PURPOSE: To evaluate the effect of bile on smooth muscle cell (SMC) proliferation in vitro and in vivo in a porcine transjugular intrahepatic portosystemic shunt (TIPS) model. MATERIALS AND METHODS: In vitro, SMCs explanted from porcine thoracic aorta were cultured with standard techniques. After initial pilot studies, they were subcultured in one of three groups: 1% porcine serum plus 1% bile, 10% porcine serum plus 1% bile, and 10% porcine serum. Cells were harvested at 3, 10, or 14 days, and DNA, protein, and disintegrations per minute (an indicator of proliferation) were measured. In vivo, TIPS creation was successful in 45 swine. All pigs were euthanized at 10-16 days. The proliferative response within the stent was histologically quantified and correlated for evidence of bile leak. RESULTS: In pilot studies, 2.5%-10.0% bile solutions caused 100% SMC mortality by 3 days. In the presence of 1% bile (with or without porcine serum), both DNA and protein production decreased significantly compared with that in porcine serum alone (P<0.05). In vivo, 13 of 45 specimens (29%) showed bile leak at gross or microscopic examination. SMC proliferation was less overall in animals with versus those without bile leak (difference not significant). CONCLUSION: These data suggest that the proliferative response in a TIPS is not primarily due to bile leak. Bile leak may promote thrombosis, but it appears to inhibit myointimal proliferation.

The objective of this study was to simplify the opacifying mixing process of the bone cement and contrast used for percutaneous vertebroplasty (PVP). We performed a biomechanical study of polymethyl methacrylate (PMMA) (CorinplastTM 3) using three different mixtures of PMMA, monomer, and contrast: group Ⅰ, 2:1; group Ⅱ, 3:2; group Ⅲ, 3:2:1 ratio of powder/monomer/iodinated contrast (Omnipaque). In vitro biomechanical testing of ultimate compressive strength was carried out in all samples. Following the conclusion of a proper bone cement mixture regimen drawn from the in vitro study, PVP was performed in 125 patients: 58 with cancer, 12 with hemangioma, and 54 with osteoporotic fracture. The ultimate compressive strength in group Ⅲ was decreased by 38% compared to groups Ⅱ and Ⅰ. Proper fluoroscopic visualization was achieved in all PVP procedures using this mixture. There were no major complications associated with injection of the cement mixture. Complete (CR) and partial response (PR) was obtained in 64% and 32.8%, respectively. No further vertebral collapse occurred during follow-up. The regimen using iodinated contrast for cement visualization during PVP provides a simple and convenient new method for mixing. Although the biomechanical strength is altered by the contrast medium added, it seems insignificant in clinical practice based on the authors' limited experience.

AIM To evaluate a new balloona2expandable stainless steel stent (Cordis stent) in a transjugular intrahepatic portosystemic shunt (TIPS) porcine model and compared with Wallstent.METHODS TIPS was performed in 26 normal domestic pigs weighing 20kg-30kg using a Cordis stent or Wallstent (13 pigs in each stent). All pigs were sacrificed at the 14th day after TIPS. The stent deployment delivery system, stent patency, and stent recoil after placement were evaluated.Proliferative response in representative histological sections from the center, hepatic and portal regions of the two stent designs were quantified.RESULTS The shunt was widely patent in 4 pigs in the Cordis stent group (4/12, premature dead in 1 pig), and in 5 pigs in the Wallstent group (5/13). All remaining stents of both designs were occluded or stenotic. The mean quantified proliferation including thickness of the proliferation and the ratio of proliferation: total area in three assayed regions in Cordis stent and Wallstent was 2.18mm2 2:00mm, and 59.18mm2. 51.66mm2, respectively (P<0.05). The delivery system and mechanical properties of the Cordis stent fuctioned well.CONCLUSION The new Cordis stent is appropriate for TIPS procedure.