Intracoronary near-infrared spectroscopy and the risk of future cardiovascular events

Abstract

ObjectivesThe objectives of this study were to investigate if findings by intracoronary near-infrared spectroscopy (NIRS) and intravascular ultrasound (IVUS) are associated with future cardiovascular events and if NIRS can differentiate culprit from non-culprit segments in patients with coronary artery disease.MethodsThe study included 144 patients with coronary artery disease undergoing percutaneous coronary intervention and combined NIRS-IVUS imaging at two Swedish hospitals. The NIRS-derived lipid core burden index (LCBI), the 4 mm segment with maximum LCBI (MaxLCBI4mm) and the IVUS-derived maximum plaque burden (MaxPB) were analysed within the culprit segment and continuous 10 mm non-culprit segments of the index culprit vessels. The association with future major adverse cardiovascular and cerebrovascular events (MACCE), defined as all-cause mortality, acute coronary syndrome requiring revascularisation and cerebrovascular events during follow-up was evaluated using multivariable Cox regressions. A receiver operating characteristic (ROC) analysis was performed to test the ability of NIRS to discriminate culprit against non-culprit segments.ResultsA non-culprit maxLCBI4mm ≥400 (HR: 3.67, 95% CI 1.46 to 9.23, p=0.006) and a non-culprit LCBI ≥ median (HR: 3.08, 95% CI 1.11 to 8.56, p=0.031) were both significantly associated with MACCE, whereas a non-culprit MaxPB ≥70% (HR: 0.61, 95% CI 0.08 to 4.59, p=0.63) was not. The culprit segments had larger lipid cores compared with non-culprit segments (MaxLCBI4mm 425 vs 74, p<0.001), and the ROC analysis showed that NIRS can differentiate culprit against non-culprit segments (c-statistics: 0.85, 95% CI 0.81 to 0.89).ConclusionA maxLCBI4mm ≥400 and LCBI ≥ median, assessed by NIRS in non-culprit segments of a culprit artery, were significantly associated with patient-level MACCE. NIRS furthermore adequately discriminated culprit against non-culprit segments in patients with coronary disease.

Recent Advances in Transducers for Intravascular Ultrasound (IVUS) Imaging

“…Even though IVUS imaging can provide the cross-sectional visualization of the coronary artery wall and the quantitative evaluation of the lumen size and plaque characteristics [146,147], its intrinsic limitations including the low spatial resolution and considerable noise hinder the detailed assessment of plaque composition and visualization of microfeatures of plaque that are associated with increased vulnerability [148][149][150]. In order to address these limitations and provide a complete assessment of coronary artery, over the past two decades, alternative intravascular imaging techniques, including optical coherence tomography (OCT) [151,152], near-infrared spectroscopic (NIRS) imaging [153,154], intravascular photoacoustic (IVPA) imaging [155,156], near infrared fluorescence (NIRF) imaging [157,158], time resolved fluorescence spectroscopic (TRFS) imaging [159,160] and fluorescence lifetime imaging (FLIM) [161,162], have been emerged as a result of the miniaturization of medical devices and advances in image processing. Since the working principles of these intravascular imaging modalities have been thoroughly reviewed elsewhere, this review will concentrate on their intravascular coronary imaging applications.…”

Carotid artery plaque composition and distribution: near-infrared spectroscopy and intravascular ultrasound analysis

“… 45–48 Different reports found an association between baseline LCBI and future coronary events. 46 , 49–52 In light of these findings and the abovementioned association between the magnitude of ESS and local progression of LCBI we believe that the observation of NIRS-derived LCPs in the proximal parts of AP might be translatable into clinical events. A less invasive estimation of ESS might possibly help with the choice between optimal medical therapy and invasive treatment.…”

Advances in Endoscopic Photoacoustic Imaging

“…In addition, both IVUS and IVOCT have limited sensitivity for studying chemical composition and quantifying tissue mechanical properties, which are key indicators of plaque vulnerability [121][122][123][124]. To obtain the chemical composition of a plaque, intravascular NIRF and NIRS capable of providing molecular contrast with high sensitivity have been applied to characterize the intralesion lipid content, but these techniques lack depth information [125][126][127][128][129]. Conversely, intravascular PA (IVPA) imaging is able to provide extremely high molecular contrast while maintaining the superior imaging depth of US imaging [50,130,131], which can map blood vessel wall and lipid content simultaneously.…”