[Thrombophilic conditions in the pathogenesis of venous thromboembolism]

Thrombophilic conditions are congenital or acquired hemostatic disorders pathophysiologically or statistically associated with higher risk of thrombosis. Their most important clinical manifestation is venous thromboembolism. In more than 50% of persons with non-induced thrombosis, some of the known thrombophilias can be found. Persons with congenital thrombophilias have, contrary to those without any thrombophilias, most of all an increased risk of an initial thromboembolic event while the impact of congenital thrombophilic conditions on their recurrence is not so clear. In patients with idiopathic thrombosis is the risk of recurrence 7-10% a year even at the absence of known thrombophilias. The risk of a recurrent event is influenced by a set of other factors (prevailing or undetected trigger factor, proximal thrombosis and pulmonary embolism, incomplete rechanneling of a thrombotic vein, presence of some thrombophilias, high level of D-dimers after discontinuation of the anticoagulant treatment). Their identification and consequent monitoring are decisive in the choice of an optimum treatment and the duration of their administration in secondary prevention of venous thromboembolism. In the primary venous thrombosis prevention, the knowledge of general trigger factors and the individual risk characteristics of the given patient is important, which means also timely detection of thrombophilic conditions in patients who profit from it, i.e. if they display at least medium probability of detection. A universal long-term prophylaxis in so far asymptomatic carriers of congenital thrombophilias is not indicated with regard to potential complications of anticoagulant treatment. Women with thrombophilic disorders are under an increased risk of a thromboembolic event when using hormonal contraceptives and during pregnancy. There is also a higher incidence of pregnancy complications connected with disorders in blood circulation of placental vascular tree.