Go With the Flow: Hepatic Hemodynamics Impact Outcomes in Pediatric Liver Transplant

BACKGROUND: Vascular complications persist as a challenging barrier to pediatric liver transplantation. With an incidence of 5%-10%, portal venous and hepatic arterial thromboses remain a major cause for early graft loss in this population. Real-time evaluation of flow parameters at various time points in the transplant course offers an ability to diagnose and even prevent such complications, and may consequently enhance long-term graft and recipient outcomes. METHODS: This review summarizes clinical studies describing liver hemodynamics in pediatric recipients and the utilization of flow parameters for the hepatic artery, portal vein, and hepatic vein. RESULTS: Preoperative parameters by doppler ultrasonography (DUS) predict the need for portal vein reconstruction which can assist with perioperative planning. Intraoperatively, real-time assessment of flow parameters predicts vascular complications and assists in evaluating the adequacy of graft inflow modulation (GIM). Postoperative surveillance remains critical to detection of both venous and arterial thrombosis and stenosis, but normal measurement ranges often vary based on patient age, underlying liver disease diagnosis, type of graft, and time from transplantation. CONCLUSIONS: Future studies are needed to evaluate the most effective screening protocols and define intra-operative and post-operative measurements that should prompt surgeons to consider intervention in this vulnerable population.