Histopathological differences of experimental aneurysms treated with bare platinum, fibered, and bioactive coils.

To evaluate the histopathological features of experimental aneurysms embolized with bare platinum, fibered, and bioactive coils. Twelve experimental aneurysms were constructed in three swine. The aneurysms were divided into four groups and were embolized using a bare platinum coil alone (P group, n = 2), a bioactive coil alone (B group, n = 2), a combination of fibered and bare platinum coils (F/P group, n = 4) and a combination of fibered and bioactive coils (F/B group, n = 4). Histopathological data for all aneurysms recorded at 63 days were analyzed in terms of neointima formation, fibrosis, foreign-body giant-cell infiltration, and organization. Fibrosis was significantly greater in group B compared with that in group F/P (p = .02).　 Inflammation with foreign-body giant-cell infiltration was significantly greater in groups F/P and F/B compared with that in groups P and B (p = .007). The present study revealed that the embolic effect of fibered coils was not a thrombus but instead was a foreign-body response in the chronic phase.