Urological Consequences following Renal Transplantation: A Review of the Literature

Observations on hydronephrosis after pig kidney transplantation in baboons

We have seen hydronephrosis (obstructive nephropathy) at necropsy in 3 of 11 (21%) genetically-engineered pig kidneys that functioned in baboons for >36 days, even when the clinical and histopathological features of rejection were minimal. We briefly report one such case and illustrate the macroscopic and microscopic appearances of such a kidney and ureter. The causes of the observed changes remain uncertain. In our small experience, there seems to be no correlation between the development of hydronephrosis and (i) the surgical technique, (ii) the genotype of the pig, (iii) the length of the pig ureter, or (iv) the immunosuppressive and anti-inflammatory therapy administered. We suggest that the distal ureteric thickening may be the result of an inflammatory response. In two cases, we resolved the problem by carrying out a secondary side-to-side anastomosis between the proximal pig ureter and the baboon bladder.

Relationship between early proteinuria and long term outcome of kidney transplanted patients from different decades of donor age

Background

Proteinuria after kidney transplantation portends a worse graft survival. However the magnitude of proteinuria related to patient and graft survival and its correlation with donor and recipient characteristics are poorly explored.

Methods

This study investigated the impact of post transplant proteinuria in the first year in 1127 kidney transplants analyzing the impact of different donor ages. Proteinuria cut off was set at 0.5 g/day.

Results

Transplants with proteinuria > 0.5 g/day correlated with poor graft and patient outcome in all donor age groups. In addition, 6-month-1-year proteinuria increase was significantly associated with graft outcome, especially with donors > 60 years old (p <  0.05; Odd Ratio 1.8). 1-year graft function (eGFR < or ≥ 44 ml/min) had similar impact to proteinuria (≥ 0.5 g/day) on graft failure (Hazard Ratio 2.77 vs Hazard Ratio 2.46). Low-grade proteinuria (0.2–0.5 g/day) demonstrated a trend for worse graft survival with increasing donor age. Also in kidney-paired analysis proteinuria ≥0.5 effect was more significant with donors > 50 years old (Odd Ratio 2.3).

Conclusions

Post-transplant proteinuria was increasingly harmful with older donor age. Proteinuria ≥0.5 g/day correlates with worse outcomes in all transplanted patients. Prognostic value of proteinuria and eGFR for graft and patient survival was comparable and these two variables remain significant risk factors even in a multivariate model that take into consideration the most important clinical variables (donor age, rejection, delayed graft function and cytomegalovirus viremia among others).

Is delayed graft function associated with ureteral stenosis in the kidney transplant recipient? A case-control study

INTRODUCTION

Ureteral stricture (US) in the kidney transplant recipient is a rare complication that can lead to morbidity and graft loss. Risk factor recognition is crucial in the prevention and management of this entity. Delayed graft function (DGF), as defined by the need for dialysis in the first week after transplantation, has been proposed as a risk factor in previous studies. Our objective is to determine the impact of DGF in US development in kidney transplant patients.

METHODS

We designed a matched case-control study. US cases in kidney transplant recipients were identified in the 2008-2017 period. We defined US as the rise in serum creatinine associated with findings suggesting obstruction in ultrasound, scintigraphy, or retrograde pyelogram; any other cause of graft dysfunction was excluded. Controls were defined as kidney transplant recipients from the same population and period without US, matched in a 1:2 fashion by age, sex, and donor type.

RESULTS

From 532 kidney transplant patients, 31 cases and 62 controls were included. Cumulative US incidence was 58 per 1000 cases. When calculating for odds ratio (OR), post-operative urinoma (OR 3.2; 95% confidence interval [CI] 2.36-4.37) and ureteral duplication (OR 3.29; 95% CI 2.40-4.51) were associated with an increased risk for US, while DGF was not found to be statistically significant as a risk factor (OR 3.3; 95% CI 0.96-11.52). No statistically significant differences were found between groups in other pre- and post-transplant-related factors CONCLUSIONS:: DGF was not associated with US in our cohort; however, ureteral duplication and postoperative urinoma were associated with an increased risk of graft ureteral stenosis development.

Association of Double-J Stenting in Renal Transplant Patients With Urinary Tract Colonization and Infections in a Multidrug-resistant Microbe Endemic Nosocomial Environment

PURPOSE

We investigated the association of ureteral stenting after kidney transplantation with the development of urinary tract infections (UTIs) and/or urinary tract colonization, in a hospital environment considered endemic for multidrug resistant (MDR) Gram-negative Enterobacteriaceae.

METHODS

Seventy-five recipients of deceased donor grafts were divided in groups A and B. Group A (with subgroups A1 and A2) included 45 transplanted patients without urinary stenting, and group B 30 patients with stenting. Subgroup A1 consisted of 30 patients transplanted before 2006, and A2 of 15 patients transplanted after 2006, when MDR, mainly carbapenem-resistant, Enterobacteriaceae, frequency has risen in our hospital.

RESULTS

The incidence and the number of UTIs per patient were significantly higher in patients without stenting compared to those with stenting. (Group A: 32/45 vs group B: 9/30, P < .001, and group A: 2.86 ± 0.43 vs group B: 0.6 ± 0.19, P < .01 respectively). Patients without stenting tended to have a higher frequency of recurrent UTIs compared to those with stenting (group A: 16/45 vs group B: 4/30, P < .05). Asymptomatic bacteriuria was more frequent in the patients with stent (group A: 8/45 vs group B: 14/30, P < .05). Further sub-comparison of the A1 and A2 subgroups with group B did not change the statistical results.

CONCLUSIONS

There is no clinically significant association of ureteral stenting after kidney transplantation with the high frequency of MDR Gram-negative bacteria in our hospital.