Comparison of platinum and first-generation Matrix coils in under-packed canine side-wall aneurysms: evaluation of progressive thrombosis.
ABSTRACT There is much speculation in reference to the occurrence and mechanisms of progressive aneurysm occlusion after treatment with bioactive coils. However, to our knowledge, there are no studies documenting the impact on progressive occlusion in aneurysms that are intentionally under-packed.
A total of 24 experimental side-wall aneurysms were created in canine common carotid arteries. Of these 24, 9 were treated with Guglielmi detachable coils (GDC) and 15 with first-generation Matrix (Matrix1) coils to packing densities of 22% or less. Angiograms were obtained immediately after treatment and again at the time of explant at 2 weeks, 8 weeks, or 12 weeks, and were graded utilizing the Raymond scale. At the time of the final angiography and explant all aneurysms were histologically processed and evaluated.
At the conclusion of initial coiling, near or complete occlusion was achieved in 7 of the 15 aneurysms (47%) treated with Matrix1 coils and in 2 of the 9 (22%) treated with GDC. Of the aneurysms that were incompletely occluded, six of eight (75%) treated with Matrix1 coils and two of seven (29%) treated with GDC showed progressive thrombosis at explant. Histopathological analysis demonstrated that the aneurysms treated with Matrix1 coils had increased fibrocellular tissue and inflammation, with less histological recanalization or vascular spaces, relative to those treated with GDC.
Experimental wide-necked side-wall canine aneurysms suboptimally treated with first-generation Matrix1 coils had a higher incidence of progressive occlusion and on histological analysis showed evidence of more advanced thrombus organization than did those treated with GDC.
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ABSTRACT: Endovascular coil embolization has become an accepted alternative for the treatment of intracranial aneurysms. The purpose of this study was to evaluate the clinical safety and the angiographic stability of aneurysm occlusion with a new class of biologically active platinum coils after a 6-month period. Twenty-five patients with 25 intracranial aneurysms were treated by selective embolization with a new coated bioactive coil (Matrix; Boston Scientific Neurovascular). Matrix coils were used alone in 6 patients and in combination with Guglielmi detachable coils (GDCs; Boston Scientific Neurovascular) in 19. Angiographic results, procedure-related complications, and adverse neurological events during the follow-up period were recorded. Magnetic resonance angiography was performed at 6 months in all patients. Initial angiographies demonstrated complete occlusion in 17 patients, residual neck in 7, and a persisting aneurysm in 1. The clinical follow-up showed stable results in all patients. The grade of aneurysm occlusion at 6 months improved in 4 patients, remained stable in 15, and deteriorated in 6. Three patients needed retreatment because of a major aneurysm recanalization. Angiographic recurrences in cases of aneurysms treated with a combination of Matrix coils and GDCs occurred within the expected range for bare platinum coils. Two of 3 patients needing retreatment had been treated with Matrix coils alone. Stable results were obtained predominantly when Matrix coils were combined with bare platinum coils. A prospective, randomized study is necessary to assess the potential benefit of Matrix coils for patients treated by endovascular techniques.Stroke 11/2005; 36(10):2176-80. · 6.02 Impact Factor
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ABSTRACT: To evaluate the effectiveness of Guglielmi detachable coils (GDCs) filled with collagen threads in the permanent treatment of experimental aneurysms. Seventeen side-wall aneurysms were surgically constructed in the canine common carotid artery; six were treated with conventional GDCs and 11 with collagen-filled GDCs. One aneurysms was removed at 1 week, the others were studied by digital subtraction angiography for a period of 8 to 12 weeks. Longitudinal sections of all aneurysms were examined by light microscopy. Angiograms obtained throughout the follow-up period showed no significant difference between aneurysms treated with conventional GDCs and those treated with collagen-filled GDCs. Light microscopy revealed a dense meshwork of newly formed collagen and fibroblasts near the collagen-filled GDCs, whereas a loose cellular meshwork surrounded the conventional GDCs at 8 and 12 weeks after treatment. Collagen threads within GDCs do not noticeably improve angiographic treatment of experimental aneurysms; however, these threads did induce local proliferation of fibroblasts and production of collagen within the aneurysmal cavities.American Journal of Neuroradiology 05/1997; 18(4):667-72. · 3.68 Impact Factor
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ABSTRACT: Ion implantation is a surface-modification technology that creates a borderless surface on protein-coated platinum; this change in physical and chemical properties on the surface of Guglielmi detachable coils (GDCs) appears to enhance cell proliferation and adhesion. Our purpose was to evaluate the effect of ion implantation on GDCs in an experimental aneurysm model. GDCs were coated with either type I collagen, fibronectin, vitronectin, laminin, or fibrinogen. Using He+ or Ne+ 1 x 10(14-15) ions/cm2, ion implantation was performed on these protein-coated GDCs (GDC-Is). A total of 56 experimental aneurysms were constructed microsurgically in the common carotid arteries of 28 swine. These experimental aneurysms were embolized with standard GDCs (n = 23), collagen GDC-Is (n = 11), vitronectin GDC-Is (n = 6), laminin GDC-Is (n = 4), fibrinogen GDC-Is (n = 6), and fibronectin GDC-Is (n = 6). The animals were sacrificed at day 14 after coil embolization. The physical properties of the new coils (friction on delivery, deployment into aneurysms, trackability, etc) and the development of tissue scarring and neoendothelium across the aneurysm's orifice were evaluated macroscopically and microscopically. No evidence of increased coil friction/stiffness was observed during delivery of GDC-Is through microcatheters in this aneurysm model. A more intense scar formation and neoendothelium at the neck of aneurysms were observed macroscopically when treated with GDC-Is. Significant differences in the proportion of neck coverage between standard GDCs (48.3% +/- 20.5%) and all GDC-I groups were observed (collagen GDC-I-89.4% +/- 14.9%, P < .01; vitronectin GDC-I-71.5% +/- 7.0%, P < .05; laminin GDC-I-76.5% +/- 11.0%, P < .05; fibrinogen GDC-I-74.8% +/- 13.9%, P < .05; fibronectin GDC-I-87.5% +/- 15.0%, P < .01). Light microscopy showed a well-organized fibrous tissue bridging the aneurysm's neck when using GDC-Is, whereas only a fibrin-like thin layer covered the standard GDC surfaces. GDC-Is indicated a more intense inflammatory response in the aneurysm body and dome and faster re-endothelial coverage of the neck of the aneurysm. This accelerated histologic response may decrease the chances of coil compaction and aneurysm recanalization. This technology may improve anatomic and clinical outcomes in patients harboring intracranial aneurysms.American Journal of Neuroradiology 20(10):1992-9. · 3.68 Impact Factor