The percutaneous Greenfield filter: Outcomes and practice patterns

Objective: The percutaneous steel Greenfield filter (PSGF) is similar in ap pearance to the titanium Greenfield filter (TGF) but differs in the length and orientation of the attachment hooks and in the over-the-wire delivery s ystem. Because these differences improve ease of insertion and attachment, they may affect patient outcomes and physician practices. The purpose of th is study was to evaluate the performance of the PSGF relative to the TGF an d to determine whether there had been a change in physician practices. Methods: The Michigan Filter Registry contains data for a prospective cohor t of 2188 patients with Greenfield filters. Procedural and long-term outcom es for patients with a PSGF were abstracted. These events were compared wit h rates for Registry patients who had a TGF. Trends for indication for plac ement, delivery route, and filter location were also compared with publishe d series. Results: Since 1995, 600 PSGFs have been placed in 599 patients. A 1-year m ortality rate of 42% left 349 patients available for annual follow-up, and studies were completed for 231 (66%). Periprocedural events occurred in 2.5 % of cases with associated morbidity in 1.5%. The rate of new pulmonary emb olism was 2.6%, and vena caval patency was 98.3%. The combined rate of new venous thromboembolic events was 12.5%. Left-sided femoral vein placements increased to 20%, and the major indication for filter placement has become prophylaxis (46%). Conclusions: The PSGF is similar to the TGF with respect to patient outcome s, and it provides decreased rates of asymmetry along with excellent fixati on. The flexible carrier system has allowed more frequent access through th e left femoral vein. The ease of use and favorable patient outcomes have re sulted in more frequent placement for prophylactic indications.