Comparative Evaluation of 2-Hour Rapid Diagnostic Algorithms for Acute Myocardial Infarction Using High-Sensitivity Cardiac Troponin T

Whole Blood Cardiac Troponin "Triaging" to Improve Early Detection of Myocardial Injury at a Pediatric Hospital

BACKGROUND

The importance of offering on-site cardiac troponin (cTn) testing at pediatric hospitals may be underappreciated. We developed a rapid rule-in process for myocardial injury at a pediatric hospital experiencing delays in off-site high-sensitivity cardiac troponin T (hs-cTnT) testing.

METHODS

Collect-to-verify turnaround times (TATs) for off-site testing were reviewed. Pre-analytic changes to improve TATs were devised, implemented and evaluated, after which a new analyzer was selected and evaluated for on-site cTn testing. Performance of the new analyzer's assay was compared to the off-site hs-cTnT assay, and post go-live TATs for on-site testing were assessed.

RESULTS

Median collect-to-verify TAT for short turnaround-time (STAT) priority off-site plasma hs-cTnT testing was 104 min, with 35% of orders having a TAT >120 min. Eliminating serum separator tubes and requiring a separate plasma separator tube did not significantly reduce TATs. A QuidelOrtho Triage® MeterPro whole blood cardiac troponin I (cTnI) assay was implemented to "triage" time-critical and STAT priority specimens collected for off-site hs-cTnT testing. Elevated cTnI (≥0.02 µg/L) had a sensitivity of 91% for clear elevations in hs-cTnT (≥53 ng/L) but a 0% sensitivity for modest elevations (5 to 13 ng/L, 14 to 52 ng/L). An interpretive comment was auto-appended to cTnI results indicating that clinicians should wait for the hs-cTnT result if cTnI was normal. Median collect-to-verify TAT for on-site cTnI testing was <50% the TAT for off-site hs-cTnT testing.

CONCLUSIONS

On-site point-of-care whole blood cTn testing can rapidly confirm significant or late-presenting myocardial injury. Combined with simultaneous off-site high-sensitivity cardiac troponin (hs-cTn) testing, this workflow is a viable interim solution for pediatric hospitals without on-site hs-cTn testing.

Performance of the 0/2-hour high-sensitivity cardiac troponin T diagnostic protocol in a multisite United States cohort

BACKGROUND

The diagnostic performance of the high-sensitivity troponin T (hs-cTnT) 0/2-h algorithm is unclear among U.S. emergency department (ED) patients with acute chest pain.

METHODS

A preplanned subgroup analysis of the STOP-CP cohort study was conducted. Participants with 0- and 2-h hs-cTnT measures prospectively enrolled at eight U.S. EDs from January 2017 to September 2018 were stratified into rule-out, observation, and rule-in zones using the hs-cTnT 0/2-h algorithm alone and combined with the history, electrocardiogram, age, and risk factor (HEAR) score. The primary outcome was adjudicated 30-day cardiac death or myocardial infarction (CDMI). The sensitivity and negative predictive value (NPV) of the 0/2-h rule-out zone and specificity and positive predictive value (PPV) of the rule-in zone for 30-day CDMI were calculated.

RESULTS

Of the 1307 patients accrued, 53.6% (700/1307) were male and 58.6% (762/1307) were White, with a mean ± SD age of 57.5 ± 12.7 years. At 30 days, CDMI occurred in 12.9% (168/1307) of participants. The 0/2-h algorithm ruled out 61.4% (802/1307) of patients. Among rule-out patients, 1.9% (15/802) experienced 30-day CDMI, resulting in a sensitivity of 91.1% (95% confidence interval [CI] 85.7%-94.9%) and NPV of 98.1% (95% CI 96.9%-98.9%). The 0/2-h algorithm ruled in 12.4% (162/1307) patients of whom 61.7% (100/162) experienced 30-day CDMI. The rule-in zone specificity was 94.6% (95% CI 93.1%-95.8%) and PPV was 61.7% (95% CI 53.8%-69.2%) for 30-day CDMI. The 0/2-h algorithm combined with HEAR score ruled out 30.7% (401/1307) of patients with a sensitivity and NPV for 30-day CDMI of 98.2% (95% CI 94.9%-99.6%) and 99.3% (95% CI 97.8%-99.8%), respectively.

CONCLUSIONS

The hs-cTnT 0/2-h algorithm ruled out most patients. With NPV of <99% for 30-day CDMI, the hs-cTnT 0/2-h algorithm, many emergency physicians may not consider it safe to use for U.S. ED patients. When combined with a low-risk HEAR score, NPV was >99% for 30-day CDMI at the cost of reduced efficacy.

Impact of a high sensitivity troponin accelerated diagnostic protocol on the safety and emergency department length of stay of chest pain in an academic tertiary hospital: a quality improvement study

PURPOSE

High-sensitivity troponin (hsTn) accelerated diagnostic protocols are highly recommended for evaluating acute coronary syndromes. Our goal was to improve care for chest pain patients through the safe adoption of an accelerated diagnostic protocol in our academic Emergency Department (ED) with an aim to reduce mean ED length of stay for chest pain patients by 1 h over 1.5 years. Pre-accelerated diagnostic protocol, our mean ED length of stay for chest pain patients was 9.0 h.

METHODS

Using the Model for Improvement, we implemented a two-hour accelerated diagnostic protocol and conducted two Plan-Do-Study-Act cycles and education efforts to improve accelerated diagnostic protocol compliance and decrease ED length of stay. Using control charts, we measured the mean monthly ED length of stay for chest pain patients to look for special cause evidence of improvement. Process measures measured compliance with the accelerated diagnostic protocol. Balancing measures included the ED length of stay for abdominal pain patients and the number of admissions and deaths at 7 days for chest pain patients.

RESULTS

Mean ED length of stay for chest pain patients decreased from 9.0 to 8.2 h post-accelerated diagnostic protocol. The mean time between troponins decreased from 3.9 to 3.0 h, and the percentage of second troponins repeated at < 2.75 h increased from 22.3% to 58.6%. For abdominal pain patients, ED length of stay decreased from 10.8 to 10.5 h. No chest pain patients died within 7 days pre- or post-accelerated diagnostic protocol. Pre-accelerated diagnostic protocol, 0.84% (41/4,905) were admitted within 7 days. Post-accelerated diagnostic protocol and accelerated diagnostic protocol compliant, 0.70% (13/1,844) were admitted. Post-accelerated diagnostic protocol and accelerated diagnostic protocol non-compliant, 1.1% (13/1,183) were admitted.

CONCLUSION

We safely introduced a hsTn accelerated diagnostic protocol in an academic ED. ED length of stay decreased for chest pain patients but did not meet our 1-h goal.

Serial high-sensitivity cardiac troponin testing for the diagnosis of myocardial infarction: a scoping review

OBJECTIVES

We aimed to assess the diversity and practices of existing studies on several assays and algorithms for serial measurements of high-sensitivity cardiac troponin (hs-cTn) for risk stratification and the diagnosis of myocardial infarction (MI) and 30-day outcomes in patients suspected of having non-ST-segment elevation MI (NSTEMI).

METHODS

We searched multiple databases including MEDLINE, EMBASE, Science Citation Index, the Cochrane Database of Systematic Reviews and the CENTRAL databases for studies published between January 2006 and November 2021. Studies that assessed the diagnostic accuracy of serial hs-cTn testing in patients suspected of having NSTEMI in the emergency department (ED) were eligible. Data were analysed using the scoping review method.

RESULTS

We included 86 publications, mainly from research centres in Europe, North America and Australasia. Two hs-cTn assays, manufactured by Abbott (43/86) and Roche (53/86), dominated the evaluations. The studies most commonly measured the concentrations of hs-cTn at two time points, at presentation and a few hours thereafter, to assess the two-strata or three-strata algorithm for diagnosing or ruling out MI. Although data from 83 studies (97%) were prospectively collected, 0%-90% of the eligible patients were excluded from the analysis due to missing blood samples or the lack of a final diagnosis in 53 studies (62%) that reported relevant data. Only 19 studies (22%) reported on head-to-head comparisons of alternative assays.

CONCLUSION

Evidence on the accuracy of serial hs-cTn testing was largely derived from selected research institutions and relied on two specific assays. The proportions of the eligible patients excluded from the study raise concerns about directly applying the study findings to clinical practice in frontline EDs.

PROSPERO REGISTRATION NUMBER

CRD42018106379.

Prospective comparative evaluation of the European Society of Cardiology (ESC) 1-hour and a 2-hour rapid diagnostic algorithm for myocardial infarction using high-sensitivity troponin-T

OBJECTIVE

Both 1- and 2-hour rapid diagnostic algorithms using high-sensitivity troponin (hs-cTn) have been validated to diagnose acute myocardial infarction (MI), leaving physicians uncertain which algorithm is preferable. The objective of this study was to prospectively evaluate the diagnostic performance of 1- and 2-hour algorithms in clinical practice in a Canadian emergency department (ED).

METHODS

ED patients with chest pain had high-sensitivity cardiac troponin-T (hs-cTnT) collected on presentation and 1- and 2-hours later at a single academic centre over a 2-year period. The primary outcome was index MI, and the secondary outcome was 30-day major adverse cardiac events (MACE). All outcomes were adjudicated.

RESULTS

We enrolled 608 patients undergoing serial hs-cTnT sampling. Of these, 350 had a valid 1-hour and 550 had a 2-hour hs-cTnT sample. Index MI and 30-day MACE prevalence was ~12% and 14%. Sensitivity of the 1- and 2-hour algorithms was similar for index MI 97.3% (95% CI: 85.8-99.9%) and 100% (95% CI: 91.6-100%) and 30-day MACE: 80.9% (95% CI: 66.7-90.9%) and 83.3% (95% CI: 73.2-90.8%), respectively. Both algorithms accurately identified about 10% of patients as high risk.

CONCLUSIONS

Both algorithms were able to classify almost two-thirds of patients as low risk, effectively ruling out MI and conferring a low risk of 30-day MACE for this group, while reliably identifying high-risk patients. While both algorithms had equivalent diagnostic performance, the 2-hour algorithm offers several practical advantages, which may make it preferable to implement. Broad implementation of similar algorithms across Canada can expedite patient disposition and lead to resource savings.

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.

Prevalence of Detectable Biotin in Five US Emergency Department Patient Cohorts

BACKGROUND

The objective of this study was to estimate the prevalence of biotin supplementation in United States emergency department patients using a multi-site, geographically distributed sampling model.

METHODS

Biotin was measured using an Abbott ARCHITECT Biotin research use only assay in 7118 emergency department patient serum or plasma samples from five US medical centers. Samples with biotin ≥10 ng/mL underwent additional LC-MS/MS confirmatory testing for biotin and its primary metabolites. The overall and site-specific prevalence of detectable biotin was determined using the screening assay while biotin speciation (i.e., prevalence of detectable metabolites) was determined using LC-MS/MS.

RESULTS

Of 7118 samples screened, 291 (4.1%) had biotin ≥10 ng/mL and were considered positive. Across five medical centers, the fraction of positive samples ranged from 2.0% to 5.4%. The maximum biotin concentration observed was 355 ng/mL. Of the 285 positive screens that underwent additional LC-MS/MS testing, 89 (31%) showed detectable biotin, bisnorbiotin, and/or biotin sulfoxide. Biotin, bisnorbiotin, and biotinsulfoxide were detected in 82/89 (92.1%), 61/89 (68.5%), and 18/89 (20.2%) samples, respectively; biotin was detected in the absence of either metabolite in 18/89 (20.2%) samples.

CONCLUSIONS

Using a screening assay, 4.1% of emergency department patient samples were found to be potentially susceptible to interference from biotin. Confirmatory testing showed detectable biotin and/or biotin metabolites in 31% of positive screens (1.3% overall). The prevalence of biotin ≥10 ng/mL varied 2-3-fold across US emergency department patient cohorts. Biotin metabolites were observed in 80% of samples confirmed to have detectable biotin species by LC-MS/MS, suggesting that rigorous assessments of assay susceptibility to biotin interference, often performed using in vitro studies, should consider the potential role of biotin metabolites present in vivo.

Cardiac troponin and defining myocardial infarction

The 4th Universal Definition of Myocardial Infarction has stimulated considerable debate since its publication in 2018. The intention was to define the types of myocardial injury through the lens of their underpinning pathophysiology. In this review, we discuss how the 4th Universal Definition of Myocardial Infarction defines infarction and injury and the necessary pragmatic adjustments that appear in clinical guidelines to maximize triage of real-world patients.

High-sensitivity methods for cardiac troponins: The mission is not over yet

The measurement of cardiac troponin (cTn) is recommended by all guidelines as the gold standard for the differential diagnosis of Acute Coronary Syndromes. The aim of this review is to discuss in details some key issues regarding both analytical and clinical characteristics of the high-sensitivity methods for cTn (hs-cTn), which are still considered controversial or unresolved. In particular, the major clinical concern regarding hs-cTn methods is the difficulty to differentiate the pathophysiological mechanism responsible for biomarker release from cardiomyocytes after reversible or irreversible injury, respectively. Indeed, recent experimental and clinical studies have demonstrated that different circulating forms of cTnI and cTnT can be respectively measured in plasma samples of patients with reversible or irreversible myocardial injury. Accordingly, a new generation of hs-Tn methods should be set up, based on immunometric immunoassays or chromatographic techniques, specific for circulating peptide forms more characteristics for reversible or irreversible myocardial injury. It is conceivable that this new generation of hs-cTn methods will complete the mission regarding the laboratory tests for specific cardiac biomarkers, started more than 20 years ago, which has already revolutionized the diagnosis, prognosis and management of patients with cardiac diseases.

Diastolic Function and Biomarkers of Long-Distance Walking Participants

BACKGROUND

The effects of long-distance walking on the cardiovascular system have been little studied.

OBJECTIVES

The general objective of this study was to verify these effects on the behavior of diastolic function and the cardiac biomarkers CK-MB (mass), troponin T, and NT-proBNP, in amateur athletes.

METHOD

This longitudinal study, conducted in 2015, evaluated participants during the following 5 stages: E0 (baseline) before starting the trajectory and the others, E1, E2, E3, and E4, at the end of each day, totaling 244.7 km. At all stages, the biomarkers NT-proBNP, CK-MB (mass), and troponin T were measured. Echocardiogram was performed to analyze the E, A and E' waves. P < 0.05 was adopted as significant.

RESULTS

The study evaluated 25 participants, with an average age of 46 ± 10.5 years and body mass index of 20.2 ± 2.3 kg/m2. Increased values were found for NT-proBNP from E0 to E1, E2, E3, and E4 (p < 0.001), CK-MB (mass) from E0 to E2 (p < 0.001), and E' wave from E0 to E1, E2, E3, and E4 (p < 0.001). Positive correlations were identified between the following: CK-MB (mass) and troponin T (E1: r = 0.524, p = 0.010; E4: r = 0.413, p = 0.044); CK-MB (mass) and NT-proBNP (E4: r = 0.539, p = 0.006); and E/A and E' (E0: r = 0.603, p < 0.001; E1: r = 0.639, p < 0.001; E4: r = 0.593, p = 0.002). A negative correlation was found between CK-MB (mass) and E/A (E1: r = -0.428, p = 0.041).

CONCLUSION

The effects of intense, prolonged, and interspersed physical activity were verified based on significant variations in the behavior of CK-MB (mass), NT-proBNP, and the E' wave. Notwithstanding the alterations found, there were no criteria suggestive of myocardial damage.

Comparative evaluation of 15-minute rapid diagnosis of ischemic heart disease by high-sensitivity quantification of cardiac biomarkers

A rapid clinical diagnosis may efficiently improve the survival rate and prognosis of patients with ischemic heart disease (IHD). Therefore, a one-step, rapid and inexpensive analysis for the quick diagnosis of IHD was investigated in the present study. Consecutive patients who were subjected to myoglobin, cardiac troponin I and creatine kinase-MB isoenzyme assessment at the Emergency Department of Shenzhen Second People's Hospital (Shenzhen, China) between December 2017 and March 2018 prior to treatment were screened. Clinically applicable disposable strips were employed for quantification of the cardiac biomarkers. The analytical performance of the strips was evaluated by receiver operating characteristic (ROC) curves and compared with the traditional chemiluminescence immunoassay (CLIA) method. The data of 391 participants were collected. At the baseline, 57 patients were diagnosed with IHD and 334 patients were diagnosed with other diseases. The area under the ROC curve (AUC) of the CLIA model was 0.787 (95% CI, 0.709-0.865) with a specificity of 76.7% and a sensitivity of 71.9%. At the optimal cutoff value of -1.867, the negative and the positive predictive value were 94.1 and 34.5%, respectively. The AUC of the disposable strip model was 0.792 (95% CI, 0.729-0.855). At the cutoff value of -1.820 or below, the negative predictive value was 94.9%, the positive predictive value was 28.9%, the specificity was 66.8% and the sensitivity was 79.0%. The P-value of the ROCs was 0.858, indicating no statistically significant difference between the two assay methods. The cost of the disposable strip was 50% of that of the CLIA method and it took only 25% of the time that was required for the quantification of the three cardiac markers by CLIA. In conclusion, the disposable strip provides a platform for point-of-care testing and may be an easy, rapid, reliable and cost-saving method for the diagnosis of IHD.

High-Sensitivity Cardiac Troponin I vs a Clinical Chemistry Score for Predicting All-Cause Mortality in an Emergency Department Population

BACKGROUND

For patients investigated for suspected acute coronary syndrome, there is uncertainty if a single measurement of high-sensitivity cardiac troponin I (hs-cTnI) at emergency department (ED) presentation can identify patients at both low and high risk for mortality.

METHODS

We included consecutive adult patients in the ED who had a Clinical Chemistry Score (CCS) taken at presentation (ie, combination of glucose, creatinine for estimated glomerular filtration rate determination, and hs-cTnI assay) in a Canadian city between 2012 and 2013. Outcomes were 3-month, 1-year, and 5-year all-cause mortality using the provincial death registry. Mortality rates and test performance (eg, sensitivity and specificity) with 95% confidence intervals (CIs) were obtained for the CCS or hs-cTnI assay alone using established cutoffs for these tests.

RESULTS

Our cohort included 5974 patients with a 1-year mortality rate of 17.2% (95% CI, 16.2-18.3). A CCS ≥ 1 yielded a sensitivity of 99.2% (95% CI, 98.4-99.6) compared with the hs-cTnI ≥ 5 ng/L cutoff sensitivity of 88.4% (95% CI, 86.3-90.3), with the mortality rate being significantly lower for patients with CCS < 1 (2.0%; 95% CI, 0.9-4.0) vs patients with hs-cTnI < 5 ng/L (5.0%; 95% CI, 4.2-6.0) at 1 year (P = 0.01). A CCS of 5 also yielded a higher specificity (88.5%; 95% CI, 87.5-89.3) compared with hs-cTnI > 26 ng/L (83.9%; 95% CI, 82.9-84.9), with no difference in mortality rates (37.4% vs 36.3%; P = 0.66). This trend was consistent at 3-month and 5-year mortality.

CONCLUSION

For patients in the ED with a potential cardiac issue, using the CCS cutoffs can better identify patients at low and high risk for mortality than using published cutoffs for hs-cTnI alone.

Rapid rule out for suspected myocardial infarction: is the algorithm appropriate for all?

Aims

Patients presenting to the emergency department (ED) with cardiac chest pain and high-sensitive troponin I (HsTnI) less than 5 ng/L have very good prognosis and low risk for major adverse cardiovascular events. The 2015 European Society of Cardiology (ESC) guidelines for non-ST-elevation myocardial infarction (MI)/acute coronary syndrome (ACS) suggests that patients with normal high-sensitive troponin, which are free of chest pain and have a global registry of acute coronary events (GRACE) score less than 140 are eligible for discharge from the hospital for outpatient workup. Our hypothesis suggests that not all patients with GRACE score under 140 should be discharged for ambulatory tests even with undetectable HsTnI as recommended in the guidelines.

Methods and results

Population-based retrospective cohort study in a large tertiary care centre. The study population included all patients discharged from the hospital between 1 February 2016 and 28 February 2019 following rule out of MI. During the study period, a total of 13 800 patients were discharged from the hospital after rule out of MI. Among them, 9236 (67%) had HsTnI below 5 ng/L. A total of 7705 patients (83%) met the criteria for low (n = 7162) or moderate (n = 543) GRACE risk score. Moderate-risk patients had significantly more adverse events than low-risk patients (4.6% vs. 2.1%, P &lt; 0.001). They are in higher risk of death (0.5% vs. 0.1%, P = 0.042), revascularization (3.9% vs. 1.8%, P = 0.0047), and readmission due to ACS (1.1% vs. 0.4%, P = 0.031).

Conclusion

Patients presenting to the ED with chest pain and HsTnI less than 5 ng/L and GRACE score under 140 have 2–4% adverse event in 60 days. The differences between the groups suggest using rapid rule out algorithms for only low-risk patients with GRACE score under 73.

High-sensitivity-cardiac troponin for accelerated diagnosis of acute myocardial infarction: A systematic review and meta-analysis

OBJECTIVES

Cardiovascular disease is the leading cause of mortality and morbidity. Serial troponin tests have been endorsed as essential diagnostic steps to rule out/-in acute myocardial infarction (AMI), and hs-cTn assays have shown promise in enhancing the accuracy and efficiency of AMI diagnosis in the emergency department (ED).

METHODS

A systematic review and meta-analysis of diagnostic test accuracy studies were conducted to compare the diagnostic performance of various accelerated diagnostic algorithms of hs-cTn assays for patients with symptoms of AMI. Random-effects bivariate meta-analysis was conducted to estimate the summary sensitivity, specificity, likelihood ratios, and area under receiver operating characteristic curve.

RESULTS

In the systematic review consisting of 56 studies and 67,945 patients, both hs-cTnT and hs-cTnI-based 0-, 1-, 2- and 0-1 h algorithms showed a pooled sensitivity >90%. The hs-cTnI-based algorithm showed a pooled specificity >80%. The hs-cTnT-based algorithms had a specificity of 68% for the 0-h algorithm and of around 80% for the 1-, 2-, and 0-1 h algorithms. The heterogeneities of all diagnostic algorithms were mild (I² < 50%).

CONCLUSION

Both hs-cTnI- and hs-cTnT-based accelerated diagnostic algorithms have high sensitivities but moderate specificities for early diagnosis of AMI. Overall, hs-cTnI-based algorithms have slightly higher specificities in early diagnosis of AMI. For patients presenting ED with typical symptoms, the use of hs-cTnT or hs-cTnI assays at the 99th percentile may help identify patients with low risk for AMI and promote early discharge from the ED.

A Multicenter Assessment of the Sensitivity and Specificity for a Single High-Sensitivity Cardiac Troponin Test at Emergency Department Presentation for Hospital Admission

Background

Studies have illustrated how a low or undetectable high-sensitivity cardiac troponin (hs-cTn) concentration at emergency department (ED) presentation can rule out myocardial infarction (MI). A problem with using an undetectable hs-cTn cutoff is that this value may be defined differently among hospitals and is also difficult to monitor. In the present study, we assess the diagnostic performance of a clinical chemistry score (CCS) vs hs-cTn alone in the presentation blood sample in the ED for patient hospital admission in a multicenter setting.

Methods

From January 1 to June 30, 2018, consecutive patients with random glucose, creatinine (for an estimated glomerular filtration rate calculation), and hs-cTnI (Abbott, 2 hospitals, Hamilton, Ontario, n = 10496) or hs-cTnT (Roche, 4 hospitals, Calgary, Alberta, n = 25177) were assessed for hospital admission with the CCS (range of scores, 0–5) or hs-cTn alone. Sensitivity, specificity, predicative values, and likelihood ratios were calculated for a CCS of 0 and 5 and for hs-cTn alone (hs-cTnI cutoffs, 5 and 26 ng/L; hs-cTnT cutoffs, 6 and 14 ng/L).

Results

The CCS of 0 (CCS &lt;1) identified approximately 10% of all patients as low risk and had a sensitivity for hospital admission of nearly 98% as compared to &lt;93% when hs-cTnT (&lt;6 ng/L) or hs-cTnI (&lt;5 ng/L) cutoffs alone were used. A CCS ≥5 had a specificity for hospital admission &gt;95%, with approximately 14% of patients at high risk.

Conclusions

An ED disposition (admit or send home) using the presentation blood sample could occur in nearly 25% of all patients by use of the CCS.

Role of High-sensitivity Cardiac Troponin in Acute Coronary Syndrome

Chest pain is one of the most common reasons for an emergency room (ER) visit in the US, with almost 6 million ER visits annually. High-sensitivity cardiac troponin (hscTn) assays have the ability to rapidly rule in or rule out acute coronary syndrome with improved sensitivity, and they are increasingly being used. Though hscTn assays have been approved for use in European, Australian, and Canadian guidelines since 2010, the FDA only approved their use in 2017. There is no consensus on how to compare the results from various hscTn assays. A literature review was performed to analyze the advantages and limitations of using hscTn as a standard biomarker to evaluate patients with suspected ACS in the emergency setting.

Recommendations for Institutions Transitioning to High-Sensitivity Troponin Testing: JACC Scientific Expert Panel

High-sensitivity cardiac troponin (hs-cTn) I or T methods have been in use in certain regions for years but are now increasingly globally adopted, including in the United States. Accordingly, inevitable challenges are created for institutions transitioning from conventional cardiac troponin (cTn) assays. hs-cTn assays have higher analytic precision at lower concentrations, yielding greater clinical sensitivity for myocardial injury and allowing accurate recognition of small changes in troponin concentration (rise or fall) within a short time frame. Although much of the knowledge regarding troponin biology that was applicable with older troponin assays still holds true, considerable education regarding the differences between conventional cTn and hs-cTn is needed before medical systems convert to the newer methods. This includes a basic understanding of how hs-cTn testing differs from conventional cTn testing and how it is best deployed in different settings, such as the emergency department and inpatient services. This Expert Panel will review important concepts for institutional transition to hs-cTn methodology, providing recommendations useful for education before implementation.

Cardiac Troponin - diagnostic problems and impact on cardiovascular disease

The definition of a high-sensitivity cardiac Troponin (cTn) assay describes the ability to quantify a cardiac biomarker level in at least 50% of healthy individuals. This advance in analytic sensitivity has come with a perceived loss of specificity in the most classic application - chest pain triage and the diagnosis of acute myocardial infarction (AMI). As cardiac Troponin can no longer be used as a dichotomous test, the medical field is increasingly moving towards a more granular interpretation. However, rapid rule-out/rule-in algorithms for AMI still rely on concrete thresholds for efficient triage, irrespective of the patient's comorbidities. Owing to a slightly elevated cTn value, evermore patients appear to fall into an indeterminate risk zone of diagnostic uncertainty. The reasons are manifold, spanning biological variation, analytical issues, increased plasma membrane permeability and the potential cytosolic release of cTn. This review provides a contemporary overview of the literature concerning the use of cardiac Troponin in chronic and acute cardiovascular care. Key messages High-sensitivity cardiac Troponin assays have transformed the assessment of cardiovascular disease. Rapid rule-out algorithms for chest pain triage have become increasingly complicated, but enable safe rule-out. Cardiac Troponin tracks mid- to long-term risk in patients with hyperlipidaemia, heart failure and renal dysfunction.

Sex-specific, high-sensitivity cardiac troponin T cut-off concentrations for ruling out acute myocardial infarction with a single measurement

OBJECTIVE

Sex-specific diagnostic cut-offs may improve the test characteristics of high-sensitivity troponin assays for the diagnosis of myocardial infarction (MI). The objective of this study was to quantify test characteristics of sex-specific cut-offs of a single, high-sensitivity cardiac troponin T (hs-cTnT) assay for 7-day MI in patients with chest pain.

METHODS

This observational cohort study included consecutive emergency department (ED) patients with suspected cardiac chest pain from four Canadian EDs who had an hs-cTnT assay performed within 60 minutes of ED arrival. The primary outcome was MI at 7 days. We quantified test characteristics (sensitivity, negative predictive value [NPV], likelihood ratios and proportion of patients ruled out) for multiple combinations of sex-specific, rule-out cut-offs. We calculated the net reclassification index compared to universal rule-out cut-offs.

RESULTS

In 7,130 patients (3,931 men and 3,199 women), the 7-day MI incidence was 7.38% among men and 3.78% among women. Optimal sex-specific cut-offs (<8 ng/L for men and <7 ng/L for women) had a 98.5% sensitivity for MI and ruled out MI in 55.8% of patients. This would enable an absolute increase in the proportion of patients who were able to be ruled out with a single hs-cTnT of 13.2% to 22.2%, depending on the universal rule-out concentration used as a comparator.

CONCLUSIONS

Sex-specific hs-cTnT cut-offs for ruling out MI at ED arrival may improve classification performance, enabling more patients to be safely ruled out at ED arrival. However, differences between sex-specific and universal cut-off concentrations are within the variation of the assay, limiting the clinical utility of this approach. These findings should be confirmed in other data sets.

Contemporary Emergency Department Management of Patients with Chest Pain: A Concise Review and Guide for the High-Sensitivity Troponin Era

This article synthesizes current best evidence for the evaluation of patients with suspected acute coronary syndrome (ACS) using high-sensitivity troponin assays, enabling physicians to effectively incorporate them into practice. Unlike conventional assays, high-sensitivity assays can precisely measure blood cardiac troponin concentrations in the vast majority of healthy individuals, facilitating the creation of rapid diagnostic algorithms. Very low troponin concentrations on presentation accurately rule out acute myocardial infarction (AMI) and enable the discharge of approximately 20% of patients after a single test, whereas an additional 30%-40% of patients can be safely discharged after short-interval serial sampling in as little as 1 or 2 hours. In contrast, highly abnormal troponin concentrations on presentation (more than 5 times the upper reference limit) or rapidly rising levels on serial testing can rapidly rule in AMI with high specificity. However, approximately one-third of patients remain in a biomarker-indeterminate "observation zone" even after serial sampling. These patients pose a disposition challenge to clinicians because although the differential diagnosis of elevated troponin concentrations is broad, these patients have an increased risk for short-term major adverse cardiac events. Use of repeated serial troponin sampling and structured clinical prediction tools may assist disposition for these patients, because no validated pathways currently exist to guide clinicians. Ongoing research to tailor diagnostic thresholds to individual patient characteristics may enable improved diagnostic accuracy and usher in a new era of personalized medicine in the evaluation of suspected ACS.