One of the causes of
portal hypertension is portal vein
thrombosis (PVT). The aim of this study was to determine whether natural
anticoagulant deficiencies,
activated protein C resistance (APCR), and
factor V Leiden play a role in the development of PVT, leading to cavernous transformation of the portal vein (CTPV). Twenty-three patients with idiopathic CTPV (group 1) seen at Hacettepe University Hospital during the past 12 years were identified and prospectively studied. These 23 patients underwent a detailed hematological evaluation including measurement of
protein S,
protein C,
antithrombin III,
activated protein C resistance (APCR), and
factor V Leiden gene mutation. Additionally, all patients were tested for
anticardiolipin antibodies (ACA),
IgG,
IgM, and
lupus anticoagulant (LA). Natural
anticoagulants and APCR were measured using available commercial kits, and
factor V Leiden mutation (R506Q) was detected by Mnl I digestion of an amplified
factor V DNA fragment. All parameters were measured at least 6 months after the diagnosis of CTPV was established. No patient was on
anticoagulant or antiaggregant treatment while tested. The findings in these 23 patients were compared with those in 20 healthy control subjects (group 2), in whom all tests mentioned above were also performed. In 23 patients (group 1), who had no recognizable factor for portal vein
thrombosis, considerably natural
anticoagulant deficiencies and
factor V Leiden mutation positivity were found when we compare them to those healthy controls (group 2). The
protein C levels of six patients (26%), the
protein S levels of 10 patients (43.5%), and the
antithrombin III levels of five patients (26%) were lower than in control subjects. Two patients were found to have combined
protein S and
antithrombin III deficiency, and one had combined
protein S and C deficiency and APCR. APCR was detected in seven of the 23 patients, and six of these seven patients were found to have R506Q
factor V Leiden mutations. In group 1, ACA
IgG levels were higher in four patients (17%) and ACA
IgM level was higher in one (4%) compared with the control group. LA was positive in only one patient in group 1. Natural
anticoagulant deficiencies and
factor V Leiden mutation are strongly associated with PVT. The natural
anticoagulant deficiencies and APCR (almost totally caused by R506Q mutation) produce a favorable medium for
thrombus generation. PVT seems to be related to the natural
anticoagulant deficiencies and
factor V Leiden R506Q mutation. A combination of these defects increases the incidence of PVT and these factors should be evaluated carefully in patients with idiopathic CTPV.