Intravascular Ultrasound-derived Assessment of Hemodynamically Negative Lesions in NSTEACS Patients

After the angiographic screening for lesions with 40%-90% diameter stenosis, FFR will be performed according to standard protocol using the s5 console and PrimeWire Prestige PLUS coronary pressure wire (Volcano Corporation, San Diego, California). FFR is calculated as the ratio of mean distal intracoronary pressure measured by the pressure wire, and the mean arterial pressure measured through the coronary guiding catheter. An FFR ≤0.8 or \>90% diameter stenosis should result in a treatment decision for revascularization by PCI and lesions with FFR \>0.80 are defined as FNLs and should result in deferral of PCI.

After the successful FFR-guided PCI, IVUS will be performed in all FNLs with the ultrasound Imaging Catheter Atlantis™ SR Pro (40 MHz, mechanical-type transducer, 3.2 F, Boston Scientific Corporation, Natick, MA, USA). Quantitative analyses of grayscale IVUS include contouring external elastic membrane (EEM) and luminal borders and the measurement of EEM cross-sectional area (CSA), luminal CSA, plaque and media CSA, plaque burdenand remodeling index. Virtual assessment of plaque is performed with iMap software (QIvus 2.0; Medis Medical Imaging Systems, Leiden, The Netherlands). Plaque components are categorized as dense calcium, necrotic core, fibrofatty, and fibrous tissue and reported as absolute area and proportion of total plaque area.