Systolic Blood Pressure, Diastolic Blood Pressure and Pulse Pressure and the Risk of Subclinical Myocardial Injury: The HUNT Study

BACKGROUND

Subclinical myocardial injury expressed as higher cardiac troponin concentrations may represent an important intermediary between hypertension and the risk of cardiovascular disease. The study aimed to assess the relative strength of associations between systolic blood pressure (BP), diastolic BP, and pulse pressure, and subclinical myocardial injury, and how change in BP variables over time associates with subclinical myocardial injury.

METHODS AND RESULTS

cTnl (cardiac troponin I) was measured in 32 968 participants of the fourth wave of the population-based cohort HUNT4 (Trøndelag Health Study) without a history of cardiovascular disease. An additional longitudinal analysis included participants from HUNT4 with BP measurements from HUNT3 (n=18 681). Associations between BP variables and cTnI concentrations were assessed by linear and logistic regression analyses. The median cTnI concentration was 1.6 ng/L (25th-75th percentiles, 0.6-3.1 ng/L), median age was 52 years (39.1-65.6 years), and 57% were female subjects. Cross-sectionally, only systolic BP categories ≥130 mm Hg associated with higher cTnI concentrations, compared with a reference systolic BP of <110 mm Hg. All categories of diastolic BP and pulse pressure were positively associated with higher cTnI concentrations when diastolic BP 70 to 79 mm Hg and pulse pressure <40 mm Hg were used as references, respectively. When comparing systolic BP, diastolic BP, and pulse pressure as continuous variables, cross-sectionally, pulse pressure most strongly associated with cTnI concentrations (P for all comparisons <0.001), whereas longitudinally, change in diastolic BP was most strongly associated with cTnI concentrations (P for all comparisons <0.05).

CONCLUSIONS

Subjects with high pulse pressure and longitudinal increase in diastolic BP are at higher risk for subclinical myocardial injury.

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.

Diagnostic and prognostic value of cardiac troponins in emergency department patients presenting after a fall: A prospective, multicenter study

BACKGROUND

Emergency department (ED) presentations after a ground-level fall (GLF) are common. Falls were suggested to be another possible presenting feature of a myocardial infarction (MI), as unrecognized MIs are common in older adults. Elevated high-sensitivity cardiac troponin (hs-cTn) concentrations could help determine the etiology of a GLF in ED. We investigated the prevalence of both MI and elevated high-sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI), as well as the diagnostic accuracy of hs-cTnT and hs-cTnI regarding MI, and their prognostic value in older ED patients presenting after a GLF.

METHODS

This was a prospective, international, multicenter, cohort study with a follow-up of up to 1 year. Patients aged 65 years or older presenting to the ED after a GLF were prospectively enrolled. Two outcome assessors independently reviewed all discharge records to ascertain final gold standard diagnoses. Hs-cTnT and hs-cTnI levels were determined from thawed samples for every patient.

RESULTS

In total, 558 patients were included. Median (IQR) age was 83 (77-89) years, and 67.7% were female. Elevated hs-cTnT levels were found in 384 (68.8%) patients, and elevated hs-cTnI levels in 86 (15.4%) patients. Three patients (0.5%) were ascertained the gold standard diagnosis MI. Within 30 days, 18 (3.2%) patients had died. Nonsurvivors had higher hs-cTnT and hs-cTnI levels compared with survivors (hs-cTnT 40 [23-85] ng/L in nonsurvivors and 20 [13-33] ng/L in survivors; hs-cTnI 25 [14-54] ng/L in nonsurvivors and 8 [4-16] ng/L in survivors; p < 0.001 for both).

CONCLUSIONS

A majority of patients (n = 364, 68.8%) presenting to the ED after a fall had elevated hs-cTnT levels and 86 (15.4%) elevated hs-cTnI levels. However, the incidence of MI in these patients was low (n = 3, 0.5%). Our data do not support the opinion that falls may be a common presenting feature of MI. We discourage routine troponin testing in this population. However, hs-cTnT and hs-cTnI were both found to have prognostic properties for mortality prediction up to 1 year.

High-Sensitivity Cardiac Troponin T and Cognitive Function Over 12 Months After Stroke-Results of the DEMDAS Study

BACKGROUND

Subclinical myocardial injury in form of hs-cTn (high-sensitivity cardiac troponin)  levels has been associated with cognitive impairment and imaging markers of cerebral small vessel disease (SVD) in population-based and cardiovascular cohorts. Whether hs-cTn is associated with domain-specific cognitive decline and SVD burden in patients with stroke remains unknown.

METHODS AND RESULTS

We analyzed patients with acute stroke without premorbid dementia from the prospective multicenter DEMDAS (DZNE [German Center for Neurodegenerative Disease]-Mechanisms of Dementia after Stroke) study. Patients underwent neuropsychological testing 6 and 12 months after the index event. Test results were classified into 5 cognitive domains (language, memory, executive function, attention, and visuospatial function). SVD markers (lacunes, cerebral microbleeds, white matter hyperintensities, and enlarged perivascular spaces) were assessed on cranial magnetic resonance imaging to constitute a global SVD score. We examined the association between hs-cTnT (hs-cTn T levels) and cognitive domains as well as the global SVD score and individual SVD markers, respectively. Measurement of cognitive and SVD-marker analyses were performed in 385 and 466 patients with available hs-cTnT levels, respectively. In analyses adjusted for demographic characteristics, cardiovascular risk factors, and cognitive status at baseline, higher hs-cTnT was negatively associated with the cognitive domains "attention" up to 12 months of follow-up (beta-coefficient, -0.273 [95% CI, -0.436 to -0.109]) and "executive function" after 12 months. Higher hs-cTnT was associated with the global SVD score (adjusted odds ratio, 1.95 [95% CI, 1.27-3.00]) and the white matter hyperintensities and lacune subscores.

CONCLUSIONS

In patients with stroke, hs-cTnT is associated with a higher burden of SVD markers and cognitive function in domains linked to vascular cognitive impairment.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01334749.

Synthesis and Biophysical Characterization of Fingolimod Derivatives as Cardiac Troponin Antagonists

Calcium binding to cardiac troponin C (cTnC) in the thin filaments acts as a trigger for cardiac muscle contraction. The N-lobe of cTnC (NcTnC) undergoes a conformational change in the presence of calcium that allows for interaction with the switch region of cardiac troponin I (cTnISP), releasing its inhibitory effect on the thin filament structure. The small molecule fingolimod inhibits cTnC-cTnISP interactions via electrostatic repulsion between its positively charged tail and positively charged residues in cTnISP and acts as a calcium desensitizer of the contractile myofilaments. Here we investigate the structure-activity relationship of the fingolimod hydrophobic headgroup and show that increasing the alkyl chain length increases both its affinity for NcTnC and its inhibitory effect on the NcTnC-cTnISP interaction and that decreasing flexibility completely abolishes these effects. Strikingly, the longer derivatives have no effect on the calcium affinity of cTnC, suggesting that they act as better inhibitors.

Sex Differences in Outcomes of Acute Myocardial Injury After Stroke

BACKGROUND

Sex differences in presentation, treatment, and prognosis of cardiovascular disorders are well recognized. Although an association between acute myocardial injury and mortality after ischemic stroke has been demonstrated, it is unclear whether prevalence and outcome of poststroke acute myocardial injury differ between women and men.

METHODS AND RESULTS

We prospectively screened consecutive patients with acute ischemic stroke and serial high-sensitivity cardiac troponin T measurements admitted to our center. Acute myocardial injury was defined as at least 1 high-sensitivity cardiac troponin T value above the upper reference limit (14 ng/L) with a rise/fall of >20%. Rates of acute myocardial injury were also calculated using sex-specific high-sensitivity cardiac troponin T cutoffs (women upper reference limit, 9 ng/L; men upper reference limit, 16 ng/L). Logistic regression analyses were performed to evaluate the association between acute myocardial injury and outcomes. Of 1067 patients included, 494 were women (46%). Women were older, had a higher rate of known atrial fibrillation, were more likely to be functionally dependent before admission, had higher stroke severity, and more often had cardioembolic strokes (all P values <0.05). The crude prevalence of acute myocardial injury differed by sex (29% women versus 23% men, P=0.024). Statistically significant associations between acute myocardial injury and outcomes were observed in women (7-day in-hospital mortality: adjusted odds ratio [aOR], 3.2 [95% CI, 1.07-9.3]; in-hospital mortality: aOR, 3.3 [95% CI, 1.4-7.6]; modified Rankin Scale score at discharge: aOR, 1.6 [95% CI, 1.1-2.4]) but not in men. The implementation of sex-specific cutoffs did not increase the prognostic value of acute myocardial injury for unfavorable outcomes.

CONCLUSIONS

The prevalence of acute myocardial injury after ischemic stroke and its association with mortality and greater disability might be sex-dependent.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03892226.

NT-proBNP/cardiac troponin T ratio >7.5 on the second day of admission can differentiate Takotsubo from acute coronary syndrome with good accuracy

BACKGROUND

Takotsubo syndrome (TTS) is not usually diagnosed until patients with suspected acute coronary syndrome (ACS) and echocardiographically detected apical aneurysm are found to have "normal" coronary angiography (CA). Our aim was to explore whether cardiac biomarkers can contribute to the early diagnosis of TTS.

METHODS

Ratios of N-terminal-pro brain natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (cTnT) both expressed in pg/mL [admission and the 3 following days] were compared in 38 patients with TTS and 114 ACS patients of whom 58 had non-ST-elevation myocardial infarction (NSTEMI).

RESULTS

NT-proBNP/cTnT ratio at admission and during the following 3 days was significantly higher in TTS compared to patients with ACS [18.4 (8.7-41.7) vs 2.9 (0.8-6.8), 29.6 (14.3-53.7) vs 1.2 (0.5-2.7), 30.0 (11.6-50.9) vs 1.7 (0.5-3.0), 27.8 (11.3-42.6) vs 1.4 (0.6-2.8), respectively, all <0.001]. Βest discrimination of TTS from ACS was possible with the ratio of NT-proBNP/cTnT on the 2nd day. A cut-off value of NT-proBNP/cTnT ratio >7.5 had a sensitivity of 97.3%, a specificity of 95.4% and an accuracy of ∼96% in detecting TTS as opposed to ACS. Furthermore, the ratio of NT-proBNP/cTnT preserved its discriminatory value in the subgroup of patients with NSTEMI. In particular, an NT-proBNP/cTnT ratio >7.5 on the 2nd day had a sensitivity of 97.3%, a specificity of 91.4%, and an accuracy of 93.7% in differentiating TTS from NSTEMI.

CONCLUSIONS

An NT-proBNP/cTnT ratio >7.5 on the 2nd day of admission can be useful for the early identification of TTS among selected patients initially presenting with ACS, a ratio more clinically useful in the setting of NSTEMI.

Rising Cardiac Troponin: A Prognostic Biomarker for Mortality After Acute Ischemic Stroke

BACKGROUND

Elevated cardiac troponin (cTn) is detected in 10% to 30% of patients with acute ischemic stroke (AIS) and correlates with poor functional outcomes. Serial cTn measurements differentiate a dynamic cTn pattern (rise/fall >20%), specific for acute myocardial injury, from elevated but stable cTn levels (nondynamic), typically attributed to chronic cardiac/noncardiac conditions. We investigated if the direction of the cTn change (rising versus falling) affects mortality and outcome.

METHODS AND RESULTS

We retrospectively screened consecutive patients with AIS admitted to 5 stroke centers for elevated cTn at admission and at least 1 additional cTn measurement within 48 hours. The pattern of cTn was defined as rising if >20% increase from baseline, falling if >20% decrease, or nondynamic if ≤20% change in either direction. Logistic regression analyses were performed to assess the association of cTn patterns and 7-day mortality and unfavorable discharge disposition. Of 3789 patients with AIS screened, 300 were included. Seventy-two had a rising pattern, 66 falling, and 162 nondynamic. In patients with AIS with rising cTn, acute ischemic myocardial infarction was present in 54%, compared with 33% in those with falling cTn (P<0.01). Twenty-two percent of patients with a rising pattern had an isolated dynamic cTn in the absence of any ECG or echocardiogram changes, compared with 53% with falling cTn. A rising pattern was associated with higher risk of 7-day mortality (adjusted odds ratio [OR]=32 [95% CI, 2.5-415.0] rising versus aOR=1.3 [95% CI, 0.1-38.0] falling versus nondynamic as reference) and unfavorable discharge disposition (aOR=2.5 [95% CI, 1.2-5.2] rising versus aOR=0.6 [95% CI, 0.2-1.5] versus falling).

CONCLUSIONS

Rising cTn is independently associated with increased mortality and unfavorable discharge disposition in patients with AIS.

Global research trends on cardiac troponin and physical activity among pediatric populations: a bibliometric analysis and science mapping study

Background

Cardiac troponin (cTn) is a reliable marker for evaluating myocardial damage. cTn is a very specific protein involved in myocardial injury, and it is a key factor in the diagnosis of coronary syndromes. Bibliometric analysis was applied in the present work, with the main goal of evaluating global research on the topic of cardiac troponin in pediatric populations.

Methods

Publications about cardiac troponin and physical activity in pediatric populations were retrieved from the Social Sciences Citation Index (SSCI) and the Science Citation Index Expanded (SCIE) of the Web of Science Core Collection, and they were then analyzed. The study was able to identify the key bibliometric indicators, such as publications, keywords, authors, countries, institutions, and journals. For the analysis, VOSviewer, R-based Bibliometrix (4.2.2), and MapChart were used.

Results

Initially, 98 documents were identified; however, once inclusion and exclusion criteria were applied, the number of documents decreased to 88. The search yielded 79 original research articles and 9 reviews, almost all of which were published in the past 2 decades. The total number of citations (Nc) of the retrieved publications was 1,468, and the average number of citations per article (Na) was 16.68. In general, 508 authors were found to have participated in research about troponin; they were associated with 256 institutions, and their work was published in 65 different journals from around the world. The authors hailed from 30 countries and/or regions. The year 2022 was the most productive year for the publication of the selected documents. The bibliometric analysis provided information regarding levels of cooperation among authors and institutions. In fact, China, the United States, and England were the most productive nations, and the journal with the greatest number of publications on the topic was Pediatric Cardiology.

Summary

The number of publications and the trend line show that research on this topic has not yet reached a stage of maturity. There are referent investigators, countries, and institutions that have laid the foundations for subsequent studies on the analyzed topic.

Novel Biomarkers in Early Detection of Heart Failure: A Narrative Review

Heart failure (HF) represents a significant global health challenge, characterized by a variety of symptoms resulting from cardiac dysfunction. This dysfunction often leads to systemic and pulmonary congestion. The pathophysiology of HF is complex, involving stimulation of the sympathetic nervous system, which is insufficiently balanced by the release of natriuretic peptide. This imbalance leads to progressive hypertrophy and dilatation of the heart's chambers, impairing its pumping efficiency and increasing the risk of arrhythmias and conduction disorders. The prevalence of HF is exceptionally high in industrialized nations and is expected to increase owing to an aging population and advancements in diagnostic methods. This study emphasizes the critical role of early diagnosis in reducing morbidity and mortality associated with HF, focusing specifically on the evolving importance of biomarkers in managing this condition. Biomarkers have played a key role in transforming the diagnosis and treatment of HF. Traditional biomarkers such as b-type natriuretic peptide and N-terminal pro-b-type natriuretic peptide have been widely adopted for their cost-effectiveness and ease of access. However, the rise of novel biomarkers such as growth differentiation factor 15 and adrenomedullin has shown promising results, offering superior sensitivity and specificity. These new biomarkers enhance diagnostic accuracy, risk stratification, and prognostic evaluation in HF patients. Despite these advancements, challenges remain, such as limited availability, high costs, and the need for further validation in diverse patient populations. Through a comprehensive literature review across databases such as PubMed, Google Scholar, and the Cochrane Library, this study compiles and analyzes data from 18 relevant studies, offering a detailed understanding of the current state of HF biomarkers. The study examines both traditional and emerging biomarkers such as galectin-3 and soluble suppression of tumorigenicity 2 in HF, exploring their clinical roles and impact on patient outcomes.

Hemodialysis and biomarkers of myocardial infarction - a cohort study

OBJECTIVES

End-stage renal disease is associated with a high risk of cardiovascular disease. We compared the concentration and prognostic ability of high sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI) and cardiac myosin-binding protein C (cMyC) among stable hemodialysis patients.

METHODS

Patients were sampled before and after hemodialysis. We measured hs-cTnI, hs-cTnT and cMyC and used Cox regressions to assess the association between quartiles of concentrations and all-cause mortality and a combination of cardiovascular events and all-cause mortality during follow-up.

RESULTS

A total of 307 patients were included, 204 males, mean age 66 years (SD 14). Before dialysis, 299 (99 %) had a hs-cTnT concentration above the 99th percentile, compared to 188 (66 %) for cMyC and 35 (11 %) for hs-cTnI. Hs-cTnT (23 %, p<0.001) and hs-cTnI (15 %, p=0.049) but not cMyC (4 %, p=0.256) decreased during dialysis. Follow-up was a median of 924 days (492-957 days); patients in the 3rd and 4th quartiles of hs-cTnT (3rd:HR 3.0, 95 % CI 1.5-5.8, 4th:5.2, 2.7-9.8) and the 4th quartile of hs-cTnI (HR 3.8, 2.2-6.8) had an increased risk of mortality. Both were associated with an increased risk of the combined endpoint for patients in the 3rd and 4th quartiles. cMyC concentrations were not associated with risk of mortality or cardiovascular event.

CONCLUSIONS

Hs-cTnT was above the 99th percentile in almost all patients. This was less frequent for hs-cTnI and cMyC. High cTn levels were associated with a 3-5-fold higher mortality. This association was not present for cMyC. These findings are important for management of hemodialysis patients.

Proportional troponin changes and risk for outcomes with intervention strategies in non-ST-elevation acute coronary syndrome across kidney function

AIMS

This analysis evaluates whether proportional serial cardiac troponin (cTn) change predicts benefit from an early versus delayed invasive, or conservative treatment strategies across kidney function in non-ST-elevation acute coronary syndrome (NSTE-ACS).

METHODS

Patients diagnosed with NSTE-ACS in the Veterans Health Administration between 1999 and 2022 were categorized into terciles (<20%, 20 to ≤80%, >80%) of proportional change in serial cTn. Primary outcome included mortality or rehospitalization for myocardial infarction at 6 and 12 months, in survivors of index admission. Adjusted hazard ratio (HR) with 95% confidence Intervals (95% confidence interval [CI]) were calculated for the primary outcome for an early invasive (≤24 h of the index admission), delayed invasive (>24 h of index admission to 90-days postdischarge), or a conservative management.

RESULTS

Chronic kidney disease (CKD) was more prevalent (45.3%) in the lowest versus 42.2% and 43% in middle and highest terciles, respectively (p < 0.001). Primary outcome is more likely for conservative versus early invasive strategy at 6 (HR: 1.44, 95% CI: 1.37-1.50) and 12 months (HR: 1.44, 95% CI: 1.39-1.50). A >80% proportional change demonstrated HR (95% CI): 0.90 (0.83-0.97) and 0.93 (0.88-1.00; p = 0.041) for primary outcome at 6 and 12 months, respectively, when an early versus delayed invasive strategy was used, across CKD stages.

CONCLUSIONS

Overall, the invasive strategy was safe and associated with improved outcomes across kidney function in NSTE-ACS. Additionally, >80% proportional change in serial troponin in NSTE-ACS is associated with benefit from an early versus a delayed invasive strategy regardless of kidney function. These findings deserve confirmation in randomized controlled trials.

Implementing screening for myocardial injury in non-cardiac surgery: perspectives of an ad-hoc interdisciplinary expert group

Objectives. Perioperative myocardial injury (PMI) is increasingly recognised as an important complication of non-cardiac surgery, with often clinically silent presentation, but detrimental prognosis. Active screening for PMI, involving the detection of dynamic and elevated levels of cardiac troponin, has recently been advocated by an increasing number of guidelines; however, active PMI screening has not been reflected in clinical practice. Design. As consensus on a common screening and management pathway is lacking, we synthesise the current evidence to provide suggestions on the selection of patients for screening, organisation of a screening program, and a potential management pathway, building upon a recently published perioperative screening algorithm. Results. Screening should be performed using high-sensitivity assays both preoperatively and postoperatively (postoperative Days 1 and 2) in patients at high-risk of experiencing perioperative complications. Conclusion. This expert opinion piece by an interdisciplinary group of predominantly Norwegian clinicians aims to assist healthcare professionals planning to implement guideline-recommended PMI screening at a local level in order to improve patient outcomes following non-cardiac surgery.

A Young Male Presenting With Chest Pain, Elevated Troponin Levels, and a Clinical Dilemma: A Case Report

Chest pain is a common presentation that may represent a wide variety of underlying etiologies ranging from mild self-limiting conditions to immediately life-threatening emergencies. The combination of "cardiac-sounding chest pain" and elevated troponin levels would raise suspicion of an acute ischemic event. An acute coronary syndrome is a diagnosis that may be straightforward; however, oftentimes, patients with elevated troponin levels and chest pain may bring about a state of diagnostic uncertainty. Alternative diagnoses to consider would be inflammatory or infectious conditions of the myocardium and pericardium. We present the case of a young gentleman in his twenties who presents with cardiac chest pain, elevated troponin, and non-specific changes on his electrocardiogram who was treated for an alternative cause of elevated troponin and chest pain, myopericarditis. We present the case of a 24-year-old male who presented with a six-hour history of debilitating retrosternal chest pain. Initial workup showed a Troponin I level greater than 15,000 ng/L, D-Dimer greater than 1,000 mcg/L with no overt ischemic features on electrocardiogram. The patient had no high-risk features in his medical history & denied the use of recreational drugs. A formal same-day echocardiogram revealed normal biventricular systolic function and no evidence of regional wall motion abnormality (RWMA). He was eventually treated clinically for myopericarditis. A Cardiac MRI (CMR) imaging was done to confirm the diagnosis and rule out, most importantly, ischemic heart disease or any other underlying pathology. The main dilemma in this case was working out whether there was indeed peri-myocardial inflammation, or an acute coronary event (such as spontaneous coronary artery dissection) given his age and clinical history. Patients presenting with a very high troponin level, particularly in young patient cohorts, should raise suspicion of a myocardial or pericardial inflammatory process. In addition to a thorough history and in the absence of ischemic changes on the electrocardiogram, subtle findings such as PR segment depression may point to a diagnosis of pericardial inflammation. While urgent echocardiography is useful to quickly assess ventricular function and for RWMA, CMR imaging is the Gold Standard modality of investigation to provide detailed structural information of the heart.

Clinical Utility of Soluble Lectin Type Oxidized Low-Density Lipoprotein Receptor as a Biomarker for Myocardial Infarction and Stable Angina

Background and objectives Endothelial soluble lectin-type oxidized low-density lipoprotein receptor 1 (sLOX-1) recognizes oxidized low-density lipoprotein (LDL) and triggers downstream signaling leading to atherosclerosis. The objective of this study was to demonstrate the utility of sLOX-1 as a biomarker for detecting acute myocardial infarction (MI) and stable angina (SA) and to develop a diagnostic algorithm for distinguishing coronary vasospasm from coronary plaque rupture. Methods We enrolled 62 patients who underwent diagnostic coronary angiography (CAG) and 30 healthy controls (21 men and nine women) and measured sLOX-1, troponin I, and cardiac myosin-binding protein C (c-MyBPC) using commercial kits. Results Patients with MI exhibited higher sLOX-1 levels (301.55 ± 196.16 pg/ml) than patients with stable angina (220.76 ± 103.65 pg/ml) and healthy controls (121.14 ± 77.10, F: 10.55, p<0.001). Although higher troponin I levels were detected in MI patients (263.00 ± 493.00 vs. 3.19 ± 2.15 ng/ml, p=0.0019), no significant elevation was observed in SA patients (1.91 ± 0.79 ng/ml). Plasma sLOX-1 levels showed a positive association with age (r=0.37, p=0.003), but not with gender (r=0.04, p=0.75). Troponin I showed no association with age (r=0.12, p=0.36) or gender (r=0.06, p=0.62). Receiver operating characteristic (ROC) curves revealed that among the three biomarkers, troponin-I showed a higher area under the curve (AUC) (AUC: 0.941), followed by sLOX-1 (AUC: 0.888), while c-MyBPC showed no clinical utility in the detection of MI (AUC: 0.666). Conclusions A marked elevation of sLOX-1 can detect MI and differentiate the presence or absence of plaque rupture, along with diagnosing stable angina.

Upregulation of PCSK9, rho kinase and cardiac troponin by Eucalyptus globulus leaf extract improves fructose-streptozotocin-induced diabetic cardiac dysfunction in rats

CONTEXT

The effect of Eucalyptus globulus in diabetic cardiac dysfunction and the possible mechanisms involved have not been explored.

OBJECTIVE

To evaluate the effect of ethanol leaf extract of E. globulus (NEE) on the cardiac function of fructose/streptozotocin-induced diabetic rats.

MATERIALS AND METHODS

Type-2 diabetes was induced in rats with 10% fructose feeding for 14 days and an intraperitoneal administration of 40 mg/kg streptozotocin. Diabetic animals were treated with NEE (100-400 mg/kg) or 5 mg/kg glibenclamide orally for 21 days. Biochemical assays, histopathological examination and analyses of PCSK9, Rho kinase and Cardiac troponin expression were performed.

RESULTS

The untreated diabetic group showed decreased expression of the genes, oxidative stress, dyslipidemia, increased activities of creatine kinase MB and lactate dehydrogenase, reduced nitric oxide level, and depletion of cardiomyocytes, which were reversed in NEE treated groups.

CONCLUSIONS

Eucalyptus globulus ameliorated diabetic cardiac dysfunction through increased PCSK9, Rho kinase and Cardiac troponin expression.

Acute Myocarditis Following COVID-19 Vaccination in a Young Adult

The mRNA vaccines for coronavirus disease-2019 (COVID-19) have been implemented across the globe for both emergent and non-emergent applications. We present a rare case of myocarditis following the second dosage of COVID-19 vaccine. In this case, myocarditis was suspected by troponin and erythrocyte sedimentation rate (ESR) levels prior to echocardiography, which demonstrated mild pericardial effusion, mild tricuspid regurgitation, and mild asymmetric left ventricular hypertrophy. Mild to moderate symptoms of myocardial inflammation persisted throughout the patient's admission, which attributed to the clinical presentation of chest pain and palpitations. As the patient had no relevant history to account for cardiac pathologies prior to vaccination, this case report serves to further investigate the association between mRNA-derived vaccination and subsequent acute myocarditis development.

False Elevation of Troponin Levels in a Patient With Chest Pain and Significant Psychoemotional Stress

We present a case of a 63-year-old woman who experienced significant psychoemotional stress and was seen in the emergency department for an evaluation of chest pain. She was sent home after reassurance. Subsequent troponin levels came back above the normal range. The patient was called back to the hospital for further assessment, including a potential workup for the exclusion of acute coronary syndrome, given the existing risk factors, symptoms, and elevated cardiac enzymes. The patient has risk factors for atherosclerosis, including hypercholesterolemia, hypertension, and age. She has recently gone through hard personal, emotional, and psychosocial stress. She presented with atypical chest pain, subjective sense of breathlessness, and anxiety. She was reassured, had blood tests ordered, and was discharged after relative improvement. Later that day, her blood test results, which were taken earlier, showed elevated troponin levels. Therefore, she was asked to come back for a cardiology assessment and underwent coronary angiography, which showed normal patent coronary arteries. This case report highlights a patient with a non-cardiac elevation of troponin, emphasizing the importance of considering non-cardiac causes when interpreting elevated troponin levels. The objective of this report is to raise awareness among healthcare professionals regarding the potential causes of false troponin elevation and promote a comprehensive diagnostic approach to minimize unnecessary interventions.

The Role of Biochemical Cardiac Markers in Atrial Fibrillation

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Proteins are a component of cardiac biomarkers containing cell structures that are released into the circulation when a myocardial injury occurs. They are essential in the diagnosis, risk assessment, and treatment of patients who have chest pain, are thought to have acute coronary syndrome, or are experiencing acute heart failure exacerbations. There are numerous biochemical cardiac markers, but this article summarizes the basic role of major biochemical cardiac markers, including cardiac natriuretic peptides, cardiac troponins, C-reactive protein (CRP), creatine kinase-MB, heart-type fatty acid-binding protein, ischemia-modified albumin, lipoprotein (a), osteopontin (OPN), and soluble suppression of tumorigenicity 2 (sST2), in AF. Atrial natriuretic peptide may serve as an indicator of atrial integrity, which may help to select appropriate treatment approaches for AF. Higher levels of N-terminal pro-B-type natriuretic peptide and brain natriuretic peptide are predictive of incidental AF. Increased troponin T release may indicate better clinical results following AF ablation. Similarly, CRP increases the risk of the AF-increasing calcium (Ca) influx in atrial myocytes, but not because of atrial fibrosis. Patients with postoperative AF have lower FABP3 gene expression in the atrium. Lipoprotein (a) (Lp[a]) may play a causative role in the onset of AF and impact various cardiac tissues. Clinical trials for Lp(a)-lowering drugs should assess their impact on preventing AF. Also, OPN was highly expressed in the circulation of AF patients and further increased with the progression of AF. sST2 was a reliable predictor of new-onset AF and can improve the accuracy of the AF risk model. There is a greater chance that these cardiac biomarkers might be employed to enhance clinical risk stratification in AF.

A Cardiovascular Conundrum: A Case of Excessive Exercise Masquerading as a Heart Attack

Cardiac troponins T and I are sensitive biomarkers often associated with acute coronary syndrome but can also be elevated after intense exercise, posing diagnostic challenges. We present the case of a 42-year-old male cyclist who complained of chest pain during exercise with elevated troponin levels. A comprehensive evaluation ruled out cardiac pathology but revealed acid reflux. Excessive cycling posture exacerbates reflux, likely contributing to chest pain and troponin elevation. This case underscores the importance of considering alternative etiologies in athletes with chest pain and elevated troponin levels after extreme exertion. It also highlights the role of antireflux therapy and activity modification in managing such cases. Further research is needed to elucidate the long-term cardiac effects of exercise-induced troponin elevation, although this is currently considered a reversible physiological phenomenon.

Cardiac Troponin, Kidney Function, Heart Failure and Mortality After Myocardial Infarction in Patients With and Without Kidney Impairment

Cardiac troponins (cTn) are routinely measured for the diagnosis and prognosis of myocardial infarction (MI). The relation between troponin levels, estimated glomerular filtration rate (eGFR), postinfarction heart failure (HF), and mortality is unclear in patients with kidney impairment. This is a retrospective, cross-sectional study of patients presenting to the Emergency Department at a single tertiary center. Participants presenting with confirmed type I MI from January 1, 2019, to December 31, 2021, were analyzed from the Myocardial Ischemia National Audit Project database. Main outcomes were acute HF, measured using Killip class, and inpatient mortality. Peak cardiac troponin T (cTnT) level was a secondary outcome. Data on 2,815 patients (67±14 years, 28% female) were analyzed. Ordinal logistic regression analysis was used to test for predictors of increasing Killip class. Binary logistic regression was used to test for predictors of inpatient mortality. Analysis of a sub-sample matched for age and diabetes mellitus status showed increased mortality in patients with eGFR <60 ml/min/1.73 m2 (12.2% vs 4.4%, p <0.001). Multivariate predictors of acute HF included log-transformed peak cTnT, eGFR, body mass index (BMI), and diabetes mellitus status. Multivariate predictors of inpatient mortality included log-transformed peak cTnT, eGFR, age, BMI, and Killip class 3/4. On multivariate analysis, eGFR, ST-elevation MI diagnosis, BMI, male gender, diabetes mellitus status, and hypertension were all predictive of peak cTnT after MI. In conclusion, peak cTnT level and eGFR at presentation after MI are independent predictors of acute HF severity and death in patients with and without kidney impairment.

Diagnoses and Outcomes of Patients with Suspicion of Acute Coronary Syndrome and Raised High Sensitive Troponin I: A Single Center Study from Pakistan

Objectives  Troponins are classically raised in acute coronary syndrome (ACS) although other cardiovascular and non-cardiovascular causes are recognized. We aimed to see the association of high sensitivity (Hs) Troponin I values exceeding the sex-specific 99th percentile upper reference limit (URL) with diagnoses, emergency department (ED) outcomes, 30-day outcomes of admitted patients and predictors of ACS in both genders. Materials and Methods  A retrospective study of all patients presenting to the emergency department from January 2019 to April 2021 with suspicion of ACS and Hs-Troponin I values greater than the sex-specific 99th percentile URL. Statistical Analysis  SPSS version 24 was used, Pearson's chi-square tests, Fisher's exact test, Kruskal-Wallis test, Mann-Whitney U test, and odds ratios, including the 95% confidence intervals, for each characteristic were used for analysis. A p -value of < 0.05 was considered significant. Results  There were a total of 5,982 patients (3,031 males, 2,951 females), out of which 878 patients were admitted under the cardiology specialty. In patients who were admitted to the ward, mortality was higher in females (8.2%) with less than a 10-fold rise in Hs-Troponin I while similar in both genders (7.6%) in patients with Hs-troponin I greater than 10-fold of sex-specific 99th percentile URL. Raised low-density lipoprotein-cholesterol was a significant factor associated with 2.4 times higher odds of ACS. Conclusion  Women with Hs-Troponin values up to 10 times the URL, i.e., 15.6-160 ng/L have higher mortality than their male counterparts. LDL-cholesterol is a significant risk factor for ACS which should be controlled for its prevention.

High-Sensitivity Cardiac Troponin for Risk Assessment in Patients With Chronic Coronary Artery Disease

BACKGROUND

Cardiac troponin is used for risk stratification of patients with acute coronary syndromes; however, the role of testing in other settings remains unclear.

OBJECTIVES

The aim of this study was to evaluate whether cardiac troponin testing could enhance risk stratification in patients with chronic coronary artery disease independent of disease severity and conventional risk measures.

METHODS

In a prospective cohort of consecutive patients with symptoms suggestive of stable angina attending for outpatient coronary angiography, high-sensitivity cardiac troponin I was measured before angiography, and clinicians were blinded to the results. The primary outcome was myocardial infarction or cardiovascular death during follow-up.

RESULTS

In 4,240 patients (age 66 years [IQR: 59-73 years], 33% female), coronary artery disease was identified in 3,888 (92%) who had 255 (6%) primary outcome events during a median follow-up of 2.4 years (IQR: 1.3-3.6 years). In patients with coronary artery disease, troponin concentrations were 2-fold higher in those with an event compared with those without (6.7 ng/L [IQR: 3.2-14.2 ng/L] vs 3.3 ng/L [IQR: 1.7-6.6 ng/L]; P < 0.001). Troponin concentrations were associated with the primary outcome after adjusting for cardiovascular risk factors and coronary artery disease severity (adjusted HR: 2.3; 95% CI: 1.7-3.0, log10 troponin; P < 0.001). A troponin concentration >10 ng/L identified patients with a 50% increase in the risk of myocardial infarction or cardiovascular death.

CONCLUSIONS

In patients with chronic coronary artery disease, cardiac troponin predicts risk of myocardial infarction or cardiovascular death independent of cardiovascular risk factors and disease severity. Further studies are required to evaluate whether routine testing could inform the selection of high-risk patients for treatment intensification. (Myocardial Injury in Patients Referred for Coronary Angiography [MICA]; ISRCTN15620297).

The Influence of Body Mass Index on Clinical Interpretation of Established and Novel Biomarkers in Acute Heart Failure

BACKGROUND

Body mass index (BMI) is a known confounder for natriuretic peptides, but its influence on other biomarkers is less well described. We investigated whether BMI interacts with biomarkers' association with prognosis in patients with acute heart failure (AHF).

METHODS AND RESULTS

B-type natriuretic peptide (BNP), high-sensitivity cardiac troponin I (hs-cTnI), galectin-3, serum neutrophil gelatinase-associated lipocalin (sNGAL), and urine NGAL were measured serially in patients with AHF during hospitalization in the AKINESIS (Acute Kidney Injury Neutrophil gelatinase-associated lipocalin Evaluation of Symptomatic Heart Failure) study. Cox regression analysis was used to determine the association of biomarkers and their interaction with BMI for 30-day, 90-day and 1-year composite outcomes of death or HF readmission. Among 866 patients, 21.2%, 29.7% and 46.8% had normal (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2) or obese (≥ 30 kg/m2) BMIs on admission, respectively. Admission values of BNP and hs-cTnI were negatively associated with BMI, whereas galectin-3 and sNGAL were positively associated with BMI. Admission BNP and hs-cTnI levels were associated with the composite outcome within 30 days, 90 days and 1 year. Only BNP had a significant interaction with BMI. When BNP was analyzed by BMI category, its association with the composite outcome attenuated at higher BMIs and was no longer significant in obese individuals. Findings were similar when evaluated by the last-measured biomarkers and BMIs.

CONCLUSIONS

In patients with AHF, only BNP had a significant interaction with BMI for the outcomes, with its association attenuating as BMI increased; hs-cTnI was prognostic, regardless of BMI.

Analysis of Sensitivity, Specificity, and Predictive Values of High-Sensitivity Troponin T in a Secondary Care Setting: A Retrospective Cohort Study

Background High-sensitivity cardiac troponin (hs-cTn) assays have significantly improved the early detection of myocardial injury and the diagnosis of acute coronary syndrome (ACS). Different diagnostic algorithms exist for the interpretation of hs-cTn in the management of patients with suspected ACS. This study analysed the diagnostic efficacy of hs-cTn using serial and single measurements while also shedding light on the challenges associated with the use of this assay. Methods  We reviewed 189 results belonging to 120 unique patient episodes and records for troponin tests performed in a two-week period obtained from the West Cumberland Hospital, North Cumbria Integrated Care (NCIC), Whitehaven, England. These troponin tests were carried out based on the NCIC trust guidelines for the use of troponin assays in the management of acute coronary syndrome (ACS). A positive troponin test is defined using the NCIC trust guidelines and the National Academy of Clinical Biochemistry (NACB) guidelines. The case notes of the unique patients were reviewed to determine the outcome, which is defined as the clinical diagnosis on discharge of the patient following a cardiologist review. These outcomes were then used to calculate the sensitivity, specificity, and predictive values. We also determined the alternate diagnosis for false-positive tests. Results Using both guidelines to assess the clinical effectiveness of the troponin assay yields slightly varying results, with the single positive test of NACB demonstrating a higher sensitivity of 92.8% (>71.4%) and a slightly better negative predictive value of 97.8% (>96%). However, using the serial troponin measurements as per the NCIC trust guideline demonstrates a better specificity of 95.2% (>42.4%) and a positive predictive value of 66% (>17.5%). False positive results are identified, which are due to alternate diagnoses such as stable angina, myocarditis, heart failure, sepsis, and malignancy. Conclusion  High-sensitivity troponin (hs-cTn) assays play a crucial role in the early detection and management of patients with suspected ACS. This study supports evidence that serial troponin measurements are more diagnostically accurate than single troponin measurements. Although hs-cTn assays offer significant advantages, there remain challenges and limitations that require careful interpretation and clinical correlation.

Antibody-mediated interferences affecting cardiac troponin assays: recommendations from the IFCC Committee on Clinical Applications of Cardiac Biomarkers

The International Federation of Clinical Chemistry Committee on Clinical Applications of Cardiac Biomarkers (IFCC C-CB) provides educational documents to facilitate the interpretation and use of cardiac biomarkers in clinical laboratories and practice. Our aim is to improve the understanding of certain key analytical and clinical aspects of cardiac biomarkers and how these may interplay. Measurements of cardiac troponin (cTn) have a prominent place in the clinical work-up of patients with suspected acute coronary syndrome. It is therefore important that clinical laboratories know how to recognize and assess analytical issues. Two emerging analytical issues resulting in falsely high cTn concentrations, often several fold higher than the upper reference limit (URL), are antibody-mediated assay interference due to long-lived cTn-antibody complexes, called macrotroponin, and crosslinking antibodies that are frequently referred to as heterophilic antibodies. We provide an overview of antibody-mediated cTn assay interference and provide recommendations on how to confirm the interference and interpret the results.

Association Between COVID-19 Infection and Cardiac Biomarkers in Hospitalized Patients at a Tertiary Care Center

Background The effects of coronavirus disease 2019 (COVID-19) on the cardiovascular system are well established. However, knowledge gaps in the clinical implications of cardiac involvement in COVID-19 patients are yet to be addressed. This study aimed to investigate acute cardiac injury (ACI) risk factors and outcomes associated with COVID-19 infection with cardiac involvement. Methodology In this retrospective study, we included hospitalized patients between March 2020 and May 2022 with confirmed COVID-19 infection and evidence of cardiac involvement. Results In total, 501 patients were included, of whom 396 (79%) had evidence of ACI. The median troponin level was 25.8 (interquartile range (IQR) = 10.8-71). Patients with evidence of ACI were significantly more likely to have diabetes mellitus (75% vs. 60%), cardiovascular disease (48% vs. 37%), chronic lung disease (22.2% vs. 12.4%), and chronic kidney disease (32.3% vs. 16.2%). Additionally, patients with ACI were significantly more likely to have cardiomegaly (60.6% vs. 44.8%) and bilateral lobe infiltrates (77.8% vs. 60%) on X-ray. Patients with ACI were significantly more likely to suffer from complications such as cardiogenic shock (5.3% vs. 0%), pneumonia (80.1% vs. 65.7%), sepsis (24.2% vs. 9.5%), and acute respiratory distress syndrome (33.1% vs. 8.6%). Patients with ACI were also significantly more likely to be admitted to the intensive care unit (ICU) (57% vs. 26.7%) and significantly more likely to die (38.1% vs. 11.4%). The results of the multivariate regression analysis indicated that mortality was significantly higher in patients with elevated troponin levels (adjusted odds ratio = 4.73; 95% confidence interval = 2.49-8.98). Conclusions In COVID-19-infected patients, old age, diabetes mellitus, cardiovascular disease, chronic lung disease, and chronic kidney disease were associated with an increased risk of ACI. The presence of ACI in the context of COVID-19 infection was noted to increase the risk for severe complications, such as cardiogenic shock, ICU admission, sepsis, and death.

Using logistic regression models to investigate the effects of high-sensitivity cardiac troponin T confounders on ruling in acute myocardial infarction

OBJECTIVES

Confounding factors, including sex, age, and renal dysfunction, affect high-sensitivity cardiac troponin T (hs-cTnT) concentrations and the acute myocardial infarction (AMI) diagnosis. This study assessed the effects of these confounders through logistic regression models and evaluated the diagnostic performance of an optimized, integrated prediction model.

METHODS

This retrospective study included a primary derivation cohort of 18,022 emergency department (ED) patients at a US medical center and a validation cohort of 890 ED patients at a Canadian medical center. Hs-cTnT was measured with 0/3 h sampling. The primary outcome was index AMI diagnosis. Logistic regression models were optimized to predict AMI using delta hs-cTnT and its confounders as covariates. The diagnostic performance of model cutoffs was compared to that of the hs-cTnT delta thresholds. Serial logistic regressions were carried out to evaluate the relationship between covariates.

RESULTS

The area under the curve of the best-fitted model was 0.95. The model achieved a 90.0% diagnostic accuracy in the validation cohort. The optimal model cutoff yielded comparable performance (90.5% accuracy) to the optimal sex-specific delta thresholds (90.3% accuracy), with 95.8% agreement between the two diagnostic methods. Serial logistic regressions revealed that delta hs-cTnT played a more predominant role in AMI prediction than its confounders, among which sex is more predictive of AMI (total effect coefficient 1.04) than age (total effect coefficient 0.05) and eGFR (total effect coefficient -0.008).

CONCLUSIONS

The integrated prediction model incorporating confounding factors does not outperform hs-cTnT delta thresholds. Sex-specific hs-cTnT delta thresholds remain to provide the highest diagnostic accuracy.

Stroke-heart syndrome: A case report and mini literature review

Despite the fact that cardiac troponin (cTn) elevation is commonly seen in the acute phase of ischemic stroke, investigating its etiology represents a challenge for healthcare practitioners. Therefore, we describe the case of an 86-year-old woman with dyspnea and cTn-elevation within the first days following acute ischemic stroke and discuss potential differential diagnoses and diagnostic dilemmas.

Non-ST Segment Elevation Myocardial Infarction (NSTEMI) in the Setting of Severe Rhabdomyolysis and COVID-19 Infection: A Case Report

We present a case report of a non-ST segment elevation myocardial infarction (NSTEMI) occurring in an 89-year-old male with severe rhabdomyolysis and COVID-19 infection. The patient had a complex medical history, including non-ischemic cardiomyopathy, sinus bradycardia status post permanent pacemaker placement, and multiple comorbidities. He presented to the emergency department after a mechanical fall and was found to be COVID-19 positive. Despite the absence of typical symptoms, the patient's elevated troponin levels and electrocardiogram findings indicated NSTEMI. The initial management included an acute coronary syndrome protocol and admission to the cardiac intensive care unit. During the hospitalization, the patient developed acute hypoxic respiratory failure and was treated for COVID-19 pneumonia. The patient's renal function and creatine kinase levels showed improvement, and cardiac catheterization revealed non-obstructive coronaries. The patient was discharged in stable condition with a follow-up scheduled.

Subclinical Cardiovascular Disease in US Adults With and Without Diabetes

Background We characterized the burden and prognostic value of subclinical cardiovascular disease (CVD) assessed by cardiac biomarkers among adults with and without diabetes in the general US population. Methods and Results We measured hs-cTnT (high-sensitivity cardiac troponin T) and NT-proBNP (N-terminal pro-B-type natriuretic peptide) in stored serum samples from the 1999 to 2004 National Health and Nutrition Examination Survey. Among US adults without a history of CVD (n=10 304), we estimated the prevalence of elevated hs-cTnT (≥14 ng/L) and NT-proBNP (≥125 pg/mL) in those with and without diabetes. We examined the associations between elevated hs-cTnT and NT-proBNP with all-cause and CVD mortality after adjustment for demographics and traditional CVD risk factors. The crude prevalence of subclinical CVD (elevated hs-cTnT or NT-proBNP) was ≈2 times higher in adults with (versus without) diabetes (33.4% versus 16.1%). After age adjustment, elevated hs-cTnT, but not elevated NT-proBNP, was more common in those with diabetes, overall and across age, sex, race and ethnicity, and weight status. The prevalence of elevated hs-cTnT was significantly higher in those with longer diabetes duration and worse glycemic control. In persons with diabetes, elevated hs-cTnT and NT-proBNP were independently associated with all-cause mortality (adjusted hazard ratio [HR], 1.77 [95% CI, 1.33-2.34] and HR, 1.78 [95% CI, 1.26-2.51]) and CVD mortality (adjusted HR, 1.54 [95% CI, 0.83-2.85] and HR, 2.46 [95% CI, 1.31-4.60]). Conclusions Subclinical CVD affects ≈1 in 3 US adults with diabetes and confers substantial risk for mortality. Routine testing of cardiac biomarkers may be useful for assessing and monitoring risk in persons with diabetes.

Frequencies of Anti-Troponin I vs Anti-Troponin T Autoantibodies and Degrees of Interference on Troponin Assays

OBJECTIVE

Presence of autoantibodies against troponin I (cTnI) or T (cTnT) has been reported to interfere with troponin assays. However, the extent of the interference with the measurement has not been explored sufficiently. The aims of this study were to examine the frequencies of autoantibodies against troponin I and troponin T and how much these antibodies would affect the measurement.

METHODS

The study comprised 52 subjects who visited Hokkaido University Hospital with suspected ischemic heart diseases. To evaluate the presence of autoantibodies, we calculated the recoveries of cTnI or cTnT after immunoglobulin G depletion, and the distributions of peaks reactive with cTnI or cTnT by high-performance liquid chromatography were examined.

RESULTS

Autoantibodies against cTnI and cTnT were identified in 8 subjects (15.4%) and 1 subject (1.9%), respectively. Although the greatest difference between cTnI and cTnT was 32-fold, the distributions of cTnI-to-cTnT ratios in groups with and without anti-cTnI were not statistically different.

CONCLUSION

Autoantibodies against cTnI were more frequent by several fold than those against cTnT. Their presence did not significantly expand the discrepancy between cTnI and cTnT assays.

An Unexpected Cause of Chest Pain While Self-Pleasuring: A Ripping Doom Excitement

Acute aortic dissection (AD) involves the tearing of the aortic intima by shearing forces, resulting in a false lumen, which, depending on its location and extent, may lead to hemodynamic compromise, hypoperfusion of vital organs, or even rupture of the aorta. The classical presentation is a sudden chest or back pain described as sharp or ripping in quality. We present a 60-year-old male with a history of hypertension, Liddle's syndrome, obstructive sleep apnea, and chronic cannabis use for insomnia who arrived at a non-PCI hospital complaining of severe retrosternal chest pain lasting several hours in evolution that started upon masturbation. The pain was ripping in character, starting retrosternally and radiating to his neck and back. After evidence of rising troponin values, he was initially diagnosed with non-ST segment elevation myocardial infarction (NSTEMI), managed with dual antiplatelet therapy with full anticoagulation, and subsequently transferred to our institution for further care. Shortly after his arrival at our hospital, he suddenly deteriorated with recurrent chest pain and hypotension, which triggered an emergent bedside echocardiogram evaluation. This revealed a hemodynamically significant pericardial effusion, moderate to severe aortic valve regurgitation (AR), and an intimal flap visualized on the ascending and descending aorta, suggestive of an extensive AD. A computerized tomographic angiogram confirmed the diagnosis of a Stanford type A AD that required an emergent surgical pericardiotomy, ascending aorta with partial arch replacement, and aortic valve repair. Often, AD may mimic an acute coronary syndrome (ACS) or even present with an acute myocardial infarction (AMI). The appropriate diagnostic imaging evaluation prior to the initiation of anticoagulation therapy should be done in patients with higher-risk clinical criteria for AD to reduce adverse treatment outcomes. The use of a simple three-step diagnostic algorithm for acute aortic syndromes (AAS) may decrease diagnostic delays, misdiagnosis, and inappropriate therapies.

Chronic troponin elevation assessed by myocardial T1 mapping in patients with stable coronary artery disease

BACKGROUND

Cardiac troponin detected with sensitive assays can be chronically elevated, in the absence of unstable coronary syndromes. In patients with chronic coronary artery disease, clinically silent ischemic episodes may cause chronic troponin release. T1 mapping is a cardiovascular magnetic resonance technique useful in quantitative cardiac tissue characterization. We selected patients with anatomically and functionally normal hearts to investigate associations between chronic troponin release and myocardial tissue characteristics assessed by T1 mapping.

METHODS

We investigated the relationship between cardiac troponin I concentrations and cardiovascular magnetic resonance T1 mapping parameters in patients with stable coronary artery disease enrolled in MASS V study before elective revascularization. Participants had no previous myocardial infarction, negative late gadolinium enhancement, normal left ventricular function, chamber dimensions and wall thickness.

RESULTS

A total of 56 patients were analyzed in troponin tertiles: nativeT1 and extracellular volume (ECV) values (expressed as means ± standard deviations) increased across tertiles: nativeT1 (1006 ± 27 ms vs 1016 ± 27 ms vs 1034 ± 37 ms, ptrend = 0.006) and ECV (22 ± 3% vs 23 ± 1.9% vs 25 ± 3%, ptrend = 0.007). Cardiac troponin I concentrations correlated with native T1(R = 0.33, P = .012) and ECV (R = 0.3, P = .025), and were independently associated with nativeT1 (P = .049) and ventricular mass index (P = .041) in multivariable analysis.

CONCLUSION

In patients with chronic coronary artery disease and structurally normal hearts, troponin I concentrations correlated with T1 mapping parameters, suggesting that diffuse edema or fibrosis scattered in normal myocardium might be associated with chronic troponin release.

Extensive CArdioVAscular Characterization and Follow-Up of Patients Receiving Immune Checkpoint Inhibitors: A Prospective Multicenter Study

BACKGROUND

The increasing use of immune checkpoint inhibitors (ICIs) in the treatment of both advanced and early stages of various malignancies has resulted in a substantial increase in the incidence of cardiovascular (CV) immune-related adverse events (irAEs). The current follow-up guidelines are based on anecdotal evidence and expert opinions, due to a lack of solid data and prospective studies. As many questions remain unanswered, cardiac monitoring, in patients receiving ICIs, is not always implemented by oncologists. Hence, an urgent need to investigate the possible short- and long-term CV effects of ICIs, as ICI approval is continuing to expand to the (neo)adjuvant setting.

METHODS

We have initiated a prospective, multicenter study, i.e., the CAVACI trial, in which a minimum of 276 patients with a solid tumor, eligible for ICI treatment, will be enrolled. The study consists of routine investigations of blood parameters (troponin and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, in particular) and a thorough CV follow-up (electrocardiograms, transthoracic echocardiograms, and coronary calcium scoring) at fixed time points for a total period of two years. The primary endpoint is the cumulative incidence of troponin elevation in the first three months of ICI treatment, compared to baseline levels. Furthermore, secondary endpoints include incidence above the upper limit of normal of both troponin and NT-proBNP levels, evolution in troponin and NT-proBNP levels, the incidence of CV abnormalities/major adverse cardiac events, evaluation of associations between patient characteristics/biochemical parameters and CV events, transthoracic echocardiography parameters, electrocardiography parameters, and progression of coronary atherosclerosis. Recruitment of patients started in January 2022. Enrolment is ongoing in AZ Maria Middelares, Antwerp University Hospital, AZ Sint-Vincentius Deinze, and AZ Sint-Elisabeth Zottegem.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05699915, registered 26 January 2023.

Effect of Training Load on Post-Exercise Cardiac Biomarkers in Healthy Children and Adolescents: A Systematic Review of the Existing Literature

BACKGROUND

Postexercise release of cardiac biomarkers (cardiac troponins, cTn, and N-terminal pro b-type natriuretic peptide, NT-proBNP) is a well-known phenomenon in adults, although it remains unclear how it manifests in children. The aim of this review is to compare the pre-exercise with the post-exercise measurement of serum cardiac biomarkers, as well as to analyze their post-exercise release based on age, sex, and exercise intensity and duration.

METHODS

The terms troponin, football, swimmers, marathon, run, and exercise were used in a literature search at National Library of Medicine. The search was further refined by adding the keywords athletes, children, adolescents, and sport.

RESULTS

Fifteen pediatric studies and four studies with a mixed population of adults and children totaled 19 studies for the final analysis. In addition to them, some adult studies have been included for comparison. The kinetics of the cTn and NT-proBNP response after exercise have been the subject of our interest. While the impact of sport type, age, and sex has not yet been fully characterized, the existing data points to considerable impacts of sport intensity and duration on post-exercise biomarkers elevation. Most of the findings came from endurance sports, but the evidence is sparse. Furthermore, there is only limited data on women and less on young adults, African Caribbeans, and professional athletes.

CONCLUSIONS

Both amateur and competitive athletes can exhibit post-exercise release of both cTn and NT-proBNP. This is transient and lacks pathological significance, in contrast with adult population, in which exercise-induced increases in in these biomarker levels may not always be benign. While NT-proBNP release is still primarily driven by activity duration, cTnT release is additionally affected by exercise intensity. To define individual ranges of normality for postexercise cTn and NT-proBNP elevation, the role of several confounders (age, sex, sport type/intensity etc.) remains to be further elucidated.

Judging the clinical suitability of analytical performance of cardiac troponin assays

New millennium diagnostic criteria for acute myocardial infarction precipitated a revolutionary shift from an approach based primarily on electrocardiography and clinical symptoms to a strategy based on biomarkers, and preferably cardiac troponins (cTn) I and T. In the last 20 years, clinical recommendations have strengthened the role of cTn and led to the development of highly sensitive (hs-cTn) assays, which are now leading players in all current clinical practice guidelines. To optimize the clinical use of these hs-cTn assays, focus on their analytical aspects has become increasingly important, emphasizing the need for the establishment of suitable analytical performance by the definition and implementation of appropriate specifications. An accurate estimate of measurement uncertainty, together with the acquisition of the highest analytical quality when very low concentrations of hs-cTn are measured, are essential requirements and should represent a practical laboratory standard in assuring optimal clinical use. Additional goals for further improving the quality of laboratory information should be the establishment of robust data concerning biological variation of cTn and the resolution of practical challenges opposed to the harmonization of cTn I results obtained by differing commercial measuring systems.

Development and validation of nomogram models to discriminate between acute aortic syndromes and non-ST-elevation myocardial infarction during troponin-blind period

Background

Blood-test-based methods of distinguishing between acute aortic syndromes (AASs) and non-ST-elevation myocardial infarction (NSTEMI) during the troponin-blind period of <2-3 h of symptom onset have not been studied previously. We aimed to explore whether routine biomarkers might facilitate differential diagnosis.

Methods

Data were retrospectively collected from 178 patients with AASs and 460 patients with NSTEMI within 3 h of onset. Differential risk factors related to AASs were identified by univariate and multivariate logistic regression analyses for patients with onset <2 h and onset ≥2 h, respectively, in the cardiac troponin (cTn) cohort. Nomograms were established in the cTn cohort as a training set and validated in the high-sensitivity cTn cohort. To assess the utility of the models in clinical practice, decision curve analyses were performed.

Results

D-dimer, fibrinogen, and age were identified as differential risk factors for AASs with the onset of <2 h. D-dimer at an optimal cutoff level of 281 ng/mL for AASs had a sensitivity of 86.4% and a specificity of 91.3%. A nomogram was developed and validated with areas under the curve (AUC) of 0.934 (95% CI: 0.880-0.988) and 0.952 (95% CI: 0.874-1.000), respectively. D-dimer, neutrophil, bilirubin, and platelet were the differential risk factors for AASs with the onset of ≥2 h. D-dimer at an optimal cutoff level of 385 ng/mL has a sensitivity of 91.8% and a specificity of 91.3%. The AUC of the second nomogram in the training set and the validation set were 0.965 (95% CI: 0.942-0.988) and 0.974 (95% CI: 0.944-1.000), respectively.

Conclusion

Time-dependent quality of D-dimer should be considered for discriminating AASs from NSTEMI. Both nomogram models may have a clinical utility for evaluating the probability of AASs.

Macrotroponins cause discrepancy in high-sensitivity examination

AIM

We present two cases with clearly discrepant results of clinical examination and cardiac troponin I (cTnI) and cardiac troponin T (cTnT) concentrations. In similar cases with discrepant results, the possibility of interference should be considered.

METHODS

Due to the suspicion of the presence of macrotroponin I in both of the presented cases, the patients were invited to our laboratory and both cTnI (Architect i1000, Abbott) and cTnT (Cobas 8000, Roche) concentrations were analysed. The samples were treated by preincubation in a heterophilic antibodies blocking tube (HBT) and analysed. Precipitation with polyethylene glycol solution (PEG) and molecular weight separation by gel filtration on Sephadex G100 was performed and concentrations of cTnI were analysed.

RESULTS

In the same blood sample, the cTnT and cTnI concentrations were 7 and 1782 ng/L, respectively, in Case 1, and 6 and 96 ng/L, respectively, in Case 2. Incubation of samples in HBT had no significant effect. CTnI concentrations after precipitation with PEG - presented as the percentage of initial concentrations - were 7.4% in Case 1 (and 26.8% in the control sample) and 1.4% in Case 2 (and 56.0% in the control sample). These results indicate a significant decrease in both cases, supporting presence of macrotroponin I. Finally, analyses of cTnI concentrations after gel filtration also supported the presence of macrotroponin I.

CONCLUSION

The present cases show that the presence of macrotroponin can lead to unnecessary investigation of the patient. When the possibility of interference is suspected, cooperation with laboratory staff to help with interpretation or to perform more detailed analysis is crucial.

A Case Report of Cannabis Abuse: A Surprising Etiology of Elevated Troponin

Cannabis is the most commonly used additive drug after alcohol and tobacco. There has been literature proving the relationship between cannabis use and elevated troponin from myocardial infarction, with many mechanisms explaining them. However, limited data are available on elevated troponin due to cannabis-induced high myocardial oxygen demand due to vasospasm. We present a case of a 21-year-old female presenting with chest pain after cannabis abuse. She exhibited a steep rise in troponin with a normal electrocardiogram (EKG). She refused a coronary angiogram, but a bedside echocardiogram showed no wall motion abnormality. Therefore, the dramatic rise of troponin levels with the chest pain and the resolution of the symptoms were most likely explained by demand ischemia via the mechanism of reversible vasospasm.

Herpes and Chest Pain: Two Atypical Monkeypox Cases

The 2022 Monkeypox Outbreak has spread globally in just a few months and has raised great concerns regarding disease recognition due to frequent atypical presentations and questions regarding the possibility of sexual transmission. In endemic countries and prior outbreaks, the clinical manifestations of monkeypox have been well documented, with cutaneous findings following a set, synchronous pattern of evolution. We present two cases of atypical monkeypox presentations in individuals living with HIV, both complicated by herpes simplex virus type 2 (HSV-2) coinfection and elevated troponins, and both demonstrating the ease with which monkeypox can be overlooked in the current outbreak.

Clinical Profile of Patients with Hypertensive Emergency Referred to a Tertiary Hospital in the Western Cape Province of South Africa

BACKGROUND

Despite advances in managing hypertension, hypertensive emergencies remain a common indication for emergency room visits. Our study aimed to determine the clinical profile of patients referred with hypertensive emergencies.

METHODS

We conducted an observational study involving patients aged ≥18 years referred with hypertensive crisis. A diagnosis of hypertensive emergencies was based on a systolic blood pressure (BP) ≥180 mmHg and/or a diastolic BP ≥110 mmHg, with acute hypertension-mediated organ damage (aHMOD). Patients without evidence of aHMOD were considered hypertensive urgencies. Hypertensive disorders of pregnancy and unconscious patients were excluded from the study.

RESULTS

Eighty-two patients were included, comprising 66 (80.5%) with hypertensive emergencies and 16 (19.5%) with hypertensive urgencies. The mean age of patients with hypertensive emergencies was 47.9 (13.2) years, and 66.7% were males. Age, systolic BP, and duration of hypertension were similar in the hypertensive crisis cohort. Most patients with hypertensive emergencies reported nonadherence to medication (78%) or presented de novo without a prior diagnosis of hypertension (36%). Cardiac aHMOD (acute pulmonary edema and myocardial infarction) occurred in 66%, while neurological emergencies (intracranial hemorrhage, ischemic stroke, and hypertensive encephalopathy) occurred in 33.3%. Lactate dehydrogenase (LDH) (P < 0.001), NT-proBNP (P=0.024), and cardiac troponin (P<0.001) were higher in hypertensive emergencies compared to urgencies. LDH did not differ in the subtypes of hypertensive emergencies.

CONCLUSION

Cardiovascular and neurological emergencies are the most common hypertensive emergencies. Most patients reported nonadherence to medication or presented de novo without a prior diagnosis of hypertension.

The Dilemma Behind Negative Troponin: A Case Report

Acute coronary syndrome remains the primary cause of mortality and morbidity in the United States. Cardiac ischemia is a consequence of an imbalance between oxygen demand and supply. The sensitivity of troponin is above 99% in diagnosing cardiac injury; rare exceptions can occur, however. We present a case of acute coronary syndrome with a negative troponin level, even on repeated testing using different methods at two different centers.

Phosphorylation-dependent interactions of myosin-binding protein C and troponin coordinate the myofilament response to protein kinase A

PKA-mediated phosphorylation of sarcomeric proteins enhances heart muscle performance in response to β-adrenergic stimulation and is associated with accelerated relaxation and increased cardiac output for a given preload. At the cellular level, the latter translates to a greater dependence of Ca2+ sensitivity and maximum force on sarcomere length (SL), that is, enhanced length-dependent activation. However, the mechanisms by which PKA phosphorylation of the most notable sarcomeric PKA targets, troponin I (cTnI) and myosin-binding protein C (cMyBP-C), lead to these effects remain elusive. Here, we specifically altered the phosphorylation level of cTnI in heart muscle cells and characterized the structural and functional effects at different levels of background phosphorylation of cMyBP-C and with two different SLs. We found Ser22/23 bisphosphorylation of cTnI was indispensable for the enhancement of length-dependent activation by PKA, as was cMyBP-C phosphorylation. This high level of coordination between cTnI and cMyBP-C may suggest coupling between their regulatory mechanisms. Further evidence for this was provided by our finding that cardiac troponin (cTn) can directly interact with cMyBP-C in vitro, in a phosphorylation- and Ca2+-dependent manner. In addition, bisphosphorylation at Ser22/Ser23 increased Ca2+ sensitivity at long SL in the presence of endogenously phosphorylated cMyBP-C. When cMyBP-C was dephosphorylated, bisphosphorylation of cTnI increased Ca2+ sensitivity and decreased cooperativity at both SLs, which may translate to deleterious effects in physiological settings. Our results could have clinical relevance for disease pathways, where PKA phosphorylation of cTnI may be functionally uncoupled from cMyBP-C phosphorylation due to mutations or haploinsufficiency.

Association between insomnia phenotypes and subclinical myocardial injury: The Multi-Ethnic Study of Atherosclerosis

STUDY OBJECTIVES

To assess whether the association between insomnia and subclinical myocardial injury, as measured by cardiac troponin T (cTnT), differs across insomnia phenotypes.

METHODS

We measured cTnT in 2188 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) study who had completed sleep questionnaires and undergone unattended polysomnography (PSG) and 7-day actigraphy. Insomnia symptoms were defined as reporting at least one of the following ≥5 nights/week over the past four weeks: trouble falling asleep, waking up several times a night, having trouble getting back to sleep after you woke up too early or taking sleeping pills to help them sleep. OSA was defined as an apnea hypopneas index (AHI) >15. Participants were classified into insomnia phenotypes, including comorbid insomnia and OSA (COMISA) and insomnia associated with actigraphy estimated short sleep (<6hrs) or sleep fragmentation.

RESULTS

The mean age was 68.6 years (SD 9.2), 53.6% were male. 47.8% met threshold levels for insomnia symptoms, and 43.1% had an AHI >15. In adjusted linear regression models COMISA (ß 0.08 (SE 0.03), p<0.01) or insomnia with short sleep duration (ß 0.07 (SE 0.03), p<0.05) were each associated with higher cTnT compared to a reference group with no insomnia. Insomnia with fragmented sleep (ß 0.03 (SE 0.02)) was not associated with higher cTnT (p>0.05) in adjusted analyses. OSA was associated with higher cTnT (ß 0.09 (SE 0.03), p<0.01) in adjusted models.

CONCLUSIONS

COMISA and insomnia with short sleep duration, but not insomnia symptoms alone or fragmented sleep, were associated with increased circulating cTnT in older adults.

Longitudinal Strain and Troponin I Elevation in Patients Undergoing Immune Checkpoint Inhibitor Therapy

Background

Immune checkpoint inhibitors (ICIs) are a central part of cancer therapy; however, cardiac complications, such as myocarditis, have the potential for significant morbidity and mortality. Within this population, the clinical significance of longitudinal strain (LS) remains unknown.

Objectives

This study sought to define the changes in LS in ICI-treated patients, and their associations with high-sensitivity troponin I (hsTnI) and myocarditis.

Methods

We conducted a retrospective cohort study of patients who received ICIs at our hospital from April 2017 to September 2021. All patients underwent echocardiography and blood sampling at standardized time intervals. We measured the changes in global and regional LS before and after ICI administration. Age- and sex-adjusted Cox regression analysis was used to evaluate the association between LS and elevations in hsTnI and myocarditis.

Results

In a cohort of 129 patients with a median follow-up period of 170 (IQR: 62-365) days; 6 and 18 patients had myocarditis and hsTnI elevation, respectively. In an age- and sex-adjusted Cox proportional hazards model, an early relative worsening of ≥10% in the basal and mid LS and ≥15% in global LS was associated with hsTnI elevation. Relative reductions in LS were not significantly associated with myocarditis; however, 4 of the 6 patients with myocarditis had relative reduction of ≥10% in the basal LS.

Conclusions

An early worsening in the global and regional LS was associated with increased hsTnI in patients receiving ICIs. Assessment of LS early after ICI administration should be further studied as a strategy for risk stratification of ICI-treated patients.