Utility of coronary orbital atherectomy with guide-extension system for distally located undilatable in-stent restenosis: A case report.

Orbital atherectomy (OA) may be effective in managing undilatable in-stent restenosis (ISR) despite off-label indications. We demonstrated that optical frequency domain imaging (OFDI)-guided OA, with a guide-extension system was effective even in distally located, undilatable ISR. However, OFDI revealed that inter-struts calcified neoatherosclerosis remained a challenging issue.