Simon nitinol vena cava filters: effectiveness and complications.

Purpose: The aim of this retrospective analysis was to evaluate the clinical safety and effectiveness of the Simon Nitinol inferior vena cava filter (SNF) for prevention of pulmonary embolism. Patients and Methods: 117 patients (63 male, 54 female; aged 58.38 +/- 14.59 years) underwent percutaneous implantation of an SNF from 1993 through 1999. Patient reports were retrospectively analysed for complications during and after implantation and deep venous thrombosis (DVT) and pulmonary embolism before and after implantation. Helical-CT with contrast media and plain abdominal radiography were performed on 35 patients, helical-CT alone on two patients. We checked the position and configuration of the SNF and looked for a perforation of the filter legs through the wall of the inferior vena cava (IVC). The IVC and deep pelvic veins were analysed for patency. Results: During implantation 10 of 117 (9%) patients had minor complications, major complications were reported in 0.9% (1/117). There was no significant increase in thrombosis of the deep pelvic veins and the IVC after implantation. Pulmonary re-embolism (PE) was documented in 9 out of 117 patients (7.7%). One out of the 35 examined patients (2.9%) showed a single strut fracture of the SNF. Tilting more than 15(-) was seen in 7 out of 37 patients (19%). Dislocation of the SNF more than 10 mm occurred in one out of 35 patients (2.9%), perforation through the wall of the IVC in all 37 patients. We found no occlusion of the IVC. Conclusion: The SNF is easy and safe to implant and successfully prevents pulmonary embolism. in our study the rate of well documented pulmonary re-embolism (7.7%) is satisfactory. Except for the high perforation rate through the wall of the IVC (100%, but without clinical relevance), complication rates during and after implantation of the SNF are low compared with other filter types.