Intracoronary Imaging of Coronary Atherosclerotic Plaque: From Assessment of Pathophysiological Mechanisms to Therapeutic Implication

Abstract

Atherosclerotic cardiovascular disease is the leading cause of morbidity and mortality worldwide. Several cardiovascular risk factors are implicated in atherosclerotic plaque promotion and progression and are responsible for the clinical manifestations of coronary artery disease (CAD), ranging from chronic to acute coronary syndromes and sudden coronary death. The advent of intravascular imaging (IVI), including intravascular ultrasound, optical coherence tomography and near-infrared diffuse reflectance spectroscopy has significantly improved the comprehension of CAD pathophysiology and has strengthened the prognostic relevance of coronary plaque morphology assessment. Indeed, several atherosclerotic plaque phenotype and mechanisms of plaque destabilization have been recognized with different natural history and prognosis. Finally, IVI demonstrated benefits of secondary prevention therapies, such as lipid-lowering and anti-inflammatory agents. The purpose of this review is to shed light on the principles and properties of available IVI modalities along with their prognostic significance.

State-of-art review: intravascular imaging in percutaneous coronary interventions

“…Stent expansion is the process of deploying the stent to achieve a desired vessel diameter based on reference vessel size, ensuring adequate luminal gain and restoration of blood flow, and decreasing risk of in-stent restenosis [58][59][60][61] . Generally, moderate stent under expansion refers to a stent-to-artery ratio less than 90% while (Adapted from Gurgoglione et al [53] under Creative Commons License). OCT: optical coherence tomography; IVUS: intravascular ultrasound.…”

“…OCT offers superior resolution for detecting and characterizing edge dissections, including their length, depth, and location in relation to the stent struts. Due to the high-resolution images produced by OCT, this (Adapted from Gurgoglione et al [53] under Creative Commons License). OCT: optical coherence tomography.…”

“…A, Example of a ruptured plaque, characterized by the evidence of a cavity with a clear discontinuity of the fibrous cap (white arrow); B, Example of a definite eroded plaque, characterized by a luminal thrombus (white arrow) overlying a plaque without evidence of fibrous cap disruption; C, Example of a calcified nodule at the white arrow depicted as single of multiple regions of calcium that protrude into the lumen with fibrous cap disruption. (Adapted from Gurgoglione et al[53] under Creative Commons License). OCT: optical coherence tomography.…”

“…A, Example of calcified plaque on IVUS, depicted as a bright circumferential structure (white arrow) with deeper shadowing (white star); B, Example of predominantly lipid-laden plaque by IVUS, depicted with less echogenicity than the surrounding hyperechoic adventitia, with a spotty calcification demarcated by the white arrow as a focal hyperechoic signal; C, Example of calcific plaque by OCT with white arrow depicting low-backscattering structure compared to surrounding adventitia with sharply delineated borders; D, Example of thin-cap lipid-laden plaque on OCT, depicted as a low-density structure with diffuse borders covered by a thin fibrous cap with the white arrow identifying signal-rich distinct or confluent punctate regions that exceed intensity of background speckle noise, representing macrophages. (Adapted from Gurgoglione et al[53] under Creative Commons License). OCT: optical coherence tomography; IVUS: intravascular ultrasound.…”

Coronary Spasm Testing with Acetylcholine: A Powerful Tool for a Personalized Therapy of Coronary Vasomotor Disorders

“…Histopathological studies found pronounced adventitial pro-inflammatory milieu at the site of coronary vasospasm, with increased levels of eosinophils and neutrophils cells [ 47 , 48 ]. Intracoronary imaging tools, traditionally used to characterize coronary plaque phenotype and to guide percutaneous coronary interventions (PCI) [ 49 ], have contributed to understand CAS pathology: studies with intravascular ultrasound and optical coherence tomography revealed diffuse intimal thickening [ 50 ], as well as abundant macrophages and an exaggerated expression of vasa vasorum at spastic sites [ 51 ]. Importantly, by leveraging 18-fluorodeoxyglucose positron emission tomography/computed tomography, Ohyama et al found a close link between the expansion of perivascular and pericoronary adipose tissue and the susceptibility to CVD [ 52 ].…”