[Antiphospholipid syndrome and venous thromboembolism: the role of congenital thrombophilia]

Abstract

The antiphospholipid syndrome is associated with complications of pregnancy or venous or arterial thrombosis in the presence of antiphospholipid antibodies. Venous thromboembolism is the most common clinical feature. Pathogenetic mechanisms underlying the syndrome are not completely understood and several hypotheses have been raised. Secondary prophylaxis after venous thromboembolism episodes requires oral anticoagulants (prothrombin time-international normalized ratio 2-3) for 6 to 12 months. More intensive anticoagulant regimens are indicated in case of recurrence. A longer or life-long course of treatment is indicated in patients with recurrent or life-threatening events or in the presence of high titers of antiphospholipid antibodies. Among risk factors for venous thromboembolism, inherited thrombophilia is recently described, such as defects of the physiological coagulation inhibitors, genetic mutations of factor V and factor II of the coagulation cascade and hyperhomocysteinemia. High levels of factor VIII, factor IX and lipoprotein(a) have recently been proposed as new risk factors for venous thromboembolism. The coexistence of inherited thrombophilia seems to enhance the thrombogenic risk, in particular in the venous vascular bed. The new insights into the diagnosis of inherited thrombophilia could allow a better evaluation of the thrombotic risk, leading to tailor the prophylactic strategy.