Questionable IVUS Image in Coronary Artery

IVUS in Acute Coronary Syndrome: Can We Trust What We See?

Mira Elwood in Health & Wellness June 2025 • 4 min read.

"Experts debate the reliability of intravascular ultrasound in characterizing attenuated plaque during acute coronary events."

A recent publication by Hibi et al. has ignited discussions within the cardiology community regarding the efficacy of distal protection (DP) devices in treating acute coronary syndrome (ACS) when attenuated plaque (characterized by a longitudinal length of ≥5 mm) is identified via intravascular ultrasound (IVUS) imaging. While earlier studies have not consistently demonstrated the long-term benefits of DP, this study suggests promising outcomes, particularly in reducing slow flow and no-reflow phenomena, potentially mitigating fatal arrhythmias and cardiogenic shock during the acute phase.

However, the observation that creatine kinase-MB levels post-revascularization did not significantly differ between the study groups raises questions. Critics argue that this lack of difference introduces a degree of uncertainty, challenging the unequivocal endorsement of DP's effectiveness in such scenarios.

Adding fuel to the fire, a letter to the editor highlights concerns regarding the study's external validity, questioning the widespread applicability of DP in contemporary percutaneous coronary interventions. The authors point to potential selection biases, extended enrollment periods, and the possibility that pre-IVUS procedures, like aspiration or balloon angioplasty, might alter plaque morphology, further complicating the interpretation of IVUS findings.

Decoding Attenuated Plaque: Thrombus or Truth?

Questionable IVUS Image in Coronary Artery

One of the key criticisms revolves around the interpretation of IVUS images, specifically concerning attenuated plaque. It's suggested that the presence of thrombus, which is known to interfere with IVUS signals, could potentially mask the true nature of the plaque morphology. In essence, a high-attenuation image might not solely represent plaque but could also indicate the presence of thrombus or a combination of both.

This distinction is crucial because the treatment strategies for thrombus and plaque differ significantly. Misinterpreting a thrombus-laden lesion as solely plaque could lead to suboptimal treatment decisions and potentially adverse outcomes for patients.

Impact on IVUS Signal: Both thrombus and plaque affect how ultrasound waves bounce back, but thrombus can create misleading high-attenuation signals.
Potential for Misdiagnosis: The risk of mistaking thrombus for plaque raises concerns about the accuracy of IVUS in guiding interventions.
Altered Treatment Strategies: When thrombus is present, additional steps to address thrombus resolution may be needed to optimize outcomes.

Adding to the complexity, the letter also questions the blinding of the primary endpoint analysis. The fact that the core laboratory is aware of whether a DP device was used during the procedure could introduce bias into the evaluation, potentially influencing the interpretation of results. This is particularly relevant given the subjective nature of assessing plaque characteristics on IVUS images.

Future Directions: Re-evaluating IVUS?

Ultimately, the authors advocate for a more comprehensive approach, suggesting the integration of additional imaging modalities, such as magnetic resonance imaging (MRI), to gain a more complete understanding of the long-term impact of DP use. By combining different imaging techniques, clinicians may be able to overcome the limitations of individual modalities and achieve a more accurate assessment of plaque characteristics and treatment outcomes in patients with ACS.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.jcin.2018.09.031, Alternate LINK

Title: Using Intravascular Ultrasound In Patients With Acute Coronary Syndrome

Subject: Cardiology and Cardiovascular Medicine

Journal: JACC: Cardiovascular Interventions

Publisher: Elsevier BV

Authors: Kazuhiro Dan, Ron Waksman, Hector M. Garcia-Garcia

Published: 2018-12-01

Everything You Need To Know

What exactly is intravascular ultrasound, and why is there discussion about how reliable it is?

Intravascular ultrasound or IVUS is an imaging technique used during percutaneous coronary intervention (PCI) to visualize the inside of coronary arteries. It employs ultrasound waves to create detailed images of the arterial walls, helping cardiologists assess the presence and characteristics of plaque. However, its reliability in characterizing attenuated plaque, especially during acute coronary syndrome (ACS) events, is debated due to potential interference from thrombus and variability in image interpretation.

What are distal protection devices and how might they help with treating acute coronary syndrome?

Distal protection (DP) devices are used during PCI to capture debris, such as thrombus or plaque particles, released during the procedure, preventing them from traveling downstream and causing blockages in smaller vessels. The study suggests that distal protection might be beneficial in reducing slow flow and no-reflow phenomena when attenuated plaque is identified via IVUS during ACS. This is significant because slow or no-reflow can lead to complications like arrhythmias and cardiogenic shock. The use of distal protection however is still being debated.

What is meant by 'attenuated plaque' and why is it so important to accurately identify it?

Attenuated plaque, as visualized by IVUS, refers to plaque that appears to have a weakened or reduced signal on the ultrasound image. The issue is whether the appearance of attenuated plaque is solely due to the plaque composition or if it is influenced by the presence of thrombus. This distinction is crucial because thrombus and plaque require different treatment strategies, and misinterpreting one for the other can lead to suboptimal outcomes.

What does it mean that creatine kinase-MB levels didn't change much in the study, and why does it matter?

Creatine kinase-MB (CK-MB) is an enzyme released into the bloodstream when heart muscle is damaged. Measuring CK-MB levels after revascularization helps assess the extent of myocardial injury. The fact that the levels did not significantly differ between the study groups raises questions about the benefits of distal protection (DP). Critics argue that this lack of difference introduces a degree of uncertainty, challenging the unequivocal endorsement of DP's effectiveness in such scenarios.

Besides IVUS, what other imaging methods, like MRI, could help get a clearer picture of what's happening in the arteries?

Magnetic resonance imaging or MRI could provide complementary information about plaque composition and characteristics that IVUS alone cannot. It offers better tissue characterization and can help differentiate between different types of plaque, thrombus, and other tissue components. By integrating MRI with IVUS, clinicians could potentially achieve a more accurate assessment of plaque and treatment outcomes in patients with ACS.