Table 4:

Primary histopathologic findings after coil embolization of experimental aneurysms

Species, AneurysmNeckDomeReaction Around and Inside CoilsInflammation Reaction
Canine, lateral wall7,41,52,57Neointima in the obliterated and recanalized aneurysms (170.00 ± 42.43 μm)Variably organized connective tissueNeointima and connective tissue tightly adhering to the coilsMinimal inflammatory reaction
Canine, bifurcation28,29,43,52Very thin neointima (29.80 ± 24.35 μm); frequent endothelialized cleftsLittle-to-no residual thrombus; organized vascularized fibrocellular tissueCoils apparently bare or covered by a neointimal membrane of variable thicknessMinimal degree of inflammation
Swine, lateral wall35,41,55,56Thick fibrous neointimal membrane >1000 μmDense fibrotic tissueNeointima and connective tissue tightly adhering to the coilsAttenuated inflammatory reaction
Rabbit, bifurcation8,15,18,30,31No endothelializationNo evidence of organized thrombusUncovered coils in the lumen and no fibrosis between the loops of coilsSevere chronic or no major inflammatory reaction
Rabbit, elastase10,4446,72Partial or complete thin neointimal coverageLoose hypocellular vascularized connective tissue; no contractile cells and no collagen depositionNo endothelial layer covering the coils close to the aneurysm neckMarked-to-mild localized chronic inflammatory infiltration