[Surgical aspects of kidney transplantation in children (study of 148 cases)]

Analysis of Factors Related to the Success of Pediatric Kidney Transplantation: A 35 Years Experience

BACKGROUND

Despite the significant improvement results over the past 20 years, pediatric kidney transplantation remains a challenge. Chronic rejection, thrombosis, and recurrence of the primary disease are frequent causes of graft loss that have been little studied. Therefore, our objective is to analyze factors related to a better prognosis, which can be used to improve future strategies to allow higher pediatric transplant success rates.

METHODS

A retrospective cohort study with patients under 15 years old submitted for kidney transplantation at the Hospital das Clínicas da UNICAMP between January 1, 1987, and January 1, 2022. Age, patient weight, time and type of dialysis, use of anticoagulation, complications, ischemia time, and donor weight were analyzed and related to graft loss. The significance level adopted for the statistical tests was 5%.

RESULTS

One hundred ninety-two medical records were anaThe mean follow-up time was 11 years, and the mean graft duration was ration 8.5 years. The main causes of graft loss were chronic dysfunction, thrombosis, and acute cellular rejection. Thrombosis presented significantly with the donor's body mass index and second transplantation. There was no correlation between the analyzed variables and chronic dysfunction or acute cellular rejection.

DISCUSSION

Thrombosis remains the main cause of early graft loss, followed by acute cellular rejection. Measures such as thrombophilia screening and thromboprophylaxis have been proposed to improve results. However, they are still not standardized.

CONCLUSION

The main causes of graft loss were chronic dysfunction, thrombosis, and acute cellular rejection. Only the thrombosis was related to the donor's body mass index and a second transplantation.

Surgical complications and graft function following live-donor extraperitoneal renal transplantation in children 20 kg or less

OBJECTIVES

To evaluate the effect of patient, surgical, and medical factors on surgical complications and graft function following renal transplantation (Tx) in children weighing ≤ 20 kg, because the number of this challenging group of children is increasing.

PATIENTS AND METHODS

Between June 2009 and October 2013, 26 patients received living donor renal allotransplant using the extraperitoneal approach (EPA). The immunosuppression regimen was composed of prednisolone, mycophenolate mofetil, and ciclosporin or tacrolimus.

RESULTS

The mean weight was 16.46 ± 2.61 kg. Mean cold ischemia time was 53.85 ± 12.35 min. The graft survival rate (GSR) and patient survival rate (PSR) were 96% at 3 years. Acute rejection episodes (AREs) occurred in eight patients (30%). Postoperative surgical complications were ureteral leakage (3), vesicoureteric reflux (2), and renal vein thrombosis (2) (with one graft nephrectomy). Mean follow-up was 37.5 ± 7.4 months.

CONCLUSION

Excellent PSR and GSR can be achieved in low weight (<20 kg) recipients. Even in very low weight patients, the EPA was used. No cases were reported with primary graft non-function due to use of living donors, increasing pre-Tx body weight to at least 10 kg and maintaining adequate filling pressure before graft reperfusion. The presence of related donors and use of induction therapy and tacrolimus decreased the rate of ARE while the presence of pre-Tx lower urinary tract surgical interventions increased the rate of ureteric complications, but this was statistically insignificant.

Kidney transplantation in children weighing less than 15 kg: extraperitoneal surgical access-experience with 62 cases

Small children are a challenging group in whom to perform KT. This retrospective study analyzed the results of 62 KTs in children weighing <15 kg, performed between 1998 and 2010, using extraperitoneal access and anastomosis of the renal vessels of donors to the aorta and IVC or iliac vessels of the recipients. Thirty-two (51.6%) grafts were LRDTs and 30 (48.4%) were DDRTs-28 of them pediatric. The mean age at KT was 3.7 ± 2.2 yr (1-12), and the mean weight was 12.3 ± 2.1 kg (5.6-14.9). Ten children weighed <10 kg, and five (8.1%) children presented previous thrombosis of the venous system. At one and five yr, patient survival was 93.2% and 84.2%, and graft survival was 85.2% and 72.7%. There were no differences between the rates for LRDT and DDRT. There were six vascular complications (four vascular thromboses, one laceration, and one renal artery stenosis) and two perirenal collections. Extraperitoneal access is a valid KT technique in children weighing <15 kg.

Hydronephrosis in pediatric kidney transplant: clinical relevance to graft outcome

OBJECTIVE

To evaluate our pediatric renal transplant patient population at the Children's Hospital of Pittsburgh to better understand the clinical significance of hydronephrosis.

MATERIALS AND METHODS

We retrospectively reviewed records of patients who had received a renal transplant in 1998-2008. Exclusion criteria included multi-organ transplants and allograft failure within 3-months. We determined the incidence of hydronephrosis and compared serum creatinine, incidence of pyelonephritis, rejection and vesicoureteral reflux between the hydronephrotic and non-hydronephrotic cohorts. Data were analyzed using descriptive statistics, Student's t-test and Pearson Chi-Square test.

RESULTS

51 patients (35 male, 68.6%) were identified. The mean age at time of transplant was 8.7 ± 5.9 years and the mean follow-up period was 45.2 ± 45.4 months. Common causes of renal failure included posterior urethral valves, renal dysplasia, reflux and prune belly syndrome. Twenty-five (49%) patients developed hydronephrosis. This was associated with worsening renal function (p = 0.008). Hydronephrosis was also associated with pyelonephritis (p = 0.03) and male gender (p = 0.004). Age at transplant may be a predictor of pyelonephritis: median age of 10 patients with pyelonephritis was 4.6 years (range 0.6-19.9 years). Hydronephrotic cohort had increased rate of reflux and rejection; as not all patients underwent voiding cystourethrogram and/or allograft biopsy, this result was not significant.

CONCLUSIONS

Pediatric renal graft hydronephrosis was correlated with worsening renal function and increased incidence of pyelonephritis. More aggressive preoperative and postoperative urological testing and management should help preserve renal function.

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.

Outcome after renal transplantation in children: results of follow-up by nephrologists in a primary referral center

Pediatric patients who receive a kidney transplant require extended follow-up to monitor graft function and for management of complications. Because of convenience, most patients are sent back to the nephrologists who referred them for transplantation (the primary nephrologist) for long-term care. As a consequence, many pediatric nephrologists who provide this extended care are not associated with a transplant center. It is not known if this arrangement yields satisfactory outcomes for children and adolescents who receive a kidney transplant. The objective was to determine if clinical outcomes are satisfactory in pediatric renal transplant recipients who were followed up by their primary nephrologists after the procedure. A chart review was carried out on all renal transplant recipients seen in the renal clinic at Schneider Children's Hospital (SCH) from 1982 to 2001. Patients were eligible if they were followed up by the primary referring nephrologists at SCH for a minimum of 6 months after transplantation. Relevant demographic and clinical outcome data were compiled. Twenty-eight patients who received a total of 33 renal allografts [living related donors (LRD) 15 and cadaveric donors (CD) 18] were seen during the study period. The transplantations in 19 children (68%) were carried out at Montefiore Hospital (Bronx, NY, USA), while the rest were performed at other centers. There were three (11%) deaths, two LRD patients and one CD patient. The group of 25 surviving patients consisted of 17 males and eight females, age range 4-28 yr (mean 17.2 yr). The mean duration of renal allograft survival was 6.3 +/- 5.3 yr and the mean duration of follow-up was 6.1 +/- 5.3 yr. The most recent serum creatinine ranged from 0.5 to 3.8 mg/dL with a mean of 1.3 +/- 0.8 mg/dL. There were several complications including acute rejection, renal artery stenosis, and hydronephrosis in the allograft. The team of primary referring nephrologists successfully treated all of these except the child with hydronephrosis. The primary nephrologist who refers pediatric patients to a tertiary care transplant center can accomplish long-term follow-up of renal transplant recipients after discharge from the transplant center. The clinical outcomes are acceptable and compare favorably with the results described in the literature that have been achieved in patients followed up at transplant centers. Problems rarely developed that required referral back to the transplant center for management. This approach to care is recommended because it is more likely to foster compliance by both patients and parents.