Vesico-ureteral reflux in pediatric kidney transplants: clinical relevance to graft and patient outcome

Acute kidney injury caused by ureteral obstruction after Deflux® injection treatment for vesicoureteral reflux after pediatric kidney transplantation: a case report

BACKGROUND

Vesicoureteral reflux (VUR) after pediatric kidney transplantation (KT) is a frequent urologic complication. Endoscopic Deflux® injection is a treatment option. However, ureteral obstruction after Deflux® injection treatment is a potential complication that may have serious outcomes for patients who have undergone KT. We report a case of acute kidney injury (AKI) caused by ureteral obstruction with acute foreign body reaction immediately after Deflux® injection treatment for VUR after transplantation.

CASE PRESENTATION

We encountered a 5-year-old boy who underwent living-donor KT at age 4 years because of end-stage kidney disease caused by posterior urethral valves. At 4 months after KT, VUR (grade IV) and bladder dysfunction worsening were detected by voiding cystourethrography. A second febrile urinary tract infection (UTI) was treated with endoscopic Deflux® injection in the neo-orifice of the transplanted kidney after 2 weeks of antimicrobial therapy. Postoperatively, the patient experienced a temporary decrease in urine output. Increased creatinine was observed on postoperative day 1. The renal pelvis was more dilated than it was preoperatively, and ureteral dilatation was observed. A bulge associated with Deflux® injection, consistent with the injection site, was observed in the bladder. Additionally, because the graft function continued to decline, AKI associated with ureteral obstruction after Deflux® injection treatment was diagnosed, and a ureteral stent was placed on postoperative day 4. The graft function gradually recovered. Four months later, the ureteral stent was removed. Exacerbation of hydronephrosis of the transplanted kidney was not observed, and the graft function was stable. Although the patient experienced residual VUR after KT, excretion control was continued and UTI recurrence was not observed.

CONCLUSIONS

Ureteral obstruction after Deflux® injection treatment for VUR after transplantation is a serious complication; therefore, treatment indications and timing should be carefully considered.

Role of vesicoureteral reflux on pediatric kidney allograft function

BACKGROUND

Vesicoureteral reflux (VUR) is a common urologic complication of pediatric kidney transplant, though there is little data on the effect of VUR on histologic graft changes or graft survival.

METHODS

All pediatric patients who received a kidney transplant from 2007 to 2020 were selected for retrospective chart review. All participants underwent a voiding cystourethrogram (VCUG) at a 6-month post-transplant. Patients were then categorized into two groups based on vesicoureteral reflux grade: no/low-grade VUR (grades 0-2) and high-grade VUR (grades 3-5). Outcomes collected included graft failure rates, graft function, urinary tract infections (UTIs), proteinuria, and Banff scores at 3- and 12-month post-transplant surveillance kidney biopsies.

RESULTS

There were 74 pediatric patients who received a kidney transplant in the designated time-period, and of those 39 had no/low-grade VUR and 35 had high-grade VUR. There was no difference in graft failure among the two groups over time when stratified for age (p = 0.389, CI 0.53-5.08). Patients with high grade VUR had a higher risk of UTI development overall (RR 1.89, 95%CI 1-3.6, p = 0.041), mostly accounted for from increased development of febrile UTI (RR 1.66, 95%CI 1.1-2.6, p = 0.038).

CONCLUSIONS

Unselected pediatric kidney transplant recipients with high-grade vesicoureteral reflux on VCUG at a 6-month post-kidney transplant are more likely to have febrile UTI compared to those in the low-grade VUR group. There is no difference in graft survival among the two groups.

Current management of symptomatic vesicoureteral reflux in pediatric kidney transplantation-A European survey among surgical transplant professionals

BACKGROUND

Vesicoureteral reflux (VUR) is common in children and adolescents undergoing kidney transplantation (KTx) and may adversely affect allograft kidney function.

METHODS

To explore the current management of symptomatic native and allograft VUR in pediatric KTx recipients, an online survey was distributed to European surgical transplant professionals.

RESULTS

Surgeons from 40 pediatric KTx centers in 18 countries participated in this survey. Symptomatic native kidney VUR was treated before or during KTx by 68% of the centers (all/selected patients: 33%/67%; before/during KTx: 89%/11%), with a preference for endoscopic treatment (59%). At KTx, 90% favored an anti-reflux ureteral reimplantation procedure (extravesical/transvesical approach: 92%/8%; preferred extravesical technique: Lich-Gregoir [85%]). Management strategies for symptomatic allograft VUR included surgical repair (90%), continuous antibiotic prophylaxis (51%), bladder training (49%), or noninterventional surveillance (21%). Redo ureteral implantation and endoscopic intervention for allograft VUR were equally reported (51%/49%).

CONCLUSIONS

This survey shows uniformity in some surgical aspects of the pediatric KTx procedure. However, with regard to VUR, there is a significant variation in practice patterns that need to be addressed by future well-designed and prospective studies. In this way, more robust data could be translated into consensus guidelines for a more standardized and evidence-based management of this common condition in pediatric KTx.

Vesico-ureteric reflux in children and young people undergoing kidney transplantation

Vesico-ureteric reflux (VUR) into transplanted kidneys in children and young people is a common occurrence, found in 19 to 60% of those who had an anti-reflux procedure and up to 79% in the absence of such a procedure. While VUR is unlikely to be of concern without evidence of symptomatic urinary tract infections, less certainty exists regarding outcomes when the VUR is associated with urinary tract infection (UTI) and transplant pyelonephritis. Issues explored will include additional risk factors that might predispose to UTI, any effect of pyelonephritis on acute and long-term kidney allograft function and practical strategies that may reduce the prevalence of infection.

Vesicoureteral Reflux Causes Interstitial Inflammation in Pediatric Kidney Allograft: A Clinicopathological Analysis of 1-Year Protocol Biopsies

INTRODUCTION

At present, there is limited evidence of the histological impact of vesicoureteral reflux (VUR) on pediatric kidney allografts. In this study, we aimed to investigate the relationship between VUR diagnosed by voiding cystourethrography (VCUG) and 1-year protocol biopsy results.

METHODS

One hundred thirty-eight pediatric kidney transplantations were performed in Toho University Omori Medical Center between 2009 and 2019. We included 87 pediatric transplant recipients who were evaluated for VUR by VCUG prior to or at the time of the 1-year protocol biopsy and underwent a 1-year protocol biopsy after transplantation. We evaluated the clinicopathological findings of the VUR and non-VUR groups, and histological scores were evaluated using the Banff score. Tamm-Horsfall protein (THP) within the interstitium was identified by light microscopy.

RESULTS

Of the 87 transplant recipients, 18 cases (20.7%) were diagnosed with VUR by VCUG. The clinical background and findings were not significantly different between the VUR and non-VUR groups. The pathological findings revealed a significantly higher Banff total interstitial inflammation (ti) score in the VUR group than in the non-VUR group. Multivariate analysis indicated a significant relationship between the Banff ti score and THP within the interstitium, and VUR. The 3-year protocol biopsy results (n = 68) revealed a significantly higher Banff interstitial fibrosis (ci) score in the VUR group than in the non-VUR group.

CONCLUSION

VUR caused interstitial fibrosis in the 1-year pediatric protocol biopsies, and interstitial inflammation at the 1-year protocol biopsy may affect interstitial fibrosis at the 3-year protocol biopsy.

Treatment of Vesicoureteral Reflux Detected After Renal Transplant in Pediatric Patients: A Single-Center Experience

OBJECTIVE

In children who undergo renal transplant, vesicoureteral reflux on the transplanted kidney is a serious complication that may result in organ loss. In this study, we aimed to evaluate the results of endoscopic and open surgical techniques in the treatment of patients with recurrent urinary tract infections and vesicoureteral reflux after renal transplant.

MATERIAL AND METHODS

The files of pediatric patients who underwent renal transplant in our hospital between January 2016 and January 2019 were evaluated retrospectively. In this single-center analysis, we investigated the incidence of vesicoureteral reflux in the kidney transplant recipients and the results of various approaches to treat it.

RESULTS

Eighty pediatric patients underwent renal transplant between January 2016 and January 2019. Fourteen of those patients (17.5%, 7 female and 7 male) were diagnosed with vesicoureteral reflux in the postoperative period. Twelve of 14 patients received endoscopic injections as the first treatment. Clinical or radiological success was achieved in 5 patients (5 of 15 injection treatments, 33%); in 4 patients (4/12, 33.3%) success was after the first endoscopic injection treatment, and in 1 patient (1/3, 33.3%) success was after the second injection. Meanwhile, clinical or radiological success was achieved in 6 of 7 patients who underwent redo ureteroneocystostomy (6/7, 85.7%).

CONCLUSION

Although symptomatic vesicoureteral reflux after renal transplant is rare in pediatric patients, it is an important cause of morbidity as it requires recurrent surgical procedures. Although endoscopic treatment is safe and minimally invasive, the success rate is lower than expected, and redo of ureteral reimplant may be required in most cases.

Increasing bladder capacity and vesicoureteral reflux in pediatric kidney transplant patients

OBJECTIVES

To investigate the frequency of vesicoureteral reflux, and the relationship of pretransplant decreased bladder capacity and post-transplant vesicoureteral reflux in children undergoing kidney transplantation.

METHODS

A voiding cystourethrography was carried out in 172 pediatric kidney transplantation recipients before, and 4 months after, transplantation to evaluate bladder capacity and vesicoureteral reflux. The correlation of post-transplant vesicoureteral reflux with pretransplant bladder capacity, vesicoureteral reflux in the native kidney and the method of ureteral reimplantation (intravesical/extravesical) was analyzed. Atrophic bladder was defined as having ≤50% functional bladder capacity (age in years + 2) × 25 (mL) or ≤150 mL in patients aged >10 years.

RESULTS

Bladder capacity increased remarkably after transplantation in both post-transplant vesicoureteral reflux- group (from 180 to 253 mL) and vesicoureteral reflux+ group (from 82 to 171 mL). Voiding cystourethrography showed vesicoureteral reflux in 12 cases of kidney transplantation (7%; grade 1: 2, grade 2: 3, grade 3: 7). Pretransplant atrophic bladder was an independent risk factor of post-transplant vesicoureteral reflux (P = 0.004, hazard ratio 9.5). There was no difference in renal function between the vesicoureteral reflux- group and vesicoureteral reflux+ group at 4 months to 5 years post-transplantation.

CONCLUSIONS

Pretransplant atrophic bladder is a risk factor of post-transplant vesicoureteral reflux in pediatric patients. However, bladder capacity can remarkably increase after transplantation, and kidney function in the post-transplant vesicoureteral reflux+ group is stable.

When does vesicoureteral reflux in pediatric kidney transplant patients need treatment?

PURPOSE

The treatment of VUR in children with UTI has changed significantly, due to studies showing that antibiotic prophylaxis does not decrease renal scarring. As children with kidney transplants are at higher risk for UTI, we investigated if select patients with renal transplant VUR could be managed without surgery.

MATERIALS AND METHODS

A total of 18 patients with VUR into their renal grafts were identified, and 319 patients underwent transplantation from 2006 to 2016. The cause for the detection of the VUR, treatment, and graft function was reviewed.

RESULTS

Six boys and 12 girls were identified, 13 of whom had grade 3 or 4 VUR into the renal graft. Nine patients presented with hydronephrosis or abnormal renal biopsy: eight were successfully managed with antibiotic prophylaxis and bladder training, one developed UTI and underwent Dx/HA subureteric injection. Nine patients presented with recurrent febrile UTI, only one was successfully managed without surgery. Only 2 of 9 (22%) patients who underwent Dx/HA injection had resolution of their reflux. Of the remaining seven, five required open ureteral reimplantation (two for obstruction), one lost the graft due to rejection, and one had significant hydronephrosis. eGFR was similar between the hydronephrosis, UTI, and abnormal renal biopsy groups at all times.

CONCLUSION

Patients with transplant VUR and recurrent febrile UTI are more likely to require surgical therapy, but the complication and failure rate for Dx/HA injection is significant. Patients with transplant VUR without febrile UTI can be successfully managed with bladder training and temporary antibiotic prophylaxis.

Renal Transplant in the Abnormal Bladder: Long-Term Follow-Up

OBJECTIVES

Normal urinary bladder stores urine at low pressure, does not leak, and completely empties by natural voiding. An abnormal bladder may be due to neurologic or urologic disorders that render the bladder of small capacity, of high storage pressure, or of poor compliance. The aim of this study was to determine the long-term outcomes of renal transplant in patients with abnormal bladders.

MATERIALS AND METHODS

We retrospectively compared 30 transplanted kidneys in 25 patients with abnormal bladders with a control group comprising 30 grafts transplanted simultaneously during the same period of time (1990-2014) in 30 patients without bladder abnormality. Patient demographics, graft function, survival, and postoperative complications were compared.

RESULTS

Patients with abnormal bladders received transplants at a younger age than the control group (32 ± 17 vs 47 ± 12 y; P <. 001). Graft survival was not significantly different between the study and the control groups at 1 (90% vs 97%; P = .30), 3 (88% vs 91%; P = .67), and 5 years (82% vs 87%; P = .68). On long-term follow-up (20 years), 19 grafts (63%) were functioning in the study group compared with 25 grafts (83%) in the control group, suggesting inferior survival in those with an abnormal bladder after the first 10 years of transplant. In the abnormal bladder group, there was higher incidence of urologic complications (93% vs 50%; P<.001).

CONCLUSIONS

Despite the earlier age at transplant, the previous urologic operations, and the high incidence of urinary tract infection after renal transplant, graft survival and functions after renal transplant were not significantly different between patients with abnormal and normal bladders over at least the first 10 years. Therefore, it is safe to transplant into abnormal bladders once they have been assessed, reconstructed if necessary, and managed appropriately.

Comparison of Surgical Correction Techniques for Post-Renal Transplantation Vesicoureteral Reflux

BACKGROUND

Symptomatic urinary tract infection (UTI) after renal transplantation (RT) is an important morbidity in transplant recipients and may cause pyelonephritis and sepsis. Surgical correction of high-grade vesicoureteral reflux (VUR) after RT is suggested, performing ureteral reimplantation or pyelo-ureteral/uretero-ureteral anastomosis. Recently, extravesical seromuscular tunnel lengthening techniques have been reported with favorable results and low complication rates.

METHODS

We retrospectively reviewed the charts of 38 patients with post-transplantation VUR who underwent reflux correction surgery. Patient characteristics were analyzed to compare our extravesical seromuscular tunnel lengthening technique with uretero-ureteral and pyelo-ureteral anastomosis techniques.

RESULTS

Twenty patients were treated with the extravesical approach (group I) and 18 patients by pyelo-ureteral or uretero-ureteral anastomosis with the use of native ureter (group II). Mean operative time was significantly shorter in group I than in group II (64.8 vs 110.1 min; P < .05), and mean duration of hospital stay after the operation also was shorter in group I (1.5 vs 5.1 d; P < .05). We determined persistent VUR in postoperative voiding cystouretrography in 2 patients (10%) in group I, but there was regression in VUR grades of all of the patients. There was no significant difference in postoperative number of UTI episodes and serum creatinine levels between the 2 groups.

CONCLUSIONS

Extravesical seromuscular tunnel lengthening is an effective and safe technique for post-transplantation VUR management.

National risk factors and estimated costs for redo ureteroneocystostomy after pediatric renal transplant

Approximately 800 pediatric renal transplants are performed annually in the United States. VUR or obstruction may cause graft failure requiring redo ureteroneocystostomy. We examined possible risk factors and cost using the PHIS national database. We examined the PHIS for 8.5 yr to determine the association between redo ureteroneocystostomy following pediatric renal transplant to demographics, comorbidities, GU conditions, insurance status, and hospital characteristics, and looked at relative costs using descriptive and comparative statistics. A total of 2390 pediatric renal transplants were identified, of which 69 (2.3%) underwent redo ureteroneocystostomy (median 11.6 months post-transplant). Risk factors for redo ureteroneocystostomy are younger age (p = 0.048), PUVs (p < 0.001), female gender (p = 0.005), race (p = 0.014), insurance type (p < 0.027), region (p = 0.045), and transplant surgery volume (p = 0.048). Redo ureteroneocystostomy after transplant does not significantly increase the overall cost of transplant (p = 0.175). We confirmed previous findings that younger age and PUVs increase the risk of post-transplant redo ureteroneocystostomy, with a five-yr plateau. We found an association with gender, race, insurance status, and hospital characteristics. Redo ureteroneocystostomy, which increases costs, does not statistically significantly increase overall cost of individual treatment in this database, although costs may be underreported.

A nipple-valve technique for ureteroneocystostomy in pediatric kidney transplantation

The ureteroneocystostomy in kidney transplantation can be performed with a variety of techniques. Over a 20-yr period, we utilized a technique of nipple-valve ureteroneocystostomy for the pediatric kidney transplants performed at our institution. The distal ureter is everted upon itself and anchored in place with four interrupted sutures to create a nipple valve, which is then inserted into the bladder and sewn mucosa-to-mucosa with the same sutures. The muscularis layer is closed around the ureter without tunneling and without routine ureteral stenting. After 109 transplants, patient survival was 97.2, 97.2, and 86.9% at one, five, and 10 yr, respectively. Graft survival was 91.7, 71.7, and 53.9% at one, five, and 10 yr, respectively. The most common cause of graft loss was acute or chronic rejection, seen in 75% of those experiencing graft loss. Two patients (1.8%) developed pyelonephritis in the transplanted kidney. Nipple-valve ureteroneocystostomy in pediatric kidney transplantation is a safe and simple method for performing the ureterovesical anastomosis with a low rate of pyelonephritis after transplantation.

Non-viral infections in children after renal transplantation

Renal transplantation has long been recognised as the gold standard treatment for children with end-stage renal failure. There has been an improvement over the years in patient and renal allograft survival because of improved immunosuppression, surgical techniques and living kidney donation. Despite reduced acute allograft rejection rates, non-viral infections continue to be a serious complication for paediatric renal transplant recipients (RTR). The risk of infections in RTR is determined by the pre-transplantation immunisation status, post-transplant exposure to potential pathogens and the amount of immunosuppression. The greatest risk of life-threatening and Cytomegalovirus infections is during the first 6 months post-transplant owing to a high immunosuppressive burden. The potential sources of bacterial infections are donor derived, transplant medium fluid, peritoneal and haemodialysis catheter and transplant ureteric stent. Urinary tract infections are frequent in patients with lower urinary tract dysfunction and can result in renal allograft damage. This review outlines the incidence, timing, risk factors, prevention and treatment of non-viral infections in paediatric RTR by critically reviewing current immunosuppressive regimens, their risk-benefit ratio in order to optimise renal allograft survival with reduced rates of rejection and infectious complications.

Urinary tract infection in renal transplantation

INTRODUCTION

Urinary tract infection (UTI), especially recurrent UTI, is a common problem, occurring in >75% of kidney transplant (KTX) recipients. UTI degrades the health-related quality of life and can impair graft function, potentially reducing graft and patient survival. As urologists are often involved in treating UTI after KTX, previous reports were searched to elucidate underlying causes, risk factors and treatment options, as well as recommendations for prophylaxis of UTI after KTX.

METHODS

Pubmed/Medline was searched and international guidelines and recommendations for prevention and treatment of UTI after KTX were also assessed.

RESULTS

Most studies on UTI after KTX have a small sample, and are descriptive and retrospective. Many transplant- and recipient-related risk factors have been identified. While asymptomatic bacteriuria is often treated, even though some studies advise against it, symptomatic UTI should be treated empirically after collecting urine for microbiological analysis, to avoid the development of transplant pyelonephritis with a high chance of urosepsis. The duration of treatment has not been determined in studies and recommendations refer to the treatment of complicated UTI in the non-transplant population. Prophylaxis has not been the focus of studies either.

CONCLUSION

UTI after KTX is still largely an under-represented field of study, despite many recipients developing UTI after KTX. Prospective studies on this topic are urgently needed.

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.

Correlations between pretransplant dialysis duration, bladder capacity, and prevalence of vesicoureteral reflux to the graft

BACKGROUND

Urinary bladder capacity is reduced in patients undergoing long-term dialysis, which may increase the risk of vesicoureteral reflux (VUR) to a transplanted kidney. This study investigated the correlations between dialysis duration, pretransplant and posttransplant bladder capacity, and prevalence of VUR to the graft.

METHODS

Voiding cystography was performed in 101 adult renal transplant recipients without neurogenic disorders immediately before and 1 year after transplantation to evaluate bladder capacity and VUR. Nonstented extravesical antireflux ureteroneocystostomy was performed in all patients.

RESULTS

The median dialysis duration and pretransplant bladder capacity were 32 months (range 1-426 months) and 120 mL (range 15-450 mL), and 21 patients (20.8%) underwent dialysis for more than 120 months, and 30 patients (29.7%) had a pretransplant bladder capacity of less than 80 mL. Dialysis duration was correlated with pretransplant bladder capacity (R=0.466, P<0.001). Bladder capacity expanded more than 6-fold from pretransplantation to posttransplantation, and all recipients had a bladder capacity greater than 150 mL at 1 year posttransplantation. Thirty patients had VUR to the graft. Dialysis duration longer than 60 months (P=0.021) and pretransplant bladder capacity of less than 130 mL (P=0.024) were associated with VUR. VUR was associated with lower graft function.

CONCLUSIONS

Although bladder capacity decreased because of long-term dialysis, it exceeded 150 mL at 1 year posttransplantation. A small bladder can be used in renal transplantation, but it may increase the risk of VUR.

Endoscopic application of dextranomer/hyaluronic acid copolymer in the treatment of vesico-ureteric reflux after renal transplantation

OBJECTIVE

• To evaluate the success of endoscopic dextranomer/hyaluronic acid copolymer (DHAC) application in the treatment of patients with recurrent urinary tract infections (UTIs) and vesico-ureteric reflux (VUR) into the transplanted graft after renal transplantation.

PATIENTS AND METHODS

• Between January 2008 and April 2009, 19 patients with recurrent UTIs presented VUR proven by voiding cystourethrography. • To correct VUR of the transplanted ureter, DHAC was injected endoscopically using hydrodistention technique. • Pre- and postoperative serum creatinine levels, the number of pre- and postoperative UTIs, postoperative complications and reflux resolution rate were recorded. The mean follow-up was 6.5 months.

RESULTS

• The average number of UTIs was reduced significantly from 4.89 (range 2-14) to 1.31 (range 0-4) on pre- and postoperative follow-up, respectively, of 6 months (P < 0.001). The success rate increased from 57.9% after the first injection to 78.9% after the second injection. • The remaining four patients with residual VUR received long-term low dose antibiotic prophylaxis. In total, two (10.5%) patients developed increasing creatinine levels postoperatively as a result of distal ureteral obstruction, and temporary urinary drainage was necessary in both patients.

CONCLUSIONS

• DHAC appears to be an efficient and minimal invasive method for treating VUR after renal transplantation with respect to short-term success. • Further investigation with a larger group of patients and longer follow-up is needed to evaluate the prolonged effect, as well as any potential side effects.

Renal transplantation in children: critical analysis of age related surgical complications

To determine age-related risk factors of urological and vascular complications. We performed a retrospective analysis of the data of 202 renal transplantations in 193 children between 1989 and 2007 at a single institution. Out of 193 grafts (combined renal and liver grafts were excluded), we observed urological complications in 42 cases (21.7%) leading to graft loss in one case and vascular complications in 27 cases (13.9%) leading to graft loss in seven. The urological complications were VUR (n=25, 12.4%), ureteral stricture (n=10, 5%), anastomotic leak (n=4, 2%), ureteral necrosis (n=2, 1%), and incrustative pyelitis (n=1, 0.5%). Vascular complications were arterial stricture (n=14, 7.2%), arterial thrombosis (n=4, 2%), venous thrombosis (n=2, 1%), and others (n=7). Donors aged less than six yr were a risk factor of vascular complications leading to graft loss (p=0.0001), whereas patients with PUV had more urological complications (p=0.001). Overall patient and graft survival is 93.1% and 84% at five yr, respectively. Surgical complications remain a major cause of graft loss (12%) and morbidity in children's kidney transplantation (38.9%). Young age of donors is the major risk factor of early graft loss as a result of vascular complication. However, donor selection based on age is limited by the shortage of organs.

Endoscopic treatment of symptomatic refluxing renal transplant ureteroneocystostomies in children

To present a multi-center experience with the use of Dx/HA copolymer for treatment of symptomatic refluxing renal transplant UNC in children. A multi-center, retrospective chart review was performed. Eleven patients with a mean age of eight yr underwent renal transplantation with an anti-refluxing UNC. Data were collected to determine the safety and effectiveness of the procedure and to identify possible predictors of success. Endoscopic treatment was successful in one of five males and five of six females, for an overall success rate of 54.5%. The etiology of renal failure was associated with success of treatment, with 4/6 (67%) patients with upper tract pathology demonstrating resolution of the VUR, as compared with one of three (33%) patients with lower tract pathology. Male patients had a higher incidence of lower tract pathology. No complications were associated with the endoscopic procedure. Endoscopic injection of Dx/HA remains a safe option for the treatment of symptomatic refluxing transplant UNC in children. Although the success rate is lower than that seen in the treatment of primary VUR, the minimally invasive nature and safety of this technique may offer advantages over open reconstruction of the refluxing transplant ureter.

Urinary tract infections in children after renal transplantation

Urinary tract infections (UTI) after pediatric kidney transplantation (KTX) are an important clinical problem and occur in 15-33% of patients. Febrile UTI, whether occurring in the transplanted kidney or the native kidney, should be differentiated from afebrile UTI. The latter may cause significant morbidity and is usually associated with acute graft dysfunction. Risk factors for (febrile) UTI include anatomical, functional, and demographic factors as well as baseline immunosuppression and foreign material, such as catheters and stents. Meticulous surveillance, diagnosis, and treatment of UTI is important to minimize acute morbidity and compromise of long-term graft function. In febrile UTI, parenteral antibiotics are usually indicated, although controlled data are not available. As most data concerning UTI have been accumulated retrospectively, future prospective studies have to be performed to clarify pathogenetic mechanisms and risk factors, improve prophylaxis and treatment, and ultimately optimize long-term renal graft survival.

Vesicoureteral reflux after kidney transplantation in children

We analyzed the frequency of vesicoureteral reflux and the factors that favor its appearance after kidney transplantation in pediatric patients. This retrospective analysis examined the prevalence of post-transplant vesicoureteral reflux in a total of 181 kidney transplants performed in children at our center between 1978 and 2004. In patients who required corrective surgery for this problem, we analyzed pretransplant residual diuresis, pretransplant pathology and post-transplant problems related to vesicoureteral reflux. We also analyzed form of presentation, whether reflux was to the graft or to the native kidney, degree of reflux, and surgical technique used to correct reflux. Ten patients (5.5%) needed surgery to correct reflux to the graft (nine children) or to the native kidney (one child). Reflux was manifested as urinary tract infection in six children and progressive graft failure in one. Urethrovesical disorders that favored vesicoureteral reflux were present in eight patients (non-compliance bladder, detrusor overactivity, posterior urethral valves, urethral stenosis). Lengthening the submucosal tunnel stopped urinary tract infections in all 10 patients, whereas six-month voiding cystourethrograms showed resolution in 8 patients and (only) reduction in the degree of reflux in two. The high percentage of post-transplant vesicoureteral reflux in pediatric patients were related with higher frequencies of ureterovesical pathology in children who received the transplant. Lengthening the submucosal ureteral tunnel vesicoureteral reflux was corrected in 80%. We recommend during implantation in children with pretransplant urethrovesical abnormality an initial technique, which utilizes a longer submucosal tunnel such as the Lich-Gregoir.

Redo Ureteroneocystostomy Using an Extravesical Approach in Pediatric Renal Transplant Patients With Reflux: A Retrospective Analysis and Description of Technique

PURPOSE

Vesicoureteral reflux and pyelonephritis following transplantation may significantly contribute to renal damage and premature graft loss. We report our retrospective experience with redo ureteral reimplantation of refluxing pediatric renal transplants and describe our surgical technique.

MATERIALS AND METHODS

We identified 20 children with a diagnosis of symptomatic post-transplant vesicoureteral reflux, of whom 16 underwent redo ureteral reimplantation. Patient characteristics including etiology of end stage renal disease, presenting symptoms, serum creatinine and postoperative followup were documented. The presence or absence of lower urinary tract dysfunction was documented and values between the 2 groups were analyzed for significance.

RESULTS

All 20 patients presented after assessment for a febrile urinary tract infection, and 35% had concurrent lower urinary tract dysfunction. Median interval between transplantation and vesicoureteral reflux diagnosis was 1.3 years, and mean vesicoureteral reflux grade was 3.2. Patients with lower urinary tract dysfunction presented significantly earlier and had a higher postoperative serum creatinine than those without lower urinary tract dysfunction (1.1 vs 1.7 years, p = 0.048). Redo reimplantation was performed in 94% of patients using an extravesical approach with ureteral stent placement. Seven of 16 patients underwent followup voiding cystourethrogram, with 5 demonstrating resolution and 2, both with lower urinary tract dysfunction, exhibiting persistent vesicoureteral reflux. At a mean followup of 3.6 years 25% of patients experienced recurrent pyelonephritis, while 75% were asymptomatic. One instance of anastomotic stricture occurred in a patient with lower urinary tract dysfunction.

CONCLUSIONS

Effective repair of post-transplantation vesicoureteral reflux can be performed using an extravesical technique, facilitated by preoperative ureteral stent placement. Patients with lower urinary tract dysfunction are likely to present earlier after transplantation than those without lower urinary tract dysfunction, and may have an increased risk of persistent vesicoureteral reflux and renal damage despite surgical correction.

Urological and Surgical Complications in 362 Consecutive Living Related Donor Kidney Transplantations

OBJECTIVE

The aim of this study is to review retrospectively the surgical and urological complications encountered in 362 cases of living related donor kidney transplantations (LRDTs).

MATERIAL AND METHODS

Between 1983 and 2002, 362 consecutive LRDTs were performed at our institution. The urological and surgical complications were determined in these cases.

RESULTS

Overall, urological and surgical complications were encountered in 57 (15.7%) of the renal transplants. Of the 362 patients, urological complications were detected in 29 of them (8.01%), including 5 urinary fistula (with 1 distal ureteral necrosis), 2 ureteric stenosis, 1 renal calculi, 8 symptomatic vesicoureteral reflux and 13 lymphocele requiring intervention. Vascular complications were developed in 5 patients such as renal vein thrombus in 1 and renal arterial stenosis in 4 cases. Wound infection was detected in 6 patients. Fourteen patients underwent surgical explorations due to perinephric hematoma during the early postoperative period. Renal allograft rupture due to accelerated rejection was developed in 2 cases. A lower segmental arterial injury occurred in 1 patient during the operation.

CONCLUSION

LRDT is an important treatment alternative for patients with end-stage renal disease. Many complications may occur after renal transplantations. Our rate of complications is within the range of the current literature. After a modification of our surgical technique, as not dissecting the external iliac artery, the number of lymphoceles has decreased dramatically and with using ureteric stents, we detected a significant decrease in urinary complication rates.

Urinary tract infections beyond the early post-transplant period in pediatric renal graft recipients

BACKGROUND

Urinary tract infection is a frequent bacterial complication after renal transplantation in adults and children, however there are only very limited data on children beyond the early post-transplant period. In this study we investigated urinary tract infections in pediatric outpatients who had received transplants more than six months previously. Incidence, risk factors and impact on short-term graft function were analyzed.

METHODS

47 children who had received a total of 58 allografts were analyzed between 1997 and 2000. At the time of analysis they had had their transplants for an average of 3.5 years (range 0.5-9.4). Urinary tract infection was defined as the presence of both significant bacteriuria (> 10(5) CFU/ml) and symptoms.

RESULTS

Of the 47 patients, 15 (32%) had from 1 to 7 urinary tract infections each. In total 35 infections were recorded. Median age at urinary tract infection was 5.5 years (range 1.8-24.2). Gender, donor source, immunosuppression and underlying disease (urologic vs non-urologic) did not influence the incidence of urinary tract infection. Creatinine but not C-reactive protein rose significantly during the infection.

CONCLUSIONS

Our data suggest that urinary tract infection remains a frequent but mostly benign complication in the pediatric transplant population, even beyond the early post-transplant period. More extended studies are needed to assess the long-term effects on graft function.

Cyclic voiding urosonography for detecting vesicoureteric reflux in renal transplant recipients

BACKGROUND

The clinical significance of vesicoureteric reflux (VUR) in renal transplant recipients remains controversial. Voiding urosonography (VUS), a new modality for detecting VUR, can be used in these patients. The sensitivity of X-ray and radionuclide cystography for detecting VUR may be improved with cyclic procedures. The aim of our study was to evaluate whether cyclic VUS is superior to the single-cycle procedure.

METHODS

Cyclic VUS was performed in 27 renal transplant recipients. Eight were children or adolescents and the remaining 19 recipients were adults. VUS was performed according to accepted guidelines. After the first micturition, the catheter was left in place and the entire procedure was repeated under the same conditions.

RESULTS

Both initial cycle and cyclic VUS detected 17 out of 27 (63%) VURs in the same patients. The sensitivity was not improved by cyclic VUS. However, there were differences between the initial cycle and cyclic VUS (P=0.028) when comparing the number of negative results and the grades of VURs detected. This difference was even more pronounced when analysing only positive results. In the initial cycle, five out of 17 (29%) VURs were grade III, compared with 10 out of 17 (59%) grade III VURs in the same patients using the cyclic procedure (P=0.008).

CONCLUSIONS

Cyclic VUS did not improve the detection sensitivity for VUR in our study. However, given that VUR grade may be important for the management of renal transplant recipients, the use of cyclic VUS may provide a useful diagnostic tool for these patients.

Vesicoureteral reflux after kidney transplantation in children

BACKGROUND

The prevalence and significance of vesicoureteral reflux (VUR) after kidney transplantation in adults varies between authors and there have been few reports in children.

METHODS

We conducted a retrospective study in a single-centre paediatric cohort. Fifty-five of the 84 children who underwent kidney transplantation over a 5-year period were checked with routine cystography after a median of 8 months post-transplantation. Graft function and urinary-tract infections were assessed during the first 6 years after transplantation.

RESULTS

VUR into the graft was present in 58% of the patients. Graft function and incidence of urinary-tract infections were similar in the two groups, independent of VUR. After having excluded infections attributed to the presence of a catheter, actuarial survival rates without pyelonephritis and without pyelonephritis following a first lower urinary-tract infection were worse in patients with VUR (P:=0.017 and P:=0.0039 respectively). None of the eight patients with VUR treated with antibiotic prophylaxis after a first acute pyelonephritis (APN) episode presented subsequent APN after 4.4+/-3.3 years on therapy.

CONCLUSIONS

VUR to the graft occurred in more than half paediatric renal transplant recipients. This condition was associated with an increased risk of APN. Long-term antibiotic prophylaxis seems to be able to prevent APN in transplanted children with VUR.