Influence of plaque characteristics on fractional flow reserve for coronary lesions with intermediate to obstructive stenosis: insights from integrated-backscatter intravascular ultrasound analysis

Abstract

The aim of this study was to determine the correlation between the fractional flow reserve (FFR) values and volumetric intravascular ultrasound (IVUS) parameters derived from classic gray-scale IVUS and integrated backscatter (IB)-IVUS, taking into account known confounding factors. Patients with unstable angina pectoris with the frequent development of vulnerable plaques often showed the discrepancy between the FFR value and the quantitative coronary angiography findings. Our target population was 107 consecutive subjects with 114 isolated lesions who were scheduled for elective coronary angiography. The FFR was calculated as the mean distal coronary pressure divided by the mean aortic pressure during maximal hyperemia. Various volumetric parameters such as lipid plaque volume (LPV) and percentage of LPV (%LPV) were measured using IB-IVUS. Simple and multivariate linear regression analysis was employed to evaluate the correlation between FFR values and various classic gray-scale IVUS and IB-IVUS parameters. The Akaike information criterion (AIC) was used to compare the goodness of fit in an each model. Both the %LPV (r = -0.24; p = 0.01) and LPV (r = -0.40; p < 0.01) were significantly correlated with the FFR value. Only the LPV (AIC = -147.0; p = 0.006) and %LPV (AIC = -152.9; p = 0.005) proved to be independent predictors for the FFR value even after the adjustment of known confounding factors. The volumetric assessment by IB-IVUS could provide better information in terms of the relationship between plaque morphology and the FFR values as compared to the classic IVUS 2-dimensional gray-scale analysis.

Association between fractional flow reserve and coronary plaque characteristics assessed by optical coherence tomography

“…In the present study, OCT-derived minimal lumen area and area stenosis are independent determinants for FFR, whereas morphometric plaque characteristics are not. These findings are consistent with previous intravascular ultrasound or OCT studies in which minimum lumen area or plaque area was associated with FFR [5,11,12], but the plaque composition such as necrotic core or dense calcium was not [5]. The finding that FFR and plaque characteristics are unrelated may result from an adaptive vascular response to aggravation of coronary atherosclerosis because positive vascular remodeling maintains the diameter of the lumen to some degree [13].…”

“…The finding that FFR and plaque characteristics are unrelated may result from an adaptive vascular response to aggravation of coronary atherosclerosis because positive vascular remodeling maintains the diameter of the lumen to some degree [13]. However, a recent study showed that the volume of lipid plaque measured by integrated backscatter intravascular ultrasound was significantly associated with FFR [12]. In the present study, the angle or longitudinal length of lipid pool was correlated to FFR in the univariate analysis, but it was not in the multivariable analysis.…”

Multimodality imaging of intermediate lesions: Data from FFR, OCT, NIRS-IVUS

“…Fractional flow reverse positive lesions had more lipids [13], presented higher PB and smaller MLA [14]. Furthermore, the length of the plaque and its volume positively correlated with FFR results as well [15].…”

Plaque Volume and Morphology are Associated with Fractional Flow Reserve Derived from Coronary Computed Tomography Angiography

“…Brown et al also reported no relationship between the invasive FFR value and the VH-IVUS derived plaque composition 21) . However, Sakurai et al reported that lipid plaque volume, evaluated using integrated backscatter IVUS, was significantly correlated with invasive FFR value 22) . Hüseyinova et al also reported that invasive FFR value negatively correlated with the necrotic core volume or presence of thin-cap fibroatheroma (TCFA) evaluated using VH-IVUS 23) .…”