Intra-aneurysmal flow disruption after implantation of the Medina® Embolization Device depends on aneurysm neck coverage

Intrasaccular Flow Disruption: Examining Global Access and Research Trends

The Woven EndoBridge (WEB) and other intrasaccular flow disruptors show promise in treating intracranial aneurysms. We performed a bibliometric analysis to provide novel insights into the trends and trajectory of these devices. We systematically assessed bibliometric data such as citations, journals, study designs, open access status, and multi-institutional involvement for the top-cited articles on WEB and other disruptors. The top 100 cited studies on the WEB had citations from 7 to 144 (mean ± standard deviation 35.6 ± 29.5), while only 33 studies were published for other intrasaccular flow disruptors (4.24 ± 8.45). Of the other devices, the Contour has the most publications (n = 21). Retrospective reviews were the most common study design for both WEB and other intrasaccular devices. France published the most studies in the top 100 WEB papers (n = 35), while Germany led for other flow disruptors (n = 10). In all studies analyzed, no senior authors from Africa are present. The top 100 WEB publications had a higher mean citation count (35.6 vs. 4.24, P<0.001), higher mean citations per year (5.24 vs. 1.03, P<0.01), and a higher proportion of multi-institutional collaborations (44.0% vs. 12.1%, P<0.01) than other intrasaccular flow disruptors. In conclusion, countries with the most publications on WEB are not necessarily the ones leading the way with newer intrasaccular devices, while study designs remain similar. There is a limited contribution to the literature outside of Europe and North America. Our findings identify notable collaborators and trends, providing a snapshot of the field and a roadmap for future research.

Procedural Software Toolkit in the Armamentarium of Interventional Therapies: A Review of Additive Usefulness and Current Evidence

Interventional radiology is a fast-paced specialty that uses many advanced and emerging technological solutions. Several procedural hardware and software products are available commercially. Image-guided procedural software helps save time and effort in interventionist practice and adds precision to the intraoperative decisions made by the end user. Interventional radiologists, including interventional oncologists, have access to a wide range of commercially available procedural software that can be integrated into their workflow. However, the resources and real-world evidence related to such software are limited. Thus, we performed a detailed review of the current resources available, such as software-related publications, vendors' multimedia materials (e.g., user guides), and each software's functions and features, to compile a resource for interventional therapies. We also reviewed previous studies that have verified the use of such software in angiographic suites. Procedural software products will continue to increase in number and usage; these will likely be advanced further with deep learning, artificial intelligence, and new add-ins. Therefore, classifying procedural product software can improve our understanding of these entities. This review significantly contributes to the existing literature because it highlights the lack of studies on procedural product software.

A mini-review of intrasaccular flow diverters

Treatment of wide-necked complex intracranial aneurysms continues to challenge neurointerventionalists. Intrasaccular flow diverters have expanded the armamentarium considerably and are now used extensively. While five types of devices have already obtained the CE mark for use within Europe, only the Woven EndoBridge (WEB) device is approved by the US Food and Drug Administration. Other intrasaccular devices are the Luna/Artisse Aneurysm Embolization System (Medtronic), the Medina Embolic Device (Medtronic), the Contour Neurovascular System (Cerus), and the Neqstent Coil Assisted Flow Diverter (Cerus). This mini review will provide a compact overview of these devices and a summary of the current literature.

Treatment of experimental aneurysms with a GPX embolic agent prototype: preliminary angiographic and histological results

Background

Recently, liquid embolic agents have emerged for the endovascular treatment of cerebral aneurysms. Here we describe the in vivo performance of a novel liquid embolization agent (GPX Embolic Device).

Methods

Elastase-induced aneurysms were embolized with a GPX prototype under balloon assistance. Digital subtraction angiography was performed pre-deployment and immediately after, and at 5, 10, and 30 min post-deployment in 10 rabbits and at 1 month in 8 rabbits. The early post-deployment intra-aneurysmal flow was graded as unchanged, moderately diminished, or completely absent. At 1 month the status of aneurysm occlusion was evaluated. Adhesion to catheter material and migration of GPX was assessed.

Results

The mean aneurysm neck diameter, width, and height were 3.6±1.0 mm, 3.0±0.8 mm, and 7.4±1.4 mm, respectively. The mean dome-to-neck ratio was 0.9±0.2. Complete stagnation of intra-aneurysmal flow was observed in 9 of 10 aneurysms (90%) within 30 min of device deployment. One aneurysm showed moderately diminished intra-aneurysmal flow at 30 min. At 1 month, 8 aneurysms were completely occluded. There was no evidence of GPX adhesion to the catheter material. Histologically, a leukocyte and foreign body reaction to GPX was detectable 28 days after embolization.

Conclusions

This is the first preclinical study reporting the performance of a protype version of the GPX Embolic Device in a wide-neck aneurysm model. GPX showed promising results by achieving and maintaining high rates of complete angiographic occlusion, but may induce an inflammatory reaction.

The Cascade device - In vitro tests to assess coil protrusion into the parent vessel

BACKGROUND

Balloon and stent-assisted coiling of aneurysms have increased the number of aneurysms available for endovascular treatment. Newer devices that allow flow within the parent vessel but coverage at the neck have recently entered the market. The Cascade is a new non-occlusive fully retrievable neck-bridging support device that has been designed to provide temporary support during coil embolisation of intracranial aneurysms.

METHODS

Using a silicone aneurysm model three different aneurysms were catheterised with the coiling microcatheter placed in three different positions within each aneurysm - at the neck, centrally, and looped within the aneurysm. Multiple different coils were then deployed within each aneurysm with the Cascade device deployed across the neck to provide protection. In total 480 attempted coilings were performed. Aneurysm flow was used to calculate the change in intra-aneurysmal flow with the Cascade device deployed across the neck of the aneurysm.

RESULTS

We did not observe a single episode of coil protrusion through the Cascade mesh nor did we observe any coil protrusion into the parent vessel when the Cascade was deployed across the neck. There was an average flow velocity reduction of 23% with the Cascade device deployed across the neck of the aneurysm.

CONCLUSION

The Cascade device offers robust protection of the aneurysmal neck and parent vessel as well as inducing significant intra-aneurysmal flow velocity reduction.

Comparison of intra-aneurysmal flow modification using optical flow imaging to evaluate the performance of Evolve and Pipeline flow diverting stents

Background

Flow diverting stent (FDS) devices have revolutionized the treatment of large and complex brain aneurysms, but there is still room for improvement, particularly on the flow diversion properties and technical challenges associated with stent deployment. In this study we compared flow diversion properties between the new generation Surpass Evolve (Stryker) and the Pipeline Flex (Medtronic) devices by quantitatively evaluating intra-aneurysmal flow modification.

Methods

An in vitro experimental set-up was used, consisting of four patient-specific silicone models with internal carotid aneurysms and a circulating hemodynamic simulation system with pulsatile flow. The Evolve and Pipeline stents were deployed across the neck of each aneurysm model, in a randomized fashion, for a total of eight device deployments. A 60 frames/s digital subtraction angiography run was acquired before and after placement of each FDS. An optical flow-analysis method was used to measure intra-aneurysmal flow modification induced by the stent by calculating a mean aneurysm flow amplitude (MAFA) before and after stent placement and computing a ratio.

Results

Average MAFA ratio values calculated from pre- and post-stent placement were significantly lower after deployment of the Evolve (n=4, mean=0.62±0.09) compared with the Pipeline device (n=4, mean=0.71±0.06) (p=0.03).

Conclusions

Our in vitro results show that the Evolve stent had a superior flow diversion effect compared with the Pipeline stent, which—based on clinical evidence—suggest it may promote faster aneurysm occlusion rates in patients.

Neurovascular devices for the treatment of intracranial aneurysms: emerging and future technologies

Introduction: Despite numerous advances in the endovascular treatment of intracranial aneurysms (IAs), treatment in cases of wide-neck, complex configurations or branching locations remains challenging. Apart from the paradigm shift introduced by flow diverters, several other devices have seen the light or are under development in order to address these challenges.Areas covered: We performed a review of the novel implantable endovascular devices which have been introduced for the treatment of IAs, from 1 January 2014 to 1 September 2019, excluding classic flow diverter and intracranial stent designs.Expert opinion: Alternative designs have been proposed for the treatment of IAs at branching positions, which do not jail the side branches, with or without flow diversion effect, most of which with good initial outcomes. Endosaccular devices have also been proposed, some of which with lower initial total occlusion rates. Alternative materials such as biopolymers have also been proposed and are under bench research. Despite the challenges in the exploitation of some of the new devices, most of them seem to provide solutions to some current technical shortcomings. The exploitation of the biological phenomena and the physical properties of the devices will allow us to expand the therapeutic armamentarium for more complex IA cases.

The Contour-Early Human Experience of a Novel Aneurysm Occlusion Device

BACKGROUND AND PURPOSE

Endosaccular flow disruption is a recognized treatment options for treating both unruptured and ruptured aneurysms. The Contour device is designed to target the neck of an aneurysm and cause flow disruption within the aneurysm hence promoting thrombosis and neo-endothelialization at the neck. This article presents initial experiences with the Contour.

METHODS

The prospectively maintained database was retrospectively reviewed to identify patients treated with the Contour device. Demographic data, aneurysm characteristics, clinical result, and clinical and radiological follow-up information were recorded.

RESULTS

The review identified 3 patients (2 female), with 3 unruptured aneurysms, of average age 67 ± 8.7 years (range 62-77 years). The aneurysms were all located in the anterior circulation including one pericallosal, one at the A1-2 junction and one on the ICA bifurcation. The mean average dome height was 7.6 ± 0.62 mm (range 7.1-8.3 mm), dome width 5.7 ± 2 mm (range 3.5-7.5 mm), and neck width 3.6 ± 0.95 mm (range 2.5-4.2 mm). At follow-up angiography two of the aneurysms were completely occluded and one device had displaced into the aneurysm sac due to inappropriate positioning of the device. Of the patients one had minor stroke during the postoperative period but returned to baseline neurology. All patients were mRS 0 at last follow-up.

CONCLUSION

The Contour is a promising new aneurysm occlusion device. Further studies with longer term follow-up are required to determine the efficacy of this novel device.

Future Directions of Flow Diverter Therapy

The treatment of intracranial aneurysms has undergone a few very significant paradigm shifts in its history. Needless to say, microsurgery and surgical clipping served as the initial basis for successful treatment of these lesions. The pursuit of endovascular therapy subsequently arose from the desire to reduce the invasiveness of therapy. While the first breakthrough arose with Guido Guglielmi's invention of the detachable platinum coil, commercialized flow diverter therapy represents a disruptive therapy with a completely different paradigm for aneurysmal obliteration. This has not only altered the distribution of aneurysmal management strategies, but also opened the gateway to the treatment of previously inoperable lesions. With the basic flow diverter stent technology now considered an integral part of the neurointerventional armamentarium, we now consider what may lay in the future - including potential directions for research with regards to case selection; the location and type of aneurysms which may become routinely treatable; and modifications to the flow diverter, which may increase its utility and safety in terms of size, structural design, and surface modifications.

High frequency optical coherence tomography assessment of homogenous neck coverage by intrasaccular devices predicts successful aneurysm occlusion

BACKGROUND

High frequency optical coherence tomography (HF-OCT) is a novel intravascular imaging technology developed for use in the cerebral vasculature. We hypothesize that HF-OCT characterization of intrasaccular device neck coverage can prognosticate exclusion of the aneurysm from the circulation.

METHODS

Bifurcation and sidewall aneurysms were made in six dogs. Seven aneurysms were treated with next generation intrasaccular devices (NGID) and four with traditional platinum coils. HF-OCT was performed to interrogate gaps in the neck coverage, coil herniation, or acute thrombus formation. Animals were re-imaged at 7, 30, 90, and 180 days following aneurysm embolization. An automated image processing method segmented the devices at the neck of the aneurysm and quantified neck coverage. The largest coverage gap was used to predict aneurysm occlusion at 180 days.

RESULTS

No difference was found in occlusion rates between the coil and NGID groups (P=0.45). Successful segmentation of the NGID construct was achieved in all cases. A coverage gap >1 mm2 was found to predict failed aneurysm occlusion (P=0.047). This threshold was able to predict all cases of failed occlusion. The average number of devices needed to treat the aneurysm was lower in the NGID group (1.9 vs 6.75, P=0.009). HF-OCT showed strong agreement with scanning electron microscopy (bias 0.0024 mm2 (95% CI -0.0279, 0.0327)).

CONCLUSIONS

HF-OCT enables precise and accurate measurement of coverage gaps at the neck of aneurysms treated with intrasaccular devices in vivo. We provide in vivo evidence that uniform aneurysm neck coverage by intrasaccular devices is critical for aneurysm occlusion.

Endosaccular flow disruption: where are we now?

Endosaccular flow disruption is an innovative method of treating wide-necked complex aneurysms. Currently four types of devices have obtained the CE mark for use within Europe. These are the Woven EndoBridge device (WEB), the Luna Aneurysm Embolization System, the Medina Embolic Device (Medtronic), and the Contour Neurovascular System. The aim of this article is to provide an overview of these devices and to summarize the evidence in the literature pertaining to the treatment of intracranial aneurysms with them.

Medina embolization device for the treatment of intracranial aneurysms: 18 months’ angiographic results

Background and purpose

The Medina embolization device (MED) is a new flow disruption device combining the design of a detachable coil with an intrasaccular flow disrupter. Safety and short-term angiographic effectiveness of this device have recently been reported. However, long-term angiographic results are lacking. We report herein the 18 months’ angiographic outcome in patients treated for a wide-neck intracranial aneurysm with the MED.

Materials and methods

Nineteen patients (17 female, mean age 50 years) with 20 wide-neck intracranial aneurysms (six ruptured; 14 unruptured) were treated by the MED between January 2015 and June 2016. Procedure-related complications were systematically recorded; discharge and 6–9 months' follow-up modified Rankin Scale scores were assessed. Angiographic mid-term and long-term follow-up were performed with a mean delay of 6.4±1.5 months (n=16 aneurysms) and 17.7±4.2 months (n=15 aneurysms), respectively. Occlusion rates were evaluated after the procedure and at the mid-term and long-term follow-up using the Roy-Raymond scale.

Results

Embolization with the MED was feasible in all except two cases (2/20, 10%). One per-procedural perforation was recorded (1/20, 5%) and one MED deployment failed because of the aneurysm’s shape (1/20, 5%). Three cases of thromboembolic complications were observed (3/20, 15%). Only one thromboembolic complication was responsible for clinical sequelae. Grade A occlusion rate was 61% (11/18) after the procedure, 75% at 6 months' follow-up (12/16), and 80% (12/15) at long-term follow-up. Two cases (2/18, 11%) of recanalization at mid-term were documented angiographically. No recanalization occurred between the mid-term and long-term follow-up.

Conclusion

MED is a hybrid embolization device, combining properties of a conventional coil with those of an intrasaccular flow disrupter. Our series focusing on long-term angiographic follow-up shows a satisfactory long-term occlusion rate. Larger series with longer angiographic follow-up times are warranted to confirm these preliminary results.

The Combined Use of Intraluminal and Intrasaccular Flow Diversion for the Treatment of Intracranial Aneurysms: Report of 25 Cases

PURPOSE

The Medina Embolic Device (MED) is a new intrasaccular device with promising early results. Previously we documented our initial experience of this device both alone and in combination with other devices including flow diverter stents (FDS). We sought to determine the effect of the MED + FDS strategy for the treatment of selected aneurysms.

MATERIALS AND METHODS

We performed a retrospective analysis of prospectively collected data to identify all patients with aneurysms treated using both the MED and intraluminal FDS. We present our technical success rate, early and mid-term angiographic follow-up, and clinical outcome data.

RESULTS

We identified 25 non-consecutive patients. The treatment was staged in 9 patients and in a single session 16 patients. The average age was 61±12.8 years (range 40-82). The average fundus height was 11±3.6 mm and average fundus width was 10.1±3.4 mm. In the staged cohort (n=9) at delayed angiography (mean 10 mths) 8 aneurysms (89%) showed complete exclusion (mRRC 1) and in one patient there was a parent vessel occlusion. In the simultaneous cohort delayed angiography (n=10, mean 8.1 months) demonstrated complete occlusion (mRRC 1) in 6 aneurysms (60%), 3 neck remnants (mRRC 2) (30%) and 1 patient (10%) showed persistent aneurysmal filling (mRRC 3a). There were 5 complications with permanent morbidity (mRS >2) in two patients. There were no mortalities.

CONCLUSION

The MED can be successfully used in combination with intraluminal FDS and in selected aneurysms this may represent an alternative to FDS and adjunctive coiling.