scholarly journals Biochemical Markers of Acute Myocardial Infarction: Strategies for Improving Their Clinical Usefulness

1998 ◽  
Vol 35 (3) ◽  
pp. 393-399 ◽  
Author(s):  
Ian A Katz ◽  
Les Irwig ◽  
John D Vinen ◽  
Lyn March ◽  
Lindsay E Wyndham ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Logistic Regression ◽  
Chest Pain ◽  
Troponin T ◽  
Mass Measurement ◽  
World Health ◽  
Likelihood Ratios ◽  
Significant Independent Predictor ◽  
Activity Measurements

We investigated the early diagnostic utility, including incremental value, of the serum cardiac markers creatine kinase (CK), CK-MB (mass and activity measurements), cardiac troponin T, and myoglobin in the diagnosis of acute myocardial infarction (AMI) in patients presenting to a major teaching hospital with chest pain and non-diagnostic electrocardiographs (ECG). The reference diagnosis of acute myocardial infarction was made by a single, independent cardiologist using World Health Organization criteria. CK and CK-MB mass were the only significant predictors of AMI at presentation to the Emergency Department. Logistic regression analysis revealed that CK did not significantly predict ( P = 0·23) myocardial infarction once CK-MB mass was in the model. Using test results on follow up, in addition to presentation CK-MB mass, change in CK-MB mass was the only other significant independent predictor of AMI. Likelihood ratios for various levels of the significant markers in the logistic regression are given. In conclusion, CK-MB mass measurement was the only useful serum cardiac marker for the diagnosis of AMI in patients presenting with chest pain with non-diagnostic ECGs.

scholarly journals Use of Circulating MicroRNAs to Diagnose Acute Myocardial Infarction

2012 ◽  
Vol 58 (3) ◽  
pp. 559-567 ◽  
Author(s):  
Yvan Devaux ◽  
Mélanie Vausort ◽  
Emeline Goretti ◽  
Petr V Nazarov ◽  
Francisco Azuaje ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Chest Pain ◽  
Troponin T ◽  
Correct Diagnosis ◽  
Patient Treatment ◽  
Healthy Controls ◽  
Clinical Model ◽  
Acute Mi ◽  
St Elevation

Abstract BACKGROUND Rapid and correct diagnosis of acute myocardial infarction (MI) has an important impact on patient treatment and prognosis. We compared the diagnostic performance of high-sensitivity cardiac troponin T (hs-cTnT) and cardiac enriched microRNAs (miRNAs) in patients with MI. METHODS Circulating concentrations of cardiac-enriched miR-208b and miR-499 were measured by quantitative PCR in a case-control study of 510 MI patients referred for primary mechanical reperfusion and 87 healthy controls. RESULTS miRNA-208b and miR-499 were highly increased in MI patients (>105-fold, P < 0.001) and nearly undetectable in healthy controls. Patients with ST-elevation MI (n= 397) had higher miRNA concentrations than patients with non–ST-elevation MI (n = 113) (P < 0.001). Both miRNAs correlated with peak concentrations of creatine kinase and cTnT (P < 10−9). miRNAs and hs-cTnT were already detectable in the plasma 1 h after onset of chest pain. In patients who presented <3 h after onset of pain, miR-499 was positive in 93% of patients and hs-cTnT in 88% of patients (P= 0.78). Overall, miR-499 and hs-cTnT provided comparable diagnostic value with areas under the ROC curves of 0.97. The reclassification index of miR-499 to a clinical model including several risk factors and hs-cTnT was not significant (P = 0.15). CONCLUSION Circulating miRNAs are powerful markers of acute MI. Their usefulness in the establishment of a rapid and accurate diagnosis of acute MI remains to be determined in unselected populations of patients with acute chest pain.

scholarly journals Predictive Value of a 6-Hour Ecg/Troponin Protocol in Patients with Chest Pain

2003 ◽  
Vol 10 (3) ◽  
pp. 146-152 ◽  
Author(s):  
CY Man ◽  
PA Cameron ◽  
WL Cheung
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Acute Coronary Syndrome ◽  
Chest Pain ◽  
Troponin T ◽  
Low Risk ◽  
Chinese Patients ◽  
Initial Assessment ◽  
Coronary Syndrome ◽  
Pain Patients

Introduction Patients presenting with chest pain and considered to be at low risk of acute coronary syndrome (ACS) may still have coronary heart disease. The potential risk of sudden cardiac death due to arrhythmias or progression to acute myocardial infarction still exists. To minimize this risk, we have designed a 6-hour risk stratification protocol for patients with a low risk of acute myocardial infarction on initial assessment in the Accident and Emergency Department (AED). Materials & Methods This was a retrospective observational study with the aim of determining the risk of adverse cardiovascular events in chest pain patients attending an AED. These patients were subject to an ECG and cardiac troponin T tests (cTnT) at 0 hour and at 6 hours (if the two tests were negative at 0 hour), and were put under observation in the AED observation ward during the same period. The main outcome measures were adverse cardiac events at 30 days. Results A total of 371 Chinese patients considered to have low risk of ACS were recruited into the protocol. Troponin T tested positive in 19 patients (5.1%) at 0 hour and 8 patients (2.2%) at 6 hours. Amongst the 332 patients that were discharged directly from the AED, there were no re-admissions for cardiac-related deaths, acute myocardial infarction, arrhythmia or heart failure. Conclusion The 6-hour ECG and troponin T observation protocol is a useful tool to allow safe discharge of chest pain patients who are at low risk of acute coronary syndrome.

scholarly journals Machine-learning to Improve Prediction of Mortality following Acute Myocardial Infarction: An Assessment in the NCDR-Chest Pain-Myocardial Infarction Registry

2019 ◽  
Author(s):  
Rohan Khera ◽  
Julian Haimovich ◽  
Nate Hurley ◽  
Robert McNamara ◽  
John A Spertus ◽  
...  
Keyword(s):  
Machine Learning ◽  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Logistic Regression ◽  
Chest Pain ◽  
High Risk ◽  
Hospital Mortality ◽  
Gradient Descent ◽  
Machine Learning Methods ◽  
C Statistic

ABSTRACTIntroductionAccurate prediction of risk of death following acute myocardial infarction (AMI) can guide the triage of care services and shared decision-making. Contemporary machine-learning may improve risk-prediction by identifying complex relationships between predictors and outcomes.Methods and ResultsWe studied 993,905 patients in the American College of Cardiology Chest Pain-MI Registry hospitalized with AMI (mean age 64 ± 13 years, 34% women) between January 2011 and December 2016. We developed and validated three machine learning models to predict in-hospital mortality and compared the performance characteristics with a logistic regression model. In an independent validation cohort, we compared logistic regression with lasso regularization (c-statistic, 0.891 [95% CI, 0.890-0.892]), gradient descent boosting (c-statistic, 0.902 [0.901-0.903]), and meta-classification that combined gradient descent boosting with a neural network (c-statistic, 0.904 [0.903-0.905]) with traditional logistic regression (c-statistic, 0.882 [0.881-0.883]). There were improvements in classification of individuals across the spectrum of patient risk with each of the three methods; the meta-classifier model – our best performing model - reclassified 20.9% of individuals deemed high-risk for mortality in logistic regression appropriately as low-to-moderate risk, and 8.2% of deemed low-risk to moderate-to-high risk based consistent with the actual event rates.ConclusionsMachine-learning methods improved the prediction of in-hospital mortality for AMI compared with logistic regression. Machine learning methods enhance the utility of risk models developed using traditional statistical approaches through additional exploration of the relationship between variables and outcomes.

scholarly journals LO61: Test characteristics of high sensitivity troponin T performed at emergency department arrival for acute myocardial infarction in patients with reduced kidney function

CJEM ◽  
2018 ◽  
Vol 20 (S1) ◽  
pp. S28-S28
Author(s):  
A. D. McRae ◽  
S. Vatanpour ◽  
J. Ji ◽  
H. Yang ◽  
D. Southern ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Emergency Department ◽  
Chest Pain ◽  
Troponin T ◽  
High Sensitivity ◽  
Test Characteristics ◽  
High Sensitivity Troponin ◽  
High Sensitivity Troponin T ◽  
Rule Out

Introduction: Patients with chronic kidney disease (CKD) are at high risk of cardiovascular events, and have worse outcomes following acute myocardial infarction (AMI). Cardiac troponin is often elevated in CKD, making the diagnosis of AMI challenging in this population. We sought to quantify test characteristics for AMI of a high-sensitivity troponin T (hsTnT) assay performed at emergency department (ED) arrival in CKD patients with chest pain, and to derive rule-out cutoffs specific to patient subgroups stratified by estimated glomerular filtration rate (eGFR). We also quantified the sensitivity and classification performance of the assays limit of detection (5 ng/L) and the FDA-approved limit of quantitation (6 ng/L) for ruling out AMI at ED arrival. Methods: Consecutive patients in four urban EDs from the 2013 calendar year with suspected cardiac chest pain who had a Roche Elecsys hsTnT assay performed on arrival were included f. This analysis was restricted to patients with an eGFR< 60 ml/min/1.73m2. The primary outcome was 7-day AMI. Secondary outcomes included major adverse cardiac events (death, AMI and revascularization). Test characteristics were calculated and ROC curves were generated for eGFR subgroups. Results: 1416 patients were included. 7-day AMI incidence was 10.1%. 73% of patients had an initial hsTnT concentration greater than the assays 99th percentile (14 ng/L). TCurrently accepted cutoffs to rule out MI at ED arrival ( 5 ng/L and 6 ng/L) had 100% sensitivity for AMI, but no patients with an eGFR less than 30 ml/min/1.73M had hsTnT concentrations below these thresholds. We derived eGFR-adjusted cutoffs to rule out MI with sensitivity >98% at ED arrival, which were able to rule out 6-42% of patients, depending on eGFR category. The proportion of patients able to be accurately ruled-in with a single hsTnT assay was substantially lower among patients with an eGFR <30 ml/min/1.73m2 (6-20% vs 25-43%). We also derived eGFR-adjusted cutoffs to rule-in AMI with specificity >90%, which accurately ruled-in up to 18% of patients. Conclusion: Cutoffs achieving acceptable diagnostic performance for AMI using single hsTnT sampling on ED arrival may have limited clinical utility, particularly among patients with very low eGFR. The ideal diagnostic strategy for AMI in patients with CKD likely involves serial high-sensitivity troponin testing with diagnostic thresholds customized to different eGFR categories.

scholarly journals Incremental Value of High-Sensitivity Cardiac Troponin T for Risk Prediction in Patients with Suspected Acute Myocardial Infarction

2011 ◽  
Vol 57 (9) ◽  
pp. 1318-1326 ◽  
Author(s):  
Willibald Hochholzer ◽  
Tobias Reichlin ◽  
Raphael Twerenbold ◽  
Claudia Stelzig ◽  
Kirsten Hochholzer ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Chest Pain ◽  
Risk Score ◽  
Cardiac Troponin ◽  
Troponin T ◽  
Acute Chest Pain ◽  
High Sensitivity ◽  
Cardiac Troponin T ◽  
Coronary Syndrome

BACKGROUND High-sensitivity cardiac troponin assays have better analytical precision and sensitivity than earlier-generation assays when measuring cardiac troponin at low concentrations. We evaluated whether use of a high-sensitivity assay could further improve risk stratification compared with a standard cardiac troponin assay. METHODS We enrolled consecutive patients presenting with acute chest pain, 30% of whom were diagnosed with acute coronary syndrome. Blood samples were drawn at the time of presentation. We measured cardiac troponin T with a standard fourth-generation assay (cTnT) and a high-sensitivity assay (hs-cTnT) (both Roche Diagnostics) and followed the patients for 24 months. RESULTS Of the 1159 patients, 76 died and 42 developed an acute myocardial infarction (AMI). Prognostic accuracy of hs-cTnT for death was significantly higher [area under ROC curve (AUC) 0.79, 95% CI 0.74–0.84] than that of cTnT (AUC 0.69, 95% CI 0.62–0.76; P &lt; 0.001). After adjustment for Thrombolysis in Myocardial Infarction (TIMI) risk score (that included the cTnT assay result), hs-cTnT above the 99th percentile (0.014 μg/L) was associated with a hazard ratio for death of 2.60 (95% CI 1.42–4.74). Addition of hs-cTnT to the risk score improved the reclassification of patients (net reclassification improvement 0.91; 95% CI 0.67–1.14; P &lt; 0.001). Subgroup analyses showed that this effect resulted from the better classification of patients without AMI at time of testing. hs-cTnT outperformed cTnT in the prediction of AMI during follow-up (P=0.02), but was not independently predictive for this endpoint. CONCLUSIONS Concentrations of hs-cTnT &gt;0.014 μg/L improve the prediction of death but not subsequent AMI in unselected patients presenting with acute chest pain.

scholarly journals Serial Sampling of High-Sensitivity Cardiac Troponin T May Not Be Required for Prediction of Acute Myocardial Infarction Diagnosis in Chest Pain Patients with Highly Abnormal Concentrations at Presentation

2017 ◽  
Vol 63 (2) ◽  
pp. 542-551 ◽  
Author(s):  
Matthias Mueller-Hennessen ◽  
Christian Mueller ◽  
Evangelos Giannitsis ◽  
Moritz Biener ◽  
Mehrshad Vafaie ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Chest Pain ◽  
Cardiac Troponin ◽  
Troponin T ◽  
High Sensitivity ◽  
Final Diagnosis ◽  
Cardiac Troponin T ◽  
Blood Concentrations ◽  
Pain Patients

Abstract BACKGROUND Guidelines for diagnosing acute myocardial infarction (AMI) recommend adding kinetic changes to the initial cardiac troponin (cTn) blood concentration to improve AMI diagnosis. We hypothesized that kinetic changes may not be required in patients presenting with highly abnormal cTn. METHODS Patients presenting with suspected AMI to the emergency department were enrolled in a prospective diagnostic study. We assessed the positive predictive value (PPV) of initial high-sensitivity cardiac troponin T (hs-cTnT) blood concentrations alone and in combination with kinetic changes for AMI. Predefined relative changes (δ change of ≥20%) and absolute changes (Δ change ≥9.2 ng/L) within different time intervals (1 h, 2 h, and 4–14 h after presentation) were assessed. The final diagnosis was adjudicated by 2 independent cardiologists. RESULTS Among 1282 patients, 213 (16.6%) patients had a final diagnosis of AMI. For AMI prediction, PPVs increased from 48.8% for an initial hs-cTnT &gt;14 ng/L to 87.2% for &gt;60 ng/L, whereas PPVs remained unchanged for higher hs-cTnT concentrations at baseline (87.1% for both &gt;80 ng/L and &gt;100 ng/L). With addition of 20% relative Δ change, PPVs were not further improved in patients with baseline hs-cTnT &gt;80 ng/L using the 1-h (84.0%) and 2-h (88.9%) intervals, and only minimally when extending the interval to 4–14 h (91.2% for &gt;80 ng/L and 90.4% for &gt;100 ng/L, respectively). Similar findings were observed when applying absolute changes. CONCLUSIONS In chest pain patients with highly abnormal hs-cTnT concentrations at presentation, subsequent blood draws may not be required, as they do not provide incremental diagnostic value for prediction of AMI diagnosis.

LO57: Very low concentrations of high-sensitivity troponin T at presentation can rapidly exclude acute myocardial infarction in a significant proportion of ED chest pain patients

CJEM ◽  
2018 ◽  
Vol 20 (S1) ◽  
pp. S26-S27
Author(s):  
J. E. Andruchow ◽  
T. S. Boyne ◽  
S. Vatanpour ◽  
D. Wang ◽  
A. D. McRae
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Chest Pain ◽  
Emergency Physician ◽  
Troponin T ◽  
High Sensitivity ◽  
High Sensitivity Troponin ◽  
Low Concentrations ◽  
High Sensitivity Troponin T ◽  
Pain Patients

Introduction: Chest pain is one of the most common presenting complaints to emergency departments (EDs) across the world, and the exclusion of acute myocardial infarction (AMI) using troponin testing is central to the care of many of these patients. While testing strategies using conventional troponin assays require repeat testing over many hours to avoid missed diagnoses, high-sensitivity troponin (hs-cTn) assays may be able to exclude AMI in a large proportion of patients with a single result at presentation. This objective of this study is to validate the ability of very low concentrations of hs-cTn at presentation to exclude AMI in ED chest pain patients. Methods: This prospective cohort study was conducted at a single urban tertiary center and regional percutaneous coronary intervention site in Calgary, Alberta. Patients were eligible for enrolment if they presented to the ED with chest pain, were 25-years or older and required biomarker testing to rule out AMI at the discretion of the attending emergency physician. Patients were excluded if they had clear acute ischemic ECG changes, new arrhythmia or renal failure requiring hemodialysis. A high-sensitivity troponin result (Roche Elecsys hs-cTnT) was obtained in all patients at presentation. The primary outcome was AMI on the index visit. Secondary outcomes included 30-day AMI and major adverse cardiac events (MACE - including AMI, revascularization or cardiac death). Electronic medical records were reviewed and telephone follow-up was obtained for all patients at 30-days to ensure relevant events were captured. Two physician adjudication (board-certified emergency physician and cardiologist) was obtained for all outcomes. This study was REB approved. Results: A total of 1,167 patients were enrolled from August 2014 September 2016, of which 191 (16.3%) patients had an initial troponin below the limit of blank (LoB, <3 ng/L) and 416 (32.8%) were below the limit of detection (LoD, <5 ng/L). The sensitivity of a single troponin below the LoB (<3 ng/L) for index AMI was 100% (95% CI 96.2%-100%) and for 30-day AMI was 100% (95% CI 96.4-100%). The sensitivity of a troponin below the LoD (<5 ng/L) for index AMI was 97.9% (95% CI 92.7%-99.8%) and for 30-day AMI was 98.0% (95% CI 93.0-99.8%). Sensitivity for 30-day MACE at both cutoffs was lower: 98.4% (95% CI 94.3-99.8%) for <3 ng/L, and 94.4% (95% CI 88.8-97.7%) for <5 ng/L, respectively; however, negative predictive values remained high at both cutoffs: <3 ng/L, 99.0% (95% CI 96.3-99.9%) and <5 ng/L, 98.3% (95% CI 96.6-99.3%). Conclusion: A high sensitivity troponin T result below the LoB (<3 ng/L) is highly sensitive for excluding AMI and identifies patients at low risk of 30-day MACE. A result below the LoB (<5 ng/L) will identify a larger population of patients as low risk but has a greater risk of missed AMI and MACE.

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