Risk Estimation And Management Of Intraoperative Low Portal Flow Velocity In Living Donor Liver Transplantation In Infants

Background & Objective: Living donor liver transplantation(LDLT)is a major form of pediatric liver transplantation and has become an effective treatment for various types of end-stage liver disease and metabolic diseases in children.However,due to the small caliber and short pedicle of children's portal vein(PV)as well as its mismatched size with the adult donors',the PV reconstruction is technically more challenging,which contributed to the high incidence of postoperative portal vein complications(PVC)and intraoperative low portal flow velocity(i LPFV)after the reconstruction.The study was aimed to explore the risk factors for the development of i LPFV and summarize an effective strategy to prevent and manage it.Because i LPFV usually occurred in younger infants,we limited our patients to 12 months of age.Methods: The clinical data of 283 infants(?12 months of age)who underwent LDLT from January 1,2015 to December 31,2016 in our center were retrospectively analyzed.Patient with intraoperative portal flow velocity less than10cm/s examined by Doppler ultrasound after portal vein reconstruction were divided into the i LPFV group.Other three patients who suffered acute portal vein blood flow <10cm/s on the postoperative day1(POD1)were also included in this group.Independent risk factors for i LPFV were identified by multivariate logistic regression analysis,and a risk index grading model was established to predict the its occurrence.Next,by reviewing all the preoperative preparation,intraoperative procedure and postoperative caring,we establish an integrated strategy based on the risk factors to manage the i LPFV.All the survival rates were calculated by the Kplan-Meier method and compared by Log-rank method.Results: There were 31 children(31/283,10.95%)in the i LPFV group.Preoperative low body weight(<6.65 kg),narrow portal vein(<4.45 mm),reversed portal flow and high graft-to-recipient weight ratio(GRWR)were identified by multivariate logistic regression to be the independent risk factors for i LPFV.With the increasing number of risk factors,the probability for developing i LPFV increased,too.With the managements of integrated strategy,all the cases of poor flow velocity were corrected with no obvious PVC and hemodynamic abnormalities observed during followup period.7 children in i LPFV group died within three months after surgery.No re-transplantation was performed.The 2-year survival rate of patients and grafts were 77.3% in i LPFV group,and 93% in Non-i LPFV group.As for the whole cohort,the overall 2-year survival rate of patient and graft were 91.1%.Conclusion: i LPFV can be used as a predictor of early death in infantile patients after LDLT.Patients with high risk of i LPFV need comprehensive measures to prevent and treat it.In addition,strengthen nursing and supportive care were necessary after the surgery for those children.