THE TREATMENT OF FREE-FLOATING VENOUS THROMBI

Among patients with deep vein thrombosis (DVT), the frequency of pulmonary embolism seems conditioned by the location of DVT and thrombus adherence. Consequently, patients with free-floating iliac thrombus are at high risk of life-threatening pulmonary embolism. As regards their definition, non adherent thrombus and free-floating thrombus are not synonymous. Non adherent thrombi are usual in recent DVT and have the same prognosis and treatment as common DVT. The term of free-floating thrombi should be reserved for the iliac location when a small area of the thrombus is attached to the iliac vessel wall but the rest of it does not adhere to the wall. At present, venography is the gold standard for diagnosis but duplex scanning and scanner or magnetic resonance imaging should also be evaluated for this purpose. The treatment comprizes the usual anticoagulant therapy with heparin and a specific treatment for the free-floating thrombus. 1) Vena cava filter is a rapid safe solution that avoids severe pulmonary embolism, but in the case of thrombus detachment, vena cava obliteration might occur with the subsequent risk of severe bilateral venous stasis and insufficiency. The indications for such treatment might be elderly patients in a poor general condition. 2) Venous thrombectomy. Venous thrombectomy only removes the free part of the thrombus, thus preserving the contralateral iliac vein from further complications. A clip is positioned on the inferior vena cava. 3) Protected fibrinolysis. The latest catheters allow transient vena cava filter device placement. Thrombolytic therapy with rTPa might achieve thrombolysis and subsequently restore the venous circulation. At the end of this treatment, the transient vena cava filter is removed and anticoagulant treatment with heparin is continued. This new and promising treatment for free-floating iliac venous thrombi urgently requires multicenter evaluation.