Evaluation of factors contributing to mortality in pediatric renal transplant recipients

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.

Uncovering a Long-term Graft Survival Advantage Afforded by Infant Renal Transplants-An Organ Procurement and Transplantation Network Database Analysis

Background.

Renal transplants (Tx) are performed infrequently in infants, due to concerns related to poor outcomes. The aim of our study was to compare graft failure rates in infant (<1 y) renal Tx recipients compared with older children.

Methods.

Retrospective cohort study of pediatric renal Tx recipients from 2000 to 2015, using the Organ Procurement and Transplant Network database. A log-linear event history regression model for time to graft failure, adjusting for age group and important confounders, was used to estimate post-Tx graft failure probabilities.

Results.

In 2696 Tx followed for a median of 6.1 y, 704 failures were observed. Significant predictors of graft failure were year of Tx (for each year after 2000, rates were 8.6% lower), Black race-ethnicity (63% higher compared with Whites), and number of HLA matches. For infants (n = 27), estimated graft failure percentage (95% confidence interval) within the first 1-, 2-, and 5-y post-Tx were 10.4 (0.1–21.1), 11.9 (1.2–22.6), and 16.4 (4.9–27.9). For the 1- to 11-y-olds (n = 1429), these were 3.8 (3.0–4.6), 6.3 (5.4–7.3), and 13.6 (12.2–15.0), respectively, and for the 12+ y olds (n = 1240), they were 3.8 (3.1–4.5), 8.1 (7.2–9.0), and 19.9 (18.1–21.7), respectively (P < 0.001 for 5-y graft failure rate across age groups).

Conclusions.

Infant renal Tx recipients experience a higher graft failure rate in the first year, compared with older cohorts, but over longer intervals, cumulative failure rates are comparable or even lower. To minimize early graft losses such Tx should be performed in experienced centers.

Kidney transplantation in children weighing 15 kg or less is challenging but associated with good outcome

OBJECTIVE

Pediatric kidney transplantation (KT) in small children is assumed to be related to potential surgical complications that may cause severe morbidity and graft loss. The aim of our study was to analyze the outcome of KT recipients weighing ≤15 kg, focusing on surgical complications, associated morbidity and mortality, as well as allograft loss.

METHODS

We reviewed our retrospective institutional database for recipients of KT between January 2000 and December 2014 with body weight ≤15 kg.

RESULTS

Forty-four children weighing ≤15 kg, out of a total of 164 children (26.8%), received a deceased donor KT at our center during the study period. Mean weight was 10.10 ± 2.9 kg (3-15 kg), and weight was ≤10 kg in 23 patients (52.3%). The allograft was implanted intraperitoneally in two cases (4.5%) and extraperitoneally in the remaining 42 (95.5%). Two patients received a simultaneous double liver-kidney transplant. Postoperative complications appeared in 10 patients (22.7%) and eight required reintervention. Five allografts (11.4%) were lost secondary to surgical complications. No statistically significant differences in surgical complications were observed when compared with patients weighing >15 kg. Actuarial graft survival was 81% and 73% at 1 and 5 years, respectively. No significant differences in graft survival were observed compared with patients >15 kg. Mean follow-up was 84.95 ± 50 months (1-190 months).

CONCLUSIONS

Our results demonstrate that KT in children weighing ≤15 kg is challenging but not associated with increased risk of surgical complications or early graft loss.

Vascular anastomosis for paediatric renal transplantation and new strategy in low-weight children

The technical aspects of RT in low-weight children should be specific, particularly with regard to VA. This retrospective study assesses the main VA options in paediatric RTs and proposes a new strategy for renal artery trajectory when using the Ao and the right iVC. The sample included 81 patients and was categorized into a group of children weighing <16 kg and the other group of children weighing 16 kg or more. The smaller children received the graft predominantly on the Ao and iVC (63%); however, the VA options varied in children weighing more than 16 kg, with anastomoses predominantly to the common iliac vessels (46%). In the first group, when the Ao was the selected vessel for anastomosis on the right side, the trajectory adopted for the transplanted kidney artery was posterior to the iVC. This strategy may reduce the risk of compression of the iVC by the renal artery of the donor kidney and may reconstitute the normal anatomy of the renal artery. Moreover, it did not represent a risk factor for graft loss in this sample.

Vascular and haemorrhagic complications of adult and paediatric live-donor renal transplantation: A single-centre study with a long-term follow-up

Objectives

To compare the haemorrhagic and vascular complications between paediatric and adult renal transplant recipients with a long-term follow-up.

Patients and methods

Between March 1976 and December 2006, in all, 1865 live-donor renal transplants were carried out. Patients were stratified according to their ages into two groups; paediatric (⩽18 years; 259) and adult (>18 years; 1606). Variables assessed included incidence, risk factors, management and sequelae of vascular and haemorrhagic complications. The effect of these complications on patient and graft survival was compared.

Results

Haemorrhage requiring active intervention (percutaneous drainage or surgical exploration) was reported in seven children (2.7%) and 29 adults (1.8%), while thrombotic or stenotic complications were recorded in two children (0.77%) and 19 adults (1.18%; P < 0.05). Female gender, delayed onset of diuresis and acute tubular necrosis were significant predictors of vascular complications on univariate analysis, but none remained significant on multivariate analysis. In adults, vascular complications had a significant negative effect on mean (SD) 10-year graft survival compared to patients with no complications, at 19.8 (7.63)% vs. 55.7 (1.66)% (P = 0.01). Children who developed vascular complications had a significantly higher 5- and 10-year graft survival rate than adults (P = 0.01).

Conclusion

The incidence of vascular complications is comparable in paediatric and adult transplants. Vascular complications had a significant negative influence on graft survival in adult recipients. Children who developed vascular complications appear to tolerate its effects and have a better graft survival than have adults.

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.

Hypercoagulable states in renal transplant candidates: impact of anticoagulation upon incidence of renal allograft thrombosis

INTRODUCTION

Although multiple studies of demographic variables have been associated with allograft thrombosis, these results are not routinely reproducible. Are ESRD patients with hypercoagulable states (HCS) (antithrombin III deficiency, protein S or C deficiency, activated protein C resistance, and anticardiolipin antibodies) at predictably greater risk for allograft thrombosis?

METHODS

Between 1996 and 1999, all renal transplant candidates were screened for hypercoagulability risk factors [HRF] (multiple arteriovenous access thromboses, prior deep vein thrombosis, prior allograft thrombosis, collagen vascular disease, multiple miscarriages, diabetes, autoimmune disease, and Fabry's disease). HRF(+) candidates were then tested for HCS status. We administered preemptive posttransplant i.v. Heparin in HCS(+) patients and observed the impact of this intervention upon the incidence of allograft thrombosis. We compared demographic data and incidence of allograft thrombosis in an historic control (346 patients transplanted between June 31, 1992, and March 5, 1996) not tested for HCS and a study cohort (502 patients transplanted between March 6, 1996, and June 31, 1999) prospectively screened for HRF. HRF(+) patients who were HCS(+) in the study cohort received i.v. heparin immediately after transplant and p.o. warfarin as outpatients.

RESULTS

Demographic characteristics previously implicated in allograft thrombosis were equivalently distributed in both cohorts with the exceptions that more living-donor transplants (33.1% vs. 15.3%) were performed in study cohort, CIT>24 hr occurred in more control patients (37.3% vs. 22.1%) and more study patients (16.7% vs. 0%) received tacrolimus. Hypercoagulable states were found upon reevaluating five of seven controls (71.4%), who lost prior allografts to thrombosis. Hypercoagulable states were prospectively detected in 10 study patients with hypercoagulability risk factors. Most (9 of 10) study patients receiving anticoagulation have achieved long-term allograft function. Study group allograft thrombosis incidence was reduced (1.59% vs. 4.05%). Hypercoagulable states were demonstrated in most episodes of allograft thrombosis. Control patients who lost prior allografts to thrombosis were anticoagulated after retransplantation and 100% achieved long-term allograft function.

CONCLUSIONS

Long-term allograft function has been achieved in 90% of study patients when prophylactically anticoagulating study patients with hypercoagulable states. A 2.6-fold reduction in the expected incidence of allograft thrombosis was observed in anticoagulated patients with hypercoagulable states.

Studies of avoidable factors influencing death: a call for explicit criteria

OBJECTIVE

To analyse studies evaluating cases of potentially "avoidable" death.

DESIGN

The definitions, sources of information, and methods were reviewed with a structured protocol. The different types of avoidable factors,--that is, deficiencies in medical care that may have contributed to death--were categorised. The presence of explicit classifications and standards was examined. basic criteria for quality of the studies were defined and the numbers of studies fulfilling these criteria were assessed.

SETTING AND PARTICIPANTS

65 studies, published during 1988-93 in peer reviewed medical journal for which the title, or abstract, or both indicated that they had analysed potentially avoidable factors influencing death. Studies analysing aggregated data only, were not included.

RESULTS

Only one third of the studies fulfilled basic quality criteria,--namely, that the avoidable factors examined should be defined and the sources of information and people responsible for the judgements presented. The definitions used comprised two levels, one stating that there had been errors in management (process) and the other that the errors may have contributed to the deaths (outcome). Only 15% of the studies explicitly defined what type of factors they had looked for and 8% referred to specified standards of care.

CONCLUSIONS

Studies of avoidable factors influencing death may have considerable potential as part of a system of improving medical care and reducing avoidable mortality. At present, however, the results from different studies are not comparable, due to differences in materials and methods. There is a need to improve the quality of the studies and to define standardised explicit definitions and classifications.

Mortality trends in pediatric patients with chronic renal failure

Mortality trends were analyzed in 441 children and adolescents with chronic renal failure (CRF) observed over a 24-year period before and after institution of renal replacement therapy (RRT). A total of 93 patients died. Overall mortality rate (MR) per 100 patient years decreased from 6.6 in 1969-1978 to 2.5 in 1979-1988 and increased slightly to 2.9 in 1989-1992. The fall involved all four modes of treatment: conservative, hemodialysis (HD), continuous peritoneal dialysis (CPD), and transplantation (TX). From 1979-1988 to 1989-1992 MR on conservative and on dialysis treatment changed only slightly and was similar on HD and CPD. An alarming rise in MR was noted after TX in 1989-1992, mainly due to malignant tumors. In 44 patients who died on conservative treatment, the reasons for non-acceptance for RRT were analyzed: in 22 multi-morbidity was the main reason, usually because of a congenital neurological disorder. Some patients died from advanced uremia or unexpected events after the decision to institute RRT. Our experience demonstrates a persistent mortality in pediatric patients with CRF, which in recent years is primarily ascribed to congenital multi-morbid conditions which make RRT unfeasible, infections on dialysis treatment, and malignancies after TX.

Hemostatic complications in renal disorders of the young

This review focuses on the hemorrhagic and thrombotic complications sometimes associated with the most common renal disorders in children. A Medline search of the literature was conducted from 1966 to January 1995, using combinations of key words appropriate for each disorder. Additional references were located through the bibliographies of the publications and recent journals were searched independently. The most common renal disorders with hemostatic complications in children were: renal vein thrombosis (268 children in 80 publications), hemolytic uremic syndrome (473 children in 29 publications), nephrotic syndrome (4,158 children in 51 publications), renal transplantation (3,976 children in 14 publications), glomerulonephritis (20 publications), end-stage renal disease, and dialysis (22 publications). The age distribution, clinical presentation, etiology, diagnosis, treatment, and outcome of the affected children were analyzed for each disorder. Children with inherited pre-thrombotic disorders usually do not present during childhood unless there is a secondary risk factor. Similarly, most children with renal disease do not develop thromboembolic complications. Therefore, when a child with a renal disorder develops a thromboembolic event, evaluation for an inherited pre-thrombotic disorder should be seriously considered. Guidelines for the use of heparin and warfarin in these children (both therapeutically and prophylactically) are given. At this time, the risk/benefit of thrombolytic therapy in children is not known and a general recommendation for thrombolytic therapy cannot be made.

Diagnosis and treatment of cytomegalovirus disease in pediatric renal transplant recipients

The purpose of this study was to identify factors associated with the development of cytomegalovirus (CMV) disease and to assess the morbidity of this illness in pediatric renal transplant patients. The authors retrospectively reviewed the records of 135 patients (< 18 years of age) who underwent a total of 151 transplants (146 kidney transplants, five kidney/liver transplants) over 5 years (average follow-up period, 33.0 +/- 21.7 months). They assessed the risk factors that previously have been associated with the development of CMV disease in adults (age, occurrence of acute rejection episodes, and preoperative donor and recipient CMV serological status) and evaluated the incidence of associated graft loss and mortality. Twenty-two episodes of CMV disease were diagnosed based on evidence of CMV infection and on clinical symptoms; the episodes were treated in 17 patients. A multivariate analysis showed that the development of CMV disease was associated with age of > or = 13 years (P = .02), concomitant liver transplantation (P = .01), and treatment of acute rejection (P = .04). In addition, patients who were CMV-seronegative preoperatively and received a graft from a CMV-seropositive donor (P = .04) or who were CMV-seropositive preoperatively and received a graft from a CMV-seronegative donor (P = .02) were more likely to have CMV disease. Although all patients with CMV disease required hospitalization and were treated with intravenous ganciclovir, CMV disease was not associated with increased allograft loss or mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Causes of kidney allograft loss in a large pediatric population at a single center

At our institution, 521 kidney transplants were performed in 429 children (mean age 8.7 +/- 5.6-years) between 1969 and 1991. Of these transplants, 408 were primary, 113 were retransplants, 347 were living related, 171 were cadaver, and 3 were living nonrelated. Immunosuppression consisted of prednisone, azathioprine, and Minnesota antilymphocyte globulin (non-CSA) in 339 patients, total lymphoid irradiation in 8, and, more recently, cyclosporine (CSA) in addition in 168 patients. Average follow-up was 8.8 +/- 6.0 years. Actuarial graft survival in the non-CSA versus CSA groups at 1 year was 77.0% versus 85.7%; at 5 years, 59.6% versus 71.9%. Of 136 non-CSA patients, causes of graft loss at 5 years included: chronic rejection in 55 (40.4%), acute rejection in 27 (19.9%), recurrent disease in 16 (11.8%), technical complications in 8 (5.9%), infectious complications in 4 (2.9%), other causes in 5 (3.7%), and death with a functioning graft in 21 (15.4%). Of 40 CSA patients, causes of graft loss at 5 years included: chronic rejection in 16 (40.0%), acute rejection in 8 (20.0%), recurrent disease in 6 (15.0%), technical complications in 3 (7.5%), other causes in 2 (5.0%), and death with a functioning graft in 5 (12.5%). The causes of graft loss did not significantly differ in the non-CSA and CSA groups. Chronic rejection was the most common cause of graft loss in both groups. Research focusing on chronic rejection is needed to improve graft outcome in pediatric kidney transplantation.