The goal of this observational study is to investigate the correlation between portal vein thrombosis (PVT) and the prognosis of liver transplantation. The main questions it aims to address are:

What is the prevalence of PVT? What are the risk factors associated with PVT? What is the prognostic impact of preoperative PVT on liver transplantation?

Participants are divided into two groups: the PVT group and the non-PVT group. The investigators will comparatively analyze the data of both groups, estimate the prevalence and risk factors of PVT, construct a predictive model for PVT that is applicable in clinical settings, and clarify the prognostic effects of PVT.

The investigators aim to investigate the prevalence and risk factors of PVT, to develop a novel grading or rating system for PVT, and to explore the prognostic impact of preoperative PVT in liver transplantation.

The investigators will:

Recruit patients according to the inclusion/exclusion criteria and obtain signed informed consents. They will collect demographic and laboratory characteristics and classify patients into the PVT group and the non-PVT group based on preoperative ultrasound and/or computed tomography.

Collect patients' perioperative medical imaging, surgical procedures, pathology reports, postoperative treatments, follow-up data, and clinical endpoints.

Comparatively analyze the data of the PVT and non-PVT groups, estimate the prevalence and risk factors of PVT, construct a predictive model for PVT that is applicable in clinical settings, clarify the prognostic effects of PVT, and propose a grading/rating system for PVT.

Inclusion Criteria:

1. Liver transplantation recipients
2. Aged 18 years or older.

Exclusion Criteria:

1. Retransplantation
2. Multi-organ transplantation
3. Portal vein tumor thrombus

Patients who underwent in situ liver transplantation at the Liver Transplantation Center of Beijing Friendship Hospital affiliated with Capital Medical University from 2016-1-1 to 2025-12-31