Intraluminal irradiation for TIPS stenosis: Preliminary results in a swinemodel

PURPOSE: To evaluate the ability of (32)phosphorus intraluminal irradiation to reduce pseudointimal hyperplasia in a transjugular intrahepatic portosy stemic shunt (TIPS). MATERIALS AND METHODS: TIPS were successfully placed in 11 swine with norma l portal pressures. Six animals received 15.2 Gy intraluminal irradiation t o the hepatic parenchyma and venous outflow tract at the time of TIPS place ment with use of a NA(32)P-filled balloon angioplasty catheter, Five contro l animals underwent TIPS and balloon angioplasty with saline. All animals w ere followed up for 28 days, at which time percutaneous portography was per formed, the animals were killed, and the tissue around the TIPS stent was p rocessed for histologic analysis. Maximum pseudointimal hyperplasia as a pe rcentage of estimated TIPS diameter was calculated for each animal. RESULTS: At the time of euthanasia, all five control TIPS and all but one i rradiated TIPS were occluded, Histologic analysis demonstrated considerable variability in the degree of pseudointimal hyperplasia within each TIPS an d between animals, No statistically significant difference was found in the maximum pseudointimal hyperplasia, measured as a percentage of stent radiu s, between control (80.2% +/- 17.4%) and irradiated animals (69.2% +/- 25.2 %). CONCLUSIONS: Irradiation of TIPS with 15.2 Gy P-32 delivered at the time of TIPS placement did not significantly improve TIPS patency or reduce the de gree of pseudointimal hyperplasia in swine with normal portal pressures.