Outcomes in Patients With Chest Pain Discharged After Evaluation Using a High-Sensitivity Troponin T Assay

Prognosis is worse with elevated cardiac troponin in nonacute coronary syndrome compared with acute coronary syndrome

BACKGROUND

Cardiac troponin (cTn) can be elevated in many patients presenting to the emergency department (ED) with chest pain but without a diagnosis of acute coronary syndrome (ACS). We compared the prognostic significance of cTn in these different populations.

METHODS

We retrospectively analyzed the CHOPIN study, which enrolled patients who presented to the ED with chest pain. Patients were grouped as ACS, non-ACS cardiovascular disease, noncardiac chest pain and chest pain not otherwise specified (NOS). We examined the prognostic ability of cTnI for the clinical endpoints of mortality and major adverse cardiovascular event (MACE; a composite of acute myocardial infarction, unstable angina, revascularization, reinfarction, and congestive heart failure and stroke) at 180-day follow-up.

RESULTS

Among 1982 patients analyzed, 14% had ACS, 21% had non-ACS cardiovascular disease, 31% had a noncardiac diagnosis and 34% had chest pain NOS. cTnI elevation above the 99th percentile was observed in 52, 18, 6 and 7% in these groups, respectively. cTnI elevation was associated with mortality and MACE, and their relationships were more prominent in noncardiac diagnosis and chest pain NOS than in ACS and non-ACS cardiovascular diagnoses for mortality, and in non-ACS patients than in ACS patients for MACE (hazard ratio for doubling of cTnI 1.85, 2.05, 8.26 and 4.14, respectively; P for interaction 0.011 for mortality; 1.04, 1.23, 1.54 and 1.42, respectively; P for interaction <0.001 for MACE).

CONCLUSION

In patients presenting to the ED with chest pain, cTnI elevation was associated with a worse prognosis in non-ACS patients than in ACS patients.

Performance of the European Society of Cardiology 0/1-Hour, 0/2-Hour, and 0/3-Hour Algorithms for Rapid Triage of Acute Myocardial Infarction : An International Collaborative Meta-analysis

BACKGROUND

The 2020 European Society of Cardiology (ESC) guidelines recommend using the 0/1-hour and 0/2-hour algorithms over the 0/3-hour algorithm as the first and second choices of high-sensitivity cardiac troponin (hs-cTn)-based strategies for triage of patients with suspected acute myocardial infarction (AMI).

PURPOSE

To evaluate the diagnostic accuracies of the ESC 0/1-hour, 0/2-hour, and 0/3-hour algorithms.

DATA SOURCES

PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus from 1 January 2011 to 31 December 2020. (PROSPERO: CRD42020216479).

STUDY SELECTION

Prospective studies that evaluated the ESC 0/1-hour, 0/2-hour, or 0/3-hour algorithms in adult patients presenting with suspected AMI.

DATA EXTRACTION

The primary outcome was index AMI. Twenty unique cohorts were identified. Primary data were obtained from investigators of 16 cohorts and aggregate data were extracted from 4 cohorts. Two independent authors assessed each study for methodological quality.

DATA SYNTHESIS

A total of 32 studies (20 cohorts) with 30 066 patients were analyzed. The 0/1-hour algorithm had a pooled sensitivity of 99.1% (95% CI, 98.5% to 99.5%) and negative predictive value (NPV) of 99.8% (CI, 99.6% to 99.9%) for ruling out AMI. The 0/2-hour algorithm had a pooled sensitivity of 98.6% (CI, 97.2% to 99.3%) and NPV of 99.6% (CI, 99.4% to 99.8%). The 0/3-hour algorithm had a pooled sensitivity of 93.7% (CI, 87.4% to 97.0%) and NPV of 98.7% (CI, 97.7% to 99.3%). Sensitivity of the 0/3-hour algorithm was attenuated in studies that did not use clinical criteria (GRACE score <140 and pain-free) compared with studies that used clinical criteria (90.2% [CI, 82.9 to 94.6] vs. 98.4% [CI, 88.6 to 99.8]). All 3 algorithms had similar specificities and positive predictive values for ruling in AMI, but heterogeneity across studies was substantial. Diagnostic performance was similar across the hs-cTnT (Elecsys; Roche), hs-cTnI (Architect; Abbott), and hs-cTnI (Centaur/Atellica; Siemens) assays.

LIMITATION

Diagnostic accuracy, inclusion and exclusion criteria, and cardiac troponin sampling time varied among studies.

CONCLUSION

The ESC 0/1-hour and 0/2-hour algorithms have higher sensitivities and NPVs than the 0/3-hour algorithm for index AMI.

PRIMARY FUNDING SOURCE

National Taiwan University Hospital.

Potential impact of a novel pathway for suspected myocardial infarction utilising a new high-sensitivity cardiac troponin I assay

BACKGROUND

High-sensitivity cardiac troponin I (hs-cTnI) assays promise high diagnostic accuracy for myocardial infarction (MI). In an ED where conventional cTnI was in use, we evaluated an assessment pathway using the new Access hsTnI assay.

METHODS

This retrospective analysis recruited ED patients with suspected MI between June and September 2019. All patients received routine care with a conventional cTnI assay (AccuTnI +3: limit of detection (LoD) 10 ng/L, 99th centile upper reference limit (URL) 40 ng/L, abnormal elevation cut-point 80 ng/L). Arrival, then 90-minute or 360-minute cTnI levels for low and non-low risk patients, respectively (ED Assessment of Chest pain score) guided diagnosis and disposition which was at treating physician discretion. The same patients had arrival and 90-minute or 180-minute samples drawn for hs-cTnI levels (Access hsTnI: LoD 2 ng/L, 99th centile URL 10 ng/L (females) and 20 ng/L (males); abnormal elevation above the URL and delta >30%). Treating physicians were blinded to the hs-cTnI results. Using the hs-cTnI values, investigators retrospectively assigned likely diagnosis, disposition and likelihood of a 30-day major adverse cardiac event (MACE). Admission was recommended for significantly rising hs-cTnI elevations. The primary objective was to demonstrate an acceptable unexpected 30-day post-discharge MACE rate of <1%. cTnI elevation rates, diagnostic outcomes and ED disposition were also compared between pathways.

RESULTS

For the 935 patients, unexpected 30-day post-discharge MACE rates were 0/935 (0%, 95% CI 0% to 0.4%) with the conventional or novel pathway. For the high-sensitivity and conventional assays, respectively, abnormal elevation rates were 29% (95% CI 26% to 32%) and 19% (95% CI 17% to 22%), for MI were 9% (95% CI 8% to 11%) and 8% (95% CI 6% to 10%), and for hospital admission were 42% (95% CI 39% to 45%) and 43% (95% CI 40% to 47%).

CONCLUSION

The novel pathway using the Access hsTnI assay has an acceptably low 30-day MACE rate.

Cardiac troponin I and the risk of cardiovascular or non-cardiovascular death in patients visiting the emergency department

The prognostic implication of cardiac troponin I (cTnI) values for the determination of the magnitude or duration of cause-specific death risk is limited. We included consecutive patients with maximal cTnI values within 24 h of their emergency department visits. Multivariate analyses using variables selected by the Bayesian information criterion were performed to investigate the impact of cTnI on the event rate, time-dependent risk, and dose-dependent risk of cardiovascular or non-cardiovascular death within 360 days. There were 5472 (14.9%) all-cause deaths including 881 (2.4%) cardiovascular deaths and 4591 (12.5%) non-cardiovascular deaths. In patients with positive cTnI, defined as the ≥ 99th percentile of the upper normal limit, the cumulative risk of cardiac and non-cardiac death was 4.4- and 1.4-fold higher, respectively, than that of negative cTnI, respectively. In the competing risk analysis, positive cTnI was linked to 2.4- and 1.2-fold higher risks of cardiovascular and non-cardiovascular death, respectively. The cTnI value showed a positive relationship with the risk of both cardiovascular and non-cardiovascular deaths. In the time-dependent risk analysis, the excess risk of cardiovascular death was mostly evident in the first few weeks. Higher cTnI value was associated with an increased risk of both cardiovascular and non-cardiovascular death, especially which was in the early period.

High-sensitivity troponin assays for early rule-out of acute myocardial infarction in people with acute chest pain: a systematic review and economic evaluation

BACKGROUND

Early diagnosis of acute myocardial infarction is important, but only 20% of emergency admissions for chest pain will actually have an acute myocardial infarction. High-sensitivity cardiac troponin assays may allow rapid rule out of myocardial infarction and avoid unnecessary hospital admissions.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of high-sensitivity cardiac troponin assays for the management of adults presenting with acute chest pain, in particular for the early rule-out of acute myocardial infarction.

METHODS

Sixteen databases were searched up to September 2019. Review methods followed published guidelines. Studies were assessed for quality using appropriate risk-of-bias tools. The bivariate model was used to estimate summary sensitivity and specificity for meta-analyses involving four or more studies; otherwise, random-effects logistic regression was used. The health economic analysis considered the long-term costs and quality-adjusted life-years associated with different troponin testing methods. The de novo model consisted of a decision tree and a state-transition cohort model. A lifetime time horizon (of 60 years) was used.

RESULTS

Thirty-seven studies (123 publications) were included in the review. The high-sensitivity cardiac troponin test strategies evaluated are defined by the combination of four factors (i.e. assay, number and timing of tests, and threshold concentration), resulting in a large number of possible combinations. Clinical opinion indicated a minimum clinically acceptable sensitivity of 97%. When considering single test strategies, only those using a threshold at or near to the limit of detection for the assay, in a sample taken at presentation, met the minimum clinically acceptable sensitivity criterion. The majority of the multiple test strategies that met this criterion comprised an initial rule-out step, based on high-sensitivity cardiac troponin levels in a sample taken on presentation and a minimum symptom duration, and a second stage for patients not meeting the initial rule-out criteria, based on presentation levels of high-sensitivity cardiac troponin and absolute change after 1, 2 or 3 hours. Two large cluster randomised controlled trials found that implementation of an early rule-out pathway for myocardial infarction reduced length of stay and rate of hospital admission without increasing cardiac events. In the base-case analysis, standard troponin testing was both the most effective and the most costly. Other testing strategies with a sensitivity of 100% (subject to uncertainty) were almost equally effective, resulting in the same life-year and quality-adjusted life-year gain at up to four decimal places. Comparisons based on the next best alternative showed that for willingness-to-pay values below £8455 per quality-adjusted life-year, the Access High Sensitivity Troponin I (Beckman Coulter, Brea, CA, USA) [(symptoms > 3 hours AND < 4 ng/l at 0 hours) OR (< 5 ng/l AND Δ < 5 ng/l at 0 to 2 hours)] would be cost-effective. For thresholds between £8455 and £20,190 per quality-adjusted life-year, the Elecsys® Troponin-T high sensitive (Roche, Basel, Switzerland) (< 12 ng/l at 0 hours AND Δ < 3 ng/l at 0 to 1 hours) would be cost-effective. For a threshold > £20,190 per quality-adjusted life-year, the Dimension Vista® High-Sensitivity Troponin I (Siemens Healthcare, Erlangen, Germany) (< 5 ng/l at 0 hours AND Δ < 2 ng/l at 0 to 1 hours) would be cost-effective.

CONCLUSIONS

High-sensitivity cardiac troponin testing may be cost-effective compared with standard troponin testing.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019154716.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 25, No. 33. See the NIHR Journals Library website for further project information.

Cardiac troponin I predicts clinical outcome of patients with cancer at emergency department

BACKGROUND

The prognostic ability of cardiac troponin I (TnI) has been demonstrated in general populations and among cardiovascular disease patients, but it has not been evaluated in cancer patients.

HYPOTHESIS

This study assumes to have the prognostic ability of cardiac troponin in cancer patients visiting the emergency department.

METHODS

Cancer patients visiting the emergency department were enrolled in this retrospective cohort study. Patients with previously known coronary artery disease or clinically indicated coronary angiography were not included. The maximal value from Siemens ADVIA Centaur troponin I Ultra assay within 24 hours was assessed. The primary endpoint was 180-day all-cause death, including cardiovascular and noncardiovascular death.

RESULTS

A total of 9135 cancer patients (mean age: 63 years, male gender: 60%) were enrolled. Lowest (0.006 ng/mL), assay-specific <99th % (0.007-0.039 ng/mL), below median ≥ 99th % (0.040-0.129 ng/mL), and above median ≥ 99th % (≥0.130 ng/mL) TnI were found in 4487 (49.1%), 3158 (34.6%), 852 (9.3%), and 638 (7.0%) patients, respectively. There was 3192 (34.9%) all-cause deaths including 137 (1.5%) cardiovascular and 3047 (33.4%) noncardiovascular deaths in the 180-day follow-up period. The risks of all-cause, cardiovascular, and noncardiovascular death increased across higher TnI strata (hazard ratio [HR] = 1.3-2.9; 2.1-9.3; 1.3-1.8; P < .001, all). These findings were consistent within clinical subgroups including solid and hematologic cancers.

CONCLUSIONS

Cancer patients visiting the emergency department with elevated troponin I were at increased risk of 180-day death. Cancer patients with elevated TnI may need additional evaluation or careful follow-up even without cardiovascular disease diagnosis.

Is rheumatoid arthritis a risk factor for acute coronary syndrome also among individuals at elevated risk, such as individuals presenting with acute chest pain?

Background

Patients with rheumatoid arthritis (RA) are, on average, at increased risk of acute coronary syndrome (ACS) compared to the general population, but it remains unknown whether RA remains an ACS risk factor also in settings where the ACS risk is already high elevated, such as among individuals presenting to the emergency department (ED) with chest pain.

Methods and results

We included 49 283 individuals (514 (1.0%) had RA) presenting with chest pain at the four hospital EDs in Stockholm, Sweden, 2013–2016 in a cohort study. Information on exposure (RA), outcome (ACS) and comorbidities was provided through national registers. The association between RA and ACS was assessed, overall and by levels of high-sensitivity cardiac troponin T (hs-cTnT) and number of ACS risk factors, using logistic regression models adjusted for age, sex, hospital, calendar year and cardiovascular risk factors. ACS was more common in patients with (8.2%) than without (4.6%) RA, adjusted OR =1.4, 95% CI 1.0 to 2.0. This association was particularly strong in individuals with initial hs-cTnT levels between 5 and 14 ng/L, or no additional ACS risk factors (adjusted ORs above 2), but no longer detectable in those with hs-cTnT >14 ng/L or with three or more additional ACS risk factors.

Conclusion

RA is a risk factor for ACS also among patients at the ED with chest pain. This association is not explained by traditional ACS risk factors, and most pronounced in patients with normal hs-cTnT and few other ACS risk factors, prompting particular ACS vigilance in this RA patient group.

Family history of coronary artery disease is associated with acute coronary syndrome in 28,188 chest pain patients

Background:

The value of family history of coronary artery disease (CAD) in diagnosing acute coronary syndrome (ACS) in chest pain patients is uncertain, especially in relation to high-sensitivity assays for cardiac troponin T (hs-cTnT), which have improved ACS diagnostics. Our objective was to investigate the association between verified family history of CAD and ACS in chest pain patients, overall and in different strata of initial hs-cTnT.

Methods:

Data on chest pain patients visiting four emergency departments in Sweden during 2013–2016 were cross-referenced with national registers of kinship, diseases and prescriptions. Family history of early CAD was defined as the occurrence of myocardial infarction or coronary revascularization before the age of 55 years in male and 65 years in female first-degree relatives. The outcome was combined including ACS and cardiovascular death within 30 days of presentation.

Results:

Of 28,188 patients, 4.7% of patients had ACS. In total, 8.2% and 32.4% had a family history of early and ever-occurring CAD, respectively. Family history of CAD was positively associated with the outcome, independently of age, gender, cardiovascular risk factors and electrocardiogram findings. The strongest association was observed for family history of early CAD (odds ratio 1.62, 95% confidence interval 1.35–1.94). Stronger associations were observed in young patients (e.g. &lt;65 years) and in patients with non-elevated initial hs-cTnT levels (p-value for interaction = 0.004 and 0.001, respectively).

Conclusions:

Family history of CAD is associated with ACS in chest pain patients, especially in patients of young age or with non-elevated initial hs-cTnT levels.

Fifth generation troponin T assay is subject to antibody interference

BACKGROUND

The fifth generation (high-sensitivity) troponin T assay offers increased precision and analytical sensitivity to the predecessor method. The assay has proven utility in risk stratification and patient management. Upon clinical suspicion and discordant 4th generation troponin T and troponin I results, we investigated a sample for suspected interfering substances to the 5th generation troponin T assay.

METHODS

The analysis included a serial dilution, treatment with polyethylene glycol, commercial antibody blocking reagents, and size exclusion chromatography.

RESULTS

The sample diluted linearly (R² = 0.9957); however, experienced a dramatic reduction in concentration after both the polyethylene glycol and blocking agent treatment. Finally, size exclusion chromatography demonstrated assay reactivity around 970 kDa range.

CONCLUSIONS

These experiments elucidate a heterophilic antibody interference to the assay, and demonstrate potential measures to discern the interference.

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.

Defining and managing patients with non-ST-elevation myocardial infarction: Sorting through type 1 vs other types

Advances in cardiovascular (CV) imaging, redefined electrocardiogram criteria, and high‐sensitivity CV biomarker assays have enabled more differentiated etiological classification of myocardial infarction (MI). Type 1 MI has a different underlying pathophysiology than type 2 through type 5 MI; type 1 MI is characterized primarily by intracoronary atherothrombosis and the other types by a variety of mechanisms, which can occur with or without an atherosclerotic component. In type 2 MI, there is evidence of myocardial oxygen supply‐demand imbalance unrelated to acute coronary atherothrombosis. Types 1 and 2 MI are spontaneous events, while type 4 and type 5 are procedure‐related; type 3 MI is identified only after death. Most type 1 and type 2 MI present as non‐ST‐elevation MI (NSTEMI), although both types can also present as ST‐elevation MI. Because of their different underlying etiologies, type 1 and type 2 NSTEMI have different presentation and prognosis and should be managed differently. In this article, we discuss the epidemiology, prognosis, and management of NSTEMI occurring in the setting of underlying type 1 or type 2 pathophysiology. Most NSTEMI (65%–90%) are type 1 MI. Patients with type 2 MI have multiple comorbidities and causes of in‐hospital mortality among these patients are not always CV‐related. It is important to distinguish between type 1 and type 2 NSTEMI early in the clinical course to allow for the use of the most appropriate treatments that will provide the greatest benefit for these patients.

High-Sensitivity Troponin I in Hospitalized and Ambulatory Patients With Heart Failure With Preserved Ejection Fraction: Insights From the Heart Failure Clinical Research Network

Background We sought to study the prevalence of high-sensitivity troponin and its association with cardiac structure and outcomes in ambulatory and hospitalized patients with heart failure with a preserved ejection fraction ( HF p EF ). Methods and Results A post hoc analysis utilized data from HF p EF patients: DOSE (Diuretic Optimization Strategies Evaluation) and CARRESS - HF (Cardiorenal Rescue Study in Acute Decompensated Heart Failure) enrolled patients hospitalized with acute HF p EF , and RELAX (Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in Heart Failure With Preserved Ejection Fraction) enrolled ambulatory patients with HF p EF . High-sensitivity troponin I (hs-TnI) was measured in hospitalized patients at baseline, at 72 to 96 hours, on day 7, and on day 60. In ambulatory patients hs-TnI was measured at baseline and at week 24. In the ambulatory cohort, correlations between hs-TnI and cardiac structure and function were assessed. The association between hs-TnI and a 60-day composite of emergency room visits, readmissions, and death was assessed for hospitalized patients using multivariable Cox proportional hazard models. The study population included 139 hospitalized and 212 ambulatory patients with HF p EF and hs-TnI measured at baseline. The median (25th, 75th percentiles) baseline troponin was 17.6 (11.1, 41.0) ng/L in hospitalized patients and 9.5 (5.3, 19.7) ng/L in ambulatory patients ( P<0.001). The prevalence of elevated hs-TnI (>99% percentile upper reference limit was 86% in hospitalized patients and 53% among ambulatory patients, with stable elevation in ambulatory patients during follow-up. HF p EF patients with a hs-TnI above the median were older with worse left ventricular hypertrophy and diastolic dysfunction. Continuously valued hs-TnI (per doubling) was associated with increased risk of composite end point (adjusted hazard ratio 1.20, 95% confidence interval 1.00-1.43; P=0.042). Conclusions Hs-TnI is commonly elevated among both hospitalized and ambulatory patients with HF p EF . Increased hs-TnI levels are associated with worse cardiac structure and increased risk of adverse events.

The role of coronary CT angiography for acute chest pain in the era of high-sensitivity troponins

Accurate and efficient diagnostic triage for acute chest pain (ACP) remains one of the most challenging problems in the emergency department (ED). While the proportion of patients that present with myocardial infarction (MI), aortic dissection, or pulmonary embolism is relatively low, a missed diagnosis can be life threatening. Coronary computed tomography angiography (CCTA) has developed into a robust diagnostic tool in the triage of ACP over the past decade, with several trials showing that it can reliably identify patients at low risk of major adverse cardiovascular events, shorten the length of stay in the ED, and reduce cost associated with the triage of patients with undifferentiated chest pain. Recently, however, high-sensitivity troponin assays have been increasingly incorporated as a rapid and efficient diagnostic test in the triage of ACP due to their higher sensitivity and negative predictive value of myocardial infarction. As more EDs adopt high-sensitivity troponin assays into routine clinical practice, the role of CCTA will likely change. In this review, we provide an overview of CCTA and high-sensitivity troponins for evaluation of patients with suspected ACS in the ED. Moreover, we discuss the changing role of CCTA in the era of high-sensitivity troponins.

[Biomarkers in the diagnosis of cardiovascular emergencies : Acute coronary syndrome and differential diagnoses]

In emergency situations, patients present with symptoms rather than diagnoses. Due to its high prevalence, the acute coronary syndrome (ACS) dominates acute diagnostics as a consequence of its chief complaint chest pain. The challenge for the attending physicians is that only a minor part of patients with chest pain are finally diagnosed with an acute myocardial infarction (AMI) and that other rare but dangerous differential diagnoses have to be kept in mind and-vice versa-severely ill patients with AMI may present with symptoms other than chest pain. Against this background, the initial evaluation of patients requires a process-orientated view beyond the key roles of clinical assessment and biomarkers. The use of cardiac troponin is mandatory for the diagnosis of ACS, but challenging in broader utilization due to the reduced clinical specificity. Further relevant biomarkers are copeptin in combination with cardiac troponin or natriuetic peptides, which help to diagnose relevant cardiac dysfunction in (acute) heart failure. In addition, patients who present with the symptom of a suspected cardiac syncope need the differential diagnosis of an underlying arrhythmia, which may be due to an ACS or reduced left ventricular (LV) function and other causes like pulmonary embolism or structural heart disease (e. g. aortic valve stenosis). This highlights that biomarker-based diagnostics are often crucial to decide after the initial clinical evaluation whether early imaging is needed or early discharge is possible.

High-sensitivity troponin T and long-term adverse cardiac events among patients presenting with suspected acute coronary syndrome in Singapore

INTRODUCTION

Prognostic thresholds for 30-day major adverse cardiac events (MACE) have been studied for high-sensitivity troponin T (hsTnT) in patients with suspected acute coronary syndrome (ACS), but there is limited data on the prognostic performance of hsTnT for one-year MACE.

METHODS

We prospectively measured hsTnT (in ng/mL up to two decimal places) at 0, 2 and 7 hours for patients presenting with symptoms suggestive of ACS to our emergency department from March 2010 to April 2013. We assessed the prognostic performance of hsTnT cut-offs for 30-day and one-year MACE, and the utility of delta-hsTnT in predicting MACE.

RESULTS

Among 2,444 patients studied, 273 (11.2%) developed MACE (including index MACE) by 30 days and 359 (14.7%) patients developed MACE at one year. The suggested hsTnT cut-off for 30-day MACE was ≥ 10 ng/L at 0 hour (positive predictive value [PPV] 33.5%, negative predictive value [NPV] 94.5%) and 7 hours (PPV 37.3%, NPV 94.5%), and ≥ 20 ng/L at 2 hours (PPV 36.9%, NPV 96.9%). For one-year MACE, the suggested cut-off was also ≥ 10 ng/L at all readings. Plasma hsTnT ≥ 30 ng/L at any reading gave PPV > 54% and NPV > 93% for 30-day MACE. Absolute 0-2 hour and 2-7 hour delta-hsTnT ≥ 10 ng/L gave PPV > 50% for 30-day and one-year MACE.

CONCLUSION

Patients with 0-, 2- or 7-hour hsTnT ≥ 30 ng/L and 0-2 hour delta-hsTnT ≥ 10 ng/L had PPV > 50% for 30-day and one-year MACE, and should be investigated thoroughly.

A Rule-Out Strategy Based on High-Sensitivity Troponin and HEART Score Reduces Hospital Admissions

STUDY OBJECTIVE

We evaluate whether a combination of a 1-hour high-sensitivity cardiac troponin algorithm and History, ECG, Age, Risk Factors, and Troponin (HEART) score reduces admission rate (primary outcome) and affects time to discharge, health care-related costs, and 30-day outcome (secondary outcomes) in patients with symptoms suggestive of an acute coronary syndrome.

METHODS

This prospective observational multicenter study was conducted before (2013 to 2014) and after (2015 to 2016) implementation of a strategy including level of high-sensitivity cardiac troponin T or I at 0 and 1 hour, combined with the HEART score. Patients with a nonelevated baseline high-sensitivity cardiac troponin level, a 1-hour change in high-sensitivity cardiac troponin T level less than 3 ng/L, or high-sensitivity cardiac troponin I level less than 6 ng/L and a HEART score less than or equal to 3 were considered to be ruled out of having acute coronary syndrome. A logistic regression analysis was performed to adjust for differences in baseline characteristics.

RESULTS

A total of 1,233 patients were included at 6 centers. There were no differences in regard to median age (64 versus 63 years) and proportion of men (57% versus 54%) between the periods. After introduction of the new strategy, the admission rate decreased from 59% to 33% (risk ratio 0.55 [95% confidence interval {CI} 0.48 to 0.63]; odds ratio 0.33 [95% CI 0.26 to 0.42]; adjusted odds ratio 0.33 [95% CI 0.25 to 0.42]). The median hospital stay was reduced from 23.2 to 4.7 hours (95% CI of difference -20.4 to -11.4); median health care-related costs, from $1,748 to $1,079 (95% CI of difference -$953 to -$391). The number of clinical events was very low.

CONCLUSION

In this before-after study, clinical implementation of a 1-hour high-sensitivity cardiac troponin algorithm combined with the HEART score was associated with a reduction in admission rate and health care burden, with very low rates of adverse clinical events.

Identifying Myocardial Ischemia due to Coronary Microvascular Dysfunction in the Emergency Department: Introducing a New Paradigm in Acute Chest Pain Evaluation

Chest pain stands as one of the most frequent patient presentations in the emergency department (ED). Despite established diagnostic algorithms for identifying several important causes of chest pain, such as acute myocardial infarction (AMI), aortic dissection, and pulmonary embolism, guidance on managing patients with recurrent chest pain, one of the top 3 reasons for repeated hospitalization in the United States, is less defined. The assessment of symptoms, serial ECG, and necrosis biomarkers plays a major role in patient management. Notably, the recently introduced high-sensitivity troponin T (hs-TnT) assay is helping to identify ischemia in patients previously undiagnosed by conventional testing. In Europe, with the use of this assay for over a decade, the identification of patients with AMI has substantially increased, particularly of patients with type 2 AMI, which is seen in the absence of atherosclerotic obstruction of the epicardial coronaries on angiography. Use of hs-TnT is in particular relevant in women, in whom the use of a sex-specific threshold for elevated hs-TnT has almost doubled the diagnosis of AMI. With the advent of the hs-TnT assay in the United States in 2017, a similar phenomenon is expected. Thus, it is important to learn from the European experience and to develop sex-specific nuanced algorithms for the evaluation of additional causes of myocardial ischemia/necrosis, such as coronary artery vasomotor disorders and coronary microvascular dysfunction. The latter has a high prevalence among symptomatic women presenting to the ED, a group in whom recurrent chest pain is common. This commentary describes the tools available for diagnosing epicardial- and non-epicardial-related myocardial ischemia in patients with recurrent chest pain in the ED setting. A sex-specific, nuanced approach applied to select groups of patients being observed in the ED has the potential to reduce admissions and to allow for the initiation of timely, appropriate medical treatment and outpatient follow-up in an at-risk population. The costs and availability of advanced diagnostics may pose some limitation to the widespread adoption of such protocols.

High-sensitivity troponin in the evaluation of patients with suspected acute coronary syndrome: a stepped-wedge, cluster-randomised controlled trial

BACKGROUND

High-sensitivity cardiac troponin assays permit use of lower thresholds for the diagnosis of myocardial infarction, but whether this improves clinical outcomes is unknown. We aimed to determine whether the introduction of a high-sensitivity cardiac troponin I (hs-cTnI) assay with a sex-specific 99th centile diagnostic threshold would reduce subsequent myocardial infarction or cardiovascular death in patients with suspected acute coronary syndrome.

METHODS

In this stepped-wedge, cluster-randomised controlled trial across ten secondary or tertiary care hospitals in Scotland, we evaluated the implementation of an hs-cTnI assay in consecutive patients who had been admitted to the hospitals' emergency departments with suspected acute coronary syndrome. Patients were eligible for inclusion if they presented with suspected acute coronary syndrome and had paired cardiac troponin measurements from the standard care and trial assays. During a validation phase of 6-12 months, results from the hs-cTnI assay were concealed from the attending clinician, and a contemporary cardiac troponin I (cTnI) assay was used to guide care. Hospitals were randomly allocated to early (n=5 hospitals) or late (n=5 hospitals) implementation, in which the high-sensitivity assay and sex-specific 99th centile diagnostic threshold was introduced immediately after the 6-month validation phase or was deferred for a further 6 months. Patients reclassified by the high-sensitivity assay were defined as those with an increased hs-cTnI concentration in whom cTnI concentrations were below the diagnostic threshold on the contemporary assay. The primary outcome was subsequent myocardial infarction or death from cardiovascular causes at 1 year after initial presentation. Outcomes were compared in patients reclassified by the high-sensitivity assay before and after its implementation by use of an adjusted generalised linear mixed model. This trial is registered with ClinicalTrials.gov, number NCT01852123.

FINDINGS

Between June 10, 2013, and March 3, 2016, we enrolled 48 282 consecutive patients (61 [SD 17] years, 47% women) of whom 10 360 (21%) patients had cTnI concentrations greater than those of the 99th centile of the normal range of values, who were identified by the contemporary assay or the high-sensitivity assay. The high-sensitivity assay reclassified 1771 (17%) of 10 360 patients with myocardial injury or infarction who were not identified by the contemporary assay. In those reclassified, subsequent myocardial infarction or cardiovascular death within 1 year occurred in 105 (15%) of 720 patients in the validation phase and 131 (12%) of 1051 patients in the implementation phase (adjusted odds ratio for implementation vs validation phase 1·10, 95% CI 0·75 to 1·61; p=0·620).

INTERPRETATION

Use of a high-sensitivity assay prompted reclassification of 1771 (17%) of 10 360 patients with myocardial injury or infarction, but was not associated with a lower subsequent incidence of myocardial infarction or cardiovascular death at 1 year. Our findings question whether the diagnostic threshold for myocardial infarction should be based on the 99th centile derived from a normal reference population.

FUNDING

The British Heart Foundation.

Clinical features and prognosis of patients with acute non-specific chest pain in emergency and cardiology departments after the introduction of high-sensitivity troponins: a prospective cohort study

OBJECTIVES

To determine the incidence of clinical, cardiac-related endpoints and mortality among patients presenting to an emergency or cardiology department with non-specific chest pain (NSCP), and who receive testing with a high-sensitivity troponin. A second objective was to identify risk factors for the above-noted endpoints during 12 months of follow-up.

DESIGN

A prospective multicentre study.

SETTING

Emergency and cardiology departments in Southern Denmark.

SUBJECTS

The study enrolled 1027 patients who were assessed for acute chest pain in an emergency or cardiology department, and in whom a myocardial infarction or another obvious reason for chest pain had been ruled out. Patients were enrolled from September 2014 to June 2015 and followed for 1 year.

MAIN OUTCOME MEASURES

Clinical, cardiac-related endpoints (cardiac-related death, acute myocardial infarction, unstable angina and coronary revascularisation) and all-cause mortality.

RESULTS

Over a period of 1 year, cardiac-related endpoints were found in 19 patients (1.9%): 0 patients experienced cardiac-related death, 2 (0.2%) had myocardial infarction, 4 (0.4%) had unstable angina pectoris and 17 (1.7%) underwent coronary revascularisation. All-cause mortality was observed in seven patients (0.7%). When compared with the general population, the standardised mortality ratio did not differ. The risk factors associated with the study endpoints included male gender, body mass index >25 kg/m², previous known coronary artery disease, hypertension, hypercholesterolaemia, diabetes mellitus and the use of statins. A total of 73% of the endpoints occurred in males.

CONCLUSION

The prognosis for patients with NSCP is favourable, with a 1-year mortality after discharge that is comparable with the background population. Few clinical endpoints took place during follow-up, and those that did were predominantly in males.