Fig. 1. Normal cavogram before insertion of the filter.	Fig. 2. Incompletely formed Nitinol filter.

Case Reference No. CC-797-01 A 49-year-old woman with ovarian cancer was found to have large bilateral common femoral venous thrombi. Prior to gynecologic surgery, IVC filter placement was requested to avoid anticoagulation. The jugular approach was chosen. The initial cavogram (Fig. 1) showed a normal IVC. A Nitinol filter was deployed. Although the lower struts came out normally, the upper basket failed to form and remained elongated (Fig. 2). An Amplatz snare was used to grab the top end of the filter (Fig. 3) and to push the filter into its proper shape. This maneuver succeeded in forming the dome but may have caused one of the struts to perforate the caval wall (Fig. 4). The patient tolerated the procedure with no pain or other apparent sequelae from strut perforation.

Fig. 3. Grabbing the filter with the snare. Fig. 4. After manipulation of the filter, the strut (arrow) perforates the caval wall.

Questions 1) Given that the incompletely formed filter is not that different in shape from another filter design (the Gunther filter), would anyone have left it alone? 2) Has the filtration capability of the Nitinol filter been studied in this configuration? Related cases: Case 1097_01 -- Gonadal vein placement of inferior vena cava filter