Embolus Retriever with Interlinked Cages versus other stent retrievers in acute ischemic stroke: an observational comparative study

In Vitro Analysis of the Efficacy of Endovascular Thrombectomy Techniques according to the Vascular Tortuosity Using 3D Printed Models

BACKGROUND AND PURPOSE

Achieving complete recanalization with the front-line endovascular thrombectomy device improves the outcome of acute stroke. The aim of this study was to evaluate whether various thrombectomy techniques including contact aspiration, stent retriever thrombectomy, and combination therapy differ in first-pass effect and distal emboli in acute large-vessel occlusion simulated using 3D printed nontortuous and tortuous cerebrovascular anatomy models.

MATERIALS AND METHODS

3D printed flow models were manufactured using angiographic data of nontortuous and acutely angulated tortuous vascular anatomy from real patients. Three thrombectomy techniques, contact aspiration, stent retriever, and combined methods, were tested under proximal protection with the balloon-guiding catheter. The first-pass effect and distal emboli rates were analyzed in addition to the thrombectomy-failure mechanisms of the respective techniques.

RESULTS

A total of 30 thrombectomy experiments were performed. The overall incidence of first-pass effect in the nontortuous and tortuous anatomy was 80.0% versus 46.7%. The overall incidence of distal emboli in the nontortuous and tortuous anatomy was 26.7% versus 46.7%. The contact aspiration technique showed better first-pass effect (80.0%) and distal emboli rates (20%) in the tortuous model compared with other techniques. The combined technique did not show remarkable superiority of the first-pass effect and distal emboli in either the nontortuous or tortuous anatomy. Shearing off of the thrombus was the main mechanism of thrombectomy failure in the combined group.

CONCLUSIONS

The tortuous vascular anatomy may worsen the first-pass effect and distal emboli rates. The combined techniques failed to show improvement in outcome due to the shearing-off phenomenon of the thrombus during retrieval.

Frictional force analysis of stent retriever devices using a realistic vascular model: Pilot study

Objective

To date, no vascular model to analyze frictional forces between stent retriever devices and vessel walls has been designed to be similar to the real human vasculature. We developed a novel in vitro intracranial cerebrovascular model and analyzed frictional forces of three stent retriever devices.

Methods

A vascular mold was created based on digital subtraction angiography of a patient's cerebral vessels. The vascular model was constructed using polydimethylsiloxane (PDMS, Dow Corning, Inc.) as a silicone elastomer. The vascular model was coated on its inner surface with a lubricating layer to create a low coefficient of friction (~0.037) to closely approximate the intima. A pulsatile blood pump was used to produce blood flow inside the model to approximate real vascular conditions. The frictional forces of Trevo XP, Solitaire 2, and Eric 4 were analyzed for initial and maximal friction retrieval forces using this vascular model. The total pulling energy generated during the 3 cm movement was also obtained.

Results

Results for initial retrieval force were as follows: Trevo, 0.09 ± 0.04 N; Solitaire, 0.25 ± 0.07 N; and Eric, 0.33 ± 0.21 N. Results for maximal retrieval force were as follows: Trevo, 0.36 ± 0.07 N; Solitaire, 0.54 ± 0.06 N; and Eric, 0.80 ± 0.13 N. Total pulling energy (N·cm) was 0.40 ± 0.10 in Trevo, 0.65 ± 0.10 in Solitaire, and 0.87 ± 0.14 in Eric, respectively.

Conclusions

Using a realistic vascular model, different stent retriever devices were shown to have statistically different frictional forces. Future studies using a realistic vascular model are warranted to assess SRT devices.

Endovascular administration of magnetized nanocarriers targeting brain delivery after stroke

The increasing use of mechanical thrombectomy in stroke management has opened the window to local intraarterial brain delivery of therapeutic agents. In this context, the use of nanomedicine could further improve the delivery of new treatments for specific brain targeting, tracking and guidance. In this study we take advantage of this new endovascular approach to deliver biocompatible poly(D-L-lactic-co-glycolic acid) (PLGA) nanocapsules functionalized with superparamagnetic iron oxide nanoparticles and Cy7.5 for magnetic targeting, magnetic resonance and fluorescent molecular imaging. A complete biodistribution study in naïve (n = 59) and ischemic (n = 51) mice receiving intravenous or intraarterial nanocapsules, with two different magnet devices and imaged from 30 min to 48 h, showed an extraordinary advantage of the intraarterial route for brain delivery with a specific improvement in cortical targeting when using a magnetic device in both control and ischemic conditions. Safety was evaluated in ischemic mice (n = 69) showing no signs of systemic toxicity nor increasing mortality, infarct lesions or hemorrhages. In conclusion, the challenging brain delivery of therapeutic nanomaterials could be efficiently and safely overcome with a controlled endovascular administration and magnetic targeting, which could be considered in the context of endovascular interventions for the delivery of multiple treatments for stroke.

Acute ischemic stroke endovascular therapy

Endovascular therapy (EVT) has become the standard treatment for large-vessel occlusion (LVO) acute ischemic stroke (AIS). EVT is now indicated in patients up to 24h from their last known well, provided that the patient meets specific clinical and imaging criteria. Improvements in thrombectomy devices, techniques, and operator experience have allowed successful EVT of ICA terminus, M1-MCA occlusions as well as proximal M2-MCA, basilar artery occlusions, and revascularization of tandem lesions. Mechanical thrombectomy failures still occur due to several factors, however, highlighting the need for further device and technical improvements. An ongoing debate exists regarding the need for pre-EVT thrombolytic agents, thrombectomy techniques, distal occlusions, anesthesia methods, the role of advanced neuroimaging, the treatment of patients with larger infarct core, and those presenting with milder stroke symptoms. Many of these questions are the subject of current or upcoming clinical trials. This review aims to provide an outline and discussion about the established recommendations and emerging topics regarding EVT for LVO AIS.

Mechanical thrombectomy using the new Tigertriever in acute ischemic stroke patients - A Swiss prospective multicenter study

PURPOSE

Tigertriever is a novel operator-adjustable clot retriever designed to enhance the operator's options to control the interaction of retriever and clot. The aim of this study was to assess the feasibility, safety and efficacy of the Tigertriever device system.

METHODS

Prospective multi-center registry study at three comprehensive stroke centers in Switzerland from 2017 to 2019 of patients with acute ischemic stroke (AIS) and large vessel occlusion (LVO) using Tigertriever as a first-line device.

RESULTS

30 AIS patients (median age 72.5 years (IQR 64-79), 50% women) with a median NIHSS on admission of 11 (IQR 6-13) and a median ASPECT score of 9 (IQR 7-10) were treated with the new Tigertriever and included in this study. The first-pass effect was 24% (n = 7). A good recanalization (eTICI 2 b/2c/3) was achieved in 94% of the cases. Median mRS at 90 days was 1 (IQR 1-2).

CONCLUSION

This study demonstrated feasibility, safety and effectiveness of the Tigertriever in AIS patients with LVO with a high reperfusion rate.

Embolus Retriever with Interlinked Cages (ERIC) versus conventional stent retrievers for thrombectomy: a propensity score-based analysis

BACKGROUND

The Embolus Retriever with Interlinked Cages (ERIC) is one of the latest devices for thrombectomies. It has several architectural features that are supposed to enhance its ability to remove clots and prevent distal emboli. We aimed to compare ERIC with standard stent retrievers (SRs) using propensity score (PS) matching.

METHODS

The clinical and radiological data of all consecutive patients treated with ERIC or standard FDA-approved stent retrievers were collected from a prospective multicenter registry. We compared procedural outcomes (recanalization rates according to the modified Thrombolysis In Cerebral Infarction (mTICI) score and procedural complications) and clinical outcomes (modified Rankin Scale (mRS) and mortality at 3 months). Matching of the populations with PS was performed to account for differences in baseline characteristics.

RESULTS

A total of 1230 patients were included. In both the PS-matched cohort (195 ERIC patients, 630 SR patients) and the inverse probability of treatment weighting PS-adjusted cohort (206 ERIC patients, 1024 SR patients) there was no difference in terms of successful recanalization (modified TICI score ≥2b), good clinical outcome (mRS=0-2 or equal to pre-stroke mRS), or mortality at 3 months. Patients treated with first-line ERIC had a higher rate of complete recanalization (mTICI 3); however, they also required more passes and more frequent rescue therapy than the SR patient group.

CONCLUSION

In a large multicenter registry with PS matching, the ERIC device provided equivalent angiographic and clinical results to conventional SRs.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov Unique identifier: NCT03776877.

ERASER

Background and Purpose- Using a novel study design with virtual comparators based on predictive modeling, we investigated whether next-generation mechanical thrombectomy devices improve outcomes in patients with ischemic stroke. We hypothesized that this new study design shows that a next-generation mechanical thrombectomy system is superior to intravenous tPA (tissue-type plasminogen activator) therapy (IVT) alone. Methods- ERASER (Eric Acute Stroke Recanalization) was an investigator-initiated, prospective, multicenter, single-arm (virtual 2-arm) study that evaluated the effectiveness of a new recanalization device together with a specific intermediate catheter (Embolus Retriever with Interlinked Cages/SOFIA, Microvention) in stroke patients with internal carotid artery or middle cerebral artery occlusions. The primary end point was the volume of saved tissue. Volume of saved tissue was defined as the difference of actual infarct volume and brain volume predicted to develop infarction using a machine learning model based on data from intravenous tPA therapy patients. Results- Eighty-one patients were enrolled. The median patient age was 71 years (interquartile range, 61-77). National Institutes of Health Stroke Scale score was 14 (interquartile range, 12-18). The actual infarct volume was smaller than predicted by the intravenous tPA therapy model, with a median volume of saved tissue of 50 mL (interquartile range, 19-103; P<0.0001). Good clinical outcome (modified Rankin Scale, 0-2 at 90 days) was observed in 48 out of 69 (70%). The recanalization rate (Thrombolysis in Cerebral Infarction 2b/3) was 95%. Conclusions- ERASER is the first mechanical thrombectomy study with a primary end point based on predictive analytics enabling intraindividual virtual comparisons. The next-generation mechanical thrombectomy method resulted in smaller infarcts than predicted after intravenous tPA therapy alone and showed a high rate of good clinical outcome. The novel study design with virtual comparisons is promising for further application and testing in the neurovascular arena. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT02534701.

Factors influencing harmonized health data collection, sharing and linkage in Denmark and Switzerland: A systematic review

Introduction

The digitalization of medicine has led to a considerable growth of heterogeneous health datasets, which could improve healthcare research if integrated into the clinical life cycle. This process requires, amongst other things, the harmonization of these datasets, which is a prerequisite to improve their quality, re-usability and interoperability. However, there is a wide range of factors that either hinder or favor the harmonized collection, sharing and linkage of health data.

Objective

This systematic review aims to identify barriers and facilitators to health data harmonization—including data sharing and linkage—by a comparative analysis of studies from Denmark and Switzerland.

Methods

Publications from PubMed, Web of Science, EMBASE and CINAHL involving cross-institutional or cross-border collection, sharing or linkage of health data from Denmark or Switzerland were searched to identify the reported barriers and facilitators to data harmonization.

Results

Of the 345 projects included, 240 were single-country and 105 were multinational studies. Regarding national projects, a Swiss study reported on average more barriers and facilitators than a Danish study. Barriers and facilitators of a technical nature were most frequently reported.

Conclusion

This systematic review gathered evidence from Denmark and Switzerland on barriers and facilitators concerning data harmonization, sharing and linkage. Barriers and facilitators were strictly interrelated with the national context where projects were carried out. Structural changes, such as legislation implemented at the national level, were mirrored in the projects. This underlines the impact of national strategies in the field of health data. Our findings also suggest that more openness and clarity in the reporting of both barriers and facilitators to data harmonization constitute a key element to promote the successful management of new projects using health data and the implementation of proper policies in this field. Our study findings are thus meaningful beyond these two countries.

Endovascular Treatment of Acute Ischemic Stroke

PURPOSE OF REVIEW

Endovascular thrombectomy (ET), the standard of treatment for emergent large vessel occlusion (ELVO) strokes, has been subject to rigorous efforts to further improve its usage and delivery for optimised patient outcomes. This review aims to provide an outline and discussion about the recently established and emerging recommendations regarding endovascular treatment of stroke.

RECENT FINDINGS

The indications for ET have expanded continually, with perfusion imaging now enabling selection of patients presenting 6-24 h after last-known-well, and improved device and operator proficiency allowing treatment of M2-MCA occlusions and tandem occlusions. Further inclusion of paediatric patients and patients with larger infarct core or milder stroke symptoms for ET has been proposed; however, this remains unproven. This growing applicability is supported by more efficient systems of care, employing modern techniques such as telemedicine, mobile stroke units and helicopter medical services. Ongoing debate exists regarding thrombolytic agent, thrombectomy technique, anaesthesia method and the role of advanced neuroimaging, with upcoming RCTs expected to provide clarification. The journey to further improving the efficacy of ET has advanced and diversified rapidly over recent years, involving improved patient selection, increased utility of advanced neuroimaging and ongoing device redevelopment, within the setting of more efficient, streamlined systems of care. This dynamic and ongoing influx of evidence-based refinements is key to further optimising outcomes for ELVO patients.