Hepatic artery embolization using thermosensitive and slow-release drug as embolic agents: an experimental study in rabbits

Objective: To explore the feasibility and effect of hepatic artery embolization by using thermosensitive and slow-release drug as embolic agents in experimental rabbits. Methods: Hepatic artery embolization was carried out in fifteen New Zealand rabbits by using Lutrol® F 127 as embolic material. The rabbits were followed up for 4 weeks. Examinations, including liver function, CT scanning and angiography were regularly conducted. Every three rabbits were sacrificed immediately after the procedure and each time at 3 days, 1, 2 and 4 weeks after the procedure. The specimens were collected and sent for histopathologic examination. Results: After the operation, a transient elevation of ALT and AST level was observed in all rabbits, which reached its peak at the fifth day and turned to its initial level in two weeks. The complete occlusion of segmental artery branches and distal branches was achieved immediately after the embolization and no recanalization was detected on DSA performed 4 weeks after the operation. The liquefaction necrosis of liver parenchyma was demonstrated on CT scanning performed 1 to 2 weeks after the treatment, and punctate necrosis foci were still seen in 4 weeks. The CT value of the high-density lesions located within the embolized region gradually decreased with the time. This changing process of CT value spread from lesion's center to lesion's margin and lasted for 4 weeks. Pathological examination conducted immediately after the embolization showed that the tiny hepatic arteries were completely filled with Lutrol® F 127, and no embolic material could be found in hepatic sinusoids, portal veins or pulmonary arteries. At the 3th day and 1st, 2nd, 4th week, Lutrol® F 127 together with thrombosis was found in pre-sinusoidal arterioles and meanwhile complete disappearance of hepatic lobules with hyperplasia of interlobular connective tissue could also be seen. Conclusion: In the environment of body temperature, the thermosensitive and slow-release drug used as an embolic agent will quickly transform into solid state. Thus, the peripheral arterioles can be effectively occluded. Meanwhile, the drug release time is very long, lasting for four weeks. Therefore, Lutrol® F 127 is a safe and ideal embolic agent. (authors)