What are G2 and G2 Xinferior vena cava (IVC) filters?

Updated: Oct 31, 2020
  • Author: Gary P Siskin, MD; Chief Editor: Kyung J Cho, MD, FACR, FSIR  more...
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Recovery G2/G2 & G2 X filters

The Recovery G2 (or simply G2) and G2 X filters are modifications of the original Recovery filter. [80] These were approved by the FDA in 2008 and 2009, respectively.

The redesigned G2 filter has enhanced fracture resistance, better centering, improved fixation hooks, and longer legs with a wider span to reduce migration for IVCs up to 28 mm diameter. It is packaged separately for femoral and jugular approaches. The femoral kit has a 7F ID introducer sheath, whereas the jugular kit has a 10F ID set. The deployed height is 42 mm.

The retrieval set is the same as for the original Recovery filter. The G2 X filter has a hook at the apex, and is therefore retrievable by both the snare technique or with the cone retrieval kit.

Kim et al reported 5 new, symptomatic PE (6.5%) in 77 G2 filters placed. [50] In 2008, of 59 patients evaluated, Oliva et al reported 100% success for retrieval in 51 patients, with a mean dwell time of 53.4 days (range, 7-242 d). [81] Of these, 8 of 59 cases showed large trapped thrombi during cavography. Oliva et al reported 9 of 51 (18%) patients with IVC wall penetration and 6 of 51 (12%) patients with filter tilt greater than 15o. [81] There were no fractures or cranial migrations, but 2 caudal migrations occurred.

Charles et al reported filter tilt in 5 (18.5%) of their 27 patients. [82] In 2009, Binkert at al reported 15% filter tilts, 12% caudal migrations, and 1.2% filter fractures in 85 patients on a 6-month follow up. [83] Of the 61 patients referred for retrieval, 16 (26%) showed presumed penetration cavography, and 14 of 16 had successful retrieval. [83]

In the same year, Cantwell et al reported no filter fractures in their series of patients that compared the Recovery and G2 filters. [79] They further concluded that the G2 had less filter tilt but a higher rate of caudal migration than the Recovery filter. [79] Lynch and Kekulawela reported 6 (3.4%) filter fractures in 174 G2 filters placed, all of which were implanted for over 180 days. [84] They observed 76 of 174 (44%) cases of presumed caval penetration during removal. [84]

There have also been 2 reports of intraventricular migration. [85, 86]

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