Optical Coherence Tomography: Current Applications for the Assessment of Coronary Artery Disease and Guidance of Percutaneous Coronary Interventions

Abstract

Introduction Coronary angiography (CAG) is the standard modality for assessment of coronary stenoses and intraprocedural guidance of percutaneous coronary interventions (PCI). However, the limitations of CAG are well recognized. Intracoronary imaging (ICI) can potentially overcome these limitations. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are the main ICI techniques utilized in clinical practice. Aim This narrative literature review addresses the current clinical applications of OCT in relation to IVUS and CAG in patients with coronary artery disease (CAD). Items reviewed are: technical implications of OCT and IVUS, lesion characterization and decision-making, stent optimization criteria, post-stenting results, safety in terms of procedural complications, clinical outcomes, and indications. Main Findings OCT is able to reveal more detail than IVUS due to its higher resolution. However, this higher resolution comes at the cost of a lower penetration depth. Pre-stenting OCT results in procedural change in more than 50% of the cases in terms of stent length and diameter. Post-stenting OCT resulting in stent optimization is reported in at least 27% of the cases. Malapposition and under-expansion are treated with post-dilatations, while edge dissections are treated with additional stent placement. Stent expansion, stent apposition, distal stent edge dissections, and reference lumen areas seem to be the most important stent optimization criteria for both decision-making and for reducing the risk of adverse events during follow-up. Both OCT and IVUS are superior in terms of post-stenting results compared with CAG alone. However, there is no consensus about whether OCT guidance results in better stent expansion than IVUS guidance. OCT, IVUS, and CAG are safe procedures with few reported procedural complications. In general, OCT guidance seems to contribute to favorable clinical outcomes compared with CAG guidance only. However, OCT guidance results in similar clinical outcomes as with IVUS guidance. OCT could be considered for lumen assessment and stent-related morphology in more complex cases in which CAG interpretation remains uncertain. Since OCT and IVUS have distinct characteristics, these techniques are complementary and should be considered carefully for each patient case based on the benefits and limitations of both techniques. Electronic supplementary material The online version of this article (10.1007/s40119-020-00185-4) contains supplementary material, which is available to authorized users.

Microvascular and Prognostic Effect in Lesions With Different Stent Expansion During Primary PCI for STEMI: Insights From Coronary Physiology and Intravascular Ultrasound

“…Meanwhile, when the no-reflow occurred, an aggressive dilation strategy should not be taken. Optimal stent expansion gained by postdilation, which is related to a better prognosis, has been confirmed by multiple studies and included in the PCI recommendation consensus (18)(19)(20)(21). However, overexpansion or oversize of stent caused by excessive postdilation has been increasing recently, but it has been less studied.…”

Ten things to know about ten imaging studies: A preventive cardiology perspective (“ASPC top ten imaging”)

“…While OCT may provide better image resolution of the coronary arteries, IVUS has greater imaging penetration than OCT, where large lipid-rich plaques may impair the ability to image the vessel border with OCT. [136] OCT requires contrast (often iodine-based), [137] which increases the risk of contrast induced nephropathy. Alternative OCT contrasts such as dextran may help avoid acute kidney injury.…”

“…Alternative OCT contrasts such as dextran may help avoid acute kidney injury. [138] Contrast induced nephropathy [136] is a poor prognostic factor that often delays hospital discharge and increases costs. [139] In short, OCT may be superior to IVUS in assessing the cause of stent failure, calcific coronary disease, and MINOCA.…”

OCT Findings in MINOCA

“…Its higher resolution undoubtedly can confirm findings such as plaque erosion or calcified nodule which may cause AMI and usually are not visible on both conventional angiography and IVUS. Howbeit, it should be emphasized that OCT also has several drawbacks [37]. First, its greater resolution as compared to IVUS comes with a lower penetration depth.…”

“…An OCT study including 23 patients found that those with Takotsubo cardiomyopathy have high plaque vulnerability [42]. Howbeit, it should be emphasized that OCT also has several drawbacks [37]. First, its greater resolution as compared to IVUS comes with a lower penetration depth.…”