Case 1. A 48-year-old man with liver cirrhosis which led to massive variceal bleeding was referred to us for a transjugular intrahepatic portosystemic shunt (TIPS) procedure. After accessing the portal venous system via the right internal jugular route using a Colapinto transjugular cholangiography/liver biopsy set (Cook, Bloomington, Ind., U.S.A.), we dilated the parenchymal tract between the middle hepatic and left portal vein using a 10 mm-diameter Ultrathin Diamond balloon catheter (Medi-Tech/Boston Scientific, Watertown, Mass., U.S.A.). We tried to place a 10 mm-diameter, 8 cm-long Niti-S stent (Taewoong, Seoul, Korea) in the tract, but during deployment it migrated caudad to the main portal vein (Fig. 4A). A guidewire was inserted into the stent's central lumen, and an Amplatz gooseneck snare, its loop 25 mm in diameter, was introduced over it and positioned around the stent (Fig. 4B). After capturing and pulling the far proximal end of the stent by tightening the loop (Fig. 4C), we were able to relocate the stent to its appropriate position (Figs. 4C, 4D).
Case 3. A 42-year-old man with chronic renal failure underwent internal jugular venous catheterization at the bedside. During the procedure, the tip of the 8-F internal diameter venous introducer sheath fractured and migrated to the right atrium. Because the fragment moved vigorously in accordance with the patient's heartbeat, it was necessary to prevent its migration to the right ventricle or pulmonary circulation. Under fluoroscopic guidance, we inserted a 10-mm gooseneck snare through the right common femoral vein, successfully grasping the fragment and carefully pulling it back into the inferior vena cava (Fig. 5A). Because the fragment was very stiff and its outer diameter was 10-F, it had to be removed without folding. To this end, we used the modified coaxial technique illustrated in the ex-vivo study (Figs. 3B, 3C), inserting another 12-F vascular sheath (13 cm in length). The puncture site was more cranial to the previous one, used for insertion of the loop snare; the central lumen of the fragment was carefully located using an angiographic catheter and guidewire, and the dilator for the vascular sheath was then introduced over the guidewire (Fig. 5B). The entire retrieval system mirrored the one used in the ex-vivo experiment. After the dilator and the end of the sheath fragment were tightly engaged, the whole system was pulled back until the end of the fragment appeared at the femoral access site. It was grasped with forceps and successfully extracted after release of the loop snare and careful compression of the puncture site (Fig. 5C).
Case 6. A 51-year-old man with renal tuberculosis underwent periodic tube change under fluoroscopic guidance. The external part of the nephrostomy catheter was resected close to the point at which it entered the body, and during the procedure, the remaining catheter fragment was inadvertently dislodged, entering the nephrostomy tract. Several attempts to capture it caused its further migration into the pelvocalyceal system. We used a homemade loop snare and Amplatz gooseneck snare, also employing the 'in-situ loop snare' technique, as described by Savader et al., but because the fragment was tightly wedged against the wall, were unable to withdraw any part of it (Fig. 6A). During the various attempts, we managed to pass the guidewire through the central lumen of the catheter fragment, inserting the Amplatz loop snare over the guidewire and easily capturing the proximal tip of the catheter fragment coaxially (Fig. 6B). A dilator was introduced over the guidewire to eliminate the shoulder between it and the cut catheter end and to allow smooth extraction with minimal injury to the access route. The entire system was successfully extracted by simultaneously withdrawing the snare and dilator through the tract (Fig. 6C). The patient was discharged uneventfully after placement of another nephrostomy catheter.