Therefore, it is likely that a device will be approved in the US by year end. PAGE TOP Radioactive stents Radioactive stents are of great interest due to the vision of the stent itself preventing abnormal remodeling of the vessel and the radiation preventing intimal hyperplasia, making this perhaps the perfect tool to prevent restenosis. However, the results in the pilot studies of randomized trials have been disappointing. PAGE TOP Major issues to be addressed Edge restenosis, which is largely increased intimal hyperplasia, may explain why radioactive stents have failed to fulfill their promise thus far. Another factor leading to the failure of radiation to prevent restenosis could be geographic miss, meaning that the radioactive wire is not placed to bridge the damaged area that the balloon has injured by at least 5 mm.
Geographical miss can lead to a fairly highly rate of restenosis in the missed segment.
Dosing may be another issue. The studies using 12 Gy or lower had minimal effect. Low doses may not only lack benefit, but have a detrimental effect. Dose-response relationships and the minimally effective dose are becoming increasingly understood. Total occlusion is a recently noted problem in radiation.