Effect of ureteric stents on urological infection and graft function following renal transplantation

Routine Kidney Graft Ultrasound After Elective Ureteric Stent Removal: Does it Help?

Transplantation (KTx) is considered to be the best renal replacement therapy, and improving its outcomes remains a primary challenge. KTx ureteral stenting has been used to prevent urological complications, but there is no consensus on the timing of stent removal, and literature regarding routine ultrasonography after ureteric stent removal (RUSUS) to detect complications is lacking. Point-of-care ultrasound has been gaining drive in the medical community in recent years, including nephrologists. We aimed to define the incidence of urological complications diagnosed with RUSUS, if those findings changed patient's management and ultrasound utility. Contrary to previously published data, in our cohort RUSUS allowed a timely diagnosis and early treatment of urological complications, a key factor for successful transplantation. KTx point-of-care ultrasound is a cost-effective and reproducible test that provides relevant information to guide clinical decisions, seeming most efficient when performed approximately 2 weeks post ureteral stent removal. Interventional nephrologists can promptly perform these examinations, reducing waiting times and improving graft and patient's survival.

Recommendations of the AFU Infectious Diseases Committee on the prevention, diagnosis and treatment of infections of endo-ureteral equipment

INTRODUCTION

No recent national guidelines exist regarding the management of urinary tract infections (UTIs) in the presence of ureteral stent. This situation could lead to discrepancies in clinical management and less opportunity for a favorable patient's outcome.

METHODS

All available data published on Medline® between 1998 and 2018 were systematically searched and reviewed. All papers assessing adult patients carrying ureteral stent were included for analysis. After studies critical analysis, national guidelines for clinical management were elaborated in order to answer clinical questions.

RESULTS

A total of 451 articles were identified, of which 58 have been included. The prevalence of urinary tract infections in the presence of ureteral stent remains unknown. After 3 months, all endo-ureteral devices were colonized on microbiological study. These patients also presented a positive urine culture in 25 to 70% of the cases, often polymicrobial. Staphylococci, E. coli, Klebsiella, Pseudomonas, Enterococcus and Candida were the commonest micro-organisms responsible for urinary colonization or infection. The risk of UTI on endo-ureteral devices seemed higher the longer it stayed implanted. There is no justification in the literature to recommend a systematic change of endo-ureteral devices following a urinary tract infection.

DISCUSSION

The existing literature is rich but of poor methodological quality, and therefore does not allow to draw robust conclusions. The greatest difficulty faced in this work was to accurately differentiate urinary colonizations from true infections, including clinical symptoms and not only microbiological results.

CONCLUSION

These guidelines propose a standardized management of such common clinical situations. Well-designed studies are needed to upgrade the level of evidence of these guidelines.

No evidence for the need of a routine renal transplant ultrasound after elective transplant ureteric stent removal-A retrospective cohort study

Transplant ureteric stent insertion reduces the incidence of MUCs, but it is not known whether routine PSRGU is needed to detect unmasked MUCs. This study evaluated whether routine PSRGU in the pRTR is a useful tool to identify MUCs before they become clinically apparent. A retrospective analysis was undertaken of the clinical outcomes following elective stent removal from pediatric kidney-only transplant recipients at two London centers between 2012 and 2016. Our policy was to perform PSRGU either routinely or urgently if there were concerning symptoms or biochemical evidence of renal allograft dysfunction. Elective stent removal was performed in 86% (97 of 113 pRTR), and 75 (77%) of whom had routine PSRGU at a median (IQR) of 6 (2-8) days after stent removal. There were changes to management in 3 (4%) of pRTR with PSRGU identifying no MUC. Nineteen patients (25%) had urgent PSRGU, most commonly due to renal allograft dysfunction, at a median (IQR) of 5.5 (2.7-12.3) days after stent removal. Of these, two pRTR required ureteric intervention. For our current practice of removing transplant stents at 4-6 weeks post-transplantation, our study has found no evidence to support routine PSRGU after elective stent removal.

Managing recurrent urinary tract infections in kidney transplant patients

INTRODUCTION

Recurrent urinary tract infections (UTI) are a common clinical problem in kidney transplant recipients. Due to the complex urological anatomy derived from the implantation of the kidney graft, the spectrum of the disease and the broad underlying pathophysiological mechanisms. Recurrent UTI worsen the quality of life, decrease the graft survival and increase the costs of kidney transplantation. Areas covered: In this review, we describe the definitions, clinical characteristics, pathophysiological mechanisms and microbiology of recurrent urinary tract infections in kidney transplantations. The actual published literature on the management of recurrent urinary tract infections is based on case series, observational cohorts and very few clinical trials. In this review, the available evidence is compiled to propose evidence-based strategies to manage these complex cases. Expert commentary: The management of recurrent urinary tract infections in kidney transplant patients requires a proper diagnosis of the underlying mechanism. Early identification of structural or functional urological abnormalities, potentially amenable for surgical correction, is crucial for a successful management. The use of antibiotics to prevent recurrent infections should be carefully evaluated to avoid side effects and emergence of antibiotic-resistant microorganisms.

Duplicated Ureters in Transplantation-A Single-center, Retrospective Study

BACKGROUND

Kidney transplantation remains the best therapeutic option for chronic renal failure. The objective of the study was to evaluate the impact of ureteral duplication in donor kidneys on transplantation outcome.

METHODS

In this study we performed a retrospective analysis of 75 patients who had undergone renal transplantation. The evaluated parameters included frequency of occurrence and risk of reoperation and graftectomy, mortality, as well as dependency of early and long-term graft function on pyelocaliceal system duplication.

RESULTS

Ureteral duplication was associated with more frequent double J stent catheter implantation (P < .05). There was no relationship detected between ureteral duplication, number of operations performed, and risk of graftectomy (P > .05). Early graft function with 2 ureters was similar to that of grafts with a single pyelocaliceal system. The long-term results were also comparable.

CONCLUSION

Ureteral duplication should not be considered a contraindication for renal transplantation.

How to stent the ureter after kidney transplantation in children?-A comparison of two methods of urinary drainage

Ureteral stenting after pediatric renal transplantation serves to prevent obstruction and urinary leakage, but can also cause complications. This study compares the complication rates of both methods. Data were retrospectively collected at Erasmus MC, Rotterdam, the Netherlands (splint group, n = 61) and Hospital for Sick Children, Toronto, Canada (JJ catheter group, n = 50). Outcome measures included urological interventions and incidence of UTIs during the first 3 months post-transplantation. The splint was removed after a median of 9 (IQR 8-12), the JJ catheter after 42 (IQR 36-50) days. Seven (11.5%) children in the splint group needed at least one urological re-intervention versus two in the JJ catheter group (P-value .20). UTIs developed in 19 children (31.1%) in the splint group and in twenty-five (50.0%) children in the JJ catheter group (P-value .04), with a total number of 27 vs. 57 UTIs (P-value .02). Nine (33.3%) vs. 35 (61.4%) of these, respectively, occurred during the presence of the splint (P-value <.001). Children with a JJ catheter developed more UTIs than children with a splint; the latter, however, tended to require more re-interventions. Modification of either method is needed to find the best way to stent the ureter.

The Utility of Routine Ultrasound Imaging after Elective Transplant Ureteric Stent Removal

Background. Ureteric stent insertion during kidney transplantation reduces the incidence of major urological complications (MUCs). We evaluated whether routine poststent removal graft ultrasonography (PSRGU) was useful in detecting MUCs before they became clinically or biochemically apparent. Methods. A retrospective analysis was undertaken of clinical outcomes following elective stent removals from adult single renal transplant recipients (sRTRs) at our centre between 1 January 2011 and 31 December 2013. Results. Elective stent removal was performed for 338 sRTRs. Of these patients, 222 had routine PSRGU (median (IQR) days after stent removal = 18 (11–31)), 79 had urgent PSRGU due to clinical or biochemical indications, 12 had CT imaging, and 25 had no further renal imaging. Of the 222 sRTRs who underwent routine PSRGU, 210 (94.6%) had no change of management, three (1.4%) required repeat imaging only, and eight patients (3.6%) had incidental (nonureteric) findings. One patient (0.5%) had nephrostomy insertion as a result of routine PSRGU findings, but no ureteric stenosis was identified. Of 79 patients having urgent PSRGU after elective stent removal, three patients required transplant ureteric reimplantation. Conclusions. This analysis found no evidence that routine PSRGU at two to three weeks after elective stent removal provides any added value beyond standard clinical and biochemical monitoring.

Management of urinary tract infection in solid organ transplant recipients: Consensus statement of the Group for the Study of Infection in Transplant Recipients (GESITRA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) and the Spanish Network for Research in Infectious Diseases (REIPI)

BACKGROUND

Urinary tract infections (UTIs) are one of the most common infections in solid organ transplant (SOT) recipients.

METHODS

Experienced SOT researchers and clinicians have developed and implemented this consensus document in support of the optimal management of these patients. A systematic review was conducted, and evidence levels based on the available literature are given for each recommendation. This article was written in accordance with international recommendations on consensus statements and the recommendations of the Appraisal of Guidelines for Research and Evaluation II (AGREE II).

RESULTS

Recommendations are provided on the management of asymptomatic bacteriuria, and prophylaxis and treatment of UTI in SOT recipients. The diagnostic-therapeutic management of recurrent UTI and the role of infection in kidney graft rejection or dysfunction are reviewed. Finally, recommendations on antimicrobials and immunosuppressant interactions are also included.

CONCLUSIONS

The latest scientific information on UTI in SOT is incorporated in this consensus document.

Xenotransplantation of uterine leiomyoma in Wistar rats: a pilot study

OBJECTIVE

To evaluate whether xenografts derived from hysterectomized patients would implant successfully and lead to uterine leiomyoma in Wistar rats.

STUDY DESIGN

This experimental study examined six female Wistar rats implanted with uterine leiomyoma obtained from patients who underwent hysterectomies at the gynecological surgery service of the HUUFMA. The rats were divided into two groups. Group I consisted of three rats in which the uterine leiomyoma had been implanted in the parietal peritoneum, and group II consisted of three rats in which the uterine leiomyoma was implanted in the subcutaneous tissue. The immunosuppressant mycophenolate mofetil (MMF) was administered orally by gavage (at a dose of 40 mg/kg of body weight) to prevent transplant rejection starting 15 days before the transplant and continuing throughout the entire experiment. After four weeks, necrosis and neovascularization were evaluated histologically in both groups and were classified as either absent or present. Lymphocytic inflammatory infiltration was also examined and classified as mild, moderate or intense (by hematoxylin and eosin staining), and fibrosis was classified as grade I-III (by Masson's trichrome staining).

RESULTS

Necrosis was absent from all three rats in group I and was observed in only one rat from group II. Neovascularization was present in two rats from group I and in only one rat from group II. The lymphocytic inflammatory infiltrate was mild in two rats and moderate in one rat from group I, and it was moderate in two rats and intense in one rat from group II. Two rats from group 1 exhibited grade III fibrosis, and one rat presented grade I fibrosis. In group II, two rats presented grade I fibrosis and one rat had grade II fibrosis. When necrosis and neovascularization were evaluated as variables, group I demonstrated greater evidence of successful implantation when compared to group II, indicating that the peritoneal implantation technique produces better results than the subcutaneous approach (p=0.039).

CONCLUSION

This study demonstrates that the xenotransplantation of uterine leiomyoma into the parietal peritoneum is more effective than the xenotransplantation of uterine leiomyoma into the subcutaneous tissue, and it describes a promising new model for the study of leiomyoma in vivo.

Ureterovesical anastomotic techniques for kidney transplantation: a systematic review and meta-analysis

No consensus exists about which ureterovesical anastomosis technique to use for kidney transplantation. The aim of this systematic review was to compare the existing techniques in relation to the risk of urological complications. All studies that compared ureterovesical anastomotic techniques in kidney transplantation were included. Study endpoints were urinary leakage, ureteral stricture, vesicoureteral reflux and hematuria. Subanalyses of stented and nonstented techniques were performed. Two randomized clinical trials and 24 observational studies were included. Meta-analyses were performed on the Lich-Gregoir (LG) versus Politano-Leadbetter (PL) techniques and LG versus U-stitch (U) techniques. Compared with the PL technique, the LG technique had a significantly lower prevalence of urinary leakage (risk ratio (RR): 0.47, 95% confidence interval (CI): 0.30 to 0.75) and a significantly lower prevalence of hematuria when compared with both PL and U techniques (RR: 0.28, 95% CI: 0.16 to 0.49 and RR: 0.23, 95% CI: 0.11 to 0.50, respectively), regardless of ureteral stenting. There was no difference in the prevalence of ureteral strictures or vesicoureteral reflux between the various techniques. Of the three most frequently used ureterovesical anastomotic techniques, the LG technique results in fewer urological complications than the PL and U techniques.