Calcified in-stent restenosis: a rare cause of dilation failure requiring rotational atherectomy.

The acute results of repeated interventions for patients with in-stent restenosis (ISR) are largely satisfactory, although some patients may still have recurrences.1,2 In this anatomic scenario, lack of initial angiographic success is exceedingly rare.1,2 We report a patient with “undilatable” ISR that eventually required rotational atherectomy to achieve procedural success. Optical coherence tomography (OCT) and intravascular ultrasound (IVUS) unraveled the presence of severely calcified intrastent tissue, leading to “resistant” ISR. A 77-year-old man on hemodialysis was investigated for unstable angina. Coronary angiography revealed ISR of a bare metal stent that had been implanted in the right coronary artery 10 years before (Figure 1A). A saphenous vein graft to the left anterior descending coronary artery and a drugeluting stent implanted at the left main toward the proximal circumflex coronary artery showed good results. Initial coronary intervention on the right coronary artery was unsuccessful because of resistant ISR. After failure of conventional balloons, 2 different noncompliant balloons eventually ruptured (20 bar) at the lesion site. At a repeated procedure performed 1 week later, OCT imaging revealed severe and diffuse calcification of the intrastent tissue (Figure 1B, 1C, and 1D) with a minimal lumen area of 1.5 mm. Some neointimal ruptures were recognized (attributed to the previous treatment), but additional images of neoatherogenesis—as thin-cap fibroatheroma—were not present. IVUS (Figure 1E) also