Mechanical Thrombectomy in Acute Ischemic Stroke Using a Manually Expandable Stent Retriever (Tigertriever) : Preliminary Single Center Experience

Multi-objective RVEA optimization of a closed-cell segmented stent retriever for balancing biomechanical forces

Mechanical thrombectomy for acute ischemic stroke (AIS) faces significant challenges in complex vascular geometries, where existing stent retrievers often struggle to capture thrombus effectively. This study introduces an enhanced closed-cell segmented flexible (ECSF) stent retriever designed to address these challenges and improve thrombus capture, particularly in intricate vascular environments. Fabricated from superelastic Nitinol, the ECSF stent underwent a multi-objective optimization process using the RVEA algorithm to balance key performance metrics, including radial resistive force, hoop force, chronic outward force, and volume, while ensuring the strain remained within Nitinol's superelastic limit. Finite element analysis demonstrated the ECSF stent's superior mechanical performance compared to a commercial stent. In vitro experiments further validated its effectiveness in capturing and removing thrombus in complex vessel conditions, highlighting its potential as a promising solution for AIS treatment, even under suboptimal deployment conditions.

Dumbbell-shaped thrombectomy device for cerebral venous sinus thrombus removal with controllable axial and longitudinal maneuverability

Cerebral venous sinus thrombosis (CVST) is frequently observed in younger adults and features in large thrombus volume. Due to the triangular-like cross-sectional shape and large diameter of the superior sagittal sinus, all the commercially available artery stent retrievers are not suitable for venous vessels. In this study, a dumbbell-like stent was designed and fabricated by 3D braided technology using NiTi wires; it was manually rotatable and stretchable with controlled length/diameter ratios (2.6-14.0) and reciprocating maneuverability. Computational modeling and an in vitro study were conducted to evaluate the mechanical properties of this device and its ability to trap and remove thrombi from occluded venous vessels was verified by using a swine model. A single-center retrospective clinical study of 10 patients using the Venus-TD to treat patients with CVST was also conducted. Pre/postoperative thrombus volume in 10 patients was quantitatively analysed (12 855.3 ± 6417.1 vs. 2373.1 ± 2759.0 mm³, P < 0.001) with a high recanalization rate, yielding favorable clinical outcomes. This study offers a novel treatment option for patients with extensive CVST.

The initial experience with the Embotrap III stent-retriever in a real world setting

MATERIALS AND METHODS

We performed a retrospective review of our prospectively maintained database to identify all patients treated with the Embotrap 3 stent-retriever between January 2021 and January 2022. We recorded the baseline demographics, NIHSS, ASPECT score and clot characteristics, first pass and final eTICI scores, complications and 90 day mRS.

RESULTS

One hundred and ten patients met the inclusion criteria, average age 69 ± 14 years, 50% were male (n = 55). The median NIHSS at presentation was 18 (range 3-30) and 58.2% received IV tPA prior to MT. The median ASPECT score on plain CT was 8 with average clot length 20.2 ± 14.8 mm (n = 93). The first pass effect (FPE) was seen in 41.8% of cases with modified FPE seen in 59.1%. A 24-hour CT scan (n = 97) showed median ASPECTs of 7. 43.8% of patients achieve mRS ≤ 2 at 90-day mRS (n = 64).

CONCLUSION

The Embotrap 3 stent-retriever has a high rate of FPE and final recanalization in this real world cohort of patients.

Neuroendovascular Rescue 2025: Trends in Stroke Endovascular Therapy

Neuroendovascular rescue of patients with acute ischemic stroke caused by a large arterial occlusion has evolved throughout the first quarter of the present century, and continues to do so. Starting with the intra-arterial instillation of thrombolytic agents via microcatheters to dissolve occluding thromboembolic material, the current status is one that includes a variety of different techniques such as direct aspiration of thrombus, removal by stent retriever, adjuvant techniques such as balloon angioplasty, stenting, and tactical intra-arterial instillation of thrombolytic agents in smaller branches to treat no-reflow phenomenon. The results have been consistently shown to benefit these patients, irrespective of whether they had already received intravenous tissue-type plasminogen activator or not. Improved imaging methods of patient selection and tactically optimized periprocedural care measures complement this dimension of the practice of neurointervention.

Early neurological changes following endovascular therapy for acute stroke due to intracranial atherosclerotic disease

BACKGROUND

Endovascular therapy (EVT) reduces functional disability in patients with acute large vessel occlusion (LVO). However, the early neurological change after EVT may be limited in patients with intracranial atherosclerotic disease (ICAD).

METHODS

We analyzed the Japanese Registry of NeuroEndovascular Therapy (JR-NET) 4 which was a retrospective, nationwide, multicenter registry of patients with LVO between 2015 and 2019. We compared the early neurological change, efficacy and safety of EVT for acute LVO in ICAD and other etiologies. The primary outcome was NIHSS improvement ≥10 points, and secondary outcome were NIHSS worsening ≥4 points 7 days after EVT, effective reperfusion rate, 30-day functional outcomes, and safety outcomes.

RESULTS

Among the 6710 enrolled patients, 610 (9.1%) had ICAD. The ICAD group was younger (mean 72.0 vs. 75.8 years) and predominantly male (63.4% vs. 56.0%), had lower NIHSS scores before EVT (median 16 vs. 18), and underwent percutaneous transluminal angioplasty and stenting more frequently (43.0% vs. 4.4%, 12.3% vs. 4.4%). In the ICAD group, NIHSS improvement was significantly lower (adjusted odds ratio (aOR) [95% confidence interval (95%CI)] 0.52 [0.41-0.65]), NIHSS worsening was significantly higher (aOR [95%CI] 1.76 [1.31-2.34]), and effective reperfusion was significantly lower (aOR [95%CI] 0.47 [0.36-0.60]). Fewer patients with ICAD had modified Rankin scale 0-2 at 30 days (aOR [95%CI] 0.60 [0.47-0.77]). The risk of acute reocclusion was more prominent in the ICAD group (aOR [95%CI] 4.03 [1.98-8.21]).

CONCLUSIONS

Improvement in neurological severity after EVT was lower in patients with LVO and ICAD.

The effect of actuation frequency on clot integration with the Tigertriever device: A preliminary in vitro study

BACKGROUND

The Tigertriever stent retriever (Rapid Medical) can be actively expanded and contracted by the operator, which allows for several actuation-related parameters to be optimized to potentially improve device efficacy. These parameters have not yet been evaluated. We conducted a benchtop study to evaluate the effect of actuation frequency on clot integration within the stent.

METHODS

A Tigertriever 17 device was deployed within a biological clot analog placed in a straight tube. The device was actuated between the maximally contracted and maximally expanded states with three different frequencies: passive (one-time opening, n = 6), slow (20 s/cycle, n = 6), and fast (5 s/cycle, n = 7). A flat-detector CT scan was acquired, the clot and stent wires were segmented, and the boundaries of the clot and stent wires were calculated on each axial slice. The intersection between the stent and clot boundaries throughout the volume was defined as the volume of clot integrated within the stent. The clot integration factor (ratio of integrated clot volume to total clot volume) was then statistically compared between the three frequencies as an estimate of clot capture efficiency.

RESULTS

The clot integration factor was significantly higher (23% increase, p = 0.01) with the fast actuation as compared to the passive and slow actuations, with a post hoc test showing no difference (p > 0.05) between the passive and slow groups.

CONCLUSIONS

Faster actuation frequencies may result in improved clot integration with the Tigertriever device. This effect needs to be validated by clinical data.

Radially adjustable stent retriever for mechanical thrombectomy in acute ischemic stroke: Improved first-pass effect with rapid-inflation deflation technique

INTRODUCTION

Evidence for improved first-pass effect with the novel radially adjustable radio-opaque stent retriever Tigertriever is lacking.

OBJECTIVE

To compare improvement in first pass success with Tigertriever using two different techniques-rapid inflation deflation (RID) and suction thrombectomy (ST).

METHODS

Retrospective analysis of patients with acute ischemic stroke who underwent mechanical thrombectomy with Tigertriever at a single comprehensive stroke center.

RESULTS

Thirty patients were included. Mean age was 72.8 years. Twelve patients (48%) experienced successful first passes with Tigertriever. Successful revascularization (modified thrombolysis in cerebral infarction (mTICI) 2b/3) was achieved in all (100%) patients who received RID or ST technique for thrombectomy. Good clinical outcome (modified Rankin score = 0-2) was noted in 40% (n = 10). Total mortality in the cohort was 8% (n = 2). RID and ST groups comprised of 10 and 15 patients, respectively. Five patients underwent MT with Tigertriever as a rescue device.

RID VS ST

No difference was noted in mean age (p = 0.27), gender (p = 0.29), location of occlusion (p = 0.46), and device used for first pass (p = 0.57). A 70% first-pass success rate in RID group and 37.5% in ST group was noticed (p = 0.06). Mean time from groin puncture to reperfusion (TICI 2b//3) was statistically similar (p = 0.29, RID: 19.9 min vs ST: 25 min). Both groups noted a 100% complete recanalization rate. The rate of mortality between the two groups were not statistically different (p = 0.46).

CONCLUSION

The preliminary first-pass success rates of RID technique with Tigertriever compared to ST technique, are encouraging. Longitudinal studies with longer follow up are needed to elucidate the smaller learning curve with this device.

Mechanical thrombectomy of large vessel occlusion using adjustable vs. self-expanding stent-retriever-Comparison of Tigertriever device with stent-like stent-retrievers: A propensity score analysis

Background

Stent-retrievers used for mechanical thrombectomy are self-expanding tubular stent-like devices with modified mesh structures for clot removal. Tigertriever is designed to provide manual control of its diameter and curvature.

Methods

A retrospective single-center study was performed to compare Tigertriever with SolitaireX and pRESET (stent-like stent-retrievers group) using propensity score analysis. Patients treated in a comprehensive stroke center due to large vessel occlusion between January 2016 and August 2021 were evaluated. Baseline characteristics and treatment results were compared between these groups before and after pair matching.

Results

There were 140 patients (60 in Tigertriever and 80 in the stent-like stent-retriever group). In propensity score analysis, 52 matched pairs were selected in Tigertriever and stent-like stent-retriever groups. The Tigertriever group had a better successful first pass revascularization rate [46 vs. 23%, OR (95% CI): 1.7 (1.1-2.9), p = 0.013] and 14-min shorter groin-to-revascularization time (51 vs. 65 min. p = 0.017). There were no significant differences between Tigertriever and stent-like stent-retriever groups in the following: favorable mRS 3 months, favorable recanalization rate, and symptomatic intracerebral hemorrhages. There were no observed periprocedural adverse events related to Tigertriever, SolitaireX, or pRESET.

Conclusion

Tigertriever had a significantly better successful first pass revascularization rate and shorter groin-to-revascularization time in the analysis done before and after propensity score matching with stent-like stent-retrievers. Tigertriever is comparable to stent-like stent-retrievers regarding mortality at 3 months, favorable mRS at 3 months, favorable recanalization rate, or symptomatic cerebral hemorrhagic events.

Comparing Tigertriever 13 to other thrombectomy devices for distal medium vessel occlusion: A systematic review and meta-analysis

BACKGROUND

There is limited evidence on the optimal endovascular strategy for treatment of distal medium-vessel occlusions (DMVO). The low-profile Tigertriever 13 stent-triever shows early promise as an adaptable device that can navigate the distal vasculature without increasing complication risk in DMVO.

METHODS

Using Nested Knowledge, we screened literature for RCTs and cohort studies on the endovascular treatment of DMVO. The primary outcome was reperfusion success, as measured by thrombolysis in cerebral infarction (TICI) ≥ 2b and secondary outcomes included rate of symptomatic intracranial hemorrhage (sICH), mortality at 90 days, and modified Rankin scale (mRS) scores 0-2 at 90 days. A random-effects model was used to compute pooled prevalence rates and their corresponding 95% confidence intervals (CI).

RESULTS

Eleven studies with 1402 patients, 167 patients treated by Tigertriever 13 and 1235 patients treated by other devices, were included in the meta-analysis. The rate of reperfusion success was similar in patients treated by Tigertriever 13 (83.2% [95% CI: 71.5-96.7%]) versus other devices (81.6% [95% CI: 75.3-88.4%], p > 0.05). The rate of sICH was also similar in patients treated by Tigertriever 13 (7.2% [95% CI: 4.1-12.5%]) versus other devices (6.9% [95% CI: 5.5-8.8%]). There was significant heterogeneity in the reporting of mortality and mRS.

CONCLUSIONS

Tigertriever 13 had similar rates of reperfusion success and sICH as other devices used for the treatment of DMVO. Heterogeneity in data element reporting prevented further analyses. Further studies evaluating Tigertriever 13 and other potential devices in DMVO should attempt to harmonize data element reporting.

The Anch'Or Harpoon Technique With a Manually Expandable Stentretriever (Tigertriever 13), a Technical Note

Background and purpose

Stent and balloon anchor techniques have been described to obtain distal support and straighten catheter loops, stabilize microcatheters in giant aneurysms, or access distal tortuous anatomy during thrombectomy. These techniques require catheterization of distal arteries with a microcatheter but tortuosity and length issues may render it challenging, precluding the distal unsheathing of a classical auto-expandable stentretriever with the anchor technique.

Methods

Therefore, we developed the so-called Anch'Or Harpoon Technique using a manually expandable stent retriever, the Tigertriever 13 (Rapid Medical, Yoqneam, Israel). Here, the stent retriever is not unsheathed but pushed out of a microcatheter, and then advanced as far as possible before manual opening.

Results and conclusion

This technique may be used in 2 different situations. First, in the case of vessel tortuosity if the microcatheter can't be advanced as far as the physician wants: the Tigertriever 13 could be delivered through the microcatheter without having to unsheathe it, and be advanced and opened distally to its microcatheter to establish a stable anchor prior to advancing the guiding, intermediate, and micro-catheters (Anchor technique). The second situation is when distal occlusions lead to length issues; the microcatheter may be too short to cross a distal clot: the Tigertriever 13 could then be pushed out of the microcatheter, and be used to cross a sub-occlusive clot as it has a soft shaped distal tip and the physician has a visual on the artery beyond the sub-occlusion. Then, the Tigertriever would be manually expanded through the clot and retrieved (Harpoon technique) to obtain a recanalization.

The Tigertriever 13 for mechanical thrombectomy in distal and medium intracranial vessel occlusions

PURPOSE

To report our two-center initial experience using the Tigertriever 13 in the treatment of acute stroke of distal, medium vessel occlusions (DMVO).

METHODS

We performed a retrospective analysis of all patients treated by mechanical thrombectomy using the Tigertriever 13 device (a manually expandable low profile stent retriever) due to an acute DMVO. Locations included the anterior, middle, and posterior cerebral artery in the A2 and A3, the M3 and M4, and the P2 or P3 segment and the superior cerebellar artery.

RESULTS

Forty-three patients with 45 DMVOs underwent MTE using the Tigertriever 13 with the intention-to-treat approach between May 2019 and December 2020. After a median of two thrombectomy maneuvers, the successful recanalization rate (mTICI 2b-3) was 84.4% (38/45) with a first pass effect of 26.7% (12/45). The rate of symptomatic intracranial hemorrhages (sICH) and subarachnoid hemorrhages (SAH) was 7.0% (3/43) and 14.0% (6/43), respectively. At discharge, 53.5% (23/43) of the patients had a favorable clinical outcome (mRS 0-2).

CONCLUSION

Mechanical thrombectomy in DMVOs using the Tigertriever 13 leads to high recanalization rates. The incidence of mostly asymptomatic hemorrhagic events appears higher compared to MTE procedures in LVOs. Further studies will help to identify anatomic and clinical criteria to define a guideline for MTE in DMVOs.

Evidence-Based Updates to Thrombectomy: Targets, New Techniques, and Devices

Endovascular thrombectomy (EVT) has been validated in several randomized controlled trials in recent years for its efficacy in the treatment of acute ischemic strokes (AIS) and is now the standard of care according to international guidelines. However, in about 20% of EVT procedures, recanalization is not achieved, and over 50% of patients who undergo EVT still do not have good functional outcome. In this article, we provide an extensive review of the latest evidence and developments in the field of EVT, with particular focus on the factors that improve patient outcomes. These factors include new and adjunctive techniques such as combination of direct aspiration and stent retriever, intra-arterial urokinase or 2b/3a inhibitors, rescue stenting, as well as novel devices including balloon guide catheters and the newer generations of aspiration catheters and stent retrievers. We also examined the latest notion of using first-pass effect (FPE) as the target to achieve during EVT, which has been associated with an improved functional outcome. While the field of EVT has been rapidly evolving, further research is required in specific AIS patient populations such as those with large ischemic core, late presentation beyond 24 h, posterior circulation strokes, and with distal medium vessel occlusion or tandem lesions to better assess its efficacy and safety.

Mechanical Thrombectomy in Acute Terminal Internal Carotid Artery Occlusions Using a Large Manually Expandable Stentretriever (Tiger XL Device): Multicenter Initial Experience

Background: The recently introduced Tigertriever XL Device for treatment of cerebral vessel occlusions combines manual adjustability and maximum length in one device. In this study, we report our initial experience with the Tigertriever XL in terminal ICA occlusions. Methods: Retrospective multicenter analysis of acute terminal ICA occlusions treated by mechanical thrombectomy using the Tigertriever XL Device. Results: 23 patients were treated using the Tigetriever XL due to an acute occlusion of the terminal ICA. The overall successful reperfusion rate after a median of two maneuvers using the Tigertriever XL Device was 78.3% (mTICI 2b-3). In 43.5% (10/23) additional smaller devices were applied to treat remaining occlusions in downstream territories, which resulted in a final successful reperfusion rate of 95.7%. Device related complications did not occur. Two symptomatic intracerebral hemorrhages (sICH) were observed. Conclusions: The Tigertriever XL Device might be a helpful tool in the treatment of ICA terminus occlusions with large clot burden resulting in high reperfusion rates. This is mainly related to the manual adjustability of the device combined with the maximum length.

Thrombectomy for Acute Ischemic Stroke With a New Device-Skyflow: Study Protocol for a Prospective, Multicenter, Stratified Randomized, Single-Blinded, Parallel, Positive Controlled, Non-inferiority Clinical Trial

Background: Stent retriever thrombectomy is the standard treatment for acute ischemic stroke (AIS) with large vessel occlusion (LVO) in anterior circulation. The aim of the trial is to evaluate whether the new thrombectomy device-Skyflow can achieve the same safety and efficacy as Solitaire FR in the treatment. Method: This study is a prospective, multicenter, stratified randomized, single blind, paralleled, positive controlled, non-inferiority clinical trial. The safety and efficacy of vascular recanalization in AIS patients who are treated with either a new thrombectomy device-Skyflow or with Solitaire FR and within 8 h of symptom onset will be compared. A total of 192 patients will be enrolled, each group with 96 patients. The primary endpoint is successful recanalization rate after the operation. The secondary efficacy endpoints are the time from artery puncture to successful recanalization (mTICI 2b-3), NIHSS scores of 24 h (18-36 h), and 7 ± 2 days after the operation, mRS scores, and the rate of patients with mRS 0-2 scores 90 ± 14 days after the operation, and the success rate of instrument operation. The safety endpoints are the rate of symptomatic intracranial hemorrhage (sICH) and subarachnoid hemorrhage at 24 h (18-36 h) post-operation, incidence of adverse events (AE) and serious adverse events (SAE), all-cause mortality, and incidence of device defects. Discussion: This trial will provide information on the safety and efficacy of Sky-flow stent retriever in the treatment of AIS patients with anterior circulation LVO. The success of this trial will be the basis for the product to be finally officially listed and applied in China. Trial registration: Registered on 11 March 2018 with Chinese clinical trial registry. Registration number is ChiCTR1800015166.

Thrombectomy for Primary Distal Posterior Cerebral Artery Occlusion Stroke: The TOPMOST Study

Importance

Clinical evidence of the potential treatment benefit of mechanical thrombectomy for posterior circulation distal, medium vessel occlusion (DMVO) is sparse.

Objective

To investigate the frequency as well as the clinical and safety outcomes of mechanical thrombectomy for isolated posterior circulation DMVO stroke and to compare them with the outcomes of standard medical treatment with or without intravenous thrombolysis (IVT) in daily clinical practice.

Design, Setting, and Participants

This multicenter case-control study analyzed patients who were treated for primary distal occlusion of the posterior cerebral artery (PCA) of the P2 or P3 segment. These patients received mechanical thrombectomy or standard medical treatment (with or without IVT) at 1 of 23 comprehensive stroke centers in Europe, the United States, and Asia between January 1, 2010, and June 30, 2020. All patients who met the inclusion criteria were matched using 1:1 propensity score matching.

Interventions

Mechanical thrombectomy or standard medical treatment with or without IVT.

Main Outcomes and Measures

Clinical end point was the improvement of National Institutes of Health Stroke Scale (NIHSS) scores at discharge from baseline. Safety end point was the occurrence of symptomatic intracranial hemorrhage and hemorrhagic complications were classified based on the Second European-Australasian Acute Stroke Study (ECASSII). Functional outcome was evaluated with the modified Rankin Scale (mRS) score at 90-day follow-up.

Results

Of 243 patients from all participating centers who met the inclusion criteria, 184 patients were matched. Among these patients, the median (interquartile range [IQR]) age was 74 (62-81) years and 95 (51.6%) were female individuals. Posterior circulation DMVOs were located in the P2 segment of the PCA in 149 patients (81.0%) and in the P3 segment in 35 patients (19.0%). At discharge, the mean NIHSS score decrease was -2.4 points (95% CI, -3.2 to -1.6) in the standard medical treatment cohort and -3.9 points (95% CI, -5.4 to -2.5) in the mechanical thrombectomy cohort, with a mean difference of -1.5 points (95% CI, 3.2 to -0.8; P = .06). Significant treatment effects of mechanical thrombectomy were observed in the subgroup of patients who had higher NIHSS scores on admission of 10 points or higher (mean difference, -5.6; 95% CI, -10.9 to -0.2; P = .04) and in the subgroup of patients without IVT (mean difference, -3.0; 95% CI, -5.0 to -0.9; P = .005). Symptomatic intracranial hemorrhage occurred in 4 of 92 patients (4.3%) in each treatment cohort.

Conclusions and Relevance

This study suggested that, although rarely performed at comprehensive stroke centers, mechanical thrombectomy for posterior circulation DMVO is a safe, and technically feasible treatment option for occlusions of the P2 or P3 segment of the PCA compared with standard medical treatment with or without IVT.

New Class of Radially Adjustable Stentrievers for Acute Ischemic Stroke: Primary Results of the Multicenter TIGER Trial

Supplemental Digital Content is available in the text.

Background and Purpose:

The Tigertriever is a novel, radially adjustable, fully visible, stentriever that permits the operator to align radial expansion with target vessel diameters. This multicenter trial compared the Tigertriever’s effectiveness and safety compared with established stent retrievers.

Methods:

Single arm, prospective, multicenter trial comparing the Tigertriever to efficacy and safety performance goals derived from outcomes in 6 recent pivotal studies evaluating the Solitaire and Trevo stent-retriever devices with a lead-in and a main-study phase. Patients were enrolled if they had acute ischemic stroke with National Institutes of Health Stroke Scale score ≥8 due to large vessel occlusion within 8 hours of onset. The primary efficacy end point was successful reperfusion, defined as core laboratory-adjudicated modified Thrombolysis in Cerebral Ischemia score 2b-3 within 3 passes of the Tigertriever. The primary safety end point was a composite of 90-day all-cause mortality and symptomatic intracranial hemorrhage. Secondary efficacy end points included 3-month good clinical outcome (modified Rankin Scale score 0–2) and first-pass successful reperfusion.

Results:

Between May 2018 and March 2020, 160 patients (43 lead-in, 117 main phase) at 17 centers were enrolled and treated with the Tigertriever. The primary efficacy end point was achieved in 84.6% in the main-study phase group compared with the 63.4% performance goal and the 73.4% historical rate (noninferiority P<0.0001; superiority P<0.01). The first pass successful reperfusion rate was 57.8%. After all interventions, successful reperfusion (modified Thrombolysis in Cerebral Ischemia score ≥2b) was achieved in 95.7% and excellent reperfusion (modified Thrombolysis in Cerebral Ischemia score 2c-3) in 71.8%. The primary safety composite end point rate of mortality and symptomatic intracranial hemorrhage was 18.1% compared with the 30.4% performance goal and the 20.4% historical rate (noninferiority P=0.004; superiority P=0.57). Good clinical outcome was achieved in 58% at 90 days.

Conclusions:

The Tigertriever device was shown to be highly effective and safe compared with Trevo and Solitaire devices to remove thrombus in patients with large-vessel occlusive stroke eligible for mechanical thrombectomy.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03474549.