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 2000 V, 100 μs) were performed in each animal in the proximal and distal ureter. Serum creatinine measurements and contrast-enhanced CT imaging was performed at 1, 7, 14, 21 and 28 days post-IRE, and findings were compared to baseline values with the Student’s t-test. Two animals were sacrificed at 1, 7, 14 and 28 days post-IRE for histological assessment of treatment effects. Quantitative histology of regeneration and healing of the ureteral wall was graded using 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 in the treated ureter of all animals through the observation period. Ureteral strictures and associated renal pelvicalyceal dilation were observed in all animals by study day 7 (p=0.005) and 14 (p=0.007), which 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.

Acute and subacute effects of irreversible electroporation on normal common bile ducts in a rabbit model

“…However, the ureteral strictures were observed on day 7 post-IRE and did not resolve by day 28. 22,23 In the current study, four animals experienced biliary stricture and four experienced biliary dilatation from 7 to 28 days post-IRE. An alternative explanation for the different manifestation of biliary complication may be that the biliary dilatation may be secondary to a prior biliary structure or stenosis.…”

“…Thermal injury may also exist because of the complex environment of the in vivo study as reported in previous studies. 23 Furthermore, we performed our study on normal rabbit common bile duct rather than a tumor model, electrical properties and microenvironments are different between the tumor and normal tissue; tumor ablation with IRE may require different parameters and have different effects. Therefore, further studies are needed to optimize the treatment parameters of tumor ablation.…”

Physiological and Histopathological Effects of Electroporation Pulse on Stomach of Rats

“…Based on the non-thermal features of EP, several studies have found that EP is a potential ablation method for cavity organs such as the digestive tract. The safety and e cacy of IRE for the bile duct [9,10], heart [11], and urinary tract [12] have been demonstrated in animal studies. In our previous study, the safety and e cacy of EP for gastric tissue ablation was investigated in an animal model [8].…”

Electrical and thermal analyses of catheter-based irreversible electroporation of digestive tract

“…Moreover, the efficacy of thermalbased ablation will be affected by the heat-sink effect of blood flow from the adjacent large vessels. Therefore, IRE is suitable for sites that have contraindications for thermalbased treatment techniques [13].…”

“…Instead, a catheter-based electrode is suitable for preventing perforation or injury. Srimathveeravalli et al reported the safety and efficacy of full-thickness ablation in the porcine rectum and urinary tract by intraluminal catheter-based IRE [13,15]. Ueshima et al [16] showed that transmural ablation of the normal porcine common bile duct was feasible without affecting the duct patency via catheter-based IRE under endoscopy.…”