Highly Sensitive Cardiac Troponins: The Evidence Behind Sex-Specific Cutoffs

High-Sensitivity Troponin: Finding a Meaningful Delta

High-sensitivity cardiac troponin (hs-cTn) assays have significantly refined the resolution of biomarker-level detection and have emerged as the gold standard cardiac biomarker in evaluating myocardial injury. Since its introduction, hs-cTn has been integrated into the Fourth Universal Definition of Myocardial Infarction and various European Society of Cardiology (ESC) and American College of Cardiology/American Heart Association (ACC/AHA) guidelines for the evaluation and diagnosis of chest pain syndromes. However, despite its integral role in caring for patients with chest pain, there are still substantive gaps in our knowledge of the clinical interpretation of dynamic changes in hs-cTn values. Whether a relative or absolute hs-cTn delta should be used to detect acute myocardial injury remains debatable. There are also emerging considerations of possible sex and racial/ethnic differences in clinically significant troponin deltas. In the emergency department, there is debate about the optimal time frame to recheck hs-cTn after symptom onset for myocardial infarction rule-out and whether hs-cTn deltas should be integrated into clinical risk scores. In this review, we will provide an overview of the history of clinical utilization of cardiac biomarkers, the development of hs-cTn assays, and the ongoing search for a meaningful delta that can be clinically applicable.

Association Between All-Cause Mortality and High-Sensitivity Cardiac Troponin Concentrations in Patients With Chest Pain

We assessed the association between troponin levels and all-cause mortality in individuals with chest pain who presented to the Charleston Area Medical Center Emergency Department (CAMC). We identified adult patients with chest pain as defined in the International Classification of Diseases 10 (R07) family group from the CAMC data warehouse between June 6, 2020, and June 6, 2021. These cases required a visit to the emergency room. We created 3 different cohorts to assess the endpoints of all-cause mortality at 30 days and 6 months. Patients were divided into the following 3 categories: negative troponin level, defined as high sensitivity troponin I (HSTNI) assay ≤15 pg/mL for women and ≤20 pg/mL for men; weakly positive, 21-88 pg/mL for men and 16-88 pg/mL for women; and strongly positive, >88 pg/mL for men and women. A propensity score matching analysis was also conducted using the negative group as a control; the weakly and strongly positive groups were compared to the control across differing cardiology covariates. This study introduces novel cutoffs for high-sensitivity troponin I (Beckman Coulter assay, Beckman Coulter, Inc., Chaska Campus, 1000 Lake Hazeltine Drive, Chaska, Minnesota 55318).

A guide to caring for patients who identify as transgender and gender diverse in the emergency department

Through a review of current research, standards of care, and best practices, this paper serves as a resource for emergency physicians (EPs) caring for persons who identify as transgender and gender diverse (T/GD) in the emergency department (ED). Both patient- and physician-based research have identified existent potential knowledge gaps for EPs caring for T/GD in the ED. T/GD have negative experiences related to their gender identity when seeking emergency medical care and may even delay emergency care for fear of discrimination. Through the lens of cultural humility, this paper aims to address potential knowledge gaps for EPs, identify and reduce barriers to care, highlight gender-affirming hospital policies and protocols, and improve the care and experience of T/GD in the ED.

Advances in research on biomarkers associated with acute myocardial infarction: A review

Acute myocardial infarction (AMI), the most severe cardiovascular event in clinical settings, imposes a significant burden with its annual increase in morbidity and mortality rates. However, it is noteworthy that mortality due to AMI in developed countries has experienced a decline, largely attributable to the advancements in medical interventions such as percutaneous coronary intervention. This trend highlights the importance of accurate diagnosis and effective treatment to preserve the myocardium at risk and improve patient outcomes. Conventional biomarkers such as myoglobin, creatine kinase isoenzymes, and troponin have been instrumental in the diagnosis of AMI. However, recent years have witnessed the emergence of new biomarkers demonstrating the potential to further enhance the accuracy of AMI diagnosis. This literature review focuses on the recent advancements in biomarker research in the context of AMI diagnosis.

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.

The Development of a Chest-Pain Protocol for Women Presenting to the Emergency Department

Cardiovascular disease (CVD) is the leading cause of death in women worldwide, and of premature death in women in Canada. Despite improvements in cardiovascular care over the past 15-20 years, acute coronary syndrome (ACS) and CVD mortality continue to increase among women in Canada. Chest pain is a common symptom leading to emergency department visits for both men and women. However, women with ACS experience worse outcomes. compared with those of men, due to misdiagnosis or lack of diagnosis resulting in delayed care and underuse of guideline-directed medical therapies. CVD mortality rates are highest in Indigenous and racialized women and those with a disproportionately high number of adverse social determinants of health. CVD remains underrecognized, underdiagnosed, undertreated, and underresearched in women. Moreover, a lack of awareness of unique symptoms, clinical presentations, and sex-and-gender specific CVD risk factors, by healthcare professionals, leads to outcome disparities. In response to this knowledge gap, in acute recognition and management of chest-pain syndromes in women, the Canadian Women's Heart Health Alliance performed a needs assessment and review of CVD risk factors and ACS pathophysiology, through a sex and gender lens, and then developed a unique chest-pain assessment protocol utilizing modified dynamic programming algorithmic methodology. The resulting algorithmic protocol is presented. The output is intended as a quick reference algorithm that could be posted in emergency departments and other acute-care settings. Next steps include protocol implementation evaluation and impact assessment on CVD outcomes in women.

Long term follow up and outcomes of Covid-19 vaccine associated myocarditis in Victoria, Australia: A clinical surveillance study

BACKGROUND

Myocarditis and myopericarditis are well described adverse events of special interest (AESI) following COVID-19 vaccinations. Although reports are reassuring regarding initial clinical outcomes, information about longer term outcomes remains limited. We aimed to further this knowledge and report outcomes to 6 months post diagnosis from a single population cohort.

METHODS

Reports of myocarditis following COVID-19 vaccination were followed up by SAEFVIC (Surveillance of Adverse Events Following Vaccination in the Community), the state-wide vaccine safety service for Victoria, Australia. Confirmed myocarditis cases (Brighton Collaboration Criteria levels 1-3) were followed up via surveys at 1, 3 and 6 months post symptom onset. Responses received between 22 February 2021 and 30 September 2022 were analysed.

RESULTS

87.5 % (N = 182) of eligible participants completed at least 1 survey report. 377 reports were analysed. 76.9 % of completed reports were from male patients. The median age of patients was 21 years [IQR: 16 to 32]. 54.8 % (n = 74) of survey reports at 6 months, reported ongoing symptoms. At all follow-up time points, females were significantly more likely to have ongoing symptoms. At 6 months, 51.9 % of male respondents reported symptom resolution compared to 22.6 % of female patients (p = 0.002). Females were also more likely to continue medication and have ongoing exercise restrictions. However, males were significantly more likely to have higher initial peak troponin results and abnormal initial cardiac imaging investigations.

CONCLUSIONS

There appears to be a significant proportion of patients who experience ongoing symptoms to 6 months post onset amongst patients that experience these AESI. Male patients were more likely to report earlier and more complete symptom recovery, despite significantly higher average initial peak troponin. This difference in phenotypic presentation in females compared to males warrants further investigation and there is a need for longer term follow up data.

Optimal Screening for Predicting and Preventing the Risk of Heart Failure Among Adults With Diabetes Without Atherosclerotic Cardiovascular Disease: A Pooled Cohort Analysis

BACKGROUND

The optimal approach to identify individuals with diabetes who are at a high risk for developing heart failure (HF) to inform implementation of preventive therapies is unknown, especially in those without atherosclerotic cardiovascular disease (ASCVD).

METHODS

Adults with diabetes and no HF at baseline from 7 community-based cohorts were included. Participants without ASCVD who were at high risk for developing HF were identified using 1-step screening strategies: risk score (WATCH-DM [Weight, Age, Hypertension, Creatinine, HDL-C, Diabetes Control, QRS Duration, MI, and CABG] ≥12), NT-proBNP (N-terminal pro-B-type natriuretic peptide ≥125 pg/mL), hs-cTn (high-sensitivity cardiac troponin T ≥14 ng/L; hs-cTnI ≥31 ng/L), and echocardiography-based diabetic cardiomyopathy (echo-DbCM; left atrial enlargement, left ventricular hypertrophy, or diastolic dysfunction). High-risk participants were also identified using 2-step screening strategies with a second test to identify residual risk among those deemed low risk by the first test: WATCH-DM/NT-proBNP, NT-proBNP/hs-cTn, NT-proBNP/echo-DbCM. Across screening strategies, the proportion of HF events identified, 5-year number needed to treat and number needed to screen to prevent 1 HF event with an SGLT2i (sodium-glucose cotransporter 2 inhibitor) among high-risk participants, and cost of screening were estimated.

RESULTS

The initial study cohort included 6293 participants (48.2% women), of whom 77.7% without prevalent ASCVD were evaluated with different HF screening strategies. At 5-year follow-up, 6.2% of participants without ASCVD developed incident HF. The 5-year number needed to treat to prevent 1 HF event with an SGLT2i among participants without ASCVD was 43 (95% CI, 29-72). In the cohort without ASCVD, high-risk participants identified using 1-step screening strategies had a low 5-year number needed to treat (22 for NT-proBNP to 37 for echo-DbCM). However, a substantial proportion of HF events occurred among participants identified as low risk using 1-step screening approaches (29% for echo-DbCM to 47% for hs-cTn). Two-step screening strategies captured most HF events (75-89%) in the high-risk subgroup with a comparable 5-year number needed to treat as the 1-step screening approaches (30-32). The 5-year number needed to screen to prevent 1 HF event was similar across 2-step screening strategies (45-61). However, the number of tests and associated costs were lowest for WATCH-DM/NT-proBNP ($1061) compared with other 2-step screening strategies (NT-proBNP/hs-cTn: $2894; NT-proBNP/echo-DbCM: $16 358).

CONCLUSIONS

Selective NT-proBNP testing based on the WATCH-DM score efficiently identified a high-risk primary prevention population with diabetes expected to derive marked absolute benefits from SGLT2i to prevent HF.

Sex-related differences in non-ischemic myocardial injury in the emergency department: A real-world perspective

BACKGROUND

Myocardial injury is associated with adverse outcomes. No data are reported about sex differences in incidence and factors associated with myocardial injury in an emergency department (ED) setting from a real-world perspective. We aimed to assess whether sex plays a major role in the diagnosis of myocardial injury in the ED.

METHODS

In this subanalysis of a retrospective study, patients presenting at the ED with at least one high-sensitivity cardiac troponin T (hs-cTnT) value and without acute coronary syndromes diagnosis were compared.

RESULTS

31,383 patients were admitted to the ED, 4660 had one hs-cTnT value, and 3937 were enrolled: 1943 females (49.4%) and 1994 males (50.6%). The diagnosis of myocardial injury was higher among men (36.8% vs. 32.9%, p < 0.01). Male sex was independently associated with myocardial injury. An older age, an elevated NT-proB-type Natriuretic Peptide and a lower estimated glomerular filtrate rate were independently associated with myocardial injury in both sexes.

CONCLUSIONS

In the ED, from a real-world perspective, myocardial injury occurred more frequently in males, and it was associated with older age and the presence of cardiac, lung, and kidney disease but not higher hs-cTnT values.

Impact of a high sensitivity troponin accelerated diagnostic protocol on the safety and emergency department length of stay of chest pain in an academic tertiary hospital: a quality improvement study

PURPOSE

High-sensitivity troponin (hsTn) accelerated diagnostic protocols are highly recommended for evaluating acute coronary syndromes. Our goal was to improve care for chest pain patients through the safe adoption of an accelerated diagnostic protocol in our academic Emergency Department (ED) with an aim to reduce mean ED length of stay for chest pain patients by 1 h over 1.5 years. Pre-accelerated diagnostic protocol, our mean ED length of stay for chest pain patients was 9.0 h.

METHODS

Using the Model for Improvement, we implemented a two-hour accelerated diagnostic protocol and conducted two Plan-Do-Study-Act cycles and education efforts to improve accelerated diagnostic protocol compliance and decrease ED length of stay. Using control charts, we measured the mean monthly ED length of stay for chest pain patients to look for special cause evidence of improvement. Process measures measured compliance with the accelerated diagnostic protocol. Balancing measures included the ED length of stay for abdominal pain patients and the number of admissions and deaths at 7 days for chest pain patients.

RESULTS

Mean ED length of stay for chest pain patients decreased from 9.0 to 8.2 h post-accelerated diagnostic protocol. The mean time between troponins decreased from 3.9 to 3.0 h, and the percentage of second troponins repeated at < 2.75 h increased from 22.3% to 58.6%. For abdominal pain patients, ED length of stay decreased from 10.8 to 10.5 h. No chest pain patients died within 7 days pre- or post-accelerated diagnostic protocol. Pre-accelerated diagnostic protocol, 0.84% (41/4,905) were admitted within 7 days. Post-accelerated diagnostic protocol and accelerated diagnostic protocol compliant, 0.70% (13/1,844) were admitted. Post-accelerated diagnostic protocol and accelerated diagnostic protocol non-compliant, 1.1% (13/1,183) were admitted.

CONCLUSION

We safely introduced a hsTn accelerated diagnostic protocol in an academic ED. ED length of stay decreased for chest pain patients but did not meet our 1-h goal.

Flexible-Interval High-Sensitivity Troponin Velocity for the Detection of Acute Coronary Syndromes

Many algorithms for emergency department (ED) evaluation of acute coronary syndrome (ACS) using high-sensitivity troponin assays rely on the detection of a "delta," the difference in concentration over a predetermined interval, but collecting specimens at specific times can be difficult in the ED. We evaluate the use of troponin "velocity," the rate of change of troponin concentration over a flexible short interval for the prediction of major adverse cardiac events (MACEs) at 30 days. We conducted a prospective, observational study on a convenience sample of 821 patients who underwent ACS evaluation at a high-volume, urban ED. We determined the diagnostic performance of a novel velocity-based algorithm and compared the performance of 1- and 2-hour algorithms adapted from the European Society of Cardiology (ESC) using delta versus velocity. A total of 7 of 332 patients (2.1%) classified as low risk by the velocity-based algorithm experienced a MACE by 30 days compared with 35 of 221 (13.8%) of patients classified as greater than low risk, yielding a sensitivity of 83.3% (95% confidence interval [CI] 68.6% to 93.0%) and negative predictive value (NPV) of 97.9% (95% CI 95.9% to 98.9%). The ESC-derived algorithms using delta or velocity had NPVs ranging from 98.4% (95% CI 96.4% to 99.3%) to 99.6% (95% CI 97.0% to 99.9%) for 30-day MACEs. The NPV of the novel velocity-based algorithm for MACE at 30 days was borderline, but the substitution of troponin velocity for delta in the framework of the ESC algorithms performed well. In conclusion, specimen collection within strict time intervals may not be necessary for rapid evaluation of ACS with high-sensitivity troponin.

Use of high-sensitivity cardiac troponin in the emergency department: A policy resource and education paper (PREP) from the American College of Emergency Physicians

This Policy Resource and Education Paper (PREP) from the American College of Emergency Physicians (ACEP) discusses the use of high-sensitivity cardiac troponin (hs-cTn) in the emergency department setting. This brief review discusses types of hs-cTn assays as well as the interpretation of hs-cTn in the setting of various clinical factors such as renal dysfunction, sex, and the important distinction between myocardial injury versus myocardial infarction. In addition, the PREP provides one possible example of an algorithm for the use of a hs-cTn assay in patients in whom the treating clinician is concerned about potential acute coronary syndrome.

Managing patients with sex-, race-, or ethnicity-based cardiovascular health inequities

ABSTRACT

Cardiovascular health inequities are experienced among cisgender women, gender minorities, Black and Indigenous people, and people with lower socioeconomic status. Early identification and treatment of patients at risk for disparate and adverse cardiac health outcomes are essential.

Lateral flow assays for detection of disease biomarkers

Early diagnosis saves lives in many diseases. In this sense, monitoring of biomarkers is crucial for the diagnosis of diseases. Lateral flow assays (LFAs) have attracted great attention among paper-based point-of-care testing (POCT) due to their low cost, user-friendliness, and time-saving advantages. Developments in the field of health have led to an increase of interest in these rapid tests. LFAs are used in the diagnosis and monitoring of many diseases, thanks to biomarkers that can be observed in body fluids. This review covers the recent advances dealing with the design and strategies for the development of LFA for the detection of biomarkers used in clinical applications in the last 5 years. We focus on various strategies such as choosing the nanoparticle type, single or multiple test approaches, and equipment for signal transducing for the detection of the most common biomarkers in different diseases such as cancer, cardiovascular, infectious, and others including Parkinson's and Alzheimer's diseases. We expect that this study will contribute to the different approaches in LFA and pave the way for other clinical applications.

Concentration of hs-Troponin in small cohort of transgender patients

INTRODUCTION

Sex-differences in high sensitivity troponin (hs-Tn) concentrations are well established. There is, however, limited data to guide interpretation of hs-Tn in transgender patients, particularly those receiving gender-affirming hormone therapy. Our purpose was to evaluate troponin testing in transgender patients.

METHODS

Transgender adults attending a routine clinic visit provided demographic data, medical history, and venous blood samples. Patients with congestive heart failure or chronic kidney disease were excluded. hs-Tn was measured using the Architect Stat High Sensitivity Troponin-I (Abbott), Access 2 hsTnI (Beckman Coulter), and Elecsys Troponin T Gen 5 STAT (Roche) assays. hs-Tn below the limit of detection (LOD) is reported as the lower limit of detection (LLOD) RESULTS: Of 63 subjects, 76 % were transgender women. We found no significant difference in median hs-Tn concentrations or proportions of hs-Tn > LOD.

CONCLUSION

In this cohort of stable transgender patients without CHF or CKD, we did not observe differences in hs-Tn concentrations between transgender women and transgender men. Meaningful conclusions are limited owing to inadequate sample size and population differences. Further research on hs-troponin concentrations in this underrepresented, vulnerable population is needed.

The Canadian Women's Heart Health Alliance Atlas on the Epidemiology, Diagnosis, and Management of Cardiovascular Disease in Women - Chapter 6: Sex- and Gender-Specific Diagnosis and Treatment

This chapter summarizes the sex- and gender-specific diagnosis and treatment of acute/unstable presentations and nacute/stable presentations of cardiovascular disease in women. Guidelines, scientific statements, systematic reviews/meta-analyses, and primary research studies related to diagnosis and treatment of coronary artery disease, cerebrovascular disease (stroke), valvular heart disease, and heart failure in women were reviewed. The evidence is summarized as a narrative, and when available, sex- and gender-specific practice and research recommendations are provided. Acute coronary syndrome presentations and emergency department delays are different in women than they are in men. Coronary angiography remains the gold-standard test for diagnosis of obstructive coronary artery disease. Other diagnostic imaging modalities for ischemic heart disease detection (eg, positron emission tomography, echocardiography, single-photon emission computed tomography, cardiovascular magnetic resonance, coronary computed tomography angiography) have been shown to be useful in women, with their selection dependent upon both the goal of the individualized assessment and the testing resources available. Noncontrast computed tomography and computed tomography angiography are used to diagnose stroke in women. Although sex-specific differences appear to exist in the efficacy of standard treatments for diverse presentations of acute coronary syndrome, many cardiovascular drugs and interventions tested in clinical trials were not powered to detect sex-specific differences, and knowledge gaps remain. Similarly, although knowledge is evolving about sex-specific difference in the management of valvular heart disease, and heart failure with both reduced and preserved ejection fraction, current guidelines are lacking in sex-specific recommendations, and more research is needed.

Ruling Out a Myocardial Infarction Safely in 30 Minutes: Implications for APRN Practice

This Research to Practice column assists to provide emergency advanced practice registered nurses an exploration of current evidence to establish implications for practice change within emergency care settings. The article, "Rapid Rule-Out of Myocardial Infarction After 30 Minutes as an Alternative to 1 Hour: The RACING-MI Cohort Study" by Bang et al. (2022), seeks to examine whether non-ST-segment elevation myocardial infarction identified on an electrocardiogram can be safely ruled out among a population of low-risk patients who present to the emergency department (ED) with undifferentiated acute chest pain. The study uses an accelerated 30-min testing algorithm of high-sensitivity troponin I markers as opposed to a traditional 1-hr high-sensitivity troponin I testing algorithm. The study results are presented to understand the factors of managing myocardial infarction (MI) and reducing patient length of stay surrounding MI care among ED providers at an emergency care center.

Relation of High-Sensitivity Cardiac Troponin I and Obstructive Coronary Artery Disease in Patients Without Acute Myocardial Infarction

The relation of high-sensitivity cardiac troponin I (hs-cTnI) concentration and presence of obstructive coronary artery disease (CAD) in patients without myocardial infarction (MI) is unclear. Study participants selected from patients free of MI who underwent coronary angiography with or without intervention were enrolled, and hs-cTnI measured. A gradient boosting model was implemented to build a model for detection of CAD. Cox proportional hazard regression was used to assess the association of hs-cTnI and adverse cardiovascular (CV) outcome. Among 978 study participants, 607 patients (62%) had CAD. Higher concentrations of hs-cTnI were associated with chronic kidney disease, heart failure, CAD, male gender, current tobacco use, anemia, age, and low-density lipoprotein cholesterol. History of CAD, male gender, type 2 diabetes mellitus, hs-cTnI, anemia, age, and high-density lipoprotein cholesterol were the most influential factors for detection of CAD. The gradient boosting model had an area under the curve of 0.82, accuracy of 75%, sensitivity of 88%, specificity of 52%, positive predictive value of 76%, and negative predictive value of 72% for detection of CAD. Increase in 1 log unit of hs-cTnI was significantly associated with increased risk of incident MI (hazard ratio [HR] 1.34, 95% confidence interval [CI] 1.22 to 1.47, p <0.001), CV mortality (HR 1. 24, 95% CI 1.11 to 1.39, p <0.001), and composite of incident MI or CV mortality (HR 1.29, 95% CI 1.20 to 1.40, p <0.001). In conclusion, among patients without acute MI and CAD, higher concentrations of hs-cTnI were associated with the presence of CAD and linked to increased risk of future CV events. ClinicalTrials.gov Identifier: NCT00842868.

Myocardial Injury, Troponin Release and Cardiomyocyte Death in Brief Ischemia, Failure and Ventricular Remodeling

Troponin released from irreversibly injured myocytes is the gold standard biomarker for the rapid identification of an acute coronary syndrome. In acute myocardial infarction, necrotic cell death is characterized by sarcolemmal disruption in response to a critical level of energy depletion after more than 15-minutes of ischemia. While troponin I and T are highly specific for cardiomyocyte death, high-sensitivity assays have demonstrated that measurable circulating levels of troponin are present in the majority of normal subjects. In addition, transient as well as chronic elevations have been demonstrated in many disease states not clearly associated with myocardial ischemia. The latter observations have given rise to the clinical concept of myocardial injury. This review will summarize evidence supporting the notion that circulating troponin levels parallel the extent of myocyte apoptosis in normal ventricular remodeling and in pathophysiological conditions not associated with infarction or necrosis. It will review the evidence that myocyte apoptosis can be accelerated by both diastolic strain from elevated ventricular preload as well as systolic strain from dyskinesis after brief episodes of ischemia too short to cause a critical level of myocyte energy depletion. We then show how chronic, low rates of myocyte apoptosis from endogenous myocyte turnover, repetitive ischemia or repetitive elevations in LV diastolic pressure can lead to significant myocyte loss in the absence of neurohormonal stimulation. Finally, we posit that the differential response to strain-induced injury in heart failure may determine whether progressive myocyte loss and HFrEF or interstitial fibrosis and HFpEF become the heart failure phenotype.

Contemporary Biomarker Strategies for Patients with Chest Pain

This review focuses on the strengths and limitations of conventional and high-sensitivity troponin in the evaluation of patients with suspected acute coronary syndromes. High-sensitivity troponin (hsTn) assays represent a significant innovation over prior generation troponin assays. Owing to superior analytical precision, hsTn permits more rapid "rule-in" and "rule-out" of myocardial infarction. Furthermore, hsTn assays, in properly implemented clinical pathways, permit a reduction in the portion of patients requiring extended observation and testing.

Features of the Metabolisms of Cardiac Troponin Molecules-Part 1: The Main Stages of Metabolism, Release Stage

Cardiac troponins (cTns) have long been the most valuable and specific biomarkers for detecting ischemic myocardial cells (MCs) injury, which is one of the key signs of myocardial infarction (MI). Modern methods (highly sensitive and ultra-sensitive immunoassays (hs-cTns)) of detection are an important and indispensable tool for the early diagnosis of MI and the choice of patient management protocols. Timely diagnosis of MI can significantly improve the prognosis of patients. However, in real clinical practice, doctors often face a significant problem when using cTns-the difficulty of differential diagnosis due to frequent and unexplained increases in the concentration of cTns in blood serum. In addition, there is conflicting information that may potentially affect the diagnostic capabilities and value of cTns: the influence of certain biological factors (diurnal rhythm, gender and age) on serum cTns levels; extra-cardiac expression of cTns; the possibilities of non-invasive diagnosis of MI; and other pathological conditions that cause non-ischemic injury to MCs. To solve these problems, it is necessary to concentrate on studying the metabolism of cTns. The review of our current knowledge about cTns metabolism consists of two parts. In this (first) part of the manuscript, the main stages of cTns metabolism are briefly described and the mechanisms of cTns release from MCs are considered in detail.

Sexual Dimorphism in Cardiovascular Biomarkers: Clinical and Research Implications

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

Triaging Down the 2021 Chest Pain Guidelines

We applied the 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR chest pain guidelines to a case of a 76-year-old woman with no known coronary disease presenting to the emergency department with acute chest pain and an intermediate probability of acute coronary syndrome. Her workup per the guidelines involved rapid electrocardiogram, high-sensitivity troponins, nuclear stress testing, and eventually coronary invasive angiography. (Level of Difficulty: Advanced.)

Beta blocker use in traumatic brain injury based on the high-sensitive troponin status (BBTBBT): methodology and protocol implementation of a double-blind randomized controlled clinical trial

Background

Beta-adrenergic receptor blockers (BB) play an important role in the protection of organs that are susceptible for secondary injury due to stress-induced adrenergic surge. However, the use of BB in traumatic brain injury (TBI) patients is not yet the standard of care which necessitates clear scientific evidence to be used. The BBTBBT study aims to determine whether early administration of propranolol based on the high-sensitive troponin T(HsTnT) status will improve the outcome of TBI patients. We hypothesized that early propranolol use is effective in reducing 10- and 30-day mortality in TBI patients. Secondary outcomes will include correlation between serum biomarkers (troponin, epinephrine, cytokines, enolase, S100 calcium binding protein B) and the severity of injury and the impact of BB use on the duration of hospital stay and functional status at a 3-month period.

Methods

The BBTBBT study is a prospective, randomized, double-blinded, placebo-controlled three-arm trial of BB use in mild-to-severe TBI patients based on the HsTnT status. All enrolled patients will be tested for HsTnT at the first 4 and 6 h post-injury. Patients with positive HsTnT will receive BB if there is no contraindication (group 1). Patients with negative HsTnT will be randomized to receive either propranolol (group 2) or placebo (group 3). The time widow for receiving the study treatment is the first 24 h post-injury.

Discussion

Early BB use may reduce the catecholamine storm and subsequently the cascade of immune and inflammatory changes associated with TBI. HsTnT could be a useful fast diagnostic and prognostic tool in TBI patients. This study will be of great clinical interest to improve survival and functional outcomes of TBI patients.

Trial registration

ClinicalTrials.gov NCT04508244. Registered on 7 August 2020. Recruitment started on 29 December 2020 and is ongoing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05872-8.

Syndrome of Nonobstructive Coronary Artery Diseases: A Comprehensive Overview of Open Artery Ischemia

Syndromes of cardiac ischemia with nonobstructive coronary arteries have been increasingly recognized as a clinical entity with heterogeneous clinical presentations, commonly encountered in women. Knowledge of pathophysiology and clinical risk factors is key to ensuring appropriate diagnostic evaluation and management for these often-neglected patients. In this review, we discuss the epidemiology, risk factors, and clinical presentations of these syndromes. We provide algorithms for diagnosis and management of these entities based on current scientific knowledge and highlight some of the key knowledge gaps and ongoing trials in this emerging field.

Cardiac Troponins Metabolism: From Biochemical Mechanisms to Clinical Practice (Literature Review)

The metabolic processes of endo- and exogenous compounds play an important role in diagnosing and treating patients since many metabolites are laboratory biomarkers and/or targets for therapeutic agents. Cardiac troponins are one of the most critical biomarkers to diagnose cardiovascular diseases, including acute myocardial infarction. The study of troponin metabolism is of great interest as it opens up new possibilities for optimizing laboratory diagnostics. This article discusses in detail the key stages of the cardiac troponins metabolism, in particular the mechanisms of release from a healthy myocardium, mechanisms of circulation in the bloodstream, possible mechanisms of troponin penetration into other biological fluids (oral fluid, cerebrospinal fluid, pericardial and amniotic fluids), mechanisms of elimination of cardiac troponins from the blood, and daily changes in the levels of troponins in the blood. Considering these aspects of cardiac troponin metabolism, attention is focused on the potential value for clinical practice.

Correlates of Delayed Initial Contact to Emergency Services among Patients with Suspected ST-Elevation Myocardial Infarction

Background

Early diagnosis and treatment of a patient displaying symptoms of myocardial ischemia is paramount in preventing detrimental tissue damage, arrhythmias, and death. Patient-related hospital delay is the greatest considerable cause of total delay in treatment for acute myocardial infarction.

Objective

To identify patient characteristics contributing to prehospital delay and ultimately developing health interventions to prevent future delay and improve health outcomes.

Methods

A retrospective chart review of 287 patients diagnosed with ST-elevation myocardial infarction (STEMI) was evaluated to examine correlates of patient-related delays to care.

Results

Stepwise logistic regression modeling with forward selection (likelihood ratio) was performed to identify predictors of first medical contact (FMC) within 120 minutes of symptom onset and door-to-balloon (DTB) time within 90 minutes. Distance from the hospital, being unmarried, self-medicating, disability, and hemodynamic stability emerged as variables that were found to be predictive of FMC within the first 120 minutes after symptom onset. Similarly, patient characteristics of gender and disability and having an initial nondiagnostic electrocardiogram emerged as significant predictors of DTB within 90 minutes.

Conclusions

Individual attention to high-risk patients and public education campaigns using printed materials, public lectures, and entertainment mediums are likely needed to disseminate information to improve prevention strategies. Future research should focus on identifying the strengths of prehospital predictors and finding other variables that can be established as forecasters of delay. Interventions to enhance survival in acute STEMI should continue as to provide substantial advances in overall health outcomes.

Cardiac troponin I and the risk of cardiovascular or non-cardiovascular death in patients visiting the emergency department

The prognostic implication of cardiac troponin I (cTnI) values for the determination of the magnitude or duration of cause-specific death risk is limited. We included consecutive patients with maximal cTnI values within 24 h of their emergency department visits. Multivariate analyses using variables selected by the Bayesian information criterion were performed to investigate the impact of cTnI on the event rate, time-dependent risk, and dose-dependent risk of cardiovascular or non-cardiovascular death within 360 days. There were 5472 (14.9%) all-cause deaths including 881 (2.4%) cardiovascular deaths and 4591 (12.5%) non-cardiovascular deaths. In patients with positive cTnI, defined as the ≥ 99th percentile of the upper normal limit, the cumulative risk of cardiac and non-cardiac death was 4.4- and 1.4-fold higher, respectively, than that of negative cTnI, respectively. In the competing risk analysis, positive cTnI was linked to 2.4- and 1.2-fold higher risks of cardiovascular and non-cardiovascular death, respectively. The cTnI value showed a positive relationship with the risk of both cardiovascular and non-cardiovascular deaths. In the time-dependent risk analysis, the excess risk of cardiovascular death was mostly evident in the first few weeks. Higher cTnI value was associated with an increased risk of both cardiovascular and non-cardiovascular death, especially which was in the early period.

Do age-adjusted sex-specific cut-off values improve the agreement between high sensitivity cardiac troponins I and T? A retrospective study

BACKGROUND

Many reports noted a disagreement between High sensitivity cardiac Troponin (hs-cTn) assays on the diagnosis of Acute Coronary Syndrome (ACS).

METHODS

We conducted a retrospective study aiming to assess the agreement between hs-cTn T (Roche) and hs-cTn I (Abbott) in patients presenting with a suspected ACS to the emergency department at Hotel-Dieu hospital between September 2017 and October 2019 using overall, sex-specific, and age-adjusted sex-specific cut-off values. This was measured using Cohen's Kappa. We explored whether renal function, circadian rhythm, age and sex influenced the discordance. And we analyzed the trend of agreement between baseline and repeated measurements.

RESULTS

4856 patients who had simultaneous hs-cTn I and T values were retained for the analysis. 53.5% had a hs-cTn T above the overall 99th percentile, compared to 19.9% for hs-cTn I. The numbers were significantly reduced when applying age-adjusted sex-specific 99th percentile. A disagreement was seen in 34% of cases using overall 99th percentile. Using sex-specific cut off values did not impact this discordance; however, age-adjusted sex-specific cut-off values reduced the percentage of discrepancies to 15.8%. The decreased renal function had a negative effect on the agreement while the circadian rhythm had minimal effect. This initial discordance was carried forward into repeated measurements.

CONCLUSION

The disagreement between hs-cTn T and I assays could be imputed to the choice of cut-off values. The use of age-adjusted sex specific 99th percentile reduced majorly these discordances. Further studies are needed in order to evaluate their clinical utility in patients presenting with ACS.

Advancements in biomarkers for cardiovascular disease: diagnosis, prognosis, and therapy

Biomarkers are essential tools in the practice of cardiology. They assist with diagnosis, prognosis, and guiding therapy in many different cardiovascular diseases. Numerous biomarkers have become strongly associated with different cardiovascular conditions, such as troponin with acute coronary syndrome and natriuretic peptides with heart failure. Even though these biomarkers have been in practice for almost two decades, their uses continue to expand beyond their original roles. Additionally, many new biomarkers have been discovered with increasing utility in cardiovascular disease, including soluble suppression of tumorigenicity 2, galectin 3, and biomarkers of fibrosis, metabolism, and inflammation. How these old and new biomarkers are being expanded into clinical practice is constantly in evolution. This review will highlight some of the recent major advancements in the rapidly evolving field of biomarkers.

Performance of ivisen IA-1400, a new point-of-care device with an internal centrifuge system, for the measurement of cardiac troponin I levels

BACKGROUND

We present the analytical performance of the ivisen IA-1400, a new point-of-care device that features a characteristic built-in centrifuge system, to measure blood cardiac troponin I (cTnI) levels.

METHODS

Whole blood and plasma samples obtained from patients who visited Korea University Guro Hospital were used to analyze measurement range, cross-reactivity, interference, and sensitivity and specificity. We performed a correlation analysis of the ivisen IA-1400 versus the Access AccuTnI+3 immunoassay using the UniCel™ DxI 800 platform and the PATHFAST™ hs-cTnI assay.

RESULTS

Within-run precisions were classified as low, 9.8%; middle, 10.2%; and high, 8.5%. The limit of blank was 3.1 ng/L for plasma samples and 4.3 ng/L for whole blood samples. The limit of detection was 8.4 ng/L for plasma samples and 10.0 ng/L for whole blood samples, respectively. The limit of quantitation at a coefficient of variation of 20% and 10% was 19.5 ng/L and 45.5 ng/L for plasma samples, respectively. The comparative evaluation between the two other assays and ivisen IA-1400 showed excellent correlation, with Spearman's correlation coefficients (R) of 0.992 and 0.985. The sensitivity and specificity of ivisen IA-1400 using the optimum cut-off value of 235 ug/L were 94.6% and 98.2%, respectively.

CONCLUSION

The ivisen IA-1400 showed acceptable and promising performance in cTnI measurements using whole blood and plasma samples, with limited information in the clinical performance. The flexibility for sample selection using the internal centrifugation system is the main advantage of this point-of-care device.

Highly Sensitive Cardiac Troponins: The Evidence Behind Sex-Specific Cutoffs

Emergence of various highly sensitive cardiac troponin assays into clinical practice provides a new tool for clinicians diagnosing acute coronary syndrome. These assays also create a challenge for laboratories and clinicians who have yet to familiarize themselves with sex-specific cutoffs. Healthy men and women, studied across various age groups and geographic locations, have notable differences in baseline values of highly sensitive cardiac troponin I and T, leading to establishment of sex-specific upper reference limits and cutoffs. Several differences in cardiac physiology, size, and structure may account for baseline differences in highly sensitive cardiac troponins and outcomes between the sexes. The clinical utility of implementing sex-specific cutoffs for diagnosis and management of acute coronary syndrome remains unclear. Presently, the only prospective study failed to show improved outcomes for men or women with use of sex-specific cutoffs; however, a major limitation is the frequent lack of diagnostic, therapeutic, and preventive interventions prescribed to women with low-level troponin elevations. Based on the current literature, we posit that there may nonetheless be clinical value in the use of sex-specific cutoffs for evaluating suspected acute coronary syndrome, especially in select patient populations such as younger women who tend to have lower baseline values of highly sensitive cardiac troponins. Future studies should prospectively evaluate differences in diagnostic, pharmacologic, and interventional management in men and women using myocardial infarctions classified with sex-specific cutoffs of the highly sensitive cardiac troponin assays.