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.

Prospective Multicenter Screening With High-Sensitivity Cardiac Troponin T for Wild-Type Transthyretin Cardiac Amyloidosis in Outpatient and Community-Based Settings.

BACKGROUND: High-sensitivity cardiac troponin T (hs-cTnT) was proposed as a simple and useful diagnostic tool for cardiac amyloidosis (CA). We performed exploratory systemic screening using hs-cTnT to detect wild-type transthyretin CA (ATTRwt-CA) in outpatient and community-based settings. METHODS AND RESULTS: This study was a prospective multicenter study including 8 internal medicine clinics in Kochi Prefecture, Japan. Consecutive individuals aged ≥70 years who visited those clinics as outpatients were enrolled. Patients with a prior diagnosis of CA or a history of heart failure hospitalization were excluded. We measured hs-cTnT levels in the enrolled individuals at each clinic, and those with elevated hs-cTnT levels (≥0.03ng/mL) received further detailed examination, including remeasurement of hs-cTnT. The diagnosis of ATTRwt-CA was confirmed by biopsy-proven transthyretin. Of 1,141 individuals enrolled in the study, 55 (4.8%) had elevated hs-cTnT levels. Of the 33 patients who underwent further examination, 22 had elevated hs-cTnT levels at remeasurement. Finally, 2 men were diagnosed with ATTRwt-CA. The prevalence of ATTRwt-CA was 9.1% (2/22) among patients with elevated hs-cTnT levels at two examinations, and at least 0.18% (2/1,141) in the whole study population. CONCLUSIONS: Measurement of hs-cTnT will help to screen for patients with undiagnosed ATTRwt-CA in primary care practice.

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.

High-sensitive troponin T, suPAR and Beta-2-microglobulin changes in concentration during hemodialysis.

Hemodialysis (HD) patients are at high risk of cardiovascular disease and death. Reliable biomarkers for risk stratification and detection of acute myocardial infarction (AMI) are therefore pivotal. Cardiac troponins (cTn) are the preferred biomarkers for AMI. It remains unclear, if cTn concentrations changes as a consequence of HD treatment itself during dialysis. In this study, cTn was compared with soluble urokinase plasminogen activator receptor (suPAR) and Beta-2-microglobulin (B2M). We performed a prospective study including 17 HD patients measuring high-sensitive cardiac troponin t (hs-cTnT), suPAR and B2M before and after a dialysis session and verified the results in a random subgroup of eight patients from the group by repeating their measurements before and after a dialysis session 15 weeks later. Biomarker concentrations after dialysis were adjusted according to hemodilution or concentration according to the hemoglobin concentration. The average hs-cTnT concentration decreased significantly by -9.9% after dialysis (95% CI: -13.6% to -6.2%). The average (paired) difference were - 6.7 ng/L (p = 0.0104) after dialysis comparing 25 HD treatment occasions. SuPAR was not significantly influenced by dialysis. B2M decreased by -58% after HD as an expected result from the molecular size of the biomarker. The hs-cTnT in average decreased by -9.9% after dialysis. This is a diagnostic challenge since the current guidelines suggest a 20% change in hs-cTnT in patients with acute myocardial infarction. Larger prospective studies investigating the different factors influencing hs-cTnT after HD are warranted. Adjusting biomarker concentrations according to hemodilution or concentration using the hemoglobin concentration, should be considered in future studies to determine more exact changes in concentrations of cTnT and other relevant biomarkers.

Effect of dexmedetomidine on postoperative high-sensitivity cardiac troponin T in patients undergoing video-assisted thoracoscopic surgery: a prospective, randomised controlled trial.

BACKGROUND: One-lung ventilation and intrathoracic operations during thoracoscopic surgery often result in intraoperative hypoxaemia and haemodynamic fluctuations, resulting in perioperative myocardial injury. Dexmedetomidine, an alpha-2 (α-2) agonist, has demonstrated myocardial protection. We hypothesize that the routine intravenous administration of dexmedetomidine could reduce the extent of myocardial injury during video-assisted thoracoscopic surgery (VATS). METHODS: The study included patients aged ≥ 45 years, classified as American Society of Anesthesiologists physical status I-III, who underwent general anesthesia for video-assisted thoracoscopic surgery. The patients were randomly assigned to either the intervention group, receiving general anesthesia with dexmedetomidine, or the control group, receiving general anesthesia without dexmedetomidine. Patients in the intervention group received a loading dose of dexmedetomidine (0.5 µg·kg-1) before anesthesia induction, followed by a continuous infusion (0.5 µg·kg-1·h-1) until the completion of the surgery. Placebos (saline) were administered for the control group to match the treatment. The primary outcome assessed was the high-sensitivity cardiac troponin T on postoperative day 1. Additionally, the incidence of myocardial injury after noncardiac surgery (MINS) was noted. RESULTS: A total of 110 participants completed this study. The median [interquartile range (IQR)] concentration of hs-cTnT on postoperative day 1 was lower in the intervention group compared with the control group (7 [6-9] vs. 8 [7-11] pg·ml-1; difference in medians,1 pg·ml-1; 95% confidence interval [CI], 0 to 2; P = 0.005). Similarly, on postoperative day 3, the median [IQR] concentration of hs-cTnT in the intervention group was also lower than that in the control group (6 [5-7] vs. 7 [6-9]; difference in medians,1 pg·ml-1; 95%CI, 0 to 2; P = 0.011). Although the incidence of MINS was not statistically significant (the intervention group vs. the control group, 3.8% vs. 9.1%, P = 0.465), there was a decreasing trend in the incidence of MINS in the intervention group. CONCLUSION: The administration of perioperative dexmedetomidine in patients ≥ 45 years undergoing video-assisted thoracoscopic surgery could lower the release of postoperative hs-cTnT without reducing incidence of myocardial injury. TRIAL REGISTRATION: chictr.org.cn (ChiCTR2200063193); prospectively registered 1 September 2022.

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.

Impregnation of two-dimensional manganese dioxide nanosheets with 5-carboxyfluorescein as an immunoassay platform for sensitive detection of cardiac troponin T.

A novel immunoassay platform is presented utilizing a cardiac troponin T antibody (Ab-cTnT) labelled with 5-carboxyfluorescein (5-FAM) integrated into a two-dimensional (2D) manganese dioxide nanosheet (MnO2 NS) matrix. This strategy enables a turn-on response towards cTnT antigen within a mere 10-min incubation period, boasting an impressive lower detection limit of 0.038 ng/mL. Crucially, our probe demonstrates exceptional selectivity amidst the presence of coexisting biomolecules and ions, ensuring precise detection of cTnT. Moreover, the developed platform showcases promising utility in sensing cTnT from spiked human serum samples, yielding satisfactory recovery percentages ranging from 82 to 105%. Additionally, we introduce and easy-to-use and cost-effective test strip for point-of-care detection of cTnT, further enhancing accessibility to critical cardiovascular diagnostics.

Clinical Efficacy and Safety Analysis of Recombinant Human Brain Natriuretic Peptide Combined with Sacubitril/Valsartan in the Sequential Treatment of Senile Patients with Acute Heart Failure.

This study aims to evaluate the comparative efficacy and safety of the combination of recombinant human brain natriuretic peptide (rhBNP) and sacubitril/valsartan in the sequential treatment of senile patients with acute heart failure (AHF).The study objects were a total of 136 senile patients over 60 years old with AHF admitted to the Department of Cardiology of Anji County People's Hospital of Huzhou from August 2022 to August 2023. Using the envelope method, the patients were divided into three groups: the standard treatment group (45 patients who underwent hydragogue, digoxin, valsartan, and beta-blockers), the rhBNP group (46 patients were performed with basic treatment for AHF combined with rhBNP), and the sequential treatment group (45 patients received the basic treatment for AHF combined with rhBNP followed by sacubitril/valsartan). The clinical effects, cardiac function, safety, and prognosis among the three groups were compared.In the sequential treatment group, the duration of clinical symptom remission, the duration of hospitalization, and the improvement rate of New York Heart Association classification at discharge were (2.27 ± 0.76) days, (6.99 ± 1.96) days, and 93.3%, which were better than those in the rhBNP group ([2.58 ± 0.94] days, [7.43 ± 2.78] days, and 78.3%) and the standard treatment group ([2.89 ± 0.71] days, [8.82 ± 2.89] days, and 71.1%); the P value among all groups was lower than 0.05. In terms of cardiac function and myocardial injury, the sequential treatment group was superior to the standard treatment group and rhBNP group. The incidence of adverse reactions in the standard treatment group, the rhBNP group, and the sequential treatment group was 37.8%, 34.8%, and 26.7%, respectively, P = 0.510. In the sequential treatment group, the rate of heart failure readmitted within 6 months after discharge was 28.9% and no death occurred, which was lower than those in the rhBNP (34.8%) and the standard treatment group (35.6%).Sequential treatment with rhBNP and sacubitril/valsartan could significantly improve the clinical symptoms of elderly patients with AHF, enhance cardiac function, and reduce myocardial damage, which could also improve the prognosis.

Imaging and Biomarkers: The Assesment of Pulmonary Embolism Risk and Early Mortality.

Background and Objectives: Pulmonary embolism (PE) incidence has been increasing in the last 10 years. Computed thoracic pulmonary angiography (CTPA) had a major role in PE diagnosis and prognosis. The main purpose of this study was as follows: the prognostic value of a CTPA parameter, pulmonary artery obstruction index (PAOI), in PE risk assessment and the predictive accuracy of biomarkers, D-dimer and cardiac Troponin T (c-TnT), in 7-day mortality. A second objective of the research was to investigate the relationship between imaging by PAOI and these biomarkers in different etiologies of PE. Materials and Methods: This study comprised 109 patients with PE, hospitalized and treated between February 2021 and August 2022. They had different etiologies of PE: deep vein thrombosis (DVT); persistent atrial fibrillation (AF); chronic obstructive pulmonary disease (COPD) exacerbation; COVID-19; and cancers. The investigations were as follows: clinical examination; D-dimer testing, as a mandatory method for PE suspicion (values ≥500 µg/L were highly suggestive for PE); c-TnT, as a marker of myocardial injury (values ≥14 ng/L were abnormal); CTPA, with right ventricle dysfunction (RVD) signs and PAOI. Treatments were according to PE risk: systemic thrombolysis in high-risk PE; low weight molecular heparins (LWMH) in high-risk PE, after systemic thrombolysis or from the beginning, when systemic thrombolysis was contraindicated; and direct oral anticoagulants (DOAC) in low- and intermediate-risk PE. Results: PAOI had a high predictive accuracy for high-risk PE (area under curve, AUC = 0.993). D-dimer and cTnT had a statistically significant relationship with 7-day mortality for the entire sample, p < 0.001, and for AF, p = 0.0036; COVID-19, p = 0.003; and cancer patients, p = 0.005. PAOI had statistical significance for 7-day mortality only in COVID-19, p = 0.045, and cancer patients, p = 0.038. The relationship PAOI-D-dimer and PAOI-c-TnT had very strong statistical correlation for the entire sample and for DVT, AF, COPD, and COVID-19 subgroups (Rho = 0.815-0.982). Conclusions: PAOI was an important tool for PE risk assessment. D-dimer and c-TnT were valuable predictors for 7-day mortality in PE. PAOI (imaging parameter for PE extent) and D-dimer (biomarker for PE severity) as well as PAOI and c-TnT (biomarker for myocardial injury) were strongly correlated for the entire PE sample and for DVT, AF, COPD, and COVID-19 patients.

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.

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.

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 use of high-sensitivity cardiac troponin T and creatinine kinase-MB as a prognostic markers in patients with acute myocardial infarction and chronic kidney disease.

Background: High-sensitivity cardiac troponin T (hs-cTnT) and creatine kinase (CK)-MB are the most commonly used biomarkers for the diagnosis and prognosis of acute myocardial infarction (AMI). Chronic kidney disease (CKD) often leads to elevated hs-cTnT levels in non-AMI patients. However, studies comparing the prognostic value of both hs-cTnT and CK-MB in patients with AMI and CKD are lacking.Methods: We conducted a retrospective study on AMI patients diagnosed between January 2015 and October 2020. Patients were categorized based on renal function as normal or CKD. Peak hs-cTnT and CK-MB levels during hospitalization were collected, and their diagnostic value was evaluated using receiver operating characteristic (ROC) curves. The impact on in-hospital mortality was analyzed using multivariate logistic regression. The relationship between the hs-cTnT/CK-MB ratio and in-hospital death was examined using a restricted cubic spline (RCS) curve.Results: The study included 5022 AMI patients, of whom 797 (15.9%) had CKD. The AUCs of Hs-cTnT and CK-MB were higher in the CKD group [0.842 (95% CI: 0.789-0.894) and 0.821 (95% CI: 0.760-0.882)] than in the normal renal function group [0.695 (95% CI: 0.604-0.790) and 0.708 (95% CI: 0.624-0.793)]. After full adjustment for all risk factors, hs-cTnT (OR, 2.82; 95% CI, 1.03-9.86; p = 0.038) and CK-MB (OR, 4.91; 95% CI, 1.54-14.68; p = 0.007) above the cutoff values were independent predictors of in-hospital mortality in patients with CKD. However, in patients with normal renal function, only CK-MB above the cutoff (OR, 2.45; 95% CI, 1.02-8.24; p = 0.046) was a predictor of in-hospital mortality, whereas hs-cTnT was not. There was an inverted V-shaped relationship between the hs-cTnT/CK-MB ratio and in-hospital mortality, with an inflection point of 19.61. The ratio within the second quartile (9.63-19.6) was an independent predictor of in-hospital mortality in patients with CKD (OR 5.3, 95% CI 1.66-16.86, p = 0.005).Conclusions: Hs-cTnT independently predicted in-hospital mortality in AMI patients with CKD, whereas its predictive value was not observed in patients with normal renal function. CK-MB was an independent predictor of in-hospital mortality regardless of renal function. Moreover, the hs-cTnT/CK-MB ratio may aid in risk stratification of AMI patients with CKD.

Myocardial injury defined as elevated high-sensitivity cardiac troponin T is associated with higher mortality in patients seeking care at emergency departments with acute dyspnea.

BACKGROUND: Elevated levels of cardiac troponin T has been observed in patients seeking care at the emergency department (ED) presenting with chest pain but without myocardial infarction (MI). The clinical importance of this observation remains, however, still unclear. Our main aim was to study the role of cardiac troponin T in patients admitted to the emergency department with acute dyspnea, a group of patients with a high cardiovascular comorbidity, but no primary acute MI. POPULATION AND METHODS: Patients from the age of 18 seeking care at the ED for dyspnea, without an acute cardiac syndrome, and with a recorded assessment of high-sensitivity cardiac troponin T (hs-cTnT), were included (n = 1001). Patients were categorized into 3 groups by hs-cTnT level, i.e. <15, 15-100 and > 100 µg/l. Cox regression with Hazard Ratios (HRs) and 95% Confidence Intervals (CI) for 3-months mortality was performed, with adjustment for sex, age, respiratory frequency, saturation, CHF, renal disease, and BMI. RESULTS: Fully adjusted HRs (95% CI) for 3-month mortality, with hs-cTnT < 15 µg/l as reference level, showed for hs-cTnT 15-100 a HR of 3.682 (1.729-7.844), and for hs-cTnT > 100 a HR of 10.523 (4.465-24.803). CONCLUSION: Elevated hs-cTnT seems to be a relevant marker of poor prognosis in patients with acute dyspnea without MI and warrants further validation and clinical testing.

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.

High-Sensitivity Cardiac Troponin I and T Kinetics Differ following Coronary Bypass Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: Cardiac troponin I and T are both used for diagnosing myocardial infarction (MI) after coronary artery bypass grafting (CABG), also known as type 5 MI (MI-5). Different MI-5 definitions have been formulated, using multiples of the 99th percentile upper reference limit (10×, 35×, or 70× URL), with or without supporting evidence. These definitions are arbitrarily chosen based on conventional assays and do not differentiate between troponin I and T. We therefore investigated the kinetics of high-sensitivity cardiac troponin I (hs-cTnI) and T (hs-cTnT) following CABG. METHODS: A systematic search was applied to MEDLINE and EMBASE databases including the search terms "coronary artery bypass grafting" AND "high-sensitivity cardiac troponin." Studies reporting hs-cTnI or hs-cTnT on at least 2 different time points were included. Troponin concentrations were extracted and normalized to the assay-specific URL. RESULTS: For hs-cTnI and hs-cTnT, 17 (n = 1661 patients) and 15 studies (n = 2646 patients) were included, respectively. Preoperative hs-cTnI was 6.1× URL (95% confidence intervals: 4.9-7.2) and hs-cTnT 1.2× URL (0.9-1.4). Mean peak was reached 6-8 h postoperatively (126× URL, 99-153 and 45× URL, 29-61, respectively). Subanalysis of hs-cTnI illustrated assay-specific peak heights and kinetics, while subanalysis of surgical strategies revealed 3-fold higher hs-cTnI than hs-cTnT for on-pump CABG and 5-fold for off-pump CABG. CONCLUSION: Postoperative hs-cTnI and hs-cTnT following CABG surpass most current diagnostic cutoff values. hs-cTnI was almost 3-fold higher than hs-cTnT, and appeared to be highly dependent on the assay used and surgical strategy. There is a need for assay-specific hs-cTnI and hs-cTnT cutoff values for accurate, timely identification of MI-5.

Upper Reference Limits for High-Sensitivity Cardiac Troponin T and N-Terminal Fragment of the Prohormone Brain Natriuretic Peptide in Patients With CKD.

RATIONALE & OBJECTIVE: The utility of conventional upper reference limits (URL) for N-terminal pro-brain natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hsTnT) in chronic kidney disease (CKD) remains debated. We analyzed the distribution of hsTnT and NT-proBNP in people with CKD in ambulatory settings to examine the diagnostic value of conventional URL in this population. STUDY DESIGN: Observational study. SETTING & PARTICIPANTS: We studied participants of the Chronic Renal Insufficiency Cohort (CRIC) with CKD and no self-reported history of cardiovascular disease. EXPOSURE: Estimated glomerular filtration rate (eGFR). OUTCOME: NT-proBNP and hsTnT at baseline. ANALYTICAL APPROACH: We described the proportion of participants above the conventional URL for NT-proBNP (125pg/mL) and hsTnT (14ng/L) overall and by eGFR. We then estimated 99th percentile URL for NT-proBNP and hsTnT. Using quantile regression of the 99th percentile, we modeled the association of eGFR with NT-proBNP and hsTnT. RESULTS: Among 2,312 CKD participants, 40% and 43% had levels of NT-proBNP and hsTnT above the conventional URL, respectively. In those with eGFR <30mL/min/1.73m2, 71% and 68% of participants had concentrations of NT-proBNP and hsTnT above the conventional URL, respectively. Among all CKD participants, the 99th percentile for NT-proBNP was 3,592 (95% CI, 2,470-4,849) pg/mL and for hsTnT it was 126 (95% CI, 100-144) ng/L. Each 15mL/min/1.73m2 decrement in eGFR was associated with a ~40% higher threshold for the 99th percentile of NT-proBNP (1.43 [95% CI, 1.21-1.69]) and hsTnT (1.45 [95% CI, 1.31-1.60]). LIMITATIONS: Study included ambulatory patients, and we could not test the accuracy of the URL of NT-proBNP and hsTnT in the acute care setting. CONCLUSIONS: In this ambulatory CKD population with no self-reported history of cardiovascular disease, a range of 40%-88% of participants had concentrations of NT-proBNP and hsTnT above the conventional URL, depending on eGFR strata. Developing eGFR-specific thresholds for these commonly used cardiac biomarkers in the setting of CKD may improve their utility for evaluation of suspected heart failure and myocardial infarction.

The bidirectional association of C-peptide with cardiovascular risk in nondiabetic adults and patients with newly diagnosed type 2 diabetes mellitus: a retrospective cohort study.

BACKGROUND: Recent literature reported the biological role of C-peptide, but this role is still controversial and unclear. The primary aim of this study was to investigate associations between C-peptide and cardiovascular biomarkers as well as events. METHODS: A total of 55636 participants who had a health examination from 2017 to 2021 were included. Of them, 6727 participants visited the hospital at least twice. Cardiovascular biomarkers like high-sensitivity C-reactive protein (hs-CRP) and high-sensitivity cardiac troponin T (hs-cTnT) were measured and their relationships with fasting C-peptide were evaluated for all participants. Cardiovascular events were obtained during the last visit and their associations with C-peptide were evaluated for those participants who visited the hospital at least twice. RESULTS: Among the included participants, 11.1% had a previous type 2 diabetes mellitus (T2DM). In the participants without previous T2DM, the relationships between fasting C-peptide and hs-CRP and hs-cTnT were negative if the value of fasting C-peptide was < 1.4 ng/mL and positive if the value was ≥ 1.4 ng/mL. These relationships remained significant after adjusting for hemoglobin A1c, insulin resistance index, and its interaction with C-peptide, even if the participants were stratified by glucose metabolism status or levels of insulin resistance index. Hazard ratios of cardiovascular events were first decreased and then increased with the increasing of baseline C-peptide levels, though these associations became unsignificant using the multivariate Cox regression model. Unlike the participants without previous T2DM, the associations of C-peptide with cardiovascular biomarkers and events were not significant in the patients with previous T2DM. CONCLUSIONS: The associations of C-peptide with cardiovascular biomarkers and events were different between the participants without previous T2DM and those with previous T2DM. The effect of C-peptide on cardiovascular risk may be bidirectional, play a benefit role at a low level, and play a harmful role at a high level in the nondiabetic adults and the patients with newly diagnosed T2DM.