Troponin assay use in the emergency department for management of patients with potential acute coronary syndrome: current use and future directions

Performance analysis considering endpoints for three accelerated diagnostic protocols for chest pain

INTRODUCTION

The modified accelerated diagnostic protocol (ADP) to assess patients with chest pain symptoms using troponin as the only biomarker (mADAPT), the History, ECG, Age, Risk factors, and Troponin (HEART) pathway, and the Emergency Department Assessment of Chest Pain Rule (EDACS)-ADP, are the three most well-known ADPs for patients with chest pain. These ADPs define major adverse cardiac event (MACE) as components of acute myocardial infarction, revascularization, and death; unstable angina is not included as an endpoint.

METHODS

We performed a single-center prospective observational study comparing the performance of these 3 ADPs for patients with 30-day MACE with and without unstable angina. We hypothesized that these ADPs will have high sensitivities for MACE without unstable angina, a definition used for score derivation studies. However, when unstable angina is included in the MACE, their performances would be lower than the acceptable rate of >99% sensitivity.

RESULTS

A total of 1,214 patients were included in the analysis. When unstable angina was not included in the endpoint, sensitivities for MACE were 99.1% (95% confidence interval [CI]: 96.7-99.9%), 99.5% (95% CI: 97.4-100%), and 100% (95% CI: 98.3-100%) for mADAPT, EDACS-ADP, and HEART pathway, respectively. The HEART pathway had the highest proportion of patients classified as low risk (39.2%, 95% CI: 35.8-42.9%), followed by EDACS-ADP (31.3%, 95% CI: 28.2-34.6%) and mADAPT (29.3%, 95% CI: 26.4-32.5%). However, when unstable angina was included in the MACE, sensitivities were 96.6% (95% CI: 94.4-98.1%) for mADAPT, 97.3% (95% CI: 95.3-98.6%) for EDACS-ADP, and 97.3% (95% CI: 95.3-98.6%) for the HEART pathway, respectively. There were 15 false-negative cases with mADAPT, and 12 false-negative cases each for EDACS-ADP and HEART pathway.

CONCLUSION

All three ADPs-mADAPT, EDACS-ADP, and HEART pathway-were similarly accurate in their discriminatory performance for the risk stratification of ED patients presenting with possible ACS when unstable angina was not included in the endpoint. The HEART pathway showed the best combination of sensitivity and proportion of patients that can be classified as safe for early discharge. However, when unstable angina was added to the endpoint, all three ADPs did not show appropriate safety levels and their performances were lower than the acceptable risk of MACE.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Up-Regulation of Cell-Free MicroRNA-1 and MicroRNA-221-3p Levels in Patients with Myocardial Infarction Undergoing Coronary Angiography

Purpose: Myocardial infarction (MI), known as a multifactorial disease, remains the predominant cause of mortality and sudden deaths annually. The current study aimed to measure the expression of microRNA-1 and microRNA-221-3p in MI patients.

Methods: In the current study, 100 healthy controls (with no history of heart disease) and 200 patients with MI were selected. Patients were divided into two groups based on angiography results: normal (no significant artery stenosis) and primary percutaneous coronary intervention (primary PCI, significant artery stenosis). The levels of microRNA-1 and microRNA-221-3p were quantified using real-time quantitative polymerase chain reaction. The correlation between levels of microRNAs and the common cardiac markers were analyzed statistically.

Results: In comparison to fold change, microRNA-1 elevations were 8.5-fold in normal patients and 60-fold in patients with primary PCI; while microRNA-221-3p levels were 210- fold higher in primary PCI and 31.31-fold higher in normal cases compared with the healthy controls. Receiver operating characteristic analysis showed that the area under the curve (AUC) for circulating microRNA-1 and microRNA-221 were 0.903 and 0.958 in normal patients and 0.927 and 0.985 in primary PCI patients (p < 0.0001), respectively. Pearson correlation (ρ) analysis showed that circulation of microRNA-1 correlated with serum levels of cardiac troponin I (CTnI) (ρ =0.24), creatinine (ρ =0.34), creatinine kinase-myocardial band (CK-MB) (ρ =0.31), and microRNA-221-3p was significantly correlated with serum levels of CTnI (ρ =0.6), creatinine (ρ =0.41), and CK-MB (ρ =0.37), (P < 0.0001).

Conclusion: The study underscored the potential of microRNA-1 and microRNA-221-3p as informative biomarkers and positively correlated with artery stenosis in MI.

Prognostic Value of Cortisol Index of Endobiogeny in Acute Myocardial Infarction Patients

Background and Objectives: Serum cortisol has been extensively studied for its role during acute myocardial infarction (AMI). Reports have been inconsistent, with high and low serum cortisol associated with various clinical outcomes. Several publications claim to have developed methods to evaluate cortisol activity by using elements of complete blood count with its differential. This study aims to compare the prognostic value of the cortisol index of Endobiogeny with serum cortisol in AMI patients, and to identify if the risk of mortality in AMI patients can be more precisely assessed by using both troponin I and cortisol index than troponin I alone. Materials and methods: This prospective study included 123 consecutive patients diagnosed with AMI. Diagnostic coronary angiography and revascularization was performed for all patients. Cortisol index was measured on admission, on discharge, and after 6 months. Two year follow-up for all patients was obtained. Results: Our study shows cortisol index peaks at 7–12 h after the onset of AMI, while serum cortisol peaked within 3 h from the onset of AMI. The cortisol index is elevated at admission, then significantly decreases at discharge; furthermore, the decline to its bottom most at 6 months is observed with mean values being constantly elevated. The cortisol index on admission correlated with 24-month mortality. We established combined cut-off values of cortisol index on admission > 100 and troponin I > 1.56 μg/las a prognosticator of poor outcomes for the 24-month period. Conclusions: The cortisol index derived from the global living systems theory of Endobiogeny is more predictive of mortality than serum cortisol. Moreover, a combined assessment of cortisol index and Troponin I during AMI offers more accurate risk stratification of mortality risk than troponin alone.

Serum biomarker discovery related to pathogenesis in acute coronary syndrome by proteomic approach

Acute coronary syndrome (ACS) results from inadequate supply of blood flow from the coronary arteries to the heart or ischemia. ACS has an extremely high morbidity and mortality. The levels of biomarkers currently used for detection of ACS also increase in response to myocardial necrosis and other diseases and are not elevated immediately after symptoms appear, thus limiting their diagnostic capacity. Therefore, we aimed to discover new ACS diagnostic biomarkers with high sensitivity and specificity that are specifically related to ACS pathogenesis. Sera from 50 patients with ACS and healthy controls (discovery cohort) each were analyzed using mass spectrometry (MS) to identify differentially expressed proteins, and protein candidates were evaluated as ACS biomarkers in 120 people in each group (validation cohort). α-1-acid glycoprotein 1 (AGP1), complement C5 (C5), leucine-rich α-2-glycoprotein (LRG), and vitronectin (VN) were identified as biomarkers whose levels increase and gelsolin (GSN) as a biomarker whose levels decrease in patients with ACS. We concluded that these biomarkers are associated with the pathogenesis of ACS and can predict the onset of ACS prior to the appearance of necrotic biomarkers.

Impact of more conservative European Society of Cardiology guidelines on the management of patients with acute chest pain

OBJECTIVE

Early diagnosis or rule-out of acute coronary syndrome (ACS) is a key competence of emergency medicine. Changes in the NSTE-ACS guidelines of the European Society of Cardiology (ESC) in 2015 and 2020 both warranted a henceforth more conservative approach regarding high-sensitivity troponin t (hsTnt) testing. We aimed to assess the impact of more conservative guidelines on the frequency of early rule-out and prolonged observation with repeated hsTnt testing at a high-volume tertiary care emergency department.

PATIENTS AND METHODS

We conducted a pre- and post-changeover analysis 3 months before and 3 months after transition from less (hsTnt cut-off 30 ng/L, 3-hour rule-out) to more conservative (hsTnt cut-off 14 ng/L, 1-hour rule-out) guidelines in 2015, comparing proportions of patients requiring repeated testing.

RESULTS

We included 5442 cases of symptoms suspicious of acute cardiac origin (3451 before, 1991 after, 2370 (44%) female, age 55 (SD 19) years). The proportion of patients fulfilling early-rule out criteria decreased from 68% (2348 patients) before to 60% (1195 patients) with the 2015 guidelines (P < .01). Those requiring repeated testing significantly (P < .01) increased from 22% (743 patients) to 25% (494 patients). Positive results in repeated testing significantly (P = .02) decreased from 43% (320 patients) to 37% (181 patients). Invasive diagnostics were performed in 91 patients (2.6%) before and in 75 patients (3.8%) after (P = .02) the guideline revision.

CONCLUSION

The implementation of the more conservative 2015 ESC guidelines led to a minor rise in prolonged observations because of an increase in negative repeated testing and to an increase in invasive procedures.

Differential diagnostic factors of type 1 and type 2 myocardial infarction in patients with elevated cardiac troponin levels

Objective

Emergency physicians experience difficulty in determining the disposition of patients with elevated troponin I levels using emergency room tests. In this study, we aimed to investigate factors that could discriminate between the occurrence of type 1 myocardial infarction (T1MI) and type 2 myocardial infarction (T2MI) in patients with elevated troponin I levels.

Methods

Patients admitted to the emergency department between January 1, 2017 and June 30, 2017 with elevated troponin I levels who underwent subsequent cardiac biomarker testing were included. Samples for baseline blood tests, such as cardiac biomarker levels, were collected within approximately 10 minutes of admission. Electrocardiogram, transthoracic echocardiography, and percutaneous coronary intervention results were retrospectively examined via patient report and chart reviews.

Results

During the study period, 169 of 234 (72%) patients were diagnosed with T2MI and 65 (28%) were diagnosed with T1MI. Among various factors, typical chest pain (odds ratio [OR], 4.40; 95% confidence interval [CI], 1.46 to 13.24; P=0.008), high troponin I levels (OR, 1.50; 95% CI, 1.19 to 1.90; P<0.001), high cholesterol (OR, 1.01; 95% CI, 1.00 to 1.02; P=0.008), and low D-dimer levels (OR, 0.87; 95% CI, 0.77 to 0.98; P=0.027) were significantly associated with T1MI incidence.

Conclusion

Our findings in this study indicate that typical chest pain, high levels of troponin I and cholesterol, and low levels of D-dimer were associated with the diagnosis of T1MI. Further studies are suggested to determine the cut-off values for accurate diagnosis of T1MI in the ED.

Biometric and Psychometric Remote Monitoring and Cardiovascular Risk Biomarkers in Ischemic Heart Disease

Background Patients with stable ischemic heart disease represent a heterogeneous population at variable risk for major adverse cardiac events (MACE). Because MACE typically occurs outside the hospital, we studied whether biometric and psychometric remote patient monitoring are associated with MACE risk biomarkers. Methods and Results In 198 patients with stable ischemic heart disease (mean age 65±11 years, 60% women), we evaluated baseline measures, including biometric (FitBit 2) and psychometric (acquired via smartphone-administered patient-reported outcomes) remote monitoring, in the PRE-MACE (Prediction, Risk, and Evaluation of Major Adverse Cardiac Events) study. In multivariable adjusted regression analyses, we examined the association of these measures with biomarkers of MACE risk, including NT-proBNP (N-terminal pro-b-type natriuretic peptide), u-hs-cTnI (ultra-high sensitivity cardiac-specific troponin I), and hs-CRP (high-sensitivity C-reactive) protein. Both biometric and psychometric measures were associated with NT-proBNP. Specifically, step count, heart rate, physical activity, global health score, and physical function score were all inversely related, whereas physical limitation score was directly related (P≤0.05 for all). However, only biometric measures (step count and heart rate) were associated with u-hs-cTnI (inversely related, P<0.05), while only the psychometric measures of physical limitation were associated with hs-CRP (directly related, P≤0.05). Conclusions In stable ischemic heart disease patients, remotely monitored measures were associated with MACE risk biomarkers. Both biometric and psychometric measures were related to NT-proBNP. In contrast, biometric measures were uniquely related to u-hs-cTnI, while psychometric indices were uniquely related to hs-CRP. Further investigation could assess the predictive value of these metrics for MACE in ischemic heart disease.

Troponin Levels Relate to CRP Concentrations in Patients With NAFLD on Maintenance Haemodialysis: A Retrospective Study

Introduction

Several studies have shown that high sensitivity cardiac troponin (hs-cTnT) levels are elevated in patients suffering from end-stage renal disease (ESRD), even in the absence of clinical signs and instrumental features of symptomatic acute coronary syndrome (ACS). In patients undergoing haemodialysis because of ESRD, nephrologists bear witness to this increase, whose origin and clinical impact are not yet well defined.

Methods

By a retrospective study, we evaluated data from records of 70 patients with ESRD on haemodialysis, all of them with a history of NAFLD, not suffering for at least 3 months from symptomatic angina and without a history of ischemic heart disease in the same period.

Results

Hs-cTnT and C-reactive protein (CRP) levels both increased and were correlated, rho = 0.34, P = 0.004. The correlation coefficient between troponin and age was significant, rho = 0.47, P = 0.0001. Serum concentrations of hs-cTnT for the whole population were positively predicted by CRP levels, P = 0.004. On separation of the population by gender, significant correlation between hs-cTnT and CRP was not found in women and was only present in men, P = 0.66 and P = 0.000, respectively.

Discussion

The assessment of hs-cTnT levels could represent a biological marker in particular subgroups of haemodialysis patients, especially for male patients with higher CRP, those at greater risk of silent myocardial ischemia and future major adverse cardiac events.

Conclusions

The evaluation of hs-cTnT in haemodialysed patients with NAFLD could indicate that men with higher CRP should undergo close monitoring in order to adopt specific therapy.

Non-coronary predictors of elevated high-sensitive cardiac troponin T (hs-cTnT) levels in an unselected emergency patient cohort

BACKGROUND

Aim of this study was to evaluate the predictors of hs-cTnT in a non-ACS patient cohort admitted to the emergency department.

HYPOTHESIS

Atrial fibrillation and hypertension may not always be sufficient for elevation for hs-cTnT.

METHODS

We performed a retrospective, single center study encompassing in total 1003 patients. Individuals were retrospectively divided in ACS- and non-ACS patients by two independent investigators reviewing the medical records. In order to identify predictors of hs-cTnT elevation hazard ratios were calculated for age, gender, vital signs, cardiovascular risk factors, LVEF, serum levels of CRP, hemoglobin, and creatinine. Elevation of hs-cTnT was defined by exceeding 14 ng/L (upper reference limit [URL]).

RESULTS

About 987 patients were included while 25 patients were excluded because of missing data. 307 patients (31.4%) met the current guideline requirements of diagnosing an ACS, whereas 671 patients (68.6%) were hospitalized with excluded ACS. In the multivariate analysis age, anemia, CRP, creatinine, and reduced systolic left ventricular ejection fraction were independent predictors of elevated troponin T levels in the non-ACS group. However, hypertensive systolic blood pressure, atrial fibrillation and tachycardia were not predictive for Troponin T elevation in non-ACS patients in this multivariate analysis.

CONCLUSIONS

In an unselected, non-ACS patient cohort age, chronic renal failure, inflammatory state, and reduced left ventricular systolic function were associated with hs-cTnT levels above the upper reference limit. Rather, often supposed predictors as atrial fibrillation, hypertension, and tachycardia cannot sufficiently explain increased hs-cTnT in our study. Hence, further studies are needed to assess whether isolated hypertension, tachycardia, or atrial fibrillation sufficiently explain elevated hs-cTnT.