How to use high-sensitivity cardiac troponins in acute cardiac care

Predicting Acute Myocardial Infarction with a Single Blood Draw

BACKGROUND

We desired to determine cardiac troponin (cTn) concentrations necessary to achieve a positive predictive value (PPV) of ≥75% for acute myocardial infarction (AMI) to justify immediate admission of patients to a monitored unit and, in general, early coronary angiography.

METHODS

In a prospective multicenter diagnostic study enrolling patients presenting to the emergency department with symptoms suggestive of AMI, final diagnoses were adjudicated by 2 independent cardiologists based on clinical information including cardiac imaging. cTn concentrations were measured using 5 different sensitive and high-sensitivity cTn (hs-cTn) assays in a blinded fashion at presentation and serially thereafter. The diagnostic end point was PPV for rule-in of AMI of initial cTn concentrations alone and in combination with early changes.

RESULTS

Among 3828 patients, 616 (16%) had an AMI. At presentation, 7% to 14% of patients had cTnT/I concentrations associated with a PPV of ≥75%. Adding absolute or relative changes did not significantly further increase the PPV. PPVs increased from 46.5% (95% CI, 43.6–49.4) for hs-cTnT at presentation >14 ng/L to 78.9% (95% CI, 74.7–82.5) for >52 ng/L (P < 0.001), whereas PPVs in higher hs-cTnT strata remained largely unchanged [e.g., 82.4% (95% CI, 77.5–86.7) for >80 ng/L vs 83.9% (95% CI, 76.0–90.1) for >200 ng/L (P = 0.72)]. The addition of early changes in hs-cTnT further increased the PPV up to 60 ng/L, but not for higher concentrations.

CONCLUSIONS

Serial sampling does not seem necessary for predicting AMI and concurrent decision-making in about 10% of patients, as it only marginally increases the PPV for AMI and not in a statistically or clinically significant way.

ClinicalTrials.gov Identifier

NCT00470587.

Sex-Specific Cut-Offs for High-Sensitivity Cardiac Troponin: Is Less More?

Management of patients presenting to the Emergency Department with chest pain is continuously evolving. In the setting of acute coronary syndrome, the availability of high-sensitivity cardiac troponin assays (hs-cTn) has allowed for the development of algorithms aimed at rapidly assessing the risk of an ongoing myocardial infarction. However, concerns were raised about the massive application of such a simplified approach to heterogeneous real-world populations. As a result, there is a potential risk of underdiagnosis in several clusters of patients, including women, for whom a lower threshold for hs-cTn was suggested to be more appropriate. Implementation in clinical practice of sex-tailored cut-off values for hs-cTn represents a hot topic due to the need to reduce inequality and improve diagnostic performance in females. The aim of this review is to summarize current evidence on sex-specific cut-off values of hs-cTn and their application and usefulness in clinical practice. We also offer an extensive overview of thresholds reported in literature and of the mechanisms underlying such differences among sexes, suggesting possible explanations about debated issues.

Assessment of Access hsTnI 99th percentiles upper reference limits following IFCC recommendations

BACKGROUND

The detection of an increase and/or decrease of cardiac troponin (cTnI) values, with at least one value above the 99th percentile of the upper reference limit (URL) have a central role in acute myocardial infarction (AMI) diagnosis. The employment of sex specific 99th percentile URLs and High-sensitivity (Hs) assays are recommended. We assessed sex specific 99th percentile URL for Access Hs-cTnI and AccuTnI3+ (Beckman Coulter) using European donor reference population following recent International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) recommendations.

METHODS

300 males and 300 females plasma samples were collected. Both chemiluminescent immunoenzymatic assays were performed on UniCel DxI 800 platform (Beckman Coulter).

RESULTS

For Access hsTnI, the observed sex-specific 99th percentile URLs were 5.5 (90% CI: 4.4-7.6) for females and 13.9 ng/L (90% CI: 7.4-17.4) for males. For AccuTnI+3 we could not establish them because the assay couldn't report detectable values of troponin for most of the analyzed samples.

CONCLUSION

The sex-specific 99th percentile URLs established for Access hsTnI assay were significantly lower than those declared by the manufacturer caused by the different choice of population selection, age groups and sample types: for those reasons, we maintain the 99th URLs provided by manufacturer.

Circulating microRNA-1 in the diagnosis and predicting prognosis of patients with chest pain: a prospective cohort study

Background

To investigate the early diagnostic and prognostic value of microRNA-1 in patients with acute chest pain.

Methods

This study enrolled 341 patients attacked by chest pain within 3 h, and another 100 volunteers as control group. Circulating microRNA-1 was collected and determined by real-time quantitative reverse transcription-polymerase chain reaction. The clinical follow-up period was 720 days.

Results

There were 174 patients in acute myocardial infarction (AMI) group, 167 in non-AMI group. The relative expression of microRNA-1 was significantly increased within 3 h in AMI group, and it continued rising within 12 h, lower at 24 h than that 12 h in AMI group without reperfusion therapy. Otherwise, microRNA-1 concentration was markedly low at 12 h after primary percutaneous coronary intervention in AMI group. The 95% reference range of circulating microRNA-1 was 0.171–0.653. It was significantly available for microRNA-1 to early diagnose AMI with an optimal cutoff value of 2.215 and diagnostic accuracy could be improved when combined with cardiac troponin I. It was not statistically significant for microRNA-1 to forecast future AMI but might prognose mortality of 720 days in chest pain patients. In patients with chest pain, microRNA-1 concentration was high with major adverse cardiac events within 30 days, low with high overall survival within 720 days.

Conclusions

Circulating microRNA-1 might diagnose early AMI and predict the prognosis of patients with chest pain.

Causes and prevention of postoperative myocardial injury

Over the past few years non-cardiac surgery has been recognised as a serious circulatory stress test which may trigger cardiovascular events such as myocardial infarction, in particular in patients at high risk. Detection of these postoperative cardiovascular events is difficult as clinical symptoms often go unnoticed. To improve detection, guidelines advise to perform routine postoperative assessment of cardiac troponin. Troponin elevation - or postoperative myocardial injury - can be caused by myocardial infarction. However, also non-coronary causes, such as cardiac arrhythmias, sepsis and pulmonary embolism, may play a role in a considerable number of patients with postoperative myocardial injury. It is crucial to acquire more knowledge about the underlying mechanisms of postoperative myocardial injury because effective prevention and treatment options are lacking. Preoperative administration of beta-blockers, aspirin, statins, clonidine, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, and preoperative revascularisation have all been investigated as preventive options. Of these, only statins should be considered as the initiation or reload of statins may reduce the risk of postoperative myocardial injury. There is also not enough evidence for intraoperative measures such blood pressure optimisation or intensified medical therapy once patients have developed postoperative myocardial injury. Given the impact, better preoperative identification of patients at risk of postoperative myocardial injury, for example using preoperatively measured biomarkers, would be helpful to improve cardiac optimisation.

Evaluation of analytical performance of immunoassay methods for cTnI and cTnT: From theory to practice

Current guidelines worldwide recommend cardiac troponins I (cTnI) and T (cTnT) as the biomarkers of choice for the differential diagnosis of acute coronary syndrome (ACS), and the measurement of the 99th upper reference population limit (URL) value for cardiac troponins, with an imprecision of ≤10 CV%. Measuring the 99th URL of cTnI and cTnT is a challenging analytical task due to low biomarker concentrations present in healthy subjects. Therefore, since the year 2006, several manufacturers have established new generation cTnI and cTnT immunoassays with an improved analytical sensitivity in accordance with the quality specifications described in international guidelines, the more recent of which state that only immunoassays that meet the required quality specifications should be considered "high-sensitivity" methods. For the early diagnosis of ACS, and for the stratification of cardiovascular risk in cardiac patients and the general population, high-sensitivity methods should be employed. It is therefore important for laboratory professionals and clinicians to gain a thorough understanding of the analytical performances of immunoassay methods for cTnI and cTnT, especially at low to normal concentration ranges. The aim of the present study was to analyze critical aspects related to definition, analytical performance, pathophysiological interpretations, and the clinical relevance of high-sensitivity cardiac troponin assays.

Cardiac Troponin T in Healthy Full-Term Infants

In this prospective cohort study of healthy full-term infants, we hypothesized that high-sensitivity cardiac troponin T (hs-cTnT) would be elevated in cord blood, compared with adult reference values, and that it would further increase over the first days of age. Cardiac troponin T has been shown to be significantly increased in healthy full-term newborns compared with adult reference values, but there is no established reference range. Most studies of cTnT in newborns have been performed before the introduction of high-sensitivity cTnT (hs-cTnT) assay. We conducted a study including 158 full-term newborns, at Stockholm South General Hospital. High-sensitivity cTnT was analyzed in umbilical cord blood and at 2-5 days of age. Median hs-cTnT (interquartile range) in cord blood was 34(26-44) ng/L; 99th percentile 88 ng/L. Median hs-cTnT at 2-5 days of age was 92(54-158) ng/L; 99th percentile 664 ng/L. We conclude that hs-cTnT is elevated in cord blood in healthy, full-term newborn infants compared with adult reference values, and that it increases significantly during the first days of life. Our findings further underline the need of caution when using hs-cTnT as a measurement of cardiac impact in newborns.

Cardiovascular stress biomarker assessment of middle-aged non-athlete marathon runners

Background

Cardiovascular safety of marathon running in recreational runners remains unclear. We set up this study to comprehensively evaluate the effects of a marathon run on the profile of cardiovascular stress biomarkers in connection with transthoracic echocardiography.

Design and methods

Thirty-three healthy male amateur runners, aged ≥50 years (mean age 57 ± 7) were enrolled. Venous blood samples were obtained before the marathon, just after the race, 2–4 and seven days after the marathon. Using novel single molecule counting technology we measured: plasma concentrations of high-sensitivity cardiac troponin I (hs-cTnI) and endothelin-1. N-terminal pro B-type natriuretic peptide was measured using electrochemiluminescence. Each participant had transthoracic echocardiography before and immediately after the race.

Results

We observed a sharp rise in the levels of all biomarkers after the race (all p < 0.01), which subsequently normalized after 2–4 days and stayed within normal range after seven days. Runners with intensive training programmes (>169 km/month, a median for the studied group) had lower hs-cTnI leak after the race (median 15.11 ng/ml and 31.2 ng/ml, respectively; p < 0.05). Neither transthoracic echocardiography measures of ventricles nor strain rates changed after the run. We observed a decrease in the left atrial volume index and increase in the maximal right atrial volumes (all p < 0.05). Changes in Doppler indices of diastolic function suggestive of alteration in left ventricular relaxation were observed.

Conclusions

Marathon run is associated with sharp and significant rises in the biomarkers of cardiovascular stress. The profile of these changes, however, along with echocardiographic parameters, does not suggest irreversible myocardial damage.

Use of High-Sensitivity Cardiac Troponin for the Exclusion of Inducible Myocardial Ischemia: A Cohort Study

BACKGROUND

Many patients with coronary artery disease (CAD) are routinely referred for surveillance stress testing despite recommendations against it.

OBJECTIVE

To determine whether low levels of resting high-sensitivity cardiac troponin I (hs-cTnI) can identify persons without inducible myocardial ischemia.

DESIGN

Observational study.

SETTING

A university-affiliated hospital network.

PATIENTS

Persons with stable CAD: 589 in the derivation group and 118 in the validation cohort.

MEASUREMENTS

Presence of inducible myocardial ischemia was determined by myocardial perfusion imaging with technetium-99m single-photon emission computed tomography during either treadmill or pharmacologic stress testing. Resting plasma hs-cTnI was measured within 1 week of the stress test, and the negative predictive value (NPV) for inducible ischemia was calculated. The derivation cohort was followed for 3 years for incident cardiovascular death and myocardial infarction.

RESULTS

In the derivation cohort, 10 of 101 patients with an hs-cTnI level below 2.5 pg/mL had inducible myocardial ischemia (NPV, 90% [95% CI, 83% to 95%]) and 3 of 101 had inducible ischemia involving at least 10% of the myocardium (NPV, 97% [CI, 92% to 99%]). In the validation cohort, 4 of 32 patients with an hs-cTnI level below 2.5 pg/mL had inducible ischemia (NPV, 88% [CI, 71% to 96%]) and 2 of 32 had ischemia of 10% or greater (NPV, 94% [CI, 79% to 99%]). After a median follow-up of 3 years in the derivation cohort, no adverse events occurred in patients with an hs-cTnI level below 2.5 pg/mL, compared with 33 (7%) cardiovascular deaths or incident myocardial infarctions among those with an hs-cTnI level of 2.5 pg/mL or greater.

LIMITATION

The data may not be applicable to a population without known CAD or to persons with unstable angina, and the modest sample sizes warrant further validation in a larger cohort.

CONCLUSION

Very low hs-cTnI levels may be useful in excluding inducible myocardial ischemia in patients with stable CAD.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Value of Prehospital Troponin Assessment in Suspected Non-ST-Elevation Acute Coronary Syndrome

There is an increasing awareness that prehospital risk stratification in patients with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS) is important. The HEART score accurately identifies patients at low risk and is nowadays fully assessable outside the hospital after the development of point-of-care (POC) troponin tests. However, the added value of the troponin component to the prehospital HEART score has not yet been assessed. This is a prospective cohort study including 700 patients with suspected NSTE-ACS in which prehospital risk stratification using the HEART score was performed by paramedics. Low risk was defined as HEAR or HEART score ≦3. Troponin was measured by a POC troponin T Test device (Roche Cobas h232). Troponin <40 ng/l scored 0 point, troponin ≥40 ng/l scored 2 points. Primary end point was major adverse cardiac events (MACE) within 45 days after inclusion. Mean HEAR score was 4.5 ± 1.6, mean HEART score was 4.7 ± 1.7. Using the HEAR score, a total of 183 patients (26%) were stratified as low risk, whereas using the HEART score, 172 patients (25%) were stratified as low risk (p = 0.001). In both low-risk groups, there were no deaths within 45 days. Using HEAR, MACE occurred in 13 patients (7%) in the low-risk group, whereas using HEART, MACE occurred in 5 patients in the low-risk group (3%, p <0.001). The use of HEART (Area under the curve 0.74) obtained a higher predictive value compared to HEAR (Area under the curve 0.65, p <0.001) for MACE. In conclusion, in patients with suspected NSTE-ACS, the prehospital troponin component of the HEART score has important added predictive value.

Right bundle branch block in patients with suspected myocardial infarction

Aims:

The new European Society of Cardiology guideline for ST-segment elevation myocardial infarction recommends that left and right bundle branch block should be considered equal for recommending urgent angiography in patients with suspected myocardial infarction. We aimed to evaluate this novel recommendation in two prospective studies of patients with suspected myocardial infarction.

Methods and results:

We included 4067 patients presenting to the emergency department with suspected myocardial infarction. All patients had an ECG recorded immediately upon admission. Patients were classified as having right bundle branch block (RBBB), left bundle branch block (LBBB), bifascicular block (BFB) or no bundle branch block. All patients were followed for up to two years to assess mortality. In the overall population 125 (3.1%) patients had RBBB, 281 (6.9%) LBBB and 60 (1.5%) BFB. The final diagnosis of myocardial infarction was adjudicated in 20.8% (RBBB), 28.5% (LBBB), 23.3% (BFB) and 21.6% (no complete block) of patients. The mortality rate after one year was 10.7% (RBBB), 7% (LBBB), 17.5% (BFB) and 3.2% (no complete block). The adjusted hazard ratios were 1.29 (95% confidence interval (CI) 0.71–2.34; P=0.40) for RBBB, 1.71 (95% CI 1.17–2.50; P=0.006) for LBBB and 2.27 (95% CI 1.28–4.05; P=0.005) for BFB.

Conclusion:

Our results support the new European Society of Cardiology ST-segment elevation myocardial infarction guideline describing RBBB as a high risk for mortality in patients with suspected myocardial infarction. However, the data challenge the concept of RBBB as a trigger of acute angiography because the likelihood of myocardial infarction in a chest pain unit setting is equally frequent in patients without bundle branch block.

Prognostic implications of detectable cardiac troponin I below the 99th percentile in patients admitted to an emergency department without acute coronary syndrome

Background:

Detectable troponin below the 99th percentile may reflect an underlying cardiac abnormality which might entail prognostic consequences. This study aimed to investigate the prognosis of patients admitted to an emergency department (ED) with detectable troponin below the 99th percentile reference limit who did not present with an acute coronary syndrome (ACS).

Methods:

We analysed the clinical data of all consecutive patients admitted to the ED during the years 2012 and 2013 in whom cardiac troponin was requested by the attending clinician (cTnI Ultra Siemens, Advia Centaur). Patients with troponin below the 99th percentile of the reference population (40 ng/L) and who did not have a diagnosis of ACS were selected, and their mortality was evaluated in a 2-year follow-up.

Results:

A total of 2501 patients had a troponin level below the reference limit, with 43.9% of those showing detectable levels (>6 ng/L and <40 ng/L). Patients with detectable levels were elderly and had a higher prevalence of cardiovascular history and more comorbidities. The total mortality in the 2-year follow-up was 12.4% in patients with detectable troponin and 4.5% in patients with undetectable troponin (p<0.001). In the Cox multivariate regression analysis, the detectable troponin was an independent marker of mortality at 2 years (HR 1.62, 95% CI 1.07–2.45, p=0.021).

Conclusions:

Detectable troponin I below the 99th percentile is associated with higher mortality risk at 2-year follow-up in patients admitted to the ED who did not present with ACS.

The feasibility of the 1-h high-sensitivity cardiac troponin T algorithm to rule-in and rule-out acute myocardial infarction in Thai emergency patients: an observational study

Background

The 3-h high-sensitivity cardiac troponin T (hs-cTnT) algorithm is the most commonly used scheme to diagnose acute myocardial infarction. The 1-h hs-cTnT algorithm has recently been approved by the European Society of Cardiology as an alternative algorithm for earlier diagnosis. If the hs-cTnT test cannot discriminate the diagnosis of the patient at 1 h, the patient is defined as observational group. Their test must be repeated at 3 h. A high prevalence of this group may indicate a low clinical utility of the 1-h hs-cTnT algorithm. This study was aimed to estimate the proportion of the observational group in Thai emergency department (ED) patients and also the time to rule-in/out between both the algorithms.

Methods

A historical control study was conducted in patients with chest pain for 1–12 h at the ED of Siriraj Hospital, Bangkok, Thailand. The study compared two groups: one prospective group of all patients evaluated with the 1-h hs-cTnT algorithm between June and September 2017 and one historical control group evaluated with the 3-h hs-cTnT algorithm between January and March 2017.

Results

A total of 130 patients were included (3-h hs-cTnT algorithm group n = 65 and 1-h hs-cTnT algorithm group n = 65). Twelve patients [18.5% (95% CI 10.0–30.1)] were categorized as observational group in the 1-h hs-cTnT algorithm group. The mean rule-in/out times in the 3-h hs-cTnT algorithm and 1-h hs-cTnT algorithm groups were 238 min (SD 63.3) and 134 min (SD 68.5), respectively (both p < 0.001). The time to disposition was also shortened in the 1-h hs-cTnT algorithm group (p <  0.001). Multivariable regression analysis performed to identify and adjust for confounders among patient characteristics revealed no significant confounders.

Conclusions

The use of the 1-h hs-cTnT algorithm in the ED resulted in an acceptable proportion in the observational group and a decreased time to rule-in/out compared with the 3-h hs-cTnT algorithm.

High-Sensitivity Cardiac Troponin I and Clinical Risk Scores in Patients With Suspected Acute Coronary Syndrome

BACKGROUND

High-sensitivity cardiac troponin assays can help to identify patients who are at low risk of myocardial infarction in the emergency department. We aimed to determine whether the addition of clinical risk scores would improve the safety of early rule-out pathways for myocardial infarction.

METHODS

In 1935 patients with suspected acute coronary syndrome, we evaluated the safety and efficacy of 2 rule-out pathways alone or in conjunction with low-risk TIMI (Thrombolysis In Myocardial Infarction) (0 or 1), GRACE (Global Registry of Acute Coronary Events) (≤108), EDACS (Emergency Department Assessment of Chest Pain Score) (<16), or HEART (History, ECG, Age, Risk factors, Troponin) (≤3) scores. The European Society of Cardiology 3-hour pathway uses a single diagnostic threshold (99th percentile), whereas the High-STEACS (High-Sensitivity Troponin in the Evaluation of Patients With Acute Coronary Syndrome) pathway applies different thresholds to rule out (<5 ng/L) and rule in (>99th percentile) myocardial infarction.

RESULTS

Myocardial infarction or cardiac death during the index presentation or at 30 days occurred in 14.3% of patients (276/1935). The European Society of Cardiology pathway ruled out 70%, with 27 missed events giving a negative predictive value of 97.9% (95% CI, 97.1-98.6). The addition of a HEART score ≤3 reduced the proportion ruled out by the European Society of Cardiology pathway to 25% but improved the negative predictive value to 99.7% (95% CI, 99.0-100; P<0.001). The High-STEACS pathway ruled out 65%, with 3 missed events for a negative predictive value of 99.7% (95% CI, 99.4-99.9). No risk score improved the negative predictive value of the High-STEACS pathways, but all reduced the proportion ruled out (24% to 47%; P<0.001 for all).

CONCLUSIONS

Clinical risk scores significantly improved the safety of the European Society of Cardiology 3-hour pathway, which relies on a single cardiac troponin threshold at the 99th percentile to rule in and rule out myocardial infarction. Where lower thresholds are used to rule out myocardial infarction, as applied in the High-STEACS pathway, risk scores halve the proportion of patients ruled out without improving safety.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01852123.

Clinical Validation of a Novel High-Sensitivity Cardiac Troponin I Assay for Early Diagnosis of Acute Myocardial Infarction

BACKGROUND

Clinical performance of the novel high-sensitivity cardiac troponin I (Siemens-hs-cTnI-Centaur) assay is unknown. We aimed to clinically validate the Siemens-hs-cTnI-Centaur assay and develop 0/1-h and 0/2-h algorithms.

METHODS

We enrolled patients presenting to the emergency department with symptoms suggestive of acute myocardial infarction (AMI). Final diagnoses were centrally adjudicated by 2 independent cardiologists including all clinical information twice: first, using serial hs-cTnT (Roche-Elecsys, primary analysis); second, using hs-cTnI (Abbott-Architect, secondary analysis) measurements in addition to the clinically applied (hs)-cTn. Siemens-hs-cTnI-Centaur was measured at presentation, 1 h, and 2 h. The primary objective was a direct comparison of diagnostic accuracy, quantified by the area under the ROC curve (AUC), of Siemens-hs-cTnI-Centaur vs the 2 established hs-cTn assays (Roche-hs-cTnT-Elecsys, Abbott-hs-cTnI-Architect). Secondary objectives included the development of Siemens-hs-cTnI-Centaur-specific 0/1-h and 0/2-h algorithms.

RESULTS

AMI was the final diagnosis in 318 of 1755 (18%) patients (using Roche-hs-cTnT-Elecsys for adjudication). The AUC at presentation for Siemens-hs-cTnI-Centaur was 0.94 (95% CI, 0.92–0.96) and comparable with 0.95 (95% CI, 0.93–0.97) for Roche-hs-cTnT-Elecsys and 0.93 (95% CI, 0.90–0.96) for Abbott-hs-cTnI-Architect. Applying the derived Siemens-hs-cTnI-Centaur 0/1-h algorithm to the validation cohort, 46% of patients were ruled out (sensitivity, 99.1%; 95% CI, 95.3–100), and 18% of patients were ruled in (specificity, 94.1%; 95% CI, 91.8–95.9). The Siemens-hs-cTnI-Centaur 0/2-h algorithm ruled out 55% of patients (sensitivity, 100%; 95% CI, 94.1–100), and ruled in 18% of patients (specificity, 96.0%; 95% CI, 93.1–97.9). Findings were confirmed in the secondary analyses using serial measurements of Abbott-hs-cTnI-Architect for adjudication.

CONCLUSIONS

Diagnostic accuracy and clinical utility of the novel Siemens-hs-cTnI-Centaur assay are high and comparable with the established hs-cTn assays. ClinicalTrials.gov Identifier: NCT00470587

Nuclear factor kappa B in patients with a history of unstable angina: case re-opened

This study aims at assessing NF-kB activity in unstable angina (UA) patients free of symptoms after a 1 year follow-up (1YFU). Plasma oxidized low-density lipoproteins (oxLDL), circulating NF-kB, Interleukin 6 (IL-6) and Interleukin 1β (IL-1β), high-sensitivity C-reactive protein (hs-CRP), as markers of oxidative stress and inflammation and plasma double-stranded DNA (ds-DNA), as marker of Neutrophil Extracellular Traps (NETs), were measured in 23 of the previously enrolled 27 UA patients. These measurements were compared to the UA data at baseline, and then compared to the data derived from the stable angina (SA) and controls (C) enrolled in our previous study (we demonstrated that UA had higher levels of NF-kB compared to SA and C). After a 1YFU, UA patients show a significant decrease in NF-kB, IL-6, hs-CRP, oxLDL, and ds-DNA plasma levels (p < 0.001) and in IL-1β and White Blood Cells (WBC) (p < 0.005), without differences in lipid and glucose assessment. If compared to SA and C, UA after a 1YFU have higher levels of NF-kB, IL-6, ds-DNA, WBC, and oxLDL compared to C (p < 0.001), but only IL-6 is higher than SA (p < 0.001). No differences are found in lipid and glucose assessment. After a 1YFU, patients with a history of UA improve their oxidative and inflammatory status, such as the levels of circulating ds-DNA, without achieving the status of C. They become comparable to SA subjects. This study provides new insight on the multiple and apparently contradictory facets of NF-kB in UA and on its possible role as mediator in NETs' formation.

Prevalence and outcome of patients referred for chest pain with high-sensitivity troponin elevation and no diagnosis at discharge

INTRODUCTION

Specialized chest pain units appear to increase the proportion of patients with acute chest pain who are properly evaluated, but some of them remain doubtful.

HYPOTHESIS

The aim of this study was to evaluate the survival and occurrence of cardiovascular events in patients without diagnosis at the end of management of chest pain with high-sensitivity troponin (Tn) elevation.

METHOD

All consecutive patients who came to the cardiac emergency room of Poitiers University Hospital between January 1, 2014, and August 7, 2015, for chest pain and Tn elevation were included. The primary endpoint was the number of undiagnosed patients; secondary endpoints included survival and major adverse cardiac events.

RESULTS

A total of 1001 patients (695 male; mean age, 68 ±16 years) who had chest pain and Tn elevation were included. Median follow-up was 24.5 (IQR, 14.7-29.5) months. Forty-seven (4.7%) patients remained without diagnosis. Compared with patients with diagnosis, these patients were younger (53.6 ±19.7 years; P < 0.0001) and had less hypertension (29.8%; P < 0.0001), diabetes (4.3%; P = 0.0016), and history of coronary artery disease (6.4%; P < 0.0001). No patients died or experienced MACE in 6-month follow-up. Survival curves showed the probability of survival was excellent, not only at 6 months, but also at 36 months (P = 0.0025).

CONCLUSIONS

Less than 5% of patients referred for chest pain and with high-sensitivity Tn elevation remained without diagnosis after adapted care in the chest pain unit. Their 6-month prognosis was excellent.

Clinical implications of high-sensitivity cardiac troponins

Cardiac troponin assays have become more sensitive over the years leading to the clinical introduction of high-sensitivity cardiac troponin assays in 2010. Their use has revolutionized the assessment of patients with chest pain in the emergency department by allowing earlier rule-in and rule-out of myocardial infarction leading to shorter stays in the emergency department and reduced admissions for chest pain. The incidence of myocardial infarction has increased slightly, and patients with myocardial infarction diagnosed with high-sensitivity cardiac troponins have been found to have a reduced risk of reinfarction, though without an impact on survival. High-sensitivity cardiac troponins are powerful predictors of long-term mortality and cardiovascular disease in the general population as well as in patients with chest pain with or without cardiovascular disease. The increase in risk for death and cardiovascular disease associated with high-sensitivity cardiac troponins is graded and starts already at detectable levels, well below the upper normal level. The aim of this review was to describe the clinical use and consequences of the introduction of high-sensitivity cardiac troponins. In addition, the importance of persistently elevated troponin levels for prognosis and what investigations may be appropriate to perform in patients with stable troponin elevations are discussed.

[Essential cardiac biomarkers in the differential diagnosis of acute chest pain : An update]

Cardiac biomarkers are an integral part of the diagnostic work-up and risk stratification of patients with chest pain. Cardiac troponins are highly sensitive diagnostic biomarkers in patients with acute coronary syndrome and have prognostic value in a multitude of acute and chronic diseases. In patients with suspected pulmonary embolism (PE) D‑dimer can be used together with the Wells score for exclusion of PE. In patients with confirmed PE, B‑type natriuretic peptide (BNP), N‑terminal pro-BNP (NT-proBNP) and heart-type fatty acid binding protein (h-FABP) can be used for risk stratification. Although normal D‑dimer levels largely decrease the possibility of acute aortic dissection, clinicians should not rely on D‑dimer alone to exclude the diagnosis of acute aortic syndrome. This continuing medical education article provides an overview of the most important biomarkers recommended in current guidelines for differential diagnoses of patients with chest pain with a focus on cardiac troponins in acute coronary syndrome.

High-sensitive cardiac troponin hs-TnT levels in sudden deaths related to atherosclerotic coronary artery disease

INTRODUCTION

Ischemic heart disease (IHD) related to atherosclerotic coronary artery disease (CAD) is one of the most prevalent causes of death in Europe. Postmortem evaluation of IHD remains a challenge because of possible non-specific autopsy finding in some autopsy cases, especially in early myocardial ischemia. High-sensitive cardiac troponin T (hs-TnT) is used today in clinical practice as the "gold standard" to diagnose the myocardial ischemia, and might also be applied as an ancillary tool for post-mortem evaluation.

PURPOSE

The goal of this study is to evaluate the diagnostic value of post-mortem serum hs-TnT assay in cases of sudden death related to IHD. We will also investigate the influence of cardiopulmonary resuscitation (CPR) attempts on post-mortem hs-TnT levels.

METHODS

The hs-TnT values in serum were retrospectively analysed in 85 autopsy data. 52 cases with clinical history and morphological results suggesting cardiac ischemia were included in the study group (mean age 53.5; age range 34-75) and 33 cases in the control group (mean age 40.4; age range 15-69). The group's statistical comparison was performed using logistic regression model.

RESULTS

Our study showed a significant non-linear association between hs-TnT serum values and post-mortem diagnosis of sudden deaths related to IHD (p-value 0.005). The shape of the relationship is showing that the probability of death due to IHD increases quickly with a light level of hs-TnT (maximum around 90ng/L) then decreases slightly while remaining at high in values. No significant difference in the hs-TnT serum values was found between the CPR and the non-CPR cases (p-value 0.304).

CONCLUSION

The measurement of hs-TnT serum values might be considered as an ancillary tool for the evaluation of death related to IHD, while taking necessary precautions in the interpretation of the results.

State-of-the-art diagnosis of myocardial infarction

The current version of the Universal Definition of Myocardial Infarction (MI) was published in 2012. An acute myocardial infarction (AMI) is characterized by evidence of myocardial necrosis in a clinical setting of acute myocardial ischemia. Diagnostic criteria include a rise and/or fall of serially tested cardiac biomarkers (preferentially cardiac troponins) with at least one value above the 99th percentile of the upper reference limit combined with symptoms of ischemia, new changes on electrocardiogram (ECG), imaging evidence of a new loss of viable myocardium or new regional wall motion abnormalities or the identification of an intracoronary thrombus by angiography or autopsy. Compared to previous versions, the current definition of MI includes minor modifications regarding ECG criteria and subtypes of MI as well as the use of cardiac imaging and high sensitivity troponin assays. This article summarizes the Universal MI definition and includes recommendations from the current guidelines for the management of patients with acute coronary syndrome. Strategies for "early rule-in" and "rule-out" of non-ST-elevation MI with high sensitivity cardiac troponin assays, risk scores for assessment of ischemic and bleeding risk and criteria for optimal timing of angiography are presented.

Determinants and prognosis of high-sensitivity cardiac troponin T peak plasma concentration in patients hospitalized for non-cardiogenic shock

Purpose:

The aim of this study was to assess the determinants and prognostic value of high-sensitivity cardiac troponin T peak plasma concentration in intensive care unit patients with non-cardiogenic shock.

Material and methods:

A prospective observational cohort study was conducted in a single intensive care unit between November 2014 and December 2015.

Results:

During the study period, 206 patients were hospitalized in the intensive care unit for non-cardiogenic shock and the median peak high-sensitivity cardiac troponin T was 55.1 [24.5–136] pg/mL. A multivariate analysis combining all variables showed that higher body mass index (t = 2.52, P = 0.01), lower left ventricular systolic function (t = −2.73, P = 0.007), higher white blood cell count (t = 3.72, P = 0.0001), lower creatinine clearance (t = −2.84, P = 0.0005), higher lactate level (t = 2.62, P = 0.01) and ST-segment depression (t = 3.98, P = 0.0001) best correlated with log₁₀-transformed high-sensitivity cardiac troponin T peak plasma concentration. After multivariate analysis, the high-sensitivity cardiac troponin T peak was not associated with a significant reduction of in-hospital mortality (adjusted odds ratio = 0.99 (95% confidence interval: 0.93–1.02)).

Conclusion:

High-sensitivity cardiac troponin T elevation was very common in patients hospitalized for non-cardiogenic shock. The factors significantly associated with high-sensitivity cardiac troponin T peak plasma concentration were higher body mass index, decreased left ventricular systolic ejection fraction, higher leucocyte count, decreased renal function, increased lactate level, and ST-segment depression. The high-sensitivity cardiac troponin T peak was not significantly associated with in-hospital mortality in this setting.

Evaluating Rapid Rule-out of Acute Myocardial Infarction Using a High-Sensitivity Cardiac Troponin I Assay at Presentation

BACKGROUND

Low concentrations of cardiac troponin (cTn) have been recommended for rapid rule-out of acute myocardial infarction (AMI). We examined the Beckman Coulter Access high-sensitivity cardiac troponin I (hs-cTnI) assay to identify a single test threshold that can safely rule out AMI.

METHODS

This analysis used stored samples collected in 2 prospective observational studies. In all, 1871 patients presenting to a tertiary emergency department with symptoms of acute coronary syndrome had blood taken for measurement of cTnI on presentation. The endpoint was type 1 myocardial infarction (T1MI). Sensitivity and negative predictive value (NPV) were calculated for hs-cTnI values below the 99th percentile.

RESULTS

Ninety-eight patients had T1MI (5.2%), and 638 (34.1%) patients had an hs-cTnI &lt;2 ng/L (limit of detection), with sensitivity of 99.0% (95% CI, 94.4%–100%) and NPV of 99.8% (95% CI, 99.1%–100%). No hs-cTnI value above a concentration of 2 ng/L achieved sensitivity of 99%. However, an NPV of 99.5% was achieved at values &lt;6 ng/L. A cutoff &lt;6 ng/L enabled 1475 (78.8%) patients to be ruled out on presentation with sensitivity of 93.9% (95% CI, 87.1%–97.7%).

CONCLUSIONS

A single baseline cTn &lt;2 ng/L measured with the Access hs-cTnI assay performed well for rule-out of AMI. This cutoff concentration identified 99% of patients with AMI and could reduce the number of patients requiring lengthy assessment. A cutoff of &lt;6 ng/L yielded a high NPV but missed more cases of AMI than would be acceptable to clinicians.

Nardilysin is a promising biomarker for the early diagnosis of acute coronary syndrome

BACKGROUND

Biomarkers for detection of transient myocardial ischemia in patients with unstable angina (UA) or for very early diagnosis of acute myocardial infarction (AMI) are not currently available.

METHODS AND RESULTS

We performed two sequential screenings of autoantibodies elevated shortly after the onset of acute coronary syndrome (ACS), and focused on metalloendopeptidase nardilysin (NRDC) among 19 identified candidate antigens. In a retrospective analysis among 93 ACS and 117 non-ACS patients, the serum level of NRDC was significantly increased in patients with ACS compared with that in patients with non-ACS (2073.5±189.8pg/ml versus 775.7±63.4pg/ml, P<0.0001). The area under the curve of NRDC for the diagnosis of ACS was 0.822 by the receiver operating characteristic curves analysis. In the time course analysis in 43 consecutive ACS patients (AMI: N=35 and UA: N=8), serum concentration of NRDC was significantly increased even in UA patients with a peak serum NRDC levels reached at admission both in AMI and UA patients. In a mouse model of AMI, we found an acute increase in serum NRDC and reduced NRDC expression in ischemic regions shortly after coronary artery ligation. NRDC expression was also reduced in infarcted regions in human autopsy samples from AMI patients. Moreover, the short treatment of primary culture of rat cardiomyocytes with H₂O₂ or A23187 induced NRDC secretion without cell toxicity.

CONCLUSION

NRDC is a promising biomarker for the early detection of ACS, even in UA patients without elevation of necrosis markers.

Effectiveness to identify acute myocardial infarction using the Manchester screening in patients with chest pain at the emergency service

BACKGROUND

Among cardiovascular diseases (CVD), acute coronary syndrome (ACS) is the main manifestation, corresponding to signs and symptoms that occur with ischemia and outcome of angina or acute myocardial infarction (AMI). The aim of this study was to investigate the performance of biochemical markers eligible in a chest pain protocol, using Point of care Test (POCT), in patients in a reference emergency room.

METHODS

In this study, 1380 medical records of patients of both genders were evaluated, ranked by applying chest pain protocol using the Manchester Triage System (MTS). Markers for myocardial injury were measured in serial analysis including myoglobin (Mgb), creatine kinase MB fraction mass (CK-MB), and cardiac troponin I (cTnI).

RESULTS

Acute myocardial infarction was predominant in males (P < .001), in patients with hypertension (P < .001), and in those with previous myocardial infarction (P < .026) and significant electrocardiogram (ECG) data for AMI screening (P < .001). A multivariate regression model showed as predictors for AMI the variables ECG data by admittance at the emergency room, previous AMI history, levels of both Mgb at the third hour, and cTnI at the sixth hour after admission.

CONCLUSION

This study showed the importance of a rapid and serial test as a cardiac marker for AMI screening, as well as has indicated the importance of time between the onset of chest pain and admission to the emergency room as an efficient aid in diagnosing this life-threatening disease.

Clinical Significance of Elevated High-sensitivity Troponin T in Low Likelihood Acute Coronary Syndrome Patients

High-sensitivity cardiac troponin T (hs-cTnT) is widely used in Oman and other Gulf countries. The availability of newer generation hs-cTnT has increased the sensitivity of diagnosing non-ST-elevation acute coronary syndrome (ACS). They utilize same antibodies as fourth-generation assay but can measure 10-fold lower levels of cTnT. Any detectable level above the 99^th percentile of population suggests myocardial damage. However, the cause could be non-ACS. Therefore, the increase in sensitivity of hs-cTnT assays for ACS comes at the cost of a reduced ACS specificity because more patients with other causes of myocardial injury are detected than with previous cTnT assays. Hence, there is large confusion among emergency physicians regarding optimal cutoff values to definitely confirm non-ST-elevation ACS, especially in patients with low likelihood of ACS. This review summarizes the available clinical and biochemical data to make recommendations about hs-cTnT cutoff values which will guide physicians to take decision in patients presenting with low likelihood ACS.

Clinical Laboratory Practice Recommendations for the Use of Cardiac Troponin in Acute Coronary Syndrome: Expert Opinion from the Academy of the American Association for Clinical Chemistry and the Task Force on Clinical Applications of Cardiac Bio-Markers of the International Federation of Clinical Chemistry and Laboratory Medicine

This document is an essential companion to the third iteration of the National Academy of Clinical Biochemistry [NACB,8 now the American Association for Clinical Chemistry (AACC) Academy] Laboratory Medicine Practice Guidelines (LMPG) on cardiac markers. The expert consensus recommendations were drafted in collaboration with the International Federation of Clinical Chemistry and Laboratory Medicine Task Force on Clinical Applications of Bio-Markers (IFCC TF-CB). We determined that there is sufficient clinical guidance on the use of cardiac troponin (cTn) testing from clinical practice groups. Thus, in this expert consensus document, we focused on clinical laboratory practice recommendations for high-sensitivity (hs)-cTn assays. This document utilized the expert opinion class of evidence to focus on the following 10 topics: (a) quality control (QC) utilization, (b) validation of the lower reportable analytical limits, (c) units to be used in reporting measurable concentrations for patients and QC materials, (d) 99th percentile sex-specific upper reference limits to define the reference interval; (e) criteria required to define hs-cTn assays, (f) communication with clinicians and the laboratory's role in educating clinicians regarding the influence of preanalytic and analytic problems that can confound assay results, (g) studies on hs-cTn assays and how authors need to document preanalytical and analytical variables, (h) harmonizing and standardizing assay results and the role of commutable materials, (i) time to reporting of results from sample receipt and sample collection, and (j) changes in hs-cTn concentrations over time and the role of both analytical and biological variabilities in interpreting results of serial blood collections.

Effect of Acute Coronary Syndrome Probability on Diagnostic and Prognostic Performance of High-Sensitivity Cardiac Troponin

BACKGROUND

There is concern that high-sensitivity cardiac troponin (hs-cTn) may have low diagnostic accuracy in patients with low acute coronary syndrome (ACS) probability.

METHODS

We prospectively stratified patients presenting with acute chest discomfort to the emergency department (ED) into 3 groups according to their probability for ACS as assessed by the treating ED physician using a visual analog scale: ≤10%, 11% to 79%, and ≥80%, reviewing all information available at 90 min. hs-cTnT and hs-cTnI concentrations were determined in a blinded fashion. Two independent cardiologists adjudicated the final diagnosis.

RESULTS

Among 3828 patients eligible for analysis, 1189 patients had low (≤10%) probability for ACS. The incidence of non-ST-segment elevation myocardial infarction (NSTEMI) increased from 1.3% to 12.2% and 54.8% in patients with low, intermediate, and high ACS probability, respectively. The positive predictive value of hs-cTnT and hs-cTnI was low in patients with low ACS probability and increased with the incidence of NSTEMI, whereas the diagnostic accuracy of hs-cTnT and hs-cTnI for NSTEMI as quantified by the area under the curve (AUC) was very high and comparable among all 3 strata, e.g., AUC hs-cTnI, 0.96 (95% CI, 0.94–0.97); 0.87 (95% CI, 0.85–0.89); and 0.89 (95% CI, 0.87–0.92), respectively. Findings were validated using bootstrap analysis as an alternative methodology to define ACS probability. Similarly, higher hs-cTnT/I concentrations independently predicted all-cause mortality within 2 years (e.g., hs-cTnT hazard ratio, 1.39; 95% CI, 1.27–1.52), irrespective of ACS probability.

CONCLUSIONS

Diagnostic and prognostic accuracy and utility of hs-cTnT and hs-cTnI remain high in patients with acute chest discomfort and low ACS probability.

ClinicalTrials.gov Identifier: NCT00470587.

A direct comparison of decision rules for early discharge of suspected acute coronary syndromes in the era of high sensitivity troponin

BACKGROUND

We tested the hypothesis that a single high sensitivity troponin at limits of detection (LOD HSTnT) (<5 ng/l) combined with a presentation non-ischaemic electrocardiogram is superior to low-risk Global Registry of Acute Coronary Events (GRACE) (<75), Thrombolysis in Myocardial Infarction (TIMI) (≤1) and History, ECG, Age, Risk factors and Troponin (HEART) score (≤3) as an aid to early, safe discharge for suspected acute coronary syndrome.

METHODS

In a prospective cohort study, risk scores were computed in consecutive patients with suspected acute coronary syndrome presenting to the Emergency Room of a large English hospital. Adjudication of myocardial infarction, as per third universal definition, involved a two-physician, blinded, independent review of all biomarker positive chest pain re-presentations to any national hospital. The primary and secondary outcome was a composite of type 1 myocardial infarction, unplanned coronary revascularisation and all cause death (MACE) at six weeks and one year.

RESULTS

Of 3054 consecutive presentations with chest pain 1642 had suspected acute coronary syndrome (52% male, median age 59 years, 14% diabetic, 20% previous myocardial infarction). Median time from chest pain to presentation was 9.7 h. Re-presentations occurred in eight hospitals with 100% follow-up achieved. Two hundred and eleven (12.9%) and 279 (17%) were adjudicated to suffer MACE at six weeks and one year respectively. Only HEART ≤3 (negative predictive value MACE 99.4%, sensitivity 97.6%, %discharge 53.4) and LOD HSTnT strategy (negative predictive value MACE 99.8%, sensitivity 99.5%, %discharge 36.9) achieved pre-specified negative predictive value of >99% for MACE at six weeks. For type 1 myocardial infarction alone the negative predictive values at six weeks and one year were identical, for both HEART ≤3 and LOD HSTnT at 99.8% and 99.5% respectively.

CONCLUSION

HEART ≤3 or LOD HSTnT strategy rules out short and medium term myocardial infarction with ≥99.5% certainty, and short-term MACE with >99% certainty, allowing for early discharge of 53.4% and 36.9% respectively of suspected acute coronary syndrome. Adoption of either strategy has the potential to greatly reduce Emergency Room pressures and minimise follow-up investigations. Very early presenters (<3 h), due to limited numbers, are excluded from these conclusions.

Multi-centre evaluation of recent troponin assays for the diagnosis of NSTEMI

Objectives

We aimed to compare the use of nine different cardiac troponin (cTn) assays (2 cTnT and 7 cTnI) for the diagnosis of NSTEMI in a single multi-centre population.

Design and methods

One hundred and fifty-eight patients were included (mean age 60 years, SD 17 years), including 23 patients (14%) with NSTEMI.

Results

The analytical comparison highlighted a large heterogeneity of cTn assays, as reflected by percentages of patients with detectable cTn, correlation coefficients, Passing-Bablok comparisons and concordance coefficients. Correlations within cTnI assays were good and correlation within cTnT assays was excellent. Diagnostic performances demonstrated that each cTn assay has specific threshold values. Furthermore, some assays (HS-cTnI and T, cTnI-Pathfast and cTnI-Centaur) indicated high sensitivity and negative predictive value using the limit of detection (LoD) diagnostic strategy. For the latter assays, a significant increase in specificity was found when using the 99th percentile or the H0-H3 strategies, in comparison to the LoD strategy. When applying the European Society of Cardiology H0-H3 algorithm, comparable diagnostic performances were obtained.

Conclusion

All 9 cTn assays indicated overall good diagnostic performances for the diagnosis of NSTEMI in emergency departments when the recommended algorithm based on the variation of cTn value between two measurements at admission and 3 h later was used.

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We compare nine troponin assays for the diagnosis of NSTEMI.

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Each cTn assay owns specific thresholds for the ESC H0-H3 algorithm.

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All assays present high specificity for NSTEMI diagnosis using H0-H3 algorithm.

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Assay-specific threshold and delta change values for each cTn assays are mandatory.