Evolution of a new device for the prevention of pulmonary embolism.

The embolus trap (ET) is a new device that interrupts the inferior vena cava (IVC) for the prevention of pulmonary embolism. It has a central column from which six wires extend in two tiers. The adjacent wires are formed into loops with hooks at the distal ends that grip the vein wall. Each tier contains three wire loops, and the loops are staggered circumferentially between the tiers. The ET was implanted into the IVC in 26 dogs via a femoral or jugular venotomy. IVC patency was evaluated by venacavagrams. Autologous clots were embolized via the femoral vein to test the efficacy of the ET. The animals were followed for 1 to 4 months prior to postmortem examination. The ET remained patent in all animals and consistently trapped the thromboemboli while preserving blood flow. Lysis of the trapped emboli was observed in 4 to 6 weeks. There was no evidence of malpositioning, penetration through the vein wall, or migration of the ET.