Hepatic artery thrombosis (HAT) after liver transplantation is a severe complication that often requires retransplantation. The authors have adopted a different approach, aimed at treating the perioperative HAT complications aggressively and early, with ursodeoxycholic acid (UDCA), to try to preserve the original graft. Eighty-six liver transplants were performed in 73 children (age range, 4.5 months to 17.5 years; median, 2.6 years). HAT occurred eight times, in seven patients (9.3%). Patients with HAT were significantly younger and smaller (mean age, 0.8 +/- 0.4 v 4.8 +/- 5.3 years; P < .02; mean weight, 7.4 +/- 0.8 v 18.7 +/- 16.2 kg; P < .05). The incidence of HAT varied significantly according to the method of arterial reconstruction used: 4 of 16 (25%) when a donor iliac artery interposition graft to the aorta was used, 4 of 61 (6.6%) when the native hepatic artery was used, and 0 of 9 when the donor celiac axis was anastomosed directly to the aorta (P < .05). The incidence of HAT was not significantly different when reduced-size grafts were used. Early retransplantation was performed in three of the eight patients; two survived. All other patients were treated for 4 to 6 weeks with broad-spectrum antibiotics and amphotericin. Five patients were treated with UDCA, three immediately after the acute event and two after 4 and 6 months (respectively) post-HAT. The patients who had UDCA immediately post-HAT had histologically normal liver biopsy specimens. Results of liver function tests have been normal. One of these patients required transhepatic stenting of a common bile duct stricture for several months.(ABSTRACT TRUNCATED AT 250 WORDS)