Single-center retrospective comparative study of 40-120 μm versus 100-300 μm trisacryl gelatin microspheres as the main embolic agents for prostatic artery embolization.

PURPOSE To compare the safety and efficacy of trisacryl gelatin microspheres (TGM) with diameters of 40-120 μm (TGM 40-120) vs. 100-300 μm (TGM 100-300) as the primary embolic agents for prostatic artery (PA) embolization (PAE).

METHODS This single-center retrospective comparative study included patients with symptomatic benign prostatic hyperplasia treated with PAE using TGM 40-120 (group A) or TGM 100-300 (group B) over a two-year period. Evaluation included International Prostate Symptom Score (IPSS), quality of life score (QoL), prostatic volume (PV), post-void residual (PVR), and percentage of prostatic infarction (pPI) measured by contrast-enhanced ultrasound. Clinical success was defined as post-PAE reduction of IPSS ≤ 15 points with a decrease of at least 25% from the baseline, QoL score ≤ 3 points or a decrease of at least 1 point from baseline, and successful bladder catheter removal (for catheter-dependent patients). Adverse events were recorded and graded using the modified CIRSE classification system for complication reporting.

RESULTS Most baseline characteristics did not differ significantly between group A (n = 21) and group B (n = 31). At 3 months post-PAE, there were no statistically significant differences between groups in improvement of IPSS (group A: 49.5 ± 26.1%, group B: 51.8 ± 23.3%, P = 0.403) or QoL (group A: 54.7 ±3 1.6%, group B: 51.2 ± 14.1%, P = 0.589), nor in reduction of PV (group A: 35.5 ± 16.9%, group B: 28.4 ± 11.0%, P = 0.104) or PVR (group A: 59.8 ± 23.9%, group B: 60.4 ± 28.5%, P = 0.934). However, pPI (calculated 1-4 days post-PAE) was significantly higher in group A (48.3 ± 16.2% vs. 30.3 ± 11.9%, P = 0.007). Mid-term PV reduction was also significantly greater in group A (31.4 ± 21.4% vs. 12.2 ± 10.2%, P = 0.030). There were more complications in group A (7/21 vs. 4/31, P = 0.095). Three complications in group A were grade 3a events (bladder wall ischemia, n = 2; persistent severe anal and perineal pain requiring hospitalization and opioids, n = 1). No grade 3 events were observed in group B (P = 0.060). Clinical success rates at 6, 12, 24, and 36 months post-PAE were 76.2%, 76.2%, 71.1%, and 71.1%, respectively, for group A, and 87.1%, 83.9%, 79.9%, and 79.9%, respectively, for group B (P = 0.451).

CONCLUSION Compared with TGM 100-300, PAE with TGM 40-120 appears to provide similar clinical benefit but results in significantly higher pPI and greater mid-term prostate shrinkage. Ischemic complications may be more frequent and more severe with the smaller microspheres.

CLINICAL SIGNIFICANCE This is the first systematic comparison between the smallest and the second smallest commercially available TGM sizes in the clinical context of PAE. These findings may help guide ongoing research to identify the most appropriate embolic material for PAE.