Table 4:

Primary histopathologic findings after coil embolization of experimental aneurysms

Species, Aneurysm	Neck	Dome	Reaction Around and Inside Coils	Inflammation Reaction
Canine, lateral wall7,41,52,57	Neointima in the obliterated and recanalized aneurysms (170.00 ± 42.43 μm)	Variably organized connective tissue	Neointima and connective tissue tightly adhering to the coils	Minimal inflammatory reaction
Canine, bifurcation28,29,43,52	Very thin neointima (29.80 ± 24.35 μm); frequent endothelialized clefts	Little-to-no residual thrombus; organized vascularized fibrocellular tissue	Coils apparently bare or covered by a neointimal membrane of variable thickness	Minimal degree of inflammation
Swine, lateral wall35,41,55,56	Thick fibrous neointimal membrane >1000 μm	Dense fibrotic tissue	Neointima and connective tissue tightly adhering to the coils	Attenuated inflammatory reaction
Rabbit, bifurcation8,15,18,30,31	No endothelialization	No evidence of organized thrombus	Uncovered coils in the lumen and no fibrosis between the loops of coils	Severe chronic or no major inflammatory reaction
Rabbit, elastase10,44–46,72	Partial or complete thin neointimal coverage	Loose hypocellular vascularized connective tissue; no contractile cells and no collagen deposition	No endothelial layer covering the coils close to the aneurysm neck	Marked-to-mild localized chronic inflammatory infiltration