The effects of uterine artery embolization with a new degradable microsphere in an experimental study

Background Transarterial particle embolization is a common treatment of uterine fibroids, aiming to obtain ischemia resulting in shrinking of the fibroid with preservation of normal uterine tissue. Embolization with non-degradable microspheres is established, but causes permanent occlusion of the arteries, affecting both the uterus as well as the fibroids. Purpose To evaluate in vivo degradation, local tissue effects, and possible recanalization following intra-arterial deposition of the new, degradable starch microspheres (DSM), in a short-term experimental pilot study. Material and Methods Under general anesthesia, unilateral transarterial embolization of the uterine artery (UA) with DSM 500-700 µm was performed in five female sheep. The animals underwent renewed angiography at different intervals after embolization (19-65 h) and were subsequently sacrificed. Histological examination was performed. Results Embolization with absent flow in the UA could be completed in five of six animals. At final angiographic evaluation, recanalization of the embolized arteries was evident in three sheep. At the gross postmortem examination, edema and discoloration indicating ischemia of the uterus at the embolized side, was observed in all the sheep. At histopathological examination, different stages of DSM degradation in the arterial branches were observed in both endometrium and myometrium. Mild-to-moderate vasculitis and mild-to-extensive ischemic changes were present along with degeneration of the uterine glands. Conclusion This short-term pilot study proved efficacy of embolization with DSM causing ischemic changes in the embolized organ, but also degradation of the DSM with subsequent recanalization of the embolized arteries.