Functional and morphological characterization of coronary atherosclerosis

Background The interplay between coronary artery hemodynamics and atherosclerotic plaque is not fully understood. The Pullback Pressure Gradient (PPG), a novel physiological metric, categorizes coronary artery disease (CAD) into focal or diffuse patterns based on coronary physiology. Objectives This study investigates the association between the PPG and coronary atherosclerosis, as characterized by intravascular ultrasound (IVUS). Methods This is a pre-specified analysis of the PPG Global study (NCT04789317). We included stable patients with hemodynamically significant lesions (FFR ≤0.80) undergoing percutaneous coronary intervention (PCI) guided by IVUS. PPG was calculated from manual FFR pullbacks before PCI. Pathophysiological CAD patterns were classified as focal or diffuse based on the median PPG (0.62). Results A total of 261 patients (264 vessels) with PPG and IVUS were included. The mean age was 69±11 years, 77% were male, and 33% had diabetes mellitus. A significant correlation was observed between PPG and plaque burden (r=0.53, 95% CI 0.43–0.61, p<0.001). Vessels with focal CAD exhibited significantly higher plaque burden compared to those with diffuse CAD (83±6% vs. 76±8%, p<0.001). The prevalence of attenuated plaques was greater in vessels with high PPG (68% vs. 39%, p <0.001), while calcified plaques were more frequent in vessels with low PPG (60% vs. 78%, p=0.003). Conclusions In vessels with flow-limiting stenoses, high PPG is associated with increased plaque burden. Vessels with high PPG (focal disease) predominantly exhibited lipid-rich plaques, whereas those with low PPG (diffuse disease) had a greater calcium burden.