Recanalization and particle exclusion after embolization of uterine arteries in sheep: a long-term study

Objective: To compare the Iona-term evolution of uterine arteries after embolization with the two most commonly used embolic agents for fibroid embolization: nonspherical polyvinyl alcohol (PVA) particles and trisacryl gelatin microspheres (TGMS). Design: Prospective study. Setting: University-based interventional radiology, pathology, and reproductive physiology units. Animal(s): Two groups of 10 sheep embolized in the uterine artery. Intervention(s): Embolization of the uterine artery with either 600-1000 mu m nonspherical polyvinyl alcohol (PVA) particles or with 700-900 mu m trisacryl gelatin microspheres (TGMS). Animals were synchronized and naturally inseminated. Animals were killed at 26 months. Main Outcome Measure(s): Uteri were examined pathologically for vessel size, site of occlusion, recanalization rate of vessels, and particle location within the vascular wall. Result(s): The PVA particles were more numerous in the vessels' lumen than the TGMS particles (13.3 +/- 20.8 vs. 2.5 +/- 2.7), were located more proximally than TGMS (97% vs. 68% in the trunk and first branches of the uterine artery), and were found almost exclusively in the intima (99.2%). In contrast, 54.4% of the TGMS particles were found in the intima. and 45.6% partially or totally excluded. The rate of recanalization was not statistically significantly different for PVA and TGMS (65.2% vs. 60.6%). Conclusion(s): The long-term evolution of uterine arteries was different after uterine artery embolization with PVA and TGMS because PVA particles formed large-sized aggregates that occluded proximal vessels and remained in the vessel intima. Microspheres occluded more distal vessels, and about 50% of them were partially or totally excluded from the vessel. (Fertil Steril (R) 2009;91:884-92. (c) 2009 by American Society for Reproductive Medicine.)