Limb asymmetry in titanium Greenfield filters: clinically significant?

PURPOSE: The purpose of this study was to determine the outcomes for patients with titanium Greenfield vena caval filters (TGFs) and, in particular, to evaluate the effect of filter leg distribution on recurrent pulmonary embolism (PE) and caval occlusion.

METHODS: Physical examination, abdominal plain films, and duplex ultrasound examinations of the inferior vena cava and lower extremities were obtained annually and recorded in a Filter Database.

RESULTS: Seven hundred eighty-three TGFs have been placed since 1989. Follow-up was available for 373 patients, or 65% of the surviving patients, over 1 to 84 months (mean, 33 months). Asymmetry was identified in 42 placements (5%), and 35 of these patients had at least one follow-up examination. The overall incidence of recurrent PE was 3.2% (12 of 373), whereas the caval patency rate was 97.8% (265 of 271). These outcomes were not significantly different for patients who had asymmetric filters (p = 0.1 and 0.18, respectively).

CONCLUSIONS: Filter leg distribution does not appear to be associated with an increased incidence of recurrent PE or caval occlusion. These data support earlier in vitro findings. The long-term results with the TGF are comparable with the results of the original stainless steel Greenfield filter.