Morphology of coronary artery lesions assessed by virtual histology intravascular ultrasound tissue characterization and fractional flow reserve

Fractional flow reserve (FFR) is an index of the physiological significance of a coronary stenosis. Patients who have lesions with a FFR of >0.80, even optimally treated with medication, have however a MACE rate ranging from 8 to 21%. Coronary plaques at high risk of rupture and clinical events can be also identified by virtual histology intravascular ultrasound (IVUS-VH) as plaques with high amount of necrotic core (NC) abutting the lumen. Aim of this exploratory study was to investigate whether the geometry and composition of lesions with FFR????0.80 were different from their counterparts. Fifty-five consecutive patients in whom FFR was clinically indicated on a moderate angiographic lesion, received also an imaging investigation on the same lesion with IVUS-VH. Data on plaque geometry and composition was analyzed. Patients were subdivided in two groups according to the value of FFR (> or ??0.80). Lesions with a FFR????0.80 (n?=?17) showed a slightly larger plaque burden than those with FFR?>?0.80 (n?=?38) (54.6?±?0.7% vs. 51.7?±?0.7% P?=?0.1). In addition, they tend to have less content of necrotic core than their counterparts (14.2?±?8% vs. 19.2?±?10.2%, P?=?0.08). No difference was found in the distribution of NC-rich plaques (fibroatheroma and thin-capped fibroatheroma) between groups (82% in FFR????0.80 vs. 79% in FFR?>?0.80, P?=?0.5). Although FFR????0.80 lesions have larger plaque size, they do not differ in composition from the ones with FFR?>?0.80. Further exploration in a large prospective study is needed to study whether the lesions with FFR?>?0.80 that are NC rich are the ones associated with the presence of clinical events at follow-up.