Disappearance of intima over the stent and ulcer formation after intracoronary radiation for in-stent restenosis.

Little is known about the alterations of the vascular surface after radiation therapy for in-stent restenosis in humans, even though animal experiments suggest that delayed healing of the neointima is a cause of late thrombosis. Coronary angioscopy, together with coronary angiography, was performed at 3 months follow-up of 7 patients with in-stent restenosis who underwent beta-radiation therapy. Minimal lesion diameter (MLD) of the lesion increased from 1.00+/-0.30 mm (immediately before) to 2.44+/-0.39 mm (immediately after) and the MLD was well maintained 3 months later (2.34+/-0.62 mm) without any cases of restenosis. In 5 patients, the intima was so thin that some stent struts could be seen through it on angioscopy and in 2 of those, the intima over the stent had disappeared and 1 patient showed ulceration of the vascular wall beneath the stent. After intracoronary radiation therapy, the intima can become so thin that some stent struts are exposed to the lumen, which may be related to the occurrence of late thrombosis. Accordingly, patients who are treated with intracoronary radiation therapy may need long-term antiplatelet therapy.