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

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 (RWS_max) 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.

This retrospective study included 89 lesions who underwent IVUS-NIRS. VP was defined as maxLCBI_4mm ≥325 and PB ≥70%. μFR and RWS_max 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.

μFR was inversely correlated with maxLCBI_4mm (r = -0.452, p < 0.001) and PB (r = -0.276, p = 0.009). RWS_max was positively correlated with maxLCBI_4mm (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 RWS_max (AUC = 0.80). In multivariable analysis, RWS_max remained independently associated with VP, whereas μFR lost statistical significance.

μFR and RWS_max were correlated with PB and maxLCBI_4mm. RWS_max demonstrated independent predictive ability to identify VP.