Flow diversion of large internal carotid artery aneurysms with the surpass device: impressions and technical nuance from the initial North American experience

Trends in the Age of Patients Treated for Unruptured Intracranial Aneurysms from 1990 to 2020

BACKGROUND

The decision for treatment for unruptured intracranial aneurysms (UIAs) is often difficult. Innovation in endovascular devices have improved the benefit-to-risk profile especially for elderly patients; however, the treatment guidelines from the past decade often recommend conservative management. It is unknown how these changes have affected the overall age of the patients selected for treatment. Herein, we aimed to study potential changes in the average age of the patients that are being treated over time.

METHODS

A systematic search of the literature was performed to identify all studies describing the age of the UIAs that were treated by any modality. Scatter diagrams with trend lines were used to plot the age of the patients treated over time and assess the presence of a potential significant trend via statistical correlation tests.

RESULTS

A total of 280 studies including 83,437 UIAs treated between 1987 and 2021 met all eligibility criteria and were entered in the analysis. Mean age of the patients was 55.5 years, and 70.7% were female. There was a significant increasing trend in the age of the treated patients over time (Spearman r: 0.250; P < 0.001), with a 1-year increase in the average age of the treated patients every 5 years since 1987.

CONCLUSIONS

The present study indicates that based on the treated UIA patient data published in the literature, older UIAs are being treated over time. This trend is likely driven by safer treatments while suggesting that re-evaluation of certain UIA treatment decision scores may be of great interest.

Dataset on flow diversion procedures performed with the Pipeline Embolization Device, Pipeline Flex, and Surpass Streamline for intracranial aneurysms

Flow diversion is an evolving endovascular modality for treating intracranial aneurysms. Although rare, serious adverse events following flow diversion may include ischemic stroke, intracranial hemorrhage, or delayed rupture of the treated aneurysm. This dataset describes 141 flow diversion procedures performed with the Pipeline Embolization Device, Pipeline Flex, or Surpass Streamline on 126 subjects with intracranial aneurysms [1]. The retrospective data were collected from electronic medical records at two large tertiary centers. Baseline patient data included age, sex, and medical comorbidities. The dataset also describes aneurysm characteristics including laterality, anatomic location, morphology, dome height, and neck width. In addition, digital subtraction images showing the internal carotid artery tortuosity were included for aneurysms in the anterior cerebral circulation [2]. Procedural data include case duration, radiation exposure, number of flow diverters deployed, and complications encountered during deployment. In addition, data related to the duration of hospitalization and postoperative adverse events are included. Finally, time to follow up and rates of total aneurysm obliteration at first and second postoperative visits are included. This data is propensity score matching are included. This data is presented as a starting point for future prospective comparisons in the safety and efficacy of flow diverters as more devices become approved and commercially available.

Pipeline Embolization Device and Pipeline Flex Versus Surpass Streamline Flow Diversion in Intracranial Aneurysms: A Retrospective Propensity Score-Matched Study

OBJECTIVE

To compare safety and efficacy profiles in aneurysms treated with Pipeline Embolization Device or Pipeline Flex versus Surpass Streamline flow diverters (FDs).

METHODS

Patients who underwent flow diversion for aneurysm treatment at 2 centers were included. Covariates comprised patient demographics, comorbidities, and aneurysm characteristics. Metrics included number of devices, adjuvant device use, case duration, and radiation exposure. Outcomes included periprocedural complications and radiographic results at follow-up. Propensity score-matched pairs were generated using demographic and aneurysm characteristics to verify the outcomes in equally sized groups.

RESULTS

The majority of 141 flow diversion procedures performed on 126 patients were in the anterior circulation (96%) and unruptured (93%). Operators experienced more complications placing Surpass FDs compared with Pipelines (18.2% vs. 3.1%, P = 0.005) but used fewer Surpass devices per case (1 device in all Surpass cases and range for Pipeline cases 1-7; P < 0.001). Ballooning was more frequent for Surpass (29.5% vs. 2.1%, P < 0.001). There were no differences in mortality (2.1% vs. 0, P = 1.00), intracranial hemorrhage (3.1% vs. 0, P = 0.551), or stroke (4.2% vs. 6.8%, P = 0.680). Rates of aneurysm obliteration at follow-up were similar. Propensity-matched pairs had no differences in FD deployment complications or perioperative events, yet the significant differences remained for adjuvant balloon use and number of FDs deployed.

CONCLUSIONS

While the devices demonstrated similar safety and efficacy profiles, deployment of the Surpass Streamline was more technically challenging than Pipeline Embolization Device or Pipeline Flex. Prospective cohort studies are needed to corroborate these findings.

Pipeline Embolization Stent for the Treatment of Giant Supraclinoid Aneurysms: A Case Series

Cerebrovascular aneurysms of the supraclinoid region are a technical challenge and can be particularly difficult to treat when greater than 25 mm in diameter. Such giant aneurysms can be approached with various skull-based and endovascular surgical techniques, and the advent of the Pipeline embolization stent presents a new treatment modality. Previously used for the treatment of small aneurysms, the Pipeline embolization device (PED) is a flow diverter device that has more recently been investigated in its use for the treatment of giant aneurysms with few studies to date published about its procedural outcomes. Here, we highlight the case of three patients (two elderly and one middle-aged) presenting symptomatically with giant supraclinoid aneurysms of the cavernous internal carotid artery (ICA) and posterior communicating artery treated with the Pipeline stent and monitored on follow-up visits. We further review the most current case reports and the two clinical trials to date investigating the utility of the Pipeline stent in the treatment of large and giant cerebral aneurysms, highlighting the emerging evidence of its efficacy and long-term patient outcomes. We report successful resolution of symptoms and radiographic evidence of aneurysm size reduction on all patient follow-ups and suggest the Pipeline embolization device as a novel technique that can be utilized for the treatment of giant cerebrovascular aneurysms with emerging evidence of immediate and long-term success.

Use of Surpass Streamline Flow Diverter for the Endovascular Treatment of Craniocervical Aneurysms: a Single-Institution Experience

INTRODUCTION

Flow diversion has revolutionized endovascular treatment for cerebral aneurysms. Surpass Streamline flow-diverter (SSFD) has shown promise for expanding flow diversion device options for aneurysm treatment. The SSFD differs from earlier stents by maintaining high porosity with increased pore density to ensure appropriate flow disruption. Given the delivery system's increased dimension options, and potential greater flow diverting properties, the SSFD is poised to extend the anatomic/pathologic reaches of flow diversion therapy.

METHODS

Data pertaining to SSFD-treated aneurysms were gathered retrospectively from 2019 to 2020. Collected information included aneurysm location, size, symptoms, complications, and occlusions rates at follow-up. Size was categorized as small (<10 mm), large (10-25 mm), and giant (>25 mm) according to SCENT trial criteria. Aneurysm occlusion on follow-up imaging was characterized by SMART grading with adequate occlusion defined as grades 3 and 4. Imaging was performed at time of treatment, six-month, and one-year follow-up.

RESULTS

42 SSFD-treated aneurysms were treated throughout the cerebrovascular system; 3 cervical, 4 posterior, and 35 intracranial anterior circulation. Complete occlusion rates at six months and one year were 48% and 57% with adequate occlusion achieved in 89.6% and 85.7% respectively. Rates of complete occlusion were higher for small aneurysms (69%) compared to large aneurysms (38%).

CONCLUSIONS

Our data suggests comparable complete occlusion rates compared to the SCENT trial (66.1% vs 57% in our center) and adequate occlusion rates. Similar occlusion rates to prior studies despite broadened inclusion criteria/diversity of aneurysms treated demonstrates favorable generalizability of flow-diverting technology to a wide array of aneurysmal pathology.

Twisting: Incidence and Risk Factors of an Intraprocedural Challenge Associated With Pipeline Flow Diversion of Cerebral Aneurysms

BACKGROUND

Pipeline Embolization Device (PED; Medtronic) "twisting" manifests with the appearance of a "figure 8" in perpendicular planes on digital subtraction angiography. This phenomenon has received little attention in the literature, requires technical precision to remediate, and has potential to cause ischemic stroke if not properly remediated.

OBJECTIVE

To report incidence, risk factors, and sequelae of PED twisting and to discuss techniques to remediate a PED twist.

METHODS

Case images were reviewed for instances of twisting from a prospectively-maintained, Institutional Review Board-approved cohort of patients undergoing flow diversion for cerebral aneurysm.

RESULTS

From August 2011 to December 2017, 999 PED flow diverting stents were attempted in 782 cases for 653 patients. A total of 25 PED twists were observed while treating 20 patients (2.50%, 25/999). Multivariate analysis revealed predictors of twisting to be: Large and giant aneurysms (odds ratio (OR) = 9.66, P = .005; OR = 27.47, P < .001), increased PED length (OR = 1.14, P < .001), and advanced patient age (OR = 1.07, P = .002). Twisted PEDs were able to be remediated 75% of the time, and procedural success was achieved in 90% of cases. PED twisting was not found to be a significant cause of major or minor complications. However, at long-term follow-up, there was a trend towards poor occlusion outcomes for the cases that encountered twisting.

CONCLUSION

Twisting is a rare event during PED deployment that was more likely to occur while treating large aneurysms with long devices in older patients. While twisting did not lead to major complications in this study, remediation can be challenging and may be associated with inferior occlusion outcomes.

Overview of Different Flow Diverters and Flow Dynamics

Over the past decade, flow diverter technology for endocranial aneurysms has seen rapid evolution, with the development of new devices quickly outpacing the clinical evidence base. However, flow diversion has not yet been directly compared to surgical aneurysm clipping or other endovascular procedures. The oldest and most well-studied device is the Pipeline Embolization Device (PED; Medtronic), recently transitioned to the Pipeline Flex (Medtronic), which still has sparse data regarding outcomes. To date, other flow diverting devices have not been shown to outperform the PED, although information comes primarily from retrospective studies with short follow-up, which are not always comparable. Because of this lack of high-quality outcome data, no reliable recommendations can be made for choosing among flow diversion devices yet. Moreover, the decision to proceed with flow diversion should be individualized to each patient. In this work, we wish to provide a comprehensive overview of the technical specifications of all flow diverter devices currently available, accompanied by a succinct description of the evidence base surrounding each device.

The Exchange-Free Technique: A Novel Technique for Enhancing Surpass Flow Diverter Placement

Background:

Following flow diverter placement, approximately 20% of intracranial aneurysms remain as residual aneurysms at 1 year. Device malapposition is a cause of residual aneurysms after flow diversion. We present a new and straightforward technique (exchange-free technique [EFT]) to enhance apposition of the surpass flow diverter (SFD), the only over-the-wire flow diverter currently available.

Materials and Methods:

We deployed laser-cut mini stents through the inner deployment catheter of the SFD. This maneuver was performed simply by withdrawing the micro-guidewire from its lumen and replacing it with a mini-stent (stents deliverable through microcatheters with inner diameter of 0.0165 inches), without a need to re-cross the deployed SFD or an exchange maneuver. All aneurysms in which this technique was utilized were retrospectively reviewed.

Results:

Twenty-eight patients (20 females) with 30 treated aneurysms were identified. The mean aneurysm diameter was 10.2 ± 6.6 mm. Technical success rate was 96.6% (29/30 aneurysms). There was no mortality or permanent morbidity related to the procedures. Except for the patient treated for an iatrogenic, surgery-related internal carotid artery pseudoaneurysm who died secondary to consequences of multiple surgeries, no cases of mortality or permanent morbidity were noted. Complete aneurysm occlusion rates were 78.2%, 82.1%, and 95.2% at 0–3, 3–6, and 9–12 months, respectively. None of the patients were re-treated.

Conclusion:

EFT is a simple and fast technique which was not associated with adverse effects in our series. The higher aneurysm obliteration rate obtained with EFT is probably the result of better wall apposition of the SFD.

Multimodal management of giant cerebral aneurysms: review of literature and case presentation

The pathophysiology of giant cerebral aneurysms renders them difficult to treat. Advances in technology have attempted to address any shortcomings associated with open surgery or endovascular therapies. Since the introduction of the flow diversion technique, the endovascular approach with flow diversion has become the first-line modality chosen to treat giant aneurysms. A subset of these giant aneurysms may persistent despite any treatment modality. Perhaps the best option for these recurrent and/or persistent giant aneurysms is to employ a multimodal approach-both surgical and endovascular-rather than any single technique to provide a curative result with favourable patient outcomes. This paper provides a review of the histopathology and treatment options for giant cerebral aneurysms. Additionally, an illustrative case is presented to highlight the unique challenges of a curative solution for giant cerebral aneurysms that persist despite initial treatment.

The Evolution of Flow-Diverting Stents for Cerebral Aneurysms; Historical Review, Modern Application, Complications, and Future Direction

In spite of the developing endovascular era, large (15–25 mm) and giant (>25 mm) wide-neck cerebral aneurysms remained technically challenging. Intracranial flow-diverting stents (FDS) were developed to address these challenges by targeting aneurysm hemodynamics to promote aneurysm occlusion. In 2011, the first FDS approved for use in the United States market. Shortly thereafter, the Pipeline of Uncoilable or Failed Aneurysms (PUFS) study was published demonstrating high efficacy and a similar complication profile to other intracranial stents. The initial FDA instructions for use (IFU) limited its use to patients 22 years old or older with wide-necked large or giant aneurysms of the internal carotid artery (ICA) from the petrous segment to superior hypophyseal artery/ophthalmic segment. Expanded IFU was tested in the Prospective Study on Embolization of Intracranial Aneurysms with PipelineTM Embolization Device (PREMIER) trial. With further post-approval clinical data, the United States FDA expanded the IFU to include patients with small or medium, wide-necked saccular or fusiform aneurysms from the petrous ICA to the ICA terminus. However, IFU is more restrictive in South Korea than in United States. Several systematic reviews and meta-analyses have sought to evaluate the overall efficacy of FDS for the treatment of cerebral aneurysms and consistently identify FDS as an effective technique for the treatment of aneurysms broadly with complication rates similar to other traditional techniques. A growing body of literature has demonstrated high efficacy of FDS for small aneurysms; distal artery aneurysms; non-saccular aneurysms posterior circulation aneurysms and complication rates similar to traditional techniques. In the short interval since the Pipeline Embolization Device was first introduced, FDS has been firmly entrenched as a powerful tool in the endovascular armamentarium. As new FDS are developed, established FDS are refined, and delivery systems are improved the uses for FDS will only expand further. Researchers continue to work to optimize the mechanical characteristics of the FDS themselves, aiming to optimize deploy ability and efficacy. With expanded use for small to medium aneurysms and posterior circulation aneurysms, FDS technology is firmly entrenched as a powerful tool to treat challenging aneurysms, both primarily and as an adjunct to coil embolization. With the aforementioned advances, the ease of FDS deployment will improve and complication rates will be further minimized. This will only further establish FDS deployment as a key strategy in the treatment of cerebral aneurysms.

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.

Introduction: History and Development of Flow Diverter Technology and Evolution

The introduction of flow diverter technology to the field of neurointervention has revolutionized the treatment of intracranial aneurysms. The therapy approach has shifted from intrasaccular aneurysm treatment to exclusion of the aneurysm from the blood circulation with remodeling of the parent artery. Previously, “difficult”-to-treat aneurysms including fusiform and blister aneurysms, but also aneurysms arising from a diseased vessel segment, can now be safely and permanently treated with flow diverters.

 A little over a decade ago, after extensive bench testing and refinement of the flow diverter concept, the device was eventually available for clinical use and today it has become a standard treatment for intracranial aneurysms. Currently, United States Food and Drug Administration (FDA)-approved flow diverters are the Pipeline Embolization Device (Medtronic) and the Surpass Streamline Flow Diverter (Stryker).

 The devices can either be delivered or deployed via a standard femoral artery approach or a radial artery approach. Other considerations for catheter setup and device deployment strategies depending on aneurysm location or vessel anatomy are described.

Flow Diversion for Intracranial Aneurysm Treatment: Trials Involving Flow Diverters and Long-Term Outcomes

Flow diverters (FDs) have changed the management of brain aneurysms; not only for complex aneurysms (giant, fusiform and blister) refractory to conventional therapies, but also for unruptured lesions previously managed by traditional surgical or coil-based endovascular methods. Since 2011 when the PipelineTM Embolization Device (Medtronic) was cleared by the Food and Drug Administration for adults with large or giant wide-neck intracranial aneurysms of the internal carotid artery proximal to the posterior communicating segment, the role of flow diversion for aneurysm treatment has expanded—supported by favorably low complication and high cure rates compared with alternative treatments. Here we review the key clinical trials and the long term outcomes that have demonstrated safety and efficacy of minimized porosity endoluminal devices in the treatment of cerebral aneurysms.

Flow diversion treatment of aneurysms of the complex region of the anterior communicating artery: which stent placement strategy should 'I' use? A single center experience

BACKGROUND

Aneurysms of the anterior communicating artery (ACoA) are difficult to treat with coiling or clipping because of the anatomical variation in this region. Flow diversion represents a feasible treatment, but no consensus exists as to which stent deployment technique is more suitable.

METHODS

All patients with ACoA aneurysms treated with flow diverters between April 2014 and November 2018 were retrospectively analyzed. Aneurysm characteristics, follow-up results, and clinical outcome data were recorded, and a new classification comparing the diameters of both A1 segments is proposed: H1=same diameters; H2=<50% difference in diameters; H3= ≥50% difference; and Y=no A1 segment.

RESULTS

We analyzed 30 procedures in 30 patients with ACoA aneurysms, including 16 ruptured aneurysms treated with coiling embolization and 4 previously unruptured aneurysms (two Medina and two Woven EndoBridge devices). Adequate aneurysm occlusion occurred in 86.9%; one patient (3.3%) experienced symptomatic ischemic stroke. The global thromboembolic complications for each group were 17.6% (H1), 25% (H2), and 60% (H3).

CONCLUSION

Flow diversion treatment in this region is safe, feasible, and effective. The most suitable anatomical configuration for flow diverter treatment seems to be the H1 configuration where the 'I technique' is suitable (from an A1 segment to the ipsilateral A2). There is a tendency that the H3 configuration is not a good indication for flow diverter treatment. However, further studies are needed to evaluate the feasibility of this anatomical classification and the reproducibility of our findings.

On Flow Diversion: The Changing Landscape of Intracerebral Aneurysm Management

Uptake of flow-diverting technology is rapidly outpacing the availability of clinical evidence. Most current usage is off-label, and the endovascular community is nearer the beginning than the end of the learning curve, given the number of devices in development. A comprehensive overview of technical specifications alongside key outcome data is essential both for clinical decision-making and to direct further investigations. Most-studied has been the Pipeline Embolization Device, which has undergone a transition to the Pipeline Flex for which outcome data are sparse or heterogeneous. Alternative endoluminal devices do not appear to be outperforming the Pipeline Embolization Device to date, though prospective studies and long-term data mostly are lacking, and between-study comparisons must be treated with caution. Nominal technical specifications may be unrelated to in situ performance, emphasizing the importance of correct radiologic sizing and device placement. Devices designed specifically for bifurcation aneurysms also lack long-term outcome data or have only recently become available for clinical use. There are no major studies directly comparing a flow-diverting device with standard coiling or microsurgical clipping. Data on flow-diverting stents are too limited in terms of long-term outcomes to reliably inform clinical decision-making. The best available evidence supports using a single endoluminal device for most indications. Recommendations on the suitability and choice of a device for bifurcation or ruptured aneurysms or for anatomically complex lesions cannot be made on the basis of current evidence. The appropriateness of flow-diverting treatment must be decided on a case-by-case basis, considering experience and the relative risks against standard approaches or observation.

Endovascular Metal Devices for the Treatment of Cerebrovascular Diseases

Cerebrovascular disease involves various medical disorders that obstruct brain blood vessels or deteriorate cerebral circulation, resulting in ischemic or hemorrhagic stroke. Nowadays, platinum coils with or without biological modification have become routine embolization devices to reduce the risk of cerebral aneurysm bleeding. Additionally, many intracranial stents, flow diverters, and stent retrievers have been invented with uniquely designed structures. To accelerate the translation of these devices into clinical usage, an in-depth understanding of the mechanical and material performance of these metal-based devices is critical. However, considering the more distal location and tortuous anatomic characteristics of cerebral arteries, present devices still risk failing to arrive at target lesions. Consequently, more flexible endovascular devices and novel designs are under urgent demand to overcome the deficiencies of existing devices. Herein, the pros and cons of the current structural designs are discussed when these devices are applied to the treatment of diseases ranging broadly from hemorrhages to ischemic strokes, in order to encourage further development of such kind of devices and investigation of their use in the clinic. Moreover, novel biodegradable materials and drug elution techniques, and the design, safety, and efficacy of personalized devices for further clinical applications in cerebral vasculature are discussed.

Surpass Flow Diverter in the Treatment of Ruptured Intracranial Aneurysms-A Single-Center Experience

BACKGROUND

Use of a Surpass flow diverter (FD) device in the treatment of acutely ruptured aneurysm has not been well studied and reported in the literature.

METHODS

We retrospectively reviewed patients with subarachnoid hemorrhage who were treated by Surpass FD placement at our hospital between June 2016 and March 2018. Detailed analysis of medical records was performed to obtain patient age, gender, clinical history, Hunt and Hess grade, Fisher grade, results of radiographic and procedural details including technical success and complication, clinical outcome, and follow-up angiographic results.

RESULTS

Our search identified 16 patients with 16 aneurysms who were treated with Surpass FD, of which 13 aneurysms (81%) were in the anterior circulation and 3 (19%) were in the posterior circulation. Aneurysm size ranged from 1.1 to 16 mm, with a mean of 4 mm. The mean delay between subarachnoid hemorrhage and endovascular treatment was 5 days (range, 3-20 days). Only 1 Surpass FD was used in each patient, ranging in size from 3 × 25 mm to 4 × 50 mm. Fifteen patients (94%) achieved favorable clinical outcome (modified Rankin Scale score 0-1) at 3 months. One patient died of invasive fungal infection. Angiographic follow-up results were assessed by O'Kelly-Marotta grading scale in 15 surviving patients and showed a grade D result (no filling) in 13/15 aneurysms (87%) at 3 and 6 months.

CONCLUSIONS

A Surpass FD device is a feasible option for the treatment of ruptured intracranial aneurysms that are difficult to treat by conventional clipping and coiling; however, larger and comparative studies with long-term follow-up are needed to confirm its safety and efficacy.

Usefulness of Cone Beam Intra-Arterial CTA for Evaluation of Flow Diverters: A Practical Approach for Daily Use

Cone beam computed tomography (CBCT), initially used for evaluation of intraprocedural complications such as hemorrhage, has evolved to provide details of implanted devices such as flow diverters. The study aim is to present our experience in using CBCT with intra-arterial injection and provide a step-by-step approach for postprocessing in a practical protocol for daily use. IRB approval was obtained, and the neurointerventional database was retrospectively reviewed from July 2012 to June 2017. Patients who underwent cone beam intra-arterial CT angiography for evaluation of implanted flow diverter devices were reviewed. Patient demographics, aneurysm location (internal carotid artery [ICA]-cavernous, ICA-paraclinoid, and ICA-distal; middle cerebral artery [MCA], anterior cerebral artery [ACA]-acom, ACA-pericallosal, vertebral artery [VA]), type (saccular, dissecting fusiform, or blister) and size, device, injection technique (contrast dilution, rate, and volume), and reconstruction protocol were recorded. Acquired images were postprocessed using a Philips Xtravision workstation. Eighty patients (63 women and 17 men) met the inclusion criteria of our study. Age range was 25-80 years old. Treated aneurysms were located in the ICA-paraclinoid in 48 cases (60%), ICA-distal in 12 cases, ICA-cavernous in 8 cases, MCA in 4 cases, VA in 4 cases, ACA-acom in 2 cases, ACA-pericallosal in 2 cases; 69 were saccular, 8 fusiform, and 3 ruptured blister aneurysms. There were 52 small, 20 large, and 8 giant aneurysms. Pipeline (Medtronic, MN, USA) was the predominant device used in 77 procedures. Two injection techniques were used: 2.5 mL/s for a total volume of 55 mL with a 2-s imaging delay or 3 mL/s for a total volume of 70 mL with a 3-s imaging delay; contrast (Ioxilan 300 mgI/mL) dilution was 10-20% in all cases. The device's landing zones, conformability, presence of deformities, and wall apposition were successfully visualized in all cases. Metal artifact reduction program was applied in 9 coiled aneurysms, and this was satisfactory as well.

Surpass Streamline Flow-Diverter Embolization Device for Treatment of Iatrogenic and Traumatic Internal Carotid Artery Injuries

Iatrogenic and traumatic cerebral internal carotid artery injuries are uncommon but potentially lethal complications. Direct surgical repair of ICA injuries may be difficult in an acute setting. However, endovascular treatment with a flow-diverter embolization device is a feasible alternative technique that we experienced. In this clinical report, we describe demographic data, radiographic images, lesion characteristics, endovascular procedure notes, postprocedural hospital course, and follow-up digital subtraction angiography of 5 patients. At least 6-month follow-up was available in all patients without occurrence of rebleeding and other complications.

Intermediate catheter placement distal to the cerebral aneurysm during flow diversion embolization with the Surpass device

Purpose

We present the preliminary angiographic and clinical results of the combined utilization of an AXS Catalyst 5 (Cat5) distal access catheter and a Surpass flow diverter (SFD) for the endovascular treatment of intracranial aneurysms.

Materials and methods

Interventional neuroradiology case records were evaluated retrospectively to identify patients treated with an SFD in combination with Cat5. Demographic data, technical success, location of the catheter tip, aneurysm occlusion rate, and procedure-related morbidity and mortality were noted.

Results

The analysis yielded 24 patients with 25 aneurysms with a mean age of 52.3±19.7 years. The mean aneurysm diameter was 15.7±8.8 mm. Twenty-one were anterior circulation (seven supraclinoid, one middle cerebral, one anterior choroidal and 12 petrocavernous) and four were posterior circulation (three basilar tip, one posterior inferior cerebellar) aneurysms. Only two of these aneurysms were re-treatments for recurrences. For SFD deployment, the distal tip of Cat5 was placed intradurally and at, or distal to, M1 segment in 88% and 48% of patients, respectively. Aneurysms were bypassed with Cat5 in 80% of the procedures. In one patient, flow diversion was abandoned totally due to arterial tortuosity. With the exclusion of this patient, the technical success rate was 91.7%. There was no permanent procedure-related morbidity or mortality. Of the 22 aneurysms treated successfully with the Surpass device, 20 had imaging follow-up at 6.3±3.8 months and 95% were totally occluded.

Conclusion

The Cat5 catheter, which was manufactured for the navigation of large-bore stent-like devices, is a useful adjunct to the Surpass device and allowed us to deploy the device safely.

Update on flow diverters for the endovascular management of cerebral aneurysms

Flow diversion has become a well-accepted option for the treatment of cerebral aneurysms. Given the significant treatment effect of flow diverters, numerous options have emerged since the initial Pipeline embolization device studies. In this review, the authors describe the available flow diverters, both endoluminal and intrasaccular, addressing nuances of device design and function and presenting data on complications and outcomes, where available. They also discuss possible future directions of flow diversion.

47 Consecutive Cases of Pipeline Flex Flow Diversion Utilizing a Novel Large-Bore Intracranial Intermediate Catheter: Nuances and Institutional Experience with the Syphontrak

Background

The increasing complexity of modern neurointerventions has necessitated a shift in intracranial access techniques towards more robust distal support platforms. Here we present our experience with the Syphontrak Support Catheter (Codman Neuro, Raynham, MA, USA) in the triaxial platform for the implantation of the second-generation Pipeline Flex embolization device (PED Flex; Medtronic Neurovascular, Irvine, CA, USA).

Methods

We retrospectively identified patients who underwent PED Flex treatment utilizing the Syphontrak at a single institution. The procedural data collected included parent artery tortuosity, patient demographics, aneurysm characteristics, other equipment utilized, and catheter-related complications.

Results

A total of 47 consecutive aneurysm flow diversions were successfully performed using the Syphontrak. The patients' age ranged from 25 to 80 years (mean 57.3 ± 11.6) and 85% were women. The average aneurysm size was 4.8 ± 2.7 mm (range 2-14). All cases were in the anterior circulation, with 6 (12%) aneurysms located beyond the internal carotid artery termination. Significant cervical carotid tortuosity was present in 23% (11/47) of the cases and moderate-to-severe cavernous tortuosity (cavernous grade ≥2) in 51% (24/47) of the cases. The mean fluoroscopy time was 36.6 ± 14.8 min. In 12/47 cases (26%), vasospasm prophylaxis with intra-arterial verapamil infusion was performed. The Syphontrak was tracked to the intended distal position in all cases, with a 100% technical success of PED Flex implantation. Forty-six (98%) of the 47 patients were discharged home after an average length of stay of 1.38 days. No iatrogenic catheter-related vessel injury occurred. Transient, minor neurological morbidity occurred in 3 cases (6%) and 1 patient had a minor ischemic event (NIHSS score < 4) in the periprocedural period.

Conclusion

The Syphontrak is a new large-bore, multi-durometer intermediate catheter (IC) designed for use in modern neurointerventional procedures. We have shown its utility in 47 successful cases of PED Flex flow diversion of a wide range of complexity. The IC provides robust and atraumatic distal intracranial access while also providing an enhanced image quality with its large 0.060″ inner diameter.

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.

Use of a next-generation multi-durometer long guide sheath for triaxial access in flow diversion: experience in 95 consecutive cases

BACKGROUND

Intracranial access techniques in modern neurointerventions have shifted towards more robust access platforms. The long guide sheath is one of the building blocks of triaxial systems used in intracranial embolizations. Here we present our experience with the AXS Infinity LS long sheath in the triaxial platform for the implantation of the Pipeline embolization device (PED).

METHODS

We retrospectively identified patients who underwent PED Flex treatment with the AXS Infinity LS at a single institution. Procedural data collected included parent artery tortuosity, patient demographics, vasodilator use, aneurysm characteristics, equipment utilized, and catheter-related complications.

RESULTS

A total of 95 cases were completed using the AXS Infinity LS for the triaxial platform foundation in PED Flex treatment of cerebral aneurysms. Mean patient age was 56.2±12.2 years (range 21-86). Average aneurysm size was 6.9±6.2 mm (range 1-38). There were 89 anterior circulation cases (94%) and 6 posterior circulation cases (6%). Significant cervical ICA tortuosity was present in 11/89 (12%) and moderate to severe cavernous ICA tortuosity was present in 29/89 (33%). Mean fluoroscopy time was 40.0±19.8 min. In 14/95 cases (15%), vasospasm prophylaxis or treatment with intra-arterial verapamil infusion was performed. Catheter access-related complications included asymptomatic iatrogenic dissection in one case (1%) from the distal intracranial catheter and groin hematoma in one case (1%). No parent vessel wall abnormalities were visualized in the region of the Infinity long sheath on final control angiography in all 95 cases.

CONCLUSION

The AXS Infinity LS is the newest long guide sheath available for modern neurointerventional procedures. We have shown its utility in augmenting the triaxial access platform in PED Flex cases by providing enhanced distal tip trackability with added support in the aortic arch and proximal great vessels.

Ultrasound for the evaluation of stenosis after flow diversion

Background and purpose

Flow diversion is a relatively new strategy used to treat complex cerebral aneurysms. The optimal method for radiographic follow-up of patients treated with flow diverters has not been established. The rate and clinical implications of in-stent stenosis for these devices is unclear. We evaluate the use of transcranial Doppler ultrasound (TCD) for follow-up of in-stent stenosis.

Materials and methods

We analyzed 28 patients treated with the Pipeline embolization device (PED) over the course of 42 months from January 2009 to June 2012. Standard conventional cerebral angiograms were performed in all patients. TCD studies were available in 23 patients.

Results

Angiographic and TCD results were compared and found to correlate well.

Conclusions

TCD is a potentially useful adjunct for evaluating in-stent stenosis after flow diversion.

Cerebral aneurysm treatment: modern neurovascular techniques

Endovascular treatment of cerebral aneurysm continues to evolve with the development of new technologies. This review provides an overview of the recent major innovations in the neurointerventional space in recent years.

Evaluation of Pipeline Flex delivery system for the treatment of unruptured aneurysms

INTRODUCTION

Refinements in endovascular technology have revolutionized the treatment of intracranial aneurysms (IAs) with the development of flow-diversion technology. The first generation of the Pipelin Embolization Device (PED) has demonstrated its safety and efficacy. However, the deployment technique was a difficult task that often led to complex maneuvers. The Pipeline Flex Embolization Device (PED Flex) is the second generation and its introduction has arrived with high expectations due to a completely redesigned delivery system that intends to overcome deployment difficulties seen in the previous generation. Areas covered: Preclinical studies, mechanism of action of flow-diverters, technical aspects and deployment system of the PED Flex, and clinical outcomes with both PED generations. Expert commentary: Flow diversion has allowed us to treat lesions that would be otherwise challenging for surgical clipping or unsuitable for other endosaccular strategies. Although the experience with PED Flex is limited, initial results suggest its safety and short-term efficacy.

Flow Diversion for Intracranial Aneurysm Management: A New Standard of Care

Endovascular treatment of intracranial aneurysms with complex morphologies such as giant, wide-necked, or fusiform aneurysms is challenging. Stent-assisted coiling and balloon-assisted coiling are alternative techniques to treat such complex aneurysms, but studies have shown less-than-expected efficacy, as suggested by their high rate of recanalization. The management of complex aneurysms via microsurgery or conventional neuroendovascular strategies has traditionally been poor. However, over the last few years, flow-diverting stents (FDS) have revolutionized the treatment of such aneurysms. FDS are implanted within the parent artery rather than the aneurysm sac. By modifying intra-aneurysmal and parent-vessel flow dynamics at the aneurysm/parent vessel interface, FDS trigger a cascade of gradual intra-aneurysmal thrombosis. As endothelialization of the FDS is complete, the parent vessel reconstructs while preserving the patency of normal perforators and side branch vessels. As with any intervention, the practice and application of flow-diversion technology is inherent, with risks that include vessel rupture or perforation, in-stent thrombosis, perforator occlusion, procedural and delayed hemorrhages, and perianeurysmal edema. Herein, we review the devices, their mechanisms of actions, clinical applications, complications, and ongoing studies.