Control of cardiac contractions using Cre-lox and degron strategies in zebrafish.

Cardiac contractions and hemodynamic forces are essential for organ development and homeostasis. Control over cardiac contractions can be achieved pharmacologically or optogenetically. However, these approaches lack specificity or require direct access to the heart. Here, we compare two genetic approaches to control cardiac contractions by modulating the levels of the essential sarcomeric protein Tnnt2a in zebrafish. We first recombine a newly generated tnnt2a floxed allele using multiple lines expressing Cre under the control of cardiomyocyte-specific promoters, and show that it does not recapitulate the tnnt2a/silent heart mutant phenotype in embryos. We show that this lack of early cardiac contraction defects is due, at least in part, to the long half-life of tnnt2a mRNA, which masks the gene deletion effects until the early larval stages. We then generate an endogenous Tnnt2a-eGFP fusion line that we use together with the zGRAD system to efficiently degrade Tnnt2a in all cardiomyocytes. Using single-cell transcriptomics, we find that Tnnt2a depletion leads to cardiac phenotypes similar to those observed in tnnt2a mutants, with a loss of blood and pericardial flow-dependent cell types. Furthermore, we achieve conditional degradation of Tnnt2a-eGFP by splitting the zGRAD protein into two fragments that, when combined with the cpFRB2-FKBP system, can be reassembled upon rapamycin treatment. Thus, this Tnnt2a degradation line enables non-invasive control of cardiac contractions with high spatial and temporal specificity and will help further understand how they shape organ development and homeostasis.

Cardiac troponin T N-domain variant destabilizes the actin interface resulting in disturbed myofilament function.

Missense variant Ile79Asn in human cardiac troponin T (cTnT-I79N) has been associated with hypertrophic cardiomyopathy and sudden cardiac arrest in juveniles. cTnT-I79N is located in the cTnT N-terminal (TnT1) loop region and is known for its pathological and prognostic relevance. A recent structural study revealed that I79 is part of a hydrophobic interface between the TnT1 loop and actin, which stabilizes the relaxed (OFF) state of the cardiac thin filament. Given the importance of understanding the role of TnT1 loop region in Ca2+ regulation of the cardiac thin filament along with the underlying mechanisms of cTnT-I79N-linked pathogenesis, we investigated the effects of cTnT-I79N on cardiac myofilament function. Transgenic I79N (Tg-I79N) muscle bundles displayed increased myofilament Ca2+ sensitivity, smaller myofilament lattice spacing, and slower crossbridge kinetics. These findings can be attributed to destabilization of the cardiac thin filament's relaxed state resulting in an increased number of crossbridges during Ca2+ activation. Additionally, in the low Ca2+-relaxed state (pCa8), we showed that more myosin heads are in the disordered-relaxed state (DRX) that are more likely to interact with actin in cTnT-I79N muscle bundles. Dysregulation of the myosin super-relaxed state (SRX) and the SRX/DRX equilibrium in cTnT-I79N muscle bundles likely result in increased mobility of myosin heads at pCa8, enhanced actomyosin interactions as evidenced by increased active force at low Ca2+, and increased sinusoidal stiffness. These findings point to a mechanism whereby cTnT-I79N weakens the interaction of the TnT1 loop with the actin filament, which in turn destabilizes the relaxed state of the cardiac thin filament.

RNA Sequencing Screens the Key Genes and Pathways in a Mouse Model of HFpEF.

INTRODUCTION: Heart failure with preserved ejection fraction (HFpEF) is a common syndrome with high morbidity and mortality but without available evidence-based therapies. It is essential to investigate changes in gene expression profiles in preclinical HFpEF animal models, with the aim of searching for novel therapeutic targets. METHODS: Wild-type male C57BL/6J mice were administrated with a combination of high-fat diet (HFD) and inhibition of constitutive nitric oxide synthase using N-nitro-l-arginine methyl ester (l-NAME) for 5 and 7 weeks. RNA sequencing was conducted to detect gene expression profiles, and bioinformatic analysis was performed to identify the core genes, pathways, and biological processes involved. RESULTS: A total of 1,347 genes were differentially expressed in the heart at week 5 and 7 post-intervention. Gene Ontology enrichment analysis indicated that these greatly changed genes were involved mainly in cell adhesion, neutrophil chemotaxis, cell communication, and other functions. Using hierarchical cluster analysis, these differentially expressed genes were classified into 16 profiles. Of these, three significant profiles were ultimately identified. Gene co-expression network analysis suggested troponin T type 1 (Tnnt1) directly regulated 31 neighboring genes and was considered to be at the core of the associated gene network. CONCLUSION: The combined application of RNA sequencing, hierarchical cluster analysis, and gene network analysis identified Tnnt1 as the most important gene in the development of HFpEF.

Role of the interaction between troponin T and AMP deaminase by zinc bridge in modulating muscle contraction and ammonia production.

The N-terminal region of troponin T (TnT) does not bind any protein of the contractile machinery and the role of its hypervariability remains uncertain. In this review we report the evidence of the interaction between TnT and AMP deaminase (AMPD), a regulated zinc enzyme localized on the myofibril. In periods of intense muscular activity, a decrease in the ATP/ADP ratio, together with a decrease in the tissue pH, is the stimulus for the activation of the enzyme that deaminating AMP to IMP and NH3 displaces the myokinase reaction towards the formation of ATP. In skeletal muscle subjected to strong tetanic contractions, a calpain-like proteolytic activity produces the removal in vivo of a 97-residue N-terminal fragment from the enzyme that becomes desensitized towards the inhibition by ATP, leading to an unrestrained production of NH3. When a 95-residue N-terminal fragment is removed from AMPD by trypsin, simulating in vitro the calpain action, rabbit fast TnT or its phosphorylated 50-residue N-terminal peptide binds AMPD restoring the inhibition by ATP. Taking in consideration that the N-terminus of TnT expressed in human as well as rabbit white muscle contains a zinc-binding motif, we suggest that TnT might mimic the regulatory action of the inhibitory N-terminal domain of AMPD due to the presence of a zinc ion connecting the N-terminal and C-terminal regions of the enzyme, indicating that the two proteins might physiologically associate to modulate muscle contraction and ammonia production in fast-twitching muscle under strenuous conditions.

Prognostic significance of chronic myocardial injury diagnosed by three different cardiac troponin assays in patients admitted with suspected acute coronary syndrome.

OBJECTIVES: Chronic myocardial injury (CMI) is defined as stable concentrations of cardiac troponin T or I (cTnT or cTnI) above the assay-specific 99th percentile upper reference limit (URL) and signals poor outcome. The clinical implications of diagnosing CMI are unclear. We aimed to assess prevalence and association of CMI with long-term prognosis using three different high-sensitivity cTn (hs-cTn) assays. METHODS: A total of 1,292 hospitalized patients without acute myocardial injury had cTn concentrations quantified by hs-cTn assays by Roche Diagnostics, Abbott Diagnostics and Siemens Healthineers. The median follow-up time was 4.1 years. The prevalence of CMI and hazard ratios for mortality and cardiovascular (CV) events were calculated based on the URL provided by the manufacturers and compared to the prognostic accuracy when lower percentiles of cTn (97.5, 95 or 90), limit of detection or the estimated bioequivalent concentrations between assays were used as cutoff values. RESULTS: There was no major difference in prognostic accuracy between cTnT and cTnI analyzed as continuous variables. The correlation between cTnT and cTnI was high (r=0.724-0.785), but the cTnT assay diagnosed 3.9-4.5 times more patients with having CMI based on the sex-specific URLs (TnT, n=207; TnI Abbott, n=46, TnI Siemens, n=53) and had higher clinical sensitivity and AUC at the URL. CONCLUSIONS: The prevalence of CMI is highly assay-dependent. cTnT and cTnI have similar prognostic accuracy for mortality or CV events when measured as continuous variables. However, a CMI diagnosis according to cTnT has higher prognostic accuracy compared to a CMI diagnosis according to cTnI.

Performance evaluation of a novel high-sensitivity cardiac troponin T assay: analytical and clinical perspectives.

OBJECTIVES: To evaluate the analytical characteristics of a novel high-sensitivity cardiac troponin T (hs-cTnT) test on the automatic light-initiated chemiluminescent assay (LiCA®) system, and validated its diagnostic performance for non-ST-segment elevation myocardial infarction (NSTEMI). METHODS: Studies included an extensive analytical evaluation and established the 99th percentile upper reference limit (URL) from apparently healthy individuals, followed by a diagnostic performance validation for NSTEMI. RESULTS: Sex-specific 99th percentile URLs were 16.0 ng/L (1.7 % CV: coefficient of variation) for men (21-92 years) and 13.4 ng/L (2.0 % CV) for women (23-87 years) in serum, and 30.6 ng/L (0.9 % CV) for men (18-87 years) and 20.2 ng/L (1.4 % CV) for women (18-88 years) in heparin plasma. Detection rates in healthy individuals ranged from 98.9 to 100 %. An excellent agreement was identified between LiCA® and Elecsys® assays with a correlation coefficient of 0.993 and mean bias of -0.7 % (-1.8-0.4 %) across the full measuring range, while the correlation coefficient and overall bias were 0.967 and -1.1 % (-2.5-0.3 %) for the lower levels of cTnT (10-100 ng/L), respectively. At the specific medical decision levels (14.0 and 52.0 ng/L), assay difference was estimated to be <5.0 %. No significant difference was found between these two assays in terms of area under curve (AUC), sensitivity and specificity, negative predictive value (NPV) and positive predictive value (PPV) for the diagnosis of NSTEMI. CONCLUSIONS: LiCA® hs-cTnT is a reliable 3rd-generation (level 4) high-sensitivity assay for detecting cardiac troponin T. The assay is acceptable for practical use in the diagnosis of NSTEMI.

Cardiac troponins and coronary artery calcium score: a systematic review.

An early diagnosis of atherosclerosis, particularly in subclinical status, can play a remarkable role in reducing mortality and morbidity. Because of coronary artery calcification (CAC) nature in radiation exposure, finding biomarkers associated with CAC could be useful in identifying individuals at high risk of CAC score. In this review, we focused on the association of cardiac troponins (hs-cTns) and CAC to achieve insight into the pathophysiology of CAC. In October 2022, we systematically searched Web of Science, Scopus, PubMed, and Embase databases to find human observational studies which have investigated the association of CAC with cardiac troponins. To appraise the included articles, we used the Newcastle Ottawa scale (NOS). Out of 520 records, 10 eligible studies were included. Based on findings from longitudinal studies and cross-sectional analyses, troponin T and I were correlated with occurrence of CAC and its severity. Two of the most important risk factors that affect the correlation between hs-cTns serum levels and CAC were age and gender. The elevation of cardiac troponins may affect the progression of CAC and future cardiovascular diseases. Verifying the association between cardiac troponins and CAC may lead to identify individuals exposed to enhanced risk of cardiovascular disease (CVD) complications and could establish innovative targets for pharmacological therapy.

Wireless continuous single-lead ST-segment monitoring to detect new-onset myocardial injury at the general ward-An exploratory subanalysis.

Patients admitted for acute medical conditions and major noncardiac surgery are at risk of myocardial injury. This is frequently asymptomatic, especially in the context of concomitant pain and analgesics, and detection thus relies on cardiac biomarkers. Continuous single-lead ST-segment monitoring from wireless electrocardiogram (ECG) may enable more timely intervention, but criteria for alerts need to be defined to reduce false alerts. This study aimed to determine optimal ST-deviation thresholds from wireless single-lead ECG for detection of myocardial injury following major abdominal cancer surgery and during acute exacerbation of chronic obstructive pulmonary disease. Patients were monitored with a wireless single-lead ECG patch for up to 4 days and had daily troponin measurements. Single-lead ST-segment deviations of <0.255 mV and/or >0.245 mV (based on previous study comparison with 0.1 mV 12-lead ECG and variation in single-lead ECG) were analyzed for relation to myocardial injury defined as hsTnT elevation of 20-64 ng/L with an absolute change of ≥5 ng/L, or a hsTnT level ≥ 65 ng/L. In total, 528 patients were included for analysis, of which 15.5% had myocardial injury. For corrected ST-thresholds lasting ≥10 and ≥ 20 min, we found specificities of 91% and 94% and sensitivities of 17% and 13% with odds ratios of 2.0 (95% CI: 1.1; 3.9) and 2.4 (95% CI: 1.1; 5.1) for myocardial injury. In conclusion, wireless single-lead ECG monitoring with corrected ST thresholds detected patients developing myocardial injury with specificities >90% and sensitivities <20%, suggesting increased focus on sensitivity improvement.

Serial troponin-T and long-term outcomes in suspected acute coronary syndrome.

BACKGROUND: Long-term prognostic implications of serial high-sensitivity troponin concentrations in subjects with suspected acute coronary syndrome are unknown. METHODS AND RESULTS: Individuals with a first diagnosis of myocardial infarction, unstable angina, observation for suspected myocardial infarction, or chest pain from 2012 through 2019 who underwent two high-sensitivity troponin-T (hsTnT) measurements 1-7 h apart were identified through Danish national registries. Absolute and relative risks for death at days 0-30 and 31-365, stratified for whether subjects had normal or elevated hsTnT concentrations, and whether these concentrations changed by <20%, > 20 to 50%, or >50% in either direction from first to second measurement, were calculated through multivariable logistic regression with average treatment effect modeling. Of the 28 902 individuals included, 2.8% had died at 30 days, whereas 4.9% of those who had survived the first 30 days died between days 31-365. The standardized risk of death was highest among subjects with two elevated hsTnT concentrations (0-30 days: 4.3%, 31-365 days: 7.2%). In this group, mortality was significantly higher in those with a > 20 to 50% or >50% rise from first to second measurement, though only at 30 days. The risk of death was very low in subjects with two normal hsTnT concentrations (0-30 days: 0.1%, 31-365 days: 0.9%) and did not depend on relative or absolute changes between measurements. CONCLUSIONS: Individuals with suspected acute coronary syndrome and two consecutively elevated hsTnT concentrations consistently had the highest risk of death. Mortality was very low in subjects with two normal hsTnT concentrations, irrespective of changes between measurements.

The prognostic significance of early troponin levels in patients undergoing aortic ridge surgery.

Subaortic stenosis is a CHD that can lead to left ventricular hypertrophy, heart failure, and aortic valve damage if left untreated. The gold standard treatment for subaortic stenosis is septal myectomy. However, there is no clear consensus on the surgical margins required for adequate muscle resection. In this retrospective study, we reviewed the records of 83 patients who underwent subaortic stenosis surgery between 2012 and 2020 to investigate the effect of early troponin levels on prognosis. We excluded patients with additional cardiac pathologies, hypertrophic obstructive cardiomyopathy, and valvular aortic stenosis.Troponin levels were recorded in the early post-operative period, and patients were monitored for complications such as ventricular arrhythmia, left ventricular systolic dysfunction, infective endocarditis, and pacemaker implantation. The troponin levels were significantly higher in the patients who had septal myectomy. The degree of myectomy affected the risk of complications in the early post-operative period and recurrence in the later period. However, when the gradient was substantially or completely removed by myectomy, patients experienced significant symptom improvement in the early post-operative period, and their late survival was equivalent to that of healthy individuals of the same age.Our findings suggest that monitoring troponin levels in patients undergoing septal myectomy may be beneficial in predicting the risk of complications. However, further studies are needed to establish the optimal surgical technique and extent of muscle resection required for subaortic stenosis treatment. Our study adds to the existing knowledge of the benefits and risks associated with septal myectomy as a treatment option for subaortic stenosis.

The clinical significance of ischaemia-modified albumin in acute coronary syndrome and hypertension.

BACKGROUND: Early diagnosis of acute coronary syndrome is more and more important because of its mortality and morbidity. Hypertension is one of the pathogenesis of acute coronary syndrome, which often leads to stenosis and ischaemia. Ischaemia-modified albumin is sensitive for the occurrence of ischaemia, which attracted us in the significance of ischaemia-modified albumin in patients with chest pain, especially patients complicated with hypertension. METHODS: In total, 200 patients with acute chest pain were included in the study. According to the diagnostic criteria, patients were divided into acute coronary syndrome group and non-ischaemic chest pain group. Cardiac biomarkers were measured with 30 minutes in emergency department, including cardiac troponin T, creatine kinase MB, and ischaemia-modified albumin. Receiver operating characteristic curve (ROC) analysis was used for the sensitivity and specificity of ischaemia-modified albumin in the early diagnosis of acute coronary syndrome. Comparisons between ischaemia-modified albumin and cardiac Troponin T were done between groups. RESULTS: The demographics in two groups were not significantly different in most aspects. Compared with non-ischaemic chest pain group, serum levels of ischaemia-modified albumin and cardiac Troponin T were significantly higher in acute coronary syndrome group. ROC analysis showed that ischaemia-modified albumin had a good sensitivity and specificity in early diagnosis of acute coronary syndrome. The level of ischaemia-modified albumin in acute coronary syndrome patients with hypertension was higher than that in non-ischaemic chest pain patients. CONCLUSIONS: In patients complained with acute chest pain, the serum measurement of ischaemia-modified albumin is potential valuable for the early diagnosis of acute coronary syndrome, especially combined with ECG. The serum level of ischaemia-modified albumin in acute coronary syndrome patients is significantly associated with hypertension.

Differences in Troponin I and Troponin T Release in High-Performance Athletes Outside of Competition.

Troponin I and troponin T are critical biomarkers for myocardial infarction and damage and are pivotal in cardiological and laboratory diagnostics, including emergency settings. Rapid testing protocols have been developed for urgent care, particularly in emergency outpatient clinics. Studies indicate that strenuous physical activity can cause transient increases in these troponin levels, which are typically considered benign. This research focused on 219 elite athletes from national teams, evaluating their troponin I and T levels as part of routine sports medical exams, independent of competition-related physical stress. The results showed that 9.2% (18 athletes) had elevated troponin I levels above the reporting threshold, while their troponin T levels remained within the normal range. Conversely, only 0.9% (two athletes) had normal troponin I but raised troponin T levels, and 2.3% (five athletes) exhibited increases in both markers. No significant cardiovascular differences were noted between those with elevated troponin levels and those without. This study concludes that elevated troponin I is a common response to the intense physical training endured by high-performance endurance athletes, whereas troponin T elevation does not seem to be directly linked to physical exertion in this group. For cardiac assessments, particularly when ruling out cardiac damage in these athletes, troponin T might be a more reliable indicator than troponin I.

Rapid Exclusion of Acute Myocardial Injury and Infarction With a Single High-Sensitivity Cardiac Troponin T in the Emergency Department: A Multicenter United States Evaluation.

BACKGROUND: There are good data to support using a single high-sensitivity cardiac troponin T (hs-cTnT) below the limit of detection of 5 ng/L to exclude acute myocardial infarction. Per the US Food and Drug Administration, hs-cTnT can only report to the limit of quantitation of 6 ng/L, a threshold for which there are limited data. Our goal was to determine whether a single hs-cTnT below the limit of quantitation of 6 ng/L is a safe strategy to identify patients at low risk for acute myocardial injury and infarction. METHODS: The efficacy (proportion identified as low risk based on baseline hs-cTnT<6 ng/L) of identifying low-risk patients was examined in a multicenter (n=22 sites) US cohort study of emergency department patients undergoing at least 1 hs-cTnT (CV Data Mart Biomarker cohort). We then determined the performance of a single hs-cTnT<6 ng/L (biomarker alone) to exclude acute myocardial injury (subsequent hs-cTnT >99th percentile in those with an initial hs-cTnT<6 ng/L). The clinically intended rule-out strategy combining a nonischemic ECG with a baseline hs-cTnT<6 ng/L was subsequently tested in an adjudicated cohort in which the diagnostic performance for ruling out acute myocardial infarction and safety (myocardial infarction or death at 30 days) were evaluated. RESULTS: A total of 85 610 patients were evaluated in the CV Data Mart Biomarker cohort, among which 24 646 (29%) had a baseline hs-cTnT<6 ng/L. Women were more likely than men to have hs-cTnT<6 ng/L (38% versus 20%, P<0.0001). Among 11 962 patients with baseline hs-cTnT<6 ng/L and serial measurements, only 1.2% developed acute myocardial injury, resulting in a negative predictive value of 98.8% (95% CI, 98.6-99.0) and sensitivity of 99.6% (95% CI, 99.5-99.6). In the adjudicated cohort, a nonischemic ECG with hs-cTnT<6 ng/L identified 33% of patients (610/1849) as low risk and resulted in a negative predictive value and sensitivity of 100% and a 30-day rate of 0.2% for myocardial infarction or death. CONCLUSIONS: A single hs-cTnT below the limit of quantitation of 6 ng/L is a safe and rapid method to identify a substantial number of patients at very low risk for acute myocardial injury and infarction.

High-sensitivity cardiac troponin T in infants exposed to anti-Ro antibodies.

OBJECTIVES: Cardiac involvement in neonatal lupus erythematosis (NLE) can present as myocarditis/endocardial fibroelastosis (EFE). It is unknown whether high-sensitivity cardiac troponin T (hs-cTnT) is useful in identifying subclinical myocardial inflammation in infants exposed prenatally to anti-Ro antibodies. This study reports hs-cTnT levels in infants exposed to anti-Ro antibodies with/without cardiac NLE and reports cardiac MRI (CMR) findings in a subset of these children. METHODS: The study included 45 consecutive infants exposed prenatally to anti-Ro antibodies with (n = 7) or without (n = 38) cardiac NLE, who were seen at the SickKids NLE Clinic between 2012 and 2014. Hs-cTnT levels were measured at least once, and those infants with values of ≥30 ng/l were offered the opportunity to undergo CMR. Descriptive statistics were performed. RESULTS: Of 38 infants without cardiac NLE, 25 had a hs-cTnT level of ≥30 ng/l (including 1 of >113 ng/l); of these, 8 underwent CMR (all without myocarditis/EFE). All 7 infants with cardiac NLE had at least one hs-cTnT level of ≥30 ng/l, but only 2/7 had a level of >113 ng/l; 4/7 infants with cardiac NLE had CMR (all without myocarditis/EFE); 6/7 infants with cardiac NLE had their steroid treatment adjusted based on the trend in their hs-cTnT levels. CONCLUSION: Only 3/45 anti-Ro antibodies-exposed infants had hs-cTnT values outside the reference range reported in healthy infants. None of 12 infants who had CMR had subclinical myocarditis/EFE. Routine measurement of hs-cTnT in every anti-Ro antibody-exposed infant is not indicated. Further studies are needed to define the role of hs-cTnT as a biomarker for cardiac NLE.

Urine High-Sensitive Troponin T-Novel Biomarker of Myocardial Damage in Children.

Background: The use of high-sensitive cardiac troponin T (hsTnT) in urine as a marker of cardiac damage in children has not yet been reported. Elimination of cardiac troponins is dependent on renal function; persistently increased serum hsTnT concentrations were observed among individuals with impaired renal function. The aim of this study was to investigate serum and urine hsTnT levels and its correlation in infants and children younger than 24 months of age after cardiac surgery. Methods: This study was conducted on 90 infants and children under 24 months of age who were divided into three groups. The experimental group consisted of patients with intracardiac surgery of ventricular septal defect (VSD), first control group consisted of infants with extracardiac formation of bidirectional cavopulmonary connection (BCPC), and the second control group consisted of healthy children. Troponin T values ​​were determined in serum and urine at five time points: the first sample was taken on the day before cardiac surgery (measure 0) and the other four samples were taken after the surgery; immediately after (measure 1), on the first (measure 2), third (measure 3), and fifth postoperative day (measure 5). The first morning urine was sampled for determining the troponin T in the control group of healthy infants. Results: A positive correlation between troponin T values in serum and urine was found. Urine hsTnT measured preoperatively in children undergoing BCPC surgery was higher (median 7.3 [IQR 6.6-13.3] ng/L) compared to children undergoing VSD surgery (median 6.5 [IQR 4.4-8.9] ng/L) as well as to healthy population (median 5.5 [IQR 5.1-6.7] ng/L). After logarithmic transformation, there was no statistically significant difference in urine hsTnT concentration between the groups at any point of measurement preoperatively or postoperatively. Statistically significant negative correlation was found between serum and urine hsTnT concentrations and glomerular filtration rate estimated by creatinine clearance. Patients who underwent surgical repair of VSD had significantly higher concentrations of troponin T in serum on the first three postoperative measurements compared to those who had BCPC surgery. Conclusions: According to the results of this study, renal function after cardiac surgery appears to have a major effect on the urinary hsTnT concentrations, and we cannot conclude that this is an appropriate marker for the assessment of postoperative myocardial damage in children. Nevertheless, more research is needed to reach a better understanding of the final elimination of cardiac troponins in children.

Diagnostic and Cost Efficiency of the 0-h/1-h Rule-out and Rule-in Algorithm for Patients With Chest Pain in the Emergency Department.

BACKGROUND: This study investigated the economic impact of the European Society of Cardiology (ESC) clinical practice guideline recommendation of using the 0-h/1-h rule-out and rule-in algorithm with high-sensitivity cardiac troponin assays (0/1-h algorithm) to triage patients presenting with chest pain.Methods and Results: This post hoc cost-effectiveness evaluation (DROP-ACS; UMIN000030668) used deidentified electronic medical records from health insurance claims from 2 diagnostic centers in Japan. A cost-effectiveness analysis was conducted with 472 patients with care provided following the 0/1-h algorithm (Hospital A) and 427 patients following point-of-care testing (Hospital B). The clinical outcome of interest was all-cause mortality or subsequent myocardial infarction within 30 days of the index presentation. The sensitivity and specificity for the clinical outcome were 100% (95% confidence interval [CI] 91.1-100%) and 95.0% (95% CI 94.3-95.0%), respectively, in Hospital A and 92.9% (95% CI 69.6-98.7%) and 89.8% (95% CI 89.0-90.0%), respectively, in Hospital B. If the diagnostic accuracy of the 0/1-h algorithm was implemented in Hospital B, it is expected that the number of urgent (<24-h) coronary angiograms would decrease by 50%. Incorporating this assumption, implementing the 0/1-h algorithm could potentially reduce medical costs by JPY4,033,874 (95% CI JPY3,440,346-4,627,402) in Hospital B (JPY9,447 per patient; 95% CI JPY 8,057-10,837 per patient). CONCLUSIONS: The ESC 0/1-h algorithm was efficient for risk stratification and for reducing medical costs.

Cardiac troponin measurement at the point of care: educational recommendations on analytical and clinical aspects by the IFCC Committee on Clinical Applications of Cardiac Bio-Markers (IFCC C-CB).

The International Federation of Clinical Chemistry and Laboarator Medicine (IFCC) Committee on Clinical Applications of Cardiac Bio-Markers (C-CB) has provided evidence-based educational resources to aid and improve the understanding of important analytical and clinical aspects of cardiac biomarkers. The present IFCC C-CB educational report focuses on recommendations for appropriate use, analytical performance, and gaps in clinical studies related to the use of cardiac troponin (cTn) by point of care (POC) measurement, often referred to as a point of care testing (POCT). The use of high-sensitivity (hs)-cTn POC devices in accelerated diagnostic protocols used in emergency departments or outpatient clinics investigating acute coronary syndrome has the potential for improved efficacy, reduction of length of stay and reduced costs in the health care system. POCT workflow integration includes location of the instrument, assignment of collection and testing responsibility to (non-lab) staff, instrument maintenance, in-service and recurrent training, quality control, proficiency assessments, discrepant result trapping, and troubleshooting and inventory management.

Higher troponin T serum concentrations in hospital patients without diagnosed cardiac diseases compared to a population-based cohort.

OBJECTIVES: Upper reference limits of high-sensitivity cardiac troponin T (hs-cTnT) are derived from healthy, population-based cohorts, and are frequently exceeded in hospitalized patients. In this study we aim to systematically examine the differences between in-hospital patients with no diagnosed cardiac diseases and a population-based cohort. METHODS: Retrospective analyses were performed in two independent cohorts. We included 5,652 participants of the prospective population-based LIFE cohort as well as 9,300 patients having been treated at our hospital between 2014 and 2021. In both cohorts, subjects with diagnosed or suspected cardiac diseases were excluded. We used Spearman's rank correlation for correlation analyses of hs-cTnT serum concentrations and age. Sex- and age-adjusted 99th percentiles for hs-cTnT in subjects with preserved renal function were obtained in both cohorts. RESULTS: In both cohorts, hs-cTnT serum concentrations positively correlated with age. Male sex was associated with higher hs-cTnT serum concentrations. Persons treated in hospital showed significantly higher hs-cTnT concentrations in females and males aged above 50. While in the population-based cohort only 99th percentile hs-cTnT results of females aged above 70 and males aged above 60 years exceeded the assay's upper reference limit, the 99th percentiles of in-hospital females over 40 years and males of all age groups exceeded this threshold. CONCLUSIONS: Besides age and sex, hospitalization per se is correlated with higher serum concentrations of hs-cTnT in most age groups. Our results indicate, that unconditionally applying current hs-cTnT cut-offs to inpatients might overestimate myocardial infarction and potentially lead to overdiagnosis.

Cardiac Troponin T and NT-proBNP for Prediction of 30-Day Readmission or Death in Patients with Acute Dyspnea: Data from the Akershus Cardiac Examination 2 Study.

INTRODUCTION: N-terminal pro-B-type natriuretic peptide (NT-proBNP) and cardiac troponin T (cTnT) measurements are recommended in patients with acute dyspnea. We aimed to assess the prognostic merit of cTnT compared to NT-proBNP for 30-day readmission or death in patients hospitalized with acute dyspnea. METHODS: We measured cTnT and NT-proBNP within 24 h in 314 patients hospitalized with acute dyspnea and adjudicated the cause of the index admission. Time to first event of readmission or death ≤30 days after hospital discharge was recorded, and cTnT and NT-proBNP measurements were compared head-to-head. RESULTS: Patients who died (12/314) or were readmitted (71/314) within 30 days had higher cTnT concentrations (median: 32.6, Q1-Q3: 18.4-74.2 ng/L vs. median: 19.4, Q1-Q3: 8.4-36.1 ng/L; p for comparison <0.001) and NT-proBNP concentrations (median: 1,753.6, Q1-Q3: 464.2-6,862.0 ng/L vs. median 984, Q1-Q3 201-3,600 ng/L; for comparison p = 0.027) compared to patients who survived and were not readmitted. cTnT concentrations were associated with readmission or death within 30 days after discharge both in the total cohort (adjusted hazard ratio [aHR]: 1.64, 95% confidence interval [CI]: 1.30-2.05) and in patients with heart failure (HF) (aHR: 1.58, 95% CI: 1.14-2.18). In contrast, NT-proBNP concentrations were not associated with short-term events, neither in the total cohort (aHR: 1.10, 95% CI: 0.94-1.30) nor in patients with adjudicated HF (aHR: 1.06, 95% CI: 0.80-1.40). CONCLUSION: cTnT concentrations are associated with 30-day readmission or death in patients hospitalized with acute dyspnea, as well as in patients adjudicated HF.

The low-dose colchicine in patients after non-CABG cardiac surgery: a randomized controlled trial.

BACKGROUND: Recent high-quality trials have shown that the anti-inflammatory effects of colchicine reduce the risk of cardiovascular events in patients suffering post-myocardial infarction and chronic coronary disease. The effect of colchicine in patients undergoing non-coronary artery bypass grafting (non-CABG) with cardiopulmonary bypass remains unclear. We aim to evaluate the effect of colchicine on myocardial protection in patients who underwent non-CABG cardiac surgery. METHOD: Patients were randomly assigned to colchicine or placebo groups starting 72 h before scheduled cardiac surgery and for 5 days thereafter (0.5 mg daily).The primary outcome was the level of cardiac troponin T (cTnT) at postoperative 48 h. The secondary outcomes included troponin I (cTnI) and creatine kinase-MB (CK-MB), inflammatory biomarkers (procalcitonin and interleukin-6, etc.), and adverse events (30-day mortality, stroke, ECMO and IABP use, etc.). RESULTS: A total of 132 patients underwent non-CAGB cardiac surgery, 11were excluded because of diarrhea (n = 6) and long aortic cross-clamp time > 2 h (n = 5), 59 were assigned to the colchicine group and 62 to the placebo group. Compared with the placebo group, cTnT (median: 0.3 µg/L, IQR 0.2-0.4 µg/L vs. median: 0.4 µg/L, IQR 0.3-0.6 µg/L, P < 0.01), cardiac troponin I (median: 0.9 ng/ml, IQR 0.4-1.7 ng/ml vs. median: 1.3 ng/ml, IQR 0.6-2.3 ng/ml, P = 0.02), CK-MB (median: 1.9 ng/ml, IQR 0.7-3.2 ng/ml vs. median: 4.4 ng/ml, IQR 1.5-8.2 ng/ml, P < 0.01), and interleukin-6 (median: 73.5 pg/ml, IQR 49.6-125.8 pg/ml vs. median: 101 pg/ml, IQR 57.5-164.7 pg/ml, P = 0.048) were significantly reduced in colchicine group at postoperative 48 h. For safety evaluation, the colchicine (n = 65) significantly decreased post-pericardiotomy syndrome (3.08% vs. 17.7%, P < 0.01) and increased the rate of diarrhea (9.23% vs. 0, P = 0.01) compared with the placebo group (n = 62). No significant difference was observed in other adverse events between the two groups. CONCLUSION: A short perioperative course of low-dose colchicine was effective to attenuate the postoperative biomarkers of myocardial injury and inflammation, and to decrease the postoperative syndrome compared with the placebo. Trial registration ChiCTR2000040129. Registered 22nd Nov. 2020. This trial was registered before the first participant was enrolled. http://www.chictr.org.cn/showproj.aspx?proj=64370 .