Prognostic utility of novel biomarkers of cardiovascular stress: the Framingham Heart Study

Soluble ST2 testing in the general population

ST2 is a member of the interleukin (IL)-1 receptor family biomarker, and circulating soluble ST2 concentrations are believed to reflect cardiovascular stress. Recent studies have demonstrated soluble ST2 to be a strong predictor of cardiovascular outcomes in community-based populations free of cardiovascular disease. This report reviews the role of soluble ST2 in relation to cardiovascular risk factors and clinical outcomes in the general population. Furthermore, the recommendations regarding the role of soluble ST2 in general population-based testing, as formulated by the International ST2 Consensus Panel, are presented. There may be a role for soluble ST2 in improving current risk-stratification strategies for the prediction of cardiovascular outcomes, potentially in combination with other biomarkers in a multimarker strategy. However, the role of soluble ST2 testing in the general population has not yet been conclusively established. Future studies investigating the clinical utility of soluble ST2 screening in the general population are warranted.

Structural heart disease and ST2: cross-sectional and longitudinal associations with echocardiography

To further explore the potential role of sST2 in the progression of cardiac disease, this section reviews both the associations with cross-sectional findings and longitudinal changes in cardiac structure and function measured by echocardiography and cardiac magnetic resonance imaging with sST2 levels in a variety of patient populations with or at-risk for cardiovascular disease. In a Pro-Brain Natriuretic Peptide Investigation of Dyspnea in the Emergency Department substudy in patients with acute dyspnea, sST2 levels were found associated with left ventricular ejection fraction (LVEF), and both estimated right ventricular (RV) systolic pressure and RV hypokinesis. In a large cohort of ambulatory patients referred for echocardiograms, sST2 was predominantly associated with RV and not LV structural findings. In contrast, in the Framingham Heart Study, a community cohort of >3,300 participants, sST2 was not associated with either echocardiographic finding, although in the Cardiovascular Health Study, sST2 appeared strongly associated with the presence of diastolic dysfunction. Little evidence exists on the relation of sST2 levels with longitudinal change in cardiac structure and function. A substudy of Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS) evaluated the association among LV remodeling (defined as an increase in LV end-systolic and -diastolic volumes), sST2, and the benefit of eplerenone and found that sST2 levels were good surrogates of left ventricular remodeling. In the same line, the ProBNP Outpatient Tailored Chronic Heart Failure (PROTECT) study found that more time spent with an sST2 level less than the cutoff of 35 ng/L identified patients with a greater probability of a decrease in LV diastolic index over 1 year.

Soluble ST2--analytical considerations

Suppression of tumorigenicity 2 (ST2, also known as interleukin [IL]-1 receptor-like-1) is an IL-1 receptor family member with transmembrane (ST2L) and soluble isoforms (sST2). ST2L is a membrane-bound receptor, and IL-33 is the functional ligand for ST2L. sST2, a soluble truncated form of ST2L, is secreted into the circulation and functions as a "decoy" receptor for IL-33, inhibiting IL-33/ST2L signaling. Blood concentrations of sST2 are increased in inflammatory diseases and heart disease and are considered a valuable prognostic marker in both conditions. In multiple clinical trials, sST2 has emerged as a clinically useful prognostic biomarker in patients with cardiac diseases. Interestingly, sST2 even provides prognostic information in low-risk community-based populations. In this review, we will discuss analytical considerations of measuring circulating sST2 including pre-analytical issues, such as in vitro stability of sST2, biological variation of sST2, and postanalytical issues, such as reference ranges and comparisons to diseased cohorts.

Impact of Sex on the Prognostic Value of High-Sensitivity Cardiac Troponin I in the General Population: The HUNT Study

BACKGROUND

A new, high-sensitivity assay for cardiac troponin I (hs-cTnI) permits evaluation of the prognostic value of cardiac troponins within the reference interval. Men have higher hs-cTnI concentrations than women, but the underlying pathophysiological mechanisms and prognostic implications are unclear. The aim of this study was to assess the potential impact of sex on the association between hs-cTnI and cardiovascular death.

METHODS

By use of the Architect STAT High-Sensitive Troponin assay, we measured hs-cTnI in 4431 men and 5281 women aged ≥20 years participating in the prospective observational Nord-Trøndelag Health Study (HUNT).

RESULTS

hs-cTnI was detectable in 98.5% of men and 94.7% of women. During a mean follow-up period of 13.9 years, 708 cardiovascular deaths were registered. hs-cTnI was associated with the incidence of cardiovascular death [adjusted hazard ratio (HR) per 1 SD in log hs-cTnI 1.23 (95% CI 1.15–1.31)], with higher relative risk in women than men [HR 1.44 (1.31–1.58) vs 1.10 (1.00–1.20); Pinteraction < 0.001]. This finding was mediated by both lower risk associated with low hs-cTnI concentrations in women than in men and higher risk associated with high concentrations of hs-cTnI in women than in men. Male sex was associated with a higher risk of cardiovascular death [HR 1.28 (1.11–1.49)], but after adjustment for hs-cTnI, this association disappeared [HR 0.87 (0.75–1.02)].

CONCLUSIONS

The prognostic value of hs-cTnI concentrations in the general population is stronger in women than in men. Subtle impairment of cardiovascular status may contribute to higher hs-cTnI concentrations in men, reflecting sex-dependent differences in cardiovascular risk.

High-sensitivity cardiac troponin I and B-type natriuretic Peptide as predictors of vascular events in primary prevention: impact of statin therapy

Supplemental Digital Content is available in the text.

Background—

Cardiac troponin and B-type natriuretic peptide (BNP) concentrations are associated with adverse cardiovascular outcome in primary prevention populations. Whether statin therapy modifies this association is poorly understood.

Methods and Results—

We measured high-sensitivity cardiac troponin I (hsTnI) in 12 956 and BNP in 11 076 participants without cardiovascular disease in the Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) trial before randomization to rosuvastatin 20 mg/d or placebo. Nearly 92% of participants had detectable circulating hsTnI, and 2.9% of men and 4.1% of women had levels above proposed sex-specific reference limits of 36 and 15 ng/L, respectively. hsTnI concentrations in the highest tertile were associated with a first major cardiovascular event (adjusted hazard ratio [aHR], 2.19; 95% confidence interval, 1.56–3.06; P for trend <0.001). BNP levels in the highest tertile were also associated a first cardiovascular event (aHR, 1.94; 95% confidence interval, 1.41–2.68; P for trend <0.001). The risk of all-cause mortality was elevated for the highest versus the lowest tertiles of hsTnI (aHR, 2.61; 95% confidence interval, 1.81–3.78; P for trend <0.001) and BNP (aHR, 1.45; 95% confidence interval, 1.03–2.04; P for trend 0.02). Rosuvastatin was equally effective in preventing a first cardiovascular event across categories of hsTnI (aHR range, 0.50–0.60) and BNP (aHR range, 0.42–0.67) with no statistically significant evidence of interaction (P for interaction=0.53 and 0.20, respectively).

Conclusions—

In a contemporary primary prevention population, baseline cardiac troponin I and BNP were associated with the risk of vascular events and all-cause mortality. The benefits of rosuvastatin were substantial and consistent regardless of baseline hsTnI or BNP concentrations.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00239681.

How do high glycemic load diets influence coronary heart disease?

Background

Diet has a significant relationship with the risk of coronary heart disease (CHD). Traditionally the effect of diet on CHD was measured with the biomarker for low-density lipoprotein (LDL) cholesterol. However, LDL is not the only or even the most important biomarker for CHD risk. A suitably integrated view of the mechanism by which diet influences the detailed CHD pathogenetic pathways is therefore needed in order to better understand CHD risk factors and help with better holistic CHD prevention and treatment decisions.

Methods

A systematic review of the existing literature was conducted. From this an integrated CHD pathogenetic pathway system was constructed. CHD biomarkers, which are found on these pathways, are the only measurable data to link diet with these CHD pathways. They were thus used to simplify the link between diet and the CHD mechanism. Data were systematically analysed from 294 cohort studies of CHD biomarkers constituting 1 187 350 patients.

Results and discussion

The resulting integrated analysis provides insight into the higher-order interactions underlying CHD and high-glycemic load (HGL) diets. A novel “connection graph” illustrates the measurable relationship between HGL diets and the relative risks attributed to the important CHD serological biomarkers.

The “connection graph” vividly shows that HGL diets not only influence the lipid and metabolic biomarkers, but also the inflammation, coagulation and vascular function biomarkers in an important way.

Conclusion

A focus primarily on the low density lipoprotein cholesterol biomarker for CHD risk has led to the traditional guidelines of CHD dietary recommendations. This has however inadvertently led to HGL diets. The influence of HGL diets on the other CHD biomarkers is not always fully appreciated. Thus, new diets or other interventions which address the full integrated CHD impact, as shown in this paper, are required.

Population risk prediction models for incident heart failure: a systematic review

BACKGROUND

The prevalence of heart failure is expected to significantly rise unless high-risk patients are effectively screened and appropriate, cost-effective prevention interventions are implemented.

METHODS AND RESULTS

We performed a systematic review to evaluate the prediction characteristics of the published heart failure risk prediction models as of August 2014 using MEDLINE and EMBASE databases. Eligible studies reported the development, validation, or impact assessment of a model. Two investigators performed independent review to extract data on study design and characteristics, risk predictors, discrimination, calibration, and reclassification ability of models, as well as validation and impact analysis. We included 13 publications reporting on 28 heart failure risk prediction models. Models had acceptable-to-good discriminatory ability (c-statistics, >0.70) in the derivation sample. Calibration was less commonly assessed, but was acceptable when it was. Only 2 models were externally validated more than once, displaying modest-to-acceptable discrimination (c-statistics, 0.61-0.79). When assessed, novel blood and imaging markers modestly improved risk prediction. One model assessed the prediction properties in race-based subgroups, whereas 2 models evaluated sex-based subgroups. Impact analysis found none of the models recommended for use in any clinical practice guideline.

CONCLUSIONS

Incident heart failure risk prediction remains at an early stage. The discrimination ability of current models is acceptable in derivation data sets but most models have not been externally validated. It remains unclear which models are cost-effective and best suit population screening needs. The effects of models on clinical and preventative care requires further study.

Effects of B-type natriuretic peptide on cardiovascular biomarkers in healthy volunteers

Cardiovascular biomarkers provide independent prognostic information in the assessment of mortality and cardiovascular complications. However, little is known about possible interactions between these biomarkers. In the present study, we evaluated the influence of B-type natriuretic peptide (BNP) on midregional-proadrenomedullin (MR-proADM), C-terminal-proendothelin-1 (CT-proET-1), growth differentiation factor-15 (GDF-15), midregional-proatrial natriuretic peptide (MR-proANP), copeptin, and procalcitonin in healthy volunteers. Ten healthy male subjects (mean age 24 yr) participating in a randomized, placebo-controlled, single-blinded crossover study received placebo or 3.0 pmol·kg−1·min−1human BNP 32 during a continuous infusion lasting for 4 h. Effects of BNP on other cardiovascular biomarkers were assessed. BNP did not change concentrations of MR-proADM, copeptin, CT-proET1, GDF-15, or procalcitonin. In contrast, MR-proANP was significantly decreased during BNP infusion. BNP as an established cardiovascular biomarker did not affect plasma concentrations of other cardiovascular biomarkers in a model of healthy volunteers.

Soluble ST2 in Ventricular Dysfunction

Heart failure is a commonly encountered condition associated with increased morbidity, mortality, and healthcare cost. For years, its management has been strongly influenced by the use of B-type natriuretic peptide and N-terminal pro-B-type natriuretic peptide biomarkers. In some cases, this approach does not always identify patients with heart failure accurately and may not provide the best prognostic assessment, particularly in the presence of comorbidities. Biomarkers that help refine diagnosis and risk stratification are needed. Soluble ST2, a peptide belonging to the interleukin-1 receptor family, is secreted when cardiomyocytes and cardiac fibroblasts are subjected to mechanical strain. Although preliminary results on this novel biomarker are encouraging, additional and more comprehensive studies are clearly needed to establish its role in the management of patients with heart failure. The purpose of this chapter is to provide an overview of data currently available.

New risk markers for cardiovascular prevention

The importance of total cardiovascular (CV) risk estimation before management decisions are taken is well established. Models have been developed that allow physicians to stratify the asymptomatic population in subgroups at low, moderate, high, and very high total CV risk. Most models are based on classical CV risk factors: age, gender, smoking, blood pressure, and lipid levels. The impact of additional risk factors is discussed here, looking separately at the predictive increments of novel biomarkers and of indicators of subclinical atherosclerotic disease. The contribution of biomarkers to the total CV risk estimation is generally modest, and their usage should be limited to subjects at intermediate total CV risk. Detection of subclinical vascular damage may improve total CV risk estimation in asymptomatic subjects who are close to a threshold that could affect management decisions and in whom the chances of re-classification in a different risk category are great. There is, however, an urgent need for trials in which the value of using total CV risk estimation models is tested.

Identification of novel biomarkers for doxorubicin-induced toxicity in human cardiomyocytes derived from pluripotent stem cells

Doxorubicin is a chemotherapeutic agent indicated for the treatment of a variety of cancer types, including leukaemia, lymphomas, and many solid tumours. The use of doxorubicin is, however, associated with severe cardiotoxicity, often resulting in early discontinuation of the treatment. Importantly, the toxic symptoms can occur several years after the termination of the doxorubicin administration. In this study, the toxic effects of doxorubicin exposure have been investigated in cardiomyocytes derived from human embryonic stem cells (hESC). The cells were exposed to different concentrations of doxorubicin for up to 2 days, followed by a 12 day recovery period. Notably, the cell morphology was altered during drug treatment and the cells showed a reduced contractile ability, most prominent at the highest concentration of doxorubicin at the later time points. A general cytotoxic response measured as Lactate dehydrogenase leakage was observed after 2 days’ exposure compared to the vehicle control, but this response was absent during the recovery period. A similar dose-dependant pattern was observed for the release of cardiac specific troponin T (cTnT) after 1 day and 2 days of treatment with doxorubicin. Global transcriptional profiles in the cells revealed clusters of genes that were differentially expressed during doxorubicin exposure, a pattern that in some cases was sustained even throughout the recovery period, suggesting that these genes could be used as sensitive biomarkers for doxorubicin-induced toxicity in human cardiomyocytes. The results from this study show that cTnT release can be used as a measurement of acute cardiotoxicity due to doxorubicin. However, for the late onset of doxorubicin-induced cardiomyopathy, cTnT release might not be the most optimal biomarker. As an alternative, some of the genes that we identified as differentially expressed after doxorubicin exposure could serve as more relevant biomarkers, and may also help to explain the cellular mechanisms behind the late onset apoptosis associated with doxorubicin-induced cardiomyopathy.

Making sense of high sensitivity troponin assays and their role in clinical care

Cardiac troponin assays have an established and undisputed role in the diagnosis and risk stratification of patients with acute myocardial infarction. As troponin assays gets more sensitive and more precise, the number of potential uses has rapidly expanded, but the use of this test has also become more complicated and controversial. Highly sensitive troponin assays can now detect troponin levels in most individuals, but accurate interpretation of these levels requires a clear understanding of the assay in the context of the clinical scenario. This paper provides a practical and up-to-date overview of the uses of highly sensitive troponin assays for diagnosis, prognosis, and risk stratification in clinical practice.

Antibody-based proteomics and biomarker research - current status and limitations

Antibody-based proteomics play a very important role in biomarker discovery and validation, facilitating the high-throughput evaluation of candidate markers. Most proteomics-driven discovery is nowadays based on the use of MS. MS has many advantages, including its suitability for hypothesis-free biomarker discovery, since information on protein content of a sample is not required prior to analysis. However, MS presents one main caveat which is the limited sensitivity in complex samples, especially for body fluids, where protein expression covers a huge dynamic range. Antibody-based technologies remain the main solution to address this challenge since they reach higher sensitivity. In this article, we review the benefits and limitations of antibody-based proteomics in preclinical and clinical biomarker research for discovery and validation in body fluids and tissue. The combination of antibodies and MS, utilizing the best of both worlds, opens new avenues in biomarker research.

B-type natriuretic peptides improve cardiovascular disease risk prediction in a cohort of women

BACKGROUND

Although N-terminal pro-B-type natriuretic peptide (NT-proBNP) has a strong relationship with incident cardiovascular disease (CVD), few studies have examined whether NT-proBNP adds to risk prediction algorithms, particularly in women.

OBJECTIVES

This study sought to evaluate the relationship between NT-proBNP and incident CVD in women.

METHODS

Using a prospective case-cohort within the WHI (Women's Health Initiative) observational study, we selected 1,821 incident cases of CVD (746 myocardial infarctions, 754 ischemic strokes, 160 hemorrhagic strokes, and 161 other cardiovascular [CV] deaths) and a randomly selected reference cohort of 1,992 women without CVD at baseline.

RESULTS

Median levels of NT-proBNP were higher at study entry among incident cases (120.3 ng/l [interquartile range (IQR): 68.1 to 219.5 ng/l]) than among control subjects (100.4 ng/l [IQR: 59.7 to 172.6 ng/l]; p < 0.0001). Women in the highest quartile of NT-proBNP (≥140.8 ng/l) were at 53% increased risk of CVD versus those in the lowest quartile after adjusting for traditional risk factors (1.53 [95% confidence interval (CI): 1.21 to 1.94]; p for trend <0.0001). Similar associations were observed after adjustment for Reynolds Risk Score covariables (1.53 [95% CI: 1.20 to 1.95]; p for trend <0.0001); the association remained in separate analyses of CV death (2.66 [95% CI: 1.48 to 4.81]; p for trend <0.0001), myocardial infarction (1.39 [95% CI: 1.02 to 1.88]; p for trend = 0.008), and stroke (1.60 [95% CI: 1.22 to 2.11]; p for trend <0.0001). When added to traditional risk covariables, NT-proBNP improved the c-statistic (0.765 to 0.774; p = 0.0003), categorical net reclassification (0.08; p < 0.0001), and integrated discrimination (0.0105; p < 0.0001). Similar results were observed when NT-proBNP was added to the Reynolds Risk Score.

CONCLUSIONS

In this multiethnic cohort of women with numerous CV events, NT-proBNP modestly improved measures of CVD risk prediction.

Ideal cardiovascular health: associations with biomarkers and subclinical disease and impact on incidence of cardiovascular disease in the Framingham Offspring Study

BACKGROUND

The American Heart Association Cardiovascular Health score (CVH score) is inversely associated with cardiovascular disease (CVD) incidence, but the mechanisms underlying this association warrant exploration.

METHODS AND RESULTS

We related the CVH score to circulating biomarkers and prevalent subclinical CVD (defined as ≥1 of the following: increased carotid intima-media thickness or stenosis, left ventricular hypertrophy [by ECG or echocardiography], left ventricular systolic dysfunction, microalbuminuria, and a reduced ankle-brachial index) in 2680 Framingham Study participants (mean age, 58 years; 55% women). After adjustment for age and sex, an ideal CVH score (nonsmoking status, ideal body mass index, regular physical activity, healthy diet, and an optimal profile of serum cholesterol, blood pressure, and glucose; 1 point for each) was associated with higher circulating concentrations of natriuretic peptides (N-terminal pro-atrial natriuretic peptide and B-type natriuretic peptide) and lower blood concentrations of plasminogen activator inhibitor-1, aldosterone, C-reactive protein, D-dimer, fibrinogen, homocysteine, and growth differentiation factor-15 levels (P<0.001 for all), as well as lower odds of subclinical disease (odds ratio, 0.74 per 1-unit increase in CVH score; 95% confidence interval, 0.68-0.80). The incidence of CVD (267 events over 16 years) was inversely associated with the CVH score in age- and sex-adjusted models (hazard ratio, 0.77 per 1-unit increase in CVH score; 95% confidence interval, 0.70-0.86), which was slightly attenuated upon adjustment for biomarkers and subclinical disease (hazard ratio, 0.87; 95% confidence interval, 0.78-0.97).

CONCLUSION

In our prospective community-based study, the inverse association between an ideal cardiovascular health score and CVD incidence was partly attributable to its favorable impact on CVD biomarker levels and subclinical disease.

Soluble ST2 in heart failure

In addition to routine clinical laboratory tests (including natriuretic peptides and cardiac troponins), other biomarkers are gaining attention for their utility in heart failure (HF) management. Among them, soluble ST2 (sST2) a novel biomarker integrating inflammation, fibrosis, and cardiac stress has been included in the 2013 ACCF/AHA guideline for additive risk stratification of patients with acute and chronic HF. sST2 is an interleukin-1 (IL-1) receptor family member, is secreted into the circulation and functions as a "decoy" receptor for IL-33, inhibiting IL-33/ST2 signaling. Blood concentrations of sST2 are increased in various diseases such as inflammatory diseases and heart diseases and are considered a valuable prognostic marker in both conditions. sST2 lacks disease specificity and, therefore, is not a valuable marker for the diagnosis of HF. In acute and chronic HF, however, sST2 is strongly associated with measures of HF severity and poor outcome. Several studies in patients with HF indicate that serial measurement of sST2 has prognostic value and could have a potential role in future biomarker-directed therapy. In this review, the role of sST2 as a HF biomarker will be discussed, specifically addressing analytical considerations of measuring sST2 as well as the clinical applications of measurement of sST2 for the diagnosis, prognosis and monitoring of acute and chronic HF.

Biomarkers of cardiovascular stress and subclinical atherosclerosis in the community

BACKGROUND

Biomarkers of cardiovascular stress have been associated with incident cardiovascular outcomes. Their relations with measures of subclinical atherosclerosis, as assessed by carotid intima-media thickness, have not been well described.

METHODS

We measured plasma growth differentiation factor-15 (GDF-15), soluble ST2 (sST2), and high-sensitivity troponin I (hsTnI) in 3111 Framingham Offspring participants who also underwent carotid ultrasonography during the sixth examination (1995-1998, mean age 58 years, 54% women). Carotid measurements included maximal internal carotid artery (ICA) intima-media thickness (IMT), plaque presence (defined as ICA IMT >1.5 mm), and mean common carotid artery IMT. We carried out multivariable regressions for carotid measurements vs biomarkers using linear and logistic models; P < 0.0056 was deemed statistically significant.

RESULTS

Maximal ICA IMT was significantly associated with plasma GDF-15 [β-estimate 0.04 per 1-U increase in log(GDF-15), SE 0.01, P < 0.0001]. Similarly, the odds of having carotid plaque increased 33% [odds ratio 1.33 per 1-U increase in log(GDF-15), 95% CI 1.20-1.48, P < 0.0001]. In contrast, there was no significant association of maximal ICA IMT or plaque presence with sST2 or hsTnI, and none of the 3 biomarkers was significantly associated with mean CCA IMT. GDF-15 was a stronger predictor of maximal ICA thickness and plaque presence compared with BNP and CRP when these conventional biomarkers were tested together.

CONCLUSIONS

Increased GDF-15 concentrations are associated with subclinical atherosclerosis, including maximal ICA IMT and carotid plaque presence. Future studies investigating the role of GDF-15 for screening and management of patients with subclinical atherosclerosis are warranted.

Biofunctionalized rebar graphene (f-RG) for label-free detection of cardiac marker troponin I

One-step microwave-assisted unscrolling of carbon nanotubes to form functionalized rebar graphene (f-RG) is reported. The well-characterized f-RG on an interdigitated electrode biochip in a FET configuration showed enhanced electronic properties, as demonstrated with I-V characteristics. The developed device was biofunctionalized with specific anti-cTnI antibodies exhibiting a shift of threshold voltage from -2.15 V to -0.5 V and decrease in electron mobility from 3.609 × 10(4) to 8.877 × 10(3) cm(2) V(-1) s(-1). The new sensing strategy holds great promise for its applicability in diagnostics exhibiting high sensitivity (∼ 1 pg/mL) and specificity toward cardiac marker (cTnI).

Troponins in heart failure

The signs and symptoms of heart failure are frequently unspecific and correlate poorly with objective indices of cardiac function. Objective assessment of cardiac function by echocardiography or other imaging modalities also correlate poorly with symptomatic status and functional capacity. Accordingly, there is a need for circulating biomarkers that can provide incremental diagnostic and prognostic information to the existing armamentarium of tests. The introduction of more sensitive assays that allow determination of very low circulating concentrations of the myofibrillar proteins cardiac troponin I and T has not only resulted in improved diagnostic accuracy in the setting of acute coronary syndromes. The high sensitivity assays have also shown that cardiac troponins are frequently found chronically circulating in a variety of acute and chronic, cardiac and non-cardiac disease conditions, including acute heart failure and chronic symptomatic and asymptomatic left ventricular dysfunction. Cardiac troponin I and T provide may provide clinically useful prognostic information both concerning the future risk of developing heart failure in asymptomatic subjects and the risk of fatal events and hospital admissions in those with already established heart failure This review summarizes current literature on the clinical performance and utility of cardiac troponin measurements as diagnostic and prognostic tools in patients with symptomatic heart failure, as well as in those with asymptomatic left ventricular dysfunction, and clinical phenotypes at high risk for developing heart failure, including stable coronary artery disease, left ventricular hypertrophy, and aortic stenosis.

High-sensitivity cardiac troponin for risk prediction in patients with and without coronary heart disease

BACKGROUND

In stable patients with unknown coronary anatomy, higher levels of cardiac troponin are associated with an increased risk of cardiovascular events. It was supposed that this association might be explained by the ability of cardiac troponin to detect minor myocardial necrosis which might be caused by subclinical coronary atherosclerosis. Thus, this analysis tested if the predictive value of high-sensitivity troponin T (hsTnT) in stable patients is dependent of the presence or absence of angiographically documented coronary heart disease.

METHODS

Stable patients undergoing elective coronary angiography were enrolled (n=2046). HsTnT was determined before diagnostic procedures. The patients were followed for up to seven years. Primary endpoint was all-cause mortality or non-fatal myocardial infarction. All endpoints were adjudicated by independent physicians. Results were adjusted to a clinical model including independent clinical predictors of the primary endpoint.

RESULTS

Out of the 2046 patients enrolled, 1236 (60%) had a diagnosis of obstructive coronary heart disease. HsTnT predicted independently the primary endpoint (adjusted HR 1.33, 95%-CI 1.21-1.46, P<0.001). The use of hsTnT in addition to the clinical model significantly improved discrimination (c-statistic: 0.751 to 0.773, P<0.001) as well as reclassification of the primary endpoint (NRI=0.362, P<0.001). This significant improvement persisted across various subsets and was independent of the presence of clinically detectable coronary heart disease and other variables.

CONCLUSION

The use of hsTnT in addition to clinical variables significantly improves discrimination and reclassification of patients with respect to all-cause mortality or non-fatal myocardial infarction irrespective of the presence of clinically detectable coronary heart disease.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov (Identifier: NCT00457236).

Do cardiac biomarkers NT-proBNP and hsTnT predict microvascular events in patients with type 2 diabetes? Results from the ADVANCE trial

OBJECTIVE

We investigated microvascular event risk in people with type 2 diabetes and assessed whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin T (hsTnT) improved prediction.

RESEARCH DESIGN AND METHODS

We performed a case-cohort study, including 439 incident cases of microvascular events (new or worsening nephropathy or retinopathy) and 2,946 noncase subjects identified from participants in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial. NT-proBNP and hsTnT were measured in stored plasma samples using automated commercial assays.

RESULTS

After adjustment for age, sex, and randomized treatment, the hazard ratios for microvascular events per 1-SD increase in the log-transformed hsTnT and NT-proBNP were 1.67 (95% CI 1.51-1.85) and 1.63 (1.44-1.84), respectively. After further adjustment for classical and diabetes-related cardiovascular disease risk factors, the hazard ratios attenuated to 1.40 (1.24-1.58) and 1.41 (1.24-1.60), respectively. While the C statistic did not improve on addition of hsTnT or NT-proBNP for the total microvascular end point, a combination of both markers improved the prediction of nephropathy (P = 0.033) but not retinopathy (P = 0.72). The corresponding net reclassification indices in a three-risk category model (<10%, 10-15%, and >15% 5-year risk) for all microvascular events were 7.31% (95% CI 2.24-12.79) for hsTNT addition, 6.23% (1.74-11.5) for NT-proBNP addition, and 7.1% (1.5-12.9) for both markers together.

CONCLUSIONS

These data suggest that cardiac biomarkers moderately improve microvascular event risk prediction, in particular the risk of nephropathy. Further studies examining the value of this approach for trial design and clinical use are warranted.

Biomarkers of coronary artery disease: the promise of the transcriptome

The last years have witnessed tremendous technical advances in the field of transcriptomics that enable the simultaneous assessment of nearly all transcripts expressed in a tissue at a given time. These advances harbor the potential to gain a better understanding of the complex biological systems and for the identification and development of novel biomarkers. This article will review the current knowledge of transcriptomics biomarkers in the cardiovascular field and will provide an overview about the promises and challenges of the transcriptomics approach for biomarker identification.

Cardiac and kidney markers for cardiovascular prediction in individuals with chronic kidney disease: the Atherosclerosis Risk in Communities study

OBJECTIVE

Traditional predictors suboptimally predict cardiovascular disease (CVD) in individuals with chronic kidney disease (CKD). This study compared 5 nontraditional cardiac and kidney markers on the improvement of cardiovascular prediction among those with CKD.

APPROACH AND RESULTS

Among 8622 participants aged 52 to 75 years in the Atherosclerosis Risk in Communities (ARIC) Study, cardiac troponin T, N-terminal pro-B-type natriuretic peptide, cystatin C, β2-microglobulin, and β-trace protein were compared for improvement in predicting incident CVD after stratifying by CKD status (940 participants with CKD [kidney dysfunction or albuminuria]). During a median follow-up of 11.9 years, there were 1672 CVD events including coronary disease, stroke, and heart failure (336 cases in CKD). Every marker was independently associated with incident CVD in participants with and without CKD. The adjusted hazard ratios (per 1 SD) were larger for cardiac markers than for kidney markers, particularly in CKD (1.61 [95% confidence interval, 1.43-1.81] for cardiac troponin T, 1.50 [1.34-1.68] for N-terminal pro-B-type natriuretic peptide, and <1.26 for kidney markers). Particularly in CKD group, cardiac markers compared with kidney markers contributed to greater c-statistic increment (0.032-0.036 versus 0.012-0.015 from 0.679 with only conventional predictors in CKD and 0.008-0.011 versus 0.002-0.010 from 0.697 in non-CKD) and categorical net reclassification improvement (0.086-0.127 versus 0.020-0.066 in CKD and 0.057-0.077 versus 0.014-0.048 in non-CKD). The superiority of cardiac markers was largely consistent in individual CVD outcomes.

CONCLUSIONS

A greater improvement in cardiovascular prediction was observed for cardiac markers than for kidney markers in people with CKD. These results suggest that cardiac troponin T and N-terminal pro-B-type natriuretic peptide are useful for better CVD risk classification in this population.

Modulation of IL-33/ST2 system in postinfarction heart failure: correlation with cardiac remodelling markers

BACKGROUND

Interleukin (IL)-33 and sST2 are molecules with an opposite pathophysiologic implications in the myocardial response after acute myocardial infarction (AMI). Both may be a target for therapeutic interventions. The kinetics of IL-33 and sST2 expression in infarcted myocardium and their correlation with the ongoing processes of fibrosis, inflammation and apoptosis remains poorly defined.

MATERIALS AND METHODS

Fifty Wistar rats underwent left anterior descending coronary artery surgical ligation and were sacrificed at 1, 2, 4, 12 or 24 weeks post-AMI. A sham-operated group was also included. The mRNA cardiac expression levels of IL-33, sST2, fibrosis markers, inflammatory markers and apoptosis markers were assessed by RT-PCR. The protein expression of IL-33 was also measured by Western blotting.

RESULTS

The mRNA levels of IL-33 and sST2 were upregulated in the infarcted myocardium during the first week after AMI. However, while IL-33 levels remained elevated during the first 12 weeks post-AMI, sST2 levels showed a marked drop at 4 weeks. IL-33 protein expression showed a similar kinetic than mRNA expression. The expression of sST2 positively correlated with cardiac gene expression of inflammatory and fibrosis markers. However, the IL-33 level did not correlate with these cardiac remodelling markers. No correlation of sST2 with apoptosis markers was observed.

CONCLUSION

After AMI, expression of sST2 is rapidly upregulated during the first 4 weeks and, in contrast to IL-33, its levels correlated with the ongoing processes of fibrosis and inflammation. These findings suggest differential regulation of IL33 and sST2. Therapeutic modulation of early sST2 expression may be of greater importance to prevent adverse remodelling after AMI.

High-sensitivity troponin I and amino-terminal pro--B-type natriuretic peptide predict heart failure and mortality in the general population

INTRODUCTION

High-sensitivity cardiac troponin assays have potent prognostic value in stable cardiovascular disease cohorts. Our objective was to assess the prognostic utility of a novel cardiac troponin I (cTnI) high-sensitivity assay, independently and in combination with amino-terminal pro-B-type natriuretic peptide (NT-proBNP), for the future development of heart failure and mortality in the general community.

METHODS

A well-characterized community-based cohort of 2042 participants underwent clinical assessment and echocardiographic evaluation. Baseline measurements of cTnI with a high-sensitivity assay and NT-proBNP were obtained in 1843 individuals. Participants were followed for new-onset heart failure and mortality with median (25th, 75th percentile) follow-up of 10.7 (7.9, 11.6) and 12.1 (10.4, 13.0) years, respectively.

RESULTS

When measured with a high-sensitivity assay, cTnI greater than the sex-specific 80th percentile was independently predictive of heart failure [hazard ratio 2.56 (95% confidence interval 1.88-3.50), P < 0.001] and mortality [1.91(1.49-2.46), P < 0.001] beyond conventional risk factors in this community-based cohort, with significant increases in the net reclassification improvement for heart failure. The prognostic utility of cTnI measured with a high-sensitivity assay goes beyond NT-proBNP, yet our data suggest that these 2 assays are complementary and most beneficial when evaluated together in identifying at-risk individuals in the community.

CONCLUSIONS

Our findings lay the foundation for prospective studies aimed at identification of individuals at high risk by use of a multimarker approach, followed by aggressive prevention strategies to prevent subsequent heart failure.

Charting a roadmap for heart failure biomarker studies

Heart failure is a syndrome with a pathophysiological basis that can be traced to dysfunction in several interconnected molecular pathways. Identification of biomarkers of heart failure that allow measurement of the disease on a molecular level has resulted in enthusiasm for their use in prognostication and selection of appropriate therapies. However, despite considerable amounts of information available on numerous biomarkers, inconsistent research methodologies and lack of clinical correlations have made bench-to-bedside translations rare and left the literature with countless publications of varied quality. There is a need for a systematic and collaborative approach aimed at definitively studying the clinical benefits of novel biomarkers. In this review, on the basis of input from academia, industry, and governmental agencies, we propose a systematized approach based on adherence to specific quality measures for studies looking to augment current prediction model or use biomarkers to tailor therapeutics. We suggest that study quality, rather than results, should determine publication and propose a system for grading biomarker studies. We outline the need for collaboration between clinical investigators and statisticians to introduce more advanced statistical methodologies into the field of biomarkers that would allow for data from a large number of variables to be distilled into clinically actionable information. Lastly, we propose the creation of a heart failure biomarker consortium that would allow for a comprehensive list of biomarkers to be concomitantly analyzed in a pooled sample of randomized clinical trials and hypotheses to be generated for testing in biomarker-guided trials. Such a consortium could collaborate in sharing samples to identify biomarkers, undertake meta-analyses on completed trials, and spearhead clinical trials to test the clinical utility of new biomarkers.

Combined effect of serum gamma-glutamyltransferase and uric acid on Framingham risk score

BACKGROUND AND AIMS

Gamma-glutamyltransferase (GGT) and uric acid (UA) are novel coronary heart disease (CHD) risk factors. In the present study we investigated the combined effects of GGT and UA on Framingham risk score (FRS) in a Korean population.

METHODS

A total of 10,096 subjects (5,124 females and 4,972 males) were enrolled in this study. A 10-year coronary heart disease (CHD) risk was calculated using the FRS modified by the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III). Levels of circulating GGT and UA were measured using validated assays.

RESULTS

The 10-year CHD risk gradually augmented with increase in the circulating levels of GGT and UA. For the highest quartile of GGT and UA, odds ratio (OR) of intermediate-risk and beyond for CHD (10-year risk ≥10%) compared with the lowest quartile was 3.44 (95% CI: 2.60-4.55, p <0.001) and 1.97 (95% CI: 1.56-4.55, p <0.001) after adjusting for confounders, respectively. OR of intermediate-risk and beyond for CHD in both 3(rd) and 4(th) quartile of GGT and UA was 9.9 (95% CI: 5.2-18.6) compared with the first quartile of those.

CONCLUSIONS

GGT and UA levels are well associated with the 10-year CHD risk estimated using NCEP ATP III in Koreans after adjusting for confounders and combination of GGT and UA levels can have a strong synergy in predicting the development of CHD.

Soluble ST2 and interleukin-33 levels in coronary artery disease: relation to disease activity and adverse outcome

Objectives

ST2 is a receptor for interleukin (IL)-33. We investigated an association of soluble ST2 (sST2) and IL-33 serum levels with different clinical stages of coronary artery disease. We assessed the predictive value of sST2 and IL-33 in patients with stable angina, non-ST elevation myocardial infarction (NSTEMI) and ST elevation myocardial infarction (STEMI).

Methods

We included 373 patients of whom 178 had stable angina, 97 had NSTEMI, and 98 had STEMI. Patients were followed for a mean of 43 months. The control group consisted of 65 individuals without significant stenosis on coronary angiography. Serum levels of sST2 and IL-33 were measured by ELISAs.

Results

sST2 levels were significantly increased in patients with STEMI as compared to patients with NSTEMI and stable angina as well as with controls. IL-33 levels did not differ between the four groups. During follow-up, 37 (10%) patients died and the combined endpoint (all cause death, MI and rehospitalisation for cardiac causes) occurred in 66 (17.6%) patients. sST2 serum levels significantly predicted mortality in the total cohort. When patients were stratified according to their clinical presentation, the highest quintile of sST2 significantly predicted mortality in patients with STEMI, but not with NSTEMI or stable coronary artery disease. sST2 was a significant predictor for the combined endpoint in STEMI patients and in patients with stable angina. Serum levels of IL-33 were not associated with clinical outcome in the total cohort, but the highest quintile of IL-33 predicted mortality in patients with STEMI.

Conclusions

Serum levels of sST2 are increased in patients with acute coronary syndromes as compared to levels in patients with stable coronary artery disease and in individuals without coronary artery disease. sST2 and IL-33 were associated with mortality in patients with STEMI but not in patients with NSTEMI or stable angina.

A sensitive aβ oligomer assay discriminates Alzheimer's and aged control cerebrospinal fluid

A hallmark of Alzheimer's disease (AD) brain is the amyloid β (Aβ) plaque, which is comprised of Aβ peptides. Multiple lines of evidence suggest that Aβ oligomers are more toxic than other peptide forms. We sought to develop a robust assay to quantify oligomers from CSF. Antibody 19.3 was compared in one-site and competitive ELISAs for oligomer binding specificity. A two-site ELISA for oligomers was developed using 19.3 coupled to a sensitive, bead-based fluorescent platform able to detect single photons of emitted light. The two-site ELISA was >2500× selective for Aβ oligomers over Aβ monomers with a limit of detection ∼ 0.09 pg/ml in human CSF. The lower limit of reliable quantification of the assay was 0.18 pg/ml and the antibody pairs recognized Aβ multimers comprised of either synthetic standards, or endogenous oligomers isolated from confirmed human AD and healthy control brain. Using the assay, a significant 3- to 5-fold increase in Aβ oligomers in human AD CSF compared with comparably aged controls was demonstrated. The increase was seen in three separate human cohorts, totaling 63 AD and 54 controls. CSF oligomers ranged between 0.1 and 10 pg/ml. Aβ oligomer levels did not strongly associate with age or gender, but had an inverse correlation with MMSE score. The C statistic for the Aβ oligomer ROC curve was 0.86, with 80% sensitivity and 88% specificity to detect AD, suggesting reasonable discriminatory power for the AD state and the potential for utility as a diagnostic marker.

Predictive value of high-sensitivity troponin-I for future adverse cardiovascular outcome in stable patients with type 2 diabetes mellitus

Introduction

High-sensitivity cardiac troponin I(hs-TnI) and T levels(hs-TnT) are sensitive biomarkers of cardiomyocyte turnover or necrosis. Prior studies of the predictive role of hs-TnT in type 2 diabetes mellitus(T2DM) patients have yielded conflicting results. This study aimed to determine whether hs-TnI, which is detectable in a higher proportion of normal subjects than hsTnT, is associated with a major adverse cardiovascular event(MACE) in T2DM patients.

Methods and results

We compared hs-TnI level in stored serum samples from 276 consecutive patients (mean age 65 ± 10 years; 57% male) with T2DM with that of 115 age-and sex-matched controls. All T2DM patients were prospectively followed up for at least 4 years for incidence of MACE including heart failure(HF), myocardial infarction(MI) and cardiovascular mortality. At baseline, 274(99%) patients with T2DM had detectable hs-TnI, and 57(21%) had elevated hs-TnI (male: 8.5 ng/L, female: 7.6 ng/L, above the 99^th percentile in healthy controls). A total of 43 MACE occurred: HF(n = 18), MI(n = 11) and cardiovascular mortality(n = 14). Kaplan-Meier analysis showed that an elevated hs-TnI was associated with MACE, HF, MI and cardiovascular mortality. Although multivariate analysis revealed that an elevated hs-TnI independently predicted MACE, it had limited sensitivity(62.7%) and positive predictive value(38.5%). Contrary to this, a normal hs-TnI level had an excellent negative predictive value(92.2%) for future MACE in patients with T2DM.

Conclusion

The present study demonstrates that elevated hs-TnI in patients with T2DM is associated with increased MACE, HF, MI and cardiovascular mortality. Importantly, a normal hs-TnI level has an excellent negative predictive value for future adverse cardiovascular events during long-term follow-up.

Comparison of three troponins as predictors of future cardiovascular events--prospective results from the FINRISK and BiomaCaRE studies

IMPORTANCE AND OBJECTIVE

Besides their role in diagnosis of acute myocardial infarction (MI), troponins may be powerful biomarkers for risk stratification in the general population. The objective of our study was to compare the performance of three troponin assays in cardiovascular disease (CVD) risk prediction in a population-based cohort without a history of CVD events.

DESIGN, SETTING AND PARTICIPANTS

Troponin I concentrations were measured using a contemporary-sensitivity, high-sensitivity, and super-sensitivity assay in 7,899 participants of the general-population based FINRISK 1997 cohort. We used Cox proportional hazards regression to determine relative risks, followed by measures of discrimination and reclassification using 10-fold cross-validation to control for over-optimism.

MAIN OUTCOME

As outcome measures we used CVD, MI, ischemic stroke, heart failure (HF), and major adverse cardiac events (MACE). During the follow-up of 14 years 1,074 incident MACE were observed.

RESULTS

Values above the lower limit of detection were observed in 26.4%, 81.5% and 93.9% for the contemporary-sensitivity, high-sensitivity and super-sensitivity assay, respectively. We observed significant associations of troponin concentrations with the risk of future CVD events and the results tended to become stronger with increasing assay sensitivity. For the super-sensitivity assay the multivariate adjusted hazard ratios (per one standard deviation increase) for different outcomes were: MI 1.24 [95% CI 1.11-1.39], stroke 1.14 [1.01-1.28], CVD 1.15 [1.07-1.24], HF 1.28 [1.18-1.39], and MACE 1.18 [1.11-1.25]. In subjects with intermediate risk, we found an improvement of net reclassification for HF (10.2%, p<0.001), and MACE (5.1%, p<0.001).

CONCLUSION

Using a super-sensitivity assay, cardiac troponin was detectable in almost all healthy individuals. Its concentration improved risk prediction and reclassification for cardiovascular endpoints.

Increased Soluble ST2 Predicts Long-term Mortality in Patients with Stable Coronary Artery Disease: Results from the Ludwigshafen Risk and Cardiovascular Health Study

BACKGROUND

Soluble suppression of tumorigenicity 2 (sST2) has emerged as a strong prognostic biomarker in patients with heart failure and myocardial infarction. The aim of this study was to evaluate the long-term prognostic value of sST2 in patients with stable coronary artery disease (CAD).

METHODS

sST2 plasma concentrations were measured in 1345 patients with stable CAD referred for coronary angiography at a single tertiary care center. The primary endpoint was all-cause mortality.

RESULTS

During a median follow-up time of 9.8 years, 477 (36%) patients died. The median sST2 plasma concentration at baseline was significantly higher among decedents than survivors (21.4 vs 18.5 ng/mL; P &lt; 0.001). In multivariate Cox proportional hazards regression analysis, sST2 was an independent predictor of all-cause mortality (risk ratio 1.16 per 1-SD increase in log-transformed values; 95% CI 1.05–1.29; P = 0.004). In the same multivariate analysis, amino-terminal pro–B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) were also independent predictors, whereas galectin-3 was not. Patients with sST2 in the highest quartile (&gt;24.6 ng/mL) displayed a 2-fold increased risk of death in univariate analysis, which was attenuated but remained significant in a fully adjusted model (risk ratio 1.39; 95% CI 1.10–1.76; P = 0.006). Further analysis showed that the prognostic impact of sST2 was additive to NT-proBNP and hs-cTnT. Using a multibiomarker approach combining these 3 complementary makers, we demonstrated that patients with all 3 biomarkers in the highest quartiles had the poorest outcome.

CONCLUSIONS

In this cohort of patients with stable CAD, increased sST2 was an independent predictor of long-term all-cause mortality and provided complementary prognostic information to hs-cTnT and NT-proBNP.

Reference interval evaluation of high-sensitivity troponin T and N-terminal B-type natriuretic peptide in Vietnam and the US: The North South East West Trial

BACKGROUND

Reference intervals of high-sensitivity troponin T (hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) have been determined from Western populations. No data are available regarding expected values in Asian populations.

METHODS

A total of 1157 age- and sex-matched healthy individuals (mean age, 41.2 years; 48.0% male) were prospectively enrolled from the US (n = 565) and Vietnam (n = 592). Blood samples were analyzed for hs-cTnT and NT-proBNP. Median values were determined for each country and compared in unadjusted analyses and in analyses adjusted for age, sex, body mass index, study site, race, and vital signs.

RESULTS

Median hs-cTnT concentrations were slightly higher for individuals from the US than for those from Vietnam, but both were below the limit of detection (3.7 vs 3.0 ng/L, respectively; P = 0.03). More US participants had an hs-cTnT concentration above the limit of detection (57.2% vs 47.3%; P = 0.001), but the 99th percentile concentration was slightly higher for Asians (US 15.1 vs Vietnam 19.0 ng/L). Concentrations for >98% of both populations were below the standard hs-cTnT 99th percentile of 14.0 ng/L (P = 0.54). Median NT-proBNP concentrations were slightly higher for US participants compared with Vietnamese participants (28 vs 16 ng/L, respectively; P < 0.001). Following adjustment, differences in concentrations of NT-proBNP between healthy US and Vietnamese populations remained significant, whereas for hs-cTnT the differences were no longer significant. Inclusion of hs-cTnT values down to the limit of blank did not change the result.

CONCLUSIONS

The differences in hs-cTnT and NT-proBNP between healthy individuals from the US and Vietnam are small. Previously derived reference intervals for both analytes may be applied in Asian populations.

Soluble ST2 predicts elevated SBP in the community

BACKGROUND

Soluble ST2 (sST2) is an emerging prognostic biomarker in patients with existing cardiovascular disease. ST2 and its ligand, interleukin-33 (IL-33), are expressed in endothelial cells, and may play an important role in the development of early atherosclerosis and vascular biology. We sought to investigate the association of sST2 and progression of blood pressure (BP), as well as the development of hypertension.

METHODS

Circulating sST2 concentrations were measured in 1834 participants (mean age 56 years, 57% women) of the community-based Framingham Offspring study. Participants were free of hypertension at baseline. Multivariable linear and logistic regression models were used to evaluate the association of sST2 concentrations and subsequent BP outcomes.

RESULTS

Higher sST2 concentrations were associated with incident hypertension over 3 years of follow-up [multivariable-adjusted odds ratio per 1 standard deviation increase in sST2 1.22, 95% confidence interval 1.05-1.42, P=0.01]. Individuals in the upper sST2 quartile had a 2.6 mmHg greater increase in SBP compared with those in the lowest quartile (P for trend across quartiles 0.002) and a 1.8 mmHg greater increase in pulse pressure (P for trend 0.005). In contrast, sST2 concentrations were not associated with changes in DBP (P=0.27).

CONCLUSION

These findings suggest that sST2 concentrations predict changes in BP physiology typically seen with aging and progressive arterial stiffness. Further studies are needed to elucidate underlying mechanisms by which the ST2/IL-33 pathway may contribute to BP physiology.

Risk of death in heart disease is associated with elevated urinary globotriaosylceramide

Background

Elevated urinary globotriaosylceramide (Gb₃) has been considered a hallmark of Fabry disease, an X‐linked lysosomal disorder that is a risk factor for most types of heart disease.

Methods and Results

We screened 1421 consecutive patients with common forms of heart disease for Fabry disease by measuring urinary Gb₃ in whole urine using tandem mass spectrometry, α‐galactosidase A activity in dried blood spots, and we looked for GLA mutations by parallel sequencing of the whole gene (exons and introns) in pooled genomic DNA samples followed by Sanger sequencing verification. GLA variants were found in 13 patients. In the 1408 patients without GLA mutations, urinary Gb₃ levels were significantly higher in heart disease patients compared to 116 apparently healthy controls (median difference=10.0 ng/mL and P<0.001). Urinary lipid profiling showed that levels of 5 other lipids significantly distinguished between urine of patients with Fabry disease (n=7) and heart disease patients with elevated urinary Gb₃ (n=6). Sphingomyelin and Gb₃ levels were abnormal in the left ventricular wall of patients with ischemic heart failure. Elevated levels of urinary Gb₃ were independently associated with increased risk of death in the average follow‐up of 17 months (hazard ratio=1.59 for increase in Gb₃ of 200, 95% CI=1.36 and 1.87, and P<0.0001).

Conclusions

In heart disease patients who do not have Fabry disease or GLA gene mutations, a higher level of urinary Gb₃ is positively associated with near‐term mortality. The elevation of urinary Gb₃ and that of other lipids suggests that heart disease is associated with multiorgan lipid abnormalities.

Clinical Trial Registration

URL: clinicaltrials.gov. Unique Identifier: NCT01019629.

Growth differentiation factor 15 and cardiovascular events in patients with stable ischemic heart disease (The Heart and Soul Study)

BACKGROUND

Growth differentiation factor 15 (GDF-15) is a relatively new biomarker that predicts mortality in patients with chronic stable angina or acute coronary syndrome. However, the association of GDF-15 with cardiovascular (CV) events and the mechanisms of this association are not well understood.

METHODS

We measured plasma GDF-15 and cardiac disease severity in 984 patients with stable ischemic heart disease who were recruited for the Heart and Soul Study between September 2000 and December 2002. Subsequent CV events (myocardial infarction, stroke, and CV death), hospitalization for heart failure, and all-cause mortality were determined by chart review during an average of 8.9-year follow-up.

RESULTS

Each doubling in GDF-15 was associated with a 2.5-fold increased rate of CV events (hazard ratio [HR] 2.53, 95% CI 2.13-3.01, P < .001). This association persisted after extensive adjustment for covariates including comorbid conditions, measures of cardiac disease severity, cardiac function, inflammatory markers, and adipokines (HR 1.44, 95% CI 1.11-1.87, P < .01). Participants who had GDF-15 levels in the highest tertile had higher mortality compared with those in the lowest tertile (HR 2.73, 95% CI 1.80-4.15, P ≤ .001 adjusted for all covariates). Addition of GDF-15 to existing risk factors resulted in a 50% change in net reclassification of patients' risk for mortality.

CONCLUSIONS

Higher levels of GDF-15 are associated with major CV events in patients with stable ischemic heart disease. This suggests that GDF-15 is capturing an element of risk not explained by other known risk factors.

Soluble ST2 and galectin-3 in heart failure

Circulating biomarkers that directly reflect disease progression, hemodynamics, and ventricular remodeling at a molecular level are critical to risk stratification in heart failure (HF), affording unique insights into pathophysiology not fully captured by traditional risk markers. Despite the wealth of data confirming the importance of natriuretic peptides in HF diagnosis and prognosis, residual clinical risk in HF suggests that additional biomarkers complementary to natriuretic peptides may be useful. In this article, the current literature addressing the role of these biomarkers in the clinical diagnosis and risk stratification in HF is summarized.

Relation between soluble ST2, growth differentiation factor-15, and high-sensitivity troponin I and incident atrial fibrillation

BACKGROUND

We investigated whether circulating concentrations of soluble ST2, growth differentiation factor-15 (GDF-15), and high-sensitivity troponin I (hsTnI) are associated with incident atrial fibrillation (AF) and whether these biomarkers improve current risk prediction models including AF risk factors, B-type natriuretic peptide (BNP), and C-reactive protein (CRP).

METHODS

We studied the relation between soluble ST2, GDF-15, and hsTnI and development of AF in Framingham Heart Study participants without prevalent AF. We used Cox proportional hazard regression analysis to examine the relation of incident AF during a 10-year follow-up period with each biomarker. We adjusted for standard AF clinical risk factors, BNP, and CRP.

RESULTS

The mean age of the 3,217 participants was 59 ± 10 years, and 54% were women. During a 10-year follow-up, 242 participants developed AF. In age- and sex-adjusted models, GDF-15 and hsTnI were associated with risk of incident AF; however, after including the AF risk factors and BNP and CRP, only hsTnI was significantly associated with AF (hazard ratio per 1 SD of loge hsTnI, 1.12, 95% CI 1.00-1.26, P = .045). The c statistic of the base model including AF risk factors, BNP, and CRP was 0.803 (95% CI 0.777-0.830) and did not improve by adding individual or all 3 biomarkers. None of the discrimination and reclassification statistics were significant compared with the base model.

CONCLUSION

In a community-based cohort, circulating hsTnI concentrations were associated with incident AF. None of the novel biomarkers evaluated improved AF risk discrimination or reclassification beyond standard clinical AF risk factors and biomarkers.

Biomarkers in ACS and Heart Failure: Should Men and Women Be Interpreted Differently?

BACKGROUND

Sex-based differences exist in the circulating concentrations of certain novel and established biomarkers in patients with acute coronary syndromes (ACS) and heart failure (HF). However, to date, few studies have compared the diagnostic and prognostic utility of these markers in men vs women.

CONTENT

This mini-review contains a discussion of the published reports of studies that have explored whether differences in biomarker concentrations exist between men and women with ACS or HF. It also examines those studies that have compared the utility of biomarkers for diagnosis or risk stratification in women vs men. Because biomarkers are often used to make therapeutic and triage decisions in patient care, the potential clinical implications for any observed differences in biomarker reference limits for men and women is discussed.

SUMMARY

Although the concentration distributions may differ between men and women for certain biomarkers in clinical use, the clinical implications of these observations remain unclear. Because elements of the pathophysiology of ACS and HF may differ between the sexes, further research is needed to better evaluate the diagnostic and prognostic utility of biomarkers in men vs women.