A 60 year-old man presented with a 2-day history of intermittent chest pain. Electrocardiogram showed an ST-segment elevation in lead aVR with a diffuse ST-segment depression in all precordial leads, which is suspicious for left main coronary artery disease. After loading of aspirin 300 mg and ticagrelor 180 mg, urgent coronary angiography (CAG) was performed via left snuffbox approach using 6 Fr radial sheath (Radifocus® Introducer II, Terumo Corporation, Tokyo, Japan) (Fig. 1A). CAG demonstrated the severe stenosis in the distal left main coronary artery (LMCA) that extended into proximal left anterior descending artery (LAD) (Fig. 1B, left). Therefore, intravascular ultrasound (IVUS) guided percutaneous coronary intervention (PCI) was planned. IVUS showed minimal lumen area of 2.3 mm² with plaque burden of 86.5%, a proximal and distal reference vessel diameter of 5.45 mm and 3.95 mm, respectively (Fig. 1C–E). IVUS image of diffuse fibroatheroma with large plaque burden led to direct stenting from LMCA to proximal LAD with a 3.5×28 mm everolimus-eluting stent (XIENCE Sierra®, Abbott Vascular, Santa Clara, CA, USA) at 16 atmospheres. Postdilation for proximal optimization technique (POT) was achieved with a 5.0×12 mm non-compliant balloon (NC Emerge™, Boston Scientific, Natick, MA, USA) at up to 18 atmospheres and repeated IVUS assessment demonstrated good strut apposition and minimal and maximal stent area of 8.0 mm² and 20.6 mm² (stent diameter of 4.9 and 5.4 mm), respectively (Fig. 1F–H). Final CAG showed good distal flow without residual stenosis (Fig. 1B, right). There was no bleeding complication at the sheath removal site with 3-hour hemostasis by compressive bandage method.