Effect of donor/recipient body weight ratio, donor weight, recipient weight and donor age on kidney graft function in children

Complex Bench Surgery Does Not Increase the Risk of Vascular Complications after Pediatric Kidney Transplantation

INTRODUCTION

 Vascular complications are severe complications of pediatric kidney transplantation (KT). We aimed to investigate whether a complex bench surgery (BS) affects the outcomes.

METHODS

 All pediatric KT performed at the University Hospital of Padua from 2015 to 2019 were analyzed, comparing those in which a standard BS was possible to those that necessitated a complex BS. The rates of vascular complications, patients' outcome, and graft survival were compared in the two groups.

RESULTS

 Eighty KTs were performed in 78 patients with a median age of 11 years (interquartile range [IQR] 4.3-14) and a median body weight of 24 kg (IQR 13-37). Thirty-nine donor kidneys (49%) needed a complex BS due to anomalies of renal veins in 12 (31%) and renal arteries in 16 (41%). The remaining 11 grafts (28%) underwent an elongation of the vein. There was no difference in the rate of primary graft non function (p = 0.97), delayed graft function (p = 0.72), and overall survival (p = 0.27). The rates of vascular complications, bleedings, and venous graft thrombosis were similar (p = 0.51, p = 0.59, p = 0.78, respectively). No arterial thrombosis or stenosis was reported.

CONCLUSION

 Complex BS did not compromise survival of the graft and did not put the allograft at risk of vascular complications, such as bleedings or thrombosis.

The Predictive Value of Donor Renal Functions, Graft Weight, Recipient Body Mass Index, and Human Leucocyte Antigen Match Regarding Early Graft Functions

Background and objective Graft performance is the most important postoperative parameter for patients undergoing kidney transplantation (KTx). The renal function of the donor is reported to be correlated with graft function after KTx. The body mass index (BMI) is also one of the important parameters involved in the prediction of graft function. The aim of this retrospective study was to examine the relationship between early postoperative graft function in patients undergoing KTx and donor cystatin C and estimated glomerular filtration rate (e-GFR) levels, graft weight/recipient BMI (G/B) ratio, and human leukocyte antigen (HLA) tissue compatibility. Materials and methods A total of 215 cases (215 donors, 215 recipients) who underwent KTx at our center between January 2018 and December 2022 were included in the study. Patients' age, sex, BMI, preoperative donor serum cystatin C and e-GFR levels, HLA tissue compatibility, graft weights, and recipient creatinine levels were recorded one week postoperatively. The Kolmogorov-Smirnov test and histogram plots were used to analyze the conformity of the variables to the normal distribution and Spearman's correlation test was used to analyze the relationship between variables. Results A negative correlation was identified between recipient creatinine level and G/B ratio and donor e-GFR (r = -0.256 and -0.137, respectively). Donor cystatin C level showed a positive correlation with recipient creatinine level (r = 0.242). No significant correlation was noted in terms of tissue matching rates (p = 0.616). Conclusion Although these three parameters are correlated with early graft functions, the graft weight/recipient BMI ratio has the strongest correlation.

Extraperitoneal kidney transplantation: a comparison between children weighting ≤15 kg and >15 kg. Experience of a single institution

Extraperitoneal approach is sometimes recommended for kidney transplantation (KT) in children weighting <15 kg. We hypothesized that this approach might be as successful as in patients with normal weight. Data of all consecutive KTs performed between 2013 and 2019 were retrospectively reviewed. Early outcomes and surgical complications were compared between children weighing ≤15 kg (low‐weight (LW) group) and those weighing >15 kg (Normal‐weight (NW) group). All the 108 KTs were performed through an extraperitoneal approach. The LW group included 31 patients (mean age 3.5 ± 1.4 years), whose mean weight was 11.1 ± 2.0 kg. In the LW group,—a primary graft nonfunction (PNGF) occurred in one patient (3.2%), surgical complications occurred in nine (29%), with four venous thrombosis. In the NW group, PNGF occurred in one case (1.3%), delayed graft function (DGF) in eight (10%), surgical complications in 11 (14%) with only one case of venous thrombosis. In both groups, no need for patch during wound closure and no wound dehiscence were reported. The extraperitoneal approach can be effectively used in LW children. No differences were observed in the overall complication rate (P = 0.10), except for the occurrence of venous thrombosis (P = 0.02). This might be related to patients’ characteristics of the LW group.

Clinical implication of renal allograft volume to recipient body surface area ratio in pediatric renal transplant

Our study aims to assess the clinical implication of RAV/rBSA ratio in PRT as a predictor for attained renal function at 1 year post-transplantation and its association with surgical complications. A retrospective cohort was performed for PRT cases from January 2000 to December 2015 in our institution. Extracted clinical information includes the recipient's demographics, donor type, renal allograft characteristics, arterial, venous and ureteral anastomoses, vascular anastomosis time while kidney off ice, overall operative time, and estimated blood loss. The RAV/rBSA was extrapolated and assessed for its association with renal graft function attained in 1 year post-transplantation and surgical complications within 30-day post-transplantation. A total of 324 PRTs cases were analyzed. The cohort consisted of 187 (52.4%) male and 137 (42.3%) female recipients, with 152 (46.9%) living donor and 172 (53.1%) deceased donor renal transplants, and an overall median age of 155.26 months (IQR 76.70-186.98) at time of renal transplantation. The receiver operating characteristic identified that a RAV/rBSA ratio of 135 was the optimal cutoff in determining the renal graft function outcome. Univariate and multivariate analyses revealed the relative OR for RAV/rBSA ≥ 135 ratio in predicting an eGFR ≥ 90 attained within 1 year post-transplant was highest among younger pediatric recipients (<142.5 months) of deceased kidney donors (OR = 11.143, 95% CI = 3.156-39.34). Conversely, Kaplan-Meier analysis revealed that RAV/rBSA ratio ≥ 135 is associated with lower odds of having eGFR <60 (OR = 0.417, 95% CI = 0.203-0.856). The RAV/rBSA ratio was not associated nor predictive of transplant-related surgical complications. Our study determined that the RAV/rBSA ratio is predictive of renal graft function at 1-year PRT, but not associated with any increased surgical complications.

Living donor risk model for predicting kidney allograft and patient survival in an emerging economy

AIM

Living donor kidney is the main source of donor organs in low to middle income countries. We aimed to develop a living donor risk model that predicts graft and patient survival in an emerging economy.

METHODS

We used data from the Sindh Institute of Urology and Transplantation (SIUT) database (n = 2283 recipients and n = 2283 living kidney donors, transplanted between 1993 and 2009) and conducted Cox proportional hazard analyses to develop a composite score that predicts graft and patient survivals.

RESULTS

Donor factors age, creatinine clearance, nephron dose (estimated by donor/recipient body weight ratio) and human leukocyte antigen (HLA) match were included in the living donor risk model. The adjusted hazard ratios (HRs) for graft failures among those who received a kidney with living donor scores (reference to donor score of zero) of 1, 2, 3 and 4 were 1.14 (95%CI: 0.94-1.39), 1.24 (95%CI:1.03-1.49), 1.25 (95%CI:1.03-1.51) and 1.36 (95%CI:1.08-1.72) (P-value for trend =0.05). Similar findings were observed for patient survival.

CONCLUSIONS

Similar to findings in high income countries, our study suggests that donor characteristics such as age, nephron dose, creatinine clearance and HLA match are important factors that determine the long-term patient and graft survival in low income countries. However, other crucial but undefined factors may play a role in determining the overall risk of graft failure and mortality in living kidney donor transplant recipients.

Outcome of renal transplantation in small infants: a match-controlled analysis

BACKGROUND

Infants with a body weight of less than 10 kg are often not considered to be suitable candidates for renal transplantation (RTx). The objective of this study was to evaluate this arbitrary weight threshold for pediatric RTx.

METHODS

We conducted a multicenter, retrospective, match-controlled cohort study on infants weighing less than 10 kg at time of engrafting (low-weight group [LWG], n = 38) compared to a matched control group (n = 76) with a body weight of 10-15 kg, using data from the first 2 years post-transplant derived from the CERTAIN Registry.

RESULTS

Patient survival was 97 and 100% in the LWG and control groups, respectively (P = 0.33), and death-censored graft survival was 100 and 95% in the LWG and control groups, respectively (P = 0.30). Estimated glomerular filtration rate at 2 years post-transplant was excellent and comparable between the groups (LWG 77.6 ± 34.9 mL/min/1.73 m²; control 74.8 ± 29.1 mL/min/1.73 m²; P = 0.68). The overall incidences of surgery-related complications (LWG 11%, control 23%; P = 0.12) and medical outcome measures (LWG 23%, control 36%, P = 0.17) were not significantly different between the groups. The medical outcome measures included transplant-related viral diseases (LWG 10%, control 21%; P = 0.20), acute rejection episodes (LWG 14%, control 29%; P = 0.092), malignancies (LWG 3%, control 0%; P = 0.33) and arterial hypertension (LWG 73%, control 67%; P = 0.57).

CONCLUSIONS

These data suggest that RTx in low-weight children is a feasible option, at least in selected centers with appropriate surgical and medical expertise.

Clinical and pathological features of donor/recipient body weight mismatch after kidney transplantation

BACKGROUND

Previous studies have shown that a donor/recipient body weight mismatch affects long-term graft survival and graft function after kidney transplantation. However, the mechanisms are not fully understood.

AIM

To address the mechanisms, we compared the pathological and physiological features between patients with a donor/recipient body weight mismatch and those without a mismatch 1 yr after kidney transplantation. Furthermore, we investigated the correlation with the donor/recipient body weight ratio.

METHODS

We examined allograft biopsy specimens from 10 recipients with stable kidney function, with body weight mismatch (donor/recipient body weight ratio [D/R BWR] < 0.9), and compared them with samples from 13 patients without mismatch. We measured glomerular volume (GV) using the Weibel-Gomez method and glomerular density (GD) defined by nonsclerotic glomerular number/renal cortical area as pathological findings. The physiological parameters included estimated glomerular filtration rate and proteinuria (mg/day). These data were evaluated to identify a correlation with D/R BWR.

RESULTS

The pathological features showed that GV and GD were identical in the two groups. However, when glomerular enlargement was defined by ΔGV (GV at the 1-yr biopsy minus GV at baseline biopsy), ΔGV was higher in mismatch cases compared with that in cases without a mismatch (10.6 ± 4.6 vs. 5.5 ± 7.1 × 10(5) μm(3) ; P = 0.049). Furthermore, D/R BWR was significantly correlated with ΔGV (P = 0.03, r = -0.436). eGFR values were physiologically identical between the two groups, but the mismatch cases had significantly higher proteinuria levels than that of the cases without a mismatch at 1 yr after kidney transplantation.

CONCLUSION

A donor/recipient body weight mismatch could affect glomerular enlargement and increased proteinuria 1 yr after kidney transplantation. How these two features affect long-term graft survival and function must be addressed in the future.

A study to evaluate the effect of ratio of donor kidney weight to recipient body weight on renal graft function

AIM AND OBJECTIVES

To study the effect of the ratio of donor kidney weight (dkw) to recipient body weight (rbw) on short and long term graft function in live donor kidney transplant patients.

MATERIALS AND METHODS

It was a prospective study of 79 live donor kidney transplant recipients. Patients were divided into three groups depending on the ratio of dkw in grams to rbw in kilograms. Serum creatinine in milligrams percent on the day of surgery, 7(th) day, 1 month, 6 months, 1 year, and 3 years after the surgery was recorded and their means compared.

RESULTS

The comparison showed that the decrease in mean creatinine level was more in group three patients as compared with group 2 and one patients at 7 days (1.04,1.44 and 1.59 in group 3,2 and 1 respectively) and 30 days (1.12,1.36 and 1.45 in group 3,2 and 1 respectively), showing that higher dkw/rbw ratio is beneficial with respect to the early graft function. However this decrease was not statistically significant (P value -0.256 and 0.358 respectively on 7(th) and 30(th) day). Furthermore long-term function was not different among these three groups.

CONCLUSION

The ratio of dkw to rbw does not have a significant effect on long-term graft function inspite of an early improvement in the function with increased dkw to rbw ratio.