Large lipid-rich coronary plaques detected by near-infrared spectroscopy at non-stented sites in the target artery identify patients likely to experience future major adverse cardiovascular events

Optical windows for head tissues in near-infrared and short-wave infrared regions: Approaching transcranial light applications

Optical properties of the rat head tissues (brain cortex, cranial bone and scalp skin) are assessed, aiming at transcranial light applications such as optical imaging and phototherapy. The spectral measurements are carried out over the wide spectral range of 350 to 2800 nm, involving visible, near-infrared (NIR) and short-wave infrared (SWIR) regions. Four tissue transparency windows are considered: ~700 to 1000 nm (NIR-I), ~1000 to 1350 nm (NIR-II), ~1550 to 1870 nm (NIR-III or SWIR) and ~2100 to 2300 nm (SWIR-II). The values of attenuation coefficient and total attenuation length are determined for all windows and tissue types. The spectra indicate transmittance peaks in NIR, NIR-II and SWIR-II, with maximum tissue permeability for SWIR light. The use of SWIR-II window for the transcranial light applications is substantiated. Furthermore, absorbance of the head tissues is investigated in details, by defining and describing the characteristic absorption peaks in NIR-SWIR.

Precision Healthcare of Type 2 Diabetic Patients Through Implementation of Haptoglobin Genotyping

It is well-recognized that there is a need for medicine to migrate to a platform of delivering preventative care based on an individual's genetic make-up. The US National Research Council, the National Institute of Health and the American Heart Association all support the concept of utilizing genomic information to enhance the clinical management of patients. It is believed this type of precision healthcare will revolutionize health management. This current attitude of some of the most respected institutes in healthcare sets the stage for the utilization of the haptoglobin (Hp) genotype to guide precision management in type 2 diabetics (DM). There are three main Hp genotypes: 1-1, 2-1, 2-2. The Hp genotype has been studied extensively in (DM) and from the accumulated data it is clear that Hp should be considered in all DM patients as an additional independent cardiovascular disease (CVD) risk factor. In DM patients Hp2-2 generates five times increased risk of CVD compared to Hp1-1 and three times increased risk compared to Hp2-1. Data has also shown that carrying the Hp2-2 gene in DM compared to carrying an Hp1-1 genotype can increase the risk the microvascular complications of nephropathy and retinopathy. In addition, the Hp2-2 gene enhances post percutaneous coronary intervention (PCI) complications such as, in stent restenosis and need for additional revascularization during the first-year post PCI. Studies have demonstrated significant mitigation of CVD risk in Hp2-2 DM patients with administration of vitamin E and maintaining tight glycemic control. CVD is the leading cause of death and disability in DM as well-representing a huge financial burden. As such, evaluating the Hp genotype in DM patients can enhance the predictability and management of CVD risk.

Bilirubin acts as a multipotent guardian of cardiovascular integrity: more than just a radical idea

Bilirubin, a potentially toxic catabolite of heme and indicator of hepatobiliary insufficiency, exhibits potent cardiac and vascular protective properties. Individuals with Gilbert's syndrome (GS) may experience hyperbilirubinemia in response to stressors including reduced hepatic bilirubin excretion/increased red blood cell breakdown, with individuals usually informed by their clinician that their condition is of little consequence. However, GS appears to protect from all-cause mortality, with progressively elevated total bilirubin associated with protection from ischemic heart and chronic obstructive pulmonary diseases. Bilirubin may protect against these diseases and associated mortality by reducing circulating cholesterol, oxidative lipid/protein modifications, and blood pressure. In addition, bilirubin inhibits platelet activation and protects the heart from ischemia-reperfusion injury. These effects attenuate multiple stages of the atherosclerotic process in addition to protecting the heart during resultant ischemic stress, likely underpinning the profound reduction in cardiovascular mortality in hyperbilirubinemic GS. This review outlines our current knowledge of and uses for bilirubin in clinical medicine and summarizes recent progress in revealing the physiological importance of this poorly understood molecule. We believe that this review will be of significant interest to clinicians, medical researchers, and individuals who have GS.

Multimodality Intracoronary Imaging With Near-Infrared Spectroscopy and Intravascular Ultrasound in Asymptomatic Individuals With High Calcium Scores

BACKGROUND

This study sought to determine the frequency of large lipid-rich plaques (LRP) in the coronary arteries of individuals with high coronary artery calcium scores (CACS) and to determine whether the CACS correlates with coronary lipid burden.

METHODS AND RESULTS

Combined near-infrared spectroscopy and intravascular ultrasound was performed in 57 vessels in 20 asymptomatic individuals (90% on statins) with no prior history of coronary artery disease who had a screening CACS ≥300 Agatston units. Among 268 10-mm coronary segments, near-infrared spectroscopy images were analyzed for LRP, defined as a bright yellow block on the near-infrared spectroscopy block chemogram. Lipid burden was assessed as the lipid core burden index (LCBI), and large LRP were defined as a maximum LCBI in 4 mm ≥400. Vessel plaque volume was measured by quantitative intravascular ultrasound. Vessel-level CACS significantly correlated with plaque volume by intravascular ultrasound (r=0.69; P<0.0001) but not with LCBI by near-infrared spectroscopy (r=0.24; P=0.07). Despite a high CACS, no LRP was detected in 8 (40.0%) subjects. Large LRP having a maximum LCBI in 4 mm ≥400 were infrequent, found in only 5 (25.0%) of 20 subjects and in only 5 (1.9%) of 268 10-mm coronary segments analyzed.

CONCLUSIONS

Among individuals with a CACS ≥300 Agatston units mostly on statins, CACS correlated with total plaque volume but not LCBI. This observation may have implications on coronary risk among individuals with a high CACS considering that it is coronary LRP, rather than calcification, that underlies the majority of acute coronary events.

The Lipid-Rich Plaque Study of vulnerable plaques and vulnerable patients: Study design and rationale

BACKGROUND

It has been hypothesized that the outcome post-PCI could be improved by the detection and subsequent treatment of vulnerable patients and lipid-rich vulnerable coronary plaques (LRP). A near-infrared spectroscopy (NIRS) catheter capable of detecting LRP is being evaluated in The Lipid-Rich Plaque Study.

STUDY DESIGN

The LRP Study is an international, multicenter, prospective cohort study conducted in patients with suspected coronary artery disease (CAD) who underwent cardiac catheterization with possible ad hoc PCI for an index event. Patient level and plaque level events were detected by follow-up in the subsequent 2 years. Enrollment began in February 2014 and was completed in March 2016; a total of 1,562 patients were enrolled. Adjudication of new coronary event occurrence and de novo culprit lesion location during the 2-year follow-up is performed by an independent clinical end-points committee (CEC) blinded to NIRS-IVUS findings. The first analysis of the results will be performed when at least 20 de novo events have occurred for which follow-up angiographic data and baseline NIRS-IVUS measurements are available. It is expected that results of the study will be announced in 2018.

SUMMARY

The LRP Study will test the hypotheses that NIRS-IVUS imaging to detect LRP in patients can identify vulnerable patients and vulnerable plaques. Identification of vulnerable patients will assist future studies of novel systemic therapies; identification of localized vulnerable plaques would enhance future studies of possible preventive measures.

Recent Advances in Fluorescent Angioscopy for Molecular Imaging of Human Atherosclerotic Coronary Plaque

PURPOSE OF REVIEW

In vivo imaging of the native substances, including lipoproteins, that comprise human atherosclerotic plaques is currently beyond the scope of any available imaging techniques. Color and near-infrared fluorescent angioscopy (CFA and NIRFA, respectively) systems have been recently developed for molecular imaging of lipoproteins within the human coronary arterial wall ex vivo and/or in vivo. The author reviews recent findings on lipoprotein deposition in human coronary plaques obtained by these imaging techniques.

RECENT FINDINGS

Using specific biomarkers, native pro-atherogenic substances such as oxidized low-density lipoprotein (ox-LDL), LDL, triglycerides (TG), apolipoprotein B-100 (ApoB-100), and lysophosphatidylcholine (LPC), and the anti-atherogenic substance such as high-density lipoprotein (HDL) were visualized by CFA, and LDL and cholesterol by NIRFA, in coronary plaques obtained from autopsy subjects. The relationship between incidence and plaque morphology differed for each substance. The incidence of ox-LDL and LDL on color fluorescence microscopy correlated well with that observed using immunohistochemical techniques. During coronary catheterization in patients, ox-LDL, LDL, and HDL in coronary plaques were visualized by CFA or NIRFA.

CONCLUSIONS

Using CFA or NIRFA, the distribution of the major native pro-atherogenic and anti-atherogenic lipoproteins and their components within human coronary plaques can be evaluated ex vivo and/or in vivo. Fluorescent angioscopy could help our understanding of the molecular mechanisms of coronary atherosclerosis and in the evaluation of the effects of therapy targeting the substances comprising atherosclerotic coronary plaques.

Optical coherence tomography to identify the cause of an arrhythmic storm: A case report

A 56-year-old man experienced an aborted sudden death followed by an arrhythmic storm. Angiography revealed a non-severe lesion on the left circumflex artery that was treated medically but an arrhythmic storm recurred. A repeat angiogram was comparable but optical coherence tomography imaging revealed a ruptured plaque with intraluminal thrombosis. Percutaneous coronary intervention was performed and no arrhythmia recurred.