Absence of large portal collateral vessels is associated with spontaneous improvement of cirrhotic portal vein thrombosis

Portal vein thrombosis (PVT) is a major complication in patients with liver cirrhosis (LC). In some cases, PVT decreases spontaneously, but the factors that predict this are still not fully understood.This was a retrospective, multicenter study that included 77 consecutive patients with cirrhotic PVT. Forty-eight patients did not undergo anticoagulation and 29 patients did between the time of the first diagnosis of PVT and the follow-up radiological imaging undertaken 1-6 months later. A complete disappearance and 25% shrinkage of PVT was defined as complete remission (CR) and partial remission (PR), respectively. Portosystemic collateral vessels larger than 9 mm in diameter were defined as large collateral vessels.Complete remission + PR was found in 37.5% of the anticoagulation-naïve patients. On univariate analysis, the absence of large collateral vessels, absence of PVT in the main trunk of the portal vein, a high platelet count, and a low FIB-4 index were significant factors associated with CR + PR. On multivariate analysis, the absence of large collateral vessels was the unique factor associated with CR + PR of PVT (odds ratio 5.9; 95% confidence interval, 1.73-20.1). The CR + PR rate for anticoagulated patients was 44.8%. However, no predictors for a good treatment effect of anticoagulation for PVT were identified.Spontaneous improvement of PVT in patients with LC can be expected when large collateral vessels are absent. For these patients, the option of observing them without anticoagulation can be considered in expectation of spontaneous reduction of PVT.