Association of Multimodal Intracoronary Imaging-Derived Plaque Morphology with the Pathophysiological Disease Patterns Assessed by the Quantitative Flow Ratio-Pullback Pressure Gradient

Abstract

Aims: The quantitative flow ratio (QFR)-derived pullback pressure gradient (PPG) characterizes the pathophysiological patterns of coronary atherosclerosis. This study investigated the plaque morphologies associated with these disease patterns.

Methods: This study used the institutional QFR-PPG database registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN000056097). Patients who underwent elective stenting with pre-procedural optical coherence tomography and near-infrared spectroscopy intravascular ultrasound were included. Offline QFR and QFR-PPG analyses were performed, and the lesions were stratified into tertiles.

Results: A total of 168 de novo lesions were analyzed in this study. The QFR tertiles were defined as severe (＜0.61), moderate (0.61–0.71), and mild (＞0.71); the QFR-PPG tertiles were defined as diffuse (＜0.66), intermediate (0.66–0.79), and focal (＞0.79). The Severe QFR tertiles exhibited a smaller minimum lumen area (MLA) and higher frequencies of thin-cap fibroatheroma (TCFA) and layered plaque. In contrast, across the QFR-PPG tertiles, MLA and TCFA frequencies were similar, whereas the diffuse group exhibited more layered plaques and larger calcium angles. The maximum lipid-core burden index did not vary across the QFR-PPG tertiles. A multivariable analysis identified MLA and TCFA as independent predictors of QFR, while layered plaque and calcium angle independently predicted QFR-PPG. However, the lipidic features were not independent predictors of QFR.

Conclusion: Multimodal intracoronary imaging demonstrated that QFR reflects luminal narrowing and the features of vulnerable plaques. Conversely, QFR-PPG reflects disease diffuseness, characterized by layered plaques and calcium burden rather than lipid-rich features.