Detailed Characterization of Vulnerable Plaque Morphology by High-Resolution Intravascular Ultrasound

Two cases of ST-segment elevation myocardial infarction (STEMI) are presented to highlight the different diagnostic performance between optical coherence tomography (OCT) and high-resolution intravascular ultrasound (HR-IVUS).

Case 1: A 56-year-old man presented with an anterior STEMI. Coronary angiography was performed and severe stenosis was identified in the left anterior descending artery. After aspiration thrombectomy, OCT (Dragonfly^TM, Abbott Vascular, Santa Clara, CA, USA) and HR-IVUS (AltaView^TM, Terumo, Tokyo, Japan) were performed (Figure, Supplementary Movie 1). OCT demonstrated luminal narrowing with a mixed thrombus; disruption of the fibrous cap was not clearly visible. However, HR-IVUS revealed a large intraplaque cavity with fibrous cap disruption, consistent with a plaque rupture.

Figure.

Cross-sectional images. (A–F) Optical coherence tomography and (A’–F’) high-resolution intravascular ultrasound. *Intraplaque cavity.

Case 2: A 63-year-old man presented with an inferior STEMI. Coronary angiography revealed total occlusion of the right coronary artery. After aspiration thrombectomy, OCT and HR-IVUS were performed (Figure, Supplementary Movie 2). OCT demonstrated luminal narrowing with an eccentric low-intensity plaque and an intact thick fibrous cap. However, HR-IVUS indicated a large intraplaque cavity, consistent with plaque rupture.

OCT has been the gold standard for diagnosing plaque rupture, but HR-IVUS has evolved as next-generation IVUS with higher image resolution than conventional IVUS, showing high sensitivity for identifying OCT-derived plaque rupture.¹ The plaque rupture cases presented here were well identified by HR-IVUS but not OCT, suggesting that OCT cannot always give a definitive diagnosis of plaque rupture. In OCT, a fresh thrombus or thick fibrous cap may result in blind spots behind them, making it difficult to evaluate plaque morphology; this does not occur with HR-IVUS. Both imaging techniques have disadvantages that can be overcome by a hybrid IVUS/OCT device by complementing each other.

Disclosures

T.A. is a member of Circulation Journal’ Editorial Team.

Supplementary Files

Supplementary Movie 1. Case 1: OCT and HR-IVUS.

Supplementary Movie 2. Case 2: OCT and HR-IVUS.

Please find supplementary file(s);

http://dx.doi.org/10.1253/circj.CJ-20-0355

Reference

• 1.   Ohashi H, Ando H, Takashima H, Waseda K, Shimoda M, Fujimoto M, et al. diagnostic performance of high-resolution intravascular ultrasound for the detection of plaque rupture in patients with acute coronary syndrome. Circ J 2019; 83: 2505–2511.