Intra-aneurysmal hemodynamics: evaluation of pCONus and pCANvas bifurcation aneurysm devices using DSA optical flow imaging

In vitro flow diversion effect of the ReSolv stent with the shelf technique in a bifurcation aneurysm model

BACKGROUND

Flow-diverting stents are not currently indicated for the treatment of bifurcation aneurysms, and some case series have demonstrated low occlusion rates, possibly due to a lack in neck coverage. The ReSolv stent is a unique hybrid metal/polymer stent that can be deployed with the shelf technique in order to improve neck coverage.

METHODS

A Pipeline, unshelfed ReSolv, and shelfed ReSolv stent were deployed in the left-sided branch of an idealized bifurcation aneurysm model. After determining stent porosity, high-speed digital subtraction angiography runs were acquired under pulsatile flow conditions. Time-density curves were created using two region of interest (ROI) paradigms (total aneurysm and left/right), and four parameters were extracted to characterize flow diversion performance.

RESULTS

The shelfed ReSolv stent demonstrated better aneurysm outflow alterations compared to the Pipeline and unshelfed ReSolv stent when using the total aneurysm as the ROI. On the left side of the aneurysm, there was no significant difference between the shelfed ReSolv stent and the Pipeline. On the right side of the aneurysm, however, the shelfed ReSolv stent had a significantly better contrast washout profile than the unshelfed ReSolv stent and the Pipeline stent.

CONCLUSIONS

The ReSolv stent with the shelf technique demonstrates the potential to improve flow diversion outcomes for bifurcation aneurysms. Further in vivo testing will help to determine whether the additional neck coverage leads to better neointimal scaffolding and long-term aneurysm occlusion.

[pConus device for endovascular treatment of basilar bifurcation aneurysms]

Aneurysm occlusion with microcoils is an effective and safe procedure. However, bifurcation aneurysms usually have a wide neck, and their occlusion is still a difficult objective.

OBJECTIVE

To evaluate the efficacy and safety of bifurcation stents in the treatment of basilar bifurcation aneurysms.

MATERIAL AND METHODS

A retrospective analysis included 34 patients with basilar bifurcation aneurysms between 2016 and 2022. The pConus bifurcation stent was used as a stent-assistance for endovascular occlusion of aneurysms with microcoils. We analyzed technical features of stent implantation and clinical results of endovascular treatment. Mean aneurysm dimension was 8.4 mm, neck size - 4.6 mm. Preoperative MSR score 0-2 was observed in 94.7% of patients, 3-5 scores - in 5.3% of patients.

RESULTS

There were no significant changes in functional status early after surgery (MSR grading system). Total aneurysm occlusion was achieved in 67.6% of patients, subtotal - 17.6% of cases, partial - 14.8%. There were no technical or early postoperative clinical complications. Six months after surgery, total occlusion was observed in 77.8% of patients, subtotal occlusion - 14.8%, partial occlusion - 4%. MSR score 0-2 was observed between 3 and 12 months after surgery. One patient died from other cause rather aneurysm. Redo intervention due to aneurysm recanalization was performed in 1 patient.

CONCLUSION

The pConus bifurcation stent is effective and safe in endovascular treatment of basilar bifurcation aneurysms of the most complex configuration. There was a minimal risk of aneurysm recanalization in long-term postoperative period.

Effect and Blood Flow Parameters of Biomaterials-Based Endovascular Interventional Embolization and Craniotomy Clipping in the Treatment of Cerebral Aneurysms

Objective: The effects of interventional embolization and craniotomy clipping on the treatment of intracranial aneurysms were investigated in this study, as well as their influence on the hemodynamics of postoperative patients. Methods: 102 patients with intracranial aneurysms were selected as the research objects, and they were rolled into an experimental (group A) and a control group (group B) according to the random number table method, with 51 cases in each group. The group A was treated with intravascular interventional embolization, and the group B received craniotomy clipping. Besides, a biodegradable magnesium titanium alloy biological stent was independently developed in this study, which was applied to endovascular interventional embolization in the group A. The hemodynamic model was established by using three-dimensional (3D) computer hemodynamic numerical simulation technology. Besides, the effects of all the patients before and after treatment were evaluated, in terms of blood pressure (BP), average wall shear stress (WSS) (AWSS), AWSS gradient (AWSSG), oscillatory shear index (OSI), aneurysm formation index (AFI), gradient oscillation number (GON), and intraoperative complication rate. Results: After 3 days of treatment, the BP, AWSS, and AWSSG of patients from the two groups were higher than those before treatment. The index values of the group A were greater markedly than the values of the group B (P < 0.05); the BP of the group A and the group B at the 0th day, 1st day, 3rd day, 5th day, and 7th day after treatment was 21±5.1 Versus 20.1±4.7, 22±4.8 Versus 21.1± 5.17, 26±6.2 Versus 22.31±5.21, 27±5.77 Versus 24.02±5.11, and 30±6.09 Versus 24.99±5.03, respectively; AWSSG values were 120±10.11 Versus 120.1±10.98, 130.1±10.36 Versus 123.3±11.06, 162.5±9.92 Versus 131.31±10.97, 171±8.13 Versus 155.02±8.36, and 200.1±7.22 Versus 180.01±8.98 in turn. GON and OSI were both decreased, and the values of various indexes in the group A were sharply lower than those of the group B (P < 0.05); the values of GON at the 0th day, 1st day, 3rd day, 5th day, and 7th day after treatment in the group A and the group B were 0.077±0.01 Versus 0.08±0.011, 0.07±0.012 Versus 0.073 ± 0.01, 0.051 ± 0.02 Versus 0.071 ± 0.011, 0.045 ± 0.01 Versus 0.069 ± 0.011, and 0.042 ± 0.012 Versus 0.063±0.013, respectively; OSI values were 4.8±0.51 Versus 4.9±0.52, 3.6±0.52 Versus 3.62±0.51, 2.82±0.51 Versus 3.1 ± 0.57, 1.9 ± 0.512 Versus 2.91 ± 0.51, and 0.5 ± 0.51 Versus 1.8 ± 0.501 in turn. By comparing the intraoperative complications and postoperative mortality risk score (MRS) of patients in the two groups, it was found that the incidence of intraoperative complications and postoperative MRS scores in the group A were lower steeply than those of the group B, suggesting that endovascular interventional embolization had a better effect on the treatment of intracranial aneurysms. Conclusion: Endovascular interventional embolization based on biodegradable magnesium alloy coated scaffold could better improve the distribution of shear stress on the vascular wall, stabilize vascular blood flow, and achieve better therapeutic effect for patients.

Comprehensive review of the recent advances in devices for endovascular treatment of complex brain aneurysms

The International Subarachnoid Aneurysm Trial (ISAT) showed superiority for endovascular treatment of ruptured aneurysms and technology has since moved on rapidly. Many approaches and technology now exist for the endovascular management of ruptured and unruptured intracranial aneurysms, which reflects their varied nature - there is no one-size-fits-all technique. We aim to provide an overview of the various classes of device and the major developments over the past decade. Coiling is the oldest of the technology and continues to demonstrate high levels of occlusion and acceptable risks, making it the default treatment choice, particularly in the acutely ruptured aneurysm setting. Advances on coiling include the use of adjuncts such as balloons, stents and fully retrievable temporary neck-bridging devices, which have facilitated the treatment of more complex aneurysms. Flow divertors have also revolutionised complex aneurysm treatment with small added risk in acute aneurysm treatment and seek to remodel the aneurysm-vessel interface without accessing the aneurysm sac. The latest development and most promising avenue appears to be intrasaccular flow disrupting devices like WEB, Contour and Neqstent that provide excellent opportunities to treat wide neck complex aneurysm with minimal mortality and morbidity and good occlusion rates and may in future replace a significant number of stent-assisted coiling too.

Endovascular embolization of wide-necked bifurcation aneurysms with the use of pCONus device: A systematic review and meta-analysis

BACKGROUND

The following study aimed to summarize the overall safety and efficacy of the pCONus device in the treatment of wide-necked bifurcation aneurysms.

MATERIAL AND METHODS

Major electronic medical databases were thoroughly searched to identify relevant studies. Data regarding the type of included studies, type of aneurysm and its location, treatment results measured in Raymond-Roy Occlusion Class (RROC) and its complications, as well as patients' neurological outcome at the discharge were extracted from the eligible studies and included in the meta-analysis. The subgroup analyses dependent on the aneurysm rupture status were also conducted.

RESULTS

A total of 8 studies (198 patients with 200 aneurysms) were included in this meta-analysis. The most common localization of the treated aneurysms was the middle cerebral artery with its pooled prevalence estimate (PPE) of 44.5%. Immediately after the procedure, RROC I (complete obliteration of the aneurysm) was observed in 46.8%, RROC II in 32.9%, while RROC III (residual aneurysm) in 20.3% of the patients. In a short-term follow-up, PPE of RROC I was 55.0%, RROC II 29.0%, and RROC III 16.1%. The PPE of intraprocedural complications was 17.3%, the most frequent were thromboembolic events, which were observed in 12.1% of all procedures. Poor neurological outcome at the discharge was noted with PPE of 9.6%.

CONCLUSIONS

The effectiveness and safety of wide-necked bifurcation aneurysm treatment utilizing the pCONus device is moderate. There is still a need for a consensus regarding the effective antiplatelet regimen in furtherance of diminishing the rate of thromboembolic events.

Recent advances in stent-assisted coiling of cerebral aneurysms

INTRODUCTION

Stent-assisted coiling (SAC) of intracranial aneurysms paved the way for endovascular coiling of wide-neck and bifurcation aneurysms, improving rates of aneurysm obliteration and recurrence. In this review, we provide a comprehensive review of the most recent advances related to stent-assisted coiling of intracranial aneurysm.

AREAS COVERED

The authors have made an attempt to cover the inception, applications, and limitations of SAC of intracranial aneurysms. Special focus is given to 1) the current and recently introduced SAC techniques, 2) most recent advances in device technology, and 3) outcome data for the discussed techniques and devices. The authors also discuss the potential future direction of SAC.

EXPERT OPINION

technical refinements in the field of SAC should continue to focus on device development and addressing the limitations of SAC, namely aneurysm recurrence and need of antiplatelet agents. Although the recurrence rate of SAC has not been shown to be inferior to flow diverters, the use of intrasaccular and intravascular flow diverters are likely to expand in the future at the expense of SAC.

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.

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.

Using the pCANvas neck-bridging device in treating a wide-necked aneurysm of the basilar tip

BACKGROUND AND IMPORTANCE

The endovascular treatment of recurrent wide-necked bifurcation aneurysms at the basilar tip remains very challenging. Many different techniques and devices have emerged in recent years as potential options but results remain less than controversial. The pCANvas is a relatively new device wielding neck-bridging properties with a haemodynamically active membrane acting as blood flow disrupter.

CLINICAL PRESENTATION

We present the clinical case of a patient in whom multiple endovascular and microsurgical attempts failed to achieve the definitive treatment of a large and wide-necked basilar tip aneurysm. The patient underwent successful endovascular implantation of the novel pCANvas device across the recurrent aneurysm neck. The device limited the blood flow to the anerysmal lumen and thus promoted faster thrombosis. Third month follow-up confirmed complete obliteration of the aneurysm.

CONCLUSION

The application of the pCANvas device offers a potential treatment option in difficult and recurrent aneurysms. The endovascular flow disruption is a relatively new feature aiming to create conditions for intraluminal thrombosis and is certainly promising for the treatment of complex bifurcation aneurysms.

Repeating enlargement, recanalisations, and subarachnoid haemorrhages after middle cerebral artery aneurysm embolisation using pCONus stent and coils - a case report

Purpose

Large and wide-necked bifurcation aneurysms remain technically challenging to treat by the endovascular approach. Several endovascular strategies have been established in recent years for treating wide-necked bifurcation aneurysms, such as balloon-assisted coiling, stent-assisted coiling, waffle cone technique (WCT), and intrasaccular flow disruptors.

Case report

A 64-year-old woman was diagnosed with three intracranial aneurysms of the right and left middle cerebral artery and right internal carotid artery. She was qualified for endovascular treatment of the left middle cerebral artery (LMCA) aneurysm because it posed the greatest risk of rupture. Due to complicated morphology, a pCONus stent and coils were chosen for treatment. Three months later the right middle cerebral artery aneurysm was embolised and the woman was scheduled for second-stage treatment of the LMCA aneurysm. One week before the planned admission the woman was diagnosed with subarachnoid haemorrhage (SAH) in the region of the previously treated LMCA aneurysm, and the second-stage treatment was conducted with a good result. The woman was discharged in improved condition. Three months later the woman was once again admitted with SAH – an enlarged LMCA aneurysm was observed and immediate third-stage embolisation was performed, but due to complications of SAH the woman eventually died.

Conclusions

On the basis of the presented case we would like to emphasise the importance of sufficient initial coil packing and frequent control of neck region of the aneurysm for the long-term stability and safety after pCONus-assisted coiling of intracranial aneurysms.

Treatment of Wide-Necked Bifurcation Aneurysms : Initial Results with the pCANvas Neck Bridging Device

Background

Recently, numerous devices dedicated to the treatment of wide-necked aneurysms have become available. We present our initial experience with the pCANvas device and present the technical success rate, clinical outcome and immediate angiographic occlusion rates.

Objective

We sought to determine the efficacy of flow with the pCANvas for the treatment of unruptured intracranial aneurysms.

Methods

We performed a retrospective review of our prospectively collected data to identify patients treated with the pCANvas device between February 2015 and February 2017. The patient demographics, aneurysm characteristics, immediate and delayed clinical and radiographic follow-up data were recorded.

Results

We identified 17 patients (13 female) treated only with the pCANvas device. The average age of the patients was 60.5 ± 13.3 years (range 25–75 years). The average dome width was 7.6 ± 3.2 mm (range 3–15.8 mm), dome height 7.1 ± 3.2 mm (range 3–12.9 mm) and neck width 5.4 ± 3.2 (range 3–16.3 mm). The average aspect ratio was 1.5 ± 0.8 (range 0.6–3.7). At the end of the procedure 15 aneurysms continued complete filling of the aneurysm (Raymond Roy Classification[RRC] 3) with 2 aneurysms showing only filling of the neck of the aneurysm (RRC 2). Early follow-up angiography was available for 16 patients and at this stage 11 aneurysms showed persistent and complete filling of the aneurysm (RRC 3), 5 aneurysms showed complete occlusion of the aneurysm (RRC 1) and 7 aneurysms underwent repeat treatment with coiling.

Conclusion

The early results on the use of the pCANvas are promising; however, longer term follow-up and larger studies are required.

Development of New Endovascular Devices for Aneurysm Treatment

Since the first use of the Guglielmi detachable coil system for cerebral aneurysm embolization in 1990, various endovascular methods have been developed to treat large numbers of aneurysms. The main strategic and technical modifications introduced to date include balloon-assisted coil embolization, stent-assisted coil embolization, flow diverters, and flow disrupters. The development and introduction of such devices have been so persistent and rapid that new devices are being approved worldwide even before the earlier ones become available in some countries. However, even if some patient populations may possibly benefit from earlier introduction of new devices, the approval authorities should balance the available evidence of the safety and effectiveness of novel devices. This review aims to provide an overview of the recent innovations in endovascular treatment of cerebral aneurysms and a brief review of market access policies and regulations for importing high-risk medical devices, such as those used for endovascular aneurysm management, which correspond to class III devices, as defined by the U.S. Food and Drug Administration. We focus on the current situation in Korea and compare it with that in other Asian countries, such as China and Japan.

Un-re-sheath-able Misaligned pCONus Device: Case Report of a Unique Complication

pCONus is a stent like endovascular device which aids in retention of coils within wide necked bifurcation aneurysms. It is retrievable even after complete deployment and is detached electrolytically. pCONus aided coiling of wide necked bifurcation aneurysms has a high technical success rate and a good safety profile. Different complications have been described in literature with the usage of pCONus. This case report describes a yet unreported complication of un-re-sheath-ability of a misaligned deployed pCONus device.

Misaligned pCONus Device: Case Report of a Unique Complication

pCONus is a stent-like endovascular device which aids in retention of coils within wide-necked bifurcation aneurysms. It is retrievable even after complete deployment and is detached electrolytically. The pCONus aided coiling of wide-necked bifurcation aneurysms has a high technical success rate and a good safety profile. Different complications have been described in literature with the usage of pCONus. This case report describes a unreported complication of inappropriately deployed pCONus device.

The Barrel stent: new treatment option for stent-assisted coiling of wide-necked bifurcation aneurysms—results of a single-center study

Purpose

The Barrel stent is a laser cut stent designed for stent-assisted coil embolization of wide-necked bifurcation or branch aneurysms with a single device, with the purpose of lowering the metal-to-artery ratio and its inherent risk of thromboembolic complications of multiple stents. We report our early experiences with this device in 17 patients in this retrospective single-center analysis.

Materials and methods

17 consecutive patients who underwent stent-assisted coil embolization of wide-necked bifurcation aneurysms with the Barrel stent were retrospectively identified. We analyzed the feasibility of successful deployment and post-treatment angiographic results. Adverse events, clinical outcome, and angiographic follow-up results were also analyzed.

Results

Aneurysms were located in the internal carotid artery (n=3), the middle cerebral artery (n=9), the anterior communicating artery (n=3), and the basilar artery (n=2). In the immediate post-treatment angiography, adequate occlusion (neck remnant or total occlusion) was observed in 16/17 (94.1%) of aneurysms. One patient experienced a transient ischemic attack. No permanent neurologic deficits were observed. 13/17 (76.5%) patients underwent short-term follow-up angiography after 3 months, all of which showed adequate occlusion of the aneurysm.

Conclusions

In this small retrospective single-center analysis we show that stent-assisted coiling with the Barrel stent is a safe and effective option for the endovascular treatment of intracranial wide-necked bifurcation aneurysms.

Use of the pCONus as an adjunct to coil embolization of acutely ruptured aneurysms

Introduction

Coil embolization of ruptured aneurysms has become the standard treatment in many situations. However, certain aneurysm morphologies pose technical difficulties and may require the use of adjunctive devices.

Objective

To present our experience with the pCONus, a new neck bridging device, as an adjunct to coil embolization for acutely ruptured aneurysms and discuss the technical success, angiographic and clinical outcomes.

Methods

We conducted a retrospective review of our database of prospectively collected data to identify all patients who presented with acute subarachnoid hemorrhage that required adjunctive treatment with the pCONus in the acute stage. We searched the database between April 2011 and April 2016.

Results

21 patients were identified (13 male, 8 female) with an average age of 54.6 years (range 31–73). 8 aneurysms were located at the basilar artery tip, 7 at the anterior communicating artery, 4 at the middle cerebral artery bifurcation, 1 pericallosal, and 1 basilar fenestration. 61.8% patients achieved modified Raymond–Roy classification I or II at immediate angiography, with 75% of patients having completely occluded aneurysms or stable appearance at initial follow-up. There were no repeat aneurysmal ruptures and two device-related complications (no permanent morbidity). Four patients in our cohort died.

Conclusions

Use of the pCONus is safe and effective in patients with acutely ruptured aneurysms and carries a high rate of technical success.