Optical coherence tomography-verified morphological correlates of high-intensity coronary plaques on non-contrast T1-weighted magnetic resonance imaging in patients with stable coronary artery disease

Coronary high-intensity plaques (HIPs) with a high plaque-to-myocardial signal intensity ratio (PMR) on non-contrast T1-weighted imaging in patients with stable coronary artery disease (CAD) are associated with future coronary events. To characterize the morphological substrate of HIP, we performed a correlative optical coherence tomography (OCT) study.

We examined 137 lesions in 105 patients with stable angina pectoris or silent myocardial ischaemia scheduled for percutaneous coronary intervention (PCI) using a 3 T magnetic resonance scanner. Pre-interventional OCT was performed for PCI target lesions. HIP was defined as PMR ≥ 1.4. Of the 137 lesions, 34% were HIP and 66% were non-HIP. The prevalence of lipid-rich plaque (96% vs. 70%, P < 0.001), macrophage accumulation (65% vs. 46%, P = 0.046), cholesterol crystals (46% vs. 22%, P = 0.006), and healed plaque rupture (multiple layers of different optical densities overlaying a large lipid accumulation, 72% vs. 18%, P < 0.001) was significantly higher in the HIP group than the non-HIP group; no significant differences were observed for the presence of thin cap fibroatheroma, intracoronary thrombus, and plaque rupture between the two groups. Multivariable stepwise logistic regression analysis showed that HIP was significantly associated with the presence of healed plaque rupture [odds ratio (OR) 9.32; 95% confidence interval (95% CI) 4.05–22.71; P < 0.001] and lipid-rich plaque (OR 4.38; 95% CI 1.08–29.77; P = 0.038).

The significant association between HIP- and OCT-derived healed plaque rupture and large lipid core provides new insights into the characteristics of high-risk plaques, even in clinically stable CAD.