Severely Circumferentially Calcified Neointima as a New Cause of Undilatable In-Stent Restenosis.

A 74-year old man presented recurrent angina pectoris due to in-stent restenosis (ISR) with severely calcified neointima. In-stent neoatherosclerosis (NA) is associated with late stent failure, and NA with calcified neointima occurs in some cases. Because the presence of neointimal calcification could lead to underexpansion of newly implanted stent for ISR, a scoring balloon was selected for predilatation to obtain maximum extrusion of the neointimal plaque and subsequently, an everolimus-eluting stent was implanted. However, moderate stenosis remained on coronary angiography, and optical coherence tomography (OCT) revealed underexpansion of the newly implanted stent because an attempt at balloon dilatation of neointimal calcification failed. Although OCT can clearly discriminate stent struts from neointimal calcification, we did not perform OCT assessment between scoring balloon and stenting. It is highly recommended to confirm whether the lesion is adequately treated by balloon angioplasty before stenting in cases with calcified ISR.