Additive diagnostic value of atherosclerotic plaque characteristics to non-invasive FFR for identification of lesions causing ischaemia: results from a prospective international multicentre trial.

Objective: We evaluated the association between atherosclerotic plaque characteristics (APCs) by CT -including positive remodelling (PR), low attenuation plaque (LAP) and spotty calcification (SC)- and lesion ischaemia by fractional flow reserve (FFR).

Results: Two hundred and fifty-two patients (17 centres, five countries) underwent CT, FFR derived from CT (FFRCT) with invasive FFR performed for 407 coronary lesions. FFR ≤0.8 was indicative of lesion-specific ischaemia. CT diameter ≥50% stenosis was considered obstructive. APCs by CT were defined as: (1) PR, lesion diameter/reference diameter >1.10; (2) LAP, any voxel <30 HU; and (3) SC, nodular calcified plaque <3 mm. Odds ratios (OR) and area under the ROC curve (AUC) of APCs for lesion-specific ischaemia were analysed. PR, LAP and SC were associated with ischaemia, with a three to fivefold higher prevalence than in non-ischaemic lesions. Among individual APC, PR (OR 4.7, p<0.001), but not SC or LAP, was strongly associated with lesion-specific ischaemia and provided incremental prediction for lesion-specific ischaemia over CT stenosis plus FFRCT (AUC 0.87 vs. 0.83, p=0.002).

Conclusions: APCs' features -especially PR- by CT improve identification and reclassification of coronary lesions which cause ischaemia over CT stenosis and FFRCT.