CardioVascular and Interventional Radiology

© Springer-Verlag New York, Inc. 2002 Published Online: 5 December 2002

Cardiovasc Intervent Radiol (2003) 26:85– 87 DOI: 10.1007/s00270-002-1962-5

Renal Transplant Ureteral Stenosis: Treatment by Self-Expanding Metallic Stent Murat Cantasdemir,1 Fatih Kantarci,1 Furuzan Numan,1 Ismail Mihmanli,1 Betul Kalender2 1 2

Department of Radiology, Istanbul University Cerrahpasa Medical Faculty, 34300 K.M.Pasa, Istanbul, Turkey Department of Nephrology, Istanbul University Cerrahpasa Medical Faculty, Istanbul, Turkey

Abstract

Ureteral obstruction occurs in 1–10% of renal transplant patients [1]. The development of balloon catheters, stents and advances in percutaneous endourology has made percutaneous transluminal treatment of ureteral strictures a safe and effective procedure. Metallic stents have recently been used in the management of benign ureteral strictures unresponsive to balloon dilation [2, 3]. We report the successful treatment of a distal ureteral stricture resistant to balloon dilation with placement of a metallic selfexpanding Memotherm stent in a renal transplant patient.

Under ultrasound guidance the middle calyx of the transplanted kidney was punctured percutaneously. Antegrade pyelography demonstrated a 4 cm long stenosis in the distal segment of the ureter leading to obstruction (Fig. 1A, B). The length of the obstructed segment was measured by a guidewire with metric (cm) markers and an external chart. Balloon dilation was performed twice at 3 week intervals via the antegrade percutaneous route. We observed significant waisting on the inflating balloon on each balloon dilation initially, and then the balloon fully expanded during the dilation procedures. An 8 Fr internal– external drainage catheter (Chole-cath Biliary drainage set, 8 Fr ⫻ 50 cm, with P tip, Uresil, IL, USA) was placed with its distal end in the bladder. Four months after the first radiologic intervention, control antegrade pyelography demonstrated that ureteral stenosis persisted and that the stenosis was resistant to the previous dilations. The patient refused any kind of surgical approach, despite the explanation that surgery is the correct treatment. Metallic stent insertion was then planned. Through a stiff guidewire a 6 mm ⫻ 6 cm Memotherm self-expanding metallic stent (Bard Lab, France) was inserted via an antegrade percutaneous approach including the bladder entrance of the ureter (Fig. 1C). It was expanded by balloon dilation catheter after deployment, despite its selfexpanding property. The location of the stent was assessed by control antegrade pyelography. It was seen that the stent location was appropriate, there was no migration or dislocation and luminal patency was restored. Ureteral peristalsis was seen under fluoroscopy. An 8 Fr internal– external drainage catheter was left in place, which was removed 3 weeks later. There were no procedure-related complications. After a follow-up of 24 months at 3 month intervals ultrasonographic examination revealed normal findings with serum creatinine levels below 2 mg/dl.

Case Report

Discussion

A 28-year-old man who was on hemodialysis treatment received a livingdonor renal transplant in February 1998 due to chronic pyelonephritis. Acute graft rejection developed on the fifth postoperative day, confirmed by biopsy, although the patient was on immunosuppressive treatment. The plasma creatinine level fell below 2 mg/dl and diuresis improved by the use of pulse steroid and Orthoclone-OKT 3 treatment. Due to probable infectious complications of this treatment the temporary silastic ureteral stent which had been inserted during the transplantation procedure was removed. Routine ultrasonographic examination at the sixth postoperative month demonstrated a grade II hydronephrosis, and scintigraphic examination revealed normal perfusion of the transplanted kidney with increased excretion time and obstruction unresponsive to 40 mg furosemide, indicative of obstructive uropathy. The creatinine level increased suddenly from 2 mg/dl to 6.3 mg/dl. Retrograde double J-catheter placement was attempted unsuccessfully under general anesthesia.

Urologic complications related to renal transplantation have decreased over the past 20 years from 10 –25% to 1–10%. This decrease has been attributed to advances in surgical techniques and the use of lower levels of steroids in the immunosuppressive regimens [4]. During the transplantation procedure the blood supply to the ureter and pelvis of the donor kidney is an important factor in the prevention of urologic complications. Ischemia is the most common cause of ureteral stenosis secondary to vascular insufficiency due to anastomosis techniques and excessive hilus dissection. Urinary leakage and subsequent formation of periureteral fibrosis may also lead to ureteral stenosis. The location of stenosis is mostly at the ureteropelvic junction, followed by the distal ureter, mid-ureter and proximal ureter [1]. Lieberman et al. [5] first described percutaneous antegrade balloon dilation and endoscopic placement of a temporary silastic stent for benign ureteral stenosis following renal transplantation. Since this first report there have been many studies on post-

We report the use of a metallic stent in a transplant ureteral stenosis. A 28-year-old man with chronic renal failure due to chronic pyelonephritis, who received a living-donor renal transplant, presented with transplant ureteral stenosis. The stenosis was unresponsive to balloon dilation and was treated by antegrade placement of a self-expanding Memotherm stent. The stented ureter stayed patent for 3 years. It may be reasonable to treat post-transplant ureteral stenosis resistant to balloon dilation with self-expanding metallic stents. However, long-term follow-up is required to evaluate the efficacy of this treatment. Key words: Kidney, transplantation—Stents and prostheses—Ureter, stenosis

Correspondence to: M. Cantasdemir; email: [email protected]

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Fig. 1. A, B Antegrade pyelography of the transplanted kidney demonstrates a dilated pelvicalyceal system and transplant ureter with tight distal ureter stenosis. C Stent placed in the distal ureter with contrast medium injection confirms patency of the segment with stent.

transplant ureteral stenosis treated by 6 –10 mm balloon dilation catheters and 8 –12 Fr temporary silastic stents [6, 7]. The procedural success rates after 1 year of follow-up were variable, ranging from 40% to 80%. The length of the stenosis, time after transplan-

M. Cantasdemir et al.: Renal Transplant Ureteral Stenosis

tation and ureteral vascular supply are the main factors affecting balloon dilation procedures. Generally stenosis of more than 2 cm is unresponsive to dilation. Long segment stenosis, failure of endoscopic procedures and vascular insufficiency are indications for surgical repair [6]. In our case, the ureteral stenosis was at the distal portion of the ureter and 4 cm long. Despite two sessions of antegrade percutaneous balloon dilation the ureteral stenosis did not respond to dilations, which was seen on antegrade pyelography. Since the patient refused surgical treatment we decided on stent placement. Self-expanding metallic stents are commonly used for vascular biliary stenosis. Recently, native kidney ureteral stenoses have been treated using metallic stents [8]. Herrero et al. [3] first reported the use of self-expanding metallic stents antegradely in the treatment of ureteral stenosis after renal transplantation as an alternative to open surgical repair. They used Wallstents in two cases, with a successful treatment of stenosis unresponsive to balloon dilation and placement of a double-J catheter. Peregrin and Lacha [2] used a Gianturco biliary Z-stent in a case of renal transplant ureteral stenosis. They stated that metallic stents could be used in short juxtavesical stenosis. Although in our case the stenotic segment was long, we successfully treated the stenosis with a single stent and single procedure, which might partly be due to the high elasticity and radial force of the Memotherm stent. Urothelial reaction may occur shortly after insertion of the prosthesis or it may be a late phenomenon. Complete occlusion of the stent by this urothelial reaction is via a hyperplastic reaction [3]. The use of stents in ureteral stenoses has been widely addressed and generally not recommended for the obvious reasons of progressive intimal hyperplasia and ultimate occlusion. This is particularly true in transplant ureteral stenoses. However, Lugmayr and Pauer [8] consider that if the metallic stent lies in contact with and is incorporated into the wall of the ureter, and if its lumen comes to be completely lined by urothelium, the stimulus for hyperplasia is eliminated. For that reason we expanded the metallic stent with balloon dilation catheter after deployment, despite its self-expanding property, to incorporate the stent into the ureter wall. In addition, at autopsy Peregrin and Lacha [2] found that the stent was largely covered by urothelium and there were no signs of hyperplasia. Also, Herrero et al. [3] did not observe urothelial hyperplasia during the follow-up period in their cases. Because our patient refused any surgical procedure, and there have been publicated reports of use of metallic stents in renal transplant ureteral stenosis as mentioned above, we performed metallic stent insertion as an alternative to surgery. On the 3 week control pyelogram after stent deployment there was no evidence of “early” urothelial reaction, with smooth luminal surfaces. During 3 years of follow-up at 3 months intervals we did not observe any pelvicalyceal ectasia by ultrasonography and the creatinine level was below 2 mg/dl. We think that during this period there was no significant urothelial reaction. In conclusion, every treatment modality has its own success and complication rates; therefore treatment must be individualized. We think that it may be reasonable to treat post-transplant ureteral stenoses resistant to balloon dilation with self-expanding metallic stents as an alternative to open surgical repair. However, long-term studies should be carried out to evaluate the efficacy of the treatment. References 1. Loughlin KR, Tilney NL, Richie JP (1984) Urologic complications in 718 renal transplant patients. Surgery 95:297–302 2. Peregrin JH, Lacha J (1998) Successful treatment of renal transplant

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ureter stenosis with use of the biliary Z stent. J Vasc Interv Radiol 9:741–742 3. Herrero JA, Lezana A, Gallego J, Maranes A, Prats D, Portoles J, Torrente J, Barrientos A (1996) Self expanding metallic stent in the treatment of ureteral obstruction after renal transplantation. Nephrol Dial Transplant 11:887– 889 4. Kinnaert P, Hall M, Janssen F, Vereerstraeten P, Toussaint G, Van Geertrudyen J (1985) Ureteral stenosis after renal transplantation: True incidence and long-term follow-up after surgical correction. J Urol 133:17–20 5. Lieberman SF, Keller FS, Barry JM, Rosch J (1982) Percutaneous

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antegrade transluminal ureteroplasty for renal allograft ureteral stenosis. J Urol 128:122–124 6. Beckmann CF, Roth RA, Bihrle W 3rd (1989) Dilation of benign ureteral strictures. Radiology 172:437– 441 7. Kim JC, Banner MP, Ramchandani P, Grossman RA, Pollack HM (1993) Balloon dilation of ureteral strictures after renal transplantation. Radiology 186:717–722 8. Lugmayr H, Pauer W (1992) Self-expanding metal stents for palliative treatment of malignant ureteral obstruction. AJR Am J Roentgenol 159:1091–1094