Application of paclitaxel-eluting metal mesh stents within the pig ureter: an experimental study.
OBJECTIVE
The purpose of the present study is to compare the standard bare metal stents (BMS) with the Paclitaxel-Drug Eluting Stent (DES) in the ureter of a pig model.


METHODS
We report on an experimental study with ten female pigs weighing between 25 and 30 kg. The stents were randomly placed in either the right or left ureter in each of 10 study animals, for a total of 20 stented ureters. Ten ureters were stented with an R-Stent (Orbus Medical Technologies, Hoevelaken Netherlands), and ten with a Paclitaxel-Eluting Coronary Stent (Boston Scientific, Natick, MA, USA). Patency was measured by radiograph of the nephrostomy tract, intravenous urography and virtual endoscopy at 24 hours and 21 days after the initial procedure, respectively.


RESULTS
Free flow of urine through the stents into the bladder was documented in all stented ureters 24 hours after stent insertion by radiograph of the nephrostomy tract. At the 21 day follow-up examination, 5 R-Stents were found to be completely occluded and two partially stenosed, whereas no occluded stent was detected in the Paclitaxel-DES group. Pathology examination of the stents at 21 days follow-up showed that the obstructed R-Stents generated severe inflammation with metaplasia of the urothelium. The Paclitaxel-Eluting MS generated a mild inflammatory response within the ureteral lumen at the site of the stent, without hindering ureteral patency. R-stents proved to develop more hyperplasia compared to the Paclitaxel-Eluting MS.


CONCLUSIONS
Paclitaxel-DES, when compared with the standard R- Stent BMS, generated less inflammation and/or hyperplasia of the surrounding tissues, thus maintaining ureteral patency. Long-term animal trials are required to further validate our results.
Liatsikos
Evangelos N
EN
Department of Urology, University of Patras, School of Medicine, Patras, Greece. Liatsikos@yahoo.com
Karnabatidis
Dimitrios
D
Kagadis
George C
GC
Rokkas
Kostantinos
K
Constantinides
Costas
C
Christeas
Nikolaos
N
Flaris
Nikolaos
N
Voudoukis
Theodore
T
Scopa
Chrisoula D
CD
Perimenis
Petros
P
Filos
Kriton S
KS
Nikiforidis
George C
GC
Stolzenburg
Jens-Uwe
JU
Siablis
Dimitrios
D
D000818:Animals; D005260:Female; D009403:Nephrostomy, Percutaneous; D017239:Paclitaxel; D011859:Radiography; D013193:Stainless Steel; D015607:Stents / Q000009:adverse effects; D034421:Sus scrofa; D014513:Ureter / Q000000981:diagnostic imaging / Q000473:pathology; D014517:Ureteral Obstruction / Q000000981:diagnostic imaging / Q000628:therapy
D013193:Stainless Steel; D017239:Paclitaxel