Evidence of cardiac myolysis in severe nonischemic heart failure and the potential role of increased wall strain

Pathophysiological mechanisms underlying increased circulating cardiac troponin in noncardiac surgery: a narrative review

Assay-specific increases in circulating cardiac troponin are observed in 20-40% of patients after noncardiac surgery, depending on patient age, type of surgery, and comorbidities. Increased cardiac troponin is consistently associated with excess morbidity and mortality after noncardiac surgery. Despite these findings, the underlying mechanisms are unclear. The majority of interventional trials have been designed on the premise that ischaemic cardiac disease drives elevated perioperative cardiac troponin concentrations. We consider data showing that elevated circulating cardiac troponin after surgery could be a nonspecific marker of cardiomyocyte stress. Elevated concentrations of circulating cardiac troponin could reflect coordinated pathological processes underpinning organ injury that are not necessarily caused by ischaemia. Laboratory studies suggest that matching of coronary artery autoregulation and myocardial perfusion-contraction coupling limit the impact of systemic haemodynamic changes in the myocardium, and that type 2 ischaemia might not be the likeliest explanation for cardiac troponin elevation in noncardiac surgery. The perioperative period triggers multiple pathological mechanisms that might cause cardiac troponin to cross the sarcolemma. A two-hit model involving two or more triggers including systemic inflammation, haemodynamic strain, adrenergic stress, and autonomic dysfunction might exacerbate or initiate acute myocardial injury directly in the absence of cell death. Consideration of these diverse mechanisms is pivotal for the design and interpretation of interventional perioperative trials.

Clinical Interpretation of Serum Troponin in the Era of High-Sensitivity Testing

Cardiac troponin (Tn) plays a central role in the evaluation of patients with angina presenting with acute coronary syndrome. The advent of high-sensitivity assays has improved the analytic sensitivity and precision of serum Tn measurement, but this advancement has come at the cost of poorer specificity. The role of clinical judgment is of heightened importance because, more so than ever, the interpretation of serum Tn elevation hinges on the careful integration of findings from electrocardiographic, echocardiographic, physical exam, interview, and other imaging and laboratory data to formulate a weighted differential diagnosis. A thorough understanding of the epidemiology, mechanisms, and prognostic implications of Tn elevations in each cardiac and non-cardiac etiology allows the clinician to better distinguish between presentations of myocardial ischemia and myocardial injury-an important discernment to make, as the treatment of acute coronary syndrome is vastly different from the workup and management of myocardial injury and should be directed at the underlying cause.

Assessment of Troponin I Levels as a Predictor of Mortality in Acute Decompensated Heart Failure

BACKGROUND

Acute decompensated heart failure (ADHF) is a highly prevalent diagnosis in the emergency department and is associated with high morbidity and mortality. As mortality remains high even in patients discharged from the emergency, it becomes mandatory to identify markers predictive of mortality in order to guide the disposition of such patients. No literature is available on the prognostic significance of Troponin I in ADHF patients in an emergency setting from an Indian standpoint.

OBJECTIVES

This study was aimed at identifying the ability of Troponin I levels at presentation to predict one-month mortality in patients with ADHF.

METHODS

The study was conducted in the emergency department of a tertiary healthcare center in north India. Serum cardiac Troponin I (cTnI) levels at presentation were assayed in 101 patients and a one-month follow-up was done.

RESULTS

cTnI levels were > 0.02 ng/mL in 51 patients (50.5%). ROC analysis showed an accuracy of 63% in predicting mortality (p < 0.05). Univariate and multivariate analysis showed an OR of 2.58 and 2.74, respectively (p - 0.037 and 0.047, respectively), suggesting cTnI to be a significant predictor of mortality in ADHF. N-terminal proBNP (NT-proBNP) (OR - 2.09; p - 0.229) and left ventricular ejection fraction (OR - 2.01; p - 0.157) were not found to be significant predictors of mortality on regression analysis.

CONCLUSION

cTnI levels at presentation are a significant predictor of short-term mortality in ADHF and can be used in an emergency setting to guide treatment, disposition, and follow-up plans of these patients.

Acute heart failure in elderly patients admitted to the emergency department with acute dyspnea: a multimarker approach diagnostic study

BACKGROUND AND IMPORTANCE

Diagnosing acute heart failure (AHF) is difficult in elderly patients presenting with acute dyspnea to the emergency department.

OBJECTIVES

To assess the diagnostic accuracy of NT-proBNP, high-sensitivity cardiac troponin-I (Hs-cTnI), soluble ST2 (ST2), galectin-3 and CD146 alone and in combination for diagnosing AHF in elderly patients presenting with acute dyspnea to the emergency department.

DESIGN, SETTINGS AND PARTICIPANTS

This was a prospective, multicenter study performed between September 2016 and January 2020, including elderly patients presenting with acute dyspnea to the emergency department of 6 French hospitals.

INTERVENTION

Measurement of NT-proBNP, hs-cTnI, ST2, galectin-3 and CD146.

OUTCOME MEASURE AND ANALYSIS

The reference standard, AHF, was adjudicated by two independent physicians based on ED and hospitalization clinical, biological (excluding biomarkers), radiological and echocardiography data (performed by a cardiologist in the cardiology department specifically for this study). Three exploratory methods (two using a cross-sectional approach with logistic regression and counting all biomarker combinations, and one using a sequential approach with gray zone optimizations) were applied to create comprehensive combinations of the 5 biomarkers for measuring diagnostic accuracy.

MAIN RESULTS

Two hundred thirty-eight patients (median age of 85 years, IQR = 8) were analyzed, and 110 (46%) were diagnosed with AHF. The accuracies of NT-proBNP, CD146, hs-cTnI, galectin-3, and ST2 were 0.72 [95% confidence interval (CI) 0.66-0.77], 0.63 (95% CI 0.57-0.69), 0.59 (95% CI 0.53-0.65), 0.55 (95% CI 0.49-0.61) and 0.51 (95% CI 0.45-0.57), respectively. Regardless of the approach used or how the 5 biomarkers were combined, the best accuracy for diagnosing AHF (0.73, 95% CI 0.67-0.78) did not differ from that of NT-proBNP alone.

CONCLUSION

In this study, NT-proBNP alone exhibited the best diagnostic accuracy for diagnosing AHF in elderly patients presenting with acute dyspnea to the emergency departments. None of the other biomarkers alone or combined improved the accuracy compared to NT-proBNP, which is the only biomarker to use in this setting.

Kinetics of cardiac troponin and other biomarkers in patients with ST elevation myocardial infarction

Objective

To examine changes in concentration, time-to-peak and the ensuing half-life of cardiac biomarkers in patients with myocardial infarction.

Methods

Blood sampling was performed every third hour within 24 h after percutaneous coronary intervention (PCI) on a cohort of patients with ST elevation myocardial infarction. Cardiac troponin (cTn) was measured by the Dimension Vista, Vitros, Atellica, and Alinity high-sensitivity (hs) cTnI assays, and the Elecsys hs-cTnT assay. Further, creatine kinase (CK), myoglobin, creatine kinase MB (CKMB) and other biomarkers were analyzed.

Results

A total of 36 patients completed blood sampling (median age 60 years, IQR 56.4-66.5 years; seven women, 19.4%). Hs-cTnI measured by the Vitros assay was the first hs-cTn to peak at 9.1 h (95%-CI 6.2-10.1) after PCI and 11.7 h (95%-CI 10.4-14.8) after symptoms onset. There were no notable differences between hs-cTn assays in regard to time-to-peak. Also, Vitros hs-cTnI reached the highest median ratio of concentration to upper reference level of nearly 2,000. The median half-life from peak concentration ranged from 7.6 h for myoglobin (CI 6.8-8.6) to 17.8 h for CK (CI 6.8-8.6). For hs-cTn assays the median T½ ranged from 12.4 h for the Vista hs-cTnI assay (95%-CI 11.0-14.1 h) to 17.3 h for the Elecsys hs-cTnT (95%-CI 14.9-20.8 h).

Conclusions

This study updates knowledge on the kinetics of cardiac biomarkers in current clinical use. There was no notable difference in trajectories, time-to-peak or half-life between hs-cTn assays.

Relationship Between Albumin-Corrected Anion Gap and Mortality in Hospitalized Heart Failure Patients

BACKGROUND

Heart failure (HF) is a disease with high morbidity and mortality. Despite the efforts to reduce mortality rates through medical progress, it is necessary to develop markers to identify critically ill patients. In our study, we aimed to investigate the relationship between albumin-corrected anion gap (ACAG) and mortality in hospitalized patients with HF.

METHODOLOGY

We performed a retrospective study that included patients with HF hospitalized in the Erzurum City Hospital between 2015 and 2022. The basal clinical, hematological, and biochemical findings of the patients were obtained from the electronic medical records. ACAG was calculated. The date and causes of death of the patients were searched and recorded through the Republic of Türkiye Ministry of Health Death Notification System (ÖBYS) and Central Population Administration System (MERNIS). Thus, the relationship between ACAG and mortality in hospitalized patients with HF was evaluated.

RESULTS

A total of 205 patients hospitalized for HF were included in the study. The mean age of all people in this study was 71.8 ± 10.7 years. A total of 104 (50.7%) of the patients included in the study were women. The mean left ventricular ejection fraction was 47.2 ± 13.6%. The mean follow-up period of the entire population was 76.5 ± 18.9 months. The mortality rate was 11.7% (24 patients). Serum anion gap (SAG) and ACAG were significantly higher in the group with death outcomes (p = 0.043 and p = 0.012, respectively). Cox regression analysis showed that ACAG was an independent predictor of HF mortality (p = 0.003). ACAG area under the curve was 0.773 (95% CI 0.634 - 0.914), the cut-off was 13, sensitivity was 75%, and specificity was 75.9% (p = 0.002).

CONCLUSION

Statistical analysis showed a meaningful connection between an increase in ACAG and mortality in hospitalized patients with HF. Consequently, ACAG can be used as an independent predictor of mortality in patients with HF.

Deciphering the Dilemma: Anticoagulation for Heart Failure With Preserved Ejection Fraction (HFpEF)

Impairment in ventricular relaxation and preserved left ventricular ejection fraction are the two main features of heart failure with preserved ejection fraction (HFpEF) a difficult clinical condition. Therapeutic choices for HFpEF patients are still scarce despite its rising frequency and negative effects on morbidity and mortality, necessitating creative methods to enhance results. The increased thromboembolic risk seen in these individuals raises questions about the relevance of anticoagulation in the therapy of HFpEF. Although anticoagulation has been shown to be beneficial in heart failure with decreased ejection fraction (HFrEF) and other high-risk cardiovascular disorders, its efficacy and safety in HFpEF present a challenging therapeutic challenge. Anticoagulants have been the subject of clinical trials in HFpEF, but the results have been conflicting, giving clinicians only a little information with which to make decisions. The decision-making process is made more difficult by worries about potential bleeding hazards, particularly in susceptible elderly HFpEF patients with other comorbidities. The link between heart failure and anticoagulant medication in HFpEF is thoroughly analyzed in this narrative review. In HFpEF, cardiac fibrosis and endothelial dysfunction create a prothrombotic milieu, as is highlighted in this passage. Also covered are recent developments in innovative biomarker research and cutting-edge imaging techniques, which may provide ways to spot HFpEF patients who might benefit from anticoagulation. This therapeutic conundrum may be resolved by using precision medicine strategies based on risk classification and individualized therapy choices. This review emphasizes the need for more research to establish the best use of anticoagulation in HFpEF within the framework of personalized therapy and shared decision-making. To successfully manage thromboembolic risk and reduce bleeding consequences in HFpEF patients, it is essential to perform well-designed clinical studies and advance our understanding of the pathophysiology of HFpEF. These developments may ultimately improve the prognosis and quality of life for people who suffer from this difficult and mysterious ailment.

Case report: Acute toxic myocardial damage caused by 5-fluorouracil—from enigma to success

Considering the pandemic of both cardiovascular diseases and oncological diseases, there is an increasing need for the use of chemotherapy, which through various pathophysiological mechanisms leads to damage to heart function. Cardio toxicity of chemotherapy drugs can manifest itself in a variety of clinical manifestations, which is why establishing a valid diagnosis is a real mystery for clinicians. Acute systolic heart failure (AHF) due to the use of 5-fluorouracil (5-FU) is a rare occurrence if it is not associated with myocardial infarction, myocarditis or Takotsubo cardiomyopathy. Therefore, we decided to present a case of an 52-year-old male who was diagnosed with stage IV RAS wild-type adenocarcinoma of the rectum and in whom the direct toxic effect 5-FU is the main reason for the appearance of toxic cardiomyopathy.

Impact of Cardiac Troponin Elevation on Mortality of Patients with Acute Heart Failure: Insights from the Korea Acute Heart Failure (KorAHF) Registry

We aimed to conduct the largest study evaluating the impact of cardiac troponin (TnI) status on mid- and long-term mortality in patients admitted for acute heart failure (AHF) as compared between patients with ischemic (IHF) vs. non-ischemic heart failure (non-IHF). Among 5625 patients from the Korea Acute Heart Failure (KorAHF) registry, 4396 eligible patients with TnI measurement were analyzed. The patients were included on admission with the diagnosis of AHF, and TnI level was measured on the day of admission. A TnI value of <0.05 ng/mL was considered normal. The patients were divided into four groups according to the etiology of heart failure and the status of TnI: non-IHF with normal TnI (n = 1009) vs. non-IHF with elevated TnI (n = 1665) vs. IHF with normal TnI (n = 258) vs. IHF with elevated TnI (n = 1464). The primary outcome was death from all causes according to the etiology (non-IHF vs. IHF) and TnI elevation during the entire follow-up period of 784 days (IQR 446−1116). Elevation of TnI was observed in 71.2% of all patients with AHF. Patients with IHF had higher all-cause mortality compared to those with non-IHF. Elevated TnI was associated with higher 90-day and post-90-day mortality in the non-IHF group. IHF as compared to non-IHF and elevation of TnI were independent predictors of mortality also in the adjustment analysis. In the IHF group, however, elevated TnI had a higher mortality with only 90-day follow-up (18.6% vs. 25.9%, log-rank p < 0.001), not in the post-90-day follow-up (31.1% vs. 32.5%, log-rank p = 0.799). In conclusion, elevated TnI in patients with heart failure is associated with increased all-cause mortality regardless of the etiology of HF. Elevation of TnI was associated to a higher post-90 day mortality in patients with non-IHF but not in patients with IHF.

Cardiac troponins and adverse outcomes in European patients with atrial fibrillation: A report from the ESC-EHRA EORP atrial fibrillation general long-term registry

BACKGROUND

Cardiac troponins (cTn) have been reported to be predictors for adverse outcomes in atrial fibrillation (AF), patients, but their actual use is still unclear.

AIM

To assess the factors associated with cTn testing in routine practice and evaluate the association with outcomes.

METHODS

Patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry were stratified into 3 groups according to cTn levels as (i) cTn not tested, (ii) cTn in range (≤99th percentile), (iii) cTn elevated (>99th percentile). The composite outcome of any thromboembolism /any acute coronary syndrome/cardiovascular (CV) death, defined as Major Adverse Cardiovascular Events (MACE) and all-cause death were the main endpoints.

RESULTS

Among 10 445 AF patients (median age 71 years, 40.3% females) cTn were tested in 2834 (27.1%). cTn was elevated in 904/2834 (31.9%) and in-range in 1930/2834 (68.1%) patients. Female sex, in-hospital enrollment, first-detected AF, CV risk factors, history of coronary artery disease, and atypical AF symptoms were independently associated with cTn testing. Elevated cTn were independently associated with a higher risk for MACE (Model 1, hazard ratio [HR] 1.74, 95% confidence interval [CI] 1.40-2.16, Model 2, HR 1.62, 95% CI 1.28-2.05; Model 3 HR 1.76, 95% CI 1.37-2.26) and all-cause death (Model 1, HR 1.45, 95% CI 1.21-1.74; Model 2, HR 1.36, 95% CI 1.12-1.66; Model 3, HR 1.38, 95% CI 1.12-1.71).

CONCLUSIONS

Elevated cTn levels were associated with an increased risk of all-cause mortality and adverse CV events. Clinical factors that might enhance the need to rule out CAD were associated with cTn testing.

Cardiac troponin and defining myocardial infarction

The 4th Universal Definition of Myocardial Infarction has stimulated considerable debate since its publication in 2018. The intention was to define the types of myocardial injury through the lens of their underpinning pathophysiology. In this review, we discuss how the 4th Universal Definition of Myocardial Infarction defines infarction and injury and the necessary pragmatic adjustments that appear in clinical guidelines to maximize triage of real-world patients.

Myocardial ischemia and coronary disease in heart failure

Heart failure is a complex clinical syndrome and represents the final path of numerous heart diseases. Coronary artery disease is recognized as the primary risk factor for heart failure development, being the main etiological factor in more than 50% of heart failure patients in North America and Europe. Regardless of overt coronary artery disease, myocardial ischemia is a common finding in failing hearts, likely due to structural or functional coronary circulation alterations. Ischemia is a self-propagating process which irreversibly impairs the cardiac function and negatively impacts prognosis. Thus, a better and thorough understanding of myocardial ischemia pathophysiology in heart failure would likely lead to significantly improved outcomes in these patients. This review aims to describe the mechanisms of myocardial ischemia and coronary artery disease in heart failure, focusing on coronary circulation dysfunctions due to increased parietal stress or non-obstructive coronary disease, and discussing the association and management of coronary artery disease in patients with heart failure.

Type 2 myocardial infarction: is it a geriatric syndrome?

Type 2 myocardial infarctions (T2-MI) is a type of necrosis that results from reduced oxygen supply and/or increased demand secondary to other causes unrelated to acute coronary atherothrombosis. The development and implementation of sensitive and high-sensitivity cardiac necrosis marker and the age-related increase of comorbidity lead to a boost of the frequency of T2-MI. T2-MI is often a complication of a high degree of clinical frailty in older adults, emerging as a "geriatric syndrome". Age-related non-cardiovascular causes may be the triggering factors and are strongly associated with the diagnosis, treatment, and prognosis of T2-MI. To date, there are no guidelines on management of this pathology in advancing age. Patient-centered approach and comprehensive geriatric assessment play a key role in the diagnosis, therapy and prognosis of geriatric patients with T2-MI.

Troponin Release and Reversible Left Ventricular Dysfunction After Transient Pressure Overload

BACKGROUND

The authors previously demonstrated that brief ischemia elicits cardiac troponin I (cTnI) release and myocyte apoptosis in the absence of necrosis. It remains uncertain whether other pathophysiological stresses can produce apoptosis and transient cTnI release without ischemia.

OBJECTIVES

This study sought to determine whether a transient increase in left ventricular (LV) preload elicits cTnI release in the absence of ischemia.

METHODS

Propofol-anesthetized swine (N = 13) received intravenous phenylephrine (PE) (300 μg/min) for 1 h to increase left ventricular end-diastolic pressure (LVEDP) to ∼30 mm Hg. Serial cTnI and echocardiographic function were assessed for 24 h, and myocardial tissue was analyzed for apoptosis and necrosis.

RESULTS

PE infusion increased systolic blood pressure from 137 ± 14 mm Hg to 192 ± 11 mm Hg (mean ± SD; p < 0.001) and increased LVEDP from 17 ± 2 mm Hg to 30 ± 5 mm Hg (p < 0.001). Myocardial flow measurements demonstrated no evidence of ischemia. Hemodynamics normalized rapidly after PE, but LV ejection fraction remained depressed (32 ± 21% vs. 58 ± 7%; p < 0.01) with normalization after 24 h (51 ± 16%; p = 0.31). Baseline transcoronary cTnI release was low (16 ± 20 ng/l) but increased to 856 ± 956 ng/l (p = 0.01) 1 h after LVEDP elevation. Circulating cTnI rose above the 99th percentile within 30 min and remained elevated at 24 h (1,462 ± 1,691 ng/l). Pathological analysis demonstrated myocyte apoptosis at 3 h (31.3 ± 11.9 myocytes/cm² vs. 4.6 ± 3.7 myocytes/cm²; p < 0.01), that normalized after 24 h (6.2 ± 5.6 myocytes/cm²; p = 0.46) without histological necrosis.

CONCLUSIONS

Transient elevations of LVEDP lead to cTnI release, apoptosis, and reversible stretch-induced stunning in the absence of ischemia. Thus, preload-induced myocyte injury may explain many cTnI elevations seen in the absence of clinical signs or symptoms of myocardial ischemia.

Cardiac Troponin I and Risk of Cardiac Events in Patients With Heart Failure and Preserved Ejection Fraction

BACKGROUND

Levels of cTn (cardiac troponin) are frequently elevated in patients with heart failure (HF) and reduced ejection fraction (EF) and correlate with the risk for mortality. However, factors associated with high cTn concentrations and the association with cardiovascular events in patients with HF and preserved EF are unclear.

METHODS AND RESULTS

Of 1767 subjects with symptomatic HF with preserved EF from the Americas part of the TOPCAT trial (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist Trial), 236 underwent baseline measurements of high-sensitivity (hs) cTnI using the Abbott Architect STAT assay. Baseline factors correlated with hs-cTnI levels were assessed in stepwise linear regression models and the association between hs-cTnI and adjudicated study outcomes was examined in Cox models. The median hs-cTnI concentration at baseline was 6.3 ng/L (interquartile range, 3.4-12.9 ng/L) with levels detectable in 99.2% of patients. Higher hs-cTnI concentrations were associated with male sex, black race, lower estimated glomerular filtration rate and higher NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels. After multivariable adjustment, higher concentrations of hs-cTnI were associated with greater risk for the composite of cardiovascular death or HF hospitalization (69 events during mean follow-up 2.6±1.5 years): hazard ratio 1.42 (95% CI, 1.20-1.69), P<0.001 per doubling of hs-cTnI. Compared with those in the lowest quartile of hs-cTnI, patients in the highest quartile demonstrated a nearly 5-fold higher risk of cardiovascular death and HF hospitalization (hazard ratio 4.85 [1.99-11.83], P=0.001). There was no interaction between hs-cTnI and spironolactone treatment with regard to the primary composite end point (interaction P=0.94).

CONCLUSIONS

In ambulatory patients with HF with preserved EF, levels of hs-cTnI are higher in male patients with black race, lower estimated glomerular filtration rate, and higher NT-proBNP. As in those with HF and reduced EF, higher hs-cTnI levels are independently associated with risk for cardiovascular death and HF hospitalization.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT00094302.

An Appraisal of Biomarker-Based Risk-Scoring Models in Chronic Heart Failure: Which One Is Best?

PURPOSE OF REVIEW

While prediction models incorporating biomarkers are used in heart failure, these have shown wide-ranging discrimination and calibration. This review will discuss externally validated biomarker-based risk models in chronic heart failure patients assessing their quality and relevance to clinical practice.

RECENT FINDINGS

Biomarkers may help in determining prognosis in chronic heart failure patients as they reflect early pathologic processes, even before symptoms or worsening disease. We present the characteristics and describe the performance of 10 externally validated prediction models including at least one biomarker among their predictive factors. Very few models report adequate discrimination and calibration. Some studies evaluated the additional predictive value of adding a biomarker to a model. However, these have not been routinely assessed in subsequent validation studies. New and existing prediction models should include biomarkers, which improve model performance. Ongoing research is needed to assess the performance of models in contemporary patients.

Biochemical and histological changes in the heart of post-partum rats exposed to Natron

Background

The customary puerperal practice of Natron consumption has been identified as one of the predisposing factors in the etiology of peripartum cardiomyopathy (PPCM). This study was designed to investigate the effect of Natron in postpartum Wistar albino rats.

Methods

A total of 30 postpartum Wistar rats were exposed to different doses (50 mg/kg, 100 mg/kg, 200 mg/kg and 300 mg/kg) of Natron for 28 days. After the treatment, we carried out biochemical analyses and histological evaluations of kidney, liver and heart.

Results

The study revealed that the exposure of postpartum rats to 100 mg/kg of Natron and above significantly (p < 0.05) increase the cardiac markers; myoglobin, creatine kinase-MB, troponin I and T as compared with control. The result of liver function indicated no significant difference in alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase, albumin and total protein of the Natron treated groups as compared with control. However, at higher doses, the levels of total protein, globulin and alkaline phosphatase activity were significantly increased in comparison to the control. There was no significant difference in the kidney function markers of the treatment groups as compared with control. Histological examinations revealed no changes in the kidney of the treated groups. Mild portal triaditis was observed in the liver of the treated rats. The heart of the rats administered ≥100 mg/kg of Natron showed myocyte hypertrophy.

Conclusion

The study demonstrated that the administration of Natron for 28 days caused changes in the heart of postpartum rats and thus may contribute to the pathogenesis of PPCM.

Cardiac troponins: from myocardial infarction to chronic disease

Elucidation of the physiologically distinct subunits of troponin in 1973 greatly facilitated our understanding of cardiac contraction. Although troponins are expressed in both skeletal and cardiac muscle, there are isoforms of troponin I/T expressed selectively in the heart. By exploiting cardiac-restricted epitopes within these proteins, one of the most successful diagnostic tests to date has been developed: cardiac troponin (cTn) assays. For the past decade, cTn has been regarded as the gold-standard marker for acute myocardial necrosis: the pathological hallmark of acute myocardial infarction (AMI). Whilst cTn is the cornerstone for ruling-out AMI in patients presenting with a suspected acute coronary syndrome (ACS), elevated cTn is frequently observed in those without clinical signs indicative of AMI, often reflecting myocardial injury of 'unknown origin'. cTn is commonly elevated in acute non-ACS conditions, as well as in chronic diseases. It is unclear why these elevations occur; yet they cannot be ignored as cTn levels in chronically unwell patients are directly correlated to prognosis. Paradoxically, improvements in assay sensitivity have meant more differential diagnoses have to be considered due to decreased specificity, since cTn is now more easily detected in these non-ACS conditions. It is important to be aware cTn is highly specific for myocardial injury, which could be attributable to a myriad of underlying causes, emphasizing the notion that cTn is an organ-specific, not disease-specific biomarker. Furthermore, the ability to detect increased cTn using high-sensitivity assays following extreme exercise is disconcerting. It has been suggested troponin release can occur without cardiomyocyte necrosis, contradicting conventional dogma, emphasizing a need to understand the mechanisms of such release. This review discusses basic troponin biology, the physiology behind its detection in serum, its use in the diagnosis of AMI, and some key concepts and experimental evidence as to why cTn can be elevated in chronic diseases.

Proteostasis in cardiac health and disease

The incidence and prevalence of cardiac diseases, which are the main cause of death worldwide, are likely to increase because of population ageing. Prevailing theories about the mechanisms of ageing feature the gradual derailment of cellular protein homeostasis (proteostasis) and loss of protein quality control as central factors. In the heart, loss of protein patency, owing to flaws in genetically-determined design or because of environmentally-induced 'wear and tear', can overwhelm protein quality control, thereby triggering derailment of proteostasis and contributing to cardiac ageing. Failure of protein quality control involves impairment of chaperones, ubiquitin-proteosomal systems, autophagy, and loss of sarcomeric and cytoskeletal proteins, all of which relate to induction of cardiomyocyte senescence. Targeting protein quality control to maintain cardiac proteostasis offers a novel therapeutic strategy to promote cardiac health and combat cardiac disease. Currently marketed drugs are available to explore this concept in the clinical setting.

Minute Myocardial Injury as Measured by High-Sensitive Troponin T Serum Levels Predicts the Response to Intracoronary Infusion of Bone Marrow-Derived Mononuclear Cells in Patients With Stable Chronic Post-Infarction Heart Failure: Insights From the TOPCARE-CHD Registry

RATIONALE

Cell-based therapies are a promising option in patients with chronic postinfarction heart failure (ischemic cardiomyopathy [ICM]). However, the responses after intracoronary infusion of autologous bone marrow-derived mononuclear cells (BMCs) are heterogeneous, which may be related to impaired cell retention in patients with ICM. Ischemic injury is associated with upregulation of prototypical chemoattractant cytokines mediating retention and homing of circulating cells. The development of ultrasensitive tests to measure high-sensitive troponin T (hs-TnT) serum levels revealed the presence of ongoing minute myocardial injury even in patients with stable ICM.

OBJECTIVE

To test the hypothesis that serum levels of hs-TnT correlate with cell retention and determine the response to intracoronary BMC application in patients with ICM.

METHODS AND RESULTS

About 157 patients with stable ICM and no substantial impairment of kidney function received intracoronary BMC administration. Immediately prior to cell application, hs-TnT levels to measure myocardial injury and NT-proBNP levels as marker of left ventricular wall stress were determined. Patients with elevated hs-TnT were older and had more severe heart failure. Importantly, only patients with elevated baseline hs-TnT≥15.19 pg/mL (upper tertile) demonstrated a significant (P=0.04) reduction in NT-proBNP serum levels (-250 [-1465; 33] pg/mL; relative reduction -24%) 4 months after BMC administration, whereas NT-proBNP levels remained unchanged in patients in the 2 lower hs-TnT tertiles. The absolute decrease in NT-proBNP at 4 months was inversely correlated with baseline hs-TnT (r=-0.27, P=0.001). Finally, retention of intracoronarily infused, ¹¹¹Indium-labeled cells within the heart was closely associated with hs-TnT levels in patients with chronic ischemic heart failure (P=0.0008, n=10, triple measurements).

CONCLUSIONS

The extent of ongoing myocardial injury as measured by serum levels of hs-TnT predicts the reduction of NT-proBNP serum levels at 4 months after intracoronary BMC administration in patients with ICM, suggesting that the beneficial effects of BMC application on LV remodeling and wall stress are confined to patients with ongoing minute myocardial injury.

CLINICAL TRIAL REGISTRATION

URL: www.clinicaltrials.gov. Unique identifier: NCT00962364.

Cardiac biomarkers of acute coronary syndrome: from history to high-sensitivity cardiac troponin

The role of cardiac troponins as diagnostic biomarkers of myocardial injury in the context of acute coronary syndrome (ACS) is well established. Since the initial 1st-generation assays, 5th-generation high-sensitivity cardiac troponin (hs-cTn) assays have been developed, and are now widely used. However, its clinical adoption preceded guidelines and even best practice evidence. This review summarizes the history of cardiac biomarkers with particular emphasis on hs-cTn. We aim to provide insights into using hs-cTn as a quantitative marker of cardiomyocyte injury to help in the differential diagnosis of coronary versus non-coronary cardiac diseases. We also review the recent evidence and guidelines of using hs-cTn in suspected ACS.

Subclinical elevation of high-sensitive troponin T levels at the convalescent stage is associated with increased 5-year mortality after ST-elevation myocardial infarction

BACKGROUND

It is unclear whether serum high-sensitive troponin T (hs-TnT) levels at the convalescent stage of ST-elevation myocardial infarction (STEMI) are associated with long-term mortality.

METHODS

This study enrolled a total of 2944 consecutive STEMI patients who were registered in the Osaka Acute Coronary Insufficiency Study between 2000 and 2009, and whose hs-TnT levels were evaluated at the convalescent stage. Patients were divided into four hs-TnT category groups according to the results of survival classification and regression tree (CART) analysis. The impact of hs-TnT levels on 5-year mortality was evaluated using multivariate Cox regression analysis.

RESULTS

Only one patient had hs-TnT level below the detection limit of the assay (<0.003ng/mL). The median hs-TnT level was 0.025 (quartile 0.011-0.083)ng/mL. During the median follow-up period of 1782 days, 188 patients died. Survival CART analysis revealed that the 1st, 2nd, and 3rd discriminating hs-TnT levels to discern 5-year mortality were 0.028, 0.008, and 1.340ng/mL, respectively. The adjusted hazard ratios for the medium-low (0.009-0.028ng/mL), medium-high (0.029-1.340ng/mL), and high-risk (≥1.341ng/mL) groups were 3.03 (95% confidence interval 1.18-7.77, p=0.021), 4.29 (1.63-11.28, p=0.003), and 8.68 (2.20-34.27, p=0.002), respectively. Integrated discrimination improvement (IDI) analysis revealed that incorporation of this hs-TnT classification scheme with other clinical variables statistically improved the discriminatory accuracy for 5-year mortality, with a time-dependent IDI of 0.0076 (p=0.033).

CONCLUSIONS

hs-TnT levels at the convalescent stage were associated with long-term mortality in STEMI patients. Even subclinical elevation of hs-TnT levels was associated with increased 5-year mortality.

Diagnosis and management of type II myocardial infarction: increased demand for a limited supply of evidence

Type 2 myocardial infarction (type 2 MI) is defined as myocardial necrosis that results from an imbalance of myocardial oxygen supply and demand. Although type 2 MI is highly prevalent and strongly associated with mortality, the pathophysiology remains poorly understood. Discrepancies in definitions, frequency of screening, diagnostic approaches, and methods of adjudication lead to confusion and misclassification. To date, there is no consensus on the diagnostic criteria for type 2 MI. No guidelines exist for the optimal management of this condition, and further investigation is urgently needed. This review explores the existing evidence on the pathophysiology, diagnosis, prognosis, and management of type 2 MI.

Which biomarkers do clinicians need for diagnosis and management of heart failure with reduced ejection fraction?

While there have been significant recent advances in the medical management of chronic HF (including the use of beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and aldosterone blockers), the ability to characterize, monitor, and predict a patient's response to HF therapy is poor. Risk stratification is important in patients with chronic heart failure and enables informed decisions about treatment and end-of-life care. Clinical parameters, such as advanced age, higher NYHA functional class, reduced left ventricular ejection fraction, lower body mass index, renal dysfunction, and anemia have all been associated with poor outcomes in HF. More recently, heart failure biomarkers have considerably changed the way we take care of our HF patients. BNP and NT-proBNP are endorsed by current guidelines and are now the gold standard biomarkers to confirm the diagnosis and to evaluate the prognosis of heart failure. Studies on natriuretic peptide-guided HF therapy look promising. Novel biomarkers, such soluble ST2, growth differentiation factor-15, highly sensitive troponins and Galectin-3, show potential in assessing prognosis beyond the established natriuretic peptides, but their role in the clinical care of the patient is still partially defined and more studies are needed.

Prognostic significance of a multimarker strategy of biomarkers in acute heart failure

BACKGROUND

Heart failure (HF) is a growing public health problem. Patients often present to emergency department (ED) with acute onset dyspnea where a rapid triage is required to avoid misdiagnosis and to institute appropriate therapy. An objective risk-stratification in the ED is warranted to identify patients at high risk of adverse outcomes, so that more intensive therapy and vigilant follow-up after discharge are instituted.

METHODS AND RESULTS

Fifty two consecutive acute HF (AHF) patients in NYHA class III/IV were enrolled for the present study. N-terminal pro B-type natriuretic peptide (NT-proBNP), high-sensitivity cardiac troponin T (hsTropT), high-sensitivity C-reactive protein (hsCRP) and Uric acid (UA) were evaluated at admission; a second sample for NT-proBNP and hsTropT was obtained 48h later. The end-point of the study, a composite of cardiovascular death, rehospitalisation for worsening HF symptoms and refractory HF was reached in 32.7% of patients during a median follow-up of 4.8mnth. Although, hsTropT (>0.014ng/ml), hsCRP (>0.5mg/dl) and UA (>5.6mg/dl for females and >7 mg/dl for males) were elevated in the vast majority of patients (92.3%, 75% and 63.5% respectively), baseline and changing patterns of NT-proBNP following treatment were the only predictors of adverse outcomes on follow-up. A significant correlation between hsTropT, hsCRP and UA was observed suggesting a link between inflammation, myocyte injury and oxidative stress in AHF.

CONCLUSION

Baseline and changing patterns of NT-proBNP predicted adverse outcomes on follow-up suggesting that a strategy of serial measurement of NT-proBNP could prove invaluable in early risk stratification. Further research is needed to understand the link between inflammation, myocyte injury and oxidative stress in AHF which could provide potential therapeutic targets.

Old and newer biomarkers in heart failure: from pathophysiology to clinical significance

Heart failure is a complex disease in which a careful clinical examination and the measurement of cardiac function may not always be sufficient for making a correct diagnosis. Measuring plasma levels of natriuretic peptides may assist in this process, also offering a good tool for accurate risk stratification. Other alternative biomarkers may give insight into the different pathways of heart failure genesis and pathophysiology, and may help to identify those patients with overt heart failure and a more adverse outcome, or distinguish between those at risk of developing heart failure. Despite a high number of potentially useful biomarkers, only a few will likely be introduced routinely into clinical practice. However, a multi-marker approach might increase the diagnostic accuracy and it might identify different phenotypes of heart failure patients who might benefit from individualized therapy in the future.

Cardiac and proinflammatory markers predict prognosis in cirrhosis

BACKGROUND & AIMS

Inflammation and cardiac dysfunction plays an important role in the development of complications leading to increased mortality in patients with cirrhosis. Novel cardiac markers such as prohormone of ANP (proANP), copeptin and high-sensitivity troponin T (hs-TnT) and proinflammatory markers including soluble urokinase-type plasminogen activator receptor (suPAR) and high-sensitive C-reactive protein (hs-CRP) are related to these complications. We aimed to investigate if cardiac and proinflammatory markers are related to severity of liver disease, cardiac and haemodynamic changes, and long-term survival.

METHODS

One hundred and ninety-three stable cirrhotic patients (Child class: A = 46; B = 97; C = 50) had a full haemodynamic investigation performed with measurement of splanchnic and systemic haemodynamics and measurement of circulating levels of proBNP, proANP, copeptin, hs-TnT, LBP, IL 6, IL 8, IP 10, VEGF, hs-CRP and suPAR.

RESULTS

Soluble urokinase-type plasminogen activator receptor soluble urokinase-type plasminogen activator receptor, hs-CRP, and hs-TnT were significantly different throughout the Child classes (P < 0.01; P < 0.01; P < 0.02). All markers except copeptin correlated with indicators of disease severity in cirrhosis; ProANP and suPAR correlated with hepatic venous pressure gradient (r = 0.24 and r = 0.34; P < 0.001) and systemic vascular resistance (r = -0.24 and r = -0.33; P < 0.001). Cardiac (proANP, hs-TnT; P < 0.01) and proinflammatory (hs-CRP, suPAR; P < 0.05) markers were associated with mortality in a univariate Cox analysis, however, the strongest predictors of mortality in a multivariate Cox analysis were hs-TnT, ascites and hepatic venous pressure gradient (reg.coeff.: 0.34, P < 0.001; 0.16, P < 0.001; 0.06, P = 0.04).

CONCLUSION

Markers of cardiac dysfunction and inflammation are significantly associated with disease severity, degree of portal hypertension and survival in cirrhosis. In particular, hs-TnT and suPAR seem to contain prognostic information.

Cationic isotachophoresis separation of the biomarker cardiac troponin I from a high-abundance contaminant, serum albumin

Cationic ITP was used to separate and concentrate fluorescently tagged cardiac troponin I (cTnI) from two proteins with similar isoelectric properties in a PMMA straight-channel microfluidic chip. In an initial set of experiments, cTnI was effectively separated from R-Phycoerythrin using cationic ITP in a pH 8 buffer system. Then, a second set of experiments was conducted in which cTnI was separated from a serum contaminant, albumin. Each experiment took ∼10 min or less at low electric field strengths (34 V/cm) and demonstrated that cationic ITP could be used as an on-chip removal technique to isolate cTnI from albumin. In addition to the experimental work, a 1D numerical simulation of our cationic ITP experiments has been included to qualitatively validate experimental observations.

Inflammation and disease activity are associated with high circulating cardiac markers in rheumatoid arthritis independently of traditional cardiovascular risk factors

OBJECTIVE

To measure concentrations of high-sensitivity cardiac troponin (HS-cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients with rheumatoid arthritis (RA) and to examine correlates.

METHODS

The plasma concentrations of HS-cTnT and NT-proBNP were measured in consecutive patients with RA and compared to values obtained from age-matched and sex-matched healthy controls.

RESULTS

We included 236 unrelated patients with RA (192 females, 57 ± 13 yrs) and 213 controls (170 females, 55 ± 15 yrs). Seventy-one patients with RA were free of cardiovascular (CV) risk factors. HS-cTnT and NT-proBNP concentrations were significantly higher in the total cohort of patients with RA (p = 0.03 and p < 0.0001, respectively) and in the subgroup free of CV risk factors (p = 0.02 and p < 0.0001, respectively) compared to controls. In addition, both the total cohort of patients with RA and the subgroup free of CV risk factors were more likely to have levels above the cutoff concentrations of HS-cTnT (p = 0.003 and p = 0.007, respectively) and NT-proBNP (p = 0.0001 and p < 0.0001, respectively) than controls. Patients with RA and increased C-reactive protein (CRP) levels had higher HS-cTnT (p = 0.03) and NT-proBNP (p = 0.02) concentrations. HS-cTnT levels positively correlated with the 28-joint Disease Activity Score (DAS28-CRP; r = 0.2, p = 0.020). Multivariate logistic regression analysis indicated that increased HS-cTnT levels were independently associated with a DAS28-CRP > 5.1 (OR 11.8; 95% CI 1.6-35.5) and a body mass index > 30 kg/m(2) (OR 2.7; 95% CI 1.3-5.5).

CONCLUSION

HS-cTnT and NTproBNP are increased in patients with RA, independent of CV risk factors. The association between HS-cTnT, NT-proBNP, and CRP, together with the correlation between HS-cTnT and disease activity, support the link between myocardial injury/dysfunction and inflammation.

Troponin I, but not BNP, is associated with phosphorus, calcium and vitamin D in stable coronary artery disease

BACKGROUND

Elevated plasma cardiac troponin, elevated plasma phosphorus and decreased plasma vitamin D have been shown to be associated with negative outcomes.

METHODS AND RESULTS

Troponin I, calcium, phosphorus and 25-OH vitamin D were studied in a cohort of 60 patients with stable coronary heart disease and preserved left ventricular function. Using a cut-off value of 0.012 ng/mL for plasma troponin I, patients with higher values (18 patients), when compared to the other patients (n=42), had higher mean values for plasma phosphorus (3.42+0.45 mg/dL vs 3.17+0.45 mg/dL, p= 0.041) and calcium (5.08+0.23 mEq/L vs 4.92+0.18 mEq/L, p= 0.016) and lower values for 25-OH vitamin D (14.2+5.6 ng/mL vs 19.4+8.8 ng/mL, p= 0.032). Binary logistic regression analysis showed that troponin I > 0.012 ng/ml is associated with increased phosphorus, increased calcium and decreased 25-OH vitamin D concentrations. A similar analysis using BNP >100 pg/mL failed to show signifcant associations with phosphorus, calcium and 25-OH vitamin D concentrations.

CONCLUSIONS

In patients with stable coronary artery disease and preserved left ventricular function, those having cardiac troponin I > 0.012 ng/ml, but not those having BNP >100 pg/mL, had higher plasma phosphorus, higher plasma calcium and lower plasma 25-OH vitamin D concentrations than those having cardiac troponin I ≤ 0.012 ng/ml (or BNP ≤ 100 pg/mL).

Heart failure with preserved or reduced ejection fraction in patients treated with peritoneal dialysis

BACKGROUND

Heart failure is one of the most frequent complications in dialysis patients. However, little is known of the significance of the entity "heart failure with preserved ejection fraction" (HFPEF) in this population. This study aimed to determine the prevalence, clinical profiles, and long-term outcomes of peritoneal dialysis patients with HFPEF.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

220 patients treated with peritoneal dialysis were recruited from a university teaching hospital in Hong Kong.

PREDICTOR

Heart failure was defined clinically based on the presence of: (1) symptoms and signs, including dyspnea, increased jugular venous pressure, and basal crepitations; (2) radiographic evidence of pulmonary venous congestion or interstitial edema; and (3) resolution of symptoms, signs, and radiographic changes with hypertonic peritoneal dialysis exchanges. Based on a combination of clinical history of heart failure and echocardiography-derived ejection fraction, patients were classified as having no heart failure, HFPEF, and heart failure with reduced ejection fraction (HFREF).

OUTCOMES

All-cause mortality, cardiac death, heart failure, and fatal or nonfatal cardiovascular events.

MEASUREMENTS

All patients underwent 2-dimensional echocardiography and tissue Doppler imaging at baseline and were followed up prospectively for clinical events for 4 years.

RESULTS

86 (39%) patients had heart failure, of whom 54.7% had preserved ejection fraction ≥50% and 45.3% had reduced ejection fraction <50%. Patients with HFPEF were intermediate between those with no heart failure and those with HFREF in terms of blood pressure, prevalence of coronary artery disease, diabetes, cardiac biomarkers, left ventricular mass, volume, and ratio of early mitral inflow velocity to peak mitral annulus velocity. In the multivariable Cox regression analysis, patients with HFPEF showed an increased adjusted HR for cardiac death (2.57; 95% CI, 1.20-5.50), heart failure (HR, 2.25; 95% CI, 1.28-3.96), and fatal or nonfatal cardiovascular event (HR, 2.01; 95% CI, 1.26-3.21) compared with those with no heart failure, but the risk was lower compared with those with HFREF.

LIMITATIONS

The study included prevalent peritoneal dialysis patients and may introduce survival bias.

CONCLUSIONS

HFPEF is common in peritoneal dialysis patients (∼55% of all heart failure) and is associated with increased risk of mortality and adverse cardiovascular outcomes compared with those with no heart failure, although the risk was lower than in patients with HFREF. This entity needs to be more recognized in peritoneal dialysis patients.

Do induced tachycardias within the scope of electrophysiological studies lead to elevated plasma troponin I levels?

AIMS

Troponin I (TNI) is an established marker for the diagnosis of acute coronary syndrome (ACS). The study evaluated if (induced) tachycardiac arrhyhthmias within the scope of the electrophysiological studies (EPS) led to elevation of TNI serum levels.

METHOD

TNI was measured in the serum of 28 patients before and after the EPS. The left ventricular ejection fraction (LV-EF) was investigated by two-dimensional echocardiography. Left ventricle hypertrophy (LVH) was measured according to the recommendations of the American Society of Echocardiography. All patients underwent coronary angiography prior to the EPS, and significant coronary heart disease was defined as stenosis > 50%. The EPS revealed supraventricular and ventricular tachycardias using the 18-step protocol with one, two, and three extrastimuli.

RESULTS

Indications for the EPS were syncope (n = 15), atrioventricular tachycardia (n = 4), non-sustained VT (n = 6), and sustained VT (n = 3). Coronary heart disease (CHD) was detected in 8 patients (1-vessel: n = 3; 2-vessel: n = 4; 3-vessel: n = 1), and 2 patients underwent percutaneous coronary intervention before EPS. Echocardiography revealed normal LV-EF in 18 patients and a reduction in the others (low n = 3, middle n = 5, high n = 2). Thirteen patients suffered from LVH. In 2 patients, external cardioversion was required during the EPS. TNI was elevated over 0.1 ng/ml (risk stratification cut-off for ACS) in 4 patients before and in 12 patients after EPS. There was no relationship between LV-EF, CHD, and the elevation of TNI after the EPS.

CONCLUSION

TNI can be elevated by (induced) tachycardias within the scope of electrophysiological studies without a relationship to LV-EF, LVH, and CHD.

A review of causes and systemic approach to cardiac troponin elevation

The first American College of Cardiology/European Society of Cardiology task force published recommendations for a universal definition of myocardial infarction (MI) in 2000 based on the measurement of troponin (Tn). Although this rapid and highly sensitive blood test is certainly valuable in the appropriate setting, its widespread use in variety of clinical scenarios may lead to the detection of Tn elevation in absence of thrombotic acute coronary syndrome. In 2007, the joint European Society of Cardiology/American College of Cardiology Foundation/American Heart Association/World Heart Federation task force proposed a new definition for acute MI based on detection of Tn and associated clinical evidence. The goal of this article is to review the universal definition of acute MI and to differentiate type 1 MI, type 2 MI, and non-acute coronary syndrome Tn elevations. The prognosis and a clinical approach to this differential diagnosis will be developed.