Association of coronary plaque burden with fractional flow reserve: should we keep attempting to derive physiology from anatomy?

Coronary computed tomography angiography (CTA) has been used increasingly for the diagnosis of coronary artery disease over the past decade. Compared to invasive coronary angiography (ICA), coronary CTA has the ability to visualize and quantify atherosclerotic plaque both calcified and non-calcified. Traditional measures of evaluating a coronary stenosis such as diameter stenosis, area stenosis, minimal lumen diameter and minimal luminal area are limited in their ability to predict its functional significance especially when diameter stenosis ranges between 30-69% (intermediate range). Measurement of invasive fractional flow reserve (FFR) is considered the gold standard for assessment of the hemodynamic significance of a stenosis. The current study by Nakazato et al. evaluates the performance of an emerging coronary CTA-derived anatomical measure "percent aggregate plaque volume" to improve the detection of hemodynamic significant stenosis as compared with invasive FFR.