Rapid diagnosis of acute myocardial infarction through integrated microfluidic chips for detection of characteristic targets

Myoglobin (Myo), creatine kinase-MB (CKMB), and cardiac troponin I (cTnI) are crucial biomarkers for diagnosing acute myocardial infarction (AMI) The accurate and rapid detection of these three targets can greatly improve the prognosis of AMI patients. Herein, this study developed a microfluidic immunofluorescence method that can detect all three targets in 10-15 min. Ultrasonic atomization and spray technology are used to modify the surface of the injection-molded microfluidic chip (MFC), which effectively solves the problem of biological cross-linking and antibody immobilization on the MFC surface. In addition, it improves the hydrophilicity of the chip surface, thus enhancing fluid self-driving effect. The linear response towards Myo, CKMB and cTnI range from 5 ng/mL to 500 ng/mL, 1 ng/mL to 70 ng/mL, and 0.05 ng/mL to 30 ng/mL, respectively. The intra-batch precision is ≤ 10%, and the inter-batch precision is ≤ 15%. Furthermore, this method shows good consistency compared with the BECKMAN ACCESS2 chemiluminescent immunoanalyzer. The present work provides an AMI diagnostic method with high sensitivity, good repeatability, high accuracy and simple operation, which can satisfy the needs of clinical diagnosis, and shows promising application prospects.

Clinical relevance and advances in detection of translational biomarker cardiac troponin

Cardiovascular diseases (CVD) are a range of diseases, pointing the functional hindrances in the heart and blood vessels of the human system that contributes to 48.6 % of the world's adult death rate. The diagnosis of CVD relies upon the Electro Cardio Gram (ECG) and detection of muscle markers such as troponins. Among the cardiac trio, Cardiac Troponin I (cTnI) weighing 23 KiloDalton (kDa) is a sorted biomarker for CVD. cTnI remains high in the blood after 1-2 weeks of myocardial damage. Testing of cTnI in CVD patients aids in diagnosis and risk stratification of the disease. Different determination systems including optical, electrochemical, and acoustic have been put forward for monitoring the cTnI which are Point of Care (POC) that promotes simple and sensitive detection of cTnI. The modern era has paved way to high-sensitivity Troponin I (hscTnI) devices that can detect up to 0.01 ng/ml in human blood/plasma/serum. Yet, the practice of hscTnI is impracticable due to cost inefficiency. Development of new hscTnI devices with minimal investment and maximal detection range will meet the global requirement. This review gives an over view on different detection systems of cardiac troponin I which stands as a translational detection molecule for CVDs.

Copeptin for the differentiation of type 1 versus type 2 myocardial infarction or myocardial injury

BACKGROUND

The rapid and reliable differentiation of myocardial infarction (MI) due to atherothrombosis (T1MI) from MI due to supply-demand mismatch (T2MI) or acute myocardial injury is of major clinical relevance due to very different treatments, but still a major unmet clinical need. This study aimed to investigate whether copeptin, a stress hormone produced in the hypothalamus, helps to differentiate between T1MI versus T2MI or injury.

METHODS

In a retrospective analysis, 1271 unselected consecutive patients presenting with symptoms suggestive of MI to the emergency department were evaluated. Patients diagnosed with ST-elevation MI were excluded. All patients with elevated cardiac troponin I (cTnI) concentration possibly indicating MI were classified into T1MI, T2MI, or acute myocardial injury using detailed clinical assessment and coronary imaging. Copeptin plasma concentration was measured in a blinded fashion. A multicenter diagnostic study with central adjudication of the final diagnosis served as external validation cohort (n = 1390).

RESULTS

Among 1161 patients, 154 patients had increased cTnI concentration. Of these, 78 patients (51%) were classified as T1MI and 76 (49%) as T2MI or myocardial injury. Patients with T2MI or myocardial injury had significantly higher copeptin plasma concentration between patients versus T1MI (21,4 pmol/l versus 8,1 pmol/l, p = 0,001). A multivariable regression analysis revealed that higher concentrations of copeptin and C-reactive protein, higher heart rate at presentation and lower frequency of smoking remained significantly associated with T2MI and myocardial injury. Findings were largely confirmed in the external validation cohort.

CONCLUSION

In patients without ST-segment elevation, copeptin concentration was higher in T2MI and myocardial Injury versus T1MI and may help in their differential diagnosis.

The effects of a multi-day cross-country mountain bike race on myocardial function, stress, inflammation and cardiac biomarkers in amateur master athletes

This study aimed to examine the effects of a multi-day mountain bike race on amateur master athlete cyclists (AMA). AMA (50±5 years) completed 2 stages of a mountain bike race. Six weeks before racing, echocardiography, blood and maximal cardiopulmonary exercise tests (CPET) were performed. One hour after completion of each race stage, echocardiography measurements were taken and blood was sampled for stress, inflammatory and cardiac biomarkers. Main outcomes of the CPET were maximal oxygen consumption (VO2max) 50.7±6.5 ml/kg/min; maximal power 328±45 Watt and ventilatory threshold of 86%VO2max. Participants completed 95.7km with an elevation of 1650m on the first day, and 92.5km with an elevation of 1410m on the second day, with completion times of 357±42 and 390 ±43 minutes, respectively. After racing, increases in Creatine Phosphokinase and C-reactive protein (3-6 fold) (p<0.001), Troponin I (4-fold) (p<0.001) and N-terminal pro-brain natriuretic peptide (NT-Pro BNP) (4-7-fold) (p<0.001) were noted, with a reduction in the myocardial global work index of 17-24% (p<0.001). No correlations were found between Troponin I or NT-Pro BNP and myocardial global work index. Highly aerobically fit AMA participating in demanding endurance events demonstrated elevated stress, inflammatory, muscle damage and cardiac biomarkers. However, these changes did not significantly correlate with altered cardiac function. In addition, consecutive days of demanding prolonged cycling exercise did not have cumulative effects on the measured myocardial parameters.

[Risk factors for acute respiratory distress syndrome in patients with traumatic hemorrhagic shock]

OBJECTIVE

To investigate the risk factors of acute respiratory distress syndrome (ARDS) after traumatic hemorrhagic shock.

METHODS

This was a retrospective cohort study of 314 patients with traumatic hemorrhagic shock at Trauma Medicine Center, Peking University People's Hospital from December 2012 to August 2021, including 152 male patients and 162 female patients, with a median age of 63.00 (49.75-82.00) years. The demographic data, past medical history, injury assessment, vital signs, laboratory examination and other indicators of these patients during hospitalization were recorded. These patients were divided into two groups, ARDS group (n=89) and non-ARDS group (n=225) according to whether there was ARDS within 7 d of admission. Risk factors for ARDS were identified using Logistic regression. The C-statistic expressed as a percentage [area under curve (AUC) of the receiver operating characteristic (ROC) curve] was used to assess the discrimination of the model.

RESULTS

The incidence of ARDS after traumatic hemorrhagic shock was 28.34%. Finally, Logistic regression model showed that the independent risk factors of ARDS after traumatic hemorrhagic shock included male, history of coronary heart disease, high acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score, road traffic accident and elevated troponin Ⅰ. The OR and 95% confidence intervals (CI) were 4.01 (95%CI: 1.75-9.20), 5.22 (95%CI: 1.29-21.08), 1.07 (95%CI: 1.02-1.57), 2.53 (95%CI: 1.21-5.28), and 1.26 (95%CI: 1.02-1.57), respectively; the P values were 0.001, 0.020, 0.009, 0.014, and 0.034, respectively. The ROC curve was used to analyze the value of each risk factor in predicting ARDS. It was found that the AUC for predicting ARDS after traumatic hemorrhagic shock was 0.59 (95%CI: 0.51-0.68) for male, 0.55 (95%CI: 0.46-0.64) for history of coronary heart disease, 0.65 (95%CI: 0.57-0.73) for APACHE Ⅱ score, 0.58 (95%CI: 0.50-0.67) for road traffic accident, and 0.73 (95%CI: 0.66-0.80) for elevated troponin Ⅰ, with an overall predictive value of 0.81 (95%CI: 0.74-0.88).

CONCLUSION

The incidence of ARDS in patients with traumatic hemorrhagic shock is high, and male, history of coronary heart disease, high APACHE Ⅱ score, road traffic accident and elevated troponin Ⅰ are independent risk factors for ARDS after traumatic hemorrhagic shock. Timely monitoring these indicators is conducive to early detection and treatment of ARDS after traumatic hemorrhagic shock.

Serum asprosin levels are increased in patients with periodontitis and ST-segment elevation myocardial infarction and correlated with periodontal parameters: A case-control study

OBJECTIVE

The study aims to investigate whether patients with ST-elevation myocardial infarction (STEMI)-related periodontitis will experience any changes in asprosin levels.

BACKGROUND

Periodontitis is a common, chronic infection of the periodontium that is epidemiologically associated with cardiovascular disease. Although asprosin, a hormone released from adipose tissue, is a protective role in cardiovascular diseases, its effectiveness in periodontitis is unknown.

METHODS

The study was conducted on a total of 120 patients, divided into four groups; the group of healthy control (n = 35), the group of periodontitis (n = 35), the group of periodontitis+STEMI (n = 25), and the group of STEMI (n = 25). In each patient, age, serum asprosin, CRP, troponin-I, and clinical periodontal parameters [plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), and clinical attachment level (CAL)] were evaluated. The results were analyzed statistically.

RESULTS

Serum asprosin, CRP, and troponin-I levels were statistically higher in the STEMI+periodontitis group compared to the other groups. In addition, as a result of the study, it was observed that there was a correlation between serum asprosin levels, clinical periodontal parameters, and CRP levels.

CONCLUSIONS

The results of this study show that STEMI and periodontitis are associated with high asprosin levels. Since the risk of periodontitis is high in STEMI patients, periodontitis should also be considered when evaluating asprosin levels in STEMI patients.

Exercise-induced cardiac troponin release in athletes with versus without coronary atherosclerosis

The magnitude of exercise-induced cardiac troponin (cTn) elevations is dependent on cardiovascular health status, and previous studies have shown that occult coronary atherosclerosis is highly prevalent among amateur athletes. We tested the hypothesis that middle-aged and older athletes with coronary atherosclerosis demonstrate greater cTn elevations following a controlled endurance exercise test compared with healthy peers. We included 59 male athletes from the Measuring Athletes' Risk of Cardiovascular events 2 (MARC-2) study and stratified them as controls [coronary artery calcium score (CACS) = 0, n = 20], high CACS [≥300 Agatston units or ≥75th Multi-Ethnic Study of Atherosclerosis (MESA) percentile, n = 20] or significant stenosis (≥50% in any coronary artery, n = 19). Participants performed a cycling test with incremental workload until volitional exhaustion. Serial high-sensitivity cTn (hs-cTn) T and I concentrations were measured (baseline, after 30-min warm-up, and 0, 30, 60, 120, and 180 min postexercise). There were 58 participants (61 [58-69] yr) who completed the exercise test (76 ± 14 min) with a peak heart rate of 97.7 [94.8-101.8]% of their estimated maximum. Exercise duration and workload did not differ across groups. High-sensitivity cardiac troponin T (Hs-cTnT) and high-sensitivity cardiac troponin I (hs-cTnI) concentrations significantly increased (1.55 [1.33-2.14]-fold and 2.76 [1.89-3.86]-fold, respectively) over time, but patterns of cTn changes and the incidence of concentrations >99th percentile did not differ across groups. Serial sampling of hs-cTnT and hs-cTnI concentrations during and following an exhaustive endurance exercise test did not reveal differences in exercise-induced cTn release between athletes with versus without coronary atherosclerosis. These findings suggest that a high CACS or a >50% stenosis in any coronary artery does not aggravate exercise-induced cTn release in middle-aged and older athletes.NEW & NOTEWORTHY Exercise-induced cardiac troponin (cTn) release is considered to be dependent on cardiovascular health status. We tested whether athletes with coronary atherosclerosis demonstrate greater exercise-induced cTn release compared with healthy peers. Athletes with coronary atherosclerosis did not differ in cTn release following exercise compared with healthy peers. Our findings suggest that a high CACS or a >50% stenosis in any coronary artery does not aggravate exercise-induced cTn release in middle-aged and older athletes.

The effects of troponin screening among patients undergoing acute high-risk abdominal surgery: A retrospective cohort study

BACKGROUND

Acute high-risk abdominal (AHA) surgery is associated with a high short-term mortality rate. This might be partly attributed to myocardial injury after non-cardiac surgery (MINS) defined by elevated postoperative troponin levels. The myocardial injury is often asymptomatic; thus, troponin screening seems to be the best diagnostic method. We aimed to assess whether implementing troponin screening with subsequent individualised interventions as standard care is associated with reduced mortality after AHA surgery. We also explored the treatment implications in the screening period.

METHODS

A retrospective cohort of 558 patients undergoing surgery from February 2018 to March 2021 was included. The patients undergoing surgery before March 2019 served as the historical control group, while the screening group consisted of patients undergoing surgery from March 1, 2019. Troponin I was to be measured 6-12 h postoperatively and in the morning of the succeeding 4 days. Patients with myocardial injury were assessed, and treatment was individualised after multiple disciplinary consultations. The primary outcome was the unadjusted 30-day mortality rates. Inverse probability treatment weighting was used to adjust for selection bias.

RESULTS

We included 558 patients: 382 in the screening group and 176 in the historical control group. In the screening group, 15 patients (3.9%) died before the first blood sampling, and in 31 patients (8.1%), troponin screening was omitted, leaving only 336 patients screened. Myocardial injury was diagnosed in 81 patients (24.1%) of the 336 patients. Of these, 59 (72.8%) had a cardiac consultation. No interventions or alterations in relation to myocardial injury were done in 67 patients (82.7%). The 30-day mortality was 13.8% (95% CI 8.7%-18.9%) in the control group and 11.1% (95% CI 8.0%-14.3%) in the screening group. The absolute risk difference was -2.7% (95% CI -8.7%-3.3%; p = .38), which was unchanged after adjustment. The difference remained unchanged after 90 days and 1 year.

CONCLUSION

The implementation of postoperative troponin screening was not associated with reduced mortality after AHA surgery. Research on the prevention and treatment of MINS is warranted before the implementation of standard troponin screening.

In suspected ACS, hs-cTnI- vs. c-cTnI-guided care was associated with improved outcomes at 5 y in certain subgroups

SOURCE CITATION

Lee KK, Doudesis D, Ferry AV, et al; High-STEACS Investigators. Implementation of a high sensitivity cardiac troponin I assay and risk of myocardial infarction or death at five years: observational analysis of a stepped wedge, cluster randomised controlled trial. BMJ. 2023;383:e075009. 38011922.

An ultrasensitive unlabeled electrochemical immunosensor for the detection of cardiac troponin I based on Pt/Au-B,S,N-rGO as the signal amplification platform

In this study, an ultrasensitive unlabeled electrochemical immunosensor for the detection of cardiac troponin I (cTnI) was developed based on Pt/Au modified B,S,N co-doped reduced graphene oxide (Pt/Au-B,S,N-rGO) as a signal amplification platform. First-principles calculations were employed to analyze the electron density of states of Pt/Au-B,S,N-rGO, revealing an increase in the electron density of the graphene oxide (GO) states. Furthermore, scanning electron microscopy (SEM), X-ray photoelectron diffraction spectroscopy (XPS), and electrochemical detection were used to successfully construct and analyze Pt/Au-B,S,N-rGO. The results showed that B,S,N-rGO exhibited good electrochemical activity, and the Au/Pt NPs demonstrated excellent catalytic properties, which provided a strong foundation for achieving high-sensitivity detection. Moreover, the constructed unlabeled electrochemical immunosensor had an ideal linear range (0.1 pg/mL∼50 ng/mL) and detection limit (0.082 pg/mL). In human serum detection, the results of this immunosensor were essentially similar to the ELISA results for the same samples, which suggested that the immunosensor had a promising clinical application prospect for the detection of cTnI.

Left Atrial Strain in Multisystem Inflammatory Syndrome in Children and Associations with Systemic Inflammation and Cardiac Injury

Multisystem inflammatory syndrome in children (MIS-C) commonly involves cardiac injury with both systolic and diastolic dysfunction. Left atrial strain (LAS) detects subclinical diastolic dysfunction in adults but is infrequently used in children. We evaluated LAS in MIS-C and the associations with systemic inflammation and cardiac injury. In this retrospective cohort study, LAS parameters [reservoir (LAS-r), conduit (LAS-cd), and contractile (LAS-ct)] obtained from admission echocardiograms of MIS-C patients were compared to healthy controls and between MIS-C patients with and without cardiac injury (BNP > 500 pg/ml or troponin-I > 0.04 ng/ml). Correlation and logistic regression analyses were performed to assess LAS associations with admission inflammatory and cardiac biomarkers. Reliability testing was performed. We identified 118 patients with MIS-C and 20 healthy controls. Median LAS parameters were reduced in MIS-C patients compared to controls (LAS-r: 31.8 vs. 43.1%, p < 0.001; LAS-cd: - 28.8 vs. - 34.5%, p = 0.006; LAS-ct: - 5.2 vs. - 9.3%, p < 0.001) and reduced in MIS-C patients with cardiac injury (n = 59) compared to no injury (n = 59) (LAS-r: 29.6 vs. 35.8%, p = 0.001; LAS-cd: - 26.5 vs. - 30.4%, p = 0.036; LAS-ct: - 4.6 vs. - 9.3%, p = 0.008). A discrete LAS-ct peak was absent in 65 (55%) MIS-C patients but present in all controls (p < 0.001). Procalcitonin correlated strongly with averaged E/e' (r = 0.55, p = 0.001). Moderate correlations were found for ESR and LAS-ct (r = - 0.41, p = 0.007) as well as BNP and LAS-r (r = - 0.39, p < 0.001) and LAS-ct (r = 0.31, p = 0.023). Troponin-I had only weak correlations. Intra-rater reliability was good for all LAS parameters, and inter-rater reliability was good to excellent for LAS-r, and fair for LAS-cd and LAS-ct. LAS analysis, particularly the absence of a LAS-ct peak, was reproducible and may be superior to conventional echocardiographic parameters for detecting diastolic dysfunction in MIS-C. No strain parameters on admission were independently associated with cardiac injury.

Peripheral blood indicators and COVID-19: an observational and bidirectional Mendelian randomization study

Blood is critical for health, supporting key functions like immunity and oxygen transport. While studies have found links between common blood clinical indicators and COVID-19, they cannot provide causal inference due to residual confounding and reverse causality. To identify indicators affecting COVID-19, we analyzed clinical data (n = 2,293, aged 18-65 years) from Guangzhou Medical University's first affiliated hospital (2022-present), identifying 34 significant indicators differentiating COVID-19 patients from healthy controls. Utilizing bidirectional Mendelian randomization analyses, integrating data from over 2.46 million participants from various large-scale studies, we established causal links for six blood indicators with COVID-19 risk, five of which is consistent with our observational findings. Specifically, elevated Troponin I and Platelet Distribution Width levels are linked with increased COVID-19 susceptibility, whereas higher Hematocrit, Hemoglobin, and Neutrophil counts confer a protective effect. Reverse MR analysis confirmed four blood biomarkers influenced by COVID-19, aligning with our observational data for three of them. Notably, COVID-19 exhibited a positive causal relationship with Troponin I (Tnl) and Serum Amyloid Protein A, while a negative association was observed with Plateletcrit. These findings may help identify high-risk individuals and provide further direction on the management of COVID-19.

Serial troponin-I and long-term outcomes in subjects with suspected acute coronary syndrome

AIMS

It is unclear how serial high-sensitivity troponin-I (hsTnI) concentrations affect long-term prognosis in individuals with suspected acute coronary syndrome (ACS).

METHODS AND RESULTS

Subjects who underwent two hsTnI measurements (Siemens TnI Flex® Reagent) separated by 1-7 h, during a first-time hospitalization for myocardial infarction, unstable angina, observation for suspected myocardial infarction, or chest pain from 2012 through 2019, were identified through Danish national registries. Individuals were stratified per their hsTnI concentration pattern (normal, rising, persistently elevated, or falling) and the magnitude of hsTnI concentration change (<20%, >20-50%, or >50% in either direction). We calculated absolute and relative mortality risks standardized to the distributions of risk factors for the entire study population. A total of 20 609 individuals were included of whom 2.3% had died at 30 days, and an additional 4.7% had died at 365 days. The standardized risk of death was highest among persons with a persistently elevated hsTnI concentration (0-30 days: 8.0%, 31-365 days: 11.1%) and lowest among those with two normal hsTnI concentrations (0-30 days: 0.5%, 31-365 days: 2.6%). In neither case did relative hsTnI concentration changes between measurements clearly affect mortality risk. Among persons with a rising hsTnI concentration pattern, 30-day mortality was higher in subjects with a >50% rise compared with those with a less pronounced rise (2.2% vs. <0.1%).

CONCLUSION

Among individuals with suspected ACS, those with a persistently elevated hsTnI concentration consistently had the highest risk of death. In subjects with two normal hsTnI concentrations, mortality was very low and not affected by the magnitude of change between measurements.

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.

An appraisal of the practice of duplicate testing for the detection of irregular analytical errors

OBJECTIVES

Our study aimed to determine the usefulness of duplicate testing in identifying irregular analytical errors and subsequent prevention of patient mismanagement.

METHODS

In our laboratory, all requests for Na+, Ca2+, alkaline phosphatase (ALP), and high-sensitivity cardiac-troponin-I (hs-cTnI) are run in duplicate. Data from four separate weeks for Na+ (n=21,649), Ca2+ (n=14,803) and ALP (n=19,698); and a full year for hs-cTnI (n=17,036) were gathered. For each test, pre-defined limits for differences between duplicates were used to identify erroneous results (Fliers). We further characterised a subset of such fliers as "critical errors", where duplicates fell on opposing sides of a reference/decision making threshold. The costs/benefits of running these tests in duplicate were then considered in light of increased number of tests analysed by this approach.

RESULTS

For Na+, 0.03 % of duplicates met our flier defining criteria, and 0.01 % of specimens were considered critical errors. For Ca2+ requests, 4.58 % of results met our flier defining criteria and 0.84 % were critical errors. For ALP, 0.22 % of results were fliers, and 0.01 % were critical errors. For hs-cTnI, 1.58 % of results were classified as fliers, whilst 0.14 % were classified as a critical error. Depending on the test in question, running all analyses in duplicate increased annual costs by as little as €1,100 (for sodium), and as much as €48,000 (for hs-cTnI).

CONCLUSIONS

Duplicate testing is effective at identifying and mitigating irregular laboratory errors, and is best suited for assays predisposed to such error, where costs are minimal, and clinical significance of an incorrect result can justify the practice.

Troponin T is elevated in a relevant proportion of patients with 5q-associated spinal muscular atrophy

Troponin T concentration (TNT) is commonly considered a marker of myocardial damage. However, elevated concentrations have been demonstrated in numerous neuromuscular disorders, pointing to the skeletal muscle as a possible extracardiac origin. The aim of this study was to determine disease-related changes of TNT in 5q-associated spinal muscular atrophy (SMA) and to screen for its biomarker potential in SMA. We therefore included 48 pediatric and 45 adult SMA patients in this retrospective cross-sequential observational study. Fluid muscle integrity and cardiac markers were analyzed in the serum of treatment-naïve patients and subsequently under disease-modifying therapies. We found a TNT elevation in 61% of SMA patients but no elevation of the cardiospecific isoform Troponin I (TNI). TNT elevation was more pronounced in children and particularly infants with aggressive phenotypes. In adults, TNT correlated to muscle destruction and decreased under therapy only in the subgroup with elevated TNT at baseline. In conclusion, TNT was elevated in a relevant proportion of patients with SMA with emphasis in infants and more aggressive phenotypes. Normal TNI levels support a likely extracardiac origin. Although its stand-alone biomarker potential seems to be limited, exploring TNT in SMA underlines the investigation of skeletal muscle integrity markers.

Diagnostic accuracy of baseline troponin and troponin change for the diagnosis of myocardial infarction complicated with heart failure

BACKGROUND

The diagnosis of myocardial infarction (MI) in the presence of heart failure (HF) presents a clinical problem. While diagnostic algorithms using high-sensitivity cardiac troponin have been established for suspected MI, their accuracy in patients with HF remains uncertain. This study aims to assess the diagnostic accuracy of high-sensitivity troponin I (TnI) levels in identifying acute MI among patients with HF, focusing on baseline, absolute and relative TnI changes.

METHODS

Data from 562 individuals admitted to the emergency department with suspected MI were retrospectively analysed. Two-point TnI and baseline brain natriuretic peptide (BNP) test results were available. HF status was determined based on clinical, laboratory and instrumental criteria.

RESULTS

Among the 562 patients, 299 (53.2%) were confirmed having MI. Baseline TnI demonstrated predictive capability for MI in the overall population (area under the curve (AUC) 0.63), while TnI relative change exhibited superior performance (AUC 0.83). Baseline TnI accuracy varied significantly by group, notably decreasing in the third group (severe HF) (AUC 0.54) compared with the first and second groups (AUC 0.67 and AUC 0.71, respectively). TnI relative change demonstrated consistent accuracy across all groups, with AUCs of 0.79, 0.79 and 0.89 for the first, second and third groups, respectively, even after adjustment for age, sex and glomerular filtration rate.

DISCUSSION

Troponin relative change is a reliable predictor of MI, even in patients with acute HF. Baseline TnI accuracy is influenced by HF severity. It is essential to consider HF status and BNP levels when employing high-sensitivity cardiac troponin testing to rule out suspected MIs.

The effect of Del Nido versus custodiol cardioplegia on clinical outcomes and troponin-I changes among pediatrics with tetralogy of fallot undergoing cardiopulmonary bypass

BACKGROUND

Myocardial protection during operations with cardiopulmonary bypass (CPB) and aortic cross clamping is vital. For this purpose, Del Nido (DN) and Custodiol cardioplegia (CC) solutions are used for single-dose cardioplegia in cardiac surgical procedures with CPB. Present study aimed to compare the effects of DN and CC on peri-operative clinical outcomes in pediatrics with Tetralogy of Fallot (TF) undergoing cardiopulmonary bypass.

METHODS

Present randomized clinical trial was performed in two trial groups with parallel design. One group received DN and another group received CC. We assessed circulatory Troponin-I (cTnI) and coronary sinus lactate level as primary outcomes. Secondary outcomes were ventilation time, electrolytes levels, pump time, cross-clamp time and other clinical parameters.

RESULTS

Duration of CPB and cross-clamp were the same in both groups. There were no significant differences in hemodynamic parameters, left ventricular ejection fraction after the surgery and discharge time between the two trial groups. Ventilation time (8.5 vs. 18; p = 0.001), ICU stay, Troponin-I in ICU admission and Coronary sinus lactate level (p = 0.001) were significantly higher among patients of Custodiol group compared to other trial group. Electrolytes Na, Cl and K levels, during CPB, were significantly less in Custodiol group.

CONCLUSION

When used for inducing cardiac arrest during CPB, DN solution offers better maintenance of the electrolyte balance during CPB, and is associated with less circulatory cTnI and coronary sinus lactate level compared with the CC.

Practical approaches to the detection of macrotroponin

INTRODUCTION

Macrotroponin is increasingly recognised as a cause of confusion in interpreting high-sensitivity cardiac troponin (hs-cTnI) results. In this study, we sought to evaluate two practical approaches to detecting macrotroponin. These two approaches are PEG precipitation and SVM (support vector machine) analysis to classify discrepancies between hs-cTn assays.

METHOD

Residual serum and heparin plasma specimens (n = 483) with initially elevated hs-cTnI from hospital and community laboratories were retested on multiple hs-cTn platforms before and after PEG precipitation and Protein A immunoglobulin depletion. SVM analysis was conducted to identify a linear equation that best discriminated specimens with macrotroponin using a combination of results from two different hs-cTn assays.

FINDINGS

The diagnostic performance of PEG precipitation was carried out using Protein A immunoglobulin depletion as the reference comparator. When a cutoff residual activity after PEG precipitation of ≤ 20% was used, this threshold carried a high specificity of 92% (confidence interval 83-98%; n = 189) using the Siemens hs-cTnI Vista assay and 95% specificity (86%-98%; n = 242) using the Abbott hs-cTnI Architect assay. SVM analysis generated a linear equation identifying macrotroponin specimens from results obtained on two hs-cTn assays. This approach can be highly specific, comparable to PEG precipitation when certain assay combinations and concentrations are used.

CONCLUSION

We describe and identify practical alternatives to detecting macrotroponin. These approaches can be optimised for high specificity, reducing the need for more complex laboratory methods.

The role of circulating biomarkers in predicting the 30-day mortality of immune checkpoint inhibitors-related myocarditis: a retrospective cohort study

Immune checkpoint inhibitors-related myocarditis (ICIs-M) is a rare and highly lethal immune-related adverse events (irAEs) in common irAEs. This study aims to find circulating biomarkers that can reflect disease state and prognosis accurately. 48 patients with ICIs-M were enrolled according to the diagnostic criteria for ICIs-related myocarditis. For all enrolled patients, valuable information was extracted retrospectively from the medical system, mainly including demographic information, tumor information and laboratory examination. The follow-up period was defined as 30 days after the first diagnosis of ICIs-M. In this study, the 30-day mortality rate of ICIs-M was 24.4%. After adjusting for potential confounding factors using multivariate analysis tools, we demonstrated the excellent performance of biomarkers in predicting 30-day mortality in patients with ICIs-M, including PLT (hazard ratio (HR), 1.07; 95% confidence interval (95%CI), 1.01-1.14; p = 0.028), ALT (HR, 1.23; 95%CI, 1.06-1.41; p = 0.005), AST(HR, 1.06; 95%CI, 1.01-1.10; p = 0.015), LDH (HR, 1.15; 95%CI, 1.04-1.26; p = 0.004), troponin I(HR, 1.44; 95%CI, 1.09-1.89; p = 0.009), PLR (blood plate/lymphocyte) (HR, 1.04; 95% CI, 1.01-1.07; p = 0.024), LAR (lactate dehydrogenase/albumin) (HR, 1.05; 95%CI, 1.01-1.09; p = 0.012), and AAR (aspartate transaminase/albumin) (HR, 1.18; 95%CI, 1.00-1.39; p = 0.048). The analysis of the receiver operating characteristic showed that biomarkers with area under curve (AUC) greater than or equal to 0.80 were LDH (cutoff value, 724.5; AUC, 0.86; 95%CI, 0.75-0.97), LAR (cutoff value, 18.11; AUC, 0.87; 95%CI, 0.76-0.97), troponin I (cutoff value, 0.87; AUC, 0.80; 95%CI, 0.62-0.99), and AAR(cutoff value, 1.52; AUC, 0.80; 95%CI, 0.61-0.98). LDH, LAR, troponin I, and AAR are a group of promising biomarkers that demonstrate excellent predictive ability in predicting the 30-day mortality rate of immune-related myocarditis.

Glutamate 139 of tropomyosin is critical for cardiac thin filament blocked-state stabilization

The cardiac thin filament proteins troponin and tropomyosin control actomyosin formation and thus cardiac contractility. Calcium binding to troponin changes tropomyosin position along the thin filament, allowing myosin head binding to actin required for heart muscle contraction. The thin filament regulatory proteins are hot spots for genetic mutations causing heart muscle dysfunction. While much of the thin filament structure has been characterized, critical regions of troponin and tropomyosin involved in triggering conformational changes remain unresolved. A poorly resolved region, helix-4 (H4) of troponin I, is thought to stabilize tropomyosin in a position on actin that blocks actomyosin interactions at low calcium concentrations during muscle relaxation. We have proposed that contact between glutamate 139 on tropomyosin and positively charged residues on H4 leads to blocking-state stabilization. In this study, we attempted to disrupt these interactions by replacing E139 with lysine (E139K) to define the importance of this residue in thin filament regulation. Comparison of mutant and wild-type tropomyosin was carried out using in-vitro motility assays, actin co-sedimentation, and molecular dynamics simulations to determine perturbations in troponin-tropomyosin function caused by the tropomyosin mutation. Motility assays revealed that mutant thin filaments moved at higher velocity at low calcium with increased calcium sensitivity demonstrating that tropomyosin residue 139 is vital for proper tropomyosin-mediated inhibition during relaxation. Similarly, molecular dynamic simulations revealed a mutation-induced decrease in interaction energy between tropomyosin-E139K and troponin I (R170 and K174). These results suggest that salt-bridge stabilization of tropomyosin position by troponin IH4 is essential to prevent actomyosin interactions during cardiac muscle relaxation.

Improved sensitivity and automation of a multi-step upconversion lateral flow immunoassay using a 3D-printed actuation mechanism

The development of sensitive point-of-care (POC) assay platforms is of interest for reducing the cost and time of diagnostics. Lateral flow assays (LFAs) are the gold standard for POC systems, but their sensitivity as such is inadequate, for example, in the case of cardiac diagnostics. The performance can be improved by incorporating different steps, such as pre-incubation to prolong the interaction time between sample and reporter for immunocomplex formation, and washing steps for background reduction. However, for POC assays, manual steps by the assay conductor are not desired. In this research, upconverting nanoparticles (UCNPs) were coated with poly(acrylic acid) (PAA) and conjugated to anti-cTnI antibodies, yielding non-clustering particles with low non-specific binding. The performance of cTnI-LFA in the PAA-anti-cTnI-UCNPs was compared to the same UCNPs with a commercial carboxyl surface. A kitchen-timer mechanism was embedded in a 3D-printed housing to produce a low-cost actuator facilitating a timed pre-incubation step for reporter and sample, and a washing step, to enable a multi-step cTnI-LFA with minimized manual labour. PAA-UCNPs showed improved mobility on nitrocellulose compared to those with a commercial surface. The mechanical actuator system was shown to improve sensitivity compared to a labour-intensive multi-step dipstick method, despite pre-incubation occurring during shaking and heating in the dipstick method. The limit of detection decreased from 7.6 to 1.5 ng/L cTnI in human plasma. The presented actuator can be easily modified for sensitivity improvement in the LFA for different analytes via pre-incubation and washing steps.

Troponin efficacy in the diagnosis of acute coronary syndrome in patients with chronic renal failure

There is no consensus on whether cardiac troponins with high reliability values should be different diagnostic criteria for acute myocardial infarction in patients with and without renal dysfunction. Although it is often emphasized that the etiology of elevated troponin levels in chronic kidney disease (CKD) remains unclear, elevated cardiac troponin (cTnT) levels have been associated with increased subclinical cardiac damage in these patient groups. In this study, we investigated the value of cTnT value in diagnosing acute coronary syndrome in CKD patients with high clinical suspicion of acute coronary syndrome and without acute ST segment elevation on electrocardiogram. The aim was to prevent cardiac ischemia from being overlooked in CKD patients. Coronary angiography revealed vessel occlusion in 192 patients, and the mortality rate after treatment decisions was 6.7%. The first measured troponin results showed a significant difference in patients who did not survive, indicating the prognostic value of troponin levels. Troponin values were compared with cardiovascular pathologies obtained by angiography, and elevated troponin levels strongly correlated with pathologic angiography results. The conclusion highlighted that despite prognostic uncertainties, biomarkers used for acute myocardial infarction diagnosis in patients with renal insufficiency are reliable in those with renal dysfunction. Elevated cTnT levels in CKD patients are considered a clear marker of cardiac ischemia, emphasizing the need for careful consideration of troponin values in this population.

Serial high sensitivity troponin sampling in patients with SARS-CoV-2 infection

INTRODUCTION

Multiple studies have investigated the role of cardiac troponin (cTn) in the risk stratification of patients with COVID-19. Most of these investigations are based on cTn values at presentation and do not consider the prognostic significance of cTn changes over time. This study aimed to investigate the prognostic role of serial cTn measurements in patients hospitalized with COVID-19 with samples that were not obtained for clinical indications.

METHODS

Patients hospitalized between April 2020 and March 2021 with PCR-confirmed SARS-CoV-2 infection were evaluated. Blood samples collected for any reason were stored for subsequent analysis. If clinical high sensitivity hs-cTnT (Roche) was not measured, samples were tested separately in batches. Hs-cTnI (Abbott) was also evaluated.

RESULTS

There were 228 unique patients. There were 21 (9.2 %) deaths. No patient with a low hs-cTnT (<6 ng/L) died and 1 patient with low hs-cTnI (<5 ng/L) died. Myocardial injury was associated with higher odds of death, when defined by hs-cTnT (OR: 7.88, 95 % CI: 2.04-30.40, p = 0.003) or hs-cTnI (OR: 7.46, 95 % CI: 2.68-20.77, p < 0.001). This association remained after propensity weighting. An increasing pattern was associated with higher odds of death compared to a stable pattern for hs-cTnT (OR: 5.45, 95 % CI: 1.81-16.40, p = 0.003) and hs-cTnI (OR: 4.49, 95 % CI: 1.02-19.81, p = 0.048). Among patients with myocardial injury defined by hs-cTnT, an increasing pattern was associated with higher odds of death compared to a decreasing pattern (OR: 4.80, 95 % CI: 1.16-19.97, p = 0.031).

CONCLUSIONS

Patients hospitalized with COVID-19 with myocardial injury have higher odds of death. Serial hs-cTn testing provides additional risk stratification in these patients.

Distribution and prognostic value of high-sensitivity cardiac troponin T and I across glycemic status: a population-based study

BACKGROUND

Whether distributions and prognostic values of high-sensitivity cardiac troponin (hs-cTn) T and I are different across normoglycemic, prediabetic, and diabetic populations is unknown.

METHODS

10127 adult participants from the National Health and Nutrition Examination Survey 1999-2004 with determined glycemic status and measurement of at least one of hs-cTn assays were included, from whom healthy participants and presumably healthy diabetic and prediabetic participants were selected to investigate pure impacts of glycemic status on distributions of hs-cTn. The nonparametric method and bootstrapping were used to derive the 99th upper reference limits of hs-cTn and 95% CI. Participants with available follow-up and hs-cTn concentrations of all 4 assays were included in prognostic analyses. Associations of hs-cTn with all-cause and cardiac-specific mortality were modeled by Cox proportional hazard regression under the complex survey design. The incremental value of hs-cTn to an established risk score in predicting cardiac-specific mortality was assessed by the 10-year area under time-dependent receiver operating characteristic curve (AUC) using the Fine-Grey competing risk model.

RESULTS

Among 9714 participants included in prognostic analyses, 5946 (61.2%) were normoglycemic, 2172 (22.4%) prediabetic, and 1596 (16.4%) diabetic. Hyperglycemic populations were older than the normoglycemic population but sex and race/ethnicity were similar. During the median follow-up of 16.8 years, hs-cTnT and hs-cTnI were independently associated with all-cause and cardiac-specific mortality across glycemic status. In the diabetic population, adjusted hazard ratios per 1-standard deviation increase of log-transformed hs-cTnT and hs-cTnI (Abbott) concentrations were 1.77 (95% CI 1.48-2.12; P < .001) and 1.83 (95% CI 1.33-2.53; P < .001), respectively, regarding cardiac-specific mortality. In the diabetic but not the normoglycemic population, adding either hs-cTnT (difference in AUC: 0.062; 95% CI 0.038-0.086; P < 0.001) or hs-cTnI (Abbott) (difference in AUC: 0.071; 95% CI 0.046-0.097; P < 0.001) would significantly increase the discriminative ability of the risk score; AUC of the score combined with hs-cTnT would be further improved by incorporating hs-cTnI (0.018; 95%CI 0.006-0.029; P = 0.002). The 99th percentile of hs-cTnT of the presumably healthy diabetic population was higher than the healthy population and had no overlap in 95% CIs, however, for hs-cTnI 99th percentiles of the two populations were very close and 95% CIs extensively overlapped.

CONCLUSIONS

Hs-cTnT and hs-cTnI demonstrated consistent prognostic associations across glycemic status but incremental predictive values in hyperglycemic populations only. The susceptibility of hs-cTnT 99th percentiles to diabetes plus the additive value of hs-cTnI to hs-cTnT in diabetic cardiovascular risk stratification suggested hs-cTnI and hs-cTnT may be differentially associated with glycemic status, but further research is needed to illustrate the interaction between hyperglycemia and hs-cTn.

Plug-and-play smart transistor bio-chips implementing point-of-care diagnosis of AMI with modified CRISPR/Cas12a system

The point-of-care diagnosis of acute myocardial infarction (AMI), an extremely lethal disease with only a few hours of golden rescue time, is significant and urgently required. Here, we describe a plug-and-play carbon nanotube field effect transistor (CNT-FET) bio-chip supported with a smart portable readout for ultrasensitive and on-site testing of cardiac troponin I (cTnI), which is one of the most specific and valuable biomarkers of AMI. A modified clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a system, featuring the G-triplex structured reporter, was first combined with the CNT-FET to realize non-nucleic acid detection. Such a unique CNT-FET biosensor achieved the high sensitivity (LOD: 0.33 fg/mL), which is expected to give timely warning in the early stage of myocardial injury. In addition, a bilayer gate dielectric consisting of Y2O3/HfO2, employed into the passivation process, enabled the high environmental stability and repeatability of CNT-FET. More importantly, the homemade compact chip readout forged a field-deployable cTnI analytical tool, realizing "plasma-to-answer" performance for AMI patients in point-of-care testing scenarios. The developed technology holds promise to help doctors make clinical decisions faster, especially in remote areas.

Accelerating the Phosphatase-like Activity of Uio-66-NH2 by Catalytically Inactive Metal Ions and Its Application for Improved Fluorescence Detection of Cardiac Troponin I

Compared with natural enzymes, nanozymes usually exhibit much lower catalytic activities, which limit the sensitivities of nanozyme-based immunoassays. Herein, several metal ions without enzyme-like activities were engineered onto Uio-66-NH2 nanozyme through postsynthetic modification. The obtained Mn+@Uio-66-NH2 (Mn+ = Zn2+, Cd2+, Co2+, Ca2+and Ni2+) exhibited improved phosphatase-like catalytic activities. In particular, a 12-fold increase in the catalytic efficiency (kcat/Km) of Uio-66-NH2 was observed after the modification with Zn2+. Mechanism investigations indicate that both the amino groups and oxygen-containing functional groups in Uio-66-NH2 are the binding sites of Zn2+, and the modified Zn2+ ions on Uio-66-NH2 serve as the additional catalytic sites for improving the catalytic performance. Furthermore, the highly active Zn2+@Uio-66-NH2 was used as a nanozyme label to develop a fluorescence immunoassay method for the detection of cardiac troponin I (cTnI). Compared with pristine Uio-66-NH2, Zn2+@Uio-66-NH2 can widen the linear range by 1 order of magnitude (from 10 pg/mL-1 μg/mL to 1 pg/mL-1 μg/mL) and also lower the detection limit by 5 times (from 4.7 pg/mL to 0.9 pg/mL).

Development and validation of cardiac diffusion weighted magnetic resonance imaging for the diagnosis of myocardial injury in small animal models

Cardiac diffusion weighted-magnetic resonance imaging (DWI) has slowly developed due to its technical difficulties. However, this limitation could be overcome by advanced techniques, including a stimulated echo technique and a gradient moment nulling technique. This study aimed to develop and validate a high-order DWI sequence, using echo-planar imaging (EPI) and second-order motion-compensated (M012) diffusion gradient applied to cardiac imaging in small-sized animals with fast heart and respiratory rates, and to investigate the feasibility of cardiac DWI, diagnosing acute myocardial injury in isoproterenol-induced myocardial injury rat models. The M012 diffusion gradient sequence was designed for diffusion tensor imaging of the rat myocardium and validated in the polyvinylpyrrolidone phantom. Following sequence optimization, 23 rats with isoproterenol-induced acute myocardial injury and five healthy control rats underwent cardiac MRI, including cine imaging, T1 mapping, and DWI. Diffusion gradient was applied using a 9.4-T MRI scanner (Bruker, BioSpec 94/20, gradient amplitude = 440 mT/m, maximum slew rate = 3440 T/m/s) with double gating (electrocardiogram and respiratory gating). Troponin I was used as a serum biomarker for myocardial injury. Histopathologic examination of the heart was subsequently performed. The developed DWI sequence using EPI and M012 provided the interpretable images of rat hearts. The apparent diffusion coefficient (ADC) values were significantly higher in rats with acute myocardial injury than in the control group (1.847 ± 0.326 * 10-3 mm2/s vs. 1.578 ± 0.144 * 10-3 mm2/s, P < 0.001). Troponin I levels were increased in the blood samples of rats with acute myocardial injury (P < 0.001). Histopathologic examinations detected myocardial damage and subendocardial fibrosis in rats with acute myocardial injury. The newly developed DWI technique has the ability to detect myocardial injury in small animal models, representing high ADC values on the myocardium with isoproterenol-induced injury.

Diagnostic and prognostic value of the sex-specific 99th percentile of four high-sensitivity cardiac troponin assays in patients with suspected myocardial infarction

AIMS

High-sensitivity cardiac troponin (hs-cTn) assays are used for detection of myocardial infarction (MI). Ninety-ninth percentiles show wide inter-assay variation. The use of sex-specific cut-offs is recommended as definitory cut-off for MI. We compared diagnostic performance and prognostic value of sex-specific 99th percentiles of four hs-cTn assays in patients with suspected MI.

METHODS AND RESULTS

Concentrations of four hs-cTn assays were measured at presentation and after 3 h in patients with suspected MI. Final diagnoses were adjudicated according to the 4th Universal Definition of MI. Unisex and sex-specific 99th percentiles were evaluated as diagnostic cut-offs following the ESC 0/3 h algorithm. These cut-offs were used in Cox-regression analyses to investigate the association with a composite endpoint of MI, revascularization, cardiac rehospitalization, and death. Non-ST-elevation MI was diagnosed in 368 of 2718 patients. Applying the unisex 99th percentile, Elecsys hs-cTnT provided highest negative predictive value (NPV) of 99.7 and a positive predictive value (PPV) of 75.9. The analysed hs-cTnI assays showed slightly lower NPVs and comparable PPVs [Architect (NPV 98.0, PPV of 71.4); Atellica (NPV 97.7, PPV of 76.1); Pathfast (NPV 97.7, PPV of 66.6)]. Application of sex-specific 99th percentiles did not significantly affect diagnostic performance. Concentrations above 99th percentile were independent predictors for impaired long-term outcome (hazard ratios 1.2-1.5, P < 0.001).

CONCLUSION

We describe a good diagnostic accuracy of four hs-cTn assays using the assay-specific 99th percentile for detection of MI. Application of sex-specific 99th percentiles did neither affect diagnostic performance nor prognostic value significantly. Finally, values above the 99th percentile were associated with poor long-term outcome.

Antibody-functionalized gold nanoclusters/gold nanoparticle platform for the fluorescence turn-on detection of cardiac troponin I

A selective fluorescence turn-on immunosensor for the specific detection of cardiac troponin I (cTnI), the potent biomarker for myocardial infarction diagnosis, was developed with a nano couple comprised of protein-stabilized gold nanocluster and gold nanoparticle. The red fluorescence of cTnI-specific antibody tagged bovine serum albumin stabilized gold nanoclusters was quenched with gold nanoparticles (AuNP) via the intensive interaction between amine and hydroxyl functionalities of BSA and AuNP. Through this, the adsorption of gold nanoclusters at the surface of AuNP, resulting in a core-satellite assembly, was assumed to quench the fluorescence emission. While in the presence of cTnI antigen, this gets disturbed due to the formation of immunocomplex between cTnI antigen and antibody, which restricts the close interaction between gold clusters and nanoparticles, thereby restoring quenched fluorescence. The enhancement in fluorescence signal is directly related to the concentration of cTnI, and this facilitates the selective detection of cTnI in the linear concentration range 0.7 to 10 ng/mL without any interference from other potentially interfering co-existing biomolecules. An appreciable limit of detection of 0.51 ng/mL and a limit of quantification of 0.917 ng/mL for cTnI is comparable to that of the previous report.

High-Sensitivity Cardiac Troponins I and T and Cardiovascular Outcomes: Findings from the Systolic Blood Pressure Intervention Trial (SPRINT)

BACKGROUND

Cardiac troponins are associated with adverse cardiovascular disease (CVD) outcomes. The value of high-sensitivity cardiac troponin I (hs-cTnI) independently and in concert with troponin T (hs-cTnT) in the management of hypertension has not been well studied.

METHODS

We assessed the utility of hs-cTnI independently and with hs-cTnT in identifying the highest risk individuals in the Systolic Blood Pressure Intervention Trial (SPRINT). Among 8796 eligible SPRINT participants, hs-cTnI was measured at baseline and 1 year. The association of baseline level and 1-year change in hs-cTnI with CVD events and all-cause death was evaluated using adjusted Cox regression models. We further assessed the complementary value of hs-cTnI and hs-cTnT by identifying concordant and discordant categories and assessing their association with outcomes.

RESULTS

hs-cTnI was positively associated with composite CVD risk [myocardial infarction, other acute coronary syndrome, stroke, or cardiovascular death: hazard ratio 1.23, 95% confidence interval 1.08-1.39 per 1-unit increase in log(troponin I)] independent of traditional risk factors, N-terminal pro-B-type natriuretic peptide, and hs-cTnT. Intensive blood pressure lowering was associated with greater absolute risk reduction (4.5% vs 1.7%) and lower number needed to treat (23 vs 59) for CVD events among those with higher baseline hs-cTnI (≥6 ng/L in men, ≥4 ng/L in women). hs-cTnI increase at 1 year was also associated with increased CVD risk. hs-cTnI and hs-cTnT were complementary, and elevations in both identified individuals with the highest risk for CVD and death.

CONCLUSIONS

Baseline levels and change in hs-cTnI over 1 year identified higher-risk individuals who may derive greater cardiovascular benefit with intensive blood pressure treatment. hs-TnI and hs-TnT have complementary value in CVD risk assessment. ClinicalTrials.gov Registration Number: NCT01206062.

Pseudo-targeted metabolic profile differences between emergency patients with type 1 and type 2 myocardial infarction diagnosed by optical coherence tomography

BACKGROUND

It is difficult to distinguish type 2 myocardial infarction (T2MI) from type 1 myocardial infarction (T1MI), although their management varies.

OBJECTIVES

Using optical coherence tomography (OCT) and pseudo-targeted metabolomics to identify biomarkers, investigate metabolic differences, and establish a T2MI subclassification.

METHODS

Among 1519 patients with MI, 97 T2MI patients are identified who are 1:1 matched with 97 T1MI patients after considering age, gender, ST-segment elevation, time from onset to coronary angiography, and hs-cTnI on admission by propensity score matching. Plasma pseudo-targeted metabolomics at baseline was determined.

RESULTS

The clinical characteristics of the two groups were comparable, while the T1MI showed more severe coronary lesions than T2MI according to OCT imaging. 90 differential metabolites were identified between the two groups, among 1027 endogenous metabolites in 20 classes. N-Acetyl-L-Leucine, free fatty acid (15:1), Thymidine-5'-triphosphate, Mevalonic acid 5-pyrophosphate, and five oligopeptides were candidate biomarkers (AUC ≥ 0.85) distinguishing T2MI from T1MI. 12 KEGG pathways showed significant differences, mainly involving amino acid, nucleotide, and their derivatives metabolism, and signaling pathways such as mTOR, cGMP-PKG, and cAMP. Other differences were observed in TCA cycle (P = 0.08) and ROS (P = 0.05). Proteolysis and coronary heart disease risk lipid level were lower in T2MI. T2MI had a decrease of differential abundance score in almost all the KEGG enrichment pathways. Furthermore, T2MI can be subdivided into three subtypes by hierarchical cluster analysis of AUCs with causes/triggers of T2MI.

CONCLUSIONS

There are significant metabolic profile differences between T1MI and T2MI. Several candidate metabolic biomarkers can effectively distinguish the two groups.

CLINICAL TRIAL REGISTRATION

ClinicalTrials. gov NCT03297164.

External validation of the 0/1h-algorithm and derivation of a 0/2h-algorithm using a new point-of-care Hs-cTnI assay

BACKGROUND

The high-sensitivity cardiac troponin (hs-cTn) I point-of-care (POC) hs-cTnI-PATHFAST assay has recently become clinically available.

METHODS

We aimed to externally validate the hs-cTnI-PATHFAST 0/1h-algorithm recently developed for the early diagnosis of non-ST-segment-elevation myocardial infarction (NSTEMI) and derive and validate a 0/2-algorithm in patients presenting to the emergency department with acute chest discomfort included in a multicenter diagnostic study. Two independent cardiologists centrally adjudicated the final diagnoses using all the clinical and study-specific information available including serial measurements of hs-cTnI-Architect.

RESULTS

Among 1,532 patients (median age 60 years, 33% [n = 501] women), NSTEMI was the final diagnosis in 13%. External validation of the hs-cTnI-PATHFAST 0/1h-algorithm showed very high negative predictive value (NPV; 100% [95%CI, 99.5%-100%]) and sensitivity 100% (95%CI, 98.2%-100%) for rule-out of NSTEMI. Positive predictive value (PPV) and specificity for rule-in of NSTEMI were high (74.9% [95%CI, 68.3%-80.5%] and 96.4% [95%CI, 95.2%-97.3%], respectively). Among 1,207 patients (median age 61 years, 32% [n = 391] women) available for the derivation (n = 848) and validation (n = 359) of the hs-cTnI-PATHFAST 0/2h-algorithm, a 0h-concentration <3 ng/L or a 0h-concentration <4 ng/L with a 2h-delta <4ng/L ruled-out NSTEMI in 52% of patients with a NPV of 100% (95%CI, 98-100) and sensitivity of 100% (95%CI, 92.9%-100%) in the validation cohort. A 0h-concentration ≥90ng/L or a 2h-delta ≥ 55ng/L ruled-in 38 patients (11%): PPV 81.6% (95%CI, 66.6-90.8), specificity 97.7% (95%CI, 95.4-98.9%).

CONCLUSIONS

The POC hs-cTnI-PATHFAST assay allows rapid and effective rule-out and rule-in of NSTEMI using both a 0/1h- and a 0/2h-algorithm with high NPV/sensitivity for rule-out and high PPV/specificity for rule-in.

CLINICAL TRIAL REGISTRATION

NCT00470587.

Ratio of P-Wave Duration to P-Wave Amplitude and Left Atrial Remodeling: Insights from Electrophysiological Findings and Myocardial Injury After Cryoballoon Ablation

The impact of the P-wave morphology on clinical outcomes postcatheter ablation (post-CA) and recurrent arrhythmia characteristics or electrophysiologic findings in patients with paroxysmal atrial fibrillation (PAF) remains unclear. Patients with PAF who underwent cryoballoon ablation were enrolled. In 12-lead electrocardiography recorded within 1 month before CA, the P-wave duration (Pd) and P-wave vector magnitude (Pvm) (square root of the sum of the squared P-wave amplitude in leads II, V6, and one-half of the P-wave amplitude in V2) were measured and divided into 2 groups: patients with high and low Pd/Pvm based on a statistically calculated cut-off value. We evaluated the incidence of late recurrence of atrial fibrillation (LRAF), myocardial injury (high-sensitive troponin I), and the electrophysiologic findings in repeat ablation sessions. This study included 269 patients with PAF. The median follow-up duration was 697 days. The cut-off value of the Pd/Pvm for predicting LRAF was 740.7 ms/mV (area under the curve = 0.81, sensitivity = 58.2%, and specificity = 89.6%). Multivariable Cox proportional hazards analysis showed that high Pd/Pvm (>740.7 ms/mV) was significantly associated with LRAF (p <0.001). The high-sensitive troponin I level was significantly lower, and the ratio of DR-FLASH score >3 was significantly higher in those with high than low Pd/Pvm (p = 0.044 and p = 0.002, respectively). In the repeat ablation sessions, the Pd/Pvm in patients with atrial tachycardia-induced or spontaneously occurring during the repeat CA sessions was significantly higher than in those without (p = 0.009). There was a significant difference between the Pd/Pvm and low-voltage area (p <0.001). In conclusion, the Pd/Pvm is significantly associated with LRAF after cryoballoon ablation in patients with PAF and predicts left atrial low-voltage areas and atrial tachycardia inducibility.

Sex Differences in the Clinical Presentation and Natural History of Dilated Cardiomyopathy

BACKGROUND

Biological sex has a diverse impact on the cardiovascular system. Its influence on dilated cardiomyopathy (DCM) remains unresolved.

OBJECTIVES

This study aims to investigate sex-specific differences in DCM presentation, natural history, and prognostic factors.

METHODS

The authors conducted a prospective observational cohort study of DCM patients assessing baseline characteristics, cardiac magnetic resonance imaging, biomarkers, and genotype. The composite outcome was cardiovascular mortality or major heart failure (HF) events.

RESULTS

Overall, 206 females and 398 males with DCM were followed for a median of 3.9 years. At baseline, female patients had higher left ventricular ejection fraction, smaller left ventricular volumes, less prevalent mid-wall myocardial fibrosis (23% vs 42%), and lower high-sensitivity cardiac troponin I than males (all P < 0.05) with no difference in time from diagnosis, age at enrollment, N-terminal pro-B-type natriuretic peptide levels, pathogenic DCM genetic variants, myocardial fibrosis extent, or medications used for HF. Despite a more favorable profile, the risk of the primary outcome at 2 years was higher in females than males (8.6% vs 4.4%, adjusted HR: 3.14; 95% CI: 1.55-6.35; P = 0.001). Between 2 and 5 years, the effect of sex as a prognostic modifier attenuated. Age, mid-wall myocardial fibrosis, left ventricular ejection fraction, left atrial volume, N-terminal pro-B-type natriuretic peptide, high-sensitivity cardiac troponin I, left bundle branch block, and NYHA functional class were not sex-specific prognostic factors.

CONCLUSIONS

The authors identified a novel paradox in prognosis for females with DCM. Female DCM patients have a paradoxical early increase in major HF events despite less prevalent myocardial fibrosis and a milder phenotype at presentation. Future studies should interrogate the mechanistic basis for these sex differences.

Association between troponin I levels and mortality among patients undergoing acute high-risk abdominal surgery-A cohort study

BACKGROUND

Myocardial injury after noncardiac surgery (MINS) is associated with 30-day mortality in heterogeneous surgical populations but is barely described after acute high-risk abdominal surgery. The impact of dynamic changes has not previously been investigated. The objectives were to determine the incidence of MINS in this population, the association between mortality and MINS, and whether plasma troponin I (TnI) dynamics have any impact on mortality.

METHODS

A prospective cohort study of 341 patients undergoing acute high-risk gastrointestinal surgery was conducted. Plasma TnI was measured at the first four postoperative days. MINS was defined as any increased TnI level >59 ng/L. TnI dynamic required either two succeeding measurements of TnI >59 ng/L with a >20% increase/fall or one measurement of TnI >59 ng/L with a succeeding measurement of TnI <59 ng/L with a >50% decrease. Adjusted mortality rates were calculated using inverse probability of treatment weighting and competing risk analyses.

RESULTS

The incidence of MINS was 23.8% and dynamic TnI changes occurred in 15.6% of the patients. The unadjusted 30-day and 1-year mortality were 19.8% and 35.9% in patients with MINS, compared with 2.7% and 11.6%, respectively, in patients without MINS (p < 0.001). After adjusting, the differences remained significant. There was no difference in mortality between patients with or without dynamic changes in TnI level.

CONCLUSION

MINS occurred frequently and was associated with increased mortality. TnI monitoring might help identify patients with increased risk of mortality and improve care. Research on preventive measures and treatments is warranted.

TRIAL REGISTRATION NUMBER AND AGENCY

ClinicalTrials.gov Identifier: NCT05933837, retrospective registered.

Evaluation of troponin I serum levels in patients with arrhythmias with and without coronary artery disease

BACKGROUND

Elevated levels of cardiac enzymes in the blood are an indicator of ongoing cardiac ischemia. Persistent tachycardia may lead to myocardial ischemia due to oxygen supply-demand mismatch.

OBJECTIVES

We sought to evaluate the probability of underlying coronary artery disease (CAD) in patients with symptomatic supraventricular (SVT) or ventricular tachyarrhythmias (VT) based on cardiac enzyme level fluctuation.

MATERIALS AND METHODS

Troponin I (TNI) levels were measured twice and coronary angiography was also performed in patients without a history of cardiovascular disease and symptomatic SVT or VT.

RESULTS

Of the 114 (group A: CAD (n = 40), group B: no CAD (n = 74)) patients eligible for the study, 34 patients in group A and 64 patients in group B had SVT, while 6 patients in group A and 10 patients in group B had VT. All patients with underlying CAD developed a significantly elevated TNI level compared to baseline, irrespective of arrhythmia type (2.02 ± 7.98 ng/ml vs. 5.64 ± 13.38, p = 0.031). In patients without CAD, TNI level was not significantly elevated compared to the baseline level, irrespective of arrhythmia type (0.34 ± 1.38 ng/ml vs. 0.48 ± 1.48 ng/ml, p = 0.158). Most patients with normal TNI levels (46 of 47 patients; 98 %) had SVT. CAD was present in 13 of 47 patients (27 %) with tachycardia, despite normal TNI levels.

CONCLUSIONS

Elevated TNI levels are not helpful to discriminate between SVT and VT. An increase in TNI level in repeated blood sampling can help identify patients with higher probability of underlying CAD. Patients with VT demonstrated higher increases in TNI levels, compared to patients with SVT.

One-Stop Plasmonic Nanocube-Excited SERS Immunoassay Platform of Multiple Cardiac Biomarkers for Rapid Screening and Progressive Tracing of Acute Myocardial Infarction

Rapid and precise acute myocardial infarction (AMI) diagnosis is essential for preventing patient death. In addition, the complementary roles of creatine kinase muscle brain (CK-MB) and cardiac troponin I (cTnI) cardiac biomarkers in the early and late stages of AMI demand their simultaneous detection, which is difficult to implement using conventional fluorescence and electrochemical technologies. Here, a nanotechnology-based one-stop immuno-surface-enhanced Raman scattering (SERS) detection platform is reported for multiple cardiac indicators for the rapid screening and progressive tracing of AMI events. Optimal SERS is achieved using optical property-based, excitation wavelength-optimized, and high-yield anisotropic plasmonic gold nanocubes. Optimal immunoassay reaction efficiencies are achieved by increasing immobilized antibodies. Multiple simultaneous detection strategies are implemented by incorporating two different Raman reports with narrow wavenumbers corresponding to two indicators and by establishing a computational SERS mapping process to accurately detect their concentrations, irrespective of multiple enzymes in the human serum. The SERS platform precisely estimated AMI onset and progressive timing in human serum and made rapid AMI identification feasible using a portable Raman spectrometer. This integrated platform is hypothesized to significantly contribute to emergency medicine and forensic science by providing timely treatment and observation.

Evaluation of the analytical and clinical performance of a new high-sensitivity cardiac troponin I assay: hs-cTnI (CLIA) assay

OBJECTIVES

Cardiac troponin (cTn) is the key biomarker for diagnosis of acute coronary syndrome (ACS). We performed a complete assessment of the high-sensitivity cardiac troponin I (hs-cTnI) (CLIA) assay on the analytical performance and clinical diagnostic performance, which was compared with Abbott ARCHITECT hs-cTnI assay.

METHODS

Sex-specific 99th percentile upper reference limits (URLs) were determined from a healthy population of 424 males and 408 females. High-sensitivity performance was assessed by examining the imprecision at sex-specific URLs and the detectable results above LoD in a cohort of healthy population. The diagnostic performance of the hs-cTnI (CLIA) assay was validated in a population of 934 patients with suspected ACS.

RESULTS

The 99th percentile URLs were 15.3 ng/L for female, 31.3 ng/L for male and 24.2 ng/L for overall population. The total imprecision near the sex-specific 99th percentile URLs were <5 %. 76.74 % of females, 97.12 % of males and 86.69 % of overall population had cTnI values exceeding the LoD, which met the criteria of high-sensitivity troponin assay. No cross-reactivity or interference was identified. The diagnostic sensitivity, specificity, PPV, NPV, and AUC of hs-cTnI (CLIA) assay were 97.97 , 90.70, 79.02, 99.21 % and 0.9885, respectively, which were comparable to ARCHITECT hs-cTnI assay.

CONCLUSIONS

hs-cTnI (CLIA) assay is a high-sensitivity troponin I method with high precision, sensitivity and specificity. The clinical diagnostic performance of hs-cTnI (CLIA) is comparable to the established ARCHITECT hs-cTnI assay. Mindray's hs-cTnI (CLIA) assay is an attractive alternative for diagnosis of myocardial infarction with a high level of accuracy and safety.

Ultrasensitive Upconversion Nanoparticle Immunoassay for Human Serum Cardiac Troponin I Detection Achieved with Resonant Waveguide Grating

Selective detection of biomarkers at low concentrations in blood is crucial for the clinical diagnosis of many diseases but remains challenging. In this work, we aimed to develop an ultrasensitive immunoassay that can detect biomarkers in serum with an attomolar limit of detection (LOD). We proposed a sandwich-type heterogeneous immunosensor in a 3 × 3 well array format by integrating a resonant waveguide grating (RWG) substrate with upconversion nanoparticles (UCNPs). UCNPs were used to label a target biomarker captured by capture antibody molecules immobilized on the surface of the RWG substrate, and the RWG substrate was used to enhance the upconversion luminescence (UCL) of UCNPs through excitation resonance. The LOD of the immunosensor was greatly reduced due to the increased UCL of UCNPs and the reduction of nonspecific adsorption of detection antibody-conjugated UCNPs on the RWG substrate surface by coating the RWG substrate surface with a carboxymethyl dextran layer. The immunosensor exhibited an extremely low LOD [0.24 fg/mL (9.1 aM)] and wide detection range (1 fg/mL to 100 pg/mL) in the detection of cardiac troponin I (cTnI). The cTnI concentrations in human serum samples collected at different times during cyclophosphamide, epirubicin, and 5-fluorouracil (CEF) chemotherapy in a breast cancer patient were measured by an immunosensor, and the results showed that the CEF chemotherapy did cause cardiotoxicity in the patient. Having a higher number of wells in such an array-based biosensor, the sensor can be developed as a high-throughput diagnostic tool for clinically important biomarkers.

Hemodialysis and biomarkers of myocardial infarction - a cohort study

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Portable microfluidic plasmonic chip for fast real-time cardiac troponin I biomarker thermoplasmonic detection

Acute myocardial infarction is one of the most serious cardiovascular pathologies, impacting patients' long-term outcomes and health systems worldwide. Significant effort is directed toward the development of biosensing technologies, which are able to efficiently and accurately detect an early rise of cardiac troponin levels, the gold standard in detecting myocardial injury. In this context, this work aims to develop a microfluidic plasmonic chip for the fast and accurate real-time detection of the cardiac troponin I biomarker (cTnI) via three complementary detection techniques using portable equipment. Furthermore, the study focuses on providing a better understanding of the thermoplasmonic biosensing mechanism taking advantage of the intrinsic photothermal properties of gold nanoparticles. Specifically, a plasmonic nanoplatform based on immobilized gold nanobipyramids was fabricated, exhibiting optical and thermoplasmonic properties that promote, based on a sandwich-like immunoassay, the "proof-of-concept" multimodal detection of cTnI via localized surface plasmon resonance, surface enhanced Raman spectroscopy and thermoplasmonic effects under simulated conditions. Furthermore, after the integration of the plasmonic nanoplatform in a microfluidic channel, the determination of cTnI in 16 real plasma samples was successfully realized via thermoplasmonic detection. The results are compared with a conventional high-sensitivity enzyme-linked immunosorbent clinical assay (ELISA), showing high sensitivity (75%) and specificity (100%) as well as fast response features (5 minutes). Thus, the proposed portable and miniaturized microfluidic plasmonic chip is successfully validated for clinical applications and transferred to clinical settings for the early diagnosis of cardiac diseases, leading towards the progress of personalized medicine.

Association between Ranolazine, Ischemic Preconditioning, and Cardioprotection in Patients Undergoing Scheduled Percutaneous Coronary Intervention

Background and Objectives: Remote ischemic preconditioning (RIPC) has demonstrated efficacy in protecting against myocardial ischemia-reperfusion injury when applied before percutaneous coronary revascularization. Ranolazine, an anti-ischemic drug, has been utilized to minimize ischemic events in chronic angina patients. However, there is a lack of trials exploring the combined effects of ranolazine pretreatment and RIPC in patients undergoing percutaneous coronary interventions (PCIs). Materials and Methods: The present study is a prospective study which enrolled 150 patients scheduled for nonemergent percutaneous coronary revascularization. Three groups were formed: a control group undergoing only PCIs, an RIPC group with RIPC applied to either upper limb before the PCI (preconditioning group), and a group with RIPC before the PCI along with prior ranolazine treatment for stable angina (ranolazine group). Statistical analyses, including ANOVAs and Kruskal-Wallis tests, were conducted, with the Bonferroni correction for type I errors. A repeated-measures ANOVA assessed the changes in serum enzyme levels (SGOT, LDH, CRP, CPK, CK-MB, troponin I) over the follow-up. Statistical significance was set at p < 0.05. Results: The ranolazine group showed (A) significantly lower troponin I level increases compared to the control group for up to 24 h, (B) significantly lower CPK levels after 4, 10, and 24 h compared to the preconditioning group (p = 0.020, p = 0.020, and p = 0.019, respectively) and significantly lower CPK levels compared to the control group after 10 h (p = 0.050), and (C) significantly lower CK-MB levels after 10 h compared to the control group (p = 0.050). Conclusions: This study suggests that combining RIPC before scheduled coronary procedures with ranolazine pretreatment may be linked to reduced ischemia induction, as evidenced by lower myocardial enzyme levels.

Hybridization chain reaction-enhanced electrochemically mediated ATRP coupling high-efficient magnetic separation for electrochemical aptasensing of cardiac troponin I

The sensitive and accurate detection of cardiac troponin I (cTnI) as a gold biomarker for cardiovascular diseases at an early stage is crucial but has long been a challenge. In this study, we presented such an electrochemical (EC) aptasensor by combining hybridization chain reaction (HCR)-enhanced electrochemically mediated atom transfer radical polymerization (eATRP) amplification with high-efficient separation of magnetic beads (MBs). Aptamer-modified MBs empowered effective recognition and separation of cTnI from complex samples with high specificity. The specific binding of cTnI and aptamer could release triggered DNA (T-DNA) into solution to drive an HCR process, which produced plentiful active sites for eATRP initiators labeling followed by initiating eATRP process. With the development of eATRP, a great many of electroactive polymer probes were continually in situ formed to generate amplified current output for signal enhancement. Compared to no amplification, HCR-enhanced eATRP promoted the signals by ∼10-fold, greatly improving detection sensitivity for low-abundant cTnI analysis. Integrating MBs as capture carriers with HCR-enhanced eATRP as amplification strategy, this EC aptasensor achieved a low detection limit of 10.9 fg/mL for cTnI detection. Furthermore, the reliable detectability and anti-interference were confirmed in serum samples, indicating its promising application toward early diagnosis of cardiovascular diseases.

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.

A SERS substrate based on perovskite quantum dots and graphene for the determination of cardiac troponin I

Noble metal has always been used as a preferred base for SERS substrate. However, the preparation cost of such materials is trully high. Therefore, many researchers have begun to search for succedanea which cost were lower. In this work, CsPbBr3@ZIF-8 was synthesized by in-situ reduction method and combined with graphene nanosheets to construct a SERS substrate. The SERS performance of this substrate could be further enhanced by the synergistic effect of perovskite quantum dots and graphene. Base on this material, a sensitive SERS strategy composed of CsPbBr3@ZIF-8@G, antibody, and Bradford method was developed for the quantitative determination of cardiac troponin I (cTnI) in human serum. It's worth noting that the sensitivity and accuracy of this method could approach the level of other SERS methods using noble metals. The "reverse"-SERS method could improve the uniformity and stability of detection platform obviously. The detection range of this method was 0.01-100 ng/mL, and the estimated detection of limit (LOD) was 4.7 pg/mL. The recovery rate of this method range was between 93.1 % and 104.8 %, and RSD range was between 4.47 % and 7.06 %.