Prediction of hepatic artery occlusion after liver transplantation by ultrasound characteristics and clinical risk factors.

Background: Hepatic artery occlusion (HAO) after liver transplantation (LT) is a devastating complication, resulting in early graft loss and reduced overall survival. Ultrasound is an established assessment method for HAO in patients following LT, especially those with complex hepatic artery reconstruction.

Aim: To investigate the ultrasound characteristics and analyze the risk factors associated with HAO in patients after LT.

Methods: We retrospectively analyzed the ultrasound characteristics and the clinic risk factors associated with HAO in 400 adult LT patients who were enrolled and treated at the Third People's Hospital of Shenzhen between November 2016 and July 2022. Fourteen patients diagnosed with acute HAO (A-HAO) by surgery and fifteen diagnosed with chronic HAO (C-HAO) were included. A control group of 33 patients without HAO complications during the same period were randomly selected using a random number table. All patients underwent an ultrasonography examination. Parameters including resistance index (RI), peak systolic velocity (PSV), and portal vein velocity (PVV) were compared across the groups. Additionally, basic clinical data were collected for all patients, including gender, age, primary diagnosis, D-dimer concentration, total operation time, cold ischemia time, hot ischemia time, intraoperative blood loss and transfusion, intraoperative urine volume, infusion, model for end-stage liver disease (MELD) score, and whether complex hepatic artery reconstructions were performed. Furthermore, risk factors influencing HAO formation after LT were analyzed.

Results: Compared to the non-HAO group, PVV and RI were higher in the A-HAO group, while PSV was lower. Conversely, both PSV and RI were lower in the C-HAO group compared to the non-HAO group. The proportion of patients undergoing complex hepatic artery reconstructions and the gamma-glutamyltransferase (GGT) level before occlusion were significantly higher in the A-HAO group compared to the non-HAO group. However, there were no distinct differences between the two groups in D-dimer, MELD score, pre-occlusion alanine transaminase and aspartate transaminase levels, or intraoperative conditions.

Conclusion: Ultrasound features of the hepatic artery before occlusion are significantly associated with postoperative HAO development. Additionally, complex hepatic artery reconstructions, defined as revascularization of the graft requiring additional anastomosis between donor hepatic arteries, constitute a risk factor for A-HAO. Besides, abnormal pre-occlusion GGT elevation is an important biochemical indicator. Therefore, ultrasound examination serves as an important tool for screening HAO, especially in patients with the identified risk factors.