Abstract Background The association between morphological plaque features and pathophysiological disease patterns remains poorly understood. Purpose This study aimed to investigate the relevance of high-risk coronary plaque characteristics, as identified by optical coherence tomography (OCT) and near-infrared spectroscopic intravascular ultrasound (NIRS-IVUS), in relation to varying degrees of pathophysiological coronary atherosclerotic disease patterns, assessed using the quantitative flow ratio (QFR)-derived pullback pressure gradient (PPG). Methods We evaluated 158 de novo coronary lesions in 158 patients with chronic coronary syndrome who underwent OCT, NIRS-IVUS, and QFR-PPG assessments. Lesions were categorized into tertiles based on QFR-PPG values. OCT findings included minimal lumen area (MLA), plaque rupture, thin-cap fibroatheroma (TCFA), layered plaque, and calcification. OCT-derived TCFA was defined as a lipid-rich plaque (lipid arc ≥ 90 degrees) with a fibrous cap thickness 80 µm. NIRS-IVUS findings included MLA, maximum plaque burden, remodeling index, echo attenuation, and maximum lipid core burden index over a 4-mm segment in the culprit lesion (max LCBI4mm). IVUS-derived TCFA was identified by the presence of echolucent zones and/or ultrasound attenuation in areas of positive remodeling. Clinical demographics and OCT and NIRS-IVUS findings were compared across the QFR-PPG tertiles. Results In this cohort, the median QFR-PPG value was 0.74 (interquartile range IQR: 0.62–0.82). The median age was 69.5 years (IQR: 62.0–74.8), and 79.7% (126/158) of patients were male. QFR-PPG tertiles were defined as follows: 1st tertile (Diffuse group): QFR-PPG 0.66, 2nd tertile (Intermediate group): 0.66 ≤ QFR-PPG ≤ 0.80, 3rd tertile (Focal group): QFR-PPG 0.80. Clinical demographics showed no significant differences across tertiles. On OCT, MLA, lipid arc, fibrous cap thickness, and the prevalence of plaque rupture and TCFAOCT did not vary with the QFR-PPG index. However, the prevalence of layered plaque demonstrated graded differences across tertiles: 64.8% in the Diffuse group, 50.9% in the Intermediate group, and 37.3% in the Focal group (P for trend 0.01). Similarly, calcium angle showed graded differences: 103 degrees (IQR: 0–218) in the Diffuse group, 82 degrees (IQR: 0–188) in the Intermediate group, and 38 degrees (IQR: 0–98) in the Focal group (P for trend 0.01). On NIRS-IVUS, maximum plaque burden, prevalence of IVUS-derived TCFA, and maxLCBI4mm showed no differences across tertiles. Multivariable linear regression analysis indicated that OCT-derived layered plaque and calcium angle were independently associated with the QFR-PPG index. Conclusion Multimodal intracoronary imaging revealed that pathophysiological atherosclerotic patterns were associated with the presence of layered plaques and calcium burden, rather than lipid-related unstable plaque features.
Usui et al. (Sat,) studied this question.