504 - Characterization of Glue Penetration with Balloon Occlusion Microcatheter Use During N-Butyl Cyanoacrylate Prostatic Artery Embolization

Purpose: To use the extended Glue Penetration Index Score (eGPIS){1} to characterize n-butyl cyanoacrylate glue penetration in prostatic artery embolization (PAE) when performed using a balloon occlusion microcatheter.

Materials and Methods: Twenty-five consecutive patients who underwent PAE using n-butyl cyanoacrylate glue from December 2023 through July 2025 by a single experienced operator (13 years’ experience) were retrospectively reviewed. Baseline patient age and prostate volume (PV) were recorded. Microcatheter choice, ratio of glue dilution with ethiodized oil, and total volume of glue injected were tabulated. Un-subtracted high-quality angiographic images were obtained in straight anterior-posterior views immediately after glue injection and microcatheter removal. Images were independently reviewed by two physicians (Observer A, 13 years’ experience; Observer B, 2 years’ experience) who each assigned a glue penetration score from 0 to 3.5 for each hemi-gland according to the eGPIS system proposed by von Stempel et al.{1} Values were reported as means with standard deviations. Comparisons used Student’s t-tests. Embolization-specific adverse events were tabulated using Clavien-Dindo classification.{2}

Results: Patients who underwent PAE with glue using a balloon occlusion microcatheter (n=21) had mean age of 70.9±6.5 years and PV of 126±73 mL. All cases were technically successful. The dilution of cyanoacrylate to ethiodized oil was 1:10 in 16 cases and 1:8 in 5 cases. Mean total gland glue volume injected was 1.6±0.6 mL. Observer A’s mean hemi-gland eGPIS was 3.0±0.7 and mean whole gland eGPIS was 6.0±1.1. Observer B’s mean hemi-gland eGPIS was 3.2±0.4 and mean whole gland eGPIS was 6.4±0.8. Interobserver differences in hemi- and whole gland eGPIS values were not significant (p=0.15 and 0.23, respectively). Nontarget embolization adverse events were not observed. One grade 3 adverse event occurred with gland tissue sloughing requiring intervention.

Conclusion: PAE performed using cyanoacrylate glue with a balloon occlusion microcatheter achieved high levels of glue penetration into prostate tissue, as quantified by the eGPIS system. No reflux or nontarget embolization events occurred. The eGPIS values observed in this study were substantially higher than those reported elsewhere in procedures performed without a balloon occlusion microcatheter.¹ However, validation of this observation with direct-comparison study is needed. Correlation of degree of glue penetration with clinical outcomes is likewise in need of further study.