Introduction: Advances in surgical techniques have significantly reduced vascular complications in pediatric liver transplantation, allowing transplantation in increasingly complex and smaller patients. This study evaluates risk factors for late portal vein thrombosis (PVT) in children undergoing living donor liver transplantation (LDLT).
Methods: A retrospective cohort study analyzed 702 children <10kg who underwent LDLT at our institution from June 2000 to June 2022. Patients were categorized into two groups: those with and without PVT. Additional subgroups were created based on the use of venous grafts (VG) for portal vein reconstruction. Preoperative and perioperative risk factors influencing PVT were assessed using univariate and multivariate analyses.
Results: Biliary atresia was the primary indication for transplantation in 80.2% of cases (n=563), and the recipient’s mean (SD) body weight was 7.2 Kg (1.3). The overall incidence of late PVT was 6.1%, . Among patients requiring reconstruction (n=224), deceased donor iliac vein (DDIV) was the most commonly used vascular graft (n=147, 65.6%), followed by living donor's gonadal vein (n=44), living donor’s inferior mesenteric vein (n=19), and the recipient’s internal jugular vein (n=11). Multivariate analysis identified two significant risk factors for PVT: venous graft use (p<0.001) and transplantation before 2011 (p=0.005). However, venous graft  type, VG preservation time, and VG ABO compatibility were not significant risk factors for PVT.
Conclusion: Venous graft use in portal vein reconstruction is associated with increased PVT risk. Smaller patients more frequently require vascular grafts, emphasizing the need for enhanced technical expertise to reduce complications. Notably, our evaluation of vascular graft characteristics did not identify a specific factor that significantly increased PVT risk. Further refinement of surgical techniques is essential to improving outcomes in this vulnerable population.