Prognostic Implications of Comprehensive Whole Vessel Plaque Quantification Using Coronary Computed Tomography Angiography

Abstract

Background: The prognostic value of whole vessel plaque quantification has not been fully understood.

Objectives: We aimed to investigate the clinical relevance of whole vessel plaque quantification on coronary computed tomography angiography.

Methods: In a total of 1,013 vessels with fractional flow reserve (FFR) measurement and available coronary computed tomography angiography, high-risk plaque characteristics (HRPC) included minimum lumen area <4 mm2, plaque burden ≥70%, low attenuation plaque, positive remodeling, spotty calcification, and napkin-ring sign; and high-risk vessel characteristics (HRVC) included total plaque volume ≥306.5 mm3, fibrofatty and necrotic core volume ≥4.46 mm3, or percent total atheroma volume ≥32.2% in a target vessel, based on corresponding optimal cutoff values. Survival analysis for vessel-oriented composite outcome (VOCO) (a composite of cardiac death, target vessel myocardial infarction, or target vessel revascularization) at 5 years was performed using marginal Cox proportional hazard models.

Results: Whole vessel plaque quantification had incremental predictability in addition to % diameter stenosis and HRPC (P < 0.001) in predicting FFR ≤0.80. Among 517 deferred vessels based on FFR >0.80, the number of HRVC was significantly associated with the risk of VOCO (HR: 2.54; 95% CI: 1.77-3.64) and enhanced the predictability for VOCO of % diameter stenosis and the number of HRPC (P < 0.001). In a landmark analysis at 2 years, the number of HRVC showed sustained prognostic implications beyond 2 years, but the number of HRPC did not.

Conclusions: Whole vessel plaque quantification can provide incremental predictability for low FFR and additive prognostic value in deferred vessels with high FFR over anatomical severity and lesion plaque characteristics. (CCTA-FFR Registry for Risk Prediction; NCT04037163).

Keywords: CAD, coronary artery disease; CTA, computed tomography angiography; FFNC, fibrofatty and necrotic core; FFR, fractional flow reserve; HRPC, high-risk plaque characteristics; HRVC, high-risk vessel characteristics; MLA, minimum lumen area; VOCO, vessel-oriented composite outcome; atherosclerosis; coronary CT angiography; fractional flow reserve; plaque quantification.

Conflict of interest statement

This study was supported in part by an unrestricted research grant from St. Jude Medical (Abbott Vascular). The company had no role in study design, conduct, data analysis or manuscript preparation. Dr Lee has received a research grant from St. Jude Medical (Abbott Vascular) and Philips Volcano. Dr Doh has received a research grant from Philips Volcano. Dr Chen has served as a consultant for Microport and Boston Scientific International; and has received a grant from the National Natural Scientific Foundation of China. Prof Koo has received an institutional research grant from St. Jude Medical (Abbott Vascular) and Philips Volcano. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

© 2021 The Author(s).

Figures

Graphical abstract

Figure 1

The Association of FFR ≤0.80 With Whole Vessel Plaque Quantification The proportion of the vessels with FFR ≤0.80 increased with increasing quartile of total plaque volume, FFNC component volume, and percent total atheroma volume. FFNC = fibrofatty and necrotic core; FFR = fractional flow reserve.

Figure 2

Predictive Value of Whole Vessel Plaque Quantification for FFR ≤0.80 Whole vessel plaque quantification had incremental predictability for FFR ≤0.80 over % diameter stenosis and HRPC. HRPC was defined as MLA 2, plaque burden ≥70%, low attenuation plaque, positive remodeling, spotty calcification, and napkin-ring sign. Whole vessel plaque quantification included the measurement of total plaque volume, FFNC component volume, and percent total atheroma volume. FFNC = fibrofatty and necrotic core; FFR = fractional flow reserve; HRPC = high-risk plaque characteristics. MLA = minimum lumen area.

Figure 3

Cumulative Incidence of VOCO by Each Component of HRVC Each component of HRVC discriminated 5-year VOCO in the deferred vessels with FFR >0.80. HRVC was defined as a vessel with total plaque volume ≥306.5 mm3, FFNC component volume ≥4.46 mm3, and percent total atheroma volume ≥32.2%. HRVC = high-risk vessel characteristics; VOCO = vessel-oriented composite outcome; other abbreviations as in Figure 2.

Figure 4

Prognostic Implications of the Number of HRVC The risk of vessel-oriented composite outcome increased with an increment of the number of HRVC in the deferred vessels with fractional flow reserve >0.80. HRVC = high-risk vessel characteristics.

Figure 5

Incremental Prognostic Value of the Number of HRVC for VOCO The number of HRVC showed additive discrimination ability for VOCO over % diameter stenosis and the number of HRPC in the deferred vessels with FFR >0.80. The definition of HRVC and HRPC was the same as in Figures 2 and 3. Abbreviations as in Figure 3.

Central Illustration

Prognostic Implications of Whole Vessel Plaque Quantification Using CT Angiography Whole vessel plaque quantification included total plaque volume, FFNC component volume, and percent total atheroma volume. It had additive predictive value for FFR ≤0.80 over lesion-level stenosis severity and HRPC. The number of HRVC discriminated clinical outcomes and provided long-term prognostication in the deferred vessels with FFR >0.80. HRPC was defined as MLA 2, plaque burden ≥70%, low attenuation plaque, positive remodeling, spotty calcification, and napkin-ring sign. HRVC was defined as a vessel with total plaque volume ≥306.5 mm3, percent total atheroma volume ≥32.2%, and FFNC component volume ≥4.46 mm3.