Association between Portal Vein Thrombosis and Survival of Liver Transplant Recipients: a Systematic Review and Meta-analysis of Observational Studies

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Xingshun Qi1,2, Junna Dai1, Jia Jia2,3, Weirong Ren2,4, Man Yang2,5, Hongyu Li1, Daiming Fan2, Xiaozhong Guo1

1) Liver Cirrhosis Study Group, Department of Gastroenterology, General Hospital of Shenyang Military Area, Shenyang;
2) Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an;
3) Department of Emergency, Shaanxi Provincial Peoples' Hospital, Xi'an;
4) Department of Digestive Diseases, Sanmenxia Central Hospital, Henan University of Science and Technology, Xiaoshan Road, Sanmenxia;
5) Department of Gastroenterology, Songgang People's Hospital, Songgang, Shenzhen, China.



Background & Aims:
Portal vein thrombosis (PVT) increases the technical complexity of liver transplantation (LT). This systematic review and meta-analysis aim to analyze the association of pre-LT PVT with the overall survival after LT.

PubMed, EMBASE, and Cochrane library databases were used to search for papers related to the association between pre-LT PVT and survival of LT recipients. The differences in the survival rates between the LT recipients with and without pre-LT PVT were expressed as odds ratios (ORs) with 95% confidence intervals (CIs).

Twenty-seven papers were included. Overall meta-analysis showed that the total LT recipients with pre-LT PVT had a significantly lower 1-year survival rate than those without pre-LT PVT (OR=0.733, 95%CI=0.621-0.865; P=0.0002). But no statistically significant difference was observed in the in-hospital (OR=0.713, 95%CI=0.343-1.482; P=0.365), 1-month (OR=0.679, 95%CI=0.345-1.333; P=0.261), or 5-year survival rate (OR=0.788, 95%CI=0.587-1.058; P=0.113). Additionally, the 1-year survival rate was significantly lower in the LT recipients with complete PVT than in those without PVT (OR=0.503, 95%CI=0.295-0.858; P=0.012). However, no statistically significant difference in the 1-year survival rate between them was observed in the meta-analysis of high-quality studies (OR=0.899, 95%CI=0.657-1.230; P=0.505) or that of studies in which LT was performed after 2000 (OR=0.783, 95%CI=0.566-1.083; P=0.140).

Conclusion. Pre-LT PVT, especially complete PVT, decreased the 1-year survival rate after LT. However, the detrimental effect of pre-LT PVT on the survival of LT recipients became inconclusive in high-quality studies. Additionally, further well-designed cohort studies should validate the association in patients undergoing LT during the latter years.

Key words:
prognosis - survival - portal vein thrombosis - liver cirrhosis - liver transplantation.