Abstract
Combined thrombophilia represents 7.8-8.3% of the patients with thrombophilia and confers a higher risk for thrombosis development and recurrence. Here, we present a 17-year-old boy carrier of three congenital thrombophilias, two severe (type I antithrombin deficiency and type I protein S deficiency) and one prothrombotic polymorphism (prothrombin G20210A), all in heterozygosis. He developed an extensive deep venous thrombosis in lower left limb, reaching proximal inferior vena cava and contralateral iliac vein, in the setting of prolonged rest. Endovascular therapy with local thrombolytic agent infusion followed by mechanical thrombectomy was performed, achieving a favorable clinical and radiological evolution. Antithrombin replacement to achieve levels between 80% and 120% with heparin administration was used during the endovascular procedure. The patient is currently asymptomatic and maintains indefinite anticoagulation with warfarin, keeping an appropriate anticoagulation range (international normalized range between 2.5 and 3.5).