Anticoagulation post-renal transplant: is it indicated?

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.

Thromboprophylaxis after kidney transplantation in children: Ten-year experience of a single Brazilian center

BACKGROUND

Kidney transplantation is the gold standard treatment for children with end-stage chronic kidney disease. Graft thrombosis is an important cause of graft failure, with high morbidity, mortality, and impact on quality of life and to the health system. The role of thromboprophylaxis in this setting is still uncertain. We describe the demographic characteristics and thrombotic risk factors in pediatric renal transplant recipients, determining the rate of renal graft thrombosis, and discuss the role of thromboprophylaxis.

METHODS

This retrospective study reviewed 96 pediatric renal transplantations between 2008 and 2017 in a single hospital. Patients were assigned to one of two groups: children who did not receive thromboprophylaxis after transplantation and those who did. We reported their characteristics, comparing the incidence of graft thrombosis and hemorrhagic complications between the groups.

RESULTS

Forty-nine patients (51%) received thromboprophylaxis. Thrombosis occurred in 5 patients who did not receive thromboprophylaxis (5.2%) compared with none in the group that did (p = .025). In all patients, renal graft thrombosis resulted in early graft loss. Thirteen patients had hemorrhagic complications. Seven were unrelated to pharmacological thromboprophylaxis (2 major, 1 moderate, and 4 minor bleeding, which either did not receive thromboprophylaxis or had bleeding prior to thromboprophylaxis), while six occurred during heparinization (2 major, 1 moderate, and 3 minor bleeding). There was no significant difference in the rate of hemorrhagic complications between the groups (p = .105).

CONCLUSIONS

The rate of renal graft thrombosis was 5.2%. Thrombosis remains an important cause of early graft loss. Thromboprophylaxis was associated with a reduction in graft thrombosis without increased risk of bleeding.

Assessment of prophylactic heparin infusion as a safe preventative measure for thrombotic complications in pediatric kidney transplant recipients weighing <20 kg

Small-sized kidney recipients (<20 kg) are at high risk of allograft vessel thrombosis. HP has been used to mitigate this risk but may infer an increase in bleeding risks. Therefore, we aim to determine whether HP is a safe means to prevent thrombosis in small kidney transplant patients by comparing those who have received HP and those who have NHP. A retrospective review of patients < 20 kg who underwent kidney transplant in our institution from 2000 to 2015 was performed. At our institution, unfractionated heparin 10 units/kg/hour is used as HP since 2009. Patients at increased risk of thrombosis (previous thrombosis, thrombophilia, nephrotic syndrome) and bleeding (therapeutic doses of heparin, diagnosis of coagulopathy) were excluded. Fifty-six patients were identified (HP n = 46; NHP n = 10). Baseline demographics were similar between HP and NHP. There was no statistical difference in frequency of transfusions, surgical re-exploration, or thrombotic events between HP and NHP. The HP group was more likely to have drop in Hb > 20 g/L (67.4% vs 30.0%, P = 0.038), and those who had drop in Hb > 20 g/L were more likely to also require pRBC transfusions (63.0% vs 20.0%, P = 0.017). Within the HP group, those who had bleeding complications had similar Hb levels as those who did not at baseline and post-transplant. Outcomes in the HP and NHP groups were no different with respect to thrombosis or significant bleeding complications requiring pRBC transfusions or surgical intervention. Future prospective studies are required to investigate the balance of preventing thrombosis and risks of pRBC transfusions for small-sized kidney recipients.

Pediatric transplantation: preventing thrombosis

Due to progressive advances in surgical techniques, immunosuppressive therapies, and supportive care, outcomes from both solid organ transplantation and hematopoietic stem cell transplantation continue to improve. Thrombosis remains a challenging management issue in this context, with implications for both graft survival and long-term quality of life. Unfortunately, there remains a general paucity of pediatric-specific data regarding thrombosis incidence, risk stratification, and the safety or efficacy of preventative strategies with which to guide treatment algorithms. This review summarizes the available evidence and rationale underlying the spectrum of current practices aimed at preventing thrombosis in the transplant recipient, with a particular focus on risk factors, pathophysiology, and described antithrombotic regimens.

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.

[Kidney transplantation in childhood: from milimeter to centimeters]

Graft survival is worse in recipient aged less than 5 years due to the greater risk of vascular thrombosis. Thrombosis may be prevented by the choice of the donor, method of surgery, perioperative hemodynamic optimisation and preventive anti-coagulation. Normal growth is a major objective of the management of transplanted children. The mean final height increased during the 20 last years to be between -1.63 and -0.92 SDS depending on age and period of the transplantation.