Evaluation of coronary plaques and atherosclerosis using optical coherence tomography

ABSTRACT

Introduction: Coronary angiography (CAG) is the standard modality for assessing coronary stenosis; however, it has limitations in assessing coronary plaque morphology. Optical coherence tomography (OCT) is a high-resolution (10–20 μm) light-based intravascular imaging technique that can identify more detailed coronary plaque morphology compared to other intravascular imaging modalities. OCT is remarkable for characterizing fibrous, fibrocalcific, and lipid-rich plaques. The capabilities of OCT are well suited for discriminating three types of unstable plaque morphologies underlying coronary thrombosis, such as plaque rupture, erosion, and calcified nodules. The high resolution of OCT makes it possible to identify important features of vulnerable plaques, such as thin-cap (<65 μm thick) fibroatheroma, macrophages, vasa vasorum, and cholesterol crystals.

Areas covered: This review summarizes the clinical impact of OCT and its efficacy in identifying plaque components and morphological features associated with plaque vulnerability.

Expertopinion: The unique properties of OCT as a tool for investigating high-risk lesions have greatly contributed to a better understanding of plaque vulnerability. Consequently, OCT has led to significant changes in medical treatment and percutaneous coronary intervention strategies for acute coronary syndrome. Further development and investigation of OCT are necessary to better predict and manage acute coronary events in the future.

KEYWORDS:

• Acute coronary syndrome
• calcified nodule
• erosion
• optical coherence tomography
• plaque rupture
• thin–cap fibroatheroma
• vulnerable plaque

Article highlights

• Optical coherence tomography (OCT) is an innovative catheter-based imaging technique for visualizing coronary vessel microstructures with an extraordinarily high resolution.

• OCT enables detailed visualization of atheromatous plaques, thus differentiating between early stage and advanced-stage coronary lesions, with good agreement with histology and high reproducibility.

• OCT overcomes the limitations of coronary angiography and intravascular ultrasound (IVUS), including assessment of the extent and thickness of calcification, and identification of thrombus.

• OCT allows cardiologists to consider the pathological mechanisms of coronary atherosclerosis and appropriate medical and interventional treatments for vulnerable patients.

• Many OCT studies have led to significant changes in medical treatment and percutaneous coronary intervention (PCI) strategies in acute coronary syndrome (ACS).

• Although current guidelines for the management of both STEMI and NSTE-ACS generally recommend early PCI, other options (aggressive medical treatment and/or use of atherectomy devices) without stenting may be effective for patients with ACS due to erosion or calcified nodules.

• Further development and investigation of OCT are necessary to better predict and manage acute coronary events in the future.

Declaration of interest

T Akasaka has received speaker honoraria and research support from Abbot Vascular Inc. and Terumo Corporation. All other authors have no relationships relevant to the contents of this paper to disclose.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.