The Society for Vascular Surgery clinical practice guidelines on the management of visceral aneurysms.

Minimally invasive transcatheter embolization is a common nonsurgical procedure in interventional radiology used for the deliberate occlusion of blood vessels for the treatment of diseased or injured vasculature. A wide variety of embolic agents including metallic coils, calibrated microspheres, and liquids are available for clinical practice. Additionally, advances in biomaterials, such as shape-memory foams, biodegradable polymers, and in situ gelling solutions have led to the development of novel preclinical embolic agents. The aim here is to provide a comprehensive overview of current and emerging technologies in endovascular embolization with respect to devices, materials, mechanisms, and design guidelines. Limitations and challenges in embolic materials are also discussed to promote advancement in the field.

Advances in Biomaterials and Technologies for Vascular Embolization

Background and purpose BRANCH (wide-neck bifurcation aneurysms of the middle cerebral artery and basilar apex treated by endovascular techniques) is a multicentre, retrospective study comparing core lab evaluation of angiographic outcomes with self-reported outcomes. Materials and methods Consecutive patients were enrolled from 10 US centres, aged between 18 and 85 with unruptured wide-neck middle cerebral artery (MCA) or basilar apex aneurysms treated endovascularly. Patient demographics, aneurysm morphology, procedural information, mortality and morbidity data and core lab and self-reported modified Raymond Roy (RR) outcomes were obtained. Results 115 patients met inclusion criteria. Intervention-related mortality and significant morbidity rates were 1.7% (2/115) and 5.8% (6/103) respectively. Core lab adjudicated RR1 and 2 occlusion rates at follow-up were 30.6% and 32.4% respectively. The retreatment rate within the follow-up window was 10/115 (8.7%) and in stent stenosis at follow-up was 5/63 (7.9%). Self-reporting shows a statistically significant direction to angiographic RR one outcomes at follow-up compared with core lab evaluation, with OR 1.75 (95% CI 1.08 to 2.83). Conclusion Endovascular treatment of wide-neck MCA and basilar apex aneurysms resulted in a core lab adjudicated RR1 occlusion rate of 30.6%. Self-reported results at follow-up favour better angiographic outcomes, with OR 1.75 (95% CI 1.08 to 2.83). These data demonstrate the need for novel endovascular devices specifically designed to treat complex intracranial aneurysms, as well as the importance of core lab adjudication in assessing outcomes in such a trial.

https://jnis.bmj.com/content/neurintsurg/11/1/31.full.pdf

Wide-neck bifurcation aneurysms of the middle cerebral artery and basilar apex treated by endovascular techniques: a multicentre, core lab adjudicated study evaluating safety and durability of occlusion (BRANCH).

Objective To assess the clinical safety and efficacy of the Atlas microstent in stent-assisted coil embolization of wide-necked intracranial aneurysms. Methods Single-center observational study in 36 patients (24 female, 12 male, mean age 56 years) with 37 aneurysms for the endovascular treatment of wide-necked aneurysms. After giving informed consent, patients were included according to the following criteria: aneurysm dome-to-neck ratio  4 mm, and a parent vessel diameter of ≤4.5 mm. Primary endpoint for clinical safety was absence of death, absence of major or minor stroke, and absence of transient ischemic attack. Primary endpoint for treatment efficacy was complete angiographic occlusion according to the Raymond-Roy occlusion classification (RROC) immediately after the procedure. Results In 36/37 (97%) cases, the primary endpoint of safety was reached, one patient had a transitory ischemic attack which completely resolved until discharge. In 31/37 (84%) cases, complete occlusion (RROC 1) was reached, and in 6/36 (17%), a residual neck remained (RROC 2). A sequential approach (first stent, then coiling through the same catheter) was used in 21 cases; the other 16 were treated with the jailing technique. Deployment was technically successful in all cases. Follow-up at a median of 6.1 months was available for 29/37 (78%) aneurysms and showed complete occlusion in 27/29 aneurysms (93%) and a neck remnant in 2 cases (7%). Conclusion Deployment of the Neuroform Atlas microstent is a safe and effective method for the treatment of intracranial wide-necked aneurysms.

https://jnis.bmj.com/content/neurintsurg/10/12/1192.full.pdf

The Neuroform Atlas stent to assist coil embolization of intracranial aneurysms: a multicentre experience.

Advances in the management and endovascular treatment of intracranial aneurysms are progressing at a tremendous rate. Developments in novel imaging technology may improve diagnosis, risk stratification, treatment planning, intraprocedural assessment, and follow-up evaluation. Evolution of devices, including microwires, microcatheters, balloons, stents, and novel scaffolding devices, has greatly expanded the potential to treat difficult aneurysms. Although developments in technology have greatly improved the efficiency and efficacy of treatment of neurovascular disorders, novel devices do not always improve outcomes and may be associated with unique complications. As such, it is paramount to have an in-depth understanding of new devices and the implications of their introduction into clinical practice. This review provides an update on developments in endovascular treatment of intracranial aneurysms.

https://jnis.bmj.com/content/neurintsurg/8/2/135.full.pdf

Technology developments in endovascular treatment of intracranial aneurysms

Background The Raymond–Roy Occlusion Classification (RROC) is the standard for evaluating coiled aneurysms (Class I: complete obliteration; Class II: residual neck; Class III: residual aneurysm), but not all Class III aneurysms behave the same over time. Methods This is a retrospective review of 370 patients with 390 intracranial aneurysms treated with coil embolization. A Modified Raymond–Roy Classification (MRRC), in which Class IIIa designates contrast within the coil interstices and Class IIIb contrast along the aneurysm wall, was applied retrospectively. Results Class IIIa aneurysms were more likely to improve to Class I or II than Class IIIb aneurysms (83.34% vs 14.89%, p Conclusions We propose the MRRC to further differentiate Class III aneurysms into those likely to progress to complete occlusion and those likely to remain incompletely occluded or to worsen. The MRRC has the potential to expand the definition of adequate coil embolization, possibly decrease procedural risk, and help endovascular neurosurgeons predict which patients need closer angiographic follow-up. These findings need to be validated in a prospective study with independent blinded angiographic grading.

https://jnis.bmj.com/content/neurintsurg/7/7/496.full.pdf

An update to the Raymond–Roy Occlusion Classification of intracranial aneurysms treated with coil embolization

Background and purpose The Penumbra Coil 400 System (PC 400) is the newly introduced platinum coil system designed specifically to enhance filling efficiency by increasing coil diameter. Our goal was to study the packing and treatment advantage of the PC 4009s unique geometric configuration compared with conventional coils (controls). Materials and methods 16 aneurysms embolized with the PC 400 in 2011 were compared with 79 equally matched aneurysms embolized with conventional coils from 2004 to 2011. Primary outcomes assessed were acute packing density, embolization time, and the number of coils required for aneurysm occlusion. Results Aneurysm embolization with the PC 400 achieved a higher packing density (36.8% vs 28.1%; p Conclusions Compared with conventional coils, the PC 400 is more efficient in the embolization of cerebral aneurysms, achieving greater packing density with fewer coils and less time without compromising safety.

Initial experience with Penumbra Coil 400 versus standard coils in embolization of cerebral aneurysms: a retrospective review

Background The initial experience with the large diameter Penumbra Coil 400 (PC400) system has been positive regarding safety, efficacy, improved packing density and cost effectiveness, but follow-up data are limited. Methods This is a single-center retrospective review of 76 aneurysms treated with PC400 coils compared with 301 aneurysms treated with a variety of different bare platinum and bioactively coated coils. Atypical and giant aneurysms were excluded as well as those that had undergone previous treatment. Occlusion classification was determined immediately after the procedure and at short-term follow-up. Results Compared with controls, in the PC400 group fewer coils were used (3.53 vs 5.44, p Conclusions Large diameter PC400 coils can be used to safely treat cerebral aneurysms with fewer coils, decreased procedure time and increased packing density compared with standard coils. The early angiographic outcome is similar to that achieved with standard coils.

https://jnis.bmj.com/content/neurintsurg/7/2/126.full.pdf

Analysis of early angiographic outcome using unique large diameter coils in comparison with standard coils in the embolization of cerebral aneurysms: a retrospective review

Purpose The Penumbra Coil 400 System (PC 400) are the newly introduced platinum coils designed specifically to enhance filling efficiency by increasing coil diameter. Reported herein are the results of a comparison study to assess the PC 4009s filling advantage in the treatment of cerebral aneurysms as compared to conventional embolic coils (Controls). Particular focus was put on the extent to which the larger diameter affects acute packing density, embolization time and the aneurysm occlusion at 6 months post-treatment. Methods This was a single center, retrospective case-review of 111 aneurysm cases treated in 110 patients by the PC 400 (N=16) or Controls (N=95). The aneurysm and procedural characteristics listed below were evaluated. Aneurysm volume and packing density were calculated using AngioCalc (http://www.angiocalc.com), an open source aneurysm calculator endorsed by the manufacturers of the currently available coil systems. Aneurysm occlusion was graded using investigator reported Raymond Scale classification immediately post-procedure, and at 6 (±2) months when patient follow-up was available. The data was then evaluated for statistical significance. Results Conclusion Aneurysm embolization with PC 400 achieved statistically significant greater packing density compared with conventional coils. This was achieved with less procedure time and less total number of coils despite statistically significant greater aneurysm volume. For patient follow-up, the seven PC 400 cases had a greater percentage of Class I Raymond Scale occlusion compared to the controls with available data at 6 months. Our data confirms that when compared to conventional coils, the PC 400 is indeed more efficient in the embolization of cerebral aneurysm, without affecting accessibility or safety. Competing interests A Patel: Penumbra, Inc. A Kamath: None. M Polykarpou: None. J Mascitelli: None. A Patel: None. H Moyle: None.

https://jnis.bmj.com/content/neurintsurg/4/Suppl_1/A38.1.full.pdf

Maritsa F Polykarpou

Papers

An update to the Raymond–Roy Occlusion Classification of intracranial aneurysms treated with coil embolization

Initial experience with Penumbra Coil 400 versus standard coils in embolization of cerebral aneurysms: a retrospective review

Analysis of early angiographic outcome using unique large diameter coils in comparison with standard coils in the embolization of cerebral aneurysms: a retrospective review

P-033 Aneurysm embolization treatment efficiency: comparing the penumbra coil 400TM system to conventional coils