PARTIAL THROMBOSIS OF CANINE CAROTID BIFURCATION ANEURYSMS WITH CELLULOSE-ACETATE POLYMER

OBJECTIVE: To investigate the usefulness of a cellulose acetate polyme r (CAP) solution for partial thrombosis of aneurysms. METHODS: We crea ted 14 canine cervical carotid bifurcation aneurysms, 11 of which were subsequently thrombosed partially with CAP solution. We then conducte d angiographic and histological investigations. RESULTS: Nine aneurysm s were thrombosed 50 to 70% by volume, although a significant crescent crevice between the aneurysmal sac and the CAP mass was left in four of the aneurysms. In the remaining two aneurysms in which a crescent c revice had been seen in the initial stage of CAP injection, 80% and mo re than 95% thrombosis were needed to occlude the crevice, respectivel y. Follow-up angiograms of the seven aneurysms with no crescent crevic e revealed no shifts of position of the CAP mass toward the bottom of the aneurysm sac, but slight ballooning of the remnants was observed i n two of them. The angiograms of the other four aneurysms with signifi cant crescent crevices demonstrated rupture with a massive hematoma in one and shifts of the CAP mass with marked enlargement of remnants in three. Histologically, the seven aneurysms with no enlarged remnants had newly developed membranes consisting of endothelium, infiltrated s pindle-shaped cells, collagen, and elastic fibers. In contrast, in the three markedly enlarged aneurysms, there were only recent clots betwe en the CAP mass and the aneurysm lumen and no development of endotheli um. CONCLUSION: Partial thrombosis with CAP solution is useful to keep aneurysms in a stable configuration, unless a crescent crevice has be en left.