Distal shower embolization during directional coronary atherectomy and stenting for diffuse stenosis of right coronary artery: current limitations of intravascular ultrasonography for evaluating fragile plaque.

A 74 year-old male with old anterior and inferior myocardial infarctions was treated with staged percutaneous coronary intervention. A chronic total occlusion of the middle segment of the left anterior descending branch was successfully stented during the first stage, and during the second stage, preprocedural intravascular ultrasonography (IVUS) revealed that the proximal segment of the right coronary artery was diffusely stenosed by mixed plaque. Directional coronary atherectomy under IVUS guidance was performed, but coronary slow flow appeared during the procedure. After successfully bailing out with intracoronary nicorandil, percutaneous thrombectomy and manual blood pumping, 2 coronary stents were implanted to fully cover the lesion. Quite contrary to expectation, the no-reflow phenomenon appeared just after post-dilatation and a repeat of the same maneuver could not completely recover coronary flow. Plaque fragility could not be predicted from the IVUS examination.