Ticagrelor in Post-transplant Patients With Pediatric Hepatic Artery Thrombosis (HAT)

Inclusion Criteria: * age from 2 months to 5 years old. * voluntary participation in clinical trials, and informed consent; * Contrast- Enhanced Ultrasonography proved HAT Exclusion Criteria: * History of sensitivity to study medications or any of their excipients * Renal failure (eGFR \<30 or requiring dialysis) * A known bleeding diathesis, hemostatic or coagulation disorder, or prior major bleeding * Prior stroke * Active pathological bleeding * History of intracranial haemorrhage * Life expectancy \<12 months based on investigator's judgement * Patients considered to be at risk of bradycardic events (e.g., known sick sinus syndrome or second or third degree atrioventricular \[AV)\] block) unless already treated with a permanent pacemaker * Anemia (hematocrit \< 27%) * Platelet count \< 100,000/ml * Concomitant use of strong CYP 3A inhibitors or inducers