Optical Coherence Tomography for Online Guidance of Complex Coronary Interventions.

Decision making on lesion preparation and stent/scaffold optimization are cornerstones of patient outcome. Intravascular imaging recently emerged as a critical modality to achieve better results of stent/scaffold implantation and superior clinical outcomes compared with coronary angiography alone. Optical coherence tomography (OCT), a light-based intravascular imaging modality with high frame rate in acquisition and very high speed pullback, can interrogate the target vessel in a couple of seconds, and immediately display a pristine longitudinal lumen contour with automatic detection of lesion severity, site and lumen/stent areas. Further, OCT provides pivotal information on sites of calcium, with accurate measurements of the minimum distance from the lumen, a major determinant of stent/scaffold underexpansion, malapposition and eccentricity. Finally, to guide the PCI procedure using OCT without operator misjudgment, a real-time point-to-point correspondence between angiographic and OCT images has been recently created. Co-registration of OCT with angiography with direct tableside control of acquisition and analysis enables the operator to plan and map optimal stent/scaffold implantation. To prove the clinical relevance of OCT-guided PCI, simple, standardized interventional planning, including pre- and postprocedural automatic lumen detection metrics, has to be translated into effective treatment flow algorithms. A similar OCT algorithm is being tested in the ongoing prospective, randomized, multicenter ILUMIEN III study, to demonstrate that OCT-guided stent placement is superior to angiography-guided and non-inferior to IVUS-guided stent implantation. (Circ J 2016; 80: 2063-2072).