High reproducibility of lipid core burden measurements with near-infrared spectroscopy and intravascular ultrasound imaging catheter

Background Near-infrared spectroscopy combined with intravascular ultrasound (NIRS–IVUS) allows simultaneous assessment of plaque composition and vessel structure. The lipid core burden index (LCBI) and the maximum lipid core burden index over 4 mm ( max LCBI 4mm ) are established markers of lipid-rich and potentially vulnerable plaques. However real-world reproducibility data for these indices using the contemporary Dualpro™ NIRS–IVUS catheter is unknown. This study aimed to evaluate the reproducibility of LCBI and max LCBI 4mm across repeated NIRS–IVUS pullbacks performed within the same coronary segment using the current-generation catheter system. Methods This single-center study included consecutive patients who underwent percutaneous coronary intervention (PCI) with adjunctive NIRS–IVUS imaging and had repeated pullbacks of the same coronary segment during the procedure. LCBI and max LCBI 4mm were recorded for each pullback. Reproducibility was assessed using Spearman correlation and intraclass correlation coefficients (ICC), and consistency for the clinically relevant thresholds of max LCBI 4mm was evaluated. Results A total of 87 paired pullbacks were analyzed (37 pre-PCI, 15 post-lesion preparation, and 35 post-stenting). LCBI demonstrated excellent reproducibility (ρ = 0.95; ICC = 0.95) and max LCBI 4mm also showed strong reproducibility (ρ = 0.90; ICC = 0.91). The threshold of max LCBI 4mm > 400 was concordant between runs in 90% of cases, and the post-stent threshold of >200 showed concordance in 89% of cases. Conclusion The contemporary Dualpro™ NIRS–IVUS catheter provides highly reproducible measurements of both LCBI and max LCBI 4mm . These findings support the reliability of NIRS–IVUS for identifying lipid-rich plaques and strengthen its suitability for research and clinical applications focused on plaque vulnerability.