A Clinical and Biomarker Scoring System to Predict the Presence of Obstructive Coronary Artery Disease

Plasma proteomics for prediction of subclinical coronary artery calcifications in primary prevention

BACKGROUND AND AIMS

Recent developments in high-throughput proteomic technologies enable the discovery of novel biomarkers of coronary atherosclerosis. The aims of this study were to test if plasma protein subsets could detect coronary artery calcifications (CAC) in asymptomatic individuals and if they add predictive value beyond traditional risk factors.

METHODS

Using proximity extension assays, 1,342 plasma proteins were measured in 1,827 individuals from the Impaired Glucose Tolerance and Microbiota (IGTM) study and 883 individuals from the Swedish Cardiopulmonary BioImage Study (SCAPIS) aged 50-64 years without history of ischaemic heart disease and with CAC assessed by computed tomography. After data-driven feature selection, extreme gradient boosting machine learning models were trained on the IGTM cohort to predict the presence of CAC using combinations of proteins and traditional risk factors. The trained models were validated in SCAPIS.

RESULTS

The best plasma protein subset (44 proteins) predicted CAC with an area under the curve (AUC) of 0.691 in the validation cohort. However, this was not better than prediction by traditional risk factors alone (AUC = 0.710, P = .17). Adding proteins to traditional risk factors did not improve the predictions (AUC = 0.705, P = .6). Most of these 44 proteins were highly correlated with traditional risk factors.

CONCLUSIONS

A plasma protein subset that could predict the presence of subclinical CAC was identified but it did not outperform nor improve a model based on traditional risk factors. Thus, support for this targeted proteomics platform to predict subclinical CAC beyond traditional risk factors was not found.

Cyclophilin C as a Novel Diagnostic and Prognostic Biomarker of Coronary Artery Diseases. A Systematic Review and Meta-Analysis

We aimed to perform a meta-analysis to investigate the value of Cyclophilin C as a diagnostic and prognostic biomarker in Coronary Artery Disease. PubMed, Web of Science, Scopus and Cochrane library databases were searched. The inclusion criteria were any randomized control trials or controlled observational studies that measured the levels of Cyclophilin C in Coronary Artery disease patients and healthy controls. We excluded case reports, case series, reviews, editorials and animal studies. After search of the literature, 4 studies were included in the meta-analysis with a total number of 454 individuals included in the study. The pooled analysis showed a significant association between CAD group and increased levels of Cyclophilin C (MD = 28.94, 95% confidence interval (CI) = 19.28-38.60, P-value < 0.00001). Subgroup analysis showed a significant association between acute and chronic CAD group with increased levels of cyclophilin c compared with the control group (MD = 35.98, 95% CI = 19.84-52.11, P-value < 0.0001) and (MD = 26.36, 95% CI = 21.87 to 30.85, P-value < 0.00001), respectively. The pooled effect estimate showed that the ROC area for the cyclophillin c as a diagnostic biomarker of CAD was (ROC= 0.880, 95% CI =0.844-0.917, P-value < 0.001). Our study revealed a significant association between acute and chronic coronary artery disease with increased levels of Cyclophilin C. Cyclophilin C could be used as a novel diagnostic and prognostic biomarker in acute and chronic CAD. More research is warranted to support our results.

Associations of Biomarkers of Kidney Tubule Health, Injury, and Inflammation with Left Ventricular Hypertrophy in Children with CKD

Key Points

Higher plasma and urine kidney injury molecule-1, urine monocyte chemoattractant protein-1, and lower urine alpha-1-microglobulin were associated with left ventricular hypertrophy, even after adjustment for confounders. Biomarkers of tubular injury, dysfunction, and inflammation may indicate the severity of kidney pathology and are associated with left ventricular hypertrophy.

Background

Left ventricular hypertrophy (LVH) is common in children with CKD and is associated with an increased risk of cardiovascular disease and mortality. We have shown that several plasma and urine biomarkers are associated with increased risk of CKD progression. As CKD is associated with LVH, we sought to investigate the association between the biomarkers and LVH.

Methods

In the CKD in Children Cohort Study, children aged 6 months to 16 years with an eGFR of 30–90 ml/min per 1.73 m2 were enrolled at 54 centers in the United States and Canada. We measured plasma biomarkers kidney injury molecule-1 (KIM-1), tumor necrosis factor receptor-1, tumor necrosis factor receptor-2, soluble urokinase-type plasminogen activator receptor and urine KIM-1, monocyte chemoattractant protein-1 (MCP-1), YKL-40, alpha-1-microglobulin (alpha-1m), and epidermal growth factor in stored plasma and urine collected 5 months after enrollment. Echocardiograms were performed 1 year after enrollment. We assessed the cross-sectional association between the log2 biomarker levels and LVH (left ventricular mass index greater than or equal to the 95th percentile) using a Poisson regression model, adjusted for age, sex, race, body mass index, hypertension, glomerular diagnosis, urine protein-to-creatinine ratio, and eGFR at study entry.

Results

Among the 504 children, LVH prevalence was 12% (n =59) 1 year after enrollment. In a multivariable-adjusted model, higher plasma and urine KIM-1 and urine MCP-1 concentrations were associated with a higher prevalence of LVH (plasma KIM-1 prevalence ratio [PR] per log2: 1.27, 95% confidence interval [CI], 1.02 to 1.58; urine KIM-1 PR: 1.21, 95% CI, 1.11 to 1.48; and urine MCP-1 PR: 1.18, 95% CI, 1.04 to 1.34). After multivariable adjustment for covariates, lower urine alpha-1m was also associated with a higher prevalence of LVH (PR: 0.90, 95% CI, 0.82 to 0.99).

Conclusions

Higher plasma and urine KIM-1, urine MCP-1, and lower urine alpha-1m were each associated with LVH prevalence in children with CKD. These biomarkers may better inform risk and help elucidate the pathophysiology of LVH in pediatric CKD.

Novel Biomarkers for Atherosclerotic Disease: Advances in Cardiovascular Risk Assessment

Atherosclerosis is a significant health concern with a growing incidence worldwide. It is directly linked to an increased cardiovascular risk and to major adverse cardiovascular events, such as acute coronary syndromes. In this review, we try to assess the potential diagnostic role of biomarkers in the early identification of patients susceptible to the development of atherosclerosis and other adverse cardiovascular events. We have collected publications concerning already established parameters, such as low-density lipoprotein cholesterol (LDL-C), as well as newer markers, e.g., apolipoprotein B (apoB) and the ratio between apoB and apoA. Additionally, given the inflammatory nature of the development of atherosclerosis, high-sensitivity c-reactive protein (hs-CRP) or interleukin-6 (IL-6) are also discussed. Additionally, newer publications on other emerging components linked to atherosclerosis were considered in the context of patient evaluation. Apart from the already in-use markers (e.g., LDL-C), emerging research highlights the potential of newer molecules in optimizing the diagnosis of atherosclerotic disease in earlier stages. After further studies, they might be fully implemented in the screening protocols.

Danish study of Non-Invasive Testing in Coronary Artery Disease 3 (Dan-NICAD 3): study design of a controlled study on optimal diagnostic strategy

INTRODUCTION

Current guideline recommend functional imaging for myocardial ischaemia if coronary CT angiography (CTA) has shown coronary artery disease (CAD) of uncertain functional significance. However, diagnostic accuracy of selective myocardial perfusion imaging after coronary CTA is currently unclear. The Danish study of Non-Invasive testing in Coronary Artery Disease 3 trial is designed to evaluate head to head the diagnostic accuracy of myocardial perfusion imaging with positron emission tomography (PET) using the tracers ⁸²Rubidium (⁸²Rb-PET) compared with oxygen-15 labelled water PET (¹⁵O-water-PET) in patients with symptoms of obstructive CAD and a coronary CT scan with suspected obstructive CAD.

METHODS AND ANALYSIS

This prospective, multicentre, cross-sectional study will include approximately 1000 symptomatic patients without previous CAD. Patients are included after referral to coronary CTA. All patients undergo a structured interview and blood is sampled for genetic and proteomic analysis and a coronary CTA. Patients with possible obstructive CAD at coronary CTA are examined with both ⁸²Rb-PET, ¹⁵O-water-PET and invasive coronary angiography with three-vessel fractional flow reserve and thermodilution measurements of coronary flow reserve. After enrolment, patients are followed with Seattle Angina Questionnaires and follow-up PET scans in patients with an initially abnormal PET scan and for cardiovascular events in 10 years.

ETHICS AND DISSEMINATION

Ethical approval was obtained from Danish regional committee on health research ethics. Written informed consent will be provided by all study participants. Results of this study will be disseminated via articles in international peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT04707859.

Potential roles of microRNAs and long noncoding RNAs as diagnostic, prognostic and therapeutic biomarkers in coronary artery disease

Coronary artery disease (CAD), which is mainly caused by atherosclerotic processes in coronary arteries, became a significant health issue. MicroRNAs (miRNAs), and long noncoding RNAs (lncRNAs), have been shown to be stable in plasma and could thereby be adopted as biomarkers for CAD diagnosis and treatment. MiRNAs can regulate CAD development through different pathways and mechanisms, including modulation of vascular smooth muscle cell (VSMC) activity, inflammatory responses, myocardial injury, angiogenesis, and leukocyte adhesion. Similarly, previously studies have indicated that the causal effects of lncRNAs in CAD pathogenesis and their utility in CAD diagnosis and treatment, has been found to lead to cell cycle transition, proliferation dysregulation, and migration in favour of CAD development. Differential expression of miRNAs and lncRNAs in CAD patients has been identified and served as diagnostic, prognostic and therapeutic biomarkers for the assessment of CAD patients. Thus, in the current review, we summarize the functions of miRNAs and lncRNAs, which aimed to identify novel targets for the CAD diagnosis, prognosis, and treatment.

Effects of Mineralocorticoid Receptor Blockade and Statins on Kidney Injury Marker 1 (KIM-1) in Female Rats Receiving L-NAME and Angiotensin II

Kidney injury molecule-1 (KIM-1) is a biomarker of renal injury and a predictor of cardiovascular disease. Aldosterone, via activation of the mineralocorticoid receptor, is linked to cardiac and renal injury. However, the impact of mineralocorticoid receptor activation and blockade on KIM-1 is uncertain. We investigated whether renal KIM-1 is increased in a cardiorenal injury model induced by L-NAME/ANG II, and whether mineralocorticoid receptor blockade prevents the increase in KIM-1. Since statin use is associated with lower aldosterone, we also investigated whether administering eiSther a lipophilic statin (simvastatin) or a hydrophilic statin (pravastatin) prevents the increase in renal KIM-1. Female Wistar rats (8-10 week old), consuming a high salt diet (1.6% Na+), were randomized to the following conditions for 14 days: control; L-NAME (0.2 mg/mL in drinking water)/ANG II (225 ug/kg/day on days 12-14); L-NAME/ANG II + eplerenone (100 mg/kg/day p.o.); L-NAME/ANG II + pravastatin (20 mg/kg/day p.o.); L-NAME/ANG II + simvastatin (20 mg/kg/day p.o.). Groups treated with L-NAME/ANG II had significantly higher blood pressure, plasma and urine aldosterone, cardiac injury/stroke composite score, and renal KIM-1 than the control group. Both eplerenone and simvastatin reduced 24-h urinary KIM-1 (p = 0.0046, p = 0.031, respectively) and renal KIM-1 immunostaining (p = 0.004, p = 0.037, respectively). Eplerenone also reduced renal KIM-1 mRNA expression (p = 0.012) and cardiac injury/stroke composite score (p = 0.04). Pravastatin did not affect these damage markers. The 24-h urinary KIM-1, renal KIM-1 immunostaining, and renal KIM-1 mRNA expression correlated with cardiac injury/stroke composite score (p < 0.0001, Spearman ranked correlation = 0.69, 0.66, 0.59, respectively). In conclusion, L-NAME/ANG II increases renal KIM-1 and both eplerenone and simvastatin blunt this increase in renal KIM-1.

Inflammation across universal definition of heart failure stages: the CASABLANCA study

AIM

We sought to investigate the association of inflammatory biomarkers with incident heart failure (HF) events in patients at different stages of HF.

METHODS AND RESULTS

Overall, 1231 study participants undergoing diagnostic coronary and/or peripheral angiography were categorized by Universal Definition of HF (UDHF) stage A (at risk), stage B (pre-HF), and stages C or D (HF, including end-stage). Twenty-four inflammatory biomarkers were collected prior to angiography and unsupervised machine learning categorized levels of inflammation into three groups (low, medium, and high). Cox proportional hazard regression was implemented to assess the associations of inflammation level with incident HF hospitalization in each UDHF stage. Using machine learning, study participants were grouped into low (n = 443), medium (n = 570) and high inflammation categories (n = 230). Significantly higher concentrations of natriuretic peptide, troponin, and soluble ST2 were observed among those with high inflammation levels (p < 0.001). During 3.7 years of follow-up, 123 (15.1%) HF hospitalizations occurred in stage A/B and 180 (41.8%) HF hospitalizations occurred in stage C/D. In multivariable model considering low inflammation level as a reference, among patients with stage A/B, the hazard ratio (HR) (95% confidence interval [CI]) of incident HF was 2.31 (1.40-3.80) for moderate inflammation level, and 4.16 (2.35-7.37) for high inflammation level. Among patients with stage C/D, the corresponding HR (95% CI) of HF hospitalization was 1.98 (1.28-3.04) for moderate inflammation level, and 2.69 (1.69-4.28) for high inflammation level.

CONCLUSION

Patterns of inflammation severity may have differing prognostic meaning across UDHF stages.

Liquid Biopsy in Coronary Heart Disease

Cardiovascular disease (CVD) remains the major cause of morbidity and mortality globally. Accumulating evidence indicates that coronary heart disease (CHD) contributes to the majority of cardiovascular deaths. With the development of precision medicine, the diagnosis and treatment of coronary heart disease are becoming more refined and individualized. Molecular diagnosis technology and individualized treatment are gradually applied to the clinical diagnosis and treatment of CHD. It is great significance to seek sensitive biological indicators to help early diagnosis and improve prognosis of CHD. Liquid biopsy is a minimally invasive technique, which is widely used to detect molecular biomarkers of tumors without invasive biopsy. Compared with the field of oncology, it is not easy to get the diseased tissue in CVD, especially CHD. Therefore, the idea of "fluid biopsy" is very attractive, and its progress may provide new and useful noninvasive indicators for CHD. By analyzing circulating cells or their products in blood, saliva, and urine samples, we can investigate the molecular changes that occur in each patient at a specific point in time, thus continuously monitoring the evolution of CHD. For example, the assessment of cell-free DNA (cfDNA) levels may help predict the severity of acute myocardial infarction and diagnose heart transplant rejection. Moreover, the unmethylated FAM101A gene may specifically track the cfDNA derived from cardiomyocyte death, which provides a powerful diagnostic biomarker for apoptosis during ischemia. In addition, the changes of plasma circulating miR-92 levels may predict the occurrence of acute coronary syndrome (ACS) onset in patients with diabetes. Liquid biopsy can reflect the disease state through patients' body fluids and may noninvasively provide dynamic and rich molecular information related to CHD. It has great application potential in early warning and auxiliary diagnosis, real-time monitoring of curative effect, medication guidance and exploration of drug resistance mechanism, prognosis judgment, and risk classification of CHD. This chapter will review the latest progress of liquid biopsy in accurate diagnosis and treatment of CHD, meanwhile explore the application status and clinical prospect of liquid biopsy in CHD, in order to improve the importance of precision medicine and personalized treatment in this field.

Use of artificial intelligence to assess the risk of coronary artery disease without additional (non-invasive) testing: validation in a low-risk to intermediate-risk outpatient clinic cohort

OBJECTIVES

Predicting the presence or absence of coronary artery disease (CAD) is clinically important. Pretest probability (PTP) and CAD consortium clinical (CAD2) model and risk scores used in the guidelines are not sufficiently accurate as the only guidance for applying invasive testing or discharging a patient. Artificial intelligence without the need of additional non-invasive testing is not yet used in this context, as previous results of the model are promising, but available in high-risk population only. Still, validation in low-risk patients, which is clinically most relevant, is lacking.

DESIGN

Retrospective cohort study.

SETTING

Secondary outpatient clinic care in one Dutch academic hospital.

PARTICIPANTS

We included 696 patients referred from primary care for further testing regarding the presence or absence of CAD. The results were compared with PTP and CAD2 using receiver operating characteristic (ROC) curves (area under the curve (AUC)). CAD was defined by a coronary stenosis >50% in at least one coronary vessel in invasive coronary or CT angiography, or having a coronary event within 6 months.

OUTCOME MEASURES

The first cohort validating the memetic pattern-based algorithm (MPA) model developed in two high-risk populations in a low-risk to intermediate-risk cohort to improve risk stratification for non-invasive diagnosis of the presence or absence of CAD.

RESULTS

The population contained 49% male, average age was 65.6±12.6 years. 16.2% had CAD. The AUCs of the MPA model, the PTP and the CAD2 were 0.87, 0.80, and 0.82, respectively. Applying the MPA model resulted in possible discharge of 67.7% of the patients with an acceptable CAD rate of 4.2%.

CONCLUSIONS

In this low-risk to intermediate-risk population, the MPA model provides a good risk stratification of presence or absence of CAD with a better ROC compared with traditional risk scores. The results are promising but need prospective confirmation.

Midkine—A novel player in cardiovascular diseases

Midkine (MK) is a 13-kDa heparin-binding cytokine and growth factor with anti-apoptotic, pro-angiogenic, pro-inflammatory and anti-infective functions, that enable it to partake in a series of physiological and pathophysiological processes. In the past, research revolving around MK has concentrated on its roles in reproduction and development, tissue protection and repair as well as inflammatory and malignant processes. In the recent few years, MK's implication in a wide scope of cardiovascular diseases has been rigorously investigated. Nonetheless, there is still no broadly accepted consensus on whether MK exerts generally detrimental or favorable effects in cardiovascular diseases. The truth probably resides somewhere in-between and depends on the underlying physiological or pathophysiological condition. It is therefore crucial to thoroughly examine and appraise MK's participation in cardiovascular diseases. In this review, we introduce the MK gene and protein, its multiple receptors and signaling pathways along with its expression in the vascular system and its most substantial functions in cardiovascular biology. Further, we recapitulate the current evidence of MK's expression in cardiovascular diseases, addressing the various sources and modes of MK expression. Moreover, we summarize the most significant implications of MK in cardiovascular diseases with particular emphasis on MK's advantageous and injurious functions, highlighting its ample diagnostic and therapeutic potential. Also, we focus on conflicting roles of MK in a number of cardiovascular diseases and try to provide some clarity and guidance to MK's multifaceted roles. In summary, we aim to pave the way for MK-based diagnostics and therapies that could present promising tools in the diagnosis and treatment of cardiovascular diseases.

Relation of High-Sensitivity Cardiac Troponin I and Obstructive Coronary Artery Disease in Patients Without Acute Myocardial Infarction

The relation of high-sensitivity cardiac troponin I (hs-cTnI) concentration and presence of obstructive coronary artery disease (CAD) in patients without myocardial infarction (MI) is unclear. Study participants selected from patients free of MI who underwent coronary angiography with or without intervention were enrolled, and hs-cTnI measured. A gradient boosting model was implemented to build a model for detection of CAD. Cox proportional hazard regression was used to assess the association of hs-cTnI and adverse cardiovascular (CV) outcome. Among 978 study participants, 607 patients (62%) had CAD. Higher concentrations of hs-cTnI were associated with chronic kidney disease, heart failure, CAD, male gender, current tobacco use, anemia, age, and low-density lipoprotein cholesterol. History of CAD, male gender, type 2 diabetes mellitus, hs-cTnI, anemia, age, and high-density lipoprotein cholesterol were the most influential factors for detection of CAD. The gradient boosting model had an area under the curve of 0.82, accuracy of 75%, sensitivity of 88%, specificity of 52%, positive predictive value of 76%, and negative predictive value of 72% for detection of CAD. Increase in 1 log unit of hs-cTnI was significantly associated with increased risk of incident MI (hazard ratio [HR] 1.34, 95% confidence interval [CI] 1.22 to 1.47, p <0.001), CV mortality (HR 1. 24, 95% CI 1.11 to 1.39, p <0.001), and composite of incident MI or CV mortality (HR 1.29, 95% CI 1.20 to 1.40, p <0.001). In conclusion, among patients without acute MI and CAD, higher concentrations of hs-cTnI were associated with the presence of CAD and linked to increased risk of future CV events. ClinicalTrials.gov Identifier: NCT00842868.

A Coronary Artery Disease Monitoring Model Built from Clinical Data and Alpha-1-Antichymotrypsin

Coronary artery disease (CAD) is one of the most common subtypes of cardiovascular disease. The progression of CAD initiates from the plaque of atherosclerosis and coronary artery stenosis, and eventually turns into acute myocardial infarction (AMI) or stable CAD. Alpha-1-antichymotrypsin (AACT) has been highly associated with cardiac events. In this study, we proposed incorporating clinical data on AACT levels to establish a model for estimating the severity of CAD. Thirty-six healthy controls (HCs) and 162 CAD patients with stenosis rates of <30%, 30−70%, and >70% were included in this study. Plasma concentration of AACT was determined by enzyme-linked immunosorbent assay (ELISA). The receiver operating characteristic (ROC) curve analysis and associations were conducted. Further, five machine learning models, including decision tree, random forest, support vector machine, XGBoost, and lightGBM were implemented. The lightGBM model obtained a sensitivity of 81.4%, a specificity of 67.3%, and an area under the curve (AUC) of 0.822 for identifying CAD patients with a stenosis rate of <30% versus >30%. In this study, we provided a demonstration of a monitoring model with clinical data and AACT.

Midkine and chronic kidney disease-associated multisystem organ dysfunctions

Chronic kidney disease (CKD) is a progressive multisystem condition with yet undefined mechanistic drivers and multiple implicated soluble factors. If identified, these factors could be targeted for therapeutic intervention for a disease that currently lacks specific treatment. There is increasing preclinical evidence that the heparin/endothelial glycocalyx-binding molecule midkine (MK) has a pathological role in multiple CKD-related, organ-specific disease processes, including CKD progression, hypertension, vascular and cardiac disease, bone disease and CKD-related cancers. Concurrent with this are studies documenting increases in circulating and urine MK proportional to glomerular filtration rate (GFR) loss in CKD patients and evidence that administering soluble MK reverses the protective effects of MK deficiency in experimental kidney disease. This review summarizes the growing body of evidence supporting MK's potential role in driving CKD-related multisystem disease, including MK's relationship with the endothelial glycocalyx, the deranged MK levels and glycocalyx profile in CKD patients and a proposed model of MK organ interplay in CKD disease processes and highlights the importance of ongoing research into MK's potential as a therapeutic target.

Relationships between subendocardial perfusion impairment, arterial stiffness and orthostatic hypotension in hospitalized elderly individuals

BACKGROUND

Orthostatic hypotension is an independent risk factor for cardiovascular morbidity and mortality. Arterial stiffness has been shown to be a pathophysiological mechanism linking orthostatic hypotension and increased cardiovascular risk. This study aims to evaluate the relationship between arterial stiffness, orthostatic hypotension and subendocardial viability ratio (SEVR) and moreover to identify the main predictors of orthostatic hypotension, carotid-femoral pulse wave velocity (PWV-cf) and SEVR.

METHODS

Seventy-five patients were enrolled (mean age 82.95 ± 6.45) in Verona's AOUI Geriatric ward. They underwent blood pressure, heart rate, body weight measurements and also comorbidity, arterial stiffness (PWV-cf measured by applanation tonometry), SEVR and biochemical indexes.

RESULTS

Prevalence of orthostatic hypotension was 46.6%. Even after adjustment for age, sex, glomerular filtration rate and mean arterial pressure, SEVR values corrected for arterial oxygen and haemoglobin content were statistically lower in orthostatic hypotension patients (P = 0.05) and PWV-cf values were statistically higher in orthostatic hypotension individuals (P = 0.042). In a binary logistic regression, PWV-cf was the only significant predictor of orthostatic hypotension (odds ratio 1.123; P = 0.039; confidence interval = 1.006--1.17).In a backward logistic regression model sex, creatinine clearance and orthostatic hypotension were significant predictors of SEVR corrected for O2 content. Mean arterial pressure, creatinine clearance and orthostatic hypotension were significant predictors of PWV-cf.

CONCLUSION

This study shows that orthostatic hypotension is related to increased arterial stiffness, confirming its higher prevalence in elderly patients. Orthostatic hypotension was also associated with reduced values of corrected SEVR, showing a relevant consequence of orthostatic hypotension on subendocardial perfusion impairment.

Midkine: A multifaceted driver of atherosclerosis

Atherosclerosis constitutes the pathological basis of life-threatening events, including heart attack and stroke. Midkine is a heparin-binding growth factor and forms a small protein family with pleiotrophin. Under inflammatory or hypoxic conditions, midkine expression is up-regulated. Upon binding to its receptors, midkine can activate multiple signal pathways to regulate cell survival and migration, epithelial-to-mesenchymal transition, and oncogenesis. Circulating midkine levels are significantly increased in patients with essential hypertension, obesity or severe peripheral artery disease. Importantly, midkine exerts a proatherogenic effect by altering multiple pathophysiological processes involving atherogenesis, including macrophage lipid accumulation, vascular inflammation, neointima formation, insulin resistance and macrophage apoptosis. Midkine represents a potential therapeutic target for atherosclerosis-associated diseases. This review described the structure characteristics, expression patterns and signal transduction pathways of midkine with an emphasis on its role in atherosclerosis.

Impact of train/test sample regimen on performance estimate stability of machine learning in cardiovascular imaging

As machine learning research in the field of cardiovascular imaging continues to grow, obtaining reliable model performance estimates is critical to develop reliable baselines and compare different algorithms. While the machine learning community has generally accepted methods such as k-fold stratified cross-validation (CV) to be more rigorous than single split validation, the standard research practice in medical fields is the use of single split validation techniques. This is especially concerning given the relatively small sample sizes of datasets used for cardiovascular imaging. We aim to examine how train-test split variation impacts the stability of machine learning (ML) model performance estimates in several validation techniques on two real-world cardiovascular imaging datasets: stratified split-sample validation (70/30 and 50/50 train-test splits), tenfold stratified CV, 10 × repeated tenfold stratified CV, bootstrapping (500 × repeated), and leave one out (LOO) validation. We demonstrate that split validation methods lead to the highest range in AUC and statistically significant differences in ROC curves, unlike the other aforementioned approaches. When building predictive models on relatively small data sets as is often the case in medical imaging, split-sample validation techniques can produce instability in performance estimates with variations in range over 0.15 in the AUC values, and thus any of the alternate validation methods are recommended.

Gaining Efficiency in Clinical Trials With Cardiac Biomarkers: JACC Review Topic of the Week

The momentum of cardiovascular drug development has slowed dramatically. Use of validated cardiac biomarkers in clinical trials could accelerate development of much-needed therapies, but biomarkers have been used less for cardiovascular drug development than in therapeutic areas such as oncology. Moreover, there are inconsistences in biomarker use in clinical trials, such as sample type, collection times, analytical methods, and storage for future research. With these needs in mind, participants in a Cardiac Safety Research Consortium Think Tank proposed the development of international guidance in this area, together with improved quality assurance and analytical methods, to determine what biomarkers can reliably show. Participants recommended the development of systematic methods for sample collection, and the archiving of samples in all cardiovascular clinical trials (including creation of a biobank or repository). The academic and regulatory communities also agreed to work together to ensure that published information is fully and clearly expressed.

Study of three novel biomarkers, MR-proADM, midkine, and stromelysin2, and peripheral atherosclerosis in a Chinese Han population: A case-control study

Midregional pro-adrenomedullin (MR-proADM), midkine, and stromelysin2 (ST2) are novel cardiac biomarkers associated with heart failure and atherosclerotic diseases like stable ischemic disease and acute coronary syndrome. The potential association between these three biomarkers and peripheral artery disease (PAD) remains unclear. The aim of this study was to assess the correlation between these three biomarkers and their association with PAD in the Chinese Han population. This study included 224 patients suspected of having coronary artery disease (CAD). All subjects underwent coronary angiography and carotid and subclavian ultrasound assessment for detection of coronary and peripheral atherosclerosis and were divided into two groups according to whether they had PAD or not. Pearson’s correlation coefficient r was calculated, and multivariable logistic regression analysis was conducted to represent the associations of these biomarkers and PAD. The study included 133 patients with PAD and 91 non-PAD controls and these two groups had similar values for age, ST2, hematocrit, hemoglobin, red blood cell counts, creatinine and CAD ratio, smoking, and type 2 diabetes (all p > 0.05). Compared with non-PAD controls, patients with PAD had lower levels of MR-proADM and midkine and higher levels of TC, LDL-C, and fasting blood sugar (FBS) (all p < 0.05). MR-proADM was positively and ST2 negatively correlated with midkine (all p < 0.05). Compared with females, male patients had higher values of MR-proADM ( p < 0.05) and similar levels of ST2 and midkine (all p > 0.05). Multivariable regression analysis identified FBS as a risk predictor (OR: 1.163, 95% CI: 1.108–1.401, p = 0.014) and MR-proADM as a protective factor (OR: 0.720, 95% CI: 0.529–0.920, p = 0.037) of PAD. Three novel biomarkers, MR-proADM, midkine, and ST2, are internally related, and MR-proADM is gender-specific and a protective factor of peripheral atherosclerosis in the Chinese Han population studied. Clinical Trial: ChiCTR-DDD-17013908

Circulating microRNA as a Biomarker for Coronary Artery Disease

Coronary artery disease (CAD) is the leading cause of sudden cardiac death in adults, and new methods of predicting disease and risk-stratifying patients will help guide intervention in order to reduce this burden. Current CAD detection involves multiple modalities, but the consideration of other biomarkers will help improve reliability. The aim of this narrative review is to help researchers and clinicians appreciate the growing relevance of miRNA in CAD and its potential as a biomarker, and also to suggest useful miRNA that may be targets for future study. We sourced information from several databases, namely PubMed, Scopus, and Google Scholar, when collating evidentiary information. MicroRNAs (miRNA) are short, noncoding RNAs that are relevant in cardiovascular physiology and pathophysiology, playing roles in cardiac hypertrophy, maintenance of vascular tone, and responses to vascular injury. CAD is associated with changes in miRNA expression profiles, and so are its risk factors, such as abnormal lipid metabolism and inflammation. Thus, they may potentially be biomarkers of CAD. Nevertheless, there are limitations in using miRNA. These include cost and the presence of several confounding factors that may affect miRNA profiles. Furthermore, there is difficulty in the normalisation of miRNA values between published studies, due to pre-analytical variations in samples.

Derivation and External Validation of a High-Sensitivity Cardiac Troponin-Based Proteomic Model to Predict the Presence of Obstructive Coronary Artery Disease

Background

Current noninvasive modalities to diagnose coronary artery disease (CAD) have several limitations. We sought to derive and externally validate a hs‐cTn (high‐sensitivity cardiac troponin)–based proteomic model to diagnose obstructive coronary artery disease.

Methods and Results

In a derivation cohort of 636 patients referred for coronary angiography, predictors of ≥70% coronary stenosis were identified from 6 clinical variables and 109 biomarkers. The final model was first internally validated on a separate cohort (n=275) and then externally validated on a cohort of 241 patients presenting to the ED with suspected acute myocardial infarction where ≥50% coronary stenosis was considered significant. The resulting model consisted of 3 clinical variables (male sex, age, and previous percutaneous coronary intervention) and 3 biomarkers (hs‐cTnI [high‐sensitivity cardiac troponin I], adiponectin, and kidney injury molecule‐1). In the internal validation cohort, the model yielded an area under the receiver operating characteristic curve of 0.85 for coronary stenosis ≥70% (P<0.001). At the optimal cutoff, we observed 80% sensitivity, 71% specificity, a positive predictive value of 83%, and negative predictive value of 66% for ≥70% stenosis. Partitioning the score result into 5 levels resulted in a positive predictive value of 97% and a negative predictive value of 89% at the highest and lowest levels, respectively. In the external validation cohort, the score performed similarly well. Notably, in patients who had myocardial infarction neither ruled in nor ruled out via hs‐cTnI testing (“indeterminate zone,” n=65), the score had an area under the receiver operating characteristic curve of 0.88 (P<0.001).

Conclusions

A model including hs‐cTnI can predict the presence of obstructive coronary artery disease with high accuracy including in those with indeterminate hs‐cTnI concentrations.

A Novel Laboratory-Based Model to Predict the Presence of Obstructive Coronary Artery Disease

Commonly used tools to assess the probability of obstructive-coronary artery disease (CAD) were derived based on Caucasian cohorts, with their performance in China is still unknown. Furthermore, most were established based on non-laboratory variables, contributing to the limited predictive ability to some extent. Thus, we developed and internally validated a laboratory-based model with data from a Chinese cohort of 8963 inpatients, with suspected stable chest pain, referred to catheter-based coronary angiography (CAG) from September 2007 to April 2019, and then compared the present model's performance with the four most commonly used prediction tools, Coronary Artery Disease Consortium 1/2 Score (CAD1/2), Duke clinical score (DCS), and Diamond-Forrester score (DF). The final model was developed by random forest method, including 8 predictors derived from 70 variables. Five-fold cross-validation was performed to evaluate the model's prediction accuracy. In the external validation set, the present model showed a superior area under the receiver-operating curve (0.816), followed by DCS (0.66), CAD2 (0.61), CAD1 (0.59) and at last DF (0.58), respectively. Furthermore, the present model correctly classified 74.4% of obstructive-CAD patients as high-risk, and correctly classified more than one third of non-obstructive-CAD patients as low-risk. The present model's net reclassification improvement (NRI) showed a significant positive reclassification over CAD1 (NRI = 0.60, P < 0.001), DF (NRI = 0.59, P < 0.001), CAD2 (NRI = 0.57, P < 0.001), and DCS (NRI = 0.43, P < 0.001). Decision curve analysis demonstrated that the present model provided a larger net benefit compared with CAD1/2, DCS, and DF. In conclusion, the novel model, using 8 laboratory and non-laboratory variables, performed well in risk stratifying patients with suspected chest pain regarding the presence of obstructive-CAD in the present Chinese cohort.

Application of a machine learning-driven, multibiomarker panel for prediction of incident cardiovascular events in patients with suspected myocardial infarction

Background: In patients with suspected myocardial infarction (MI), we sought to validate a machine learning-driven, multibiomarker panel for prediction of incident major adverse cardiovascular events (MACE). Methodology & results: A previously described prognostic panel for MACE consisting of four biomarkers was measured in 748 patients with suspected MI. The investigated end point was incident MACE within 1 year. The prognostic value of a continuous score and an optimal cut-off was investigated. The area under the curve was 0.86 for the overall model. Using the optimal cut-off resulted in a negative predictive value of 99.4% for incident MACE. Patients with an elevated prognostic score were at high risk for MACE. Conclusion: Among patients with suspected MI, we validated a multibiomarker panel for predicting 1-year MACE. Clinical Trial Registration: NCT02355457 (ClinicalTrials.gov).

Association of an HDL Apolipoproteomic Score With Coronary Atherosclerosis and Cardiovascular Death

BACKGROUND

Concentrations of circulating apolipoproteins are strongly linked to risk for coronary artery disease (CAD). The relative importance of the additional knowledge of apolipoprotein concentrations within specific lipoprotein species for CAD risk prediction is limited.

OBJECTIVES

This study sought to evaluate the performance of a high-density lipoprotein (HDL) apolipoproteomic score, based on targeted mass spectrometry of HDL-associated apolipoproteins, for the detection of angiographic CAD and outcomes.

METHODS

HDL-associated apolipoprotein (apo) A-1, apoC-1, apoC-2, apoC-3, and apoC-4 were measured in 943 participants without prevalent myocardial infarction (MI) referred for coronary angiography in the CASABLANCA (Catheter Sampled Blood Archive in Cardiovascular Diseases) study. A composite HDL apolipoproteomic score (pCAD) was associated with likelihood of obstructive CAD (≥70% lesion in ≥1 vessel) and with incident cardiovascular outcomes over 4-year follow-up.

RESULTS

There were 587 (62.2%) patients with coronary stenosis. The pCAD score was associated with the presence of obstructive CAD (odds ratio: 1.39; 95% confidence interval [CI]: 1.14 to 1.69; p < 0.001), independently of conventional cardiovascular risk factors including circulating plasma apoA-1 and apoB. The C-index for pCAD was 0.63 (95% CI: 0.59 to 0.67) for the presence of obstructive CAD. Although pCAD was not associated with cardiovascular mortality among all individuals (hazard ratio: 1.24; 95% CI: 0.93 to 1.66; p = 0.15), there was evidence of association for individuals with obstructive CAD (hazard ratio: 1.48; 95% CI: 1.07 to 2.05; p = 0.019).

CONCLUSIONS

An HDL apolipoproteomic score is associated with the presence of CAD, independent of circulating apoA-1 and apoB concentrations and other conventional cardiovascular risk factors. Among individuals with CAD, this score may be independently associated cardiovascular death. (The CASABLANCA Study: Catheter Sampled Blood Archive in Cardiovascular Diseases [CASABLANCA]; NCT00842868).

Heparin Administration, but Not Myocardial Ischemia or Necrosis, Leads to Midkine Elevation

Midkine (MK) is a heparin-binding growth factor, whose role as a biomarker of coronary artery disease, myocardial ischaemia and necrosis has not been well measured. This study quantified serial MK levels in patients undergoing coronary angiography (CA) and identified factors associated with MK. In this single-centre, parallel cohort study, forty patients undergoing CA had arterial samples collected prior, 10 and 20 min after heparin administration. Four groups were examined: 1-stable coronary artery disease (CAD) without percutaneous coronary intervention (PCI); 2-stable CAD for elective PCI; 3-non-ST elevation myocardial infarction (NSTEMI) with or without PCI; 4-ST elevation myocardial infarction (STEMI) with primary PCI. Groups 1, 2 and 4 were heparin naïve, allowing assessment of the effects of myocardial necrosis between baseline levels; group 3 had received low-molecular-weight heparin. MK levels were analysed by ELISA. Median MK at baseline did not differ between groups, demonstrating that myocardial ischaemia or necrosis does not affect MK levels. Heparin administration had an immediate effect on median MK at 10 min, showing an average 500-fold increase that is dose-dependent (R² = 0.35, p = 0.001). Median MK levels remained elevated at 20 min following heparin administration. Multivariate analysis showed that the estimated glomerular filtration rate (eGFR) was the only predictor of elevated baseline MK (p = 0.02). Baseline MK did not correlate with high-sensitivity troponin-I (HsTnI) taken just before CA (p = 0.97), or peak HsTnI during admission (p = 0.74). MK is not a reliable marker of myocardial ischaemia or necrosis. MK increased significantly in all patients following heparin administration in a dose-dependent manner.

Incidence, Clinical Characteristics, and Impact of Acute Coronary Syndrome Following Transcatheter Aortic Valve Replacement

OBJECTIVES

The authors sought to assess the incidence, predictors, management, and prognosis of acute coronary syndrome (ACS) following TAVR.

BACKGROUND

About one-half of the patients undergoing transcatheter aortic valve replacement (TAVR) have concurrent coronary artery disease (CAD). However, the occurrence and clinical impact of coronary events following TAVR remain largely unknown.

METHODS

Consecutive patients undergoing TAVR in our institution between May 2007 and November 2017 were included. Patients were followed at 1, 6, and 12 months, and yearly thereafter. ACS was diagnosed and classified according to the Third Universal Definition of Myocardial Infarction.

RESULTS

A total of 779 patients (mean age 79 ± 9 years, 52% male, mean STS: 6.8 ± 5.1%) were included, 68% of which had a history of CAD. At a median follow-up of 25 (interquartile range: 10 to 44) months, 78 patients (10%) presented at least 1 episode of ACS, with one-half of the events occurring within the year following TAVR. Clinical presentation was type 2 non-ST-segment elevation myocardial infarction (35.9%), unstable angina (34.6%), type 1 non-ST-segment elevation myocardial infarction (28.2%), and ST-segment elevation myocardial infarction (1.3%). Male sex (hazard ratio [HR]: 2.19; 95% confidence interval [CI]: 1.36 to 3.54; p = 0.001), prior CAD (HR: 2.78; 95% CI: 1.50 to 5.18; p = 0.001), and nontransfemoral approach (HR: 1.71; 95% CI: 1.04 to 2.75; p = 0.035) were independently associated with ACS. Coronary angiography was performed in 53 (67.9%) patients with ACS, and 30 of them (56.6%) underwent percutaneous coronary intervention. In-hospital death rate at the time of the ACS episode was 3.8%. At a median follow-up of 21 (interquartile range: 8 to 34) months post-ACS, all-cause and cardiovascular death rates were 37.3% and 25.3%, respectively.

CONCLUSIONS

Approximately one-tenth of patients undergoing TAVR were readmitted for an ACS after a median follow-up of 25 months. Male sex, prior CAD, and nontransfemoral approach were independent predictors of ACS. ACS was associated with high midterm mortality.

Systemic Inflammation in Severe Obese Patients Undergoing Surgery for Obesity and Weight-Related Diseases

Background

Obesity is a worldwide disease related to genetic, environmental, and behavioral factors, and it is associated with high rates of morbidity and mortality. Recently, obesity has been characterized by a low-grade inflammatory state known as inflammome indicated by chronic increases in circulating concentrations of inflammatory markers. The purpose of this study was to evaluate the effect of weight loss induced by surgery for obesity and weight-related diseases on pro-inflammatory cytokine (TNF-α) and anti-inflammatory adipokine (adiponectin) levels, and on an adipose-derived hormone (leptin) in severely obese subjects.

Methods

This randomized, controlled trial involved 55 severe obese patients (50 women, age 18–63 years, and body mass index of 35.7–63 kg/m²) who underwent bariatric surgery (BS). Patients with a BMI > 65 kg/m² and clinical and mental instability, or significant and unrealistic expectations of surgery were excluded. Blood samples were collected during the fasting period to analyze tumor necrosis factor alpha (TNF-α), adiponectin, and leptin levels by enzyme-linked immunosorbent assay.

Results

At baseline, no significant difference was observed in the anthropometric, demographic, clinical characteristics and biochemistry and inflammatory markers between the control group (CG) and bariatric surgery group (BSG). The same finding was also observed when we compared the baseline variables to those at the 6-month follow-up in the CG. However, the same variables in the BSG group were significantly different between baseline and the 6-month follow-up after BS.

Conclusions

Weight loss induced by surgery for obesity and weight-related diseases reduced the inflammome state in severely obese patients.

Role of IGFBP1 in the senescence of vascular endothelial cells and severity of aging‑related coronary atherosclerosis

The senescence of vascular endothelial cells (ECs) plays a critical role in aging-related cardiovascular diseases. We previously reported the causal relation of Jagged1 in ECs and the thickening of the arterial wall in aging mice. The aim of the present study was to further investigate the correlation between insulin-like growth factor-binding protein 1 (IGFBP1), one of the secretory proteins regulated by Jagged1, and the severity of coronary atherosclerosis and patient age, as well as its effect on EC senescence. First, microarray analysis was performed to screen the differentially expressed genes regulated by Jagged1 in human coronary arterial ECs (HCAECs). Inhibition of the Jagged1 expression using a small interfering RNA knockdown method in HCAECs led to the upregulation of 17 and the downregulation of 78 genes by >3-fold, and IGFBP1 was confirmed to be a secretory protein expressed by HCAECs and regulated by Jagged1. Subsequently, in 112 consecutively enrolled patients with acute chest pain who underwent coronary angiography, the circulating level of IGFBP1 was found to be positively correlated with age (r=0.512, P<0.001) and Synergy between PCI with TAXUS and Cardiac Surgery (SYNTAX) score (r=0.409, P<0.001). Among age-comparable patients, the circulating IGFBP1 level was found to be increased in patients with higher SYNTAX scores. In cultured HCAECs, IGFBP1 was shown to protect ECs against passage- or H₂O₂-induced senescence, and these protective effects of IGFBP1 may be partially reversed by LY294002, a known Akt signaling inhibitor. Therefore, the results of the present study suggested that, as a downstream protein of Jagged1, IGFBP1 was correlated with the severity of coronary atherosclerosis in aging patients, and the increase of circulating IGFBP1 levels with aging may be an adaptive response to counter HCAEC senescence through Akt signaling.

Orthostatic hypotension and the risk of atrial fibrillation and other cardiovascular diseases: An updated meta-analysis of prospective cohort studies

The relationships between orthostatic hypotension (OH) and some kinds of cardiovascular disease are inconsistent among studies. This updated meta-analysis was conducted in hopes of producing progress on this topic. A systematic database search was performed in electronic databases, including the Chinese Biomedical Database (CBM), PubMed, Web of Science, and the Cochrane Library. Summary hazard ratio (HR) estimates with 95% confidence intervals (CIs) were calculated by a random-effects model. Statistical heterogeneity was assessed with Cochran's Q test and the I2 statistic. From 1462 potentially eligible records, 15 studies met the inclusion criteria. Subjects with OH had a high risk of heart failure (HF) and atrial fibrillation (AF) (pooled HR 1.34, 95% CI 1.17-1.52, P < 0.001 and pooled HR 1.51, 95% CI 1.28-1.79, P < 0.001, respectively). This meta-analysis also showed significant associations between OH and the risks of developing coronary heart disease (CHD) (pooled HR 1.44, 95% CI 1.18-1.75, P < 0.001) and myocardial infarction (MI) (pooled HR 1.52, 95% CI 1.12-2.06, P = 0.008). Our study suggests that OH is positively associated with high risks of HF and AF. Moreover, it may be related to high risks of CHD and MI.

Angiopoietin-2 provides no incremental predictive value for the presence of obstructive coronary artery disease over N-terminal pro-brain natriuretic peptide

BACKGROUND

Using circulating biomarkers as a noninvasive method to assist the evaluation of coronary artery disease (CAD) is beneficial for reducing the unnecessary diagnostic cardiac catheterization. This study aimed to assess the predictive role of angiopoietin-2 (Ang-2) for the presence of obstructive coronary stenosis as compared with N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients with symptoms of CAD.

METHODS

The study enrolled 222 consecutive symptomatic patients who underwent elective diagnostic cardiac catheterization from July to December 2018. Blood samples were collected in the first morning after admission. The severity of coronary stenosis was assessed by coronary angiography. The obstructive CAD was defined as stenosis ≥50% of the left main coronary artery or stenosis ≥70% of a major epicardial vessel (left anterior descending artery, left circumflex artery and right coronary artery).

RESULTS

Patients with obstructive CAD (n = 120) had significantly higher levels of Ang-2 and NT-proBNP compared with those without. In multivariable regression analysis, only NT-proBNP levels were independently associated with Ang-2 levels. NT-proBNP was superior to Ang-2 as a predictor for the presence of obstructive CAD (NT-proBNP, area under curve [AUC] = 0.733, vs Ang-2, AUC = 0.626, P = 0.004). In multiple logistic regression analysis, NT-proBNP, but not Ang-2, was the independent predictor of obstructive CAD. The combination of Ang-2 with NT-proBNP did not provide the incremental value over NT-proBNP alone.

CONCLUSION

Serum Ang-2 levels are associated with NT-proBNP levels in patients suspected for CAD. NT-proBNP is superior to Ang-2 as a predictor for the presence of obstructive CAD. However, Ang-2 does not further increase diagnostic accuracy on top of NT-proBNP.

Performance of a clinical/proteomic panel to predict obstructive peripheral artery disease in patients with and without diabetes mellitus

Background

Patients with diabetes mellitus (DM) are at substantial risk of developing peripheral artery disease (PAD). We recently developed a clinical/proteomic panel to predict obstructive PAD. In this study, we compare the accuracy of this panel for the diagnosis of PAD in patients with and without DM.

Methods and results

The HART PAD panel consists of one clinical variable (history of hypertension) and concentrations of six biomarkers (midkine, kidney injury molecule-1, interleukin-23, follicle-stimulating hormone, angiopoietin-1 and eotaxin-1). In a prospective cohort of 354 patients undergoing peripheral and/or coronary angiography, performance of this diagnostic panel to detect ≥50% stenosis in at least one peripheral vessel was assessed in patients with (n=94) and without DM (n=260). The model had an area under the receiver operating characteristic curve (AUC) of 0.85 for obstructive PAD. At optimal cut-off, the model had 84% sensitivity, 75% specificity, positive predictive value (PPV) of 84% and negative predictive value (NPV) of 75% for detection of PAD among patients with DM, similar as in those without DM. In those with DM, partitioning the model into five levels resulted in a PPV of 95% and NPV of 100% in the highest and lowest levels, respectively. Abnormal scores were associated with a shorter time to revascularisation during 4.3 years of follow-up.

Conclusion

A clinical/biomarker model can predict with high accuracy the presence of PAD among patients with DM.

Trial registration number

NCT00842868.

TREML4 mRNA Expression and Polymorphisms in Blood Leukocytes are Associated with Atherosclerotic Lesion Extension in Coronary Artery Disease

Members of the triggering receptor expressed on myeloid cells (TREM) family are associated with atherosclerosis risk and progression. TREML4 is upregulated in the early phase of acute coronary syndrome. We investigated the relationship between the mRNA expression of 13 genes in blood leukocytes, TREML4 polymorphisms, and coronary artery lesion extension (Friesinger index) in patients with coronary artery disease (CAD) (n = 137). TREML4 rs2803495 (A > G) and rs2803496 (T > C) variants and leukocyte mRNA expression were analysed by qRT-PCR. TREML4 expression was higher in patients with major coronary artery lesions than in subjects without or with low and intermediate lesions (p < 0.05). However, TREML4 polymorphisms were not associated with coronary lesion extent. Presence of the rs2803495 G allele was not associated with increased TREML4 mRNA expression. Patients carrying the rs2803496 C allele (TC/CC genotypes) were more likely to express TREML4 mRNA than non-C allele carriers (allele C: OR 7.3, and 95% CI 1.9–27.5, p = 0.03). In conclusion, increased TREML4 mRNA expression in blood leukocytes is influenced by gene polymorphisms and is associated with more severe coronary artery lesions, suggesting its potential as a biomarker of the extent of coronary lesions in patients with CAD.

Predictive value of targeted proteomics for coronary plaque morphology in patients with suspected coronary artery disease

Background

Risk stratification is crucial to improve tailored therapy in patients with suspected coronary artery disease (CAD). This study investigated the ability of targeted proteomics to predict presence of high-risk plaque or absence of coronary atherosclerosis in patients with suspected CAD, defined by coronary computed tomography angiography (CCTA).

Methods

Patients with suspected CAD (n = 203) underwent CCTA. Plasma levels of 358 proteins were used to generate machine learning models for the presence of CCTA-defined high-risk plaques or complete absence of coronary atherosclerosis. Performance was tested against a clinical model containing generally available clinical characteristics and conventional biomarkers.

Findings

A total of 196 patients with analyzable protein levels (n = 332) was included for analysis. A subset of 35 proteins was identified predicting the presence of high-risk plaques. The developed machine learning model had fair diagnostic performance with an area under the curve (AUC) of 0·79 ± 0·01, outperforming prediction with generally available clinical characteristics (AUC = 0·65 ± 0·04, p < 0·05). Conversely, a different subset of 34 proteins was predictive for the absence of CAD (AUC = 0·85 ± 0·05), again outperforming prediction with generally available characteristics (AUC = 0·70 ± 0·04, p < 0·05).

Interpretation

Using machine learning models, trained on targeted proteomics, we defined two complementary protein signatures: one for identification of patients with high-risk plaques and one for identification of patients with absence of CAD. Both biomarker subsets were superior to generally available clinical characteristics and conventional biomarkers in predicting presence of high-risk plaque or absence of coronary atherosclerosis. These promising findings warrant external validation of the value of targeted proteomics to identify cardiovascular risk in outcome studies.

Fund

This study was supported by an unrestricted research grant from HeartFlow Inc. and partly supported by a European Research Area Network on Cardiovascular Diseases (ERA-CVD) grant (ERA CVD JTC2017, OPERATION). Funders had no influence on trial design, data evaluation, and interpretation.

Multiple biomarker panel to screen for severe aortic stenosis: results from the CASABLANCA study

Objective

Severe aortic valve stenosis (AS) develops via insidious processes and can be challenging to correctly diagnose. We sought to develop a circulating biomarker panel to identify patients with severe AS.

Methods

We enrolled study participants undergoing coronary or peripheral angiography for a variety of cardiovascular diseases at a single academic medical centre. A panel of 109 proteins were measured in blood obtained at the time of the procedure. Statistical learning methods were used to identify biomarkers and clinical parameters that associate with severe AS. A diagnostic model incorporating clinical and biomarker results was developed and evaluated using Monte Carlo cross-validation.

Results

Of 1244 subjects (age 66.4±11.5  years, 28.7% female), 80 (6.4%) had severe AS (defined as aortic valve area (AVA) <1.0  cm²). A final model included age, N-terminal pro-B-type natriuretic peptide, von Willebrand factor and fetuin-A. The model had good discrimination for severe AS (OR=5.9, 95% CI 3.5 to 10.1, p<0.001) with an area under the curve of 0.76 insample and 0.74 with cross-validation. A diagnostic score was generated. Higher prevalence of severe AS was noted in those with higher scores, such that 1.6% of those with a score of 1 had severe AS compared with 15.3% with a score of 5 (p<0.001), and score values were inversely correlated with AVA (r=−0.35; p<0.001). At optimal model cut-off, we found 76% sensitivity, 65% specificity, 13% positive predictive value and 98% negative predictive value.

Conclusions

We describe a novel, multiple biomarker approach for diagnostic evaluation of severe AS.

Trial registration number

NCT00842868.

A Simple Modified Framingham Scoring System to Predict Obstructive Coronary Artery Disease

Development of simple non-invasive risk prediction model would help in early prediction of coronary artery disease (CAD) reducing the burden on public health. This paper demonstrates a risk prediction scoring system to predict obstructive coronary artery disease (OCAD) in CAD patients. A total of 13,082 patients, referred for coronary angiography (CAG) in TRUST trial, were included in the development of a multivariable diagnostic prediction model. External validation of the model used 1009 patients from PRECOMIN study. The occurrence of OCAD was observed in 73.1% and 75.1% patients in TRUST (development) and PRECOMIN study (validation) cohorts, respectively. Good discrimination and calibration were obtained in both development and validation datasets (C-statistics 0.686 and 0.677; Hosmer-Lemeshow χ² = 5.19, p = 0.74 and χ² = 8.60, p = 0.38, respectively). The simple risk prediction model and risk scoring system developed on the basis of routine clinical variables showed good performance for estimation of OCAD in relative high-risk patients with suspected CAD.

Proteomic Discovery and Validation of the Confounding Effect of Heparin Administration on the Analysis of Candidate Cardiovascular Biomarkers

BACKGROUND

Several plasma proteins have been suggested as markers for a variety of cardiovascular conditions but fail to qualify in independent patient cohorts. This may relate to interference of medication on plasma protein concentrations. We used proteomics to identify plasma proteins that changed in concentration with heparin administration and therefore potentially may confound their evaluation as biomarkers in situations in which heparin is used.

METHODS

We used a proteomic approach based on isobaric tagging and nano-LC-MS/MS analysis to quantify several hundred proteins in a discovery study in which individual plasma samples from 9 patients at intravascular ultrasound follow-up 12 months after an acute myocardial infarction before heparin administration and 2, 15, and 60 min after heparin administration; we validated our findings in 500 individual plasma samples obtained at admission from patients with suspected ST segment elevation myocardial infarction (STEMI), of whom 363 were treated with heparin before admission.

RESULTS

In the discovery study, 25 of 653 identified plasma proteins displayed a changed concentration after heparin administration (Bonferroni-corrected P value at P &lt; 7.66 × 10−5). Fourteen of the proteins changed significantly among heparin-treated patients in the validation study (nominal significance level of P &lt; 6.92 × 10−5). Among heparin-affected proteins in both the discovery study and the validation study were midkine, spondin 1, secreted frizzled-like protein 1, lipoprotein lipase, and follistatin, all previously associated with STEMI.

CONCLUSIONS

Medications such as heparin administration given before blood sampling may confound biomarker discovery and should be carefully considered in such studies.

A clinical and proteomics approach to predict the presence of obstructive peripheral arterial disease: From the Catheter Sampled Blood Archive in Cardiovascular Diseases (CASABLANCA) Study

BACKGROUND

Peripheral arterial disease (PAD) is a global health problem that is frequently underdiagnosed and undertreated. Noninvasive tools to predict the presence and severity of PAD have limitations including inaccuracy, cost, or need for intravenous contrast and ionizing radiation.

HYPOTHESIS

A clinical/biomarker score may offer an attractive alternative diagnostic method for PAD.

METHODS

In a prospective cohort of 354 patients referred for diagnostic peripheral and/or coronary angiography, predictors of ≥50% stenosis in ≥1 peripheral vessel (carotid/subclavian, renal, or lower extremity arteries) were identified from >50 clinical variables and 109 biomarkers. Machine learning identified variables predictive of obstructive PAD; a score derived from the final model was developed.

RESULTS

The score consisted of 1 clinical variable (history of hypertension) and 6 biomarkers (midkine, kidney injury molecule-1, interleukin-23, follicle-stimulating hormone, angiopoietin-1, and eotaxin-1). The model had an in-sample area under the receiver operating characteristic curve of 0.85 for obstructive PAD and a cross-validated area under the curve of 0.84; higher scores were associated with greater severity of angiographic stenosis. At optimal cutoff, the score had 65% sensitivity, 88% specificity, 76% positive predictive value (PPV), and 81% negative predictive value (NPV) for obstructive PAD and performed consistently across vascular territories. Partitioning the score into 5 levels resulted in a PPV of 86% and NPV of 98% in the highest and lowest levels, respectively. Elevated score was associated with shorter time to revascularization during 4.3 years of follow-up.

CONCLUSIONS

A clinical/biomarker score demonstrates high accuracy for predicting the presence of PAD.

High-Sensitivity Troponin I and Coronary Computed Tomography in Symptomatic Outpatients With Suspected CAD: Insights From the PROMISE Trial

OBJECTIVES

The goal of this study was to examine associations between concentrations of high-sensitivity troponin I (hsTnI) (measured by using a single-molecule counting method) and obstructive coronary artery disease (CAD) in 1,844 stable, symptomatic outpatients with suspected CAD randomized to undergo coronary computed tomography angiography (CTA) in the PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) trial.

BACKGROUND

Elevated concentrations of hsTnI are associated with CAD in patients with myocardial infarction. The meaning of hsTnI concentrations in stable symptomatic outpatients is not well understood.

METHODS

Clinical characteristics and CTA results (including coronary artery calcium [CAC] scores) were expressed across hsTnI quartiles. Determinants of hsTnI concentration were identified. Multivariable logistic regression identified independent predictors of obstructive CAD₅₀ (≥50% stenosis in any vessel) and CAD₇₀ (≥70% stenosis or ≥50% left main).

RESULTS

The median hsTnI concentration was 1.5 ng/l; nearly all (98.5%) subjects had measurable hsTnI, and 6.1% had concentrations ≥99th percentile concentration for this assay (6 ng/l). Higher CAC scores, as well as more prevalent and diffuse CAD, was seen in upper hsTnI quartiles (all p < 0.001). Independent predictors of hsTnI concentrations included age, sex, and CAC score (all p < 0.05). After adjusting for demographic and clinical characteristics, log-transformed hsTnI concentrations were associated with obstructive CAD₅₀ (odds ratio: 1.15 per interquartile range; p = 0.02) and CAD₇₀ (odds ratio: 1.25 per interquartile range; p = 0.001).

CONCLUSIONS

In stable symptomatic outpatients undergoing nonemergent coronary CTA for the diagnosis of suspected CAD, higher concentrations of hsTnI were associated with increasing presence and severity of coronary atherosclerosis. (Prospective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550).

Biomarkers in stable coronary artery disease

Coronary artery disease (CAD) remains a significant cause of morbidity and mortality around the world. Patients with stable CAD can have an unpredictable clinical trajectory; thus, additional tools to prognosticate risk in this cohort are warranted. In recent years, a wide range of biomarkers has been recognized for their diagnostic capabilities in patients with stable CAD, identifying those with obstructive disease who may require more intensive preventive therapies or even consideration of percutaneous coronary intervention in some circumstances. In addition, a multiple-biomarker approach may identify stable CAD patients at highest risk for future major adverse cardiac events. Thus, randomized controlled trials to assess biomarker-guided preventive therapy in this cohort appear warranted.

A simple prediction model to estimate obstructive coronary artery disease

BACKGROUND

A simple noninvasive model to predict obstructive coronary artery disease (OCAD) may promote risk stratification and reduce the burden of coronary artery disease (CAD). This study aimed to develop pre-procedural, noninvasive prediction models that better estimate the probability of OCAD among patients with suspected CAD undergoing elective coronary angiography (CAG).

METHODS

We included 1262 patients, who had reliable Framingham risk variable data, in a cohort without known CAD from a prospective registry of patients referred for elective CAG. We investigated pre-procedural OCAD (≥50% stenosis in at least one major coronary vessel based on CAG) predictors.

RESULTS

A total of 945 (74.9%) participants had OCAD. The final modified Framingham scoring (MFS) model consisted of anemia, high-sensitivity C-reactive protein, left ventricular ejection fraction, and five Framingham factors (age, sex, total and high-density lipoprotein cholesterol, and hypertension). Bootstrap method (1000 times) revealed that the model demonstrated a good discriminative power (c statistic, 0.729 ± 0.0225; 95% CI, 0.69-0.77). MFS provided adequate goodness of fit (P = 0.43) and showed better performance than Framingham score (c statistic, 0.703 vs. 0.521; P < 0.001) in predicting OCAD, thereby identifying patients with high risks for OCAD (risk score ≥ 27) with ≥70% predictive value in 68.8% of subjects (range, 37.2-87.3% for low [≤17] and very high [≥41] risk scores).

CONCLUSION

Our data suggested that the simple MFS risk stratification tool, which is available in most primary-level clinics, showed good performance in estimating the probability of OCAD in relatively stable patients with suspected CAD; nevertheless, further validation is needed.

Relationships of kidney injury molecule-1 with renal function and cardiovascular risk factors in the general population

BACKGROUND

Kidney injury molecule-1 (KIM-1) has been associated with kidney damage in patients with preexisting renal disease. However, little is known about the relationships of KIM-1 with renal function and cardiovascular risk factors in healthy individuals from the general population.

METHODS

Healthy individuals aged 25-41years were enrolled in a population-based study. Main exclusion criteria were a BMI >35kg/m², preexisting kidney disease or established cardiovascular disease. KIM-1 was measured from frozen plasma samples using a high-sensitivity assay. Multivariable linear regression models were constructed to assess the relationships of KIM-1 with renal function and various cardiovascular risk factors.

RESULTS

We included 2060 individuals (47% men, median (interquartile range) age: 37 (31-40) years) in this analysis. Median KIM-1 levels were 82.5 (IQR 59.4-112.7) pg/ml. We found no significant relationship of KIM-1 with creatinine (adjusted β-coefficient (95% confidence interval) 0.0005 (-0.002; 0.003), p=0.61) and cystatin C (-0.02 (-0.21; 0.17), p=0.84). There were significant linear relationships of log-transformed KIM-1 with systolic blood pressure (adjusted β-coefficient (95% confidence interval) 0.07 (0.04; 0.09), p<0.0001), diastolic blood pressure (0.04 (0.02; 0.07), p=0.001), low-density lipoprotein cholesterol (0.09 (0.06; 0.11), p<0.0001), high-density lipoprotein cholesterol (0.07 (0.05; 0.1), p<0.0001), high-sensitivity C-reactive protein (0.05 (0.03; 0.07), p<0.0001), age (0.09 (0.07; 0.11), p<0.0001), BMI (0.04 (0.01; 0.06), p=0.005) and current smoking (0.12 (0.07; 0.17), p<0.0001).

CONCLUSION

Among healthy adults from the general population, plasma levels of KIM-1 were not associated with renal function but were independently related to multiple cardiovascular risk factors.

Midkine Promotes Atherosclerotic Plaque Formation Through Its Pro-Inflammatory, Angiogenic and Anti-Apoptotic Functions in Apolipoprotein E-Knockout Mice

BACKGROUND

A recent study suggested that midkine (MK), a heparin-binding growth factor, is associated with atherosclerosis progression in patients with artery disease. It has previously been reported that MK plays a critical role in neointima formation in a restenosis model, whereas the role of MK in the development of atherosclerosis has not been investigated. The present study assessed the effect of MK administration on the process of atherosclerotic plaque formation in apolipoprotein E-knockout (ApoE^-/-) mice.Methods and Results:Using an osmotic pump, human recombinant MK protein was intraperitoneally administered for 12 weeks in C57BL/6 ApoE^-/-(ApoE^-/--MK) and ApoE^+/+mice fed a high-fat diet. Saline was administered to the control groups of ApoE^-/-(ApoE^-/--saline) and ApoE^+/+mice. The atherosclerotic lesion areas in longitudinal aortic sections were significantly larger in ApoE^-/--MK mice than in ApoE^-/--saline mice. The aortic mRNA levels of pro-inflammatory and angiogenic factors, and the percentage of macrophages in aortic root lesions, were significantly higher in ApoE^-/--MK mice than in ApoE^-/--saline mice, whereas the percentage of apoptotic cells was significantly lower in ApoE^-/--MK mice than in ApoE^-/--saline mice.

CONCLUSIONS

The systemic administration of MK in ApoE^-/-mice promoted atherosclerotic plaque formation through pro-inflammatory, angiogenic, and anti-apoptotic effects. MK may serve as a potential therapeutic target for the prevention of atherosclerosis under atherogenic conditions.