Due to the uncertain effect of anticoagulant therapy on the prognosis of patients with cirrhotic PVT, the usage of anticoagulants for cirrhotic PVT remains controversial. Besides, anticoagulants for cirrhotic PVT have a limited suitable population recommended by the guidelines [18], and the optimal anticoagulants remain undetermined. This is due to insufficient clinical data on the safety and efficacy of anticoagulants for cirrhotic PVT. We analyzed patients in our institution to understand the current situation of anticoagulants for cirrhotic PVT and provide more experience in anticoagulant therapy.
Spontaneous recanalization of PVT was observed in patients of the non-anticoagulant group, but the recanalization rate was higher in patients receiving anticoagulant therapy, which means anticoagulants appear effective for the treatment of cirrhotic PVT. The recanalization rate of the anticoagulant group in our study was lower than that found in a previous meta-analysis (66.2%) [14], which might be related to the dosage of anticoagulant regimens. In our study, rivaroxaban was the most commonly used anticoagulant, but only 3 patients received the therapeutic dose of 20mg qd, while most used 10mg qd. And the patients taking warfarin had an INR goal of 1.5–2.5. The inadequate anticoagulant dosage may be responsible for the low recanalization rate of PVT. There was no significant difference in PVT recanalization rate and bleeding rate between patients taking warfarin and rivaroxaban in our study. However, an RCT [16] suggested that rivaroxaban 10mg q12h had a higher rate of PVT recanalization than warfarin (complete response 70% vs 20%, P < 0.001). Thus, we need to clarify the relationship between the dosage and the efficacy and safety of different anticoagulants first, and then compare the differences among the anticoagulants.
Clinicians prefer to use low-dose anticoagulants, which may be due to the worry of bleeding complications. However, our study concluded that anticoagulants did not increase the rate of total bleeding, major bleeding, and variceal bleeding. This may indicate that anticoagulant therapy is safe for patients with cirrhotic PVT. ACG clinical guidelines [18] also indicated that anticoagulant therapy was not associated with an increased risk of variceal bleeding in patients with cirrhotic PVT, and the presence of gastroesophageal varices was not a contraindication to anticoagulant therapy. A previous meta-analysis [19] even concluded that anticoagulation can reduce the rate of variceal bleeding(OR 0.232, 95% CI 0.06–0.94, P = 0.04). The mechanism may be related to anticoagulants that can reduce pressure in oesophageal varices [20].
There is also uncertainty about the effect of anticoagulant therapy on the prognosis of patients with cirrhotic PVT. The presence of PVT increased the complexity of liver transplantation surgery and increased the risk of early mortality after liver transplantation [6]. However, it is not clear whether anticoagulant therapy affects patient outcomes in patients who have not undergone liver transplantation. A multicenter, long-term follow-up of cirrhotic PVT showed no significant difference in Kaplan-Meier survival curves of overall survival after 5 years of follow-up between the anticoagulant and non-anticoagulant groups (83% vs 70%, log-rank P = 0.1362). After 2 years of follow-up, there was also no difference in mortality between the two groups was observed in our study. A recent meta-analysis [21] showed that the survival rate of the anticoagulant group was higher than that of the non-anticoagulant group (OR 1.11, 95% CI 1.03–1.21, P = 0.010), but it was not clear whether patients underwent liver transplantation during the follow-up period. Therefore, more studies are needed to evaluate the efficacy and safety of anticoagulant therapy in patients with cirrhotic PVT who are not awaiting liver transplantation to guide the optimal anticoagulant therapy.
In terms of the prognosis of liver function, we observed that there was no significant difference in the baseline Child-Pugh score between the anticoagulant group and the non-anticoagulant group, but there was a significant difference in liver function score between the two groups at the end of follow-up. Child-Pugh grade C patients increased and grade A patients decreased in the non-anticoagulant group. An RCT study found [9] that the Child-Pugh score of patients after anticoagulant therapy was significantly improved compared with before (7 vs 6, P = 0.007). So anticoagulant therapy may have a beneficial effect on the liver function of patients with cirrhotic PVT. Besides, it is considered that the safety of DOACs in patients with Child-Pugh grade C needs to be evaluated. A Child-Pugh grade C patient included in our study had good safety and effectiveness after taking rivaroxaban for 8 months, but larger sample studies with larger sample sizes are still needed to collect more data on the safety of DOACs in those patients.
There were several limitations of our study. Firstly, this single-center study had a limited number of patients, which may lead to biased results. But it fulfilled the statistical demand. Secondly, anticoagulants therapy could increase levels of PT(s) and INR (part of Child-Pugh score and MELD score respectively), which may result in underestimation of liver function. But this is an inevitable confounding factor in the evaluation of liver function. Thirdly, we have followed patients for a median of 26 months, longer follow-ups are needed to observe the effect of anticoagulation on the mortality of patients with cirrhotic PVT.
In conclusion, anticoagulant therapy could increase the rate of PVT recanalization without increasing the rate of bleeding in patients with liver cirrhosis and could reduce the rate of variceal bleeding. Compared with the non-anticoagulant group, anticoagulant therapy may be beneficial to the liver function of patients with cirrhotic PVT. There was no significant difference in the safety and efficacy of different anticoagulants in the treatment of cirrhotic PVT. Further studies are needed to optimize the use of anticoagulants in patients with cirrhotic PVT.