Abstract
We evaluated the long-term follow-up angiographical status of aneurysms treated with Guglielmi detachable coils (GDCs). Between December 1997 and December 2001, 42 aneurysms were embolized using GDCs and followed up for long-term periods. The initial rates of occlusion were 100% (total occlusion: TO) for 17 aneurysms (40.5%), ≥90% (subtotal occlusion: STO) for 15 aneurysms (35.7%) and less than 90% (partial occlusion: PO) for 10 aneurysms (23.8%). No recurrence was observed in completely occluded aneurysms. Of the 25 aneurysms that were incompletely occluded initially, progressive thrombosis occurred in 18, 5 were stable, and remnant regrowth occurred in 2. There was a small but insignificant difference on mean volume embolization rate (VER) between the group of progressive thrombosis in PO (25.22±7.10%) and stable and remnant regrowth in PO (17.35±3.09%).
Because of the potential difficulty in predicting the angiographical outcome based only on VER, we introduced an Embolization Score (ES) to estimate the angiographical status in follow-up periods. This score is multifactorial, comprising the aneurysmal size (≥10 mm), neck shape (wide neck), direction of aneurysm (terminal type) and volume embolization rate (≤20%). ES is derived by adding 1 point assigned for each feature indicated in the parentheses. Less than 2 points on this score strongly suggests long-term stability after embolization. This score may be useful for predicting the outcome of aneurysms incompletely treated with GDCs.
