Cardiac troponin changes to distinguish type 1 and type 2 myocardial infarction and 180-day mortality risk.

Aims: To determine the ability of serial cardiac troponin (cTnI) changes (delta) to distinguish type 1 and type 2 myocardial infarction (MI) (excluding all ST-segment elevation MIs (STEMIs)) and describe the diagnostic accuracy and 180-day mortality in MI versus no-MI patients.

Methods And Results: Serial cTnIs were measured in 1112 consecutive patients without STEMI and within 6h of presentation to a United States emergency department: 856 (77%) with no MI, 66 (6%) type 1 MI, and 190 (17%) type 2 MI. Of the 0 to 3h and 0 to 6h absolute and relative cTnI changes, only the distribution of absolute change from 0 to 6h was significantly different between type 1 and type 2 MI: median (interquartile range) 311 (1430) ng/l vs.

Diagnostic performance of four point of care cardiac troponin I assays to rule in and rule out acute myocardial infarction.

Objective: This study evaluated the diagnostic performance of four point-of-care (POC) cardiac troponin I (cTnI) assays compared to a central laboratory cTnI assay for detecting myocardial injury and diagnosing acute myocardial infarction (AMI).

Design And Methods: Plasma obtained at admission, 3 h, and 6 h post-admission in 169 patients presenting with symptoms suggestive of acute coronary syndrome (ACS) was studied. cTnI concentrations were measured on the Instrumentation Laboratory prototype GEM Immuno, Radiometer AQT90, Mitsubishi PATHFAST, Abbott i-STAT and the Ortho-Clinical Diagnostic Vitros assays.

Determination of 19 cardiac troponin I and T assay 99th percentile values from a common presumably healthy population.

Background: Between-assay comparability of 99th percentiles for cardiac troponin concentrations has not been assessed systematically in a single population for a large number of assays.

Methods: We determined 99th percentiles for 19 cardiac troponin assays in heparin plasma samples from a population of 272 and 252 presumably healthy males and females, respectively. The assays evaluated included 1 cardiac troponin T (cTnT) assay from Roche and 18 cTnI assays from Abbott, Alere, Beckman, bioMerieux, Instrumentation Laboratory, Ortho-Clinical Diagnostics, Singulex, Siemens, and Roche.

Increased cardiac troponin I as measured by a high-sensitivity assay is associated with high odds of cardiovascular death: the Minnesota Heart Survey.

Background: We examined several novel biomarkers of different pathophysiologic pathways as predictors of cardiovascular mortality in participants enrolled in the Minnesota Heart Survey (MHS), a population-based study of cardiovascular disease (CVD) risk factors.

Methods: In a nested case-control study within MHS, 7 biomarkers were assayed in serum samples from 211 patients identified after 8-15 years of follow-up who died of cardiovascular causes (cardiovascular heart disease, stroke, congestive heart failure) and 253 controls matched on age, sex, and study year. Logistic regression analysis, adjusted for age, race, sex, education, study year, smoking, abdominal obesity, diabetes, serum total cholesterol, systolic blood pressure, previous hospitalization for a CVD event, and other significant biomarkers, was used to evaluate the relations of biomarkers relative to the odds of CVD mortality.

Myeloperoxidase improves risk stratification in patients with ischemia and normal cardiac troponin I concentrations.

Background: We assessed the ability of myeloperoxidase (MPO) to identify the risk for major adverse cardiac events (MACE) in patients who present with ischemic symptoms suggestive of acute coronary syndrome and have a normal cardiac troponin I (cTnI) value.

Methods: We used Siemens (n = 400) and Abbott (n = 350) assays to measure MPO and cTnI in plasma samples from 400 patients. Event rates (myocardial infarction, cardiac death, percutaneous coronary intervention, coronary artery bypass grafting) were estimated by the Kaplan-Meier method and compared with the log-rank statistic.

Assessment of the multiple-biomarker approach for diagnosis of myocardial infarction in patients presenting with symptoms suggestive of acute coronary syndrome.

Background: Cardiac troponin is the preferred biomarker for detecting acute myocardial injury and infarction (MI). We studied whether multiple biomarkers of numerous pathophysiological pathways would increase the diagnostic accuracy for detecting MI.

Methods: Seven biomarkers [myeloperoxidase, soluble CD40 ligand, placental growth factor, matrix metalloproteinase 9 (MMP-9), high-sensitivity C-reactive protein (hsCRP), cardiac troponin I (cTnI), N-terminal pro-B-type natriuretic peptide] and estimated glomerular filtration rate were measured in 457 patients presenting on admission with symptoms suggestive of acute coronary syndrome.

Analytical characteristics of commercial cardiac troponin I and T immunoassays in serum from rats, dogs, and monkeys with induced acute myocardial injury.

Background: Information is needed regarding analytical characteristics of cardiac troponin (cTn) assays used in preclinical studies.

Methods: We measured cTnI and cTnT in serum from normal animals and animals with induced myocardial injury [Sprague-Dawley (SD) and Wistar rats, beagle dogs, and rhesus (Rh) and cynomolgus (Cy) monkeys]. We evaluated the following assays: for cTnI, Abbott Architect, Bayer Centaur (first and second generation), Beckman Access, DPC Immulite, Dade Dimension, Ortho Vitros ES, Tosoh AIA, and species-specific enzyme immunoassays; for cTnT, Roche Elecsys.

Cardiac isoenzymes in healthy Holstein calves and calves with experimentally induced endotoxemia.

This paper describes a controlled study designed to establish normal values for cardiac troponins I and T (cTnI and cTnT) and CK-MB mass in healthy newborn Holstein calves, and to compare values for cTnI, cTnT, CK-MB and total creatine kinase (CK) with age-matched calves experiencing experimentally induced endotoxemia. Nineteen healthy Holstein bull calves, 48 to 72 h of age were used. Baseline cTnI, cTnT, CK-MB and total CK measurements were obtained from control (n = 9) and experimental (n = 10) calves.

Novel immunoassay for quantification of brain natriuretic peptide and its precursor in human blood.

Background: Brain natriuretic peptide (BNP) is an unstable molecule that can rapidly lose immunologic activity in blood. Conventional sandwich BNP immunoassays use 2 antibodies specific to 2 different epitopes. Larger distances between epitopes are associated with a greater probability of proteolysis sites being located between the antibody-binding sites, and thus such assays have an increased susceptibility to underdetect BNP because of the increased likelihood of proteolytic degradation.

Immunodetection of glycosylated NT-proBNP circulating in human blood.

Background: Brain natriuretic peptide (BNP) or NT-proBNP (N-terminal fragment of BNP precursor) measurements are recommended as aids in diagnosis and prognosis of patients with heart failure. Recently it has been shown that proBNP is O-glycosylated in human blood. The goal of this study was to map sites on the NT-proBNP molecule that should be recognized by antibodies used in optimal NT-proBNP assays.

Performance characteristics of the Architect brain natriuretic peptide (BNP) assay: a two site study.

Introduction: Brain natriuretic peptide (BNP) is produced by the ventricles of the heart and is a biomarker for heart failure. Several commercial assays are now available. We evaluated the performance characteristics of the ARCHITECT BNP assay.

Multi-center validation of the Response Biomedical Corporation RAMP NT-proBNP assay with comparison to the Roche Diagnostics GmbH Elecsys proBNP assay.

Background: NT-proBNP measurements aid in the evaluation of patients with suspected heart failure (HF) and may facilitate risk stratification in patients with HF and acute coronary syndrome (ACS). Point-of-care (POC) assays may provide more timely results and potentially improve patient outcomes.

Methods: We evaluated the analytical performance of the Response Biomedical Corporation whole blood RAMP amino-terminal pro-B type natriuretic peptide (NT-proBNP) POC assay compared to the Roche Elecsys proBNP (NT-proBNP) assay.

Multiple biomarker use for detection of adverse events in patients presenting with symptoms suggestive of acute coronary syndrome.

Background: We investigated multiple biomarkers of various pathophysiologic pathways to determine their relationships with adverse outcomes in patients presenting with symptoms of acute coronary syndrome.

Methods: We obtained plasma specimens from 457 patients on admission and measured 7 biomarkers: myeloperoxidase (MPO), soluble CD40 ligand (CD40L), placental growth factor (PlGF), metalloproteinase-9 (MMP-9), high-sensitivity C-reactive protein (hsCRP), cardiac troponin I (cTnI), and N-terminal pro-B-type natriuretic peptide (NT-proBNP). We used the Modification of Diet in Renal Disease formula to calculate the estimated glomerular filtration rate (eGFR).

Cardiac troponin risk stratification based on 99th percentile reference cutoffs in patients with ischemic symptoms suggestive of acute coronary syndrome: influence of estimated glomerular filtration rates.

Cardiac troponin (cTn) assays were compared in 490 unselected patients with symptoms suggestive of acute coronary syndrome with varying renal functions for risk stratification. cTnI (Dade, Newark, NJ; Beckman, Chaska, MN; and Tosoh, South San Francisco, CA) and cTnT (Roche, Indianapolis, IN) measurements and estimated glomerular filtration rates (eGFRs) were obtained and classified along sex-derived cutoffs. The cTn levels were increased in 14% to 25% of patients.

B-type natriuretic peptide (BNP) and N-terminal pro-BNP in obese patients without heart failure: relationship to body mass index and gastric bypass surgery.

Background: Further investigations are warranted to better characterize variables that may confound the clinical interpretation of plasma natriuretic peptide measurements, which are increasingly recognized to have diagnostic and predictive importance.

Methods: Blood samples (EDTA plasma) from patients (n = 206) attending clinics for the medical treatment and follow-up of obesity were analyzed for B-type natriuretic peptide (BNP; Bayer assay) and the N-terminal segment of its prohormone (NT-proBNP; Roche assay). Natriuretic peptide concentration ranges were evaluated in those without diagnosis of congestive heart failure (CHF) or chronic kidney disease (CKD).

Point-of-care i-STAT cardiac troponin I for assessment of patients with symptoms suggestive of acute coronary syndrome.

Background: Few studies have investigated the role of cardiac troponin point-of-care (POC) testing for predicting adverse outcomes in acute coronary syndrome (ACS) patients. We investigated the use of a POC cTnI assay in ACS patients.

Methods: We studied consecutive patients (n = 367) presenting with symptoms suggestive of ACS who were admitted through the emergency department.

Biochemical markers of cardiac injury in normal, surviving septic, or nonsurviving septic neonatal foals.

The cardiac biomarkers cardiac troponin T (cTnT) and I (cTnI) and the cardiac isoenzyme of creatine kinase (CKMB) are used extensively in human medicine to diagnose and provide valuable prognostic information in patients with ischemic, traumatic, and septic myocardial injury. We designed a study to establish normal values for these markers in healthy, neonatal foals and to compare them with values obtained from septic neonates in a referral hospital population. The 25th, 50th, 75th, and 95th percentiles for cTnI and CKMB in the healthy-foal population were 0.

The diagnostic utility of cardiac biomarkers in detecting myocardial infarction.

Cardiac biomarkers, eg, cardiac troponin, have become the standard test in combination with clinical and electrocardiographic findings for physicians to conduct prompt and effective triage of patients presenting with chest pain. Cardiac biomarkers are protein components of cell structures that are released into circulation when myocardial injury occurs. The purpose of this article is multifold.

Evaluation of a point-of-care assay for cardiac markers for patients suspected of acute myocardial infarction.

Background: Creatine kinase MB (CK-MB), and cardiac troponin I (cTnI) are important biomarkers for the diagnosis and rule-out of acute myocardial infarction (AMI) of patients who presented to the emergency department (ED) with chest pain. With new rapid ED assessment protocols, there is increasing pressure to produce results with a short turnaround time (TAT), and point-of-care (POC) testing is one alternative for providing fast results.

Methods: In a multicenter study, we evaluated the analytical precision, sensitivity and specificity of the RAMP (Response Biomedical) CK-MB and cTnI POC assays and compared results against the Triage (Biosite) POC and the Dimension RxL (Dade Behring) central-laboratory assays on 365 subjects, including 185 patients suspected of AMI, and determined the normal range on 180 healthy individuals.

Analytical performance of the i-STAT cardiac troponin I assay.

Background: This study determines the analytical characteristics of the i-STAT cardiac troponin I assay (cTnI; i-STAT, Princeton, NJ), a 10-min POC assay, designed to be performed at the bedside.

Methods: Three different hospitals participated in a patient specimen and analytical validation study (n=186) for the i-STAT cTnI assay carried out in real time. A total of 186 whole blood specimens (lithium heparin) were collected from patients presenting with symptoms suggestive of acute coronary syndromes (ACS) for correlation studies as well as from 162 healthy subjects for reference interval determination.

Diagnostic and prognostic value of cardiac troponin I assays in patients admitted with symptoms suggestive of acute coronary syndrome.

Context: Increasing numbers of patients are presenting to emergency departments with symptoms suggestive of an acute myocardial infarction.

Objective: To demonstrate the comparative performance of the Ortho Vitros Troponin I and Beckman Access AccuTnI assays used to detect myocardial infarction and to develop risk stratification schemes for all-cause death in patients who presented with myocardial ischemia symptoms that were suggestive of acute coronary syndrome (ACS).

Design: The prospective enrollment of patients with ACS and the measurement of serial plasma samples by 2 commercial cardiac troponin I (cTnI) assays.