Comparative assessment of biodegradable-antireflux heparine coated ureteral stent: animal model study

Abstract

Background Double J ureteral stents are widely used on urological patients to provide drainage of the upper urinary tract. Unfourtunately, ureteral stents are not free from complications, as bacterial colonization and require a second procedure for removal. The purpose of the current comparative experimental study is to evaluate a new heparin-coated biodegradable antireflux ureteral stent (BraidStent®-H) to prevent urinary bacterial colonization. Methods A total of 24 female pigs were underwent determination of bacteriuria and nephrosonographic, endoscopic and contrast fluoroscopy assessment of the urinary tract. Afterward, were randomly assigned animals to Group-I, in which a 5Fr double-pigtail ureteral stent was placed for 6 weeks, or Group-II, in which a BraidStent®-H was placed. Follow-up assessments were performed at 1, 3, 6, 8, 12 weeks. The final follow-up includes the above methods and an exhaustive pathological study of the urinary tract was accomplished after 20 weeks. Results Bacteriuria findings in the first 48 h were significant between groups at 6 h and 12 h. Asymptomatic bacteriuria does not reach 100% of the animals in Group-II until 48 h versus Group-I where it appears at 6 h. The weekly bacteriuria mean rate was 27.7% and 44.4% in Group I and II respectively, without statistical significance. In Group II there were no animals with vesicoureteral reflux, with statistical significance at 3 and 6 weeks with Group-I. The 91.2% of stents in Group-II were degraded between 3 and 6 weeks, without obstructive fragments. Distal ureteral peristalsis was maintained in 66.6–75% in Group-II at 1–6 weeks. Conclusions The heparin coating of BraidStent® allows an early decrease of bacterial colonization, but its effectiveness is low at the long term. Heparin coating did not affect scheduled degradation rate or size of stents fragments. BraidStent®-H avoids the side effects associated with current ureteral stents, thus should cause less discomfort to patients.

Assessment of a Coated Mitomycin-Releasing Biodegradable Ureteral Stent as an Adjuvant Therapy in Upper Urothelial Carcinoma: A Comparative In Vitro Study

“…The optimal combination of polymers and copolymers in the stent is determined by the requirements of their placement in the upper urinary tract [ 10 , 20 ]. The main current limitations to the development of biodegradable ureteral stents (BUS) are related to the control of the degradation rate and the size of the degradation fragments [ 10 , 20 , 21 , 22 , 23 ]. For this reason, a combination of polymers and copolymers with different degradation rates (always with degradation mainly by hydrolysis when placed in urine) are chosen to produce BUS.…”

“…Comparisons of this new design (BraidStent-SF-MMC1 or -2) with other biodegradable ureteral stents made of PGA and Glycomer TM 631 have been experimentally evaluated in the literature [ 21 , 22 , 23 ]. We found that, as with Braidstent groups 1 and 2 in the current study, coating with SF and MMC caused a significant reduction in the rate of ureteral stent degradation, from 6–7 weeks to 13–14 weeks ( Figure 5 ) [ 21 , 22 , 23 ].…”

“…Comparisons of this new design (BraidStent-SF-MMC1 or -2) with other biodegradable ureteral stents made of PGA and Glycomer TM 631 have been experimentally evaluated in the literature [ 21 , 22 , 23 ]. We found that, as with Braidstent groups 1 and 2 in the current study, coating with SF and MMC caused a significant reduction in the rate of ureteral stent degradation, from 6–7 weeks to 13–14 weeks ( Figure 5 ) [ 21 , 22 , 23 ]. Despite significant differences in baseline thickness and weight between the BraidStent-SF, and the BraidStent-SF-MMC1- and -2 groups, no differences in overall degradation time were seen ( Figure 4 , Figure 5 , and Figure 9 ).…”

Encrustation in Urinary Stents

“…The heparin coating allows for an early reduction in bacterial colonization. However, this effect is limited in the long term [55]. Champagne et al examined the degradation of zinc compounds in artificial urine to try to circumvent the limitations of alloys based on iron and magnesium regarding biocompatibility and controlled degradation under physiological conditions.…”

Cytotoxicity Assessment of a New Design for a Biodegradable Ureteral Mitomycin Drug-Eluting Stent in Urothelial Carcinoma Cell Culture

“…To perform the in vitro study, 24 fragments of a 10 mm long BraidStent ® (JUMISC, Cáceres, Spain) biodegradable ureteral stent were made by combining biodegradable polymers and copolymers—Glycomer™ 631 and polyglycolic acid (PGA), at a ratio of 54% and 46%, respectively [ 12 , 13 , 14 ]. Two 0.17 mm thick threads of Glycomer™ 631 and two 0.14 mm thick threads of PGA, all 10 mm long, were used to manufacture the stent.…”