Perspectives on Imaging the Left Main Coronary Artery Using Intravascular Ultrasound and Optical Coherence Tomography

Harry C. Lowe

Percutaneous coronary intervention (PCI) for significant left main coronary artery (LMCA) stenosis is increasingly being viewed as a viable alternative to coronary artery bypass grafting (CABG) (1). This is leading to an expectation of increasing numbers of such procedures with a consequent focus on both the ability to image lesion severity and assess more accurately the results of PCI. While there have been advances in physiological assessment of left main severity using fractional flow reserve (FFR) and in non-invasive assessment of the left main using coronary computerized tomography CT (2), imaging of the LMCA using intravascular ultrasound (IVUS) and more recently optical coherence tomography (OCT) has the specific advantage of being able to provide very detailed anatomical information both pre- and post-PCI, such that it is timely to review briefly the current status of these two imaging technologies in the context of LMCA intervention. This is presented specifically contrasting the use of these technologies both in pre-PCI lesion severity assessment, and peri-PCI procedural evaluation. Not discussed here is the separate issue of longer-term surveillance of asymptomatic patients having undergone LMCA stenting, which may appropriately be performed non-invasively using coronary CT, reviewed in detail elsewhere (2).