Hybrid near-infrared spectroscopy–intravascular ultrasound imaging: integrating plaque biology, procedural precision, and prognostic stratification in contemporary coronary intervention

Hybrid near-infrared spectroscopy-intravascular ultrasound (NIRS/IVUS) represents a major advancement in intracoronary imaging as it combines an ultra-high-resolution ultrasound image processing of the vessel lumen and atherosclerotic plaque with an automated algorithm for the detection and quantification of the plaque lipid-core. This unique feature allows for a detailed biologic assessment of the plaque composition and quantification beyond the conventional angiographic estimation of coronary artery stenosis severity. High lipidic atherosclerotic burden, as this is predominantly defined by maxLCBI 4mm ≥400, identifies high-risk vulnerable plaques and independently predicts future non-culprit major cardiovascular events and a higher risk of periprocedural myocardial injury during percutaneous coronary intervention (PCI). Segments with maxLCBI 4mm >400 carry a 3- to 4-fold higher risk of non-culprit events (LRP), and lesions combining plaque burden ≥70% with maxLCBI 4mm ≥324.7 have a 7% 4-year event rate (PROSPECT II). Emerging evidence from the PREVENT trial suggests that preventive PCI of imaging-defined vulnerable plaques may reduce future events, although this benefit was driven predominantly by ischaemia-driven revascularization and hospitalization rather than by reductions in death or myocardial infarction. This strategy therefore remains investigational, and it is not yet incorporated into major guideline recommendations. NIRS-IVUS has additionally been used to demonstrate the prognostic value of lipid reduction after successful PCI. In this review, we provide a mechanistic synthesis of key randomized trials (PROSPECT II, LRP, and PREVENT) and observational registries to summarize contemporary evidence for the use of NIRS/IVUS in cardiovascular risk stratification, vulnerable-plaque detection, and PCI optimization, including the potential prognostic implications of post-PCI residual lipid burden. We also present case examples and a proposed, investigational algorithm for integrating the NIRS/IVUS system into lesion-level clinical decision-making.