Percutaneous coronary intervention without use of guiding catheters for extreme downsizing: the Emperor's new clothes technique.

A 72-year-old male with effort angina pectoris and old myocardial infarction underwent percutaneous coronary intervention (PCI). A 4 Fr sheath was inserted in the radial artery. After diagnostic angiography, a guidewire was inserted from the diagnostic catheter. The diagnostic catheter is removed, and the distal tip of the guidewire remains in the coronary artery. Intravascular ultrasound (IVUS) could be performed via the 4 Fr sheath without guiding catheters. IVUS-guide PCI was successfully performed with 4 Fr sheath, although IVUS requires at least a 5 Fr or larger system. This technique is called "The Emperor's New Clothes Technique" because PCI is performed as if an invisible guiding catheter was being used.