State of the Art: Blood Biomarkers for Risk Stratification in Patients with Stable Ischemic Heart Disease

Multifractal foundations of biomarker discovery for heart disease and stroke

Any reliable biomarker has to be specific, generalizable, and reproducible across individuals and contexts. The exact values of such a biomarker must represent similar health states in different individuals and at different times within the same individual to result in the minimum possible false-positive and false-negative rates. The application of standard cut-off points and risk scores across populations hinges upon the assumption of such generalizability. Such generalizability, in turn, hinges upon this condition that the phenomenon investigated by current statistical methods is ergodic, i.e., its statistical measures converge over individuals and time within the finite limit of observations. However, emerging evidence indicates that biological processes abound with nonergodicity, threatening this generalizability. Here, we present a solution for how to make generalizable inferences by deriving ergodic descriptions of nonergodic phenomena. For this aim, we proposed capturing the origin of ergodicity-breaking in many biological processes: cascade dynamics. To assess our hypotheses, we embraced the challenge of identifying reliable biomarkers for heart disease and stroke, which, despite being the leading cause of death worldwide and decades of research, lacks reliable biomarkers and risk stratification tools. We showed that raw R-R interval data and its common descriptors based on mean and variance are nonergodic and non-specific. On the other hand, the cascade-dynamical descriptors, the Hurst exponent encoding linear temporal correlations, and multifractal nonlinearity encoding nonlinear interactions across scales described the nonergodic heart rate variability more ergodically and were specific. This study inaugurates applying the critical concept of ergodicity in discovering and applying digital biomarkers of health and disease.

Differences between high-sensitivity cardiac troponin T and I in stable populations: underlying causes and clinical implications

OBJECTIVES

Measurement of high-sensitivity (hs) cardiac troponin (cTn) T and I is widely studied for cardiac assessment of stable populations. Recent data suggest clinical and prognostic discrepancies between both hs-cTn. We aimed at reviewing published studies with respect to underlying causes and clinical implications.

CONTENT

We summarized current evidence on release and clearance mechanisms of cTnT and I, and on preanalytical and assay-related issues potentially portending to differences in measured concentrations. We also performed a systematic review of outcome studies comparing both hs-cTn in the general population, patients with congestive heart failure, stable coronary artery disease and atrial fibrillation.

SUMMARY AND OUTLOOK

For the interpretation of concentrations of hs-cTnT, stronger association with renal dysfunction compared to hs-cTnI should be considered. Hs-cTnT also appears to be a stronger indicator of general cardiovascular morbidity and all-cause mortality. Hs-cTnI concentrations tend to be more sensitive to coronary artery disease and ischemic outcomes. These findings apparently reflect variations in the mechanisms of cardiac affections resulting in cTn release. Whether these differences are of clinically relevance remains to be elucidated. However, having the option of choosing between either hs-cTn might represent an option for framing individualized cardiac assessment in the future.

Association of GDF-15, hs-cTnT and NT-proBNP with coronary artery disease in patients undergoing elective angiography

Aim: This study investigated the association between plasma levels of GDF-15, hs-cTnT and NT-proBNP and the presence of coronary artery disease (CAD) in stable patients referred for elective coronary angiography. Methods: The outcome of CAD was defined as an ordinal variable with 3 levels. The association between each biomarker and the outcome was tested using the Winell and Lindbäck method. Results: In unadjusted analysis of 252 patients, GDF-15 and hs-cTnT were associated with the presence and extent of CAD. In multivariate regression analysis including traditional risk factors, this association was no longer significant. Conclusion: NT-proBNP, GDF-15 and hs-cTnT plasma levels do not seem to improve the predictive ability of traditional risk factors for CAD in stable patients referred for coronary angiography.

High fibrinogen-to-albumin ratio with type 2 diabetes mellitus is associated with poor prognosis in patients undergoing percutaneous coronary intervention: 5-year findings from a large cohort

BACKGROUND

Inflammation plays a crucial role in coronary atherosclerosis progression, and growing evidence has demonstrated that the fibrinogen-to-albumin ratio (FAR), as a novel inflammation biomarker, is associated with the severity of coronary artery disease (CAD). However, the long-term risk of cardiovascular events remains indistinct in patients with different level of FAR and different glycemic metabolism status. This study was to assess 5-year clinical outcomes of diabetic and non-diabetic patients who underwent percutaneous coronary intervention (PCI) with different level of FAR.

METHODS

We consecutively enrolled 10,724 patients with CAD hospitalized for PCI and followed up for the major adverse cardiac and cerebrovascular events (MACCE) covering all-cause mortality, cardiac mortality, non-fatal myocardial infarction, non-fatal ischemic stroke, and unplanned coronary revascularization. FAR was computed using the following formula: Fibrinogen (g/L)/Albumin (g/L). According to the optimal cut-off value of FAR for MACCE prediction, patients were divided into higher level of FAR (FAR-H) and lower level of FAR (FAR-L) subgroups, and were further categorized into four groups as FAR-H with DM and non-DM, and FAR-L with DM and non-DM.

RESULTS

5298 patients (58.36 ± 10.36 years, 77.7% male) were ultimately enrolled in the present study. A total of 1099 (20.7%) MACCEs were documented during the 5-year follow-up. The optimal cut-off value of FAR was 0.0783 by the surv_cutpoint function. Compared to ones with FAR-H and DM, patients with FAR-L and non-DM, FAR-H and non-DM, FAR-L and DM had decreased risk of MACCEs [adjusted hazard ratio (HR): 0.75, 95% confidence interval (CI) 0.64-0.89, P = 0.001; HR: 0.78, 95% CI 0.66-0.93, P = 0.006; HR: 0.81, 95% CI 0.68-0.97, P = 0.019; respectively]. Notably, non-diabetic patients with lower level of FAR also had lower all-cause mortality and cardiac mortality risk than those in the FAR-H/DM group (HR: 0.41, 95% CI 0.27-0.63, P < 0.001; HR: 0.30, 95% CI 0.17-0.53, P < 0.001; respectively). Multivariate Cox proportional hazards regression analysis also indicated the highest risk of MACCEs in patients with FAR-H and DM than others (P for trend = 0.005). In addition, post-hoc analysis revealed consistent effects on 5-year MACCE across various subgroups.

CONCLUSION

In this real-world cohort study, higher level of FAR combined with DM was associated with worse 5-year outcomes among patients with CAD undergoing PCI. The level of FAR may help to identify high-risk individuals in this specific population, where more precise risk assessment should be performed.

Biomarkers of non-communicable chronic disease: an update on contemporary methods

Chronic diseases constitute a major global burden with significant impact on health systems, economies, and quality of life. Chronic diseases include a broad range of diseases that can be communicable or non-communicable. Chronic diseases are often associated with modifications of normal physiological levels of various analytes that are routinely measured in serum and other body fluids, as well as pathological findings, such as chronic inflammation, oxidative stress, and mitochondrial dysfunction. Identification of at-risk populations, early diagnosis, and prediction of prognosis play a major role in preventing or reducing the burden of chronic diseases. Biomarkers are tools that are used by health professionals to aid in the identification and management of chronic diseases. Biomarkers can be diagnostic, predictive, or prognostic. Several individual or grouped biomarkers have been used successfully in the diagnosis and prediction of certain chronic diseases, however, it is generally accepted that a more sophisticated approach to link and interpret various biomarkers involved in chronic disease is necessary to improve our current procedures. In order to ensure a comprehensive and unbiased coverage of the literature, first a primary frame of the manuscript (title, headings and subheadings) was drafted by the authors working on this paper. Second, based on the components drafted in the preliminary skeleton a comprehensive search of the literature was performed using the PubMed and Google Scholar search engines. Multiple keywords related to the topic were used. Out of screened papers, only 190 papers, which are the most relevant, and recent articles were selected to cover the topic in relation to etiological mechanisms of different chronic diseases, the most recently used biomarkers of chronic diseases and finally the advances in the applications of multivariate biomarkers of chronic diseases as statistical and clinically applied tool for the early diagnosis of chronic diseases was discussed. Recently, multivariate biomarkers analysis approach has been employed with promising prospect. A brief discussion of the multivariate approach for the early diagnosis of the most common chronic diseases was highlighted in this review. The use of diagnostic algorithms might show the way for novel criteria and enhanced diagnostic effectiveness inpatients with one or numerous non-communicable chronic diseases. The search for new relevant biomarkers for the better diagnosis of patients with non-communicable chronic diseases according to the risk of progression, sickness, and fatality is ongoing. It is important to determine whether the newly identified biomarkers are purely associations or real biomarkers of underlying pathophysiological processes. Use of multivariate analysis could be of great importance in this regard.

Antioxidant/Pro-Oxidant Actions of Polyphenols From Grapevine and Wine By-Products-Base for Complementary Therapy in Ischemic Heart Diseases

Grape pomace and grape seeds, by-products of the wine industry, and grapevine cane resulting from grapevine pruning are cheap matrices containing important amounts of polyphenols. While there is a continuous need of introducing new ways of these by-products valorization, we propose their use as a source of bioactive polyphenols for complementary therapy in ischemic heart diseases. As oxidative stress plays an important role in these diseases, by their antioxidant/pro-oxidant properties, these compounds, mainly flavan-3-ols, procyanidins, and resveratrol may counteract the damage of the oxidative stress. For instance, to some extent, the grape seed extract, considered as an antioxidant nutritive supplement, may have pro-oxidant activity as well, depending on dose, duration of administration, and other dietary components. In vitro studies confirm that the antioxidant activity of this extract might be mediated by pro-oxidant o-quinones and oxidation products of the polyphenols from grape and winery byproducts, indicating that quinones, as oxidation products, are involved in the modulation of the antioxidant/pro-oxidant balance at the cellular level in the case of catechin-type compounds, in the absence or presence of oxidative stress inducers. In vivo, studies indicate that a grape pomace-rich diet results in a significant increase of the total antioxidant status in the plasma, liver, spleen, and kidneys. Also, the administration of grape pomace shows antioxidant activity with positive effects on health. In this context, the present review aims to present the most recent research focused on the antioxidant/pro-oxidant actions of the bioactive polyphenols from grapevine and wine byproducts, in conditions of ischemic heart diseases as assessed in vitro or in vivo.

Circulating Biomarkers for Cardiovascular Disease Risk Prediction in Patients With Cardiovascular Disease

Cardiovascular disease (CVD) is the leading cause of death globally. Risk assessment is crucial for identifying at-risk individuals who require immediate attention as well as to guide the intensity of medical therapy to reduce subsequent risk of CVD. In the past decade, many risk prediction models have been proposed to estimate the risk of developing CVD. However, in patients with a history of CVD, the current models that based on traditional risk factors provide limited power in predicting recurrent cardiovascular events. Several biomarkers from different pathophysiological pathways have been identified to predict cardiovascular events, and the incorporation of biomarkers into risk assessment may contribute to enhance risk stratification in secondary prevention. This review focuses on biomarkers related to cardiovascular and metabolic diseases, including B-type natriuretic peptide, high-sensitivity cardiac troponin I, adiponectin, adipocyte fatty acid-binding protein, heart-type fatty acid-binding protein, lipocalin-2, fibroblast growth factor 19 and 21, retinol-binding protein 4, plasminogen activator inhibitor-1, 25-hydroxyvitamin D, and proprotein convertase subtilisin/kexin type 9, and discusses the potential utility of these biomarkers in cardiovascular risk prediction among patients with CVD. Many of these biomarkers have shown promise in improving risk prediction of CVD. Further research is needed to assess the validity of biomarker and whether the strategy for incorporating biomarker into clinical practice may help to optimize decision-making and therapeutic management.

Elevated serum lipoprotein(a) is significantly associated with angiographic progression of coronary artery disease

Background

Lipoprotein(a)[Lp(a)] has been considered as an independent risk factor for coronary artery disease (CAD). The present study aimed to evaluate the association between baseline serum Lp(a) and CAD progression determined by angiographic score.

Methods

A total of 814 patients who had undergone two or more coronary computed tomography angiography at least 6 months apart were consecutively enrolled and the coronary severity was determined by the Gensini score system. Patients were stratified into two groups according to Lp(a)>300 mg/L and Lp(a) ≤ 300 mg/L or classified as “progressors” and “non‐progressors” based on the Gensini score rate of change per year. The association of continuous Lp(a) and Lp(a)>300 mg/L with CAD progression were respectively assessed by logistic regression analysis. Moreover, further evaluation of those association was performed in subgroups of the study population.

Results

Patients in the “progressors” group had significant higher Lp(a) levels. Furthermore, the multivariate logistic regression analysis showed that elevated Lp(a) (odds ratio [OR]: 1.451, 95% confidence interval [CI]: 1.177–1.789, p<.001) and Lp(a)>300 mg/L (OR:1.642, 95% CI:1.018–2.649, p = .042) were positively associated with CAD progression after adjusting for confounding factors. In addition, those relation seemed to be more prominent in subjects with lower body mass index (OR: 1.880, 95% CI: 1.224–2.888, p for interaction = .060).

Conclusions

Elevated baseline serum Lp(a) is positively and independently associated with angiographic progression of CAD, particularly in participants with relatively low body mass index. Therefore, Lp(a) could be a potent risk factor for CAD progression, assisting in early risk stratification in cardiovascular patients.

Diagnosis and Management of Stable Angina: A Review

IMPORTANCE

Nearly 10 million US adults experience stable angina, which occurs when myocardial oxygen supply does not meet demand, resulting in myocardial ischemia. Stable angina is associated with an average annual risk of 3% to 4% for myocardial infarction or death. Diagnostic tests and medical therapies for stable angina have evolved over the last decade with a better understanding of the optimal use of coronary revascularization.

OBSERVATIONS

Coronary computed tomographic angiography is a first-line diagnostic test in the evaluation of patients with stable angina due to higher sensitivity and comparable specificity compared with imaging-based stress testing. Moreover, coronary computed tomographic angiography allows detection of nonobstructive atherosclerosis that would not be identified with other noninvasive imaging modalities, improving risk assessment and potentially triggering more appropriate allocation of preventive therapies. Novel therapies treating lipids (proprotein convertase subtilisin/kexin type 9 inhibitors, ezetimibe, and icosapent ethyl) and type 2 diabetes (sodium-glucose cotransporter 2 inhibitors, glucagon-like peptide 1 receptor agonists) have improved cardiovascular outcomes in patients with stable ischemic heart disease when added to usual care. Randomized clinical trials showed no improvement in the rates of mortality or myocardial infarction with revascularization (largely by percutaneous coronary intervention) compared with optimal medical therapy alone, even in the setting of moderate to severe ischemia. In contrast, revascularization provides a meaningful benefit on angina and quality of life compared with antianginal therapies. Measures of the effect of angina on a patient's quality of life should be integrated into the clinic encounter to assist with the decision to proceed with revascularization.

CONCLUSIONS AND RELEVANCE

For patients with stable angina, emphasis should be placed on optimizing lifestyle factors and preventive medications such as lipid-lowering and antiplatelet agents to reduce the risk for cardiovascular events and death. Antianginal medications, such as β-blockers, nitrates, or calcium channel blockers, should be initiated to improve angina symptoms. Revascularization with percutaneous coronary intervention should be reserved for patients in whom angina symptoms negatively influence quality of life, generally after a trial of antianginal medical therapy. Shared decision-making with an informed patient is important for effective treatment of stable angina.

Association between vitamin D deficiency and serum Homocysteine levels and its relationship with coronary artery disease

Homocysteine (Hcy) elevation and vitamin D deficiency have emerged as potential markers of coronary artery disease (CAD). However, even tough hypovitaminosis D has been suggested to interfere with Hcy catabolism, no study has so far addressed the interaction of vitamin D and Hcy and their impact on CAD, that was the aim of present study. A cohort of consecutive patients undergoing coronary angiography in a single center were included and analyzed within the year 2019. Significant CAD was defined as at least 1 vessel stenosis > 50%, while severe CAD as left main and/or three-vessel disease. Hcy and vitamin D levels were assesssed at admission. We included 3150 patients undergoing coronary angiography at our centre, who were divided according to the quartiles values of vitamin D. Patients with lower levels of Vitamin D displayed a higher cardiovascular risk profile and a higher prevalence of CAD. We observed an inverse linear relationship between lower levels of vitamin D and higher Hcy (r = − 0.092, p < 0.001) and a higher prevalence of hyperhomocysteinemia in patients with lower quartiles values of vitamin D (p < 0.001). By forward conditional regression model, low vitamin D appeared as independent predictors of Homocysteine levels above the median (OR[95%CI] = 1.79[1.37–2.33], p < 0.001). In addition, patients with low vitamin D (below the median) and increased Hcy displayed a non-significantly higher rate of CAD (81% vs 77.7%, p = 0.13, adjusted OR[95%CI] = 1.16[0.88–1.54], p = 0.29) but a significant increase in the rate of severe left main/3-vessel CAD (37.4% vs 30.5%, p = 0.005, adjusted OR[95%CI] = 1.29[1.02–1.67], p = 0.04). Among patients with vitamin D levels above the median, Hcy levels did not impact on the prevalence and extent of CAD (77.7 vs 77.2%, p = 0.81, adjusted OR[95%CI] = 0.94[0.73–1.20], p = 0.60 for CAD and 31.8% vs 27.7%, p = 0.08, adjusted OR[95%CI] = 0.97[0.75–1.25], p = 0.81 for severe left main/3-vessel CAD). No significant interaction between Hcy and vitamin D with CAD or severe CAD was observed. The present study shows an independent inverse linear relationship between vitamin D and Hcy values. Moreover, the association of Hcy with the extent of CAD was significant only among patients with hypovitaminosis D, and not in the cohort of subjects with vitamin D levels above the median, suggesting that a normal vitamin D status can prevent the deleterious effects of hyperhomocysteinemia on coronary atherosclerosis, a hypothesis that certainly needs further confirmation in larger randomized trials.

Plasma proteins associated with cardiovascular death in patients with chronic coronary heart disease: A retrospective study

BACKGROUND

Circulating biomarkers are associated with the development of coronary heart disease (CHD) and its complications by reflecting pathophysiological pathways and/or organ dysfunction. We explored the associations between 157 cardiovascular (CV) and inflammatory biomarkers and CV death using proximity extension assays (PEA) in patients with chronic CHD.

METHODS AND FINDINGS

The derivation cohort consisted of 605 cases with CV death and 2,788 randomly selected non-cases during 3-5 years follow-up included in the STabilization of Atherosclerotic plaque By Initiation of darapLadIb TherapY (STABILITY) trial between 2008 and 2010. The replication cohort consisted of 245 cases and 1,042 non-cases during 12 years follow-up included in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study between 1997 and 2000. Biomarker levels were measured with conventional immunoassays and/or with the OLINK PEA panels CVD I and Inflammation. Associations with CV death were evaluated by Random Survival Forest (RF) and Cox regression analyses. Both cohorts had the same median age (65 years) and 20% smokers, while there were slight differences in male sex (82% and 76%), hypertension (70% and 78%), and diabetes (39% and 30%) in the respective STABILITY and LURIC cohorts. The analyses identified 18 biomarkers with confirmed independent association with CV death by Boruta analyses and statistical significance (all p < 0.0001) by Cox regression when adjusted for clinical characteristics in both cohorts. Most prognostic information was carried by N-terminal prohormone of brain natriuretic peptide (NTproBNP), hazard ratio (HR for 1 standard deviation [SD] increase of the log scale of the distribution of the biomarker in the replication cohort) 2.079 (95% confidence interval [CI] 1.799-2.402), and high-sensitivity troponin T (cTnT-hs) HR 1.715 (95% CI 1.491-1.973). The other proteins with independent associations were growth differentiation factor 15 (GDF-15) HR 1.728 (95% CI 1.527-1.955), transmembrane immunoglobulin and mucin domain protein (TIM-1) HR 1.555 (95% CI 1.362-1.775), renin HR 1.501 (95% CI 1.305-1.727), osteoprotegerin (OPG) HR 1.488 (95% CI 1.297-1.708), soluble suppression of tumorigenesis 2 protein (sST2) HR 1.478 (95% CI 1.307-1.672), cystatin-C (Cys-C) HR 1.370 (95% CI 1.243-1.510), tumor necrosis factor-related apoptosis-inducing ligand receptor 2 (TRAIL-R2) HR 1.205 (95% CI 1.131-1.285), carbohydrate antigen 125 (CA-125) HR 1.347 (95% CI 1.226-1.479), brain natriuretic peptide (BNP) HR 1.399 (95% CI 1.255-1.561), interleukin 6 (IL-6) HR 1.478 (95% CI 1.316-1.659), hepatocyte growth factor (HGF) HR 1.259 (95% CI 1.134-1.396), spondin-1 HR 1.295 (95% CI 1.156-1.450), fibroblast growth factor 23 (FGF-23) HR 1.349 (95% CI 1.237-1.472), chitinase-3 like protein 1 (CHI3L1) HR 1.284 (95% CI 1.129-1.461), tumor necrosis factor receptor 1 (TNF-R1) HR 1.486 (95% CI 1.307-1.689), and adrenomedullin (AM) HR 1.750 (95% CI 1.490-2.056). The study is limited by the differences in design, size, and length of follow-up of the 2 studies and the lack of results from coronary angiograms and follow-up of nonfatal events.

CONCLUSIONS

Profiles of levels of multiple plasma proteins might be useful for the identification of different pathophysiological pathways associated with an increased risk of CV death in patients with chronic CHD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00799903.

Advances in Cardiovascular Biomarker Discovery

Cardiovascular diseases are the leading causes of mortality worldwide. Among them, hypertension and its pathological complications pose a major risk for the development of other cardiovascular diseases, including heart failure and stroke. Identifying novel and early stage biomarkers of hypertension and other cardiovascular diseases is of paramount importance in predicting and preventing the major morbidity and mortality associated with these diseases. Biomarkers of such diseases or predisposition to their development are identified by changes in a specific indicator’s expression between healthy individuals and patients. These include changes in protein and microRNA (miRNA) levels. Protein profiling using mass spectrometry and miRNA screening utilizing microarray and sequencing have facilitated the discovery of proteins and miRNA as biomarker candidates. In this review, we summarized some of the different, promising early stage protein and miRNA biomarker candidates as well as the currently used biomarkers for hypertension and other cardiovascular diseases. Although a number of promising markers have been identified, it is unlikely that a single biomarker will unambiguously aid in the classification of these diseases. A multi-marker panel-strategy appears useful and promising for classifying and refining risk stratification among patients with cardiovascular disease.

Prognostic utility of lipoprotein(a) combined with fibrinogen in patients with stable coronary artery disease: a prospective, large cohort study

Background

Elevated lipoprotein(a) [Lp(a)] and fibrinogen (Fib) are both associated with coronary artery disease (CAD). The atherogenicity of Lp(a) can be partly due to the potentially antifibrinolytic categories. We hypothesize that patients with higher Lp(a) and Fib may have worse outcomes.

Methods

In this prospective study, we consecutively enrolled 8,417 Chinese patients with stable CAD from March 2011 to March 2017. All subjects were divided into 9 groups according to Lp(a) (Lp(a)-Low, Lp(a)-Medium, Lp(a)-High) and Fib levels (Fib-Low, Fib-Medium, Fib-High) and followed up for CVEs, including nonfatal acute myocardial infarction, stroke, and cardiovascular mortality. Kaplan–Meier, Cox regression and C-statistic analyses were performed.

Results

During a median of 37.1 months’ follow-up, 395 (4.7%) CVEs occurred. The occurrence of CVEs increased by Lp(a) (3.5 vs. 5.3 vs. 5.6%, p = 0.001) and Fib (4.0 vs. 4.4 vs. 6.1%, p < 0.001) categories. When further classified into 9 groups by Lp(a) and Fib levels, the CVEs were highest in the 9th (Lp(a)-High and Fib-High) compared with the 1st (Lp(a)-Low and Fib-Low) group (7.2 vs. 3.3%, p < 0.001). The highest risk of subsequent CVEs was found in the 9^th group (HR_adjusted 2.656, 95% CI 1.628–4.333, p < 0.001), which was more significant than Lp(a)-High (HR_adjusted 1.786, 95% CI 1.315–2.426, p < 0.001) or Fib-High (HR_adjusted 1.558, 95% CI 1.162–2.089, p = 0.003) group. Moreover, adding the combined Lp(a) and Fib increased the C-statistic by 0.013.

Conclusion

Combining Fib and Lp(a) enhance the prognostic value for incident CVEs beyond Lp(a) or Fib alone.

Imaging tools for assessment of myocardial fibrosis in humans: the need for greater detail

Myocardial fibrosis is recognized as a key pathological process in the development of cardiac disease and a target for future therapeutics. Despite this recognition, the assessment of fibrosis is not a part of routine clinical practice. This is primarily due to the difficulties in obtaining an accurate assessment of fibrosis non-invasively. Moreover, there is a clear discrepancy between the understandings of myocardial fibrosis clinically where fibrosis is predominately studied with comparatively low-resolution medical imaging technologies like MRI compared with the basic science laboratories where fibrosis can be visualized invasively with high resolution using molecularly specific fluorescence microscopes at the microscopic and nanoscopic scales. In this article, we will first review current medical imaging technologies for assessing fibrosis including echo and MRI. We will then highlight the need for greater microscopic and nanoscopic analysis of human tissue and how this can be addressed through greater utilization of human tissue available through endomyocardial biopsies and cardiac surgeries. We will then describe the relatively new field of molecular imaging that promises to translate research findings to the clinical practice by non-invasively monitoring the molecular signature of fibrosis in patients.

Systemic Cardiac Troponin T Associated With Incident Atrial Fibrillation Among Patients With Suspected Stable Angina Pectoris

Higher concentrations of cardiac troponin T are associated with coronary artery disease (CAD) and adverse cardiovascular prognosis. The relation with incident atrial fibrillation (AF) is less explored. We studied this association among 3,568 patients evaluated with coronary angiography for stable angina pectoris without previous history of AF. The prospective association between high-sensitivity cardiac troponin T (hs-cTnT) categories (≤3 ng/L; n = 1,694, 4-9; n = 1,085, 10 to 19; n = 614 and 20 to 30; n = 175) and incident AF and interactions with the extent of CAD were studied by Kaplan-Meier plots and Cox regression. Risk prediction improvements were assessed by receiver operating characteristic area under the curve (ROC-AUC) analyses. During median (25 to 75 percentile) 7.3 (6.3 to 8.6) years of follow-up 412 (11.5%) were diagnosed with AF. In a Cox model adjusted for age, gender, body mass index, hypertension, diabetes mellitus, smoking, estimated glomerular filtration rate, and left ventricular ejection fraction, hazard ratios (HRs) (95% confidence intervals [CIs]) were 1.53 (1.16 to 2.03), 2.03 (1.49 to 2.78), and 2.15 (1.40 to 3.31) when comparing the second, third, and fourth to the first hs-cTnT group, respectively (P for trend <0.000001). The strongest association between hs-cTnT levels and incident AF was found among patients without obstructive CAD (P_int = 0.024) and adding hs-cTnT to established AF risk factors improved risk classification slightly (ΔROC 0.006, p = 0.044). In conclusion, in patients with suspected stable angina higher levels of hs-cTnT predicted increased risk of incident AF. This was most pronounced in patients without obstructive CAD suggesting an association not mediated by coronary disease.

Using High-Sensitivity Cardiac Troponin for the Exclusion of Inducible Myocardial Ischemia in Symptomatic Patients: A Cohort Study

BACKGROUND

The optimal noninvasive method for surveillance in symptomatic patients with stable coronary artery disease (CAD) is unknown.

OBJECTIVE

To apply a novel approach using very low concentrations of high-sensitivity cardiac troponin I (hs-cTnI) for exclusion of inducible myocardial ischemia in symptomatic patients with CAD.

DESIGN

Prospective diagnostic cohort study. (ClinicalTrials.gov: NCT01838148).

SETTING

University hospital.

PATIENTS

1896 consecutive patients with CAD referred with symptoms possibly related to inducible myocardial ischemia.

MEASUREMENTS

Presence of inducible myocardial ischemia was adjudicated using myocardial perfusion imaging with single-photon emission computed tomography, as well as coronary angiography and fractional flow reserve measurements where available. Staff blinded to adjudication measured circulating hs-cTn concentrations. An hs-cTnI cutoff of 2.5 ng/L, derived previously in mostly asymptomatic patients with CAD, was assessed. Predefined target performance criteria were at least 90% negative predictive value (NPV) and at least 90% sensitivity for exclusion of inducible myocardial ischemia. Sensitivity analyses were based on measurements with an hs-cTnT assay and an alternative hs-cTnI assay with even higher analytic sensitivity (limit of detection, 0.1 ng/L).

RESULTS

Overall, 865 patients (46%) had inducible myocardial ischemia. The hs-cTnI cutoff of 2.5 ng/L provided an NPV of 70% (95% CI, 64% to 75%) and a sensitivity of 90% (CI, 88% to 92%) for exclusion of inducible myocardial ischemia. No hs-cTnI cutoff reached both performance characteristics predefined as targets. Similarly, using the alternative assays for hs-cTnI or hs-cTnT, no cutoff achieved the target performance: hs-cTnT concentrations less than 5 ng/L yielded an NPV of 66% (CI, 59% to 72%), and hs-cTnI concentrations less than 2 ng/L yielded an NPV of 68% (CI, 62% to 74%).

LIMITATION

Data were generated in a large single-center diagnostic study using central adjudication.

CONCLUSION

In symptomatic patients with CAD, very low hs-cTn concentrations, including hs-cTnI concentrations less than 2.5 ng/L, do not generally allow users to safely exclude inducible myocardial ischemia.

PRIMARY FUNDING SOURCE

European Union, Swiss National Science Foundation, Kommission für Technologie und Innovation (Innosuisse), Swiss Heart Foundation, Cardiovascular Research Foundation Basel, University of Basel, University Hospital Basel, Roche, Abbott, and Singulex.

Age-Biomarkers-Clinical Risk Factors for Prediction of Cardiovascular Events in Patients With Coronary Artery Disease

Objective- In patients with stable coronary artery disease, conventional risk factors provide limited incremental predictive value for cardiovascular events. We sought to investigate whether a panel of cardiometabolic biomarkers alone or combined with conventional risk factors would exhibit incremental value in the prediction of cardiovascular events. Approach and Results- In the discovery cohort, we measured serum adiponectin, A-FABP (adipocyte fatty acid-binding protein), lipocalin-2, FGF (fibroblast growth factor)-19 and 21, plasminogen activator inhibitor-1, and retinol-binding protein-4 in 1166 Chinese coronary artery disease patients. After a median follow-up of 35 months, 170 patients developed new-onset major adverse cardiovascular events (MACE). In the model with age ≥65 years and conventional risk factors, area under the curve for predicting MACE was 0.68. Addition of lipocalin-2 to the age-clinical risk factor model improved predictive accuracy (area under the curve=0.73). Area under the curve further increased to 0.75 when a combination of lipocalin-2, A-FABP, and FGF-19 was added to yield age-biomarkers-clinical risk factor model. The adjusted hazard ratio on MACEs for lipocalin-2, A-FABP, and FGF-19 levels above optimal cutoffs were 2.23 (95% CI, 1.62-3.08), 1.99 (95% CI, 1.43-2.76), and 1.65 (95% CI, 1.15-2.35), respectively. In the validation cohort of 1262 coronary artery disease patients with type 2 diabetes mellitus, the age-biomarkers-clinical risk factor model was confirmed to provide good discrimination and calibration over the conventional risk factor alone for prediction of MACE. Conclusions- A combination of the 3 biomarkers, lipocalin-2, A-FABP, and FGF-19, with clinical risk factors to yield the age-biomarkers-clinical risk factor model provides an optimal and validated prediction of new-onset MACE in patients with stable coronary artery disease.

Acupuncture to Improve Symptoms for Stable Angina: Protocol for a Randomized Controlled Trial

Background

Acupuncture has demonstrated physiologic analgesic effects in Chinese patients with stable angina. One proposed mechanism of action for these analgesic effects is the downregulation of M1 macrophages, interleukin 1 beta, interleukin-6, interleukin-18, and tumor necrosis factor alpha.

Objective

This study aims to test a 10-session, 5-week acupuncture treatment protocol as a complementary therapy for symptoms of stable angina for American patients, who vary from Chinese patients in health care systems and other salient variables.

Methods

We are conducting a randomized controlled trial (RCT) of 69 adults (35 assigned to initial acupuncture and 34 to an attention control condition) with a medically confirmed diagnosis of stable angina, whose pain and associated symptoms have not been controlled to their satisfaction with guideline-directed medical management. Participants in the experimental group will receive a standardized traditional Chinese medicine point prescription. The attention control group will view non–pain-related health education videos over 5 weeks equal to the 10 hours of treatment for the acupuncture group. Participants will complete the McGill Pain Questionnaire and the Seattle Angina Questionnaire-7, as well as have inflammatory cytokines measured at baseline and study completion. The primary outcomes are anginal pain and quality of life.

Results

This study has been funded over 2 years by the National Institutes of Health, National Institute for Nursing Research. We are currently recruiting and expect to have initial results by December 2020.

Conclusions

We will generate data on feasibility, acceptability, effect sizes, and protocol revisions for a future fully powered RCT of the protocol. Findings will help determine if patients with persistent ischemic symptoms experience a proinflammatory state and hyperalgesia caused by multiple neural and immune processes not always relieved with medication.

International Registered Report Identifier (IRRID)

DERR1-10.2196/14705

Non-invasive Risk Stratification for Coronary Artery Disease: Is It Time for Subclassifications?

PURPOSE OF REVIEW

Coronary artery disease (CAD) is the leading contributor to cardiovascular disease; it is the most prevalent non-communicable disease globally and has high morbidity, mortality and health care cost. Risk stratification is defined as prevention or containment of disease prior to it occurring or progressing, and non-invasive surrogates include history, examination, biomarkers and non-invasive imaging. This review aims to highlight advancement in current diagnostic strategies and explores gaps for CAD secondary to atherosclerosis and non-obstructive vascular diseases.

RECENT FINDINGS

Cardiac risk scores have largely proven inadequate in risk stratifying heterogeneous patient populations. Greater emphasis should also be provided to posttest risk stratification. Non-invasive imaging with MRI is the most accurate but least cost efficacious presently due to availability and expertise. Echocardiography and nuclear imaging have good accuracy, but radiation limits the latter. Novel echocardiographic technologies may increase its appeal. Cardiac CT angiography is increasingly promising. Non-invasive and minimally invasive imaging has significantly influenced the cost-efficacy trajectory of coronary artery disease diagnosis and management. Recent studies suggest that future guidelines will incorporate more subclassifications from the findings of these novel technologies and for more diverse patient demographics.

Recommendations for Institutions Transitioning to High-Sensitivity Troponin Testing: JACC Scientific Expert Panel

High-sensitivity cardiac troponin (hs-cTn) I or T methods have been in use in certain regions for years but are now increasingly globally adopted, including in the United States. Accordingly, inevitable challenges are created for institutions transitioning from conventional cardiac troponin (cTn) assays. hs-cTn assays have higher analytic precision at lower concentrations, yielding greater clinical sensitivity for myocardial injury and allowing accurate recognition of small changes in troponin concentration (rise or fall) within a short time frame. Although much of the knowledge regarding troponin biology that was applicable with older troponin assays still holds true, considerable education regarding the differences between conventional cTn and hs-cTn is needed before medical systems convert to the newer methods. This includes a basic understanding of how hs-cTn testing differs from conventional cTn testing and how it is best deployed in different settings, such as the emergency department and inpatient services. This Expert Panel will review important concepts for institutional transition to hs-cTn methodology, providing recommendations useful for education before implementation.

Usefulness of Higher Levels of Cardiac Troponin T in Patients With Stable Angina Pectoris to Predict Risk of Acute Myocardial Infarction

In patients with stable angina, the association between high-sensitivity cardiac troponin T (hs-cTnT) and incident acute myocardial infarction (AMI), as well as pathophysiologic mechanisms accounting for an adverse prognosis, remain to be determined. We explored the association between hs-cTnT and future AMI among 3,882 patients evaluated for suspected stable angina pectoris and investigated to which extent hs-cTnT attenuated the relations between traditional coronary heart disease (CHD) risk factors and AMI. Associations between increasing hs-cTnT categories (≤3, 4 to 9, 10 to 19, and 20 to 30 ng/L) and risk of AMI were studied by Cox regression. We investigated whether the associations between traditional CHD risk factors and future AMI were influenced by adjusting for hs-cTnT. Median age was 62 years. During median (25th to 75th percentile) 8 (6.4 to 8.7) years of follow-up, 460 (11.8%) experienced an AMI. There was a strong association between hs-cTnT categories and risk of AMI. The relation was somewhat attenuated, but still present, when adjusting for potential confounders, traditional CHD risk factors, previous peripheral vascular disease, and percutaneous coronary intervention or coronary bypass surgery. Moreover, hs-cTnT slightly attenuated the risk relations between traditional CHD risk factors and incident AMI, but each risk factor remained significantly associated with AMI. In conclusion, among patients with suspected stable angina, hs-cTnT was positively related to incident AMI.

Cardiac Troponin T Concentrations, Reversible Myocardial Ischemia, and Indices of Left Ventricular Remodeling in Patients with Suspected Stable Angina Pectoris: a DOPPLER-CIP Substudy

BACKGROUND

Cardiac troponin T concentrations measured with high-sensitivity assays (hs-cTnT) provide important prognostic information for patients with stable coronary artery disease (CAD). However, whether hs-cTnT concentrations mainly reflect left ventricular (LV) remodeling or recurrent myocardial ischemia in this population is not known.

METHODS

We measured hs-cTnT concentrations in 619 subjects with suspected stable CAD in a prospectively designed multicenter study. We identified associations with indices of LV remodeling, as assessed by cardiac MRI and echocardiography, and evidence of myocardial ischemia diagnosed by single positron emission computed tomography.

RESULTS

Median hs-cTnT concentration was 7.8 ng/L (interquartile range, 4.8–11.6 ng/L), and 111 patients (18%) had hs-cTnT concentrations above the upper reference limit (&gt;14 ng/L). Patients with hs-cTnT &gt;14 ng/L had increased LV mass (144 ± 40 g vs 116 ± 34 g; P &lt; 0.001) and volume (179 ± 80 mL vs 158 ± 44 mL; P = 0.006), lower LV ejection fraction (LVEF) (59 ± 14 vs 62 ± 11; P = 0.006) and global longitudinal strain (14.1 ± 3.4% vs 16.9 ± 3.2%; P &lt; 0.001), and more reversible perfusion defects (P = 0.001) and reversible wall motion abnormalities (P = 0.008). Age (P = 0.009), estimated glomerular filtration rate (P = 0.01), LV mass (P = 0.003), LVEF (P = 0.03), and evidence of reversible myocardial ischemia (P = 0.004 for perfusion defects and P = 0.02 for LV wall motion) were all associated with increasing hs-cTnT concentrations in multivariate analysis. We found analogous results when using the revised US upper reference limit of 19 ng/L.

CONCLUSIONS

hs-cTnT concentrations reflect both LV mass and reversible myocardial ischemia in patients with suspected stable CAD.

Prospective Validation of a Biomarker-Based Rule Out Strategy for Functionally Relevant Coronary Artery Disease

BACKGROUND

This study aimed to prospectively advance a rule-out strategy for functionally significant coronary artery disease (CAD) by use of high-sensitivity cardiac troponin I (hs-cTnI) from bench to bedside, by application of a 3-step approach: validation in serum, correlation in plasma, and application on a clinical platform.

METHODS

Patients without known CAD referred for rest/stress myocardial perfusion single-photon emission tomography/computer tomography (MPI-SPECT/CT) were assigned to 3 consecutive cohorts: validation, correlation, and application. Functionally relevant CAD was adjudicated with the use of expert interpretation of MPI-SPECT/CT and, if available, coronary angiography. In the validation cohort resting hs-cTnI was measured in serum before stress testing with the research Erenna system, in serum and plasma in the correlation cohort with the research Erenna system, and in plasma in the application cohort with the clinical Clarity system.

RESULTS

Overall, functionally relevant CAD was adjudicated in 21% (304/1478) of patients. In the validation cohort (n = 613), hs-cTnI concentrations were significantly higher in patients with functionally relevant CAD (median 2.8 ng/L vs 1.9 ng/L, P &lt; 0.001) as compared to patients without functionally relevant CAD and allowed a rule out with 95% sensitivity in 14% of patients. In the correlation cohort (n = 606), hs-cTnI concentrations in serum and plasma strongly correlated (Spearman r = 0.921) and had similar diagnostic accuracy as quantified by the area under the receiver operating characteristic curve (0.686 vs 0.678, P = 0.425). In the application cohort (n = 555), very low hs-cTnI plasma concentrations (&lt; 0.5 ng/L) ruled out functionally relevant CAD with 95% sensitivity in 10% of patients.

CONCLUSIONS

A single resting plasma hs-cTnI measurement can safely rule out functionally relevant CAD in around 10% of patients without known CAD.