Pediatric Renal Transplantation: Evaluation of Long-Term Outcomes and Comparison to Adult Population

Evaluation of the learning curve of pediatric kidney transplantation anesthesia

Background/aim

Pediatric kidney transplantation (PKT) anesthesia brings some different challenges than adult kidney transplantation (KT) anesthesia and there are still no studies analyzing the role of experience on PKT outcomes. In this study, we aimed to evaluate the anesthesia learning curve in pediatric kidney transplants performed in our institution and the effect of increasing experience on renal transplantation-related data.

Materials and methods

Patients age ≤ 18 years who underwent KT were included in the study, while patients age >18 years were excluded. Patients were divided into 3 groups according to the date of transplant, as the first 10 patients in Group 1, the second 10 patients in Group 2, and the final 11 in Group 3. Groups were compared according to recorded data.

Results

Thirty-one patients were included in the study. Age, sex, and body mass index were matched between the 3 groups. The mean durations of dialysis were 75.0 ± 63.0, 22.4 ± 27.9, and 5.7 ± 4.5 months for Group 1, Group 2, and Group 3, respectively (p = 0.009). Blood loss, duration of postoperative mechanical ventilation, and length of stay in the intensive care unit (ICU) were comparable between the groups. The duration of anesthesia gradually shortened from Group 1 to Group 3 but there was no significant difference between the groups. The mean number of red blood cell (RBC) transfusion was 0.9 ± 0.7 unit in group 1. It decreased to a mean of 0.6 ± 0.7 unit for group 2, and afterward significant decrease occurred down to 0 for group 3 (p = 0.004).

Conclusion

Our results demonstrate that considering the decrease in preoperative dialysis duration and operative RBC transfusion, 20 patients may be enough for anesthesia competency. Transplantation anesthesia experience before PKT, anesthesia technique, and patient characteristics may differ between institutions. Therefore, further prospective studies with established learning curve goals, larger patient volumes, and more variables are needed to validate our results.

Surgical complications in pediatric kidney transplantation-Incidence, risk factors, and effects on graft survival: A retrospective single-center study

The field of pediatric kidney transplantation remains challenging due to an ongoing lack of size-matched grafts and anatomical peculiarities. In the current study, we investigated the incidence of surgical complications in pediatric recipients, with a focus on risk factors and effects on graft outcome. We retrospectively reviewed all 2386 kidney transplantations at our institution from January 2005 until December 2018. Of these, 221 transplants were performed in pediatric recipients, defined as under the age of 18 years. Donor-recipient body surface area ratios were calculated to evaluate the effects of size mismatching. Regression analyses were performed to identify independent risk factors for surgical complications and graft survival, respectively. Perioperative surgical complications requiring revision were observed in 34 (15.4%) cases. Leading cause for revision were vascular complications such as thrombosis or stenosis (n = 15 [6.8%]), which were significantly more frequent in case of young donors, (ie, donor age <6 years; OR: 4.281; CI-95%:1.385-13.226; P = .012), previous nephrectomy (OR: 3.407; CI-95%:1.019-11.387; P = .046), and en-bloc grafts (OR: 4.923; CI-95%:1.355-17.884; P = .015), followed by postoperative hemorrhage (n = 10 [4.5%]), ureteral complications (n = 8 [3.6%]), and lymphoceles (n = 7 [3.2%]). Median follow-up was 84.13 (0.92-175.72) months. One-, 5-, and 10-year graft survival rates were 97.1%, 88.9%, and 65.1%, respectively. Except for vascular complications (HR: 4.727; CI-95%:1.363-16.394; P = .014), none of the analyzed surgical morbidities significantly influenced graft survival. In conclusion, pediatric kidney transplantation achieves excellent long-term results. However, meticulous surgical technique and continuous postoperative monitoring are imperative for early detection and treatment of imminent vascular complications, especially in case of young donors and en-bloc grafts.

Impact of Matrix Metalloproteinases 2 and 9 and Tissue Inhibitor of Metalloproteinase 2 Gene Polymorphisms on Allograft Rejection in Pediatric Renal Transplant Recipients

OBJECTIVES

Acute and chronic allograft rejection have been continuously an important obstacle in the follow-up of renal transplant recipients. During clinical management, several factors acting simultaneously result in acute rejection and chronic allograft nephropathy. Matrix metalloproteinases and tissue inhibitors of metalloproteinases are responsible for the organization of the extracellular matrix and play roles in cell proliferation and cellular invasion. Changes in matrix metalloproteinase expression levels have been reported to be associated with renal allograft rejection and interstitial fibrosis. In this study, we aimed to investigate functional polymorphisms of MMP2, MMP9, and TIMP2 genes in pediatric renal transplant recipients.

MATERIALS AND METHODS

Our study included 68 kidney transplant recipients and 58 control patients. The kidney transplant recipient group was further divided into 2 subgroups: no graft rejection (n = 47) and graft rejection (n =21). MMP2 -735C >T (rs2285053), MMP2 -1306C >T (rs243865), MMP2 -1575G >A (rs243866), MMP9 c.-1562C >T (rs3918242), TIMP2 -418G >C (rs8179090), and TIMP2 303C > T (rs2277698) polymorphisms were analyzed with the use of polymerase chain reaction and restriction fragment-length polymorphism methods. Allele prevalence was compared with reference values of the control group, and Hardy-Weinberg equilibrium was tested.

RESULTS

Mean ages were 16.7 ± 3.9 years for the study group and 14.8 ± 5.6 years for the control group. The mean follow-up time after transplant was 37.7 ± 7.9 months. We compared allele frequencies in the 2 groups and calculated a statistically significant difference in rs2285053, rs243865, rs243866, rs3918242, rs8179090, and rs2277698 polymorphism frequencies between the transplant recipients and control patients. When the transplant recipient group was compared in itself with regard to allograft rejection, all investigated polymorphisms except TIMP2 -418G >C (rs8179090) revealed a statistically significant difference between those with and without rejection (P < .05).

CONCLUSIONS

Matrix metalloproteinases and their tissue inhibitors could be important predictive biological markers for the follow-up of kidney transplant recipients.