Vascular brachytherpy known to be an effective method in the prevention of restenosis following percutaneous coronary intervention (PCI). In this study we observed the effects of a radioisotope-loaded stent in a porcine model.

Holmium-166 ((166)Ho) was loaded onto the stent surface using impregnated polyurethane, and placed the stents into 7 porcine coronary arteries. Four weeks after stent overdilation injury, histopathological examination was performed.

The absorbed dose of (166)Ho to the coronary artery, from the 158.5±140.9 microCi (166)Ho stent, was about 141 Gy at a depth of 0.5 mm, which was calculated by Monte Carlo EGS 4 Code. The mean external, and internal elastic lamina areas, the luminal and neointimal areas and the histopathological area stenosis in the 7 porcine coronary arteries were 7.6±2.8 mm², 4.7±1.6 mm², 2.4±1.4 mm², 2.3±1.6 mm² and 49.4±24.9%, respectively. The histopathological findings revealed remarkable inflammatory reactions and thrombosis in two of the porcine coronary arteries.

(166)Ho radioactive loaded stents, using impregnated polyurethane, may inhibit neointimal hyperplasia, but the problems of stent thrombosis and inflammation should be solved.