Multimodality imaging of intermediate lesions: Data from fractional flow reserve, optical coherence tomography, near-infrared spectroscopy-intravascular ultrasound.

BACKGROUND: Fractional flow reserve (FFR) assesses a functional impact of the atheroma on the myocardial ischemia, but it does not take into account the morphology of the lesion. Previous optical coherence tomography (OCT), intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) studies presented their potential to detect vulnerable plaques, which is not possible by FFR assessment. With the following study, the intermediate lesions were assessed by FFR, OCT and combined NIRS-IVUS imaging to identify plaque vulnerability.

METHODS: Thirteen intermediate lesions were analyzed simultaneously by FFR, OCT and combined NIRS-IVUS imaging.

RESULTS: Two lesions were found to have FFR ≤ 0.80 (0.65 and 0.76). The other 11 lesions had FFR > 0.80 with a mean FFR 0.88 ± 0.049. Two lesions with FFR ≤ 0.80 had plaque burden (PB) > 70% and minimal lumen area (MLA) < 4 mm2, but neither of these 2 lesions were identified as OCT de-fined thin fibrous cap atheroma (TCFA), or NIRS-IVUS possible TCFA. Among the other 11 lesions with FFR > 0.80, 8 were identified as OCT-defined TCFA, 4 had PB > 70%, 6 had MLA < 4 mm2, 2 had both PB > 70% and MLA < 4 mm2, 3 lesions were identified as NIRS-IVUS possible TCFA, and 4 lesions had lipid core burden index > 400.

CONCLUSIONS: The FFR-negative lesions pose traits of vulnerability as assessed simultaneously by IVUS, OCT and NIRS imaging.