Stent underexpansion is associated with restenosis and subacute stent thrombosis. Construction of the perfect implant, with stent struts closely in contact with the internal walls of the arteries and a symmetric expansion, is difficult to achieve due to the heterogeneity of atherosclerotic plaques. Accurate judgement of the expansion of coronary stents by standard coronary angiography is limited to the radiopaque contour of the stent, with some amelioration due to signal enhancement (boost). Intravascular ultrasound more accurately detects inadequate stent expansion than coronary angiography. The current standard of care in stent implantation with high-pressure deployment was introduced thanks to intravascular ultrasound studies. However, attempts to obtain perfect strut apposition at any cost may result in additional vessel damage. Optical coherence tomography, which has an axial resolution of 15 μm, is able to detect subtle details that, until now, have not been available. The figure illustrates a rare case in which the use of high-pressure dilation for stent optimization resulted in media rupture with early positive remodeling and aneurysm formation, as detected by serial optical coherence tomographic examination.

Vasile Sirbu, MD, and Giulio Guagliumi, MD, are with the Cardiovascular Department at the Ospedali Riuniti di Bergamo in Bergamo, Italy.