Benefits of Anticoagulation Prophylaxis in Children Undergoing Kidney Transplant: Systematic Review and Meta-Analysis.

Background: Graft thrombosis is a preventable cause of early allograft loss after pediatric kidney transplant, but the role of primary thromboprophylaxis is uncertain.

Objectives: To determine the effectiveness and safety of thromboprophylaxis in preventing graft thrombosis among children (0-21 years) undergoing kidney transplant.

Methods: We performed a systematic literature review of MEDLINE, Embase, and Cochrane Libraries from inception until September 2024. The primary outcome assessed by meta-analysis was graft thrombosis, and the secondary outcome was major bleeding (per International Society on Thrombosis and Haemostasis criteria).

Results: Twenty-five observational studies (21 retrospective, 4 prospective) describing 2,094 patients (1,659 cases, 435 controls) met eligibility criteria. Thromboprophylaxis was used universally (ie, all kidney recipients in the study) in 64% (1,055/1,659) or only in high-risk patients (recipient weight <20 kg, age <5 years) in 36% (604/1,659). Compared with no preventive measures for thrombosis, thromboprophylaxis was associated with reduced risk of graft thrombosis (odds ratio, 0.31; 95% CI, 0.18-0.53). Subgroup analyses of heparinoid-only, universal thromboprophylaxis, and high-risk-only protocols revealed similar findings. Thromboprophylaxis was not associated with increased risk of bleeding resulting in surgical exploration or graft loss. The overall risk of bias was moderate. Studies showed high clinical and methodologic heterogeneity in study populations and thromboprophylaxis protocols.

Conclusions: Primary thromboprophylaxis appears effective in preventing kidney graft loss from vascular thrombosis in pediatric recipients. This benefit may be offset by the risk of bleeding, although clarity on bleeding risk factors is lacking. We identified knowledge gaps, including uncertainty about optimal thromboprophylaxis regimens and treatment duration.