A New Liquid Embolic Agent(Embol) for Transcatheter Renal Artery Embolization: An Experimental Study in Rabbit

ABSTRACT

PURPOSE: To evaluate the effectiveness and safety of a new liquid embolic agent in renal arterial embolization in the rabbit, and its clinical applicability. MATERIALS AND METHODS: A new embolic agent, Embol, was obtained by partial hydrolysis of polyvinyl acetate and dissolved in a mixture of 45% ethanol and 55% non-ionic contrast medium. Its radioopacity was therefore good. An average of 0.8 cc(0.5-0.9 cc) of Embol was used to embolize the renal artery of one kidney in 15 rabbits. The immediate effect of this was examined angiographically 5 minutes after the procedure. To permit histologic examination, five rabbits in each group were sacrificed 3 days (I), 2 weeks (II), and 4 weeks (III) after embolization prior to embolization and prior to sacrifice, one rabbit in each group underwent renal scanning, and prior to sacrifice all underwent follow-up angiography. In three rabbits, blood urea nitrogen (BUN), creatinine, sodium(Na), and potassium(K) levels were measured before and 1, 3, 5, 7 and 14 days after embolization. RESULTS: Embol was easy to use and its radiopacity was good. Five minutes after embolization, angiography showed that total occlusion of the main renal or interlobar artery had been achieved in all rabbits. Serum BUN, creatinine, Na and K levels were within normal limits. Follow-up angiogram obtained in each group showed persistent occlusion of the renal artery in all but one rabbit in group I and one in group III. Renal scans revealed no evidence of radionuclide uptake in embolized kidneys, which were slightly enlarged in group I but became gradually smaller in groups II and III. In all animals, histologic examination showed diffuse coagulation necrosis of the embolized kidneys and in group III the cortex of these was extensively calcified. In group I the renal artery showed an apparently fresh occluding thrombosis, and in groups II and III a completely organized thrombosis was present. In group III this was calcified. CONCLUSION: Because of its good radioopacity, Embol is easy to controa, and is effective for renal artery embolization. As a permanent embolic agent, it appears suitable for clinical applications.