Sensitive troponin I assay in early diagnosis of acute myocardial infarction

Clinical and Analytical Performance of a Novel Point-of-Care High-Sensitivity Cardiac Troponin I Assay

BACKGROUND

Point-of-care (POC) high-sensitivity cardiac troponin assays may further accelerate the diagnosis of myocardial infarction (MI).

OBJECTIVES

This study sought to assess the clinical and analytical performance of the novel high-sensitivity cardiac troponin I (hs-cTnI)-SPINCHIP POC test.

METHODS

Adult patients presenting with acute chest discomfort to the emergency department were enrolled in an international, diagnostic, multicenter study. The final diagnosis was centrally adjudicated by 2 independent cardiologists using all clinical information. We compared the discriminatory performance of hs-cTnI-SPINCHIP with current established central laboratory assays and derived an assay-specific hs-cTnI-SPINCHIP 0/1-hour algorithm. Secondary analyses included sample type comparisons (whole blood, fresh/frozen plasma, and capillary finger prick) and precision analysis.

RESULTS

MI was the adjudicated final diagnosis in 214 (19%) of 1,102 patients. Area under the receiver-operating characteristic curve was 0.94 (95% CI: 0.92-0.95) for hs-cTnI-SPINCHIP vs 0.94 (95% CI: 0.92-0.95) for hs-cTnI-Architect (P = 0.907) and 0.93 (95% CI: 0.91-0.95) for high-sensitivity cardiac troponin T Elecsys (P = 0.305). A cutoff <7 ng/L at presentation (if chest pain onset was >3 hours) or <7 ng/L together with a 0/1-hour delta of <4 ng/L ruled out 51% with a sensitivity and negative predictive value of 100% (95% CI: 97.7%-100%) and 100% (95% CI: 99.0%-100%), respectively. A hs-cTnI-SPINCHIP concentration ≥36 ng/L or a 0/1-hour delta ≥11 ng/L ruled in 27% with a specificity and positive predictive value of 90.9% (95% CI: 88.3%-92.9%) and 72.9% (95% CI: 66.4%-78.6%), respectively. Bootstrap internal validation confirmed excellent diagnostic performance. High agreement was observed between different sample types.

CONCLUSIONS

The SPINCHIP hs-cTnI POC test has very high diagnostic accuracy. Its assay-specific 0/1-hour algorithm achieved very high sensitivity/negative predictive value and specificity/positive predictive value for rule-out/in MI. (Advantageous Predictors of Acute Coronary Syndromes Evaluation [APACE] Study [APACE]; NCT00470587).

The current paradigm of cardiac troponin increase among athletes

Although it is known that exercise improves cardiovascular health and extends life expectancy, a significant number of people may also experience an elevation in cardiac troponin levels as a result of exercise. For many years, researchers have argued whether exercise-induced cardiac troponin rises are a consequence of a physiological or pathological reaction and whether they are clinically significant. Differences in cardiac troponin elevation and cardiac remodeling can be seen between athletes participating in different types of sports. When forecasting the exercise-induced cardiac troponin rise, there are many additional parameters to consider, as there is a large amount of interindividual heterogeneity in the degree of cardiac troponin elevation. Although it was previously believed that cardiac troponin increases in athletes represented a benign phenomenon, numerous recent studies disproved this notion by demonstrating that, in specific individuals, cardiac troponin increases may have clinical and prognostic repercussions. This review aims to examine the role of cardiac troponin in athletes and its role in various sporting contexts. This review also discusses potential prognostic and clinical implications, as well as future research methods, and provides a straightforward step-by-step algorithm to help clinicians interpret cardiac troponin rise in athletes in both ischemic and non-ischemic circumstances.

E, Jones J, Li J. Evaluation of Age and Sex Differences in Contemporary versus High-Sensitivity Troponin I Measurement in Hospitalized Patients

Background: With the transition from the contemporary (cTnI) to high-sensitivity troponin assay (hs-cTnI), concerns have arisen regarding the diagnostic differences between these two assays due to analytical distinctions. This study aims to evaluate the age and sex differences between these two assays, as well as the differences resulting from using two different 99th percentile values of the high-sensitivity troponin assay. Method: A retrospective observational study was conducted at an academic medical center, encompassing a total of 449 lithium heparin plasma samples included in the dataset. Both contemporary and high-sensitivity troponin were simultaneously measured using Siemens ADVIA Centaur analyzers. Two sets of sex-specific 99th percentile URLs from the Siemens study (cutoff-1) and Universal Sample Bank data (cutoff-2) were used for the data analysis. Results: The use of cutoff-1 or cutoff-2 had a negligible impact on troponin classification. Troponin elevation significantly increased in individuals > 50 years old for males and >40 years old for females, with both troponin assays. A receiver operating characteristic analysis did not find significant differences between the two assays. The Kaplan-Meier curves showed no differences in survival in cTnI according to the non-sex-specific 99th URL or hs-cTnI (cutoff-2) but showed a slight difference in survival in hs-cTnI (cutoff-1). Conclusions: Overall, there were no significant differences in age and sex in the diagnostic performance between the contemporary and high-sensitivity troponin assays. Selection criteria for the establishment of the 99th percentile URL should be standardized to avoid the misinterpretation of the troponin results.

Age-Related Patterns of Symptoms and Risk Factors in Acute Coronary Syndrome (ACS): A Study Based on Cardiology Patients' Records at Rehman Medical Institute, Peshawar

Introduction Acute Coronary Syndrome (ACS) is a critical condition characterized by reduced blood flow to the heart and includes various conditions such as ST-elevation myocardial infarction, non-ST elevation myocardial infarction, and unstable angina. Objectives The aim of this study was to investigate age-related patterns of symptoms and risk factors in ACS patients and to evaluate how diagnostic test results differ among various age groups of ACS patients. Methodology This retrospective study was conducted from May to November of 2023 on patients with acute coronary syndrome admitted to the cardiology ward of Rehman Medical Institute (RMI), Peshawar. The sample size was 137 ACS-diagnosed patients based on the inclusion and exclusion criteria. After getting ethical approval from the institutional ethical approval board, data were collected for the entire year of 2022 based on proforma with the variables demographic data, troponin I level, presented symptoms, and associated co-morbidities of the patients. The inclusion criteria were patients of all genders, patients diagnosed with Acute Coronary Syndrome (ACS), and patients whose records were available in the cardiology department of Rehman Medical Institute.  Results The results show that ACS is more prevalent in the age group of 50-69 years (p=0.037) and is significantly more common in males (p=0.019). Chest pain emerged as the predominant symptom, with a significant association of p=0.029 between chest pain and patients of ACS in the age group 30-49 years. While raised troponin I levels were prevalent across all age groups. Moreover, specific risk factors such as diabetes mellitus, hypertension, and family history of CAD showed the significance of p= 0.04, p=0.006, and p=0.021, respectively, with the age group 50-69 years old. Conclusion This study highlights the importance of considering age and gender in ACS management and provides insights into age-related patterns of symptoms and risk factors, which can contribute to optimizing preventive strategies and improving patient care. Further research is needed to explore the underlying mechanisms and assess long-term outcomes in different age groups.

Aptamer-Antibody Chimera Sensors for Sensitive, Rapid, and Reversible Molecular Detection in Complex Samples

The development of receptors suitable for the continuous detection of analytes in complex, interferent-rich samples remains challenging. Antibodies are highly sensitive but difficult to engineer in order to introduce signaling functionality, while aptamer switches are easy to construct but often yield only a modest target sensitivity. We present here a programmable antibody and DNA aptamer switch (PANDAS), which combines the desirable properties of both receptors by using a nucleic acid tether to link an analyte-specific antibody to an internal strand-displacement (ISD)-based aptamer switch that recognizes the same target through different epitopes. The antibody increases PANDAS analyte binding due to its high affinity, and the effective concentration between the two receptors further enhances two-epitope binding and fluorescent aptamer signaling. We developed a PANDAS sensor for the clotting protein thrombin and show that a tuned design achieves a greater than 300-fold enhanced sensitivity compared to that of using an aptamer alone. This design also exhibits reversible binding, enabling repeated measurements with a temporal resolution of ∼10 min, and retains excellent sensitivity even in interferent-rich samples. With future development, this PANDAS approach could enable the adaptation of existing protein-binding aptamers with modest affinity to sensors that deliver excellent sensitivity and minute-scale resolution in minimally prepared biological specimens.

Subclinical myocardial damage after anthracycline chemotherapy in Japanese patients with breast cancer

BACKGROUND

Data on the incidence, timing, and severity of myocardial damage after anthracycline-based chemotherapy (AC) in Japanese patients with breast cancer are limited.

METHOD

We evaluated cancer therapy-related cardiac dysfunction (CTRCD) in Japanese women with breast cancer (n = 51) after the first AC according to the definitions of the 2022 European Society of Cardiology onco-cardiology guideline, including assessment of high-sensitivity troponin I (TnI) and B-type natriuretic peptide (BNP) levels.

RESULTS

CTRCD was detected in 67 % of the patients (3.9 %, 7.8 %, 9.8 %, 43 %, 37 %, 22 %, 20 %, and 9.8 % of patients at 1 week and 1, 2, 3, 6, 9, 12, and 15 months post-AC, respectively) without significant left ventricular ejection fraction reduction (<50 %) and heart failure. Elevated TnI levels (>26 pg/mL) were found in 43 % of patients, and elevated BNP levels (≥35 pg/mL) were observed in 22 % of patients during the follow-up period.

CONCLUSIONS

Approximately two-thirds of the Japanese patients in this study experienced CTRCD, which was frequently observed at 3 or 6 months post-AC. However, all patients with CTRCD were diagnosed with mild asymptomatic CTRCD. Although, these patients were diagnosed with mild asymptomatic CTRCD, careful long-term follow-up will be required.

The Role of Artificial Intelligence for Providing Scientific Content for Laboratory Medicine

BACKGROUND

Artificial intelligence (AI) promises to become an important tool in the practice of laboratory medicine. AI programs are available online that can provide concise medical and laboratory information within seconds after a question is submitted.

METHODS

We posed the following contemporary and relevant question for clinical chemists using an AI program: "Should labs eliminate CK-MB testing?" The results of this inquiry were critically reviewed by a cardiologist, emergency department physician, and clinical laboratorians for accuracy and appropriateness.

RESULTS

An AI report answering this question was generated within 15 s. The experts felt that the information was inaccurate with the statements that CK-MB results are released earlier than cardiac troponin (cTn), and are more useful for detection of myocardial injury in patients with renal insufficiencies. The summary omitted discussion on the ongoing debate for periprocedural detection of acute myocardial infarction (MI), the perceived value for detection of reinfarction, the value in risk stratification compared to cTn, the economic justification for testing both CK-MB and cTn, and medicolegal aspects of testing when results are discordant.

CONCLUSIONS

At this time, AI does not appear to be ready to be used by clinical laboratories for answering important practice questions.

Unraveling the Signaling Dynamics of Small Extracellular Vesicles in Cardiac Diseases

Effective intercellular communication is essential for cellular and tissue balance maintenance and response to challenges. Cellular communication methods involve direct cell contact or the release of biological molecules to cover short and long distances. However, a recent discovery in this communication network is the involvement of extracellular vesicles that host biological contents such as proteins, nucleic acids, and lipids, influencing neighboring cells. These extracellular vesicles are found in body fluids; thus, they are considered as potential disease biomarkers. Cardiovascular diseases are significant contributors to global morbidity and mortality, encompassing conditions such as ischemic heart disease, cardiomyopathies, electrical heart diseases, and heart failure. Recent studies reveal the release of extracellular vesicles by cardiovascular cells, influencing normal cardiac function and structure. However, under pathological conditions, extracellular vesicles composition changes, contributing to the development of cardiovascular diseases. Investigating the loading of molecular cargo in these extracellular vesicles is essential for understanding their role in disease development. This review consolidates the latest insights into the role of extracellular vesicles in diagnosis and prognosis of cardiovascular diseases, exploring the potential applications of extracellular vesicles in personalized therapies, shedding light on the evolving landscape of cardiovascular medicine.

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.

Aiming toWards Evidence baSed inTerpretation of Cardiac biOmarkers in patients pResenting with chest pain using Point of Care Testing (WESTCOR-POC): study design

OBJECTIVES

Patients presenting with symptoms suggestive of acute coronary syndrome (ACS) contribute to a high workload and overcrowding in the Emergency Department (ED). Accelerated diagnostic protocols for non-ST-elevation myocardial infarction have proved challenging to implement. One obstacle is the turnaround time for analyzing high-sensitivity cardiac troponin (hs-cTn). In the WESTCOR-POC study (Clinical Trials number NCT05354804) we aim to evaluate safety and efficiency of a 0/1 h hs-cTn algorithm utilizing a hs-cTnI point of care (POC) instrument in comparison to central laboratory hs-cTnT measurements.

DESIGN

This is a prospective single-center randomized clinical trial aiming to include 1500 patients admitted to the ED with symptoms suggestive of ACS. Patients will receive standard investigations following the European Society of Cardiology 0/1h protocols for centralized hs-cTnT measurements or the intervention using a 0/1h POC hs-cTnI algorithm. Primary end-points are 1) Safety; death, myocardial infarction or acute revascularization within 30 days 2) Efficiency; length of stay in the ED, 3) Cost- effectiveness; total episode cost, 4) Patient satisfaction, 5) Patient symptom burden and 6) Patients quality of life. Secondary outcomes are 12-months death, myocardial infarction or acute revascularization, percentage discharged after 3 and 6 h, total length of hospital stay and all costs related to hospital contact within 12 months.

CONCLUSION

Results from this study may facilitate implementation of POC hs-cTn testing assays and accelerated diagnostic protocols in EDs, and may serve as a valuable resource for guiding future investigations for the use of POC high sensitivity troponin assays in outpatient clinics and prehospital settings.

Association between troponin level and medium-term mortality in 20 000 hospital patients

INTRODUCTION

Cardiac troponin (cTn) concentrations above the manufacturer recommended upper limit of normal (ULN) are frequently seen in hospital patients without a clinical presentation consistent with type 1 myocardial infarction, and the significance of this is uncertain. The aim of this study was to assess the relationship between medium-term mortality and cTn concentration in a large consecutive hospital population, regardless of whether there was a clinical indication for performing the test.

METHOD

This prospective observational study included 20 000 consecutive in-hospital and outpatient patients who had a blood test for any reason at a large teaching hospital, and in whom a hs-cTnI assay was measured, regardless of the original clinical indication. Mortality was obtained via NHS Digital.

RESULTS

A total of 20 000 patients were included in the analysis and 18 282 of these (91.4%) did not have a clinical indication for cardiac troponin I (cTnI) testing. Overall, 2825 (14.1%) patients died at a median of 809 days. The mortality was significantly higher if the cTnI concentration was above the ULN (45.3% vs 12.3% p<0.001 log rank). Multivariable Cox analysis demonstrated that the log10 cTnI concentration was independently associated with mortality (HR 1.76 (95% CI 1.65 to 1.88)). Landmark analysis, excluding deaths within 30 days, showed the relationship between cTnI concentration and mortality persisted.

CONCLUSION

In a large, unselected hospital population, in 91.4% of whom there was no clinical indication for testing, cTnI concentration was independently associated with medium-term cardiovascular and non-cardiovascular mortality in the statistical model tested.

Comparing the utility of clinical risk scores and integrated clinical judgement in patients with suspected acute coronary syndrome

AIMS

The utility of clinical risk scores regarding the prediction of major adverse cardiac events (MACE) is uncertain. We aimed to directly compare the prognostic performance of five established clinical risk scores as well as an unstructured integrated clinical judgement (ICJ) of the treating emergency department (ED) physician.

METHODS AND RESULTS

Thirty-day MACE including all-cause death, life-threatening arrhythmia, cardiogenic shock, acute myocardial infarction (including the index event), and unstable angina requiring urgent coronary revascularization were centrally adjudicated by two independent cardiologists in patients presenting to the ED with acute chest discomfort in an international multicentre study. We compared the prognostic performance of the HEART score, GRACE score, T-MACS, TIMI score, and EDACS, as well as the unstructured ICJ of the treating ED physician (visual analogue scale to estimate the probability of acute coronary syndrome, ranging from 0 to 100). Among 4551 eligible patients, 1110/4551 patients (24.4%) had at least one MACE within 30 days. Prognostic accuracy was high and comparable for the HEART score, GRACE score, T-MACS, and ICJ [area under the receiver operating characteristic curve (AUC) 0.85-0.87] but significantly lower and only moderate for the TIMI score (AUC 0.79, P < 0.001) and EDACS (AUC 0.74, P < 0.001), resulting in sensitivities for the rule-out of 30-day MACE of 93-96, 87 (P < 0.001), and 72% (P < 0.001), respectively.

CONCLUSION

The HEART score, GRACE score, T-MACS, and unstructured ICJ of the treating physician, not the TIMI score or EDACS, performed well for the prediction of 30-day MACE and may be considered for routine clinical use.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT00470587.

Is COPD the Determinant Factor for Myocardial Injury and Cardiac Wall Stress in OSA Patients?

Background and Objectives: Evidence shows that COPD-OSA overlap syndrome (OS) is more frequently accompanied by cardiovascular disease (CVD) in comparison to either disease alone. The aim of the study was to explore whether patients with OS have a higher burden of subclinical myocardial injury and wall stress compared with OSA patients. Materials and Methods: Consecutive patients, without established CVD, underwent polysomnography and pulmonary function testing, due to suspected sleep-disordered breathing. An equal number of patients with OS (n = 53, with an apnea hypopnea index (AHI) > 5/h and FEV1/FVC < 0.7) and patients with OSA (n = 53, AHI > 5/h and FEV1/FVC > 0.7) were included in the study. The detection of asymptomatic myocardial injury and wall stress was performed via the assessment of serum high-sensitivity cardiac troponin T (hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), respectively. Results: OS patients were older (p < 0.001) and had worse hypoxemic parameters, namely average oxyhemoglobin saturation (SpO2) (p = 0.002) and time spent with SpO2 < 90% (p = 0.003) during sleep as well as daytime pO2 (p < 0.001), than patients with OSA. No difference was observed between groups in terms of Epworth Sleepiness Scale (p = 0.432) and AHI (p = 0.587). Both levels of hs-cTnT (14.2 (9.1-20.2) vs. 6.5 (5.6-8.7) pg/mL, p < 0.001) and NT-proBNP (93.1 (37.9-182.5) vs. 19.2 (8.3-35.4) pg/mL, p < 0.001) were increased in OS compared to OSA patients. Upon multivariate linear regression analysis, levels of NT-proBNP and hs-cTnT correlated with age and average SpO2 during sleep. Conclusions: Our study demonstrated higher levels of hs-cTnT and NT-proBNP in OS patients, indicating an increased probability of subclinical myocardial injury and wall stress, compared with OSA individuals.

Multicenter analysis to assess risk of major adverse cardiac events in patients undergoing high-sensitivity troponin testing in the emergency department

Study hypothesis

Our objective was to evaluate 30-day major adverse cardiac events (MACE) in emergency department (ED) patients with normal high-sensitivity troponins (hs-trop). We hypothesized that MACE rates would be <1% in patients with (1) two normal troponins regardless of change in troponin (delta) and (2) index hs-trop below the limit of quantitation (LOQ) regardless of the institution modified HEART score.

Methods

This was a multicenter, retrospective, cohort study of adult patients who presented to 1 of 18 EDs between July 2020 and April 2021 with acute coronary syndrome as defined by an institutional-modified HEART score completed by their treating physician or midlevel, no evidence of ST-elevation myocardial infarction, and an index or serial gender-adjusted hs-trop within normal limits. The primary outcome was MACE within 30 days of index ED encounter. A detailed case review was then performed for those patients experiencing a MACE.

Results

Of the 9084 patients who had single or serial normal troponins, 31 (0.34%; confidence interval [CI] 0.23%-0.48%) experienced MACE. Of the 6140 patients with 2 normal hs-trop and a delta (change in troponin) <4, 27 patients (0.44%; CI 0.29%-0.64%) experienced MACE. Only 1 of the 69 patients with 2 normal hs-trop results but delta (change in troponin) ≥ 4 (1.45%; CI 0.04%-7.81%) suffered MACE. This patient was classified as non-low risk by our institutional HEART score. Of 7498 patients with an index hs-trop 

Conclusion

Patients with 2 normal hs-trop values in the ED are unlikely to suffer 30-day MACE. Although it remains unclear whether patients with delta (change in troponin) ≥4 despite normal troponins will have a 30-day MACE, this situation is rare. Additionally, a single index hs-trop <6 ng/L demonstrated a low risk for 30-day MACE independent of the institutional HEART score.

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Affiliation(s)

Victoria Serven Department of Emergency MedicineAtrium Health's Carolinas Medical CenterCharlotteNorth CarolinaUSA
Kamala Swayampakala Sanger Heart & Vascular InstituteAtrium HealthCharlotteNorth CarolinaUSA
Christy Lesassier Sanger Heart & Vascular InstituteAtrium HealthCharlotteNorth CarolinaUSA
Tyler Siekmann Department of Emergency MedicineAtrium Health's Carolinas Medical CenterCharlotteNorth CarolinaUSA
Gabriel Rivera‐Camacho Department of Emergency MedicineAtrium Health's Carolinas Medical CenterCharlotteNorth CarolinaUSA
Santosh Rao Sanger Heart & Vascular InstituteAtrium HealthCharlotteNorth CarolinaUSA
David Matthew Sullivan Information and Analytics ServicesAtrium HealthCharlotteNorth CarolinaUSA
Harvey Pendell Meyers Department of Emergency MedicineAtrium Health's Carolinas Medical CenterCharlotteNorth CarolinaUSA
David Pearson Department of Emergency MedicineAtrium Health's Carolinas Medical CenterCharlotteNorth CarolinaUSA

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An antibody-based molecular switch for continuous small-molecule biosensing

We present a generalizable approach for designing biosensors that can continuously detect small-molecule biomarkers in real time and without sample preparation. This is achieved by converting existing antibodies into target-responsive "antibody-switches" that enable continuous optical biosensing. To engineer these switches, antibodies are linked to a molecular competitor through a DNA scaffold, such that competitive target binding induces scaffold switching and fluorescent signaling of changing target concentrations. As a demonstration, we designed antibody-switches that achieve rapid, sample preparation-free sensing of digoxigenin and cortisol in undiluted plasma. We showed that, by substituting the molecular competitor, we can further modulate the sensitivity of our cortisol switch to achieve detection at concentrations spanning 3.3 nanomolar to 3.3 millimolar. Last, we integrated this switch with a fiber optic sensor to achieve continuous sensing of cortisol in a buffer and blood with <5-min time resolution. We believe that this modular sensor design can enable continuous biosensor development for many biomarkers.

Personalized diagnosis in suspected myocardial infarction

BACKGROUND

In suspected myocardial infarction (MI), guidelines recommend using high-sensitivity cardiac troponin (hs-cTn)-based approaches. These require fixed assay-specific thresholds and timepoints, without directly integrating clinical information. Using machine-learning techniques including hs-cTn and clinical routine variables, we aimed to build a digital tool to directly estimate the individual probability of MI, allowing for numerous hs-cTn assays.

METHODS

In 2,575 patients presenting to the emergency department with suspected MI, two ensembles of machine-learning models using single or serial concentrations of six different hs-cTn assays were derived to estimate the individual MI probability (ARTEMIS model). Discriminative performance of the models was assessed using area under the receiver operating characteristic curve (AUC) and logLoss. Model performance was validated in an external cohort with 1688 patients and tested for global generalizability in 13 international cohorts with 23,411 patients.

RESULTS

Eleven routinely available variables including age, sex, cardiovascular risk factors, electrocardiography, and hs-cTn were included in the ARTEMIS models. In the validation and generalization cohorts, excellent discriminative performance was confirmed, superior to hs-cTn only. For the serial hs-cTn measurement model, AUC ranged from 0.92 to 0.98. Good calibration was observed. Using a single hs-cTn measurement, the ARTEMIS model allowed direct rule-out of MI with very high and similar safety but up to tripled efficiency compared to the guideline-recommended strategy.

CONCLUSION

We developed and validated diagnostic models to accurately estimate the individual probability of MI, which allow for variable hs-cTn use and flexible timing of resampling. Their digital application may provide rapid, safe and efficient personalized patient care.

TRIAL REGISTRATION NUMBERS

Data of following cohorts were used for this project: BACC ( www.

CLINICALTRIALS

gov ; NCT02355457), stenoCardia ( www.

CLINICALTRIALS

gov ; NCT03227159), ADAPT-BSN ( www.australianclinicaltrials.gov.au ; ACTRN12611001069943), IMPACT ( www.australianclinicaltrials.gov.au , ACTRN12611000206921), ADAPT-RCT ( www.anzctr.org.au ; ANZCTR12610000766011), EDACS-RCT ( www.anzctr.org.au ; ANZCTR12613000745741); DROP-ACS ( https://www.umin.ac.jp , UMIN000030668); High-STEACS ( www.

CLINICALTRIALS

gov ; NCT01852123), LUND ( www.

CLINICALTRIALS

gov ; NCT05484544), RAPID-CPU ( www.

CLINICALTRIALS

gov ; NCT03111862), ROMI ( www.

CLINICALTRIALS

gov ; NCT01994577), SAMIE ( https://anzctr.org.au ; ACTRN12621000053820), SEIGE and SAFETY ( www.

CLINICALTRIALS

gov ; NCT04772157), STOP-CP ( www.

CLINICALTRIALS

gov ; NCT02984436), UTROPIA ( www.

CLINICALTRIALS

gov ; NCT02060760).

Cell-free DNA as a potential biomarker for acute myocardial infarction: A systematic review and meta-analysis

BACKGROUND

Tissue necrosis releases cell-free deoxyribonucleic acid (cfDNA), leading to rapid increases in plasma concentration with clearance independent of kidney function.

AIM

To explore the diagnostic role of cfDNA in acute myocardial infarction (AMI).

METHODS

This systematic review and meta-analysis included studies of cfDNA in patients with AMI and a comparator group without AMI. The quality assessment of diagnostic accuracy studies-2 (QUADAS-2) tool was used, with AMI determined from the criteria of the original study. Standardised mean differences (SMD) were obtained using a random-effects inverse variance model. Heterogeneity was reported as I2. Pooled sensitivity and specificity were computed using a bivariate model. The area under the curve (AUC) was estimated from a hierarchical summary receiver operating characteristics curve.

RESULTS

Seventeen studies were identified involving 1804 patients (n = 819 in the AMI group, n = 985 in the comparator group). Circulating cfDNA concentrations were greater in the AMI group (SMD 3.47 (95%CI: 2.54-4.41, p < 0.001)). The studies were of variable methodological quality with substantial heterogeneity (I2 = 98%, p < 0.001), possibly due to the differences in cfDNA quantification methodologies (Chi2 25.16, p < 0.001, I2 = 92%). Diagnostic accuracy was determined using six studies (n = 804), which yielded a sensitivity of 87% (95%CI: 72%-95%) and specificity of 96% (95%CI: 92%-98%). The AUC was 0.96 (95%CI: 0.93-0.98). Two studies reported a relationship between peak cfDNA and peak troponin. No studies reported data for patients with pre-existing kidney impairment.

CONCLUSION

Plasma cfDNA appears to be a reliable biomarker of myocardial injury. Inferences from existing results are limited owing to methodology heterogeneity.

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.

Unlocking the Potential of Stroke Blood Biomarkers: Early Diagnosis, Ischemic vs. Haemorrhagic Differentiation and Haemorrhagic Transformation Risk: A Comprehensive Review

Stroke, a complex and heterogeneous disease, is a leading cause of morbidity and mortality worldwide. The timely therapeutic intervention significantly impacts patient outcomes, but early stroke diagnosis is challenging due to the lack of specific diagnostic biomarkers. This review critically examines the literature for potential biomarkers that may aid in early diagnosis, differentiation between ischemic and hemorrhagic stroke, and prediction of hemorrhagic transformation in ischemic stroke. After a thorough analysis, four promising biomarkers were identified: Antithrombin III (ATIII), fibrinogen, and ischemia-modified albumin (IMA) for diagnostic purposes; glial fibrillary acidic protein (GFAP), micro RNA 124-3p, and a panel of 11 metabolites for distinguishing between ischemic and hemorrhagic stroke; and matrix metalloproteinase-9 (MMP-9), s100b, and interleukin 33 for predicting hemorrhagic transformation. We propose a biomarker panel integrating these markers, each reflecting different pathophysiological stages of stroke, that could significantly improve stroke patients' early detection and treatment. Despite promising results, further research and validation are needed to demonstrate the clinical utility of this proposed panel for routine stroke treatment.

Rising and Falling High-Sensitivity Cardiac Troponin in Diagnostic Algorithms for Patients With Suspected Myocardial Infarction

Background High-sensitivity cardiac troponin (hs-cTn)-based diagnostic algorithms are recommended for the management of patients with suspected myocardial infarction (MI) without ST elevation. Although mirroring different phases of myocardial injury, falling and rising troponin patterns (FPs and RPs, respectively) are equally considered by most algorithms. We aimed to compare the performance of diagnostic protocols for RPs and FPs, separately. Methods and Results We pooled 2 prospective cohorts of patients with suspected MI and stratified patients to stable, FP, and RP during serial sampling separately for hs-cTnI and hs-cTnT and applied the European Society of Cardiology 0/1- and 0/3-hour algorithms comparing the positive predictive values to rule in MI. Overall, 3523 patients were included in the hs-cTnI study population. The positive predictive value for patients with an FP was significantly reduced compared with patients with an RP (0/1-hour: FP, 53.3% [95% CI, 45.0-61.4] versus RP, 76.9 [95% CI, 71.6-81.7]; 0/3-hour: FP, 56.9% [95% CI, 42.2-70.7] versus RP, 78.1% [95% CI, 74.0-81.8]). The proportion of patients in the observe zone was larger in the FP using 0/1-hour (31.3% versus 55.8%) and 0/3-hour (14.6% versus 38.6%) algorithms. Alternative cutoffs did not improve algorithm performances. Compared with stable hs-cTn, the risk for death or MI was highest in those with an FP (adjusted hazard ratio [HR], hs-cTnI 2.3 [95% CI, 1.7-3.2]; RP adjusted HR, hs-cTnI 1.8 [95% CI, 1.4-2.4]). Findings were similar for hs-cTnT tested in 3647 patients overall. Conclusions The positive predictive value to rule in MI by the European Society of Cardiology 0/1- and 0/3-hour algorithms is significantly lower in patients with FP than RP. These are at highest risk for incident death or MI. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT02355457, NCT03227159.

Machine learning for diagnosis of myocardial infarction using cardiac troponin concentrations

Although guidelines recommend fixed cardiac troponin thresholds for the diagnosis of myocardial infarction, troponin concentrations are influenced by age, sex, comorbidities and time from symptom onset. To improve diagnosis, we developed machine learning models that integrate cardiac troponin concentrations at presentation or on serial testing with clinical features and compute the Collaboration for the Diagnosis and Evaluation of Acute Coronary Syndrome (CoDE-ACS) score (0-100) that corresponds to an individual's probability of myocardial infarction. The models were trained on data from 10,038 patients (48% women), and their performance was externally validated using data from 10,286 patients (35% women) from seven cohorts. CoDE-ACS had excellent discrimination for myocardial infarction (area under curve, 0.953; 95% confidence interval, 0.947-0.958), performed well across subgroups and identified more patients at presentation as low probability of having myocardial infarction than fixed cardiac troponin thresholds (61 versus 27%) with a similar negative predictive value and fewer as high probability of having myocardial infarction (10 versus 16%) with a greater positive predictive value. Patients identified as having a low probability of myocardial infarction had a lower rate of cardiac death than those with intermediate or high probability 30 days (0.1 versus 0.5 and 1.8%) and 1 year (0.3 versus 2.8 and 4.2%; P < 0.001 for both) from patient presentation. CoDE-ACS used as a clinical decision support system has the potential to reduce hospital admissions and have major benefits for patients and health care providers.

Implementation of High-Sensitivity Troponin with a Rapid Diagnostic Algorithm Reduces Emergency Department Length of Stay for Discharged Patients

INTRODUCTION

High sensitivity troponin (hs-cTn) and diagnostic algorithms are used to rapidly triage patients with symptoms of acute myocardial infarction in emergency departments (ED). However, few studies have evaluated the impact of simultaneously implementing hs-cTn and a rapid rule-out algorithm on length of stay (LOS).

METHODS

We assessed the impact of transitioning from contemporary cTnI to hs-cTnI in 59,232 ED encounters over three years. hs-cTnI was implemented with an orderable series that included baseline, two-, four-, and six-hour specimens collected at provider discretion and operationalized with an algorithm to calculate the change in hs-cTnI from baseline and provide interpretations of "insignificant", "significant," or "equivocal." Patient demographics, results, chief complaint, disposition, and ED LOS were captured from the electronic medical record.

RESULTS

cTnI was ordered for 31,875 encounters prior to hs-cTnI implementation and 27,357 after. The proportion of cTnI results above the 99th percentile upper reference limit decreased from 35.0% to 27.0% for men and increased from 27.8% to 34.8% for women. Among discharged patients, the median LOS decreased by 0.6 h (0.5-0.7). LOS among discharged patients with a chief complaint of chest pain decreased by 1.0 h (0.8-1.1) and further decreased by 1.2 h (1.0-1.3) if the initial hs-cTnI was below the limit of quantitation. The rate of acute coronary syndrome upon re-presentation within 30 days did not change post-implementation (0.10% versus 0.07%).

CONCLUSION

Implementation of an hs-cTnI assay with a rapid rule-out algorithm decreased ED LOS among discharged patients, particularly among those with a chief complaint of chest pain.

Quantitative proteomic analysis of human serum using tandem mass tags to predict cardiovascular risks in patients with psoriasis

Although biomarker candidates associated with psoriasis have been suggested, those for predicting the risk of cardiovascular disease (CVD) early in patients with psoriasis are lacking. We aimed to identify candidate biomarkers that can predict the occurrence of CVD in psoriasis patients. We pursued quantitative proteomic analysis of serum samples composed of three groups: psoriasis patients with and those without CVD risk factors, and healthy controls. Age/Sex-matched serum samples were selected and labeled with 16-plex tandem mass tag (TMT) and analyzed using liquid chromatography-mass spectrometry and subsequent verification with ELISA. Of the 184 proteins that showed statistical significance (P-value < 0.05) among the three groups according to TMT-based quantitative analysis, 98 proteins showed significant differences (> 2.0-fold) between the psoriasis groups with and without CVD risk factors. Verification by ELISA revealed that caldesmon (CALD1), myeloid cell nuclear differentiation antigen (MNDA), and zyxin (ZYX) levels were significantly increased in the psoriasis group with CVD risk factors. Further network analysis identified pathways including integrin signaling, which could be related to platelet aggregation, and actin cytoskeleton signaling. Three novel candidates (MNDA, ZYX, and CALD1) could be potential biomarkers for predicting CVD risks in psoriasis patients. We expect these biomarker candidates can be used to predict CVD risk in psoriasis patients in clinical settings although further studies including large validation are needed.

Development of a Point-of-Care SPR Sensor for the Diagnosis of Acute Myocardial Infarction

A novel point-of-care surface plasmon resonance (SPR) sensor was developed for the sensitive and real-time detection of cardiac troponin I (cTnI) using epitope-imprinted molecular receptors. The surface coverage of a nano-molecularly imprinted polymer (nanoMIP)-functionalized SPR sensor chip and the size of nanoMIPs (155.7 nm) were characterized using fluorescence microscopy and dynamic light scattering techniques, respectively. Atomic force microscopy, electrochemical impedance spectroscopy, square wave voltammetry and cyclic voltammetry techniques confirmed the successful implementation of each step of the sensor fabrication. The SPR bio-detection assay was initially established by targeting the cTnI peptide template, and the sensor allowed the detection of the peptide in the concentration range of 100-1000 nM with a correlation coefficient (R²) of 0.96 and limit of detection (LOD) of 76.47 nM. The optimum assay conditions for protein recognition were subsequently determined, and the cTnI biomarker could be detected in a wide concentration range (0.78-50 ng mL^-1) with high reproducibility (R² = 0.91) and sensitivity (LOD: 0.52 ng mL^-1). The overall sensor results were subjected to three binding isotherm models, where nanoMIP-cTnI interaction followed the Langmuir binding isotherm with the dissociation constant of 2.99 × 10^-11 M, indicating a very strong affinity between the cTnI biomarker and epitope-imprinted synthetic receptor. Furthermore, the selectivity of the sensor was confirmed through studying with a control nanoMIP that was prepared by imprinting a non-specific peptide template. Based on the cross-reactivity tests with non-specific molecules (i.e., glucose, p53 protein, transferrin and bovine serum albumin), the nanoMIP-SPR sensor is highly specific for the target biomarker. The developed biomimetic sensor, relying on the direct assay strategy, holds great potential not only for the early and point-of-care testing of acute myocardial infarction but also for other life-threatening diseases that can be diagnosed by determining the elevated levels of certain biomarkers.

Serum levels of copeptin predict adverse outcomes and improve risk prediction of TRISS and MGAP scores in patients with multiple trauma: A single-center prospective cohort study

BACKGROUND

Multiple trauma deserves early prognostication and stratification. Copeptin, a precursor of vasopressin, is produced in response to stress. We examined the association between serum levels of copeptin and mortality risk in patients with multiple trauma. We aimed to also enhance the previously established Trauma-Related Injury Severity Score (TRISS) and Mechanism, GCS, Age, and Arterial Pressure (MGAP) score with the additional consideration of copeptin levels.

METHODS

This single-center prospective cohort study enrolled patients who presented to the emergency department with potential major injuries. The serum levels of copeptin were measured, and the correlation to clinical severity in terms of 30-day mortality and requirement of intensive care management was analyzed. By combining copeptin levels with TRISS or MGAP, comparison between performance of the original models with the copeptin-enhanced models was performed via discrimination, calibration, and reclassification analyses.

RESULTS

There was a significant increase in copeptin levels in patients who died within 30 days (median 644.4 pg/L, interquartile range [472.5, 785.9]) or were admitted to intensive care units (233.8 pg/L, [105.7, 366.4]), compared with those who survived (37.49 pg/L, [17.88, 77.68]). Adding the natural log of copeptin levels to the established TRISS and MGAP models improved the AUC of TRISS from 0.89 to 0.96, and that of MGAP from 0.82 to 0.95. Both calibrations as measured by Brier's scores and reclassification as measured by net reclassification improvement or integrated discrimination improvement demonstrated significant improvements. A Web-based calculator was built to generate predicted mortality rates of various models for convenient clinical use.

CONCLUSION

Admission serum copeptin levels were correlated with clinical severity in multiple trauma. Coupling copeptin with preexisting trauma severity scores improved prediction accuracy. Copeptin shows promise as a novel biomarker for the prediction of trauma outcome.

LEVEL OF EVIDENCE

Prognostic and Epidemiologic; Level III.

Implementation of High-Sensitivity Cardiac Troponin Assays in the United States

BACKGROUND

Few data exist regarding the implementation of high-sensitivity cardiac troponin (hs-cTn) assays in the United States since their approval.

OBJECTIVES

This study sought to explore trends in hs-cTn assay implementation over time and assess the association of their use with in-hospital cardiac testing and outcomes.

METHODS

The study examined trends in implementation of hs-cTn assays among participating hospitals in the National Cardiovascular Data Registry Chest Pain-MI [Myocardial Infarction] Registry from January 1, 2019 through September 30, 2021. Associations among hs-cTn use, use of in-hospital diagnostic imaging, and patient outcomes were assessed using generalized estimating equation models with logistic or gamma distributions.

RESULTS

Among 550 participating hospitals (N = 251,000), implementation of hs-cTn assays increased from 3.3% in the first quarter of 2019 to 32.6% in the third quarter of 2021 (Ptrend < 0.001). Use of hs-cTn was associated with more echocardiography among persons with non-ST-segment elevation acute coronary syndrome (NSTE-ACS; 82.4% vs 75.0%; adjusted odds ratio: 1.43; 95% CI: 1.19-1.73) but not among low-risk chest pain individuals. Use of hs-cTn was associated with less invasive coronary angiography among low-risk patients (3.7% vs 4.5%; adjusted odds ratio: 0.73; 95% CI: 0.58-0.92) but similar use for patients with NSTE-ACS. There was no association between hs-cTn use and noninvasive stress testing or coronary computed tomography angiography testing. Among individuals with NSTE-ACS, hs-cTn use was not associated with revascularization or in-hospital mortality. Use of hs-cTn was associated with a shorter length of stay (median 47.6 hours vs 48.0 hours; ratio: 0.94; 95% CI: 0.90-0.98).

CONCLUSIONS

Implementation of hs-cTn among U.S. hospitals is increasing, but most U.S. hospitals continue to use less sensitive assays. The use of hs-cTn was associated with modestly shorter length of stay, greater use of echocardiography for NSTE-ACS, and less use of invasive angiography among low-risk patients.

Intact Transition Epitope Mapping-Force Differences between Original and Unusual Residues (ITEM-FOUR)

Antibody-based point-of-care diagnostics have become indispensable for modern medicine. In-depth analysis of antibody recognition mechanisms is the key to tailoring the accuracy and precision of test results, which themselves are crucial for targeted and personalized therapy. A rapid and robust method is desired by which binding strengths between antigens and antibodies of concern can be fine-mapped with amino acid residue resolution to examine the assumedly serious effects of single amino acid polymorphisms on insufficiencies of antibody-based detection capabilities of, e.g., life-threatening conditions such as myocardial infarction. The experimental ITEM-FOUR approach makes use of modern mass spectrometry instrumentation to investigate intact immune complexes in the gas phase. ITEM-FOUR together with molecular dynamics simulations, enables the determination of the influences of individually exchanged amino acid residues within a defined epitope on an immune complex's binding strength. Wild-type and mutated epitope peptides were ranked according to their experimentally determined dissociation enthalpies relative to each other, thereby revealing which single amino acid polymorphism caused weakened, impaired, and even abolished antibody binding. Investigating a diagnostically relevant human cardiac Troponin I epitope for which seven nonsynonymous single nucleotide polymorphisms are known to exist in the human population tackles a medically relevant but hitherto unsolved problem of current antibody-based point-of-care diagnostics.

Computed tomography coronary angiography after excluding myocardial infarction: high-sensitivity troponin versus risk score-guided approach

BACKGROUND

Patients with suspected acute coronary syndrome (ACS) in whom myocardial infarction has been ruled out are still at risk of having obstructive coronary artery disease (CAD). This rate is higher among patients with intermediate high-sensitivity troponin I (hsTnI) concentrations (5 ng/L to 99th percentile) than low concentrations (<5 ng/L). Therefore, an intermediate concentration has been suggested as a candidate for downstream investigation with computed tomography coronary angiography (CTCA). We tried to compare the HEART score-guided vs. hsTnI-guided approach for identifying obstructive CAD.

METHODS

From a prospective cohort study of patients presenting to the emergency department with suspected ACS, 433 patients without elevated hsTnI who also underwent CTCA were selected and analyzed. The performances of hsTnI concentration and HEART score were compared using sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

Overall, 120 (27.7%) patients had obstructive CAD. Patients with intermediate hsTnI concentrations were more likely to have obstructive CAD than those with low hsTnI concentrations (40.0% vs. 18.1%); patients with non-low-risk HEART scores (≥4 points) were also more likely to have obstructive CAD than those with low-risk scores (0 to 3 points) (41.0% vs. 7.6%). The HEART score had higher sensitivity and NPV for detecting obstructive CAD in each classification than hsTnI concentration (sensitivity: 89.2% vs. 63.3% NPV: 92.4% vs. 81.9%, respectively).

CONCLUSION

After excluding myocardial infarction in patients with suspected ACS, adding the HEART score for selecting candidates for CTCA could improve patient risk stratification more accurately than relying on hsTnI concentration.

Oxygen administration during surgery and postoperative organ injury: observational cohort study

OBJECTIVE

To examine whether supraphysiological oxygen administration during surgery is associated with lower or higher postoperative kidney, heart, and lung injury.

DESIGN

Observational cohort study.

SETTING

42 medical centers across the United States participating in the Multicenter Perioperative Outcomes Group data registry.

PARTICIPANTS

Adult patients undergoing surgical procedures ≥120 minutes' duration with general anesthesia and endotracheal intubation who were admitted to hospital after surgery between January 2016 and November 2018.

INTERVENTION

Supraphysiological oxygen administration, defined as the area under the curve of the fraction of inspired oxygen above air (21%) during minutes when the hemoglobin oxygen saturation was greater than 92%.

MAIN OUTCOMES

Primary endpoints were acute kidney injury defined using Kidney Disease Improving Global Outcomes criteria, myocardial injury defined as serum troponin >0.04 ng/mL within 72 hours of surgery, and lung injury defined using international classification of diseases hospital discharge diagnosis codes.

RESULTS

The cohort comprised 350 647 patients with median age 59 years (interquartile range 46-69 years), 180 546 women (51.5%), and median duration of surgery 205 minutes (interquartile range 158-279 minutes). Acute kidney injury was diagnosed in 19 207 of 297 554 patients (6.5%), myocardial injury in 8972 of 320 527 (2.8%), and lung injury in 13 789 of 312 161 (4.4%). The median fraction of inspired oxygen was 54.0% (interquartile range 47.5%-60.0%), and the area under the curve of supraphysiological inspired oxygen was 7951% min (5870-11 107% min), equivalent to an 80% fraction of inspired oxygen throughout a 135 minute procedure, for example. After accounting for baseline covariates and other potential confounding variables, increased oxygen exposure was associated with a higher risk of acute kidney injury, myocardial injury, and lung injury. Patients at the 75th centile for the area under the curve of the fraction of inspired oxygen had 26% greater odds of acute kidney injury (95% confidence interval 22% to 30%), 12% greater odds of myocardial injury (7% to 17%), and 14% greater odds of lung injury (12% to 16%) compared with patients at the 25th centile. Sensitivity analyses evaluating alternative definitions of the exposure, restricting the cohort, and conducting an instrumental variable analysis confirmed these observations.

CONCLUSIONS

Increased supraphysiological oxygen administration during surgery was associated with a higher incidence of kidney, myocardial, and lung injury. Residual confounding of these associations cannot be excluded.

TRIAL REGISTRATION

Open Science Framework osf.io/cfd2m.

Serum troponin is elevated in acute decompensation and acute-on-chronic liver failure and is associated with severity of liver disease and short-term mortality

BACKGROUND

The role of high sensitive cardiac Troponin (hs-cTn) in patients with liver cirrhosis (LC) and liver-related acute events is not well established.

AIM

To assess the prognostic performance of hs-cTn I in acute decompensation (AD) and acute-on-chronic liver failure (ACLF).

METHODS

Two cohorts of consecutive patients, a derivation (retrospective) and a validation (prospective), were evaluated and 30-day-mortality was recorded. Hs-cTnI values were measured. Very low hs-cTnΙ (4 ng/L) was considered the cutoff-level.

RESULTS

A total of 296 patients with LC [69.3% male, median age 57 (IQR 51-68) years, MELD score 19 (13-25), ACLF (29.4%), AD (48.3%), and without liver-related acute events (22.3%)] were included in the derivation cohort. The 66.2% of total patients had hs-cTnI ≥4 ng/L. Patients with hs-cTnI ≥4 ng/L were older and had more severe LC compared to those with <4ng/L. The multivariate analysis demonstrated that age (p < 0.001) and MELD (p = 0.001) were independent variables associated with elevated hs-cTnI after adjustment for age, sex and hepatic encephalopathy in total patients.When ACLF and AD were analyzed separately, the mortality was higher in patients with hs-cTnI ≥ 4 ng/L compared to lower values (log-rank p = 0.036 and p = 0.019, respectively). In multivariate analysis, MELD (p < 0.001) and hs-cTnI ≥4 ng/L (p = 0.032) were independent prognostic factors of mortality in ACLF/AD groups, after adjustment for age and sex. Similar results were obtained from the validation cohort (N = 148).

CONCLUSIONS

hs-cTnI levels were higher in patients with severe liver disease. The low cutoff-point of 4 ng/L is accurate in ruling out non-survivors mainly in AD group.

Epicardial Adipose Tissue Thickness Is Related to Plaque Composition in Coronary Artery Disease

(1) Background: Currently, limited data are available regarding the relationship between epicardial fat and plaque composition. The aim of this study was to assess the relationship between visceral fat surrounding the heart and the lipid core burden in patients with coronary artery diseases; (2) Methods: Overall, 331 patients undergoing coronary angiography with combined near-infrared spectroscopy and intravascular ultrasound imaging were evaluated for epicardial adipose tissue (EAT) thickness using transthoracic echocardiography. Patients were divided into thick EAT and thin EAT groups according to the median value; (3) Results: There was a positive correlation between EAT thickness and maxLCBI4mm, and maxLCBI4mm was significantly higher in the thick EAT group compared to the thin EAT group (437 vs. 293, p < 0.001). EAT thickness was an independent predictor of maxLCBI4mm ≥ 400 along with age, low-density lipoprotein-cholesterol level, acute coronary syndrome presentation, and plaque burden in a multiple linear regression model. Receiver operating characteristic curve analysis showed that EAT thickness was a predictor for maxLCBI4mm ≥ 400; (4) Conclusions: In the present study, EAT thickness is related to the lipid core burden assessed by NIRS-IVUS in patients with CAD which suggests that EAT may affect the stability of the plaques in coronary arteries.

Cardiac troponins - a paradigm for diagnostic biomarker identification and development

The introduction of cardiac troponins into clinical diagnostics has not only improved diagnostic pathways for myocardial infarction but also profoundly influenced the definition of myocardial infarction. The term troponin appeared in the literature almost 60 years ago, i.e. shortly after this journal was founded. The development of cardiac troponins from proteins involved in muscle contraction, which were in the focus of few specialized research groups from physiology and biochemistry, to one of the most frequently measured protein biomarkers in medicine is a paradigmatic success story which is also reflected in almost 300 publications on the topic in this journal. From the viewpoint of biomarker development the critical success factors were medical need, timely generation of medical evidence, and the rapid development of robust and precise laboratory assays.

Prognostic Value of High-Sensitivity Cardiac Troponin in Women

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

A review of cardiac troponin I detection by surface enhanced Raman spectroscopy: Under the spotlight of point-of-care testing

Cardiac troponin I (cTnI) is a biomarker widely related to acute myocardial infarction (AMI), one of the leading causes of death around the world. Point-of-care testing (POCT) of cTnI not only demands a short turnaround time for its detection but the highest accuracy levels to set expeditious and adequate clinical decisions. The analytical technique Surface-enhanced Raman spectroscopy (SERS) possesses several properties that tailor to the POCT format, such as its flexibility to couple with rapid assay platforms like microfluidics and paper-based immunoassays. Here, we analyze the strategies used for the detection of cTnI by SERS considering POCT requirements. From the detection ranges reported in the reviewed literature, we suggest the diseases other than AMI that could be diagnosed with this technique. For this, a section with information about cardiac and non-cardiac diseases with cTnI release, including their release kinetics or cut-off values are presented. Likewise, POCT features, the use of SERS as a POCT technique, and the biochemistry of cTnI are discussed. The information provided in this review allowed the identification of strengths and lacks of the available SERS-based point-of-care tests for cTnI and the disclosing of requirements for future assays design.

Label-free detection of cardiac troponin-I with packaged thin-walled microbubble resonators

The measurement of cardiac troponin-I (cTnI) is widely used for diagnosing acute myocardial infarction (AMI) diseases because of its myocardial specificity. Packaged microbubble resonators with thin wall are utilized for label-free and specific detection of cTnI based on whispering gallery mode (WGM). This packaged structure can provide a good protection for the biosensor, improve the anti-interference ability of the sensor and reduce the system noise. The theoretical detection limit of the biosensors for cTnI in phosphate buffer saline (PBS) is 0.4 ag mL^-1 (0.02 a_M ). Furthermore, we demonstrated that the biosensors can be used to detect cTnI molecules in simulated serum and the theoretical detection limit is also 0.4 ag mL^-1 (0.02 a_M ). These results are much far below the clinical cut-off value and show a huge application potential for the detection of cardiac biomarkers of AMI.

Acute coronary syndrome prediction in emergency care: A machine learning approach

BACKGROUND AND OBJECTIVE

Clinical concern for acute coronary syndrome (ACS) is one of emergency medicine's most common patient encounters. This study aims to develop an ensemble learning-driven framework as a diagnostic support tool to prevent misdiagnosis.

METHODS

We obtained extensive clinical electronic health data on patient encounters with clinical concerns for ACS from a large urban emergency department (ED) between January 2017 and August 2020. We applied an analytical framework equipped with many well-developed algorithms to improve the data quality by addressing missing values, dimensionality reduction, and data imbalance. We trained ensemble learning algorithms to classify patients with ACS or non-ACS etiologies of their symptoms. We used performance evaluation metrics such as accuracy, sensitivity, precision, F1-score, and the area under the receiver operating characteristic (AUROC) to measure the model's performance.

RESULTS

The analysis included 31,228 patients, of whom 563 (1.8%) had ACS and 30,665 (98.2%) had alternative diagnoses. Eleven features, including systolic blood pressure, brain natriuretic peptide, chronic heart disease, coronary artery disease, creatinine, glucose, heart attack, heart rate, nephrotic syndrome, red cell distribution width, and troponin level, are reported as significantly contributing risk factors. The proposed framework successfully classifies these cohorts with sensitivity and AUROC as high as 86.3% and 93.3%. Our proposed model's accuracy, precision, specificity, Matthew's correlation coefficient, and F1-score were 85.7%, 86.3%, 93%, 80%, and 86.3%, respectively.

CONCLUSION

Our proposed framework can identify early patients with ACS through further refinement and validation.

Identifying Genes Related to Acute Myocardial Infarction Based on Network Control Capability

Identifying genes significantly related to diseases is a focus in the study of disease mechanisms. In this paper, from the perspective of integrated analysis and dynamic control, a method for identifying genes significantly related to diseases based on logic networks constructed by the LAPP method, referred to as NCCM, is proposed and applied to the study of the mechanism of acute myocardial infarction (AMI). It is found that 82.35% of 17 differential control capability genes (DCCGs) identified by NCCM are significantly correlated with AMI/MI in the literature and DISEASES database. The enrichment analysis of DCCGs shows that AMI is closely related to the positive regulation of vascular-associated smooth muscle cell proliferation and regulation of cytokine production involved in the immune response, in which HBEGF, THBS1, NR4A3, NLRP3, EDN1, and MMP9 play a crucial role. In addition, although the expression levels of CNOT6L and ACYP1 are not significantly different between the control group and the AMI group, NCCM shows that they are significantly associated with AMI. Although this result still needs further verification, it shows that the method can not only identify genes with large differences in expression but also identify genes that are associated with diseases but with small changes in expression.

The Prognostic Value of Cardiac Troponin I in Patients with or without Three-Vessel Disease Undergoing Complete Percutaneous Coronary Intervention

Postprocedural cardiac troponin I (cTnI) elevation commonly occurs in patients undergoing percutaneous coronary intervention (PCI); however, its prognostic value remains controversial. This study aimed to investigate the prognostic value of peak postprocedural cTnI in cardiac patients with or without three-vessel disease (TVD) undergoing complete PCI. A total of 1237 consecutive patients (77% males, mean age 58 ± 10 years) with normal baseline cTnI levels were enrolled, 439 patients (77% males, 59 ± 10 years) with TVD, and 798 patients (77% males, 57 ± 10 years) with single- or double-vessel disease (non-TVD). The primary outcome was the occurrence of major adverse cardiovascular events (MACE), defined as a composite of non-fatal MI, non-fatal stroke, unplanned revascularization, re-hospitalization due to heart failure or severe arrhythmias, and all-cause death. During the median follow-up of 5.3 years, a total of 169 patients (13.7%) developed MACE, including 73 (16.6%) in the TVD group and 96 (12.0%) in the non-TVD group (p = 0.024). After adjustment, the multivariate Cox analysis showed that hypertension (HR 1.50; 95% CI: 1.01–2.20; p = 0.042), TVD (HR 1.44; 95% CI: 1.03–2.02; p = 0.033), and cTnI ≥ 70× URL (HR 2.47; 95% CI: 1.28–4.78, p = 0.007) were independently associated with increased MACE during long-term follow-up. Further subgroup analyses showed that cTnI ≥ 70× URL was an independent predictor of MACE in TVD patients (HR 3.32, 95% CI: 1.51–7.34, p = 0.003), but not in non-TVD patients (HR 1.01, 95%CI: 0.24–4.32, p = 0.991). In conclusion, elevation of post-PCI cTnI ≥ 70× URL is independently associated with a high risk of MACE during long-term follow-up in patients with TVD, but not in those with non-TVD.

Cardiovascular Biomarkers: Lessons of the Past and Prospects for the Future

Cardiovascular diseases (CVDs) are a major healthcare burden on the population worldwide. Early detection of this disease is important in prevention and treatment to minimise morbidity and mortality. Biomarkers are a critical tool to either diagnose, screen, or provide prognostic information for pathological conditions. This review discusses the historical cardiac biomarkers used to detect these conditions, discussing their application and their limitations. Identification of new biomarkers have since replaced these and are now in use in routine clinical practice, but still do not detect all disease. Future cardiac biomarkers are showing promise in early studies, but further studies are required to show their value in improving detection of CVD above the current biomarkers. Additionally, the analytical platforms that would allow them to be adopted in healthcare are yet to be established. There is also the need to identify whether these biomarkers can be used for diagnostic, prognostic, or screening purposes, which will impact their implementation in routine clinical practice.

Multiplex Label-Free Kinetic Characterization of Antibodies for Rapid Sensitive Cardiac Troponin I Detection Based on Functionalized Magnetic Nanotags

Express and highly sensitive immunoassays for the quantitative registration of cardiac troponin I (cTnI) are in high demand for early point-of-care differential diagnosis of acute myocardial infarction. The selection of antibodies that feature rapid and tight binding with antigens is crucial for immunoassay rate and sensitivity. A method is presented for the selection of the most promising clones for advanced immunoassays via simultaneous characterization of interaction kinetics of different monoclonal antibodies (mAb) using a direct label-free method of multiplex spectral correlation interferometry. mAb-cTnI interactions were real-time registered on an epoxy-modified microarray glass sensor chip that did not require activation. The covalent immobilization of mAb microdots on its surface provided versatility, convenience, and virtually unlimited multiplexing potential. The kinetics of tracer antibody interaction with the “cTnI—capture antibody” complex was characterized. Algorithms are shown for excluding mutual competition of the tracer/capture antibodies and selecting the optimal pairs for different assay formats. Using the selected mAbs, a lateral flow assay was developed for rapid quantitative cTnI determination based on electronic detection of functionalized magnetic nanoparticles applied as labels (detection limit—0.08 ng/mL, dynamic range > 3 orders). The method can be extended to other molecular biomarkers for high-throughput screening of mAbs and rational development of immunoassays.

Tropisetron Preconditioning Decreases Myocardial Biomarkers in Patients Undergoing Heart Valve Replacement Surgery

Background

Cardioplegic arrest during the heart valve replacement surgery frequently leads to myocardial damage. Tropisetron (TRP) has been demonstrated to reduce myocardial ischemia-reperfusion injury and inflammation in animals. We examined the efficacy of TRP in lowering myocardial biomarkers in patients undergoing heart valve replacement surgery.

Methods

A total of seventy-five patients, scheduled for elective heart valve replacement surgery, were randomly chosen to receive either 10 ml of normal saline or 10 mg/10 ml of TRP immediately after anesthesia induction. Blood samples for the measurement of cardiac troponin I (cTnI), creatine kinase (CK-MB), lactate dehydrogenase (LDH), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-10 (IL-10) were taken before anesthesia, as well as 4, 12, and 24 h after aortic cross-clamp release to evaluate myocardial injury using two-way ANOVA for repeated measurements. The study was registered at www.chictr.org.cn (number, ChiCTR-1800018681).

Results

Treatment with TRP decreased the increment of cTnI (Fgroup = 4.911, p = 0.030; Ftime = 55.356, p = 0.001; Fgroup × time = 5.340, p = 0.002) at 12 and 24 h; of CK-MB (Fgroup = 6.552, p = 0.013; Ftime = 49.276, p = 0.001; Fgroup × time = 7.627, p = 0.003) at 4, 12, and 24 h; of TNF-α (Fgroup = 4.153, p = 0.046; Ftime = 28.244, p = 0.002; Fgroup × time = 4.692, p = 0.006) at 4 and 12 h; and of LDH (Fgroup = 4.275, p = 0.043; Ftime = 63.225, p = 0.001; Fgroup × time = 2.501, p = 0.083) at 24 h after the release of the aortic cross-clamp. It increased IL-10 (Fgroup = 5.958, p = 0.018; Ftime = 31.226, p = 0.002; Fgroup × time = 1.464, p = 0.236) at 12 h after the release of the aortic cross-clamp. Multiple linear regression analysis showed that cardiopulmonary bypass (CPB) time was a risk factor, and that TRP treatment was a protective factor for postoperative cTNI change (β = 4.449, 95% CI [0.97–7.92], p = 0.013 for CPB time; and β = −381, 95% CI [−613.4 to −148.5], p = 0.002 for TRP treatment).

Conclusions

Tropisetron had cardioprotective and anti-inflammatory effects in patients undergoing heart valve replacement surgery with cardioplegic arrest. The addition of TRP and reduction of CPB time should be considered for myocardial protection in heart valve replacement surgery.

Clinical Trial Registration

[www.chictr.org.cn/index.aspx], identifier [ChiCTR1800018681].

Unstable Angina Pectoris With Myocardial Injury Versus Myocardial Infarction in the Era of High-Sensitivity Cardiac Troponin

It is unknown whether outcomes in patients with unstable angina pectoris (UAP) and myocardial injury are different from outcomes in patients with non-ST-segment myocardial infarction (NSTEMI) with low peak concentrations of high-sensitivity cardiac troponin T (hs-cTnT). This study aimed to compare the prognosis in patients with UAP and evidence of myocardial injury, with prognosis in patients with NSTEMI and different peak hs-cTnT concentrations. All visits to 7 different emergency departments in Sweden from December 9, 2009 to December 31, 2016 were identified (n = 5,225,075). We included all hospitalized patients with hs-cTnT >14 ng/L and a diagnosis of UAP or NSTEMI, with ≥2 hours-cTnT measurements. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated for all-cause mortality and cardiovascular events, in patients with NSTEMI categorized according to peak hs-cTnT concentrations, compared with patients with UAP. Altogether, 11,944 patients were included, of whom 1,253 (10%) received a diagnosis of UAP. During a median follow-up of 3.0 years (interquartile [IQR] 1.6 to 4.7), 3,297 patients died. There was no difference comparing patients with NSTEMI with peak hs-cTnT of 15 to 49 ng/L to patients with UAP, with regards to long-term cardiovascular mortality (HR 1.15; 95% CI, 0.85 to 1.56), but the risk of recurrent myocardial infarction was higher in patients with NSTEMI (HR, 1.61; 95% CI, 1.29 to 2.00), and the risk of heart failure hospitalization slightly lower (HR 0.80, 95% CI, 0.64 to 0.99). In conclusion, patients with UAP and myocardial injury have a similar risk of death after discharge, but a lower risk of recurrent myocardial infarction and a marginally higher risk of heart failure, compared with patients with NSTEMI with moderately elevated hs-cTnT levels.

Adding stress biomarkers to high-sensitivity cardiac troponin for rapid non-ST-elevation myocardial infarction rule-out protocols

AIMS

This study tested the hypothesis that combining stress-induced biomarkers (copeptin or glucose) with high-sensitivity cardiac troponin (hs-cTn) increases diagnostic accuracy for non-ST-elevation myocardial infarction (NSTEMI) in patients presenting to the emergency department.

METHODS AND RESULTS

The ability to rule-out NSTEMI for combinations of baseline hs-cTnT or hs-cTnI with copeptin or glucose was compared with the European Society of Cardiology (ESC) hs-cTnT/I-only rule-out algorithms in two independent (one Norwegian and one international multicentre) diagnostic studies. Among 959 patients (median age 64 years, 60.5% male) with suspected NSTEMI in the Norwegian cohort, 13% had NSTEMI. Adding copeptin or glucose to hs-cTnT/I as a continuous variable did not improve discrimination as quantified by the area under the curve {e.g. hs-cTnT/copeptin 0.91 [95% confidence interval (CI) 0.89-0.93] vs. hs-cTnT alone 0.91 (95% CI 0.89-0.93); hs-cTnI/copeptin 0.85 (95% CI 0.82-0.87) vs. hs-cTnI alone 0.93 (95% CI 0.91-0.95)}, nor did adding copeptin <9 mmol/L or glucose <5.6 mmol/L increase the sensitivity of the rule-out provided by hs-cTnT <5 ng/L or hs-cTnI <4 ng/L in patients presenting more than 3 h after chest pain onset (target population in the ESC-0 h-algorithm). The combination decreased rule-out efficacy significantly (both P < 0.01). These findings were confirmed among 1272 patients (median age 62 years, 69.3% male) with suspected NSTEMI in the international validation cohort, of which 20.7% had NSTEMI. A trend towards increased sensitivity for the hs-cTnT/I/copeptin combinations (97-100% vs. 91-97% for the ESC-0 h-rule-out cut-offs) was observed in the Norwegian cohort.

CONCLUSION

Adding copeptin or glucose to hs-cTnT/I did not increase diagnostic performance when compared with current ESC guideline hs-cTnT/I-only 0 h-algorithms.

2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

METHODS

A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing randomized and nonrandomized trials, observational studies, registries, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered.

STRUCTURE

Chest pain is a frequent cause for emergency department visits in the United States. The "2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain" provides recommendations based on contemporary evidence on the assessment and evaluation of chest pain. This guideline presents an evidence-based approach to risk stratification and the diagnostic workup for the evaluation of chest pain. Cost-value considerations in diagnostic testing have been incorporated, and shared decision-making with patients is recommended.