Vulnerable coronary plaque identification: Murray's flow ratio and radial wall strain compared with IVUS-NIRS evaluation

Background Coronary vulnerable plaque (VP) identification is crucial for preventing acute events. Intravascular ultrasound with near-infrared spectroscopy (IVUS-NIRS) is a reference technique to assess plaque vulnerability by quantifying lipid core burden index (LCBI) and plaque burden (PB). Murray's flow ratio (μFR) and maximal radial wall strain (RWSmax) are new angiography-derived parameters that may stratify plaque risk profile. We aim to evaluate their ability to identify VP as defined by IVUS-NIRS. Methods This retrospective study included 89 lesions who underwent IVUS-NIRS. VP was defined as maxLCBI4mm ≥325 and PB ≥70%. μFR and RWSmax were calculated offline. Pearson/Spearman correlations assessed relationships with IVUS-NIRS parameters. Receiver operating characteristic (ROC) curve evaluated diagnostic performance for VP. Potential confounders were included in a multivariable model. Results μFR was inversely correlated with maxLCBI4mm (r = −0.452, p < 0.001) and PB (r = −0.276, p = 0.009). RWSmax was positively correlated with maxLCBI4mm (r = 0.597, p < 0.001) and PB (r = 0.294, p < 0.001). ROC analysis revealed good accuracy for identifying VP for both μFR (AUC = 0.71) and RWSmax (AUC = 0.80). In multivariable analysis, RWSmax remained independently associated with VP, whereas μFR lost statistical significance. Conclusions μFR and RWSmax were correlated with PB and maxLCBI4mm. RWSmax demonstrated independent predictive ability to identify VP.