The impact of lipid rich plaque on coronary-microvascular-dysfunction evaluated by near-infrared spectroscopy IVUS and angiography-derived index of microcirculatory resistance after percutaneous-coron

Abstract Background Coronary microvascular dysfunction (CMD) after percutaneous coronary intervention (PCI) has been reported to be associated not only with periprocedural myocardial infarction, but also with poor prognosis. While index of microcirculatory resistance using pressure wire (invasive IMR) has been conventionally used to evaluate CMD, angio-derived IMR (angio-IMR) has recently emerged as a noninvasive method and has shown good correlation with invasive IMR. Previous investigations have already shown that the maximum value of LCBI for any of the 4-mm segments (maxLCBI4mm) by near-infrared spectroscopy IVUS (NIRS-IVUS) represents the degree of lipid rich plaque (LRP) and can predict microvascular obstruction after PCI. However, few studies have examined the relationship between maxLCBI4mm values assessed by NIRS-IVUS and the degree of CMD from physiological assessment, or the optimal maxLCBI4mm cut-off values to predict CMD after PCI. Purpose The purpose of this study was to define the relationship between LRP identified by NIRS-IVUS and CMD assessed by angio-IMR in coronary artery disease (CAD) patients and to determinate the optimal diagnostic cut-off values of maxLCBI4mm. Methods We retrospectively evaluated 101 consecutive patients who underwent PCI using NIRS-IVUS for CAD, excluding STEMI, at our hospital from November 2021 to January 2024. MaxLCBI4mm and angio-IMR were measured in culprit vessel before and after PCI. CMD was defined as angio-IMR≥25. ROC curve analysis was performed to determine the optimal cut-off values of maxLCBI4mm for angio-IMR≥25. Plaques with maxLCBI4mm values above the cut-off were defined as the LRP group. Results Of 101 patients, CMD after PCI occurred in 37 patients (37%). MaxLCBI4mm values were significantly higher in the CMD group compared to the non-CMD group (659±198 vs. 403±226, P<0.001). Figure 1 shows the results of ROC analysis for predicting the incidence of CMD after PCI. ROC analysis determined maxLCBI4mm≥579 (LRP group) as an optimal cut-off value associated with incidence of CMD (AUC=0.80, P<0.01, sensitivity=0.78, specificity=0.75). LRP group had significantly higher angio-IMR values and incidence of CMD than non-LRP group (24.7±7.8 vs. 19.1±7.2, P<0.01, 64% vs. 14%, P<0.01). Furthermore, Δangio-IMR (post PCI-Pre PCI) of the LRP group was significantly higher than that of the non-LRP group (Figure 2). On multivariable analysis, maxLCBI4mm≥579 emerged as the independent predictor of the incidence of CMD after PCI (OR=10.6, 95% CI=2.29-48.8, P<0.01). Conclusions The results of this study indicate that NIRS-IVUS-guided PCI is a useful predictor of the incidence of CMD after PCI.Figure 1Figure 2