MnO2 nanosheet quenched thulium doped photon-up conversion luminescent immunoprobe for the 'turn-on' detection of cardiac troponin T

A "turn-on" photon up conversion nano couple based on NaYF4: Yb, Tm UCNPs quenched with MnO2 nanosheet was developed for the rapid and selective detection of cTnT. Herein, MnO2 nanosheet hold on the surface of Antibody cTnT (Ab-cTnT) conjugated blue emitting up conversion nanoprobe (λem at 475 nm), which leads to quenching of fluorescence due to energy transfer from photon up conversion nanoparticles to MnO2 nanosheets. On introducing cTnT antigen to the system, the energy transfer process is hindered due to strong antigen -antibody interface on the surface. This in turn, influences the nano-couples positions and effectively separates up conversion nanoprobe from MnO2 nanosheets surface resulting in restriction to energy transfer process enabling fluorescence recovery. The developed probe shows a linear response towards cTnT in the range of 0.16-2.77 ng/mL with a Limit of Detection (LoD) of 0.025 ng/mL. The practical feasibility of the nanoprobe is performed with possible coexisting biomolecules. Biological study in human blood serum samples exhibited sufficient recovery percentage in the range of 92-103 % is obtained.

[False positive on macrotroponin]

The determination of I and T subunits of cardiac troponin isoforms are the biochemical gold standard for the detection of myocardial distress. The advent of so-called highly sensitive measurements has optimized the diagnosis of acute coronary syndromes at the cost of making the diagnostic approach more complex and increasing sensitivity to analytical interference. This article presents a case of macrotroponinemia, characterized by circulating IgG-troponin T immunocomplexes, in order to raise prescribers' awareness of the critical interpretation of high and persistent cardiac troponin values.

Improvement of Emergency Department Chest Pain Evaluation Using Hs-cTnT and a Risk Stratification Pathway

BACKGROUND

Chest pain is among the most common reasons for presentation to the emergency department (ED) worldwide. Additional studies on most cost-effective ways of differentiating serious vs. benign causes of chest pain are needed.

OBJECTIVES

Our study aimed to evaluate the effectiveness of a novel risk stratification pathway utilizing 5th generation high-sensitivity cardiac troponin T assay (Hs-cTnT) and HEART score (History, Electrocardiogram, Age, Risk factors, Troponin) in assessing nontraumatic chest pain patients in reducing ED resource utilization.

METHODS

A retrospective chart review was performed 6 months prior to and after the implementation of a novel risk stratification pathway that combined hs-cTnT with HEART score to guide evaluation of adult patients presenting with nontraumatic chest pain at a large academic quaternary care ED. Primary outcome was ED length of stay (LOS); secondary outcomes included cardiology consult rates, admission rates, number of ED boarders, and number of eloped patients.

RESULTS

A total of 1707 patients and 1529 patients were included pre- and postimplementation, respectively. Median overall ED LOS decreased from 317 to 286 min, an absolute reduction of 31 min (95% confidence interval 22-41 min), after pathway implementation (p < 0.001). Furthermore, cardiology consult rate decreased from 26.9% to 16.0% (p < 0.0001), rate of admission decreased from 30.1% to 22.7% (p < 0.0001), and number of ED boarders as a proportion of all nontraumatic chest pain patients decreased from 25.13% preimplementation to 18.63% postimplementation (p < 0.0001).

CONCLUSIONS

Implementation of our novel chest pain pathway improved numerous ED throughput metrics in the evaluation of nontraumatic chest pain patients.

Direct Comparison of the European Society of Cardiology 0/1-Hour Vs. 0/2-Hour Algorithms in Patients with Acute Chest Pain

BACKGROUND

The recent guidelines from the European Society of Cardiology recommends using high-sensitivity cardiac troponin (hs-cTn) in either 0/1-h or 0/2-h algorithms to identify or rule out acute myocardial infarction (AMI). Several studies have reported good diagnostic accuracy with both algorithms, but few have compared the algorithms directly.

OBJECTIVE

We aimed to compare the diagnostic accuracy of the algorithms head-to-head, in the same patients.

METHODS

This was a secondary analysis of data from a prospective observational study; 1167 consecutive patients presenting with chest pain to the emergency department at Skåne University Hospital (Lund, Sweden) were enrolled. Only patients with a hs-cTnT sample at presentation AND after 1 AND 2 h were included in the analysis. We compared sensitivity, specificity, and negative (NPV) and positive predictive value (PPV). The primary outcome was index visit AMI.

RESULTS

A total of 710 patients were included, of whom 56 (7.9%) had AMI. Both algorithms had a sensitivity of 98.2% and an NPV of 99.8% for ruling out AMI, but the 0/2-h algorithm ruled out significantly more patients (69.3% vs. 66.2%, p < 0.001). For rule-in, the 0/2-h algorithm had higher PPV (73.4% vs. 65.2%) and slightly better specificity (97.4% vs. 96.3%, p = 0.016) than the 0/1-h algorithm.

CONCLUSION

Both algorithms had good diagnostic accuracy, with a slight advantage for the 0/2-h algorithm. Which algorithm to implement may thus depend on practical issues such as the ability to exploit the theoretical time saved with the 0/1-h algorithm. Further studies comparing the algorithms in combination with electrocardiography, history, or risk scores are needed.

To rule-in, or not to falsely rule-out, that is the question: evaluation of hs-cTnT EQA performance in light of the ESC-2020 guideline

OBJECTIVES

To accurately evaluate non-ST-elevated acute cardiac syndrome (NSTE-ACS), the quality of high-sensitive cardiac troponin (hs-cTn) assays is of vital importance. The 2020 revision of the NSTE-ACS guideline includes clinical decision-limits (CDL's) to both rule-in and rule-out NSTE-ACS for most commercially available platforms, providing both 0/1 h and 0/2 h delta limits. Our study evaluated whether laboratories are able to meet the analytical performance specifications for imprecision (APS) for hs-cTnT.

METHODS

Results from external quality assurance (EQA) in commutable samples were used to evaluate the current and historic performance of analyzers. The performance of analyzers that either passed or failed to comply with 0/1 h-APS were used on a real-world dataset of first hs-cTnT-values to simulate 10.000 samples of t=0, t=1 and t=2 h values with multiple delta's for all relevant CDL's. We compared the simulated values to the input values to obtain the percentage of aberrant results simulated.

RESULTS

The majority of analyzers complies with APS for rule-in in 2022 (0/1 h: 90.4 % and 0/2 h: 100 %), compliance for the 0/1 h rule-out is still far from optimal (0/1 h: 30.7 %, 0/2 h: 75.4 %), with improving compliance over the past years (rule-in p=<0.0001, rule-out p=0.011, χ2). Whilst 0/1 h-APS-passing analyzers have a minute risk to falsely rule-out patients whom should be ruled-in (0.0001 %), failing performance increases this risk to 2.1 % upon using 0/1 h CDL's. Here, adopting 0/2 h CDL's is favorable (0.01 %).

CONCLUSIONS

Laboratories that fail to meet hs-cTnT 0/1 h-APS should improve their performance to the required and achievable level. Until performance is reached clinics should adopt the 0/2 h CDL's.

The use of cardiac troponins and B-type natriuretic peptide in COVID-19

Coronavirus disease 2019 (COVID-19) is still challenging health care systems worldwide. Over time, it has become clear that respiratory disease is not the only important entity as critically ill patients are also more prone to develop complications, such as acute cardiac injury. Despite extensive research, the mainstay of treatment still relies on supportive care and targeted therapy of these complications. The development of a prognostic model which helps clinicians to diverge patients to an appropriate level of care is thus crucial. As a result, several prognostic markers have been studied in the past few months. Among them are the cardiac biomarkers, especially cardiac troponins T/I and brain natriuretic peptide, which seem to have important prognostic values as several reports have confirmed their strong association with adverse clinical outcomes and death. The use of these biomarkers as part of a prognostic tool could potentially result in more precise risk stratification of COVID-19 patients and divergence to an adequate level of care. However, several caveats persist causing international guidelines to still recommend in favour of a more conservative approach to cardiac biomarker testing for prognostic purposes.

Dexamethasone is associated with early deaths in light chain amyloidosis patients with severe cardiac involvement

Background

Cardiac light chain amyloidosis (AL-CA) patients often die within three months of starting chemotherapy. Chemotherapy for non-immunoglobulin M gammopathy with AL-CA frequently includes bortezomib (Bor), cyclophosphamide (Cy), and dexamethasone (D). We previously reported that NT-ProBNP levels can double within 24h of dexamethasone administration, suggesting a deleterious impact on cardiac function. In this study, we evaluate the role of dexamethasone in early cardiovascular mortality during treatment.

Methods and findings

We retrospectively assessed 100 de novo cardiac AL patients (62% male, mean age 68 years) treated at our institute between 2009 and 2018 following three chemotherapy regimens: CyBorDComb (all initiated on day 1; 34 patients), DCyBorSeq (D, day 1; Cy, day 8; Bor, day 15; 17 patients), and CyBorDSeq (Cy, day 1; Bor, day 8; D, day 15; 49 patients). The primary endpoint was cardiovascular mortality and cardiac transplantation at days 22 and 455. At day 22, mortality was 20.6% with CyBorDComb, 23.5% with DCyBorSeq, and 0% with CyBorDSeq (p = 0.003). At day 455, mortality was not significantly different between regimens (p = 0.195). Acute toxicity of dexamethasone was evaluated on myocardial function using a rat model of isolated perfused heart. Administration of dexamethasone induced a decrease in left ventricular myocardium contractility and relaxation (p<0.05), supporting a potential negative inotropic effect of dexamethasone in AL-CA patients with severe cardiac involvement.

Conclusion

Delaying dexamethasone during the first chemotherapy cycle reduces the number of early deaths without extending survival. It is clear that dexamethasone is beneficial in the long-term treatment of patients with AL-CA. However, the initial introduction of dexamethasone during treatment is critical, but may be associated with early cardiac deaths in severe CA. Thus, it is important to consider the dosage and timing of dexamethasone introduction on a patient-severity basis. The impact of dexamethasone in the treatment of AL-CA needs further investigation.

No difference in biomarkers of ischemic heart injury and heart failure in patients with COVID-19 who received treatment with chloroquine phosphate and those who did not

Background

Chloroquine was promoted as a COVID-19 therapeutic early in the pandemic. Most countries have since discontinued the use of chloroquine due to lack of evidence of any benefit and the risk of severe adverse events. The primary aim of this study was to examine if administering chloroquine during COVID-19 imposed an increased risk of ischemic heart injury or heart failure.

Methods

Medical records, laboratory findings, and electrocardiograms of patients with COVID-19 who were treated with 500 mg chloroquine phosphate daily and controls not treated with chloroquine were reviewed retrospectively. Controls were matched in age and severity of disease.

Results

We included 20 patients receiving chloroquine (500 mg twice daily) for an average of five days, and 40 controls. The groups were comparable regarding demographics and biochemical analyses including C-reactive protein, thrombocytes, and creatinine. There were no statistically significant differences in cardiac biomarkers or in electrocardiograms. Median troponin T was 10,8 ng/L in the study group and 17.9 ng/L in the control group, whereas median NT-proBNP was 399 ng/L in patients receiving chloroquine and 349 ng/L in the controls.

Conclusions

We found no increased risk of ischemic heart injury or heart failure as a result of administering chloroquine. However, the use of chloroquine to treat COVID-19 outside of clinical trials is not recommended, considering the lack of evidence of its effectiveness, as well as the elevated risk of fatal arrythmias.

Undetectable High-Sensitivity Troponin T as a Gatekeeper for Coronary Computed Tomography Angiography in Patients Suspected of Acute Coronary Syndrome

OBJECTIVES

The aim of this study was to characterize the safety and efficiency of a strategy employing the limit of detection (LoD) of high-sensitivity troponin T (hs-TnT) as a gatekeeper for coronary computed tomography angiography (CCTA) in suspected acute coronary syndrome (ACS) patients in the emergency department (ED).

METHODS

We included suspected ACS patients who underwent CCTA and were evaluated with hs-TnT. Patients were categorized as below the LoD and at or above the LoD. The primary outcome was 30-day major adverse cardiac events (MACEs), defined as all-cause mortality, ACS, or coronary revascularization.

RESULTS

The study population consisted of 177 patients (mean age 55 ± 10 years, 50.3% women), and 16 (9.0%) patients reached the primary outcome. None of the patients died, while 13 had an adjudicated diagnosis of ACS, and 3 underwent elective coronary revascularization. There were 77 patients (44%) with an hs-TnT value below the LoD (MACEs; n = 1 [1.3%]) and 100 (56%) with at or above the LoD levels (MACEs; n = 15 [15%]). None of 67 patients with an hs-TnT value below the LoD and <50% stenosis on CCTA experienced MACEs. Out of the 10 patients with an hs-TnT value below the LoD and ≥50% stenosis on CCTA, 1 patient underwent elective percutaneous coronary revascularization. In patients with an hs-TnT value at or above the LoD, 74 patients had <50% stenosis on CCTA, and 2 patients (3%) were diagnosed with myocardial infarction without obstructive coronary artery disease confirmed on invasive angiography. Thirteen (50%) patients with an hs-TnT value at or above the LoD and ≥50% stenosis on CCTA experienced MACEs (11 ACS and 2 elective percutaneous coronary revascularizations).

CONCLUSION

Our findings support that implementing the LoD of hs-TnT as a gatekeeper may reduce the need for CCTA in suspected ACS patients in the ED.

Fluorescent hollow ZrO2@CdTe nanoparticles-based lateral flow assay for simultaneous detection of C-reactive protein and troponin T

Highly fluorescent hollow ZrO₂@CdTe nanoparticles (NPs) were synthesized efficiently via the hydrothermal method. By changing the hydrothermal time of ZrO₂@CdTe NP, the peaks of fluorescence spectra measured at fluorescent excitation of 330 nm were at 540 nm, 590 nm, and 640 nm, respectively. Hollow ZrO₂ NPs have a uniform core-shell structure with the size of 178 ± 10 nm and shell of 19 ± 4 nm. The as-prepared yellow-ZrO₂@CdTe NPs were used to develop lateral flow assay (LFA) for the sensitive and qualitative detection of C-reactive protein (CRP). The visual limit of detection of the LFA for the CRP antigen was 1 μg/L within 20 min, which is 1000-fold lower than that of colloidal gold-based LFA. In addition, a multiplex lateral flow assay (mLFA) was developed using the as-prepared green and red-ZrO₂@CdTe NPs for the simultaneous, specific, sensitive, and qualitative detection of CRP and troponin T (cTnT). The visual limits of detection of CRP and cTnT in mLFA were 10 μg/L and 0.1 mg/L, respectively. The excellent performance of ZrO₂@CdTe NPs should facilitate their application in point-of-care technology for the detection of other biomarkers.

Intraoperative blood loss may be associated with myocardial injury after non-cardiac surgery

BACKGROUND

This study aimed to evaluate the association between intraoperative blood loss and myocardial injury after non-cardiac surgery (MINS), which is a severe and common postoperative complication.

METHODS

We compared the incidence of MINS based on significant intraoperative bleeding, defined as an absolute hemoglobin level < 7 g/dL, a relative hemoglobin level less than 50% of the preoperative measurement, or need for packed red cell transfusion. We also estimated a threshold for intraoperative hemoglobin level associated with MINS.

RESULTS

We stratified a total of 15,926 non-cardiac surgical patients with intraoperative hemoglobin and postoperative cardiac troponin (cTn) measurements according to the occurrence of significant intraoperative bleeding; 13,416 (84.2%) had no significant bleeding while 2,510 (15.8%) did have significant bleeding. After an adjustment with inverse probability weighting, the incidence of MINS was higher in the significant bleeding group (35.2% vs. 16.4%; odds ratio, 1.58; 95% confidence interval, 1.43-1.75; p < 0.001). The threshold of intraoperative hemoglobin associated with MINS was estimated to be 9.9 g/dL with an area under the curve of 0.643.

CONCLUSION

Intraoperative blood loss appeared to be associated with MINS. Further studies are needed to confirm these findings.

CLINICAL REGISTRATION

The cohort was registered before patient enrollment at https://cris.nih.go.kr (KCT0004244).

Optimizing the Use of High-Sensitivity Troponin Assays for the Early Rule-out of Myocardial Infarction in Patients Presenting with Chest Pain: A Systematic Review

BACKGROUND

We assessed the accuracy and clinical effectiveness of high-sensitivity cardiac troponin (hs-cTn) assays for early rule-out of non-ST-segment elevation myocardial infarction (NSTEMI) in adults presenting with acute chest pain.

METHODS

Sixteen databases were searched to September 2019. Review methods followed published guidelines. The bivariate model was used to estimate summary sensitivity and specificity with 95% confidence intervals for meta-analyses involving 4 or more studies, otherwise random-effects logistic regression was used.

RESULTS

Thirty-seven studies (124 publications) were included in the review. The hs-cTn test strategies evaluated in the included studies were defined by the combination of 4 factors (assay, number of tests, timing of tests, and threshold concentration or change in concentration between tests). Clinical opinion indicated a minimum acceptable sensitivity of 97%. A single test at presentation using a threshold at or near the assay limit of detection could reliably rule-out NSTEMI for a range of hs-cTn assays. Serial testing strategies, which include an immediate rule-out step, increased the proportion ruled out without loss of sensitivity. Finally, serial testing strategies without an immediate rule-out step had excellent sensitivity and specificity, but at the expense of the option for immediate patient discharge.

CONCLUSION

Test strategies that comprise an initial rule-out step, based on low hs-cTn concentrations at presentation and a minimum symptom duration, and a second step for those not ruled-out that incorporates a small absolute change in hs-cTn at 1, 2, or 3 hours, produce the highest rule-out rates with a very low risk of missed NSTEMI.

PROSPERO REGISTRATION

CRD42019154716.

Type 2 Myocardial Infarction: Evolving Approaches to Diagnosis and Risk-Stratification

BACKGROUND

Type 2 myocardial infarction (T2MI) is frequently encountered in clinical practice and associated with adverse outcomes.

CONTENT

T2MI occurs most frequently due to noncoronary etiologies that alter myocardial oxygen supply and/or demand. The diagnosis of T2MI is often confused with acute nonischemic myocardial injury, in part because of difficulties in delineating the nature of symptoms and misunderstandings about disease categorization. The use of objective features of myocardial ischemia using electrocardiographic (ECG) or imaging abnormalities may facilitate more precise T2MI diagnosis. High-sensitivity cardiac troponin (hs-cTn) assays allow rapid MI diagnosis and risk stratification, yet neither maximum nor delta values facilitate differentiation of T2MI from T1MI. Several investigational biomarkers have been evaluated for T2MI, but none have robust data. There is interest in evaluating risk profiles among patients with T2MI. Clinically, the magnitude of maximum and delta cTn values as well as the presence and magnitude of ischemia on ECG or imaging is used to indicate disease severity. Scoring systems such as GRACE, TIMI, and TARRACO have been evaluated, but all have limited to modest performance, with substantial variation in time intervals used for risk-assessment and endpoints used.

SUMMARY

The diagnosis of T2MI requires biomarker evidence of acute myocardial injury and clear clinical evidence of acute myocardial ischemia without atherothrombosis. T2MIs are most often caused by noncoronary etiologies that alter myocardial oxygen supply and/or demand. They are increasingly encountered in clinical practice and associated with poor short- and long-term outcomes. Clinicians require novel biomarker or imaging approaches to facilitate diagnosis and risk-stratification.

Diagnostic value of copeptin combined with hypersensitive cardiac troponin T detection in early acute myocardial infarction: A protocol of randomized double-blind diagnostic trial

BACKGROUND

The sensitivity and specificity of the routine detection of acute myocardial infarction (AMI) in early diagnosis are not high, which can not meet the clinical needs. Copeptin combined with hypersensitive cardiac troponin T (hs-cTnT) is a new detection scheme, and its value in the early diagnosis of acute myocardial infarction is still unclear. Accordingly, the aim of this study is to evaluate the diagnostic value of copeptin combined with hypersensitive troponin T detection in early acute myocardial infarction.

METHODS

This is a prospective, randomized; double-blind diagnostic trial to investigate the diagnostic value of copeptin combined with hypersensitive troponin T detection in early acute myocardial infarction. Approved by the clinical research ethics of our hospital. Patients were randomly divided into one of 2 test protocols: (A) copeptin combined with hs-cTnT group and (B) cardiac troponin I (cTnI) group. Patients, doctors, nurses, inspectors, and data-gathering assistants were blinded to group allocation. We will focus on the sensitivity comparison of the 2 detection methods at different time periods and the sensitivity and specificity comparison of the two detection methods. Data were analyzed using the statistical software package SPSS version 25.0 (Chicago, IL).

DISCUSSION

The purpose of this study is to evaluate the diagnostic value of copeptin combined with hypersensitive cardiac troponin T detection in early acute myocardial infarction. The results of this study will establish clinical evidence for the detection of high sensitivity cardiac troponin T in the early diagnosis of acute myocardial infarction.

ETHICS AND DISSEMINATION

Private information from individuals will not be published. This systematic review also does not involve endangering participant rights. Ethical approval was not required. The results may be published in a peer-reviewed journal or disseminated at relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/6TE5Z.

Laboratory Findings Associated With Severe Illness and Mortality Among Hospitalized Individuals With Coronavirus Disease 2019 in Eastern Massachusetts

IMPORTANCE

The coronavirus disease 2019 (COVID-19) pandemic has placed unprecedented stress on health systems across the world, and reliable estimates of risk for adverse hospital outcomes are needed.

OBJECTIVE

To quantify admission laboratory and comorbidity features associated with critical illness and mortality risk across 6 Eastern Massachusetts hospitals.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of all individuals admitted to the hospital who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by polymerase chain reaction across these 6 hospitals through June 5, 2020, using hospital course, prior diagnoses, and laboratory values in emergency department and inpatient settings from 2 academic medical centers and 4 community hospitals. The data were extracted on June 11, 2020, and the analysis was conducted from June to July 2020.

EXPOSURES

SARS-CoV-2.

MAIN OUTCOMES AND MEASURES

Severe illness defined by admission to intensive care unit, mechanical ventilation, or death.

RESULTS

Of 2511 hospitalized individuals who tested positive for SARS-CoV-2 (of whom 50.9% were male, 53.9% White, and 27.0% Hispanic, with a mean [SD ]age of 62.6 [19.0] years), 215 (8.6%) were admitted to the intensive care unit, 164 (6.5%) required mechanical ventilation, and 292 (11.6%) died. L1-regression models developed in 3 of these hospitals yielded an area under the receiver operating characteristic curve of 0.807 for severe illness and 0.847 for mortality in the 3 held-out hospitals. In total, 212 of 292 deaths (72.6%) occurred in the highest-risk mortality quintile.

CONCLUSIONS AND RELEVANCE

In this cohort, specific admission laboratory studies in concert with sociodemographic features and prior diagnosis facilitated risk stratification among individuals hospitalized for COVID-19.

Using the clinical chemistry score in the emergency department to detect adverse cardiac events: a diagnostic accuracy study

BACKGROUND

The ability to rule out or in a major adverse cardiac event (MACE) in patients with suspected acute coronary syndrome at emergency department (ED) presentation would be beneficial to patient care and the health care system. The clinical chemistry score (CCS) was evaluated in this context.

METHODS

This diagnostic accuracy study evaluated 2 different ED cohorts with suspected acute coronary syndrome. For patients in cohort 1, who presented to the ED of 3 hospitals in Hamilton, Ontario, between May and August 2013, retrospective measurements were taken using the Ortho Clinical Diagnostics high-sensitivity cardiac troponin I (hs-cTnI) assay; for patients in cohort 2, who presented to the ED of the same 3 hospitals in Hamilton between November 2012 and February 2013, an ED cardiac presentation blood test panel was performed with the Abbott Diagnostics hs-cTnI assay. The sensitivity and specificity of the CCS (cut-offs of ≥ 1 and 5) and hs-cTnI alone (published cut-offs) were compared for MACE (composite of death, myocardial infarction, unstable angina, revascularization) at 30 days for both cohorts and at 90 days for cohort 2.

RESULTS

The incidence of MACE at 30 days was higher in cohort 1 (n = 1058) (19.4%, 95% confidence interval [CI] 16.8%-22.2%) than in cohort 2 (n = 5974) (14.6%, 95% CI 13.6%-15.6%). In cohort 1, a CCS of 1 or above yielded a sensitivity of 99.5% (95% CI 97.3%-99.9%). The sensitivity with an Ortho hs-cTnI cut-off of 1 ng/L or above was 91.2% (95% CI 86.5%-95.7%). The specificity of a CCS of 5 (97.8%, 95% CI 96.5%-98.7%) was higher than when the overall 99th-percentile cut-off for the Ortho hs-cTnI assay (> 11 ng/L; 90.1%, 95% CI 87.9%-92.0%) was used. A similar pattern was observed in cohort 2 at 30 days and persisted at 90 days with the Abbott hs-cTnI assay.

INTERPRETATION

The CCS derived with 2 different hs-cTnI assays and ED populations yielded higher sensitivity and specificity estimates for MACE than hs-cTnI alone. An intervention study is needed to evaluate the impact of the CCS at both the patient and hospital levels.

TRIAL REGISTRATION

ClinicalTrials.gov, no. NCT01994577.

Performance of High-Sensitivity Cardiac Troponin Assays to Reflect Comorbidity Burden and Improve Mortality Risk Stratification in Older Adults With Diabetes

OBJECTIVE

Incorporation of comorbidity burden to inform diabetes management in older adults remains challenging. High-sensitivity cardiac troponins are objective, quantifiable biomarkers that may improve risk monitoring in older adults. We assessed the associations of elevations in high-sensitivity cardiac troponin I (hs-cTnI) and T (hs-cTnT) with comorbidities and improvements in mortality risk stratification.

RESEARCH DESIGN AND METHODS

We used logistic regression to examine associations of comorbidities with elevations in either troponin (≥85th percentile) among 1,835 participants in the Atherosclerosis Risk in Communities (ARIC) Study with diabetes (ages 67-89 years, 43% male, 31% black) at visit 5 (2011-2013). We used Cox models to compare associations of high cardiac troponins with mortality across comorbidity levels.

RESULTS

Elevations in either troponin (≥9.4 ng/L for hs-cTnI, ≥25 ng/L for hs-cTnT) were associated with prevalent coronary heart disease, heart failure, chronic kidney disease, pulmonary disease, hypoglycemia, hypertension, dementia, and frailty. Over a median follow-up of 6.2 years (418 deaths), both high hs-cTnI and high hs-cTnT further stratified mortality risk beyond comorbidity levels; those with a high hs-cTnI or hs-cTnT and high comorbidity were at highest mortality risk. Even among those with low comorbidity, a high hs-cTnI (hazard ratio 3.0 [95% CI 1.7, 5.4]) or hs-cTnT (hazard ratio 3.3 [95% CI 1.8, 6.2]) was associated with elevated mortality.

CONCLUSIONS

Many comorbidities were reflected by both hs-cTnI and hs-cTnT; elevations in either of the troponins were associated with higher mortality risk beyond comorbidity burden. High-sensitivity cardiac troponins may identify older adults at high mortality risk and be useful in guiding clinical care of older adults with diabetes.

Clinical outcomes for chest pain patients discharged home from emergency departments using high-sensitivity versus conventional cardiac troponin assays

BACKGROUND

High-sensitivity cardiac troponin (hs-cTn) assays enhance detection of lower circulating troponin concentrations, but the impact on outcomes in clinical practice is unclear. Our objective was to compare outcomes of chest pain patients discharged from emergency departments (EDs) using hs-cTn and conventional troponin (cTn) assays.

METHODS

We conducted an observational study of chest pain patients aged 40-105 years who presented to an ED from April 1, 2013, to March 31, 2017, and were discharged home. We compared 30-day and 1-year outcomes of EDs that used hs-cTn versus cTn assays. The primary outcome was a composite of all-cause death, myocardial infarction or unstable angina. Comparisons were conducted with (1) no adjustment; (2) adjustment for demographic, socioeconomic, and hospital characteristics; and (3) full clinical adjustment.

RESULTS

Among the 394,910 patients, 62,138 (15.7%) were evaluated at hs-cTn EDs and 332,772 (84.3%) were evaluated at cTn EDs. Patients discharged from hs-cTn EDs were less likely to have diabetes, hypertension, or prior heart disease. At 30 days, the unadjusted primary outcome rate was lower in hs-cTn EDs (0.9% vs 1.0%, P < .001). The 30-day hazard ratios for the primary outcome were 0.84 (95% CI 0.77-0.92) for no adjustment and 0.98 (95% CI 0.88-1.08) for full adjustment. Over 1 year, patients discharged from hs-cTn EDs had significantly fewer primary outcomes (3.7% vs 4.1%, P < .001) and lower hazard ratio (0.93; 95% CI 0.89-0.98) even after full adjustment.

CONCLUSIONS

Hs-cTn testing was associated with a significantly lower adjusted hazard of myocardial infarction, angina, and all-cause hospitalization at 1 year but not 30 days.

Top-Down Proteomics Reveals Myofilament Proteoform Heterogeneity among Various Rat Skeletal Muscle Tissues

Heterogeneity in skeletal muscle contraction time, peak power output, and resistance to fatigue, among others, is necessary to accommodate the wide range of functional demands imposed on the body. Underlying this functional heterogeneity are a myriad of differences in the myofilament protein isoform expression and post-translational modifications; yet, characterizing this heterogeneity remains challenging. Herein, we have utilized top-down liquid chromatography (LC)-mass spectrometry (MS)-based proteomics to characterize myofilament proteoform heterogeneity in seven rat skeletal muscle tissues including vastus lateralis, vastus medialis, vastus intermedius, rectus femoris, soleus, gastrocnemius, and plantaris. Top-down proteomics revealed that myofilament proteoforms varied greatly across the seven different rat skeletal muscle tissues. Subsequently, we quantified and characterized myofilament proteoforms using online LC-MS. We have comprehensively characterized the fast and slow skeletal troponin I isoforms, which demonstrates the ability of top-down MS to decipher isoforms with high sequence homology. Taken together, we have shown that top-down proteomics can be used as a robust and high-throughput method to characterize the molecular heterogeneity of myofilament proteoforms from various skeletal muscle tissues.

Effect of corticosteroids on myocardial injury among patients hospitalized for community-acquired pneumonia: rationale and study design. The colosseum trial

Community-acquired pneumonia (CAP) is often complicated by elevation of cardiac troponin, a marker of myocardial injury that can be isolated or associated with myocardial infarction (MI). A retrospective study showed that corticosteroid treatment lowers the incidence of MI during the hospital stay. No data exist so far on the effect of corticosteroids on myocardial injury in CAP patients. The primary objective of the study is to evaluate if methylprednisolone is able to reduce myocardial injury, as assessed by serum high-sensitivity cardiac T Troponin (hs-cTnT), in a cohort of patients hospitalized for CAP. Secondary aims are to evaluate the potential effect of methylprednisolone on cardiovascular events during hospitalization, at 30 days from hospital admission and during 2 years' follow-up. The trial will also examine whether the potential protective effects of methylprednisolone might be due to platelet activation down-regulation. Double-blind randomized placebo-controlled trial. One hundred twenty-two eligible patients will be randomized to a week treatment with iv methylprednisolone (20 mg b.i.d) or placebo from hospital admission. Serum hs-cTnT will be measured at admission and every day until up 3 days from admission. ECG will be monitored every day until discharge. After discharge, all patients will be followed-up 2 years. This is the first clinical trial aimed at examining whether methylprednisolone treatment may reduce myocardial injury. The results of this trial may constitute the basis for conducting a larger multicenter trial aimed to evaluate the effect of corticosteroid on cardiovascular events in this setting.

Functionalized Graphene Quantum Dot Interfaced Electrochemical Detection of Cardiac Troponin I: An Antibody Free Approach

According to the World Health Organization (WHO), cardiovascular disease (CVD) is the leading cause of death in the world every year. The design and development of biosensors for the detection of CVD markers could be one of the major contributions of the scientific community to society. In this context, acetic acid functionalized graphene quantum dots (fGQDs) were used as an interface for the electrochemical detection of cardiac Troponin I (cTnI). The interaction of cTnI with fGQDs for the early diagnosis of acute myocardial infarction was investigated using cyclic voltammetry (CV) and amperometry. The carbodiimide conjugation between the N-H group of cTnI and the functionalized COOH group on GQDs enabled the detection of cTnI biomarker. The same sensing mechanism was confirmed using Fourier Transform Infrared Spectrometry (FTIR). The fGQDs modified Au electrode showed remarkable electrocatalytic oxidation of cTnI with good stability and sensitivity over a linear range of 0.17 to 3 ng mL-1 and a low detection limit of 0.02 ng mL-1. Bland-Altman plots substantiate a bias between the intra-/inter-cTnI assay and calibrated cTnI assay with 95% limits of agreement (mean difference ± 1.96 SD). The aim of this study is to describe an innovative method to detect cardiac biomarker cTnI and provide preliminary data on its diagnostic capacity. At the same time, its applicability in clinical setting will have to be validated with a significant number of samples collected from patients.

Rapid rule-out of suspected acute coronary syndrome in the Emergency Department by high-sensitivity cardiac troponin T levels at presentation

The reliability of initial high-sensitivity cardiac troponin T (hs-cTnT) under limit-of-detection in ruling-out short- and long-term acute coronary events in subjects for suspected non-ST-segment elevation acute coronary syndrome (NSTE-ACS) is not definitely settled. In a retrospective chart review analysis, 1001 subjects with hs-cTnT ≤ 14 ng/L out of 4053 subjects with hs-cTnT measured at Emergency Department (ED) presentation were recruited. The main outcome measure is fatal or non-fatal myocardial infarction (MI) within 30 days; secondary outcomes are MI or major acute coronary events (MACE) as a combination of MI or re-hospitalization for unstable angina within 1 year. In subjects with hs-cTnT < 5 ng/L [32.6% of cases, mean age 63 years (interquartile range 23)], no cases (0%, NPV 100%) had MI within 30 days, 2 cases (0.6%, NPV 99.4%) MI at 1-year, and 11 cases (3.4%, NPV 96.6%) MACE at 1-year. Patients with hs-cTnT < 5 ng/L would have benefited from a shortened decision (9.30 h and 53% overnight ED stay saved). Hs-cTnT < 5 ng/L is confirmed as safe for patients and comfortable for physicians in ruling out MI or MACE both at short and long term, suggesting that a sizable number of patients can be rapidly discharged without unnecessary diagnostic tests and ED observation.