Long-term results with Matrix coils vs. GDC: an angiographic and histopathological comparison

Neuroendovascular surgery

Neuroendovascular surgery and interventional neuroradiology both describe the catheter-based (most often) endovascular diagnosis and treatment of vascular lesions affecting the brain and spinal cord. This article traces the evolution of these techniques and their current role as the dominant and frequently standard approach for many of these conditions. The article also discusses the important changes that have been brought to bear on open cerebrovascular neurosurgery by neuroendovascular surgery and their effects on resident and fellow training and describes new concepts for clinical care.

Emergence of the white-collar sign after coil embolization of cerebral aneurysms

BACKGROUND

The white-collar sign (WCS) is represented by the formation of neointimal tissue at the level of the aneurysm neck as the successful outcome on follow-up angiography after coil embolization. WCS has been reported only in aneurysms treated with Matrix® coils. This is the first study to report WCS emergence in aneurysms treated with bare platinum coils, and potential factors associated with WCS emergence were evaluated.

METHOD

Total 130 unruptured (female: male ratio, 100: 30; mean age, 60 years) cerebral aneurysms were treated with coil embolization. Embolization status was assessed immediately and 1 year after treatment, and emergence of WCS in follow-up angiography was assessed. We evaluated the association between WCS emergence and aneurysm location, dome diameter, neck diameter, dome-neck ratio, and type of coil used (bare platinum or bioactive).

RESULTS

WCS appeared in nine aneurysms (6.9%), of which six were treated only with bare platinum coils. Neck diameter was significantly smaller in the WCS-positive group than in the WCS-negative group. The proportion of aneurysms treated with bioactive coils was not significantly different between the groups. Immediate embolization status in the WCS-positive group tended to be slightly better than that in the WCS-negative group. No aneurysmal morphological characteristics other than small neck diameter were associated with WCS emergence.

CONCLUSIONS

WCS is not specific to bioactive coil usage. Small neck diameter was significantly associated with WCS emergence in our series. Further investigations to clarify the predictors of WCS will contribute to progress of aneurysmal embolization.

Coil type does not affect angiographic follow-up outcomes of cerebral aneurysm coiling: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Previous studies varied in their conclusions about the superiority of second-generation coils compared with bare platinum. In this systematic review and meta-analysis, we assessed differences in reported unfavorable angiographic outcomes of cerebral aneurysms treated with coil embolization as a function of coil type.

MATERIALS AND METHODS

This systematic review covered 1999-2011 through the use of Ovid MEDLINE and EMBASE. Search terms were "subarachnoid hemorrhage," "intracranial aneurysms," "endovascular treatment," and "coiling." Inclusion criteria were studies reporting >50 aneurysms with imaging follow-up. We defined "unfavorable angiographic outcome" as either "recanalization," <90% occlusion, or "incomplete occlusion" at follow-up. Rates of unfavorable outcomes were pooled through the use of random effects models and compared across various coil types. Multivariate random effects meta-regression models were used to further explore the differences in outcomes related to coil type.

RESULTS

We included 82 studies, comprising 90 patient cohorts, among which, 65 (72%) used bare platinum coils, 8 (8.9%) used Matrix, 11 (12%) used HydroCoil, and 6 (6.7%) used Cerecyte. The overall unfavorable outcome rate was 19% (95% CI: 17%,21%). Unfavorable outcome rates were 20% (95% CI: 17%, 22%) for bare platinum coils, 23% (95% CI: 16%, 29%) for Matrix, 15% (95% CI: 9%, 21%) for HydroCoil, and 15% (95% CI: 7%, 23%) for Cerecyte, respectively. The difference in unfavorable outcome rates among the various coil types was not statistically significant after adjusting for baseline characteristics, including aneurysm size, rupture status, and follow-up duration.

CONCLUSIONS

The rate of unfavorable angiographic outcomes was not statistically different across the major approved coil types. The quality of the evidence, however, remains low because of high heterogeneity, small sample size, and potential publication bias.

Influence of Coil Geometry on Intra-Aneurysmal Packing Density: Evaluation of a New Primary Wind Technology

Introduction: This prospective randomized double-blinded in-vitro study was conducted to determine the relative Packing Density (PD) of the new Deltapaq coil (Micrus Endovascular) as compared to Micrus’s conventional filling CHE (Helipaq) and finishing CFS (Ultipaq) coils. Methods: Two physicians independently deployed the coils under fluoroscopy into a 4mm berry shaped glass aneurysm. Each coil tested was a 4mm × 35cm coil specially made for this study. Physicians and observer were blinded as to the type of coil. Five samples per group, per operator, were deployed. Results: mean PD were 36.6% (Helipaq), 37.9% (Ultipaq) and 40.4% (Deltapaq). Two-sample T-test showed a significantly higher PD of Deltapaq versus Helipaq (p < 0.022). Discussion: Higher coil PD and better neck coverage may provide an increased biomechanical stability and may potentially reduce the recanalization rate of aneurysms. Conclusion: The new Deltapaq coil may have the potential to achieve higher packing densities in the treatment of aneurysms.

In vivo experimental intracranial aneurysm models: a systematic review

Animal models are necessary to develop and test innovations in aneurysm therapy before clinical introduction. This review aims at identifying the most likely candidates for standardizing preclinical testing of aneurysm devices. We systematically searched electronic databases for publications on animal aneurysm models from 1961-2008 to assess the methodologic quality of the studies and collect data on the patency and angiographic and pathologic outcomes of treatments. There has been a steady increase in the annual number of publications with time. Species that were most frequently used were dogs, rabbits, and rodents, followed by swine. Most publications are single-laboratory studies with variables and poorly validated outcome measures, a small number of subjects, and limited standardization of techniques. The most appropriate models to test for recurrences after endovascular occlusion were the surgical bifurcation model in dogs, and the elastase-induced aneurysm model in rabbits. A standardized multicenter study is needed to improve the preclinical evaluation of endovascular devices in aneurysm therapy.

Clinical experience with Matrix2 360 degrees coils in the treatment of 100 intracranial aneurysms

BACKGROUND

The M2-360 degrees is a recent class of aneurysm coil. This device combines the second generation of bioactive copolymer coating, which is intended to promote aneurysm fibrosis, with the "360 degrees " design, which is meant to improve uniformity and density of packing. This study evaluates the safety and angiographic stability of these devices.

METHODS

This was a retrospective review of 86 consecutive patients with 100 intracranial aneurysms that were treated using M2-360 degrees s. Follow-up was done at 6 and 12 months.

RESULTS

Seventy-eight aneurysms were coiled solely with M2-360 degrees s, and 22 aneurysms were treated with a combination of coils. In mixed-coil cases, the average percentage of coil volume consisting of M2-360 degrees coils was 78%. Procedure-related neurologic complications occurred in 6 patients (7%). Initial complete occlusion was obtained in 80 aneurysms. Of 76 aneurysms with 6-month angiographic follow-up, 4 (5.3%) revealed further occlusion, 54 (71.1%) were unchanged, and 18 (23.7%) showed recanalization. Of 38 aneurysms with 12-month follow-up, 1 (2.6%) revealed further occlusion, 23 (60.5%) were unchanged, and 14 (36.8%) showed recanalization. Six- and 12-month angiograms showed major recanalization (requiring further coiling) in 3.9% and 15.8% of cases, respectively.

CONCLUSIONS

The risk of complications with M2-360 degrees -treated aneurysms is comparable with reports of other coils, indicating that M2-360 degrees s are relatively safe. Although the initial occlusion rate is higher than that in other coiling series, recanalization rates were similar to those obtained with other coil designs. This study does not demonstrate an advantage with M2-360 degrees s.