LAUSR

A 64-year-old Japanese man with chronic kidney disease on hemodialysis due to diabetic nephropathy underwent a percutaneous coronary intervention due to worsening of effort angina pectoris. We deployed three drug-eluting stents (3.5 × 38, 3.5 × 32, and 3.0 × 20 mm; Promus Premier, Boston Scientic, Natick, Massachusetts, USA) in the right coronary artery (RCA) with a sufficient minimal cross-sectional stent area (>4.0 mm) by using intravascular ultrasound. Three years and four months later, the patient was admitted to our hospital because of acute coronary syndrome. Coronary angiography revealed in-stent restenosis (ISR) of the lesion in the RCA (Fig. 1a). We used an enhanced stent visualization (ESV) system (ClearStent Live system; Siemens Healthcare, Munich, Germany) to check the stent formation. The stent struts were completely fractured with a gap in the stent body (Fig. 1b). In addition, two-dimensional optical coherence tomography (OCT) clearly revealed a distorted stent at the fracture site and protrusion of struts into the lumen with thrombus (Fig. 1c and d). Therefore, the main reason for the recurrent ischemic event was thrombosis caused by the fractured stent. Although three-dimensional OCT is also a useful tool to detect the stent fracture [1,2], it is difficult to construct the stent morphology in the chronic stage of stent implantation by this imaging modality, because many stent struts might be covered and not detected. On the other hand, the ESV system can determine the stent morphology readily and quickly. Therefore, the combination of an ESV system and two-dimensional OCT was a useful tool to clarify the mechanism of ISR.