Cardiaal troponine

Measurement of cardiac troponins (cTnT and cTnI), the only cardiac specific biomarkers available, is the gold standard in diagnosing acute coronary syndrome. Due to the recent introduction of more sensitive methods i.e. the high-sensitivity troponin assays, the diagnostic cut-off concentrations have very recently been established. We describe two male patients who presented at the emergency department with acute chest pain, but in whom clear evidence for a myocardial infarction in the ST segment of the EKG was lacking. Case 1 illustrates that such assays enable the earlier diagnosis of acute myocardial infarction. Case 2 shows that the diagnosis of acute myocardial infarction should be accompanied by a typical rise or fall of troponin concentrations. The latest insights into high-sensitivity cardiac troponin assays are discussed in this article. We focus specifically on sensitivity and specificity, reference values obtained from a healthy control group, and the reference change value required to detect acute myocardial infarction

A comprehensive review of upper reference limits reported for (high-)sensitivity cardiac troponin assays: The challenges that lie ahead

Cardiac troponins (cTn) are the preferred markers for the diagnosis of acute myocardial infarction (AMI). The guidelines recommend the use of the 99th percentile upper reference concentration of a healthy population as the diagnostic cut-off for AMI. However, a broad range of upper reference limits is still employed, complicating the diagnosis of AMI. This overview is meant to assist laboratory specialists to define an appropriate cut-off value for the diagnosis of AMI. Therefore, we provide an overview of the analytical performance and upper reference limits of seven (high-)sensitivity cTn assays: Roche high-sensitivity cTnT and ADVIA Centaur, Stratus CS, Dimension Vista, Vitros ECi, Access and Architect cTnI assays. It is shown that none of the reference populations completely met the guidelines, including those in package inserts. Forty percent of the studies collected less than the advised minimum of 300 subjects. Many studies (50%) did not report their inclusion criteria, while lower 99th percentile limits were observed when more stringent selection criteria were applied. Higher troponin cut-offs were found in men and elderly subjects, suggesting sex- and age-specific cut-offs would be considered. Therefore, there is still need for a large, rigorously screened reference population to more accurately establish cTn upper reference limits

Time- and temperature-dependent stability of troponin standard reference material 2921 in serum and plasma

Afdeling Klinische Chemie en Laboratoriumgeneeskunde (AKCL

High-sensitivity cardiac troponin t: Risk stratification tool in patients with symptoms of chest discomfort

BACKGROUND: Recent studies have demonstrated the association between increased concentrations of high-sensitivity cardiac troponin T (hs-cTnT) and the incidence of myocardial infarction, heart failure, and mortality. However, most prognostic studies to date focus on the value of hs-cTnT in the elderly or general population. The value of hs-cTnT in symptomatic patients visiting the outpatient department remains unclear. The aim of this study was to investigate the prognostic value of hs-cTnT as a biomarker in patients with symptoms of chest discomfort suspected for coronary artery disease and to assess its additional value in combination with other risk stratification tools in predicting cardiac events. METHODS: We studied 1,088 patients (follow-up 2.2 +/- 0.8 years) with chest discomfort who underwent coronary calcium scoring and coronary CT-angiography. Traditional cardiovascular risk factors and concentrations of hs-cTnT, N-terminal pro-brain-type natriuretic peptide (NT-proBNP) and high-sensitivity C-reactive protein (hsCRP) were assessed. Study endpoint was the occurrence of late coronary revascularization (>90 days), acute coronary syndrome, and cardiac mortality. RESULTS: Hs-cTnT was a significant predictor for the composite endpoint (highest quartile [Q4]>6.7 ng/L, HR 3.55; 95%CI 1.88-6.70; P<0.001). Survival analysis showed that hs-cTnT had significant predictive value on top of current risk stratification tools (Chi-square change P<0.01). In patients with hs-cTnT in Q4 versus <Q4, a 2- to 3-fold increase in cardiovascular risk was noticed, either when corrected for high or low Framingham risk score, coronary calcium scoring, or CT-angiography assessment (HR 3.11; 2.73; 2.47; respectively; all P<0.01). This was not the case for hsCRP and NT-proBNP. CONCLUSIONS: Hs-cTnT is a useful prognostic biomarker in patients with chest discomfort suspected for coronary artery disease. In addition, hs-cTnT was an independent predictor for cardiac events when corrected for cardiovascular risk profiling, calcium score and CT-angiography results

High-sensitivity cardiac troponin t: Risk stratification tool in patients with symptoms of chest discomfort

BACKGROUND: Recent studies have demonstrated the association between increased concentrations of high-sensitivity cardiac troponin T (hs-cTnT) and the incidence of myocardial infarction, heart failure, and mortality. However, most prognostic studies to date focus on the value of hs-cTnT in the elderly or general population. The value of hs-cTnT in symptomatic patients visiting the outpatient department remains unclear. The aim of this study was to investigate the prognostic value of hs-cTnT as a biomarker in patients with symptoms of chest discomfort suspected for coronary artery disease and to assess its additional value in combination with other risk stratification tools in predicting cardiac events. METHODS: We studied 1,088 patients (follow-up 2.2 +/- 0.8 years) with chest discomfort who underwent coronary calcium scoring and coronary CT-angiography. Traditional cardiovascular risk factors and concentrations of hs-cTnT, N-terminal pro-brain-type natriuretic peptide (NT-proBNP) and high-sensitivity C-reactive protein (hsCRP) were assessed. Study endpoint was the occurrence of late coronary revascularization (>90 days), acute coronary syndrome, and cardiac mortality. RESULTS: Hs-cTnT was a significant predictor for the composite endpoint (highest quartile [Q4]>6.7 ng/L, HR 3.55; 95%CI 1.88-6.70; P<0.001). Survival analysis showed that hs-cTnT had significant predictive value on top of current risk stratification tools (Chi-square change P<0.01). In patients with hs-cTnT in Q4 versus <Q4, a 2- to 3-fold increase in cardiovascular risk was noticed, either when corrected for high or low Framingham risk score, coronary calcium scoring, or CT-angiography assessment (HR 3.11; 2.73; 2.47; respectively; all P<0.01). This was not the case for hsCRP and NT-proBNP. CONCLUSIONS: Hs-cTnT is a useful prognostic biomarker in patients with chest discomfort suspected for coronary artery disease. In addition, hs-cTnT was an independent predictor for cardiac events when corrected for cardiovascular risk profiling, calcium score and CT-angiography results

Haemodialysis patients longitudinally assessed by highly sensitive cardiac troponin T and commercial cardiac troponin T and cardiac troponin I assays.

BACKGROUND: Elevated cardiac troponin (cTn) concentrations predict an increased mortality in patients suffering from end-stage renal disease (ESRD). This study compares the performance of a precommercial high-sensitive cTnT assay (hs-cTnT) with two contemporary cTn assays in detecting cTn elevations in ESRD patients during a six-month follow-up. METHODS: Thirty-two ESRD patients were followed for six months, during which cTn concentrations were assessed every two months. Baseline biomarker concentrations were compared with those in a simultaneously measured reference population of 501 healthy subjects. RESULTS: During follow-up 26 (81%), 32 (100%) and 9 (28%) of the patients showed elevated cTn concentrations according to the current cTnT, the hs-cTnT and the cTnI assays, respectively. The range of concentrations measured in each patient had a median (interquartile range) magnitude of 0.03 mug/L (0.02-0.06), 0.017 mug/L (0.011-0.029) and 0.011 mug/L (0-0.017) according to the aforementioned assays. CONCLUSION: According to the hs-cTnT assay, all of the ESRD patients had elevated cTnT concentrations at least once during the follow-up. As elevated cTn concentrations are highly prognostic of adverse events, the use of serial measurements has thus identified additional patients at risk for such events. The fact that we find cTn concentrations to be higher in patients with a history of cardiac disease is in line with this. Additional studies in ESRD patients are needed to investigate the added diagnostic and prognostic value of the very low cTnT concentrations and variations detected only by the hs-cTnT assay

Inflammation, overhydration and cardiac biomarkers in haemodialysis patients: a longitudinal study.

BACKGROUND: Inflammation, overhydration and elevated cardiac biomarkers are related to outcome in haemodialysis (HD) patients. Here, we explored the relationship between the body composition (BC), inflammation and cardiac biomarker concentrations in HD patients longitudinally. METHODS: A total of 44 HD patients were followed for 6 months. BC was assessed by multifrequency bioimpedance (BIA). Serum concentrations of cardiac troponin T (cTnT), high-sensitive C-reactive protein (hsCRP), brain natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) were assessed at 2 monthly intervals. The longitudinal data analysis was conducted with a marginal model. RESULTS: During the follow-up, the parameters describing the BC were highly predictive of both BNP and NT-proBNP and independent of gender, time, hsCRP and cTnT concentrations. The intracellular water (ICW)/body weight (BW) ratio (reflecting malnutrition) exerted a negative effect, whereas the extracellular water (ECW)/BW ratio (reflecting overhydration) had a positive effect on BNP and NT-proBNP concentrations. HsCRP and cTnT concentrations were significantly associated with each other. Furthermore, NT-proBNP concentrations were predictive of cTnT and hsCRP concentrations. CONCLUSIONS: In the present study, we find a significant relation between BIA-derived BC parameters and natriuretic peptide concentrations. This relationship was independent of the cardiac history of the patient and suggests that the natriuretic peptide levels are to some degree modifiable by changing a patient's fluid distribution. Moreover, cTnT, BNP, NT-proBNP and hsCRP were significantly related, showing a complex relation between overhydration, malnutrition, inflammation and cardiac biomarkers in dialysis patients