Venous outflow obstruction in pediatric left lateral segment split liver transplantation

Background: Venous outflow obstruction (VOO) is a known cause of graft and patient loss after pediatric liver transplantation (LT). We analyzed the incidence, risk factors, diagnosis, management, and outcome of VOO in a large, consecutive series of left lateral segment (LLS) split LT with end-to-side triangular venous anastomosis. Methods: We evaluated data collected in our prospective databases relative to all consecutive pediatric liver transplants performed from January 2006 to December 2021. We included in this study children undergoing LLS split liver transplant with end-to-side triangular anastomosis. Diagnosis of VOO was based on clinical suspicion and radiological confirmation. Results: VOO occurred in 24/279 transplants (8.6%), and it was associated with lower graft weight (p = .04), re-transplantation (p = .008), and presence of two hepatic veins (p < .0001). In presence of two segmental veins' orifices, the type of reconstruction (single anastomosis after venoplasty or double anastomosis) was not significantly related to VOO (p = .87). Multivariable analysis indicated VOO as a risk factor for graft lost (hazard ratio 3.21, 95% confidence interval 1.22-8.46; p = .01). Percutaneous Transluminal Angioplasty (PTA) was effective in 17/22 (77%) transplants. Surgical anastomosis was redone in one case. Overall six grafts (25%) were lost. Conclusion: VOO after LLS split LT with end-to-side triangular anastomosis is an unusual but critical complication leading to graft loss in a quarter of cases. The occurrence of VOO was associated with lower graft weight, re-transplantation, and presence of two hepatic veins. PTA was safe and effective to restore proper venous outflow in most cases.