Feasibility of bioresorbable gelatin microspheres for organ-preserving transarterial embolization in arterial bleeding

Purpose: Bioresorbable gelatin microspheres (R-GMs) allow controlled and temporary embolic effects with adjustable degradation times. This study aimed to assess the feasibility and safety of R-GMs for temporary embolization in a porcine kidney model of arterial bleeding. Methods: The pigs were randomly assigned to the R-GM group or conventional gelatin microsphere (C-GM) group. Active bleeding was induced in ten male pigs by perpendicular puncturing the lower polar artery of the right kidney under ultrasound guidance. Immediate angiography confirmed arterial bleeding. Proximal embolization of the lower polar artery was performed in each group. Follow-up angiography to monitor embolization status, re-bleeding, and recanalization, with the follow-up time points assessing both the short- and long-term re-bleeding risk. On day 7, the pigs were sacrificed, and a histopathologic examination was performed to evaluate residual embolic material, inflammatory response, and tissue damage within the embolized lower polar area. Results: None of the animals showed re-bleeding. In the R-GM group, perfusion surrounding the injured vessel was restored as early as at 2 post-intervention hours, while the lower polar artery remained occluded in the C-GM group until day 7. Further, the R-GM group had a smaller infarct area in the lower pole of the right kidney than the C-GM group (5.80 ± 9.46 % vs. 93.32 ± 13.21 %, p < 0.001), with markedly lower levels of inflammatory cell infiltration and fibrosis. Conclusion: Temporary embolization with R-GMs effectively achieved hemostasis and allowed controlled recanalization, which minimized collateral tissue damage. These findings support the feasibility of R-GMs for organ-preserving embolization in acute arterial bleeding.