Biomarkers for Predicting Serious Cardiac Outcomes at 72 Hours in Patients Presenting Early after Chest Pain Onset with Symptoms of Acute Coronary Syndromes

Early Prediction of All-Cause Clinical Deterioration in General Wards Patients: Development and Validation of a Biomarker-Based Machine Learning Model Derived From Rapid Response Team Activations

OBJECTIVE

The aim of the study is to evaluate the performance of a biomarker-based machine learning (ML) model (not including vital signs) derived from reviewed rapid response team (RRT) activations in predicting all-cause deterioration in general wards patients.

DESIGN

This is a retrospective single-institution study. All consecutive adult patients' cases on noncritical wards identified by RRT calls occurring at least 24 hours after patient admission, between April 2018 and June 2020, were included. The cases were reviewed and labeled for clinical deterioration by a multidisciplinary expert consensus panel. A supervised learning approach was adopted based on a set of biomarkers and demographic data available in the patient's electronic medical record (EMR).

SETTING

The setting is a 250-bed tertiary university hospital with a basic EMR, with adult (>18 y) patients on general wards.

PATIENTS

The study analyzed the cases of 514 patients for which the RRT was activated. Rapid response teams were extracted from the hospital telephone log data. Two hundred eighteen clinical deterioration cases were identified in these patients after expert chart review and complemented by 146 "nonevent" cases to build the training and validation data set.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The best performance was achieved with the random forests algorithm, with a maximal area under the receiver operating curve of 0.90 and F1 score of 0.85 obtained at prediction time T0-6h, slightly decreasing but still acceptable (area under the receiver operating curve, >0.8; F1 score, >0.75) at T0-42h. The system outperformed most classical track-and-trigger systems both in terms of prediction performance and prediction horizon.

CONCLUSIONS

In hospitals with a basic EMR, a biomarker-based ML model could be used to predict clinical deterioration in general wards patients earlier than classical track-and-trigger systems, thus enabling appropriate clinical interventions for patient safety and improved outcomes.

Can the Addition of NT-proBNP and Glucose Measurements Improve the Prognostication of High-Sensitivity Cardiac Troponin Measurements for Patients with Suspected Acute Coronary Syndrome?

Guidelines published in 2021 have supported natriuretic peptide (NP) testing for the prognostication in patients with acute coronary syndrome (ACS) and for the diagnosis of chronic and acute heart failure (HF). Our objective was to determine if the addition of N-terminal pro B-type NP (NT-proBNP) and glucose to high-sensitivity cardiac troponin (hs-cTn) could better identify emergency department (ED) patients with potential ACS at low- and high-risk for a serious cardiovascular outcome over the next 72 h. The presentation sample in two different ED cohorts which enrolled patients with symptoms suggestive of ACS within six hours of pain onset (Cohort-1, n = 126 and Cohort-2, n = 143) that had Abbott hs-cTnI, Roche hs-cTnT, NT-proBNP and glucose were evaluated for NT-proBNP alone and combined with hs-cTn and glucose for the primary outcome (composite which included death, myocardial infarction, HF, serious arrhythmia and refractory angina) via receiver-operating characteristic (ROC) curve analyses with area under the curve (AUC) and diagnostic estimates derived. The AUC for NT-proBNP for the primary outcome was 0.68 (95% confidence interval (CI): 0.59-0.76) and 0.75 (95%CI: 0.67-0.82) in Cohort-1 and 2, respectively, with the 125 ng/L cutoff yielding a higher sensitivity (≥75%) as compared to the 300 ng/L cutoff (≥58%). Using the 125 ng/L cutoff for NT-proBNP with the published glucose and hs-cTn cutoffs for risk-stratification produced a new score (GuIDER score for Glucose, Injury and Dysfunction in the Emergency-setting for cardiovascular-Risk) and yielded higher AUCs as compared to NT-proBNP (p < 0.05). GuIDER scores of 0 and 5 using either hs-cTnI/T yielded sensitivity estimates of 100% and specificity estimates > 92% for the primary outcome. A secondary analysis assessing MI alone in the overall population (combined Cohorts 1 and 2) also achieved 100% sensitivity for MI with a GuIDER cutoff ≥ 2, ruling-out 48% (Roche) and 38% (Abbott) of the population at presentation for MI. Additional studies are needed for the GuIDER score in both the acute and ambulatory setting to further refine the utility, however, the preliminary findings reported here may present a pathway forward for inclusion of NP testing for ruling-out serious cardiac events and MI in the emergency setting.

Risk Stratification for Patients with Chest Pain Discharged Home from the Emergency Department

For patients with chest pain who are deemed clinically to be low risk and discharged home from the emergency department (ED), it is unclear whether further laboratory tests can improve risk stratification. Here, we investigated the utility of a clinical chemistry score (CCS), which comprises plasma glucose, the estimated glomerular filtration rate, and high-sensitivity cardiac troponin (I or T) to generate a common score for risk stratification. In a cohort of 14,676 chest pain patients in the province of Ontario, Canada and who were discharged home from the ED (November 2012-February 2013 and April 2013-September 2015) we evaluated the CCS as a risk stratification tool for all-cause mortality, plus hospitalization for myocardial infarction or unstable angina (primary outcome) at 30, 90, and 365 days post-discharge using Cox proportional hazard models. At 30 days the primary outcome occurred in 0.3% of patients with a CCS < 2 (n = 6404), 0.9% of patients with a CCS = 2 (n = 4336), and 2.3% of patients with a CCS > 2 (n = 3936) (p < 0.001). At 90 days, patients with CCS < 2 (median age = 52y (IQR = 46-60), 59.4% female) had an adjusted HR = 0.51 (95% confidence interval (CI) = 0.32-0.82) for the composite outcome and patients with a CCS > 2 (median age = 74y (IQR = 64-82), 48.0% female) had an adjusted HR = 2.80 (95%CI = 1.98-3.97). At 365 days, 1.3%, 3.4%, and 11.1% of patients with a CCS < 2, 2, or >2 respectively, had the composite outcome (p < 0.001). In conclusion, the CCS can risk stratify chest pain patients discharged home from the ED and identifies both low- and high-risk patients who may warrant different medical care.

Determination of age- and sex-specific 99th percentiles for high-sensitive troponin T from patients: an analytical imprecision- and partitioning-based approach

BACKGROUND

Detection of acute myocardial infarction (AMI) is mainly based on a rise of cardiac troponin with at least one value above the 99th percentile upper reference limit (99th URL). However, circulating high-sensitive cardiac troponin T (hs-cTnT) concentrations depend on age, sex and renal function. Using an analytical imprecision-based approach, we aimed to determine age- and sex-specific hs-cTnT 99th URLs for patients without chronic kidney disease (CKD).

METHODS

A 3.8-year retrospective analysis of a hospital laboratory database allowed the selection of adult patients with concomitant plasma hs-cTnT (<300 ng/L) and creatinine concentrations, both assayed twice within 72 h with at least 3 h between measurements. Absence of AMI was assumed when the variation between serial hs-cTnT values was below the adjusted-analytical change limit calculated according to the inverse polynomial regression of analytical imprecision. Specific URLs were determined using Clinical and Laboratory Standards Institute (CLSI) methods, and partitioning was tested using the proportion method, after adjustment for unequal prevalences.

RESULTS

After outlier removal (men: 8.7%; women: 6.6%), 1414 men and 1082 women with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 were assumed as non-AMI. Partitioning into age groups of 18-50, 51-70 and 71-98 years, the hs-cTnT 99th URLs adjusted on French prevalence were 18, 33, 66 and 16, 30, 84 ng/L for men and women, respectively. Age-partitioning was clearly required. However, sex-partitioning was not justified for subjects aged 18-50 and 51-70 years for whom a common hs-cTnT 99th URLs of about 17 and 31 ng/L could be used.

CONCLUSIONS

Based on a laboratory approach, this study supports the need for age-specific hs-cTnT 99th URLs.

Evaluation of the Siemens ADVIA Centaur high-sensitivity cardiac troponin I assay in serum

BACKGROUND

International recommendations on high-sensitivity cardiac troponin (hs-cTn) testing recommend that laboratories select only one sample type for testing. We evaluated the Siemens ADVIA Centaur hs-cTnI assay in serum and thereby provide information on imprecision, long-term storage stability, freeze-thaw stability, method comparison to other hs-cTnI assays, and clinical performance.

METHODS

Patients with chest pain onset <6 h who already had Roche hs-cTnT, Beckman hs-cTnI and Abbott hs-cTnI results recorded and had non-thawed and frozen serum aliquots formed the study population (n = 134 patients with 305 serum aliquots obtained at either 0, 3 or 6 h stored below -70 °C since 2003) for measurement with the Siemens hs-cTnI assay in 2018. Receiver-operating characteristic curve analyses for myocardial infarction (MI) using the highest obtained hs-cTn concentration was performed. Additional comparison testing on serum samples stored frozen (at -70 °C for <1 month in 2018) for the Siemens and Abbott hs-cTnI assays were performed, as well as precision testing in serum pools and freeze-thaw stability testing.

RESULTS

The Siemens hs-cTnI assay had an area under the curve (AUC) of 0.978 (95%CI: 0.937-0.996) for MI in the study cohort (Roche hs-cTnT AUC = 0.965 and Abbott AUC = 0.973). The Siemens hs-cTnI assay yielded higher cTnI concentrations than the other hs-cTn assays, with the same proportional bias (slope = 1.4) between the Siemens and Abbott hs-cTnI assays obtained from serum samples collected in 2003 and 2018. Over 3 months, a low serum pool of 3.5 ng/l achieved a CV of 20% (SD = 0.7, n = 42) and a high serum pool of 820 ng/l achieved a CV of 2.3% (SD = 20, n = 42). Three different serum pools recovered within 10% from baseline concentration after 5 freeze-thaw cycles for the Siemens hs-cTnI assay.

CONCLUSIONS

In serum, the Siemens ADVIA Centaur hs-cTnI assay had excellent clinical performance for MI in an early chest pain onset population, acceptable precision at normal and highly elevated cTnI concentrations, long-term storage stability (15 y storage below -70 °C) and acceptable freeze-thaw stability, all of which supports serum as an acceptable sample type to use in clinical studies and in clinical practice.

5th generation cardiac troponin I and T assays in clinical routine - A head-to-head comparison with data from the Linz troponin (LITROP) study

BACKGROUND

In Europe, clinicians use so called high-sensitivity assays for the measurement of cardiac troponin I and T (i.e., hs-cTnI and hs-cTnT assays, also termed 5th generation assays) since several years. We aimed at performing a head-to-head comparison of two 5th generation assays in "real life use".

METHODS

We studied 3588 consecutive patients presenting to an emergency department. We used both, a hs-cTnI assay from Abbott and a hs-cTnT assay from Roche in clinical routine. We assessed (1) the capabilities of hs-cTnI and hs-cTnT for the prediction of 3.7 year all-cause mortality; (2) discordant diagnoses of myocardial injury by hs-cTnI and hs-cTnT according to the European gender-neutral 99th percentile upper reference limits (i.e., 26 ng/L and 14 ng/L, respectively); and (3) analyte kinetics in patient with serial troponin measurements.

RESULTS

With respect to prognosis of all-cause mortality, the AUC of hs-cTnI was 0.81 (95% CI, 0.80-0.82), and the AUC of hs-cTnT was 0.85 (95% CI, 0.84-0.86). With respect to discordant diagnoses, 21% of the 3588 patients were classified as having myocardial injury by hs-cTnT but not by hs-cTnI, and < 1% were classified as having myocardial injury by hs-cTnI but not by hs-cTnT. In the patients with serial blood sampling, the median delta values were 6.3 ng/L and 25% for hs-cTnI, and 4.2 ng/L and 16% for hs-cTnT.

CONCLUSION

We found different characteristics of the Abbott hs-cTnI and the Roche hs-cTnT assays, especially when using the European gender-neutral 99th percentile upper reference limits. Clinically, these different characteristics are related to discordant results in the diagnosis and prognosis of patients presenting to an emergency department.

Assessing matrix, interferences and comparability between the Abbott Diagnostics and the Beckman Coulter high-sensitivity cardiac troponin I assays

Background:

Analytical evaluation of high-sensitivity cardiac troponin (hs-cTn) assays, with particular attention to imprecision, interferences and matrix effects, at normal cTn concentrations, is of utmost importance as many different clinical algorithms use concentration cutoffs <10 ng/L for decision-making. The objective for the present analytical study was to compare the new Beckman Coulter hs-cTnI assay (Access hsTnI) to Abbott’s hs-cTnI assay in different matrices and for different interferences, with a focus on concentrations <10 ng/L.

Methods:

The limit of blank (LoB) and the limit of detection (LoD) were determined in different matrices for the Beckman hs-cTnI assay. Passing-Bablok regression and difference plots were determined for 200 matched lithium heparin and EDTA plasma samples for the Beckman assay and 200 lithium heparin samples for the Abbott assay. Both EDTA and heparin plasma samples were also evaluated for stability under refrigerated conditions, for endogenous alkaline phosphatase interference and for hemolysis and icterus.

Results:

The Beckman hs-cTnI assay LoB was 0.5 ng/L with the following range of LoDs=0.8–1.2 ng/L, with EDTA plasma yielding lower concentrations as compared to lithium heparin plasma (mean difference=−14.9%; 95% CI=−16.9 to 12.9). Below 10 ng/L, lithium heparin cTnI results from the Beckman assay were on average 1.1 ng/L (95% CI=0.7 to 1.5) higher than the Abbott results, with no difference between the methods when using EDTA plasma (mean difference =−0.1 ng/L; 95% CI=−0.3 to 0.2). Low cTnI concentrations were less effected by interferences in EDTA plasma.

Conclusions:

The Access hsTnI method can reliably detect normal cTnI concentrations with both lithium heparin and EDTA plasma being suitable matrices.

High-sensitivity troponin assays for the early rule-out or diagnosis of acute myocardial infarction in people with acute chest pain: a systematic review and cost-effectiveness analysis

BACKGROUND

Early diagnosis of acute myocardial infarction (AMI) can ensure quick and effective treatment but only 20% of adults with emergency admissions for chest pain have an AMI. High-sensitivity cardiac troponin (hs-cTn) assays may allow rapid rule-out of AMI and avoidance of unnecessary hospital admissions and anxiety.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of hs-cTn assays for the early (within 4 hours of presentation) rule-out of AMI in adults with acute chest pain.

METHODS

Sixteen databases, including MEDLINE and EMBASE, research registers and conference proceedings, were searched to October 2013. Study quality was assessed using QUADAS-2. 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 (QALYs) associated with different troponin (Tn) testing methods. The de novo model consisted of a decision tree and Markov model. A lifetime time horizon (60 years) was used.

RESULTS

Eighteen studies were included in the clinical effectiveness review. The optimum strategy, based on the Roche assay, used a limit of blank (LoB) threshold in a presentation sample to rule out AMI [negative likelihood ratio (LR-) 0.10, 95% confidence interval (CI) 0.05 to 0.18]. Patients testing positive could then have a further test at 2 hours; a result above the 99th centile on either sample and a delta (Δ) of ≥ 20% has some potential for ruling in an AMI [positive likelihood ratio (LR+) 8.42, 95% CI 6.11 to 11.60], whereas a result below the 99th centile on both samples and a Δ of < 20% can be used to rule out an AMI (LR- 0.04, 95% CI 0.02 to 0.10). The optimum strategy, based on the Abbott assay, used a limit of detection (LoD) threshold in a presentation sample to rule out AMI (LR- 0.01, 95% CI 0.00 to 0.08). Patients testing positive could then have a further test at 3 hours; a result above the 99th centile on this sample has some potential for ruling in an AMI (LR+ 10.16, 95% CI 8.38 to 12.31), whereas a result below the 99th centile can be used to rule out an AMI (LR- 0.02, 95% CI 0.01 to 0.05). In the base-case analysis, standard Tn testing was both most effective and most costly. Strategies considered cost-effective depending upon incremental cost-effectiveness ratio thresholds were Abbott 99th centile (thresholds of < £6597), Beckman 99th centile (thresholds between £6597 and £30,042), Abbott optimal strategy (LoD threshold at presentation, followed by 99th centile threshold at 3 hours) (thresholds between £30,042 and £103,194) and the standard Tn test (thresholds over £103,194). The Roche 99th centile and the Roche optimal strategy [LoB threshold at presentation followed by 99th centile threshold and/or Δ20% (compared with presentation test) at 1-3 hours] were extendedly dominated in this analysis.

CONCLUSIONS

There is some evidence to suggest that hs-CTn testing may provide an effective and cost-effective approach to early rule-out of AMI. Further research is needed to clarify optimal diagnostic thresholds and testing strategies.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005939.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Emerging families of biomarkers for coronary artery disease: inflammatory mediators

Introduction

Inflammation has been implicated in the development of atherosclerosis in patients with acute coronary syndrome. C-reactive protein is an established nonspecific prognostic inflammatory biomarker for patients with acute coronary syndrome in the medical literature. This has led to a concerted effort to identify circulating inflammatory biomarkers to facilitate predicting the risk for and diagnosing coronary artery disease in at-risk subjects. The objective of this study was to search after novel inflammatory biomarkers reported as useful for diagnosing coronary artery disease.

Methods

The PubMed database was searched for reports published from January 1, 2000 to June 30, 2012 of novel circulating biomarkers for coronary artery disease in addition to the established biomarker, C-reactive protein. The search terms used were “infarction”, “biomarkers”, and “markers”, and only original articles describing clinical trials that were written in English were included. All published articles were separately examined carefully after novel inflammatory markers for acute coronary syndrome. All irrelevant publications without content pertaining to inflammatory biomarkers for acute coronary syndrome were excluded from this study. Our results reflect all articles concerning biomarkers in humans.

Results

The PubMed search yielded 4,415 research articles. After further analysis, all relevant published original articles examining 53 biomarkers were included in this review, which identified 46 inflammation biomarkers useful for detecting coronary artery disease.

Conclusion

The emergence of diverse novel biomarkers for coronary artery disease has provided insight into the varied pathophysiology of this disease. Inflammatory biomarkers have tremendous potential in aiding the prediction of acute coronary syndrome and recurrent ischemic episodes, and will eventually help improve patient care and management.

For a rapid diagnosis of acute myocardial infarction, a sensitive troponin assay is needed in the near-patient testing setting

An early diagnosis of myocardial infarction in the emergency setting would be advantageous for both patients and the physicians treating these patients. Guidelines currently recommend serial samples that are drawn at presentation and 6-9 h later to be measured for cardiac troponin to aid in this diagnosis. However, much effort has been directed to decrease the time to make a diagnosis in this setting, and there has been renewed interest in shortening the time between serial measurements as well as the turnaround time for reporting the results. By eliminating the blood sample transit time to the central laboratory, point-of-care testing or near-patient testing can reduce the turnaround time for reporting the results, however this is possibly at the cost of decreased diagnostic performance. In this article, we discuss the recent results from the RATPAC study, which evaluated whether the combination of myoglobin, the MB isoenzyme of creatine kinase (CKMB) and a sensitive troponin assay would be superior to troponin alone.

Clinical Use and Measurement of Cardiac Troponin (cTn)

Cardiac troponins are cardio-specific and are widely used for the early diagnosis and triage of patients with acute coronary syndromes in conjunction with clinical history, electrocardiographic changes and imaging. Troponin is also useful for the prediction of outcomes in acute coronary syndromes, renal failure, sepsis, and critically ill patients. New developments in assay technology, designated as high sensitivity troponins, permit detection of lower levels of troponin in most healthy individuals, earlier diagnosis of myocardial infarction, and prognosis of stable coronary disease in the community.