Heparin-induced thrombocytopenia type II (HIT II) is a rare immune-mediated complication of heparin. The diagnosis of HIT is considered in patients exposed to heparin, presenting with thrombocytopenia and thrombosis.

We present two cases with massive pulmonary embolism and HIT, successfully treated with the administration of fondaparinux, an alternative anticoagulant, combined with the insertion of an inferior vena cava filter for the prevention of new thromboembolic events. The two cases supplement the available data of the use of fondaparinux in patients with HIT and pulmonary embolism, before further large studies establish its efficacy and safety in this group of patients. Moreover, the management of these patients reveals the need for future evaluation of the combined therapy of alternative anticoagulant agents with the placement of vena cava filters.