Angiographic and histological comparison of canine bifurcation aneurysms treated with first generation matrix and standard GDC coils.

INTRODUCTION: It is claimed that bioactive coils induce accelerated and more durable aneurysm healing. Data supporting this claim are quite limited. Our purpose was to compare the angiographic and histological results obtained following treatment with different coil types.
METHODS: Bifurcation type aneurysms were surgically created in 24 dogs and treated using standard clinical techniques. Eight were treated with Guglielmi detachable coils (GDC), eight with first-generation Matrix coils, and eight with a combination of GDC and Matrix coils. The aneurysms were explanted and final angiographic evaluations performed 12 weeks after treatment. Angiographic and histological outcomes were documented.
RESULTS: Increased coil compaction with aneurysm recurrence was found in aneurysms treated with first-generation Matrix coils as compared to standard GDC (P = 0.0001). In aneurysms treated with first-generation Matrix coils thrombus organization was better than in those treated with either standard GDC coils (P = 0.008) or with a combination of GDC and Matrix coils (P = 0.04). In aneurysms treated with first-generation Matrix coils there were no endothelialized vascular clefts within the coil mass, but they were seen in the majority of aneurysms treated with GDC or a combination of GDC and Matrix coils (P = 0.003).
CONCLUSION: Aneurysms treated with first-generation Matrix coils showed the greatest degree of coil compaction and aneurysm recurrence on the final angiographic evaluation. Aneurysms treated with first-generation Matrix coils showed enhanced thrombus organization and absence of vascular clefts at the aneurysm neck that were markedly different from those treated with bare platinum coils or a combination of GDC and Matrix coils.