End stage liver disease is prone to thrombocytopenia. This study is a multi-center, randomized, prospective, randomized controlled Phase IV Clinical trial to discuss the Efficacy and Safety of Avatrombopag in Patients with End-stage Liver Disease and Thrombocytopenia.

End stage liver disease is prone to thrombocytopenia. This study aims to discuss the Efficacy and Safety of Avatrombopag in Patients with End-stage Liver Disease and Thrombocytopenia in a multicenter, prospective, randomized controlled trial. The patients were divided into one of the groups according to if receiving avatrombopag. Avatrombopag was taken to maintain platelet count 50~100×10^9/L. Starting dose is recommended according to the patient's baseline platelet count level. Routine treatment was taken in the Control group and Interventional group. This trial will take about 2 to 2.5 years from the first participant signing an informed consent form (ICF) until all study-related telephone follow-ups or visits end.

Inclusion Criteria:

1. Men and women greater than or equal to 18 years of age;
2. Baseline platelet count <50×10^9/L;
3. End-stage liver disease, including acute-on-chronic liver failure, acute decompensation of liver cirrhosis, chronic liver failure;
4. Women of childbearing potential must agree to use a highly effective method of contraception from the beginning of Baseline Visit until the end of treatment (includes implantable contraception, injectable contraception, hormonal combination contraception [including vaginal rings], intra-uterine devices or vasectomy). The barrier contraception with or without spermicide alone, double barrier contraception and oral contraceptives are inadequate;
5. Subject is able to understand the study and willing to follow the protocol and sign informed consent voluntarily before Baseline Visit;
6. Subject meet the criteria according to the opinion of the researchers.

Exclusion Criteria:

1. Subject has a history of arterial or venous thrombosis within the previous 6 months of baseline;
2. Known portal vein blood flow velocity rate <10 cm/second or previous occurrence of a portal vein thrombosis within 6 months of Baseline;
3. Known any history of primary blood (e.g, immune thrombocytopenia, myelodysplastic syndrome, aplastic anemia);
4. Subject has a known medical history of genetic prothrombotic syndromes (e.g, Factor V Leiden prothrombin G20210A, antithrombin III (AT III) deficiency);
5. Subject has a recent history (within the previous 6 months) of significant cardiovascular diseases (e.g., exacerbation of congestive heart failure, arrhythmias known to increase the risk of thromboembolic events [e.g. atrial fibrillation], coronary or peripheral artery stent placement or angioplasty, and coronary or peripheral artery bypass grafting);
6. Female subjects who are lactating or pregnant at the Baseline Visit (as documented by a positive serum beta-human chorionic gonadotropin [β-hCG] test with a minimum sensitivity of 25 IU/L or equivalent units of β-hCG) or are planning to become pregnant during the study;
7. The subject has a hypersensitivity to Avatrombopag or any of its excipients;
8. Subjects with drug-induced thrombocytopenia;
9. Subjects whose Life expectation ≤6 months;
10. Subject with a current malignancy;
11. Subjects with HIV infection;
12. At screening, active infection was not effectively controlled by systemic antibiotic therapy;
13. The Investigator believe that any accompanying medical history may affect the safety of the subjects to complete the study;
14. The Investigator believe that there are any other factors that are not suitable for inclusion or affect participation or completion of the study;
15. Subject is enrolled in another clinical study with any investigational drug or device within previous 30 days of the Baseline Visit, but are allowed to participate in observational studies.