A sensitive cardiac troponin T assay in stable coronary artery disease.
ABSTRACT: BACKGROUND:In most patients with stable coronary artery disease, plasma cardiac troponin T levels are below the limit of detection for the conventional assay. The distribution and determinants of very low circulating troponin T levels, as well as their association with cardiovascular events, in such patients are unknown. METHODS:We used a new, high-sensitivity assay to determine the concentration of cardiac troponin T in plasma samples from 3679 patients with stable coronary artery disease and preserved left ventricular function. Results of the assay were analyzed in relation to the incidence of cardiovascular events during a median follow-up period of 5.2 years. RESULTS:With the highly sensitive assay, concentrations of cardiac troponin T were at or above the limit of detection (0.001 microg per liter) in 3593 patients (97.7%) and at or above the 99th percentile for apparently healthy subjects (0.0133 microg per liter) in 407 patients (11.1%). After adjustment for other independent prognostic indicators, there was a strong and graded increase in the cumulative incidence of cardiovascular death (adjusted hazard ratio per unit increase in the natural logarithm of the troponin T level, 2.09; 95% confidence interval [CI], 1.60 to 2.74; P<0.001) and of heart failure (adjusted hazard ratio, 2.20; 95% CI, 1.66 to 2.90; P<0.001) in this study group. Increased risk associated with higher levels of troponin T was evident well below the limit of detection of conventional cardiac troponin T assays and below the 99th percentile of values in a healthy population. There was no association between troponin T levels as measured with the highly sensitive assay and the incidence of myocardial infarction (adjusted hazard ratio, 1.16; 95% CI, 0.97 to 1.40; P=0.11). CONCLUSIONS:After adjustment for other independent prognostic indicators, cardiac troponin T concentrations as measured with a highly sensitive assay were significantly associated with the incidence of cardiovascular death and heart failure but not with myocardial infarction in patients with stable coronary artery disease.
Project description:BACKGROUND:High-sensitivity cardiac troponin assays permit use of lower thresholds for the diagnosis of myocardial infarction, but whether this improves clinical outcomes is unknown. We aimed to determine whether the introduction of a high-sensitivity cardiac troponin I (hs-cTnI) assay with a sex-specific 99th centile diagnostic threshold would reduce subsequent myocardial infarction or cardiovascular death in patients with suspected acute coronary syndrome. METHODS:In this stepped-wedge, cluster-randomised controlled trial across ten secondary or tertiary care hospitals in Scotland, we evaluated the implementation of an hs-cTnI assay in consecutive patients who had been admitted to the hospitals' emergency departments with suspected acute coronary syndrome. Patients were eligible for inclusion if they presented with suspected acute coronary syndrome and had paired cardiac troponin measurements from the standard care and trial assays. During a validation phase of 6-12 months, results from the hs-cTnI assay were concealed from the attending clinician, and a contemporary cardiac troponin I (cTnI) assay was used to guide care. Hospitals were randomly allocated to early (n=5 hospitals) or late (n=5 hospitals) implementation, in which the high-sensitivity assay and sex-specific 99th centile diagnostic threshold was introduced immediately after the 6-month validation phase or was deferred for a further 6 months. Patients reclassified by the high-sensitivity assay were defined as those with an increased hs-cTnI concentration in whom cTnI concentrations were below the diagnostic threshold on the contemporary assay. The primary outcome was subsequent myocardial infarction or death from cardiovascular causes at 1 year after initial presentation. Outcomes were compared in patients reclassified by the high-sensitivity assay before and after its implementation by use of an adjusted generalised linear mixed model. This trial is registered with ClinicalTrials.gov, number NCT01852123. FINDINGS:Between June 10, 2013, and March 3, 2016, we enrolled 48?282 consecutive patients (61 [SD 17] years, 47% women) of whom 10?360 (21%) patients had cTnI concentrations greater than those of the 99th centile of the normal range of values, who were identified by the contemporary assay or the high-sensitivity assay. The high-sensitivity assay reclassified 1771 (17%) of 10?360 patients with myocardial injury or infarction who were not identified by the contemporary assay. In those reclassified, subsequent myocardial infarction or cardiovascular death within 1 year occurred in 105 (15%) of 720 patients in the validation phase and 131 (12%) of 1051 patients in the implementation phase (adjusted odds ratio for implementation vs validation phase 1·10, 95% CI 0·75 to 1·61; p=0·620). INTERPRETATION:Use of a high-sensitivity assay prompted reclassification of 1771 (17%) of 10?360 patients with myocardial injury or infarction, but was not associated with a lower subsequent incidence of myocardial infarction or cardiovascular death at 1 year. Our findings question whether the diagnostic threshold for myocardial infarction should be based on the 99th centile derived from a normal reference population. FUNDING:The British Heart Foundation.
Project description:Using high-sensitivity cardiac troponin (hs-cTn) assays with sex-specific 99th percentiles may improve management of patients with suspected acute myocardial infarction (AMI). We investigated the impact of transitioning from a conventional troponin I assay to a high-sensitivity assay with sex-specific thresholds, in patients with suspected acute coronary syndrome admitted to Swedish coronary care units. Based on data from SWEDEHEART registry (females, n?=?4,819/males, n?=?7,670), we compared periods before and after implementation of hs-cTnI assay (Abbott) using sex-specific 99th percentiles. We investigated differences on discharge diagnosis, in-hospital examinations, treatments, and clinical outcome. Upon implementation of the hs-cTnI assay, proportion of patients with troponin levels above diagnostic AMI threshold increased in women and men by 24.3% versus 14.8%, respectively. Similarly, incidence of AMI increased by 11.5% and 9.8%. Diagnostic interventions and treatments increased regardless of sex. However, these associations did not persist following multivariable adjustment, probably due to the effect of temporal management trends during the observation period. Overall, no risk reduction on major adverse cardiovascular events was observed (HR: 0.91 [95% CI 0.80-1.03], P?=?0.126). The implementation of hs-cTnI assay together with sex-specific 99th percentiles was associated with an increase in incidence of AMI regardless of sex, but had no major impact on clinical management and prognosis.
Project description:To determine whether copeptin-us can rule out diagnosis of non-ST-segment elevation myocardial infarction (NSTEMI) without prolonged monitoring and serial blood sampling in patients with high-sensitive cardiac troponin I (hs-cTnI) below the 99th centile at presentation to the emergency department (ED) [corrected].Prospective, non-randomised, individual blinded diagnostic accuracy study.Two EDs of a rural region of France.Patients with chest pain suspected of NSTEMI with onset within the last 12 h were considered for enrollment.Serial clinical, electrographical and biochemical investigations were performed at admission and after 2, 4, 6 and 12 h. Hs-cTnI was measured using an assay with Dimension VISTA, Siemens [corrected]. Copeptin was measured by the BRAHMS copeptin-us assay on the KRYPTOR Compact Plus system. The follow-up period was 90 days.Copeptin, troponin, myoglobin and creatine kinase values. Clinical and paraclinical events. The final diagnosis was adjudicated blinded to copeptin result.During 12 months, 102 patients were analysed. Final diagnosis was NSTEMI for 7.8% (n=8), unstable angina for 3.9% (n=4), cardiac but non-coronary artery disease for 8.8% (n=9), non-cardiac chest pain for 52% (n=53) and unknown for 27.5% (n=28). There was no statistical difference for copeptin values between patients with NSTEMI and others (respectively 5.5 pmol/L IQR (3.1-7.9) and 6.5 pmol/L IQR (3.9-12.1), p=0.49). Only one patient with NSTEMI had a copeptin value above the cut-off of 95th centile at admission.In this study, copeptin does not add a diagnostic value at admission to ED for patients with suspected acute coronary syndrome without ST-segment elevation and with hs-cTnI below the 99th centile [corrected].Clinicaltrials.gov identifier: NCT01334645.
Project description:BACKGROUND:Major disparities between women and men in the diagnosis, management, and outcomes of acute coronary syndrome are well recognized. OBJECTIVES:The aim of this study was to evaluate the impact of implementing a high-sensitivity cardiac troponin I assay with sex-specific diagnostic thresholds for myocardial infarction in women and men with suspected acute coronary syndrome. METHODS:Consecutive patients with suspected acute coronary syndrome were enrolled in a stepped-wedge, cluster-randomized controlled trial across 10 hospitals. Myocardial injury was defined as high-sensitivity cardiac troponin I concentration >99th centile of 16 ng/l in women and 34 ng/l in men. The primary outcome was recurrent myocardial infarction or cardiovascular death at 1 year. RESULTS:A total of 48,282 patients (47% women) were included. Use of the high-sensitivity cardiac troponin I assay with sex-specific thresholds increased myocardial injury in women by 42% and in men by 6%. Following implementation, women with myocardial injury remained less likely than men to undergo coronary revascularization (15% vs. 34%) and to receive dual antiplatelet (26% vs. 43%), statin (16% vs. 26%), or other preventive therapies (p < 0.001 for all). The primary outcome occurred in 18% (369 of 2,072) and 17% (488 of 2,919) of women with myocardial injury before and after implementation, respectively (adjusted hazard ratio: 1.11; 95% confidence interval: 0.92 to 1.33), compared with 18% (370 of 2,044) and 15% (513 of 3,325) of men (adjusted hazard ratio: 0.85; 95% confidence interval: 0.71 to 1.01). CONCLUSIONS:Use of sex-specific thresholds identified 5 times more additional women than men with myocardial injury. Despite this increase, women received approximately one-half the number of treatments for coronary artery disease as men, and outcomes were not improved. (High-Sensitivity Troponin in the Evaluation of Patients With Acute Coronary Syndrome [High-STEACS]; NCT01852123).
Project description:Cardiac troponin concentrations are used to identify patients who would benefit from urgent revascularization for acute coronary syndromes. We hypothesized that they might be used in patients with stable ischemic heart disease to identify those at high risk for cardiovascular events who might also benefit from prompt coronary revascularization.We measured the cardiac troponin T concentration at baseline with a high-sensitivity assay in 2285 patients who had both type 2 diabetes and stable ischemic heart disease and were enrolled in the Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes trial. We tested for an association between the troponin T concentration and a composite end point of death from cardiovascular causes, myocardial infarction, or stroke; we then evaluated whether random assignment to prompt revascularization reduced the rate of the composite end point in patients with an abnormal troponin T concentration (?14 ng per liter) as compared with those with a normal troponin T concentration (<14 ng per liter).Of the 2285 patients, 2277 (99.6%) had detectable (?3 ng per liter) troponin T concentrations and 897 (39.3%) had abnormal troponin T concentrations at baseline. The 5-year rate of the composite end point was 27.1% among the patients who had had abnormal troponin T concentrations at baseline, as compared with 12.9% among those who had had normal baseline troponin T concentrations. In models that were adjusted for cardiovascular risk factors, severity of diabetes, electrocardiographic abnormalities, and coronary anatomy, the hazard ratio for the composite end point among patients with abnormal troponin T concentrations was 1.85 (95% confidence interval [CI], 1.48 to 2.32; P<0.001). Among patients with abnormal troponin T concentrations, random assignment to prompt revascularization, as compared with medical therapy alone, did not result in a significant reduction in the rate of the composite end point (hazard ratio, 0.96; 95% CI, 0.74 to 1.25).The cardiac troponin T concentration was an independent predictor of death from cardiovascular causes, myocardial infarction, or stroke in patients who had both type 2 diabetes and stable ischemic heart disease. An abnormal troponin T value of 14 ng per liter or higher did not identify a subgroup of patients who benefited from random assignment to prompt coronary revascularization. (Funded by the National Institutes of Health and Roche Diagnostics; BARI 2D ClinicalTrials.gov number, NCT00006305.).
Project description:BACKGROUND:The meaning of high-sensitivity troponin I (hsTnI) concentrations in patients without acute myocardial infarction (MI) requires clarity. We hypothesized that among patients referred for diagnostic coronary angiography without acute MI, hsTnI concentrations would correlate with prevalent coronary artery disease (CAD) and predict incident cardiovascular events and mortality. METHODS AND RESULTS:We measured hsTnI using a single-molecule counting assay (99th percentile, 6 ng/L) in samples from 991 patients obtained at the time of angiography. Concentrations of hsTnI were assessed relative to the severity of CAD and prognosis during mean follow-up of 3.7 years. Median hsTnI concentration was 4.19 ng/L; 38% of patients had hsTnI concentrations ?99th percentile. Across increasing hsTnI quartiles, patients had higher prevalence of angiographic CAD; in multivariate models, hsTnI ?99th percentile independently predicted obstructive CAD (odds ratio: 2.57; P<0.001) and incident MI (hazard ratio [HR]: 2.68; P<0.001), cardiovascular death (HR: 2.29; P=0.001), and all-cause death (HR: 1.84; P=0.004). In those with >70% coronary stenosis, hsTnI ?99th percentile independently predicted incident MI (HR: 1.87; P=0.01), cardiovascular mortality (HR: 2.74; P=0.001), and the composite end point of MI and all-cause death (HR: 2.06; P<0.001). In participants with coronary stenosis <70%, hsTnI ?99th percentile even more strongly predicted incident MI (HR: 8.41; P<0.001), cardiovascular mortality (HR: 3.60; P=0.03), and the composite end point of MI and all-cause death (HR: 3.62; P<0.001). CONCLUSIONS:In a large prospective cohort of patients who were free of prevalent MI and undergoing diagnostic coronary angiography, hsTnI concentrations were associated with higher prevalence of CAD and predicted incident MI, cardiovascular death, and all-cause death. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT00842868.
Project description:For evaluation of patients with chest pain and suspected acute coronary syndrome (ACS), consensus guidelines recommend use of a cardiac troponin cut point that corresponds to the 99 th percentile of a healthy population. Most conventional troponin methods lack sufficient precision at this low level.In a cross-sectional study, 377 patients (mean age 53.7 years, 64.2% male) with chest pain and low to intermediate likelihood for ACS were enrolled in the emergency department. Blood was tested with a precommercial high-sensitivity troponin T assay (hsTnT) and compared with a conventional cardiac troponin T method. Patients underwent a 64-slice coronary computed tomography coronary angiogram at the time of phlebotomy, on average 4 hours from initial presentation. Among patients with acute chest pain, 37 (9.8%) had an ACS. Using the 99th percentile cut point for a healthy population (13 pg/mL), hsTnT had 62% sensitivity, 89% specificity, 38% positive predictive value, and 96% negative predictive value for ACS. Compared with the cardiac troponin T method, hsTnT detected 27% more ACS cases (P=.001), and an hsTnT above the 99 th percentile strongly predicted ACS (odds ratio 9.0, 95% confidence interval 3.9 to 20.9, P<0.001). Independent of ACS diagnosis, computed tomography angiography demonstrated that concentrations of hsTnT were determined by numerous factors, including the presence and severity of coronary artery disease, left ventricular mass, left ventricular ejection fraction, and regional left ventricular dysfunction.Among low- to intermediate-risk patients with chest pain, hsTnT provides good sensitivity and specificity for ACS. Elevation of hsTnT identifies patients with myocardial injury and significant structural heart disease, irrespective of the diagnosis of ACS.
Project description:BACKGROUND:The objective of this study was to investigate the predictive power of a high-sensitivity cardiac troponin I (hs-cTnI) assay for cardiovascular events and mortality in a large population of older community dwellers. METHODS:Blood was collected from 5764 individuals (age 66-98 years) during the period of 2002-2006 and the outcome as to all-cause death and incidence of cardiovascular disease (CVD) and coronary heart disease (CHD) followed up to 10 years. hs-cTnI (Abbott) was measured in serum to assess the association of this marker with CVD, CHD and death, and finally, to compare the results with conventional risk factors by multivariable statistical analysis. RESULTS:The median (interquartile range) concentrations of hs-cTnI were 8.4 ng/L (5.6-14.2 ng/L) and 5.3 ng/L (3.8-8.1 ng/L) in men (2416) and women (3275), respectively, and the concentrations increased linearly with age. Outcomes as to all-cause death and incidence of CVD and CHD were significantly associated with increasing concentrations of hs-cTnI beginning well below the 99th percentile concentrations. The associations with outcome remained after adjustments for conventional risk factors and were similar in men and women. CONCLUSIONS:Our findings suggest that hs-cTnI reflects the status of the myocardium even in seemingly healthy individuals and that the measurements of hs-cTnI may be useful for primary prediction of heart disease; this should form the basis for future prospective clinical trials for determining whether measuring hs-cTnI can be used in the prevention of CVD/CHD.
Project description:BACKGROUND:High-sensitivity cardiac troponin testing may improve the risk stratification and diagnosis of myocardial infarction, but concentrations can be challenging to interpret in patients with renal impairment, and the effectiveness of testing in this group is uncertain. METHODS:In a prospective multicenter study of consecutive patients with suspected acute coronary syndrome, we evaluated the performance of high-sensitivity cardiac troponin I in those with and without renal impairment (estimated glomerular filtration rate <60mL/min/1.73m2). The negative predictive value and sensitivity of troponin concentrations below the risk stratification threshold (5 ng/L) at presentation were reported for a primary outcome of index type 1 myocardial infarction, or type 1 myocardial infarction or cardiac death at 30 days. The positive predictive value and specificity at the 99th centile diagnostic threshold (16 ng/L in women, 34 ng/L in men) was determined for index type 1 myocardial infarction. Subsequent type 1 myocardial infarction and cardiac death were reported at 1 year. RESULTS:Of 4726 patients identified, 904 (19%) had renal impairment. Troponin concentrations <5 ng/L at presentation identified 17% of patients with renal impairment as low risk for the primary outcome (negative predictive value, 98.4%; 95% confidence interval [CI], 96.0%-99.7%; sensitivity 98.9%; 95%CI, 97.5%-99.9%), in comparison with 56% without renal impairment (P<0.001) with similar performance (negative predictive value, 99.7%; 95% CI, 99.4%-99.9%; sensitivity 98.4%; 95% CI, 97.2%-99.4%). The positive predictive value and specificity at the 99th centile were lower in patients with renal impairment at 50.0% (95% CI, 45.2%-54.8%) and 70.9% (95% CI, 67.5%-74.2%), respectively, in comparison with 62.4% (95% CI, 58.8%-65.9%) and 92.1% (95% CI, 91.2%-93.0%) in those without. At 1 year, patients with troponin concentrations >99th centile and renal impairment were at greater risk of subsequent myocardial infarction or cardiac death than those with normal renal function (24% versus 10%; adjusted hazard ratio, 2.19; 95% CI, 1.54-3.11). CONCLUSIONS:In suspected acute coronary syndrome, high-sensitivity cardiac troponin identified fewer patients with renal impairment as low risk and more as high risk, but with lower specificity for type 1 myocardial infarction. Irrespective of diagnosis, patients with renal impairment and elevated cardiac troponin concentrations had a 2-fold greater risk of a major cardiac event than those with normal renal function, and should be considered for further investigation and treatment. CLINICAL TRIAL REGISTRATION:URL: https://www.clinicaltrials.gov. Unique identifier: NCT01852123.
Project description:To assess the relation between troponin concentration, assay precision, and clinical outcomes in patients with suspected acute coronary syndrome.Cohort study.Tertiary centre in Scotland.2092 consecutive patients admitted with suspected acute coronary syndrome were stratified with a sensitive troponin I assay into three groups (<0.012, 0.012-0.049, and ?0.050 µg/L) based on the 99th centile for troponin concentration (0.012 µg/L; coefficient of variation 20.8%) and the diagnostic threshold (0.050 µg/L; 7.2%).One year survival without events (recurrent myocardial infarction, death) in patients grouped by troponin concentration.Troponin I concentrations were <0.012 µg/L in 988 patients (47%), 0.012-0.049 µg/L in 352 patients (17%), and ?0.050 µg/L in 752 patients (36%). Adoption of the 99th centile would increase the number of people receiving a diagnosis of myocardial infarction from 752 to 1104: a relative increase of 47%. At one year, patients with troponin concentrations of 0.012-0.049 µg/L were more likely to be dead or readmitted with recurrent myocardial infarction than those with troponin concentrations <0.012 µg/L (13% v 3%, P<0.001; odds ratio 4.7, 95% confidence interval 2.9 to 7.9). Compared with troponin ?0.050 µg/L, patients with troponin 0.012-0.049 µg/L had a higher risk profile but were less likely to have a diagnosis of, or be investigated and treated for, acute coronary syndrome.Lowering the diagnostic threshold to the 99th centile and accepting greater assay imprecision would identify more patients with acute coronary syndrome at risk of recurrent myocardial infarction and death but would increase the diagnosis of myocardial infarction by 47%. It remains to be established whether reclassification of these patients and treatment for myocardial infarction would improve outcome.