥10: 27/38 [71%]). Similarly, high rates of good functional outcomes (mRS 0-2: 32/38 [84%]) and low mortality (2/38 [5%]) were observed.Cyclical aspiration using the CLEARTM Aspiration System is safe, effective, and achieved a high TICI 3 FPE for large-vessel strokes.

Li J., Castaño O., Tomasello A., de Dios Lascuevas M., Canals P., Engel E., Ribo M.

BackgroundA direct aspiration first pass thrombectomy (ADAPT) is a fast-growing technique for which a broad catalog of catheters that provide a wide range of aspiration forces can be used. We aimed to characterize different catheters' aspiration performance on stiff clots in an in vitro vascular model. We hypothesized that labeled catheter inner diameter (labeled-ID) is not the only parameter that affects the aspiration force (asp-F) and that thrombus–catheter tip interaction and distensibility also play a major role.MethodsWe designed an experimental setup consisting of a 3D-printed carotid artery immersed in a water deposit. We measured asp-F and distensibility of catheter tips when performing ADAPT on a stiff clot analog larger than catheter labeled-ID. Correlations between asp-F, catheter ID, and tip distensibility were statistically assessed.ResultsExperimental asp-F and catheter labeled-ID were correlated (r=0.9601; P<0.01). The relative difference between experimental and theoretical asp-F (obtained by the product of the tip’s section area by the vacuum pressure) correlated with tip’s distensibility (r=0.9050; P<0.01), evidencing that ADAPT performance is highly influenced by catheter tip shape-adaptability to the clot and that the effective ID (eff-ID) may differ from the labeled-ID specified by manufacturers. Eff-ID showed the highest correlation with experimental asp-F (r=0.9944; P<0.01), confirming that eff-ID rather than labeled-ID should be considered to better estimate the device efficiency.ConclusionsCatheter tip distensibility can induce a significant impact on ADAPT performance when retrieving a stiff clot larger than the device ID. Our findings might contribute to optimizing thrombectomy strategies and the design of novel aspiration catheters.

Nogueira R.G., Ryan D., Mullins L., Thornton J., Fitzgerald S.

BackgroundBalloon guide catheters (BGCs) achieve proximal flow control during thrombectomy but antegrade intracranial flow often persists via the Circle of Willis. Closely sizing an aspiration catheter to the target vessel might achieve greater flow control and improve technical performance. Our objective was to measure the impact of aspiration catheter size on distal flow control and flow reversal with and without the use of BGCs. Clot retrieval testing was performed to establish the impact of these parameters on revascularization.MethodsAn in vitro thrombectomy model replicated in vivo conditions. Flow was measured continuously using ultrasonic flow sensors placed 20 cm distal to the catheter tip in the middlel cerebral artery (MCA). Four aspiration catheters of increasing size were evaluated: ACE 60 and 64 (Penumbra), SOFIA Plus (MicroVention), and Millipede 088 (Perfuze). Two clot analog types (red blood cell-rich and fibrin/platelet-rich) were used for clot retrieval testing.ResultsThe larger area of the ‘superbore’ Millipede 088 catheter resulted in a larger reduction in antegrade flow than standard aspiration catheters, even when the latter were combined with a BGC. During aspiration, 6Fr catheters were unable to cause flow reversal in the distal MCA while the Millipede 088 achieved significant distal flow reversal (−146 mL/min) (P<0.0001*) (*denotes significance). The solo use of Millipede 088 resulted in better recanalization outcomes and significantly reduced distal emboli for internal carotid artery (P=0.015*) and MCA (P=0.014*) occlusions compared with all other devices and combinations.ConclusionsMaximizing the catheter-to-vessel size facilitates near flow-arrest on catheter insertion, potentially negating the need for a BGC. A 0.088 inch aspiration catheter enables significant flow reversal in the distal MCA during aspiration.

Fernandez-Sanchez D., Garcia-Sabido D., Jovin T.G., Villanova H., Andersson T., Nogueira R.G., Cognard C., Ribo M., Siddiqui A.H., Galve I., Arad O., Salmon F.

BackgroundANA Advanced Neurovascular Access provides a novel funnel component designed to reduce clot fragmentation and facilitate retrieval in combination with stent-retrievers (SRs) in stroke patients by restricting flow and limiting clot shaving. In previous publications ANA presented excellent in vitro/in vivo efficacy data, especially with fibrin-rich hard clots. We aimed to determine the main physical property responsible for these results, namely suction force versus aspiration flow.MethodsWe evaluated in a bench model the suction force and flow generated by ANA and compared them to other neurovascular catheters combined with a SR (Solitaire). Aspiration flow was evaluated with a flow rate sensor while applying vacuum pressure with a pump. Suction force was determined using a tensile strength testing machine and a purposely designed tool that completely seals the device tip simulating complete occlusion by a hard clot. Suction force was defined as the force needed to separate the device from the clot under aspiration. All experiments were repeated five times, and mean values used for comparisons.ResultsAspiration flow increased with the inner diameter of the device: ANA 1.85±0.04 mL/s, ACE68 3.74±0.05 mL/s, and 8F-Flowgate2 5.96±0.30 mL/s (P<0.001). After introducing the SR, the flow was reduced by an average of 0.57±0.12 mL/s. Due to its larger distal surface, ANA suction force (1.69±0.40 N) was significantly higher than ACE68 (0.26±0.04 N) and 8F-Flowgate2 (0.42±0.06 N) (P<0.001). After introducing the SR, suction force variation was not relevant except for ANA that increased to 2.64±0.41 N.ConclusionDespite lower in vitro aspiration flow, the ANA design showed a substantially higher suction force than other thrombectomy devices.

Frölich A.M., Kim W., Stribrny K., Jansen O., Möhlenbruch M., Szikora I., Wodarg F., Fiehler J., Otto K., Chou T., Buhk J.H., English J.

BackgroundIn large vessel occlusionstroke, navigation of aspiration catheters (AC) can be impeded by vessel tortuosity and the ophthalmic artery origin. A novel tapered delivery catheter was designed to facilitate delivery without disturbing the embolus. We assessed AC deliverability in vitro and validated the observations in a first-in-human experience.MethodsIn a vascular model with three challenging craniocervical scenarios, two commercial AC were advanced from the carotid to the middle cerebral artery by four neurointerventionalists. Catheter deliverability with standard microwire and microcatheter (MC) combinations and the Tenzing 7 (T7) Delivery Catheter (Route 92 Medical, San Mateo, CA) were compared. Operators rated aspects of catheter deliverability on a 5-point scale. Results were compared with device delivery patterns at a neurovascular center before and after clinical introduction of T7.ResultsIn vitro, success rate and speed were higher with T7 (96%; mean 30±10 s) than with MC (65%; 72±47 s, p<0.001 each), with fewer interactions with the occlusion site (T7: 54% vs MC: 77%, p=0.004). T7 received superior ratings regarding carotid artery deflection (T7: 2, IQR1-3 vs MC: 3, IQR2-3, p<0.001), guide catheter pushback (T7: 2, IQR1-3 vs MC: 3, IQR3-3, p<0.001) and ophthalmic artery passage (T7: 1.5, IQR1-2 vs MC: 4, IQR3-5, p<0.001). Before introduction of T7 at a single center, delivery of AC to a large vessel occlusion without crossing was achieved in 15/123 cases (12%). With T7, this rate was 28/31 patients (90.3%).ConclusionCompared with microcatheter and microwire combinations, T7 improves aspiration catheter delivery in vitro, minimizing the need to cross the occlusion. Initial clinical experience appears to validate the model’s observations.

Kyselyova A.A., Fiehler J., Leischner H., Flottmann F., Buhk J.H., Frölich A.M.

BackgroundA direct aspiration first pass technique (ADAPT) is an efficient, safe, cost-effective, and fast thrombectomy technique.ObjectiveTo evaluate anatomical and clot characteristics associated with success of the aspiration component as part of ADAPT.Methods106 cases of acute carotid-T, basilar, and middle cerebral artery occlusion undergoing endovascular treatment with ADAPT were retrospectively assessed for successful catheter-clot contact and successful primary aspiration, defined as a Thrombolysis in Cerebral Infarction score ≥2b after primary aspiration with 5F or 6F aspiration catheters. Patient age, National Institutes of Health Stroke Scale (NIHSS) score, time from symptom onset to groin puncture, time from groin puncture to revascularization, aortic arch type, access vessel tortuosity, vessel diameter at the proximal end of the thrombus, catheter-to-vessel ratio (CVR), clot density, length, and perviousness were determined.ResultsSuccessful clot contact with the aspiration catheter was achieved in 76 cases (72%); these patients were younger (67.7±15.2 vs 73.7±11.4 years; p=0.05) and had less tortuous access vessels (1 vs 2 reverse curves; p=0.004) than those in whom clot contact failed. Successful primary aspiration occurred in 36 of these cases (47%) and was associated with significantly smaller vessel diameter at the proximal thrombus end (2.5±0.7 mm vs 3.1±1.3 mm; p=0.01) and higher CVR (CVR outer diameter: 0.85±0.2 vs 0.68±0.2; p=0.01 and CVR inner diameter: 0.72±0.2 vs 0.58±0.2; p<0.001). No significant differences were seen in aortic arch type, radiographic clot features, and NIHSS score.ConclusionWith ADAPT, patient age and vessel tortuosity affect the ability to deliver the aspiration catheter and achieve clot contact, whereas vessel diameter and CVR at the aspiration site seem to affect the effectiveness of clot aspiration. Strategies aimed at improving catheter deliverability and increasing CVR may increase the efficacy of ADAPT.

Boisseau W., Escalard S., Fahed R., Lapergue B., Smajda S., Maier B., Desilles J.P., Delvoye F., Ciccio G., Redjem H., Hebert S., Ben Maacha M., Walker G., Gory B., Richard S., et. al.

Mechanical thrombectomy is now the standard of care for acute ischemic stroke patients with large vessel occlusions, and can be performed with several devices and techniques. One of these techniques, direct aspiration (DA), consists of navigating a large-bore catheter up to the face of the clot and initiating forceful suction. This comprehensive review has three objectives: (1) to describe the direct aspiration technique; (2) to present the available evidence regarding predictive factors of DA success and performance compared with other techniques; and (3) to discuss the forthcoming improvements in distal aspiration.

Raymond S.B., Nasir-Moin M., Koch M.J., Rabinov J.D., Leslie-Mazwi T., Patel A.B.

IntroductionWe describe our initial experience with the React 68 catheter (Medtronic, Dublin, Ireland), an FDA-approved catheter designed for aspiration in cases of emergent large vessel occlusion, as compared with the ACE 68 catheter (Penumbra, Alameda, CA).MethodsThis observational study followed consecutive patients treated with the React catheter over a seven-month period at a comprehensive stroke center. Use of the device was per discretion of the operator. Patient demographics, thrombectomy technique, reperfusion scoring, and disposition were assessed. Performance was compared with patients treated with the ACE 68 catheter over a comparable period.ResultsWe treated 47 patients using the React 68 catheter using either aspiration alone or a combination of aspiration and stent retriever technique. The catheter was used in a variety of circumstances including proximal and distal occlusions involving the anterior and posterior circulation. Modified TICI 2b-3 was achieved in 45 of the 47 patients. The React 68 was comparable to the ACE 68 by all performance measures.ConclusionThe React 68 catheter is a large-bore reperfusion catheter with trackability suitable for use in direct aspiration for recanalization of emergent large vessel occlusion.

Powers W.J., Rabinstein A.A., Ackerson T., Adeoye O.M., Bambakidis N.C., Becker K., Biller J., Brown M., Demaerschalk B.M., Hoh B., Jauch E.C., Kidwell C.S., Leslie-Mazwi T.M., Ovbiagele B., Scott P.A., et. al.

Background and Purpose- The purpose of these guidelines is to provide an up-to-date comprehensive set of recommendations in a single document for clinicians caring for adult patients with acute arterial ischemic stroke. The intended audiences are prehospital care providers, physicians, allied health professionals, and hospital administrators. These guidelines supersede the 2013 Acute Ischemic Stroke (AIS) Guidelines and are an update of the 2018 AIS Guidelines. Methods- Members of the writing group were appointed by the American Heart Association (AHA) Stroke Council's Scientific Statements Oversight Committee, representing various areas of medical expertise. Members were not allowed to participate in discussions or to vote on topics relevant to their relations with industry. An update of the 2013 AIS Guidelines was originally published in January 2018. This guideline was approved by the AHA Science Advisory and Coordinating Committee and the AHA Executive Committee. In April 2018, a revision to these guidelines, deleting some recommendations, was published online by the AHA. The writing group was asked review the original document and revise if appropriate. In June 2018, the writing group submitted a document with minor changes and with inclusion of important newly published randomized controlled trials with >100 participants and clinical outcomes at least 90 days after AIS. The document was sent to 14 peer reviewers. The writing group evaluated the peer reviewers' comments and revised when appropriate. The current final document was approved by all members of the writing group except when relationships with industry precluded members from voting and by the governing bodies of the AHA. These guidelines use the American College of Cardiology/AHA 2015 Class of Recommendations and Level of Evidence and the new AHA guidelines format. Results- These guidelines detail prehospital care, urgent and emergency evaluation and treatment with intravenous and intra-arterial therapies, and in-hospital management, including secondary prevention measures that are appropriately instituted within the first 2 weeks. The guidelines support the overarching concept of stroke systems of care in both the prehospital and hospital settings. Conclusions- These guidelines provide general recommendations based on the currently available evidence to guide clinicians caring for adult patients with acute arterial ischemic stroke. In many instances, however, only limited data exist demonstrating the urgent need for continued research on treatment of acute ischemic stroke.

Bernava G., Rosi A., Boto J., Brina O., Kulcsar Z., Czarnetzki C., Carrera E., Schaller K., Lovblad K., Machi P.

BackgroundDirect thromboaspiration has been reported as an effective mechanical treatment for acute ischemic stroke. We aimed to determine whether the angle of interaction between the aspiration catheter and the clot affects the success of clot removal in ischemic stroke patients with large vessel occlusion in the anterior and posterior circulation.MethodsAll patients treated at our institution by direct thromboaspiration as a firstline technique between January 2016 and December 2017 were enrolled in the study. We retrospectively reviewed baseline and procedural characteristics, the angle of interaction formed between the aspiration catheter and the clot, the modified Thrombolysis in Cerebral Infarction score, and the 3 month modified Rankin Scale score.Results85 patients underwent direct thromboaspiration as the firstline treatment during the study period. 100 direct thromboaspiration passes were performed. An angle of interaction of ≥125.5° significantly influenced the success of clot removal (P<0.001) with good sensitivity and specificity, in particular for occlusion of the middle cerebral and basilar artery. The combination of aspiration with a stent retriever based thrombectomy was a valid rescue treatment in cases of standalone direct thromboaspiration failure.ConclusionsIn our series, an angle of interaction between the aspiration catheter and the clot of ≥125.5° was significantly associated with successful clot removal. The prediction of the angle of interaction on pretreatment imaging may help operators to select the most adequate mechanical thrombectomy technique on a case by case basis.

Knapen R.R., Simon S.R., Robbe M.M., Jongkind J., Brans R., de Ridder I.R., van Oostenbrugge R.J., van Zwam W.H., van der Leij C.

Direct aspiration during endovascular treatment (EVT) for acute ischemic stroke (AIS) patients is safe and effective. The 'Soft torqueable catheter Optimized For Intracranial Access' (Sofia) catheter is commonly used. Data on differences between 5Fr and 6Fr Sofia is limited. Hence, we aimed to compare the clinical, technical, and safety outcomes between both Sofia catheters in AIS patients.

Wodarg F., Brouwer P., Power S., Gilvarry M., Mirza M., Conlon R., Johnson S., McCarthy R.

Background and purpose Mechanical thrombectomy (MT) for acute ischemic stroke (AIS) relies on efficient tracking of aspiration catheters through complex vascular anatomies. Differences in catheter design lead to variation in tracking performance which may only become apparent after use in patients. We developed an in-vitro methodology for evaluating aspiration catheter performance under a variety of pre-defined circumstances, that can be used during catheter development for design optimization. Methods Validation of the in-vitro methodology involved testing four large bore aspiration catheters on recreated challenging vascular access routes derived from patient angiograms. Two experienced neurointerventionalists conducted the tests under controlled physiological and procedural conditions. Each catheter design was evaluated across 30 unique anatomy-procedural set-up combinations. A fifth, prototype large bore catheter was evaluated by trained engineers to assess the applicability of the in-vitro test. Results Results from statistical analysis using a general linear model demonstrated the methodology's effectiveness in detecting significant tracking differences among catheter designs ( p < 0.01). Minimal inter-operator variability was observed ( p = 0.304), while procedural techniques significantly influenced tracking performance ( p < 0.01). The tortuosity of the arterial access route notably impacted catheter performance ( p < 0.01), with anatomical features revealing varying degrees of influence on desirable and undesirable catheter design aspects. Conclusion We successfully developed a test methodology for evaluating the trackability of large bore aspiration catheters intended for treating acute ischemic stroke with large vessel occlusions. This methodology offers a robust approach to pre-clinical design assessment, utilizing anatomical models that simulate real-world vascular challenges to enhance catheter optimization.

Piscopo A., Zanaty M., Dlouhy K.

The efficacy of using mechanical thrombectomy for proximal large vessel occlusions has been demonstrated in multiple large-scale trials and has further raised the question of its potential utility for distal medium and small vessel occlusions (DMSVOs). Their longer, more tortuous course and smaller corresponding vascular territories render a significant challenge for detection and intervention. The aim of this study is to provide a comprehensive overview of the current imaging and endovascular intervention options for DMSVOs and review the current works in the literature. Compared with traditional computed tomography angiography (CTA) and CT perfusion, recent advances such as multiphase CTA and maps derived from the time-to-maximum parameter coupled with artificial intelligence have demonstrated increased sensitivity for the detection of DMSVOs. Furthermore, newer generations of mini stent retrievers and thromboaspiration devices have allowed for the access and navigation of smaller and more fragile distal arteries. Preliminary studies have suggested that mechanical thrombectomy using this newer generation of devices is both safe and feasible in distal medium-sized vessels, such as M2. However, endovascular intervention utilizing such contemporary methods and devices must be balanced at the discretion of operator experience and favorable vascular anatomy. Further large-scale multicenter clinical trials are warranted to elucidate the indications for as well as to strengthen the safety and efficacy of this approach.

Benemerito I., Mustafa A., Wang N., Narata A.P., Narracott A., Marzo A.

The treatment of ischaemic stroke increasingly relies upon endovascular procedures known as mechanical thrombectomy (MT), which consists in capturing and removing the clot with a catheter-guided stent while at the same time applying external aspiration with the aim of reducing haemodynamic loads during retrieval. However, uniform consensus on procedural parameters such as the use of balloon guide catheters (BGC) to provide proximal flow control, or the position of the aspiration catheter is still lacking. Ultimately the decision is left to the clinician performing the operation, and it is difficult to predict how these treatment options might influence clinical outcome. In this study we present a multiscale computational framework to simulate MT procedures. The developed framework can provide quantitative assessment of clinically relevant quantities such as flow in the retrieval path and can be used to find the optimal procedural parameters that are most likely to result in a favorable clinical outcome. The results show the advantage of using BGC during MT and indicate small differences between positioning the aspiration catheter in proximal or distal locations. The framework has significant potential for future expansions and applications to other surgical treatments.

Settecase F., Kim W.T., English J.D.

Aspiration catheters are widely used for thrombectomy either alone or in combination with a stent-retriever, with a distal inner diameter and trackability keys to their success. In an illustrative case series, we report our clinical experience with AXS Vecta (Stryker Neurovascular, Fremont, CA, USA), available in both 0.071-inch and 0.074-inch distal inner diameters, including the first 2 Vecta 74 cases reported. A literature review on AXS Vecta is also provided. In our series, 9 thrombectomies were performed (Vecta 71: 2 M1, 5 M2 occlusions; Vecta 74: 1 M1 and 1 ICA-terminus occlusion). The AXS Vecta was successfully delivered to the target site in all cases. In 7 of 9 cases, the catheter was delivered over a Tenzing 7 delivery catheter (Route 92 Medical, San Mateo, CA, USA). For 2 of 9 combination approach cases, Vecta was delivered using the stent-retriever wire as a rail. The median improvement in NIHSS score during hospitalization was 9 (IQR 5–12). Successful mTICI 2C or 3 recanalization was achieved in 8 of 9 (89%) patients after a median 2 (IQR 1–2) passes. Our median groin-to-reperfusion time was 23 (IQR 12.5–32) minutes, with no procedural complications. Two previous clinical studies of a total of 29 patients treated with Vecta 71 reported successful mTICI 2b–3 recanalization in 89–90% of cases. The Median groin-to-reperfusion time was 30 minutes. Complications were seen in 2 of 29 (6.9%) cases (vessel perforation and/or intracerebral hemorrhage). These data support the efficacy, deliverability, and safety of AXS Vecta for mechanical thrombectomy.

Senturk C.