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.
Focal in stent stenosis was found in 12 patients, diffuse in stent stenosis in 7, and new lesion in 12 patients. Both studies are influenced by the use of an additional stent on top of the original stent. The most likely mechanism is lack of re-endothelialization, and therefore prolonged antiplatelet therapy is needed. Edge restenosis can be addressed by adequate coverage with the source, and reoccurrence by optimizing the dose. All Rights Reserved.