Introduction
Percutaneous coronary intervention (PCI) has become the most commonly used invasive treatment for patients with coronary heart disease (CHD).1 Despite great advances in equipment technology, the presence of severe vessel tortuosity, extreme angulation of side-branch ostia, stent jail, or lack of control at the interface of chronic total occlusions (CTO) can result in procedural failure or complications.2 In the treatment of a CTO, for instance, studies suggest that the most common cause of failure was inability to pass the guidewire across the occlusion.3 In these situations, the ability to re-configure working tip angulations of