Development of the biologically active Guglielmi detachable coil for the treatment of cerebral aneurysms. Part II: An experimental study in a swine aneurysm model

BACKGROUND AND PURPOSE: Ion implantation is a surface-modification technolo gy that creates a borderless surface on protein-coated platinum; this chang e in physical and chemical properties on the surface of Guglielmi detachabl e coils (GDCs) appears to enhance cell proliferation and adhesion. Our purp ose was to evaluate the effect of ion implantation on GDCs in an experiment al aneurysm model. METHODS: GDCs were coated with either type I collagen, fibronectin, vitrone ctin, laminin, or fibrinogen, Using He+ or Nei 1 x 10(14-15) ions/cm(2), io n implantation was performed on these protein-coated GI)Cs (GDC-Is), A tota l of 56 experimental aneurysms were constructed microsurgically in the comm on carotid arteries of 28 swine. These experimental aneurysms were embolize d 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 fibronecti n GDC-Is (n = 6), The animals were sacrificed at day 14 after coil emboliza tion, The physical properties of the new coils (friction on delivery, deplo yment into aneurysms, trackability, etc) and the development of tissue scar ring and neoendothelium across the aneurysm's orifice were evaluated macros copically and microscopically, RESULTS: No evidence of increased coil friction/stiffness was observed duri ng delivery of GDC-Is through microcatheters in this aneurysm model. A more intense scar formation and neoendothelium at the neck of aneurysms were ob served macroscopically when treated with GDC-Is, Significant differences in the proportion of neck coverage between standard GDCs (48.3% +/- 20.5%) an d 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 cell-organized fibrous tissu e bridging the aneurysm's neck when using GDC-Is, whereas only a fibrin-lik e thin layer covered the standard GDC surfaces. CONCLUSION: GDC-Is indicated a more intense inflammatory response in the an eurysm 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 an atomic and clinical outcomes in patients harboring intracranial aneurysms.