Venous interruption as prophylaxis of pulmonary embolism: vena cava filters.

Interruption of vena cava for prevention of pulmonary embolism (PE) was achieved in the past with surgical ligation or placement of clips outside the infrarenal vena cava. At present, this procedure is performed with percutaneous insertion of vena cava filters. Vena cava filters can be permanent or temporary, catheter-retrievable. Main indications for placement of a vena cava filter are: contraindication for anticoagulant therapy in patients with severe PE in whom a further embolic episode would be fatal or patients with PE (or its recurrence) undergoing adequate anticoagulant therapy. Temporary filters are reserved to patients where the risk of PE is limited in time as in posttraumatic, post-partum or postoperative thromboembolism. The incidence of recurrence after placement of a vena cava filter varies between 0.5 and 7%. Procedure-associated complications are usually mild. However, severe complications as filter migration into the pulmonary artery or vena cava perforation were described. Our experience concerns the insertion of 61 vena cava filters (47 permanent and 14 temporary). Indications were as follows: iliofemoral thrombosis at embolic risk (37 cases), contraindication for anticoagulant therapy in the presence of deep vein thrombosis with embolic risk (7 cases), protection during fibrinolytic therapy (3 cases), PE during anticoagulant therapy (5 cases) complications of anticoagulant therapy which required discontinuation (5 cases), prophylaxis in view of surgery at high risk for PE (2 cases), protection for surgical venous thrombectomy (2 cases). Mortality was nil. Clinically evident PE was not observed in any patient in whom vena cava filter was inserted. Complications were mild and asymptomatic. Vena cava filters represent an effective prevention of PE together with medical and surgical treatment. At present, problems of this procedure are not technical but rather concern correct indications. Interruption of vena cava is effective if planned within a global strategy for prevention of thromboembolism.