Late ureteral stenosis following renal transplantation: risk factors and impact on patient and graft survival

Decrease in and management of urolithiasis after kidney transplantation

PURPOSE

Urolithiasis after kidney transplantation can involve several contributing factors and the treatment strategy is open to question. We determined the incidence and management of urolithiasis in kidney recipients.

MATERIALS AND METHODS

We retrospectively reviewed a single center series of 3,000 kidney graft recipients during 32 years to identify those with urolithiasis. We analyzed data by the prevalence per decade, including perioperative procedures (preoperative assessment, anastomosis type and urinary drainage) and long-term followup (urinary stenosis, time to presentation, size, site, treatment type, renal function and survival).

RESULTS

We identified 31 cases and noted a significant decrease in incidence from 2.1% to 0.6% during the 3 decades. Excluding 4 cases of donor in situ stones the mean time to diagnosis was 8.5 years. Surgical risk factors were ureteral obstruction in 41% of cases, infravesical obstruction in 14% and urinary-digestive anastomosis in 14%. A total of 12 cases (38%) were observed exclusively with 2 of spontaneous passage. With minor adaptations all mini-invasive procedures, including extracorporeal shock wave lithotripsy, endoscopy and percutaneous nephrolithotomy, were feasible in graft recipients. Antegrade procedures were facilitated by the ventral position of the graft. Eight patients (25%) were treated with open surgical ureteroureteral anastomosis.

CONCLUSIONS

Prevention with a perioperative Double-J® stent and early treatment of ureteral obstruction have decreased and stabilized the urolithiasis rate at around 0.6%. Careful surveillance or any currently available instrumental treatments of urinary stones can be valid options.

Ureteropyelostomy using the native ureter for the management of ureteric obstruction or symptomatic reflux following renal transplantation

OBJECTIVE

To evaluate the outcome of ureteropyelostomy using the native ureter for the management of ureteric obstruction or symptomatic reflux after renal transplantation.

MATERIALS AND METHODS

This is a single-center retrospective review of consecutive patients who underwent ureteropyelostomy after renal transplantation between the years 2000 and 2009. Ureteropyelostomy was performed using the ipsilateral native ureter. The native kidney was not removed. Patients' baseline characteristics, preceding interventions, and postprocedural outcomes were analyzed.

RESULTS

Ten patients underwent ureteropyelostomy after renal transplantation. All had initial Lich Gregoir ureterovesical anastomosis. Reasons for the reconstructive surgery were transplant ureteric stenosis in 8 patients or vesicoureteric reflux causing recurrent graft pyelonephritis in 2 patients. Median follow-up was 53 months (range 24-76). Postoperative complications included 3 patients who had transient anastomotic obstruction after removal of the double pigtail stent. They were managed with short-term ureteric restenting or nephrostomy tube insertion. In addition, 2 patients required delayed ipsilateral native nephrectomy because of infection. At last follow-up, all grafts remained unobstructed and free of infections.

CONCLUSION

Ureteropyelostomy using the native ureter for the management of transplant ureteric obstruction or symptomatic reflux is safe and provides good long-term preservation of graft function in selected patients.

The modified Barry technique to prevent vesicoureteric reflux in paediatric renal transplant recipients: initial recipient outcomes

OBJECTIVE

We present the initial clinical results of the 'modified Barry technique' for the prevention of VUR in paediatric renal transplant grafts. Ours is the only centre in the UK using this technique, as confirmed in a questionnaire developed in our department.

PATIENTS AND METHODS

We retrospectively analysed data of 15 paediatric renal transplant patients (operated June 2006-November 2009) who had their vesicoureteric anastomosis performed using the modified Barry technique with a 2-cm submucosal anti-reflux tunnel. The original Barry technique involved the creation of a 4-cm tunnel; this was modified by us to reduce the risk of ureteric stenosis.

RESULTS

At a median follow up of 23.7 months (6.3-39.4), the incidence of VUR was 7% (1/15). There was no evidence of postoperative urological complications, such as urinary leak, primary ureteric obstruction including anastomotic stricture/stenosis, transplant graft renal calculi and chronic rejection. At current follow up, graft and patient survival are 100%.

CONCLUSION

With the introduction of the modified Barry technique, the incidence of VUR in our series fell 10-fold to 7%, compared with our earlier study (P<0.0001), without any urological complications. Although the initial results are encouraging, larger patient numbers and longer follow up are required to validate this technique further.

Retrograde balloon dilation >10 weeks after renal transplantation for transplant ureter stenosis - our experience and review of the literature

Objective

Despite many efforts to prevent ureteric stenosis in a transplanted kidney, this complication occurs in 3–5% of renal transplant recipients. Balloon dilatation (BD) is a possible minimally invasive approach for treatment, but reports to date refer only to the antegrade approach; we analysed our experience with retrograde BD (RBD) and reviewed previous reports.

Patients and methods

From October 2008 to February 2011, eight patients after renal transplantation (RTX) underwent RBD for transplant ureteric stenosis at our hospital. We retrospectively analysed the outcome and reviewed previous reports.

Results

The eight recipients (five men and three women; median age 55 years, range 38–69) were treated with one or two RBDs for transplant ureteric stenosis. There were no complications. The median (range) time after RTX was 4.5 (2.5–11) months. Long-term success was only achieved in one recipient, while five patients were re-operated on (three with a new implant, two by replacement of transplanted ureter with ileum) after a median (range) of 2.8 (0.7–7.0) months after unsuccessful RBD(s). For two recipients the success remained unclear (one graft loss due to other reasons, one result pending). When the first RBD was unsuccessful there was no improvement with a second.

Conclusion

RBD is technically feasible, but our findings and the review of previous reports on antegrade ureteric dilatation suggest that the success rate is low when the ureter is dilated at ⩾10 weeks after RTX. From our results we cannot recommend RBD for transplant ureteric stenosis at ⩾10 weeks after RTX, while previous reports show favourable results of antegrade BD in the initial 3 months after RTX.

Increase of infectious complications in ABO-incompatible kidney transplant recipients--a single centre experience

BACKGROUND

Due to the shortage of deceased donors ABO-incompatible (ABOi) living kidney transplantation has become a popular alternative to deceased kidney transplantation. In recent years, recipient desensitization with a combination of anti-CD20 treatment (rituximab), antigen-specific immunoadsorptions (IA) and intravenous immunoglobulin (IVIG), led to promising short-term and intermediate-term results. However, little is known about the impact of this intensified desensitization protocol on the risk of surgical and infectious complications.

METHODS

We retrospectively analysed 21 consecutive recipients who underwent ABOi renal transplantation. Pre-transplant desensitization included administration of rituximab (375 mg/m(2)), mycophenolate mofetil (MMF), tacrolimus and prednisolone 4 weeks prior of scheduled transplantation as well as IA and IVIG. Forty-seven patients who underwent ABO-compatible (ABOc) renal transplantation served as the control group. Medical records and electronic databases were reviewed for patient and graft survival, renal function, rate of rejections, viral and bacterial infections as well as for surgical complications (SCs) post-transplantation.

RESULTS

All patients showed an immediate graft function. During a mean follow-up of 15.7 ± 8.3 months (interquartile range 11.9) patient survival was 95 and 98% in the ABOi and ABOc group, respectively. Allograft survival and function, as assessed by serum creatinine levels and calculated glomerular filtration rate at 1 year, did not differ between ABOi and ABOc recipients. Furthermore, the rate of biopsy-proven acute rejections was comparable between the two groups. However, there was a trend towards more SCs within the ABOi group (29 versus 11%, non-significant). In addition, the rate of viral infections including cytomegalovirus, Herpes simplex virus, Varicella zoster virus and polyoma virus was significantly increased among the ABOi recipients (50 versus 21%; P = 0.038) despite comparable tacrolimus trough levels and MMF and steroid doses.

CONCLUSIONS

Our results, in line with the extended experience of other groups, demonstrate favourable short-term allograft survival and function after ABOi renal transplantation after desensitization with antigen-specific IA, IVIG and rituximab. However, the intensified desensitization was associated with an increased risk of infectious complications. This observation prompted us to briefly escalate the desensitization protocol in ABOi kidney recipients in our centre.

Donor type does not influence the incidence of major urologic complications after kidney transplantation

BACKGROUND

There has been a marked recent increase in the proportion of kidneys transplanted from live donors (LD) and donors after cardiac death (DCD) compared with donors after brain death (DBD). The purpose of this study was to compare the incidence of major urologic complications (MUCs: urinary leak and ureteric stenosis [US]) in kidney transplants procured from LD, DCD, and DBD and to identify the factors associated with MUCs.

METHODS

We studied 901 consecutive renal transplants (LD: 181, DCD: 198, and DBD: 522) performed in the Cambridge Transplant Centre during 1998 to 2008 by retrieving data from a prospective, cross-audited database, and detailed case note review. An ureteroneocystostomy over a double pigtail ureteric stent was performed in all transplants, and ureteric stents were removed after approximately 6 weeks. All ureteric stenoses were treated by surgical reconstruction.

RESULTS

Three patients developed urine leak, and 21 developed US. There was no significant difference in the incidence of US in kidneys retrieved from LD (2.8%), DBD (1.7%), or DCD (3.5%; P=0.28). Recipients with US had a higher incidence of acute rejection (48% vs. 27%; hazard ratio 3.2, P=0.005) and urinary tract infections before the diagnosis of US (48% vs. 19%; hazard ratio 3.0, P=0.01). The incidence of delayed graft function (38% vs. 26%), cold ischemia times (12.9 vs. 13.5 hr), and graft survival was not significantly associated with US.

CONCLUSIONS

The incidence of MUCs is similar in kidneys transplanted from LD, DCD, and DBD. When complications do occur, they can be treated successfully by surgical reconstruction.

Scrotal herniation of the ureter: a rare late complication after renal transplantation

Although late ureteral obstruction represents the most frequent urologic complication after renal transplantation, its etiology remains poorly understood. Benign prostatic hyperplasia (BPH) is the most common cause of urinary tract obstruction in the adult male population, but information regarding BPH epidemiology and its impact on clinical outcomes are lacking. We herein have described a case of ureteral herniation into the scrotum, secondary to concomitant upper and lower urinary tract obstruction: namely, BPH and ureterovesical junction stenosis causing massive urine retention and acute renal failure. The simultaneous presence of the 2 lesions rendered the diagnosis difficult. In addition, urine outflow responsible for bladder outlet obstruction resumed after transurethral resection of the prostate (TURP). The hydroureteronephrosis, which persisted after the TURP resolved only after positioning a double J stent, but renal function did not normalize. Attention must be paid to BPH in the differential diagnosis of urinary tract obstruction. Stenosis of the ureterovesical junction may occur very late after transplantation.