Optimal central trapping (OPCETRA) vena caval filter: results of experimental studies

The authors present the in vitro and in vivo results of use of a new vena caval filter, the optimal central trapping (OPCETRA) filter. The in vitro study was designed to compare the clot-trapping effectiveness of three filters: the OPCETRA, the stainless steel Greenfield, and the original Vena Tech-LGM. Standardized 3-mm, 5-mm, and 7-mm clots were captured in 66%, 100%, and 100% of cases, respectively, with the OPCETRA filter; in 34%, 82%, and 100% of cases with the Greenfield filter; and in 50%, 100%, and 100% of cases with the LGM filter. When filters were tilted 15 degrees, 100% of the 5-mm clots were trapped with the OPCETRA filter versus 50% with the Greenfield (P < 1.04 x 10(-9)) and 70% with the LGM (P < 1.78 x 10(-5)) filters. The in vivo animal study was designed to confirm ease of placement, tolerance, and effectiveness of the OPCETRA filter in sheep. Animals were separated into two groups: Group 1 underwent embolization through the femoral vein 40 days after filter implantation and were killed immediately; group 2 underwent embolization at 90 days and were killed 8 days later. In all cases pathologic analysis on the vena cava wall was performed after resection. The in vivo study demonstrated no tilting or migration with the OPCETRA filter. These encouraging results can be explained by the filter's hourglass shape, the number of arms, and the slow release of the filter at insertion.(ABSTRACT TRUNCATED AT 250 WORDS)