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

Sex-specific differences in risk factors, comorbidities, diagnostic challenges, optimal management, and prognostic outcomes of heart failure with preserved ejection fraction: A comprehensive literature review

Due to hormonal variations, heart failure with preserved ejection fraction (HFpEF) remains prevalent in women and affects almost half of the heart failure (HF) patients. Given the yearly death rate of 10-30% and the unavailability of medications targeting HFpEF, the need arises for a better understanding of the fundamental mechanisms of this syndrome. This comprehensive review explores sex-specific differences in traditional risk factors; female-specific factors that may impact HFpEF development and response to therapy, including variations in hormone levels that may occur pre- and post-menopausal or during pregnancy; and disparities in comorbidities, clinical presentation, and diagnostic challenges. Lastly, the review addresses prognostic outcomes, noting that women with HFpEF have a poor quality of life but a higher survival rate. It also discusses novel biomarkers and precision medicine, emphasizing their potential to improve early detection and personalized treatment.

Risk Factors and Cellular Differences in Heart Failure: The Key Role of Sex Hormones

Patients with heart failure are conventionally stratified into phenotypic groups based on their ejection fraction. The aim of this stratification is to improve disease management with a more targeted therapeutic approach. A further subdivision based on patient gender is justified. It is recognized that women are underrepresented in randomized controlled clinical trials, resulting in limited clinical and molecular differentiation between males and females. However, many observational studies show that the onset, development, and clinical course of the disease may substantially differ between the two sexes. According to the emerging concept of precision medicine, investigators should further explore the mechanisms responsible for the onset of heart failure due to sex differences. Indeed, the synergistic or opposing effects of sex hormones on the cardiovascular system and underlying heart failure mechanisms have not yet been clarified. Sex hormones, risk factors impact, and cardiovascular adaptations may be relevant for a better understanding of the intrinsic pathophysiological mechanisms in the two sexes. Despite the differences, treatment for HF is similar across the whole population, regardless of sex and gender. In our review, we describe the main differences in terms of cardiovascular dysfunction, risk factors, and cellular signaling modifications related to the hormonal pattern.

The diagnostic utility of creatine kinase-MB versus total creatine phosphokinase ratio in patients with non-ST elevation myocardial infarction from unstable angina

Objective:

The present study seeks to find a way to quickly and correctly differentiate myocardial infarction from unstable angina by measuring the creatine kinase-MB/creatine phosphokinase ratio and comparing in non-ST elevation myocardial infarction patients with unstable angina at different time intervals, to improve the health quality of patients with coronary artery disease.

Methods:

The present study is a retrospective epidemiological analysis of 260 patients with non-ST elevation myocardial infarction and 260 patients with unstable angina, including age, sex, creatine kinase-MB, and creatine phosphokinase biomarkers at two-time intervals, including referral (4–8 h from the onset of pain) as the first interval, and 8 h after the first sampling was extracted as the second interval. Moreover, the delta of the creatine kinase-MB/creatine phosphokinase ratio during two interval times was measured.

Results:

In non-ST elevation myocardial infarction patients in the first and second intervals, creatine kinase-MB/creatine phosphokinase ratio was 32.7 and 33.8% higher than the normal laboratory cutoff (positive), respectively, and in the group of unstable angina patients, this index was positive in 31.9 and 30.4% of patients, respectively. There was no significant difference between the mean creatine kinase-MB to creatine phosphokinase index between the patients with non-ST elevation myocardial infarction and unstable angina (p = 0.507). In the first interval, the sensitivity and specificity of this index in differentiating non-ST elevation myocardial infarction from unstable angina were 51.5 and 57.3% (area under the curve = 0.518), respectively. While in the second interval, the sensitivity and specificity of this index were 17.7 and 87.8% (area under the curve = 0.519), respectively. The creatine kinase-MB/creatine phosphokinase delta in the non-ST elevation myocardial infarction group was significantly higher than in patients with unstable angina during different time intervals (p = 0.01).

Conclusion:

According to our results, creatine kinase-MB/creatine phosphokinase index cannot help differentiate the two groups of non-ST elevation myocardial infarction and unstable angina. However, the findings show that higher levels of creatine kinase-MB enzyme and creatine kinase-MB/creatine phosphokinase delta in the early hours, 4–16 h after the onset of pain in non-ST elevation myocardial infarction patients, can be used to differentiate between non-ST elevation myocardial infarction and unstable angina.

Prognostic Value of High-Sensitivity Cardiac Troponin in Women

High-sensitivity cardiac troponin assays have become the gold standard for diagnosing acute and chronic myocardial injury. The detection of troponin levels beyond the 99th percentile is included in the fourth universal definition of myocardial infarction, specifically recommending the use of sex-specific thresholds. Measurable concentrations below the proposed diagnostic thresholds have been shown to inform prognosis in different categories of inpatients and outpatients. However, clinical investigations from the last twenty years have yielded conflicting results regarding the incremental value of using different cut-offs for men and women. While advocates of a sex-specific approach claim it may help reduce gender bias in cardiovascular medicine, particularly in acute coronary syndromes, other groups question the alleged incremental diagnostic and prognostic value of sex-specific thresholds, ultimately asserting that less is more. In the present review, we aimed to synthesize our current understanding of sex-based differences in cardiac troponin levels and to reappraise the available evidence with regard to (i) the prognostic significance of sex-specific diagnostic thresholds of high-sensitivity cardiac troponin assays compared to common cut-offs in both men and women undergoing cardiovascular disease risk assessment, and (ii) the clinical utility of high-sensitivity cardiac troponin assays for cardiovascular disease prevention in women.

Are we any WISER yet? Progress and contemporary need for smart trials to include women in coronary artery disease trials

Despite calls to ensure proportionate representation of both sexes in biomedical research, women continue to be underrepresented in cardiovascular disease (CVD) clinical trials. A comprehensive analysis of seven large suspected ischemic heart disease/coronary artery disease (HD/CAD) clinical trials (PROMISE, ISCHEMIA, CIAO-ISCHEMIA, ORBITA, FAME, FAME 2 and COURAGE trial) provides understanding of contributions to barriers to enrollment of women and leads to strategies to address these barriers. Specifically, in the seven trials, enrollment of women did not exceed 27%, while numerous barriers are evident. Proposed strategies to improve women´s inclusion in clinical trials, include adding reproductive stage/estrogen status, attention to study design inclusion/exclusion criteria using female thresholds, consideration of diagnostic and intervention study design to be inclusive, increasing women and minorities in leadership positions, including sex as a biological variable (SABV) in study design and statistical analysis, and addressing social and race/ethnicity barriers. Dedicated action to actualizing these steps are needed at this time to developing diagnostic and therapeutic strategies resulting in better care and improved outcomes for CVD in women.

Sexual Dimorphism in Cardiovascular Biomarkers: Clinical and Research Implications

Sex-based differences in cardiovascular disease presentation, diagnosis, and response to therapies are well established, but mechanistic understanding and translation to clinical applications are limited. Blood-based biomarkers have become an important tool for interrogating biologic pathways. Understanding sexual dimorphism in the relationship between biomarkers and cardiovascular disease will enhance our insights into cardiovascular disease pathogenesis in women, with potential to translate to improved individualized care for men and women with or at risk for cardiovascular disease. In this review, we examine how biologic sex associates with differential levels of blood-based biomarkers and influences the effect of biomarkers on disease outcomes. We further summarize key differences in blood-based cardiovascular biomarkers along central biologic pathways, including myocardial stretch/injury, inflammation, adipose tissue metabolism, and fibrosis pathways in men versus women. Finally, we present recommendations for leveraging our current knowledge of sex differences in blood-based biomarkers for future research and clinical innovation.

Impact of Sex and Obesity on Echocardiographic Parameters in Children and Adolescents

Subclinical alterations in left ventricular structure and function are detectable in adolescents with hypertension or obesity. However, data on early echocardiographic abnormalities in seemingly healthy children are lacking. Sex differences in cardiac structure and function have been previously reported, but sex-specific reference values are not available. Specifically, the potential interaction of sex and overweight has not been addressed at all. Anthropometric data, blood pressure and exercise tests were obtained in 356 healthy children. Echocardiographic parameters comprised peak early (E) and late (A) mitral inflow Doppler velocities, E/A ratio, tissue Doppler peak velocities of early (e') and late diastolic (a') excursion of mitral/septal annulus and isovolumetric relaxation time (IVRT). Left ventricular mass index (LVMI) and LVMI z-score were calculated. Interaction terms between BMI and sex and stratification by sex were used for analysis. We provide values for echocardiographic parameters for children of two age groups separated by BMI. Overweight/obese children had a significant higher LVMI, lower E/A ratio, higher E/e' ratios and a longer IVRT. For a given BMI in the upper ranges we demonstrated a higher LVMI in girls than in boys, the IVRT extended significantly more in girls than in boys with increasing BMI. There are sex differences in structural and functional echocardiographic parameters in children and adolescents. Our data not only confirms the importance of overweight and obesity, but demonstrates important interactions between sex and overweight. The greater susceptibility of overweight girls toward echocardiographic changes associated with potential long-term functional impairment needs further exploration and follow-up.Trial registration number DRKS00012371; Date 18.08.2017.

Distribution and prognostic value of high-sensitive troponin T measurement in patients with type 2 diabetes without cardiovascular disease

AIM

The objective of this work was to define a value for the 99th percentile of high-sensitive troponin T and to evaluate the prognostic value of this biomarker in a population of patients with type 2 diabetes without a history of cardiovascular disease.

METHODS

In this prospective, observational and analytic study, 482 patients with type 2 diabetes were enrolled. The patients were asymptomatic, with no history of cardiovascular events, renal insufficiency, or inflammatory or systemic disease. As events we considered a combined end point of major adverse cardiovascular events (MACE).

RESULTS

94.9% of the patients had detectable troponin values, 20.7% of the patients had troponin values above the healthy population reference upper threshold (14pg/mL). The 99th percentile value for this patient population was 48pg/mL. Age, sex, the glomerular filtration rate and hypertension were associated with troponin values>14pg/mL. The incidence of MACE was 3.96 per 100 patients/year (p/y) between those with hs-TnT>14pg/mL and 1.07 per 100 p/y between those with hs-TnT≤14pg/mL (HR=3.78 CI95 1.49-9.58; p=0.005).

CONCLUSIONS

The 99th percentile value of troponin T in a population of patients with type 2 diabetes is 3-fold higher than the value proposed by the manufacturer for a healthy population. We also observed a significant difference in the distribution of troponin T values between men and women. This biomarker may be a valuable prognostic factor, since troponin T values above the reference upper threshold were associated with an increase in the risk of cardiovascular events in these patients.

Implications of the ACC/AHA risk score for prediction of heart failure: the Rotterdam Study

BACKGROUND

Despite the growing burden of heart failure (HF), there have been no recommendations for use of any of the primary prevention models in the existing guidelines. HF was also not included as an outcome in the American College of Cardiology/American Heart Association (ACC/AHA) risk score.

METHODS

Among 2743 men and 3646 women aged ≥ 55 years, free of HF, from the population-based Rotterdam Study cohort, 4 Cox models were fitted using the predictors of the ACC/AHA, ARIC and Health-ABC risk scores. Performance of the models for 10-year HF prediction was evaluated. Afterwards, performance and net reclassification improvement (NRI) for adding NT-proBNP to the ACC/AHA model were assessed.

RESULTS

During a median follow-up of 13 years, 429 men and 489 women developed HF. The ARIC model had the highest performance [c-statistic (95% confidence interval [CI]): 0.80 (0.78; 0.83) and 0.80 (0.78; 0.83) in men and women, respectively]. The c-statistic for the ACC/AHA model was 0.76 (0.74; 0.78) in men and 0.77 (0.75; 0.80) in women. Adding NT-proBNP to the ACC/AHA model increased the c-statistic to 0.80 (0.78 to 0.83) in men and 0.81 (0.79 to 0.84) in women. Sensitivity and specificity of the ACC/AHA model did not drastically change after addition of NT-proBNP. NRI(95%CI) was - 23.8% (- 19.2%; - 28.4%) in men and - 27.6% (- 30.7%; - 24.5%) in women for events and 57.9% (54.8%; 61.0%) in men and 52.8% (50.3%; 55.5%) in women for non-events.

CONCLUSIONS

Acceptable performance of the model based on risk factors included in the ACC/AHA model advocates use of this model for prediction of HF risk in primary prevention setting. Addition of NT-proBNP modestly improved the model performance but did not lead to relevant discrimination improvement in clinical risk reclassification.

Evaluation of atherogenic lipoprotein-cholesterol to HDL cholesterol ratio as a prognostic test for ST-segment elevation myocardial infarction

Background: The detectable component of triglyceride-rich lipoproteins (TGRLs), remnant lipoprotein cholesterol (RLP-c), has been proven being correlated with the progression of atherosclerosis and myocardial infarction. However, when taken as a risk predictor, the prognostic and diagnostic potential of RLP-c remains controversial in studies. In this study, we evaluated the hypothesis that atherogenic lipoprotein-cholesterol (AL-c), representing the sum of RLP-c and the sd-LDL-c, to the HDL-c ratio, could represent a better predictive indicator than RLP-c alone in ST-segment elevation myocardial infarction (STEMI). Methods: The 316 consecutive patients suffering from persistent chest discomfort admitted to the Shanghai General Hospital between January 2018 and June 2018 were enrolled. 149 STEMI patients (62% men, mean age 69.6 ± 13.3 years) were included as the study cohort. The AL-c/HDL-c ratio was calculated on admission in a cohort of electrocardiogram-confirmed STEMI patients and compared to other lipid profiles as a predictive indicator. Results: The AL-c/HDL-c ratio was significantly increased in STEMI patients compared with apparently healthy adults (0.93; IQR [0.71-1.18] vs 0.70; IQR [0.45-1.04]; p < 0.001). Gender dependency existed, and the male and female patients had median AL-c/HDL-c ratios of 1.01 and 0.79, respectively (p < 0.001). Compared to RLP-c, the AL-c/HDL-c ratio had a better prognostic value to predict STEMI risk in both sexes (AUC of 0.672 with a sensitivity of 0.794 in males and 0.613 with a sensitivity of 0.684 in females). Conclusions: The AL-c/HDL-c ratio could represent a convenient and sensitive biomarker for screening and predicting STEMI risk.

Salivary biomarkers in cardiovascular disease: An insight into the current evidence

Cardiovascular diseases (CVDs) are the most common cause of mortality worldwide. In acute cardiovascular conditions, time is a crucial player in the outcomes of disease management. Given the ease and noninvasiveness of obtaining saliva, salivary biomarkers may provide a rapid and efficient diagnosis of CVD. Here, we reviewed the published data on the value of salivary molecules for diagnosis of CVD, especially in acute care settings. In this review, we show that some biomarkers such as salivary creatinine kinase myocardial band, C-reactive protein, troponin-1, and myoglobin exhibited promising diagnostic values that were comparable to their serum counterparts. Other molecules were also investigated and showed controversial results, including myeloperoxidase, brain natriuretic peptide, and some oxidative stress markers. Based on our review, we concluded that the clinical use of salivary biomarkers to diagnose CVD is promising; however, it is still in the early stage of development. Further studies are needed to validate these findings, determine cutoff values for diagnosis, and compare them to other established biomarkers currently in clinical use.

Sex Differences in Circulating Biomarkers of Cardiovascular Disease

BACKGROUND

Differences in proteomic profiles between men and women may provide insights into the biological pathways that contribute to known sex differences in cardiovascular disease (CVD).

OBJECTIVES

This study sought to investigate sex differences in circulating biomarkers representative of biological pathways implicated in the development of CVD among Framingham Heart Study participants.

METHODS

The authors measured 71 circulating CVD protein biomarkers in 7,184 participants (54% women, mean age 49 years). Multivariable models were used to evaluate the associations of sex, menopause, and hormone status with biomarkers. Cox models were used to examine whether sex modified the association of biomarkers with incident CVD.

RESULTS

Of 71 biomarkers examined, 61 (86%) differed significantly between men and women, of which 37 were higher in women (including adipokines and inflammatory markers such as leptin and C-reactive protein), and 24 were higher in men (including fibrosis and platelet markers such as MMP-8 (matrix metalloproteinase-8) and TIMP-1 (tissue inhibitor of metalloproteinases 1); false discovery rate q < 0.05 for all). Sex differences in biomarker profiles were most pronounced between pre-menopausal women versus men, with attenuated sex differences among post-menopausal women not taking hormone replacement therapy. Sex modified the association of specific biomarkers with incident CVD, including CD14 and apolipoprotein B (p_interaction <0.05 for all).

CONCLUSIONS

In a predominantly Caucasian population, the authors identified widespread sex differences in circulating biomarkers that reflect distinct pathways implicated in CVD, including inflammation, adiposity, fibrosis, and platelet homeostasis. Menopause and hormone status accounted for some, but not all, of the observed sex differences. Further investigation into factors underlying sex-based differences may provide mechanistic insight into CVD development.

Gender-Specific Predictive Markers of Poor Prognosis for Patients with Acute Myocardial Infarction During a 6-Month Follow-up

Mounting evidence indicates the impact of gender difference on the assessment, treatment, and outcome of patients with acute myocardial infarction (AMI). However, gender-specific prognostic markers of AMI are still lacking. The present study aimed to investigate gender-specific markers of poor prognosis (all-cause mortality or readmission) in a cohort of AMI patients followed up for 6 months. Compared with males (n = 157), females (n = 40) were older and more frequent with previous medical history of hypertension and diabetes mellitus. During the 6-month follow-up, BUN ≥ 7.73 mM, myoglobin ≥ 705.8 ng/mL, and Killip classification 2-4 were identified as the independent predictors of poor prognosis for male AMI patients, while D-dimer ≥ 0.43 mg/L as an independent predictor of poor prognosis in female AMI patients. In conclusion, our data suggest that prognostic markers for AMI patients may differ according to genders. Gender-specific prognostic markers may be useful to guide the risk stratification, clinical therapy, and medications for AMI patients.

Direct Comparison of Cardiac Troponin T and I Using a Uniform and a Sex-Specific Approach in the Detection of Functionally Relevant Coronary Artery Disease

BACKGROUND

We aimed to directly compare high-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity cardiac troponin T (hs-cTnT) in the detection of functionally relevant coronary artery disease (fCAD).

METHODS

Consecutive patients referred with clinical suspicion of fCAD and no structural heart disease other than coronary artery disease were included. The presence of fCAD was based on rest/stress myocardial perfusion single-photon emission computed tomography/computed tomography and coronary angiography. hs-cTnI and hs-cTnT concentrations were measured in a blinded fashion. Diagnostic accuracy was quantified using the area under the ROC curve (AUC) and evaluated both for uniform use in all patients and for sex-specific use in women and men separately. The prognostic end point was major adverse cardiac events (MACEs; cardiovascular death or myocardial infarction) within 2 years. For the prognostic performance, we used a multivariable model comparison with the Akaike information criterion (AIC).

RESULTS

fCAD was detected in 613 of 2062 patients (29.7%) overall, 112 of 664 of women (16.9%), and 501 of 1398 of men (35.8%). hs-cTnI and hs-cTnT had comparable diagnostic accuracy when assessed for uniform use in all patients (AUC, 0.68 vs 0.66; P = 0.107) and separately in women (AUC, 0.68 vs 0.63; P = 0.068) and men (AUC, 0.65 vs 0.64; P = 0.475). However, women required lower rule-out cutoffs to achieve high sensitivity, and men needed higher rule-in cutoffs to achieve high specificity. hs-cTnI and hs-cTnT were strongly and independently associated with MACE within 2 years (P &lt; 0.001), with comparable prognostic accuracies by the AIC.

CONCLUSIONS

hs-cTnI and hs-cTnT provide moderate and comparable diagnostic accuracy. Sex-specific cutoffs may be preferred. The prognostic utility of both troponins is comparable.

Heart Failure with Reduced Ejection Fraction in Women: Epidemiology, Outcomes, and Treatment

There are millions of people affected by heart failure with reduced ejection fraction (HFrEF) as diagnosed with ejection fraction 40% or less by imaging. Established therapies have been proven through clinical trials on lifestyle interventions, medications, and devices for HFrEF to improve quality of life, heart function, and survival. Although there are more men than women suffering with HFrEF, there are no prospectively proven, sex-specific guideline therapies because women have been underrepresented in clinical trials. Current recommendations for medications in women with HFrEF are described in this article.

Cerebrospinal Fluid Total Protein Reference Intervals Derived from 20 Years of Patient Data

BACKGROUND

Reference intervals are vital for interpretation of laboratory results. Many existing reference intervals for cerebrospinal fluid total protein (CSF-TP) are derived from old literature because of the invasive nature of sampling. The objective of this study was to determine reference intervals for CSF-TP using available patient data.

METHODS

Twenty years of hospital database information was mined for previously reported CSF-TP results. Associated demographic, laboratory, and clinical diagnosis (International Classification of Diseases 9/10 codes) details were extracted. CSF-TP results included 3 different analytical platforms: the Siemens Vista 1500, Beckman Lx20, and Roche Hitachi 917. From an initial data set of 19591 samples, the following exclusion criteria were applied: incomplete data, white blood cells (WBCs) &gt;5 × 106/L, red blood cells (RBCs) &gt;50 × 106/L, and glucose &lt;2.5 mmol/L. Patient charts were reviewed in detail to exclude 60 different conditions for which increases in CSF-TP would be expected. A total of 6068 samples were included; 63% of the samples were from females. Continuous reference intervals were determined using quantile regression. Age- and sex-partitioned intervals were established using the quantile regression equation and splitting age-groups into 5-year bins.

RESULTS

CSF-TP showed a marked age dependence, and males had significantly higher CSF-TP than females across all ages. CSF-TP results from the 3 different instruments and manufacturers showed small (approximately 0.04 g/L), but statistically significant, differences. CSF-TP showed weak, but again statistically significant, correlation with WBC and RBC but was independent of serum total protein and creatinine.

CONCLUSIONS

The age dependence of CSF-TP supports that age-partitioned reference intervals will be more accurate than a single cutoff, particularly in patients with advancing age.

Poor acute outcome in congestive heart failure is associated with increases in the plasma static oxidation-reduction potentials (sORP) in men but not in women

OBJECTIVES

In congestive heart failure (CHF), men are younger, more likely to have reduced ejection fraction (HF-rEF), and to be diabetic compared to women. Despite this, sex differences in oxidative stress have yet to be explored in CHF.

METHODS

Data from 67 males and 63 females hospitalized for CHF were collected. Static oxidation-reduction potential (sORP), a relative indicator of oxidative stress, and capacity ORP (icORP), a relative indicator of antioxidant capacity, were measured from plasma samples. We examined whether sex modified the relationship between ORP and hospital discharge disposition (poor outcome: death, hospice), along with other demographics, medications, and diagnostic parameters.

RESULTS

Males with poor outcomes had higher sORP and icORP values than females (P < 0.05). For those with a good outcome, there were no differences between the sexes (P > 0.05). Males were younger and more likely to have HF-rEF and diabetes. Controlling for these variables did not account for the sex differences in ORP measures. Regardless of sex, higher creatinine was related to higher sORP and icORP, while lower magnesium and potassium were related to higher sORP and icORP, respectively.

DISCUSSION

Increases in sORP during CHF are partially affected by sex and acute outcomes, but are also related to variables without sexual biases.

Assessing and Modifying Coronary Artery Disease Risk in Women

OPINION STATEMENT

Despite continued advances in the field, cardiovascular disease remains the leading cause of death in women in the USA with an annual mortality rate that has remained higher for women as compared to men. The factors leading to this sex difference remain incompletely understood. Likely contributors include atypical symptoms at presentation and lack of recognition of cardiovascular risk by women and their providers alike. In addition, women have a higher burden of comorbidities at the time of disease diagnosis and can have differential pathophysiological mechanisms of their acute events. Women also can develop unique cardiovascular risk factors such as preeclampsia and hypertensive disorders of pregnancy. As a result, when women present with symptoms, even atypical, healthcare providers should increase their index level of suspicion for cardiovascular disease. Even after diagnosis, women are less likely to receive guideline-directed medical therapies and be referred for coronary angiography or cardiac rehabilitation. Thus, greater awareness of and research into the aspects of coronary disease that remain unique to women is critical, as women presenting with coronary disease continue to receive disparate care as compared to men. Improvements in awareness and care and new research avenues may reduce the incidence and complications of cardiovascular disease among women.

Cardiac Biomarkers and the Diagnosis of Myocardial Infarction in Women

PURPOSE OF REVIEW

Women with suspected acute coronary syndrome are less likely to undergo investigation or receive treatment than men, and women consistently have poorer outcomes. This review summarises how the latest development in cardiac biomarkers could improve both diagnosis and outcomes in women.

RECENT FINDINGS

Novel high-sensitivity cardiac troponin assays have identified differences in the reference range and therefore diagnostic threshold for myocardial infarction in men and women. These differences are present across multiple populations with different ethnic backgrounds and for a range of assays. The use of a uniform threshold for cardiac troponin does not provide equivalent prediction in men and women, with lower thresholds needed for women to provide comparable risk stratification. Sex differences in cardiac troponin concentrations are not widely recognised in clinical practice and may be contributing to the under-diagnosis of myocardial infarction in women and discrepancies in patient care and outcomes.

Differentiating heart failure phenotypes using sex-specific transcriptomic and proteomic biomarker panels

Aims

Heart failure with preserved ejection fraction (HFpEF) accounts for 30–50% of patients with heart failure (HF). A major obstacle in HF management is the difficulty in differentiating between HFpEF and heart failure with reduced ejection fraction (HFrEF) using conventional clinical and laboratory investigations. The aim of this study is to develop robust transcriptomic and proteomic biomarker signatures that can differentiate HFpEF from HFrEF.

Methods and results

A total of 210 HF patients were recruited in participating institutions from the Alberta HEART study. An expert clinical adjudicating panel differentiated between patients with HFpEF and HFrEF. The discovery cohort consisted of 61 patients, and the replication cohort consisted of 70 patients. Transcriptomic and proteomic data were analysed to find panels of differentiating HFpEF from HFrEF. In the discovery cohort, a 22‐transcript panel was found to differentiate HFpEF from HFrEF in male patients with a cross‐validation AUC of 0.74, as compared with 0.70 for N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) in those same patients. An ensemble of the transcript panel and NT‐pro‐BNP yielded a cross‐validation AUC of 0.80. This performance improvement was also observed in the replication cohort. An ensemble of the transcriptomic panel with NT‐proBNP produced a replication AUC of 0.90, as compared with 0.74 for NT‐proBNP alone and 0.73 for the transcriptomic panel.

Conclusions

We have identified a male‐specific transcriptomic biomarker panel that can differentiate between HFpEF and HFrEF. These biosignatures could be further replicated on other patients and potentially be developed into a blood test for better management of HF patients.

A prospective assessment of cardiac biomarkers for hemodynamic stress and necrosis and the risk of falls among older people: the ActiFE study

Falls are related to a complex interaction of risk factors. We examined if cardiac biomarkers for hemodynamic stress (N-terminal pro Brain Natriuretic Peptide-NT-proBNP), and for necrosis [high sensitive (hs) cardiac troponins T (cTnT) and I (cTnI)] are associated with falls in older people. Biomarkers were measured at baseline in a cohort of 1506 community-dwelling adults ≥65 years. Falls were assessed prospectively in a falls calendar (median 370 days). Cox-proportional hazards models evaluated the association of each biomarker with the incidence of the first fall accounting for established confounders. We observed 430 incident falls among 1327 participants and an effect modification by sex for all biomarkers. In multivariable analyses among men a one unit increment of log-transformed hs-cTnI was associated with a hazard ratio (HR) of 1.26 (95 % CI 1.04, 1.53). Men with hs-cTnT ≥ 14 ng/L had a HR of 1.74 (95 % CI 1.15, 2.61) compared to those with undetectable hs-cTnT levels. In women cTn were not associated with falls. We did not detect an association between NT-proBNP and the risk of fall. Our results suggest that cardiac troponins may not only identify subjects at risk for cardiovascular diseases, but also help to understand the underlying complex pathophysiology of falls.

Multimarker proteomic profiling for the prediction of cardiovascular mortality in patients with chronic heart failure

Risk stratification of patients with systolic chronic heart failure (HF) is critical to better identify those who may benefit from invasive therapeutic strategies such as cardiac transplantation. Proteomics has been used to provide prognostic information in various diseases. Our aim was to investigate the potential value of plasma proteomic profiling for risk stratification in HF. A proteomic profiling using surface enhanced laser desorption ionization - time of flight - mass spectrometry was performed in a case/control discovery population of 198 patients with systolic HF (left ventricular ejection fraction <45%): 99 patients who died from cardiovascular cause within 3 years and 99 patients alive at 3 years. Proteomic scores predicting cardiovascular death were developed using 3 regression methods: support vector machine, sparse partial least square discriminant analysis, and lasso logistic regression. Forty two ion m/z peaks were differentially intense between cases and controls in the discovery population and were used to develop proteomic scores. In the validation population, score levels were higher in patients who subsequently died within 3 years. Similar areas under the curves (0.66 - 0.68) were observed for the 3 methods. After adjustment on confounders, proteomic scores remained significantly associated with cardiovascular mortality. Use of the proteomic scores allowed a significant improvement in discrimination of HF patients as determined by integrated discrimination improvement and net reclassification improvement indexes. In conclusion, proteomic analysis of plasma proteins may help to improve risk prediction in HF patients.

Biomarkers of cardiovascular disease risk in women

Cardiovascular disease (CVD), including coronary heart disease and stroke, is the leading cause of death among U.S. women and men. Established cardiovascular risk factors such as smoking, diabetes, hypertension, and elevated total cholesterol, and risk prediction models based on such factors, perform well but do not perfectly predict future risk of CVD. Thus, there has been much recent interest among cardiovascular researchers in identifying novel biomarkers to aid in risk prediction. Such markers include alternative lipids, B-type natriuretic peptides, high-sensitivity troponin, coronary artery calcium, and genetic markers. This article reviews the role of traditional cardiovascular risk factors, risk prediction tools, and selected novel biomarkers and other exposures in predicting risk of developing CVD in women. The predictive role of novel cardiovascular biomarkers for women in primary prevention settings requires additional study, as does the diagnostic and prognostic utility of cardiac troponins for acute coronary syndromes in clinical settings. Sex differences in the clinical expression and physiology of metabolic syndrome may have implications for cardiovascular outcomes. Consideration of exposures that are unique to, or more prevalent in, women may also help to refine cardiovascular risk estimates in this group.

High sensitivity cardiac troponin assays in the clinical laboratories

Immunoassays measuring cardiac troponins I or T have become firmly established as critical tools for diagnosing acute myocardial infarction. While most contemporary assays provide adequate diagnostic performance, the increased sensitivity and precision of the new, high sensitivity assays that have already been introduced into clinical practice, provide the potential to further shorten intervals between blood draws or the time needed to detect the first significant troponin elevation. In addition to the relatively modest benefits at the diagnostic end, the high sensitivity assays and the investigational ultrasensitive cardiac troponin assays offer improvements for predicting major adverse cardiovascular events, development of heart failure or transition to end-stage kidney disease. These novel high sensitivity assays can measure troponin concentrations in 50%–100% of healthy individuals and therefore allow for the distribution of troponin values within a healthy cohort to be measured, patient’s baseline troponin levels to be monitored, and clinicians to be alerted of deteriorating cardiorenal conditions. We envisage that the high sensitivity assays will become important tools for predicting each patient’s risk of future adverse events and for guiding and monitoring corresponding adjustments of preventative therapeutic interventions.

Sex-specific associations of established and emerging cardiac biomarkers with all-cause mortality in older adults: the ActiFE study

BACKGROUND

N-terminal pro B-type natriuretic peptide (NT-proBNP) has strong prognostic value for all-cause mortality in the general population. High-sensitivity assays now allow detection of cardiac troponins even in asymptomatic populations. We examined the association between NT-proBNP, high-sensitivity cardiac troponin T (hs-cTnT), and hs-cTnI and all-cause mortality in older adults.

METHODS

We conducted a longitudinal cohort study [Activity and Function in the Elderly in Ulm (ActiFE Ulm)] including 1506 community-dwelling adults ≥65 years old with NT-proBNP, hs-cTnT, and hs-cTnI measured at baseline. We evaluated the associations between log-transformed biomarker concentrations and 4-year total mortality, accounting for possible confounders, with Cox proportional hazards models.

RESULTS

We observed 125 deaths among 1422 participants (median follow-up 4 years). We detected effect modification by sex for all biomarkers (all P values <0.05) expressed as hazard ratio (HR) for death per 1-unit increment of ln(biomarker concentration) in women (n = 618, 37 deaths) compared with men (n = 804, 88 deaths): HR 2.97 (95% CI 2.04-4.33) vs 1.73 (1.40-2.13) for NT-proBNP; 3.67 (2.31-5.81) vs 2.15 (1.61-2.87) for hs-cTnT; and 3.32 (2.13-5.18) vs 1.92 (1.55-2.38) for hs-cTnI. Among 777 participants with undetectable hs-cTnT (<5 ng/L), hs-cTnI remained associated with all-cause mortality in age- and sex-adjusted analysis.

CONCLUSIONS

NT-proBNP, hs-cTnT, and hs-cTnI were independently associated with all-cause mortality in older adults. The strength of these associations varied between men and women, emphasizing the need for additional sex-specific research among older people.

Utility of salivary biomarkers for demonstrating acute myocardial infarction

The comparative utility of serum and saliva as diagnostic fluids for identifying biomarkers of acute myocardial infarction (AMI) was investigated. The goal was to determine if salivary biomarkers could facilitate a screening diagnosis of AMI, especially in cases of non-ST elevation MI (NSTEMI), since these cases are not readily identified by electrocardiogram (ECG). Serum and unstimulated whole saliva (UWS) collected from 92 AMI patients within 48 hours of chest pain onset and 105 asymptomatic healthy control individuals were assayed for 13 proteins relevant to cardiovascular disease, by Beadlyte technology (Luminex(®)) and enzyme immunoassays. Data were analyzed with concentration cut-points, ECG findings, logistic regression (LR) (adjusted for matching for age, gender, race, smoking, number of teeth, and oral health status), and classification and regression tree (CART) analysis. A sensitivity analysis was conducted by repetition of the CART analysis in 58 cases and 58 controls, each matched by age and gender. Serum biomarkers demonstrated AMI sensitivity and specificity superior to that of saliva, as determined by LR and CART. The predominant discriminators in serum by LR were troponin I (TnI), B-type natriuretic peptide (BNP), and creatine kinase-MB (CK-MB), and TnI and BNP by CART. In saliva, LR identified C-reactive protein (CRP) as the biomarker most predictive of AMI. A combination of smoking tobacco, UWS CRP, CK-MB, sCD40 ligand, gender, and number of teeth identified AMI in the CART decision trees. When ECG findings, salivary biomarkers, and confounders were included, AMI was predicted with 80.0% sensitivity and 100% specificity. These analyses support the potential utility of salivary biomarker measurements used with ECG for the identification of AMI. Thus, saliva-based tests may provide additional diagnostic screening information in the clinical course for patients suspected of having an AMI.