Identification of ischemia-causing lesions using coronary plaque quantification and changes in fractional flow reserve derived from computed tomography across the lesion.

BACKGROUND

This study sought to evaluate the association between coronary plaque characteristics, changes in the fractional flow reserve (FFR) derived from computed tomography across the lesion (ΔFFR), and lesion-specific ischemia using the FFR in patients with suspected or known coronary artery disease.

METHODS

The study assessed coronary computed tomography (CT) angiography stenosis, plaque characteristics, ΔFFR, and FFR in 164 vessels of 144 patients. Obstructive stenosis was defined as stenosis ≥50%. An area under the receiver -operating characteristics curve (AUC) analysis was conducted to define the optimal thresholds for ΔFFR and the plaque variables. Ischemia was defined as a FFR of ≤0.80.

RESULTS

The optimal cut-off value of ΔFFR was 0.14. Low-attenuation plaque (LAP) ≥76.23 mm and a percentage aggregate plaque volume (%APV) ≥28.91% can be used to predict ischemia independent of other plaque characteristics. The addition of LAP ≥76.23 mm and %APV ≥28.91% improved the discrimination (AUC, 0.742 0.649, P=0.001) and reclassification abilities [category-free net reclassification index (NRI), 0.339, P=0.027; relative integrated discrimination improvement (IDI) index, 0.093, P<0.001] of the assessments compared to the stenosis evaluation alone, and the addition of information about ΔFFR ≥0.14 further increased the discrimination (AUC, 0.828 0.742, P=0.004) and reclassification abilities (NRI, 1.029, P<0.001; relative IDI, 0.140, P<0.001) of the assessments.

CONCLUSIONS

The addition of the plaque assessment and ΔFFR to the stenosis assessments improved the identification of ischemia compared to the stenosis assessment alone.