Efficacy of a Paclitaxel-Eluting Nitinol Stent on the Inhibition of Pseudointimal Hyperplasia in a Transjugular Intrahepatic Portosystemic Shunt: An Experimental Study in a Swine Model

PURPOSE: To evaluate the efficacy of a paclitaxel-eluting nitinol stent on the inhibition of pseudointimal hyperplasia in a transjugular intrahepatic portosystemic shunt. MATERIALS AND METHODS: Twelve pigs were used in this study. Two types of 10-mm diameter and 60-mm long nitinol stents were made for a transjugular intrahepatic portosystemic shunt by coating them with a polyurethane solution, with and without paclitaxel. Each transjugular intrahepatic portosystemic shunt was created successfully in the 12 swine with 7 paclitaxel-eluting stents and 5 polyurethane stents. Five swine in each group were followed-up for 14 days due to the death of 2 swine given the paclitaxel-eluting stents. The proliferation of the pseudointima was evaluated on both follow-up portograms and histopathology examinations. The mean maximum pseudointimal hyperplasia is expressed as the percentage of the stent radius. RESULTS: On the portograms, all the transjugular intrahepatic portosystemic shunts using the paclitaxel-eluting stents maintained patency despite there being a complete occlusion of the polyurethane stents in all the animals. The histopathology analysis revealed the mean maximum pseudointimal hyperplasia to be 25% and 76% in the paclitaxel-eluting and control stents, respectively. CONCLUSION: A transjugular intrahepatic portosystemic shunt with a paclitaxel-eluting nitinol stent appears to significantly inhibit the formation of pseudointimal hyperplasia.

Efficacy of a Dexamethasone-Eluting Nitinol Stent on the Inhibition of Pseudointimal Hyperplasia in a Transjugular Intrahepatic Portosystemic Shunt: An Experimental Study in a Swine Model

OBJECTIVE: We wanted to evaluate the feasibility and efficacy of using a dexamethasone (DM) -eluting nitinol stent to inhibit the pseudointimal hyperplasia following stent placement in the transjugular intrahepatic portosystemic shunt tract (TIPS) of a swine. MATERIALS AND METHODS: Fifteen stents were constructed using 0.15 mm-thick nitinol wire; they were 60 mm in length and 10 mm in diameter. The metallic stents were then classified into three types; type 1 and 2 was coated with the mixture of 12% and 20%, respectively, of DM solution and polyurethane (PU), while type 3 was a bare stent that was used for control study. In fifteen swine, each type of stent was implanted in the TIPS tract of 5 swine, and each animal was sacrificed 2 weeks after TIPS creation. The proliferation of the pseudointima was evaluated both on follow-up portogram and pathologic examination. RESULTS: One TIPS case, using the type 1 stent, and two TIPS cases, using the type 2 stent, maintained their luminal patency while the others were all occluded. On the histopathologic analysis, the mean of the maximum pseudointimal hyperplasia was expressed as the percentage of the stent radius that was patent, and these values were 51.2%, 50% and 76% for the type 1, 2, and 3 stents, respectively. CONCLUSION: The DM-eluting stent showed a tendency to reduce the development of pseudointimal hyperplasia in the TIPS tract of a swine model with induced-portal hypertension.