"Etiology of Non-Cirrhotic Portal Vein Thrombosis in Adults: Experience of 12 Years in a Chilean University Hospital"

Introduction: Portal Vein Thrombosis (PVT) is a rare disease primarily caused by a thrombotic obstruction in the origin of portal vein in extrahepatic portion. PVT is a frequent complication in advanced chronic liver disease (CLD), but the etiology and complications of non-CLD PVT (nPVT) are not well understood. The etiology of nPVT is heterogeneous and involves both local and systemic prothrombotic factors such as abdominal inflammatory processes, inherited and acquired thrombophilia, and JAK 2 positive mieloproliferative neoplasm (MPN).

Methods: The aim of this study was to evaluate etiological and prognostic factors in nPVT patients in chilean population. All patients referred to University of Chile Clinical Hospital between January 2002 and January 2012 with nPTV diagnosis were included in this study, with no previous history of solid or hematologic malignancy or CLD. We studied demographic characteristics, risk factors and in-hospital mortality rate. Statistical tests were two-tailed with the level of significance set at p<0.05, and we use analysis multivariate. The presence of the JAK2 mutation was determined by polymerase chain reaction in patients from whom DNA was available. It was decided that CLD was not possible through clinical history, abdominal ultrasound and liver enzymes. Screening for Thrombophilia was made with C and S protein, prothrombin gene mutation, V Leyden factor mutation, hyperhomocysteinemia, AT-III deficit and screening for anti-phospholipid syndrome.

Results: 265.089 adult patients were hospitalized at Clinical Hospital, University of Chile between 2002 and 2012, and 119 had nPVT diagnoses (0.04%). Median age at the diagnosis was 56.8± 2.43 years, with 52.1% of female sex. 15.9% died at the hospital. Thrombophilia was diagnosed in 33 patients (27.73%), newly diagnosed solid tumors in 16 patients (13.44%) and JAK 2 positive MPN in 4 patients. In analysis multivariate, patients with nPVT and Thrombophilia diagnosis was significantly associated to previous deep venous thrombosis diagnosis (OR 7.78, p=0.0007), female sex (OR 3.06, p=0.01) and age below 50 years (OR 1.82, p=0.03)

Conclusions: nPTV is a rare disorder, and its development is associated to the presence of inflammatory intra-abdominal process, newly diagnosed solid tumors, MPN and Thrombophilia. The previous deep venous thrombosis diagnosis, female sex and age below 50 years are associated to thrombophilia diagnosis.