Surpass flow diverter in the treatment of intracranial aneurysms: a prospective multicenter study

In situ tissue engineering: endothelial growth patterns as a function of flow diverter design

Background

Vascular remodeling in response to implantation of a tissue engineering scaffold such as a flow diverter (FD) leads to the cure of intracranial aneurysms. We hypothesize that the vascular response is dependent on FD design, and CD34+ progenitor cells play an important role in the endothelialization of the implant.

Methods

Sixteen rabbit aneurysms were randomly treated with two different single-layer braided FDs made of cobalt–chrome alloys. The FD-48 and FD-72 devices had 48 and 72 wires, respectively. Aneurysm occlusion rate was assessed during the final digital subtraction angiogram at 10, 20, 30, and 60 days (n=2 per device per time point). Implanted vessels were analyzed with scanning electron microscopy for tissue coverage, endothelialization, and immuno-gold labeling for CD34+ cells.

Results

Complete aneurysm occlusion rates were similar between the devices; however, complete or near complete occlusion was more frequently observed in aneurysms with neck ≤4.2 mm (p=0.008). Total tissue coverage at 10 days over the surface of the FD-48 and FD-72 devices was 56.4±11.6% and 76.6±3.6%, respectively. Endothelial cell growth over the surface was time-dependent for the FD-72 device (Spearman's r=0.86, p=0.013) but not for the FD-48 device (Spearman's r=−0.59, p=0.094). The endothelialization score was marginally correlated with the distance from the aneurysm neck for the FD-48 device (Spearman's r=1, p=0.083) but not for the FD-72 device (Spearman's r=0.8, p=0.33). CD34+ cells were present along the entirety of both devices at all time points.

Conclusions

This study gives preliminary evidence that temporal and spatial endothelialization is dependent on FD design. Circulating CD34+ progenitor cells contribute to endothelialization throughout the healing process.

Flow Diversion for Ophthalmic Artery Aneurysms

Endovascular treatments of ophthalmic segment aneurysms are commonly used but visual outcomes remain a concern. We performed a retrospective review of patients with carotid-ophthalmic aneurysms treated with flow diversion from June 2009 to June 2015. The following outcomes were studied through chart review: visual outcomes, complications, postoperative stroke and intraparenchymal hemorrhage, and clinical outcomes. Angiographic outcomes were studied with angiography and MRA at 6 months, 1 year, and 3 years. We evaluated 50 carotid-ophthalmic aneurysms in 48 patients, among whom 44 patients with 46 aneurysms underwent treatment. The mean clinical follow-up was 29 ± 22 months (range, 0-65 months). There were no permanent adverse visual outcomes. There was 1 death because of late intraparenchymal hemorrhage (2.2%). Six-month angiography showed complete occlusion in 24 of 37 patients (64.9%), and 3-year angiography results showed occlusion in 24 of 25 patients (96%). In conclusion, flow diversion is a safe and effective treatment for carotid-ophthalmic aneurysms in carefully selected patients. The risk of adverse visual outcomes is low, and most aneurysms progress to complete occlusion.

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.

The pCONus Device in Treatment of Wide-necked Aneurysms : Technical and Midterm Clinical and Angiographic Results

PURPOSE

A variety of devices for treatment of wide-necked bifurcation aneurysms are emerging. Here we report our results using the new pCONus device with special emphasis on the morphological and anatomical requirements for successful implantation.

METHODS

In this study we treated 21 patients with 22 aneurysms by endovascular interventions. After providing informed consent, patients were included according to the following criteria: aneurysm dome to neck ratio <2 or neck diameter >4 mm. The primary end points for clinical safety were the absence of death, absence of major or minor stroke and absence of transient ischemic attack.

RESULTS

A total of 22 aneurysms in 21 patients were treated with pCONus-assisted coiling. In 19 patients harboring 20 aneurysms the implantation of the device was successful and these aneurysms showed an adequate occlusion after 6 months in 95 %. The complication rate was low (5 %) with one case of minor neurological stroke. Analysis of the data showed that the difference in aneurysm angulation between successful (mean 45°) and failed implantations (mean 71.5°) was highly significant.

CONCLUSION

Use of the pCONus device and coiling in wide-necked bifurcation aneurysms is safe and provides good occlusion rates but might be limited by the angulation between the aneurysm and the parent vessel.

Safety and efficacy of flow re-direction endoluminal device (FRED) in the treatment of cerebral aneurysms: a single center experience

BACKGROUND

Experience with the endovascular treatment of cerebral aneurysms by the Flow Re-Direction Endoluminal Device (FRED) is still limited. The aim of this study is to discuss the results and complications of this new flow diverter device (FDD).

METHODS

Between November 2013 and April 2015, 20 patients (15 female and five male) harboring 24 cerebral aneurysms were treated with FRED FDD in a single center.

RESULTS

Complete occlusion was obtained in 20/24 aneurysms (83 %) and partial occlusion in four (17 %). Intraprocedural technical complication occurred in one case (4 %) and post-procedural complications in three (12 %). None reported neurological deficits (mRS = 0). All FRED were patent at follow-up. No early or delayed aneurysm rupture, no subarachnoid (SAH) or intraparenchymal hemorrhage (IPH) no ischemic complications and no deaths occurred.

CONCLUSIONS

Endovascular treatment with FRED FDD is a safe treatment for unruptured cerebral aneurysms, resulting in a high rate of occlusion. The FRED is substantially equivalent to the other known FDDs, which show similar functions and technical profiles.

Mid-term and long-term follow-up of intracranial aneurysms treated by the p64 Flow Modulation Device: a multicenter experience

Background

Experience with the endovascular treatment of cerebral aneurysms using the p64 Flow Modulation Device is still limited. This study discusses the results and complications of this new flow diverter device.

Methods

40 patients (30 women, 10 men) with 50 cerebral aneurysms treated in six Italian neurointerventional centers with the p64 Flow Modulation Device between April 2013 and September 2015 were retrospectively reviewed.

Results

Complete occlusion was obtained in 44/50 aneurysms (88%) and partial occlusion in 3 (6%). In the other three aneurysms (6%), two cases of asymptomatic in-stent thrombosis and one intraprocedural occlusion of the parent vessel occurred. Technical complications were observed in eight procedures (16%). Permanent morbidity due to acute in-stent thrombosis and consequent ischemic stroke occurred in one patient (2.5%). No delayed aneurysm rupture, subarachnoid or intraparenchymal hemorrhage, or ischemic complications occurred and there were no deaths.

Conclusions

Endovascular treatment with the p64 Flow Modulation Device is a safe treatment for unruptured cerebral aneurysms, resulting in a high rate of occlusion. As with other flow diverter devices, we recommend this treatment mainly for large-necked aneurysms of the internal carotid artery siphon. However, endovascular treatment with the p64 device should also be encouraged in difficult cases such as aneurysms of the posterior circulation and beyond the circle of Willis.

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.

Endovascular treatment of posterior cerebral artery aneurysms: a single center's experience of 55 cases

OBJECTIVE Aneurysms of the posterior cerebral artery (PCA) are uncommon. To date, a limited number of studies have examined the outcomes of endovascular treatment for PCA aneurysms. The authors' aim in this study is to report their experience with the endovascular treatment of PCA aneurysms. METHODS Between January 2007 and December 2014, 55 patients with 59 PCA aneurysms were treated using the endovascular approach at the authors' institution. Twenty-three patients had 25 saccular aneurysms, and 32 patients had 34 fusiform/dissecting aneurysms. The endovascular modalities included the following: 1) selective occlusion of the aneurysm (n = 22); 2) complete occlusion of the aneurysm and the parent artery (n = 20); 3) parent artery occlusion (n = 6); 4) partial coiling of the aneurysm and the parent artery (n = 5); and 5) occlusion of the dissecting aneurysm sac (n = 2). RESULTS The immediate angiographic results included 45 complete occlusions (82%), 2 nearly complete occlusions (4%), and 8 incomplete occlusions (14%). The mean follow-up period of 21.8 months in 46 patients showed 37 stable results, 6 further thromboses, and 3 recurrences. The final results included 41 complete occlusions (89%), 2 nearly complete occlusions (4%), and 3 incomplete occlusions (7%). Procedure-related complications included the following: 1) rebleeding (n = 1); 2) infarction (n = 4); and 3) perforation (n = 1). There was 1 (1.8%) procedure-related death due to rebleeding, and 2 (3.6%) non-procedure-related deaths due to severe subarachnoid hemorrhage. Clinical outcomes were excellent (Glasgow Outcome Scale 5) in 47 of 49 patients at the long-term follow-up. CONCLUSIONS PCA aneurysms may be effectively treated by different endovascular approaches with favorable clinical and radiological outcomes. However, patients who present with severe SAH still have an overall poor prognosis. Partial coiling of the aneurysm and the parent artery is an attractive alternative treatment for patients who may not tolerate parent artery occlusion. Further study with a larger case series is necessary for validation of the durability and efficacy of this treatment.

Flow diverter treatment of posterior circulation aneurysms. A meta-analysis

Introduction

Treatment of complex anterior circulation aneurysms with flow diverters (FDs) has become common practice in neurovascular centers. However, this treatment method for posterior circulation aneurysms (PCAs) still remains controversial.

Methods

Through searches for reports on the treatment of PCAs with FDs, we conducted a systematic review of the literature on its clinical efficacy and safety using random-effect binomial meta-analysis.

Results

We included 14 studies, which reported on a total of 225 PCAs in 220 patients. Procedure-related good outcome rate was 79 % (95 % confidence interval (CI), 72–84), with significantly lower odds among patients with ruptured aneurysms and basilar artery aneurysms. Procedure-related mortality rate was 15 % (95 % CI 10–21), with significantly higher rates among patients with giant aneurysms and basilar artery aneurysms. The rate of complete aneurysm occlusion at 6-month digital subtraction angiography (DSA) was 84 %. Ischemic stroke rate was 11 %. Perforator infarction rate was 7 %. Postoperative subarachnoid hemorrhage (SAH) rate was 3 %. Intraparenchymal hemorrhage (IPH) rate was 4 %.

Conclusions

Flow diverter treatment of PCAs is an effective method, which provides a high rate of complete occlusion at 6-month DSA. However, compared with anterior circulation aneurysms, patients with PCAs are at significantly higher risk of mortality, ischemic stroke and perforator infarction. Our findings indicate that, in most clinical centers, flow diverter treatment of PCAs should be conducted in carefully selected patients with poor natural history and no optimal treatment strategy. For ruptured and giant basilar artery aneurysms, there is still no good treatment option.

Metal coverage ratio of pipeline embolization device for treatment of unruptured aneurysms: Reality check

BACKGROUND AND PURPOSE

The metal coverage ratio (MCR) of a flow diverter influences the intra-aneurysmal hemodynamics; a high MCR will occlude an aneurysm early, while a low MCR may delay aneurysm occlusion. The true MCR of a pipeline embolization device (PED) could be lower due to oversize, device deformation, or aneurysm location. In this study deviation of the true MCR from the nominal MCR is assessed and whether their difference affects aneurysm occlusion rate is determined.

METHODS

A total of 40 consecutive patients, each of them treated by one PED for their aneurysms at the internal carotid artery (ICA), were retrospectively analyzed. The DynaCT images of these deployed PEDs were used to determine their true dimensions and estimate three MCRs (local, mean, and nominal). These data were compared in two groups of patients who had different aneurysm outcomes at six months.

RESULTS

The difference in the local MCR between two groups is small, but statistically significant (24.5% vs 21.6%, p=05). The local MCR is consistently lower than the nominal MCRs (23.2% vs 30.2%, p<0.001); however, the difference between the mean and local MCRs is small (23.9% vs 23.2%).

CONCLUSIONS

An expectation that a PED can achieve a MCR of 30% may not be reasonable. Device oversize and deformation during deployment lower the local MCR by 5-7%. A lowered MCR affects the aneurysm occlusion rate at six months.

The Silk flow-diverter stent for endovascular treatment of intracranial aneurysms

Flow diverter (FD) stents represent a new endovascular technique developed for the treatment of complex intracranial aneurysms (wide neck, fusiform, large, and giant aneurysms) that are challenging for classic endovascular techniques such as coiling, balloon-assisted coiling and stent-assisted coiling. Low porosity, high metal coverage, and high pore density are the main properties of FD stents. These properties induce hemodynamic changes redirecting the blood flow away from the aneurysm and into the parent artery leading to gradual thrombosis of the aneurysm. FD stents also provide scaffolding for subsequent neoendothelial proliferation, and vessel wall remodeling. This is considered as a paradigm shift compared to prior endovascular methods, which predominantly aimed at providing treatment inside the aneurysmal sac. This paper describes in detail the first released FD stent, the Silk flow-diverter stent (Balt Extrusion, Montmorency, France), its mechanism of action and deployment technique. It reviews the pertinent literature regarding safety, efficacy and potential risks and complications associated with the use of this stent.

Endovascular treatment of cerebral aneurysms using flow-diverter devices: A systematic review

BACKGROUND

Flow-diverter devices (FDDs) are new-generation stents placed in the parent artery at the level of the aneurysm neck to disrupt the intra-aneurysmal flow thus favoring intra-aneurysmal thrombosis.

OBJECTIVE

The objective of this review article is to define the indication and results of the treatment of intracranial aneurysms by FDD, reviewing 18 studies of endovascular treatment by FDDs for a total of 1704 aneurysms in 1483 patients.

METHODS

The medical literature on FDDs for intracranial aneurysms was reviewed from 2009 to December 2014. The keywords used were: "intracranial aneurysms," "brain aneurysms," "flow diverter," "pipeline embolization device," "silk flow diverter," "surpass flow diverter" and "FRED flow diverter."

RESULTS

The use of these stents is advisable mainly for unruptured aneurysms, particularly those located at the internal carotid artery or vertebral and basilar arteries, for fusiform and dissecting aneurysms and for saccular aneurysms with large necks and low dome-to-neck ratio. The rate of aneurysm occlusion progressively increases during follow-up (81.5% overall rate in this review). The non-negligible rate of ischemic (mean 4.1%) and hemorrhagic (mean 2.9%) complications, the neurological morbidity (mean 3.5%) and the reported mortality (mean 3.4%) are the main limits of this technique.

CONCLUSION

Treatment with FDDs is a feasible and effective technique for unruptured aneurysms with complex anatomy (fusiform, dissecting, large neck, bifurcation with side branches) where coiling and clipping are difficult or impossible. Patient selection is very important to avoid complications and reduce the risk of morbidity and mortality. Further studies with longer follow-up are necessary to define the rate of complete occlusion.

Grading of Regional Apposition after Flow-Diverter Treatment (GRAFT): a comparative evaluation of VasoCT and intravascular OCT

Background

Poor vessel wall apposition of flow diverter (FD) stents poses risks for stroke-related complications when treating intracranial aneurysms, necessitating long-term surveillance imaging. To facilitate quantitative evaluation of deployed devices, a novel algorithm is presented that generates intuitive two-dimensional representations of wall apposition from either high-resolution contrast-enhanced cone-beam CT (VasoCT) or intravascular optical coherence tomography (OCT) images.

Methods

VasoCT and OCT images were obtained after FD implant (n=8 aneurysms) in an experimental sidewall aneurysm model in canines. Surface models of the vessel wall and FD device were extracted, and the distance between them was presented on a two-dimensional flattened map. Maps and cross-sections at potential locations of malapposition detected on VasoCT-based maps were compared. The performance of OCT-based apposition detection was evaluated on manually labeled cross-sections using logistic regression against a thresholded (≥0.25 mm) apposition measure.

Results

VasoCT and OCT acquisitions yielded similar Grading of Regional Apposition after Flow-Diverter Treatment (GRAFT) apposition maps. GRAFT maps from VasoCT highlighted 16 potential locations of malapposition, of which two were found to represent malapposed device struts. Logistic regression showed that OCT could detect malapposition with a sensitivity of 98% and a specificity of 81%.

Conclusions

GRAFT delivered quantitative and visually convenient representations of potential FD malapposition and occasional acute thrombus formation. A powerful combination for future neuroendovascular applications is foreseen with the superior resolution delivered by intravascular OCT.

Republished: Successful treatment of a giant pediatric fusiform basilar trunk aneurysm with surpass flow diverter

Fusiform aneurysms present a unique challenge to traditional microsurgical and endovascular treatment because of the lack of a discernible neck and the involvement of parent vessel. Flow diversion has increasingly become the treatment of choice for fusiform aneurysms in the anterior circulation, but its results in the posterior circulation are variable. We report successful treatment of a giant fusiform upper basilar trunk aneurysm with the Surpass flow diverter in an adolescent, and discuss the potential advantages of this emerging technology in the treatment of fusiform posterior circulation aneurysms.

Successful treatment of a giant pediatric fusiform basilar trunk aneurysm with surpass flow diverter

Fusiform aneurysms present a unique challenge to traditional microsurgical and endovascular treatment because of the lack of a discernible neck and the involvement of parent vessel. Flow diversion has increasingly become the treatment of choice for fusiform aneurysms in the anterior circulation, but its results in the posterior circulation are variable. We report successful treatment of a giant fusiform upper basilar trunk aneurysm with the Surpass flow diverter in an adolescent, and discuss the potential advantages of this emerging technology in the treatment of fusiform posterior circulation aneurysms.

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

BACKGROUND

Flow diversion is an important tool for treatment of cerebral aneurysms, particularly large and giant aneurysms. The Surpass flow diverter is a new system under evaluation in the USA.

OBJECTIVE

To report our initial experience of 20 cases with the Surpass flow diverter to demonstrate its basic properties, the required triaxial delivery platform, and the methodologies used to deploy it during treatment of large internal carotid artery (ICA) aneurysms

METHODS

Twenty patients with ICA aneurysms ≥10 mm with ≥4 mm neck treated as part of the Surpass IntraCranial Aneurysm Embolization System Pivotal Trial (the SCENT trial; Stryker) were included. Details of patient demographics, aneurysm characteristics, and technical procedures were collected.

RESULTS

Twenty patients (mean age 63.3±1.3 years; range 51-72) with 20 unruptured aneurysms (mean size 13.4±0.9 mm; range 10-21 mm) were treated. For proximal access, 60% of cases had aortic arch ≥grade II, 55% had significant cervical ICA tortuosity, and 60% had cavernous ICA ≥grade II. The Surpass device was implanted in 19/20 (95%) cases. Of 19 cases, a single device was used in 18 cases (95%) and 2 devices in only 1 case (5%). Balloon angioplasty was performed in 8/19 cases (42%). Complete aneurysm neck coverage and adequate vessel wall apposition was obtained in all 19 cases.

CONCLUSIONS

Surpass is a next-generation flow diverter with unique device-specific and delivery-specific features compared with clinically available endoluminal flow diverters. Our initial experience demonstrates a favorable technical profile in treatment of large and giant ICA aneurysms.

TRIAL REGISTRATION NUMBER

NCT01716117.

p64 Flow Modulation Device in the treatment of intracranial aneurysms: initial experience and technical aspects

BACKGROUND

Experience with the endovascular treatment of cerebral aneurysms by flow diverter devices (FDDs) is limited to four devices (Pipeline, Covidien; FRED, Microvention; Silk, Balt Extrusion; Surpass, Stryker), as reported in different studies.

OBJECTIVE

To describe the initial experience and the technical innovations of a new-generation FDD (p64 Flow Modulation Device, Phenox, Bochum, Germany).

METHODS

Between December 2014 and February 2015, six intracranial aneurysms in five patients (four women, one man; mean age 63 years) were treated with the p64 Flow Modulation Device.

RESULTS

Immediate post-treatment angiography showed reduced flow into all aneurysms. No long-term angiographic data are available. The device may be easily deployed and totally retrieved with a unique mechanical detachment. No periprocedural technical complications occurred. No early or delayed aneurysm rupture, no ischemic or hemorrhagic complications, and no neurological morbidity or death were seen.

CONCLUSIONS

Treatment of cerebral aneurysms with the p64 Flow Modulation Device is a safe procedure with no technical complications. The mechanical detachment and the 100% retrievability are significant advantages of this new device. However, large prospective studies with long-term clinical and angiographic follow-up are necessary to assess the role of the p64 in the endovascular treatment of intracranial aneurysms.