Matrix and Bioabsorbable Polymeric Coils Accelerate Healing of Intracranial Aneurysms

Abstract

Background and Purpose— Acceleration of intra-aneurysmal clot organization and fibrosis may be a solution to preventing aneurysm recanalization after endovascular treatment. The purpose of this study was to evaluate the short-term efficacy and long-term safety of the new Matrix coil system. Methods— Matrix coils consist of thin platinum coils covered with a bioabsorbable, polymeric material (polyglycolic acid/lactide). Fifty-two experimental aneurysms were created in 26 swine. All of the aneurysms were tightly packed with Matrix or Guglielmi detachable coils (GDC). Comparative angiographic and histopathologic data were analyzed at 2 weeks (n=14), 3 months (n=6), and 6 months (n=6) after embolization. Results— Three aneurysms treated with GDC ruptured despite tight packing. No recanalization or rupturing was observed in the aneurysms embolized with Matrix coils. At 14 days after embolization, the aneurysms treated with Matrix coils exhibited a more extensive area of organized thrombus when compared with the aneurysms treated with GDC (87% versus 75%, P =0.008, n=11). At 3 months, both Matrix and GDC-treated aneurysms demonstrated complete clot organization. Neck tissue thickness was higher in Matrix-treated aneurysms at 14 days and 3 months, but not at 6 months. No untoward parent artery stenosis was observed in aneurysms treated with Matrix during follow-up. The angiographic cross-sectional area of the Matrix-treated aneurysms was smaller than those treated with GDC at the 3 months. Conclusion— Matrix accelerated aneurysm fibrosis and neointima formation without parent artery stenosis. The Matrix system might prevent aneurysmal recanalization after endovascular treatment of cerebral aneurysms.

In Vivo Experimental Intracranial Aneurysm Models: A Systematic Review

“…68 Many investigators have published scales that offer a rational, if not a validated basis, for assessing the performance of an implant, by giving points for features considered favorable for healing, including neck coverage with neointima, thickness of neointimal layer, or clot organization at the dome. 11,19,[43][44][45][46][47]56,69 These semiquantitative scales have largely been confined to single-center experiences; they have not been reproduced or validated. No one, to our knowledge, has been able to show that these criteria predict better in vivo clinical performances, however.…”

“…48 When all specimens showed permanent occlusions and favorable healing characteristics at some delayed time points, as seen in swine aneurysms, then some earlier timeframe was chosen, in hopes of detecting accelerated healing with some new material. 56 In the long term, treated canine lateral wall aneurysms are completely occluded in most cases. 7,41,[51][52][53]57 Canine bifurcation aneurysms have a propensity for recurrences, however; therefore, they can reproduce the problem found in human aneurysms.…”

Validation and Initial Application of a Semiautomatic Aneurysm Measurement Software: A Tool for Assessing Volumetric Packing Attenuation

“…25 With these coils, aneurysm occlusion stability may be achievable even at VER of Ͻ 25%, and even large aneurysms may become candidates for successful embolization. Watanabe et al 26 have reported the hydrogel-coated coil as being a safe and feasible device for improving the packing efficacy in endovascular coil embolization.…”

Interventional Neuroradiology

“…Technological innovation continues with new coil designs incorporating bioactive materials such as fibroblast growth factor, 3,4 collagen, 5 and polyglycolic acid/lactide. 6 All of these materials have been shown to increase cellular response and healing potential in experimental aneurysms, and the widespread clinical use of Matrix coils 6 (Boston Scientific) has shown promising results in humans, although there have been anecdotal reports of an increase in embolic complications. The challenge of treating wide-necked and complex aneurysms has been the focus of balloon remodeling 7 and stent-assisted 8,9 techniques.…”