Initial experiment of self-expanding metal ureteral stent in recurrent ureteral stenosis after kidney transplantation.

Abstract

To the Editor: Ureteral stenosis (US) is one of the most common urologic complications after kidney transplantation (KT), and the incidence ranged from 2.6% to 15% among different transplant unit.1 Reoperation has a definite effect on US, but it is also associated with greater morbidity, prolonged recovery, and a higher risk of more serious complications including graft loss and perioperative mortality.2 Endourological approaches have become the first-line treatment due to its minimally invasive characteristics. Allium® ureteral stent is one of the new generation products of self-expanding metallic stents. It is a fully covered, self-expanding, large caliber metal stent. Here, we present our experience with the use of Allium® ureteral stent in the management of US after KT. We performed eight Allium® ureteral stent placement procedures from April 2019 to May 2020. This study was approved by Ethics Approval Committee of West China Hospital. All the five kidney transplants from deceased donors were performed after January 1, 2015, and these organs were donated from deceased patients. The main inclusion criterion was that the patients had experienced traditional stents placement and/or balloon dilatation at least two times, and cannot have or deny reoperation. This procedure was performed under general anesthesia. The ureters were contrasted anterogradely or retrogradely under fluoroscopy to show the location and length of ureteral stenosis. The ureteral balloon dilator was used to pass over the site of stenosis and inflated to 20 atm (1.72 MPa) for 3 min. Then, we positioned a 10 cm, 30Fr stent in the stricture segment and confirmed by fluoroscopy. Patient characteristics were shown in Table 1. The overall success rate was 87.5%. In our series, the creatinine levels of six patients were in the normal range before and after operation. Two patients had impaired renal function before procedure, and the preoperative creatinine levels were 154 and 255 umol/L, respectively. One month after stent insertion, the creatinine levels were 164 and 259 umol/L, respectively. The advantage of Allium® stents is that it can significantly reduce the frequency of stent replacement. The patients exchange traditional stents with a frequency of 3–6 months, which is a painful experience, and according to our follow-up, this stent has less stent-related symptoms and pain and less impact on life than traditional stents. In our cases, the longest follow-up was 17 months. Bahouth et al. showed that among the 92 patients with benign/malignant ureteral stricture treated with Allium® stent in a mean follow-up of 27 months, only 1 case had obstruction, 11 cases had stent migration.3 However, Salciccia et al reported one case of Allium® stent implantation for 36 months developed complete loss of renal function, probably because of the development of a long achalasic stretch of the ureter and reflux.4 Therefore, patients with metal stents should be followed up regularly. This is a small series of US patients receiving the treatment of Allium® ureteral stent. From our early experience, the use of this stent in US following KT is safe and feasible. The initial results are encouraging and suggest that they may be an effective alternative technique in these patients. The study was supported by the Natural Science Foundation of China (grant no. 81870513, 81470980 and 81600584) and 1.3.5 Project for Disciplines of Excellence, West China Hospital, Sichuan University (grant no. ZY2016104), Youth Researcher Funding of Sichuan University (grant no. 2017SCU11042), and Research Funding of Sichuan Health and Family Planning Commission (grant no. 17PJ159, 18PJ434 and 18PJ453), Sichuan Science and Technology Program (grant no. 2019YFH0151). The authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation.