Normal Porcine Ureter Retains Lumen Wall Integrity but Not Patency Following Catheter-Directed Irreversible Electroporation: Imaging and Histologic Assessment over 28 Days.

ABSTRACT

PURPOSE: To evaluate the effect of catheter-directed irreversible electroporation (IRE) on the integrity, patency, and function of the normal porcine ureter. MATERIALS AND METHODS: A catheter-mounted electrode was used to perform fluoroscopy-guided IRE in 8 healthy pigs. Two unilateral ablations (90 pulses at 2,000 V, 100 µs) were performed in each animal in the proximal and distal ureter. Serum creatinine measurements and contrast-enhanced computed tomography imaging were performed at 1, 7, 14, 21, and 28 days after IRE, and findings were compared with baseline values by Student t test. Two animals each were euthanized at 1, 7, 14, and 28 days after IRE for histologic assessment of treatment effects. Quantitative histologic analysis of regeneration and healing of the ureteral wall was graded on a five-point scale. RESULTS: IRE was successfully performed in all animals. Preservation of ureteral wall integrity was confirmed by the leakage-free passage of contrast medium in the treated ureter of all animals through the observation period. Ureteral strictures and associated renal pelvicaliceal dilation were observed in all animals by study days 7 (P = .005) and 14 (P = .007) and did not resolve by day 28. Urothelial recovery was observed in tissue samples from day 7, with progressive replacement of the tunica muscularis with granulation tissue. Despite extensive scarring of the tunica muscularis, full recovery of the urothelium was observed by day 28. CONCLUSIONS: The normal porcine ureter retains lumen wall integrity and function following catheter-directed IRE. Scarring of the tunica muscularis in the treated ureter results in stricture formation and reduction of lumen patency.