Incidence and factors predictive of recurrent thrombosis in people with non-cirrhotic portal vein thrombosis.

ABSTRACT

BACKGROUND & AIMS: Clinical guidelines do not recommend long-term anticoagulation in non-cirrhotic splanchnic vein thrombosis (NC-SVT) without underlying thrombophilia because it is assumed that there is a very low risk of recurrent thrombosis (RT). Our first aim was to describe the incidence of RT in people with NC-SVT without an indication for long-term anticoagulation. The second aim was to identify RT risk factors and afterwards verify them in a validation cohort. METHODS: This is a multicentre, retrospective observational study evaluating risk factors for RT in 64 people with NC-SVT of idiopathic/local factor aetiology. In a subgroup of 48 individuals, the potential value of additional thrombophilic parameters to predict RT was analysed. Findings were validated in 70 individuals with idiopathic/local factor NC-SVT. RESULTS: Of the 64 participants in the training cohort, 17 (26%) presented splanchnic and/or extrasplanchnic RT (overall-RT) during follow-up (cumulative incidence 2, 10, 19, and 34% at 1, 2, 5, and 10 years, respectively). In addition, 53% of people with splanchnic RT were asymptomatic. No clinical or biochemical parameters predicted overall-RT. However, in the 48 people with an additional comprehensive thrombophilic study, factor VIII ≥150% was the only independent factor predicting overall-RT (hazard ratio 7.10, 95% CI 2.17-23.17, p <0.01). In the validation cohort, 19 individuals (27%) presented overall-RT, and it was also independently predicted by factor VIII >150% (hazard ratio 3.71, 95% CI 1.31-10.5, p <0.01). The predictive value of factor VIII was confirmed in both people with idiopathic/local factor aetiology associated NC-SVT. CONCLUSIONS: People with idiopathic/local factor NC-SVT are at risk of overall-RT. Splanchnic RT can be asymptomatic and requires screening for its detection. Values of factor VIII ≥150% may help identify individuals at high risk of overall-RT who could benefit from long-term anticoagulation. IMPACT AND IMPLICATIONS People with idiopathic/isolated local factor non-cirrhotic portal vein thrombosis were previously thought to be at minimal risk of re-thrombosis and therefore did not receive scheduled follow-up. The results of this study are of special interest for hepatologists treating people with non-cirrhotic splanchnic thrombosis, as they show a 25% incidence of re-thrombosis and support the close follow-up of people with factor VIII >150% to ensure the early identification of new thrombotic events.