Optimal Cutoff Levels of More Sensitive Cardiac Troponin Assays for the Early Diagnosis of Myocardial Infarction in Patients With Renal Dysfunction.

BACKGROUND: It is unknown whether more sensitive cardiac troponin (cTn) assays maintain their clinical utility in patients with renal dysfunction. Moreover, their optimal cutoff levels in this vulnerable patient population have not previously been defined. METHODS AND RESULTS: In this multicenter study, we examined the clinical utility of 7 more sensitive cTn assays (3 sensitive and 4 high-sensitivity cTn assays) in patients presenting with symptoms suggestive of acute myocardial infarction. Among 2813 unselected patients, 447 (16%) had renal dysfunction (defined as Modification of Diet in Renal Disease-estimated glomerular filtration rate <60 mL·min(-1)·1.73 m(-2)). The final diagnosis was centrally adjudicated by 2 independent cardiologists using all available information, including coronary angiography and serial levels of high-sensitivity cTnT. Acute myocardial infarction was the final diagnosis in 36% of all patients with renal dysfunction. Among patients with renal dysfunction and elevated baseline cTn levels (≥99th percentile), acute myocardial infarction was the most common diagnosis for all assays (range, 45%-80%). In patients with renal dysfunction, diagnostic accuracy at presentation, quantified by the area under the receiver-operator characteristic curve, was 0.87 to 0.89 with no significant differences between the 7 more sensitive cTn assays and further increased to 0.91 to 0.95 at 3 hours. Overall, the area under the receiver-operator characteristic curve in patients with renal dysfunction was only slightly lower than in patients with normal renal function. The optimal receiver-operator characteristic curve-derived cTn cutoff levels in patients with renal dysfunction were significantly higher compared with those in patients with normal renal function (factor, 1.9-3.4). CONCLUSIONS: More sensitive cTn assays maintain high diagnostic accuracy in patients with renal dysfunction. To ensure the best possible clinical use, assay-specific optimal cutoff levels, which are higher in patients with renal dysfunction, should be considered. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00470587.

Assessment of microRNAs in patients with unstable angina pectoris.

AIMS: While cardiac troponin measurements have significantly improved the early diagnosis of myocardial infarction, the timely biomarker-based diagnosis of unstable angina pectoris (UAP) remains a major unmet clinical challenge. The aim of this study was to assess levels of circulating microRNAs (miRNAs) as possible novel biomarkers in patients with UAP. METHODS AND RESULTS: A three-phase approach was conducted, comprising (i) profiling of miRNAs in patients with UAP and controls groups; (ii) replication of significant miRNAs in an independent patient cohort, (iii) validation of a multi-miRNAs panel in a third cohort. Out of 25 miRNAs selected for replication, 8 miRNAs remained significantly associated with UAP. In a validation phase, a miRNA panel including miR-132, miR-150, and miR-186 showed the highest discriminatory power [area under the receiver-operating-characteristic curve (AUC): 0.91; CI: 0.84-0.98]. CONCLUSION: Using a profiling-replication-validation model, we identified eight miRNAs, which may facilitate the diagnosis of UAP.

Risk stratification in patients with acute chest pain using three high-sensitivity cardiac troponin assays.

AIMS: Several high-sensitivity cardiac troponin (hs-cTn) assays have recently been developed. It is unknown which hs-cTn provides the most accurate prognostic information and to what extent early changes in hs-cTn predict mortality. METHODS AND RESULTS: In a prospective, international multicentre study, cTn was simultaneously measured with three novel [high-sensitivity cardiac Troponin T (hs-cTnT), Roche Diagnostics; hs-cTnI, Beckman-Coulter; hs-cTnI, Siemens] and a conventional assay (cTnT, Roche Diagnostics) in a blinded fashion in 1117 unselected patients with acute chest pain. Patients were followed up 2 years regarding mortality. Eighty-two (7.3%) patients died during the follow-up. The 2-year prognostic accuracy of hs-cTn was most accurate for hs-cTnT [area under the receivers operating characteristic curve (AUC) 0.78 (95% CI: 0.73-0.83) and outperformed both hs-cTnI (Beckman-Coulter, 0.71 (95% CI: 0.65-0.77; P = 0.001 for comparison), hs-cTnI (Siemens) 0.70 (95% CI: 0.64-0.76; P < 0.001 for comparison)] and cTnT 0.67 (95% CI: 0.61-0.74; P < 0.001 for comparison). Absolute changes of hs-cTnT were more accurate than relative changes in predicting mortality, but inferior to presentation values of hs-cTnT. Combining changes of hs-cTnT within the first 6 h with their presentation values did not further improve prognostic accuracy. Similar results were obtained for both hs-cTnI assays regarding the incremental value of changes. Hs-cTn concentrations remained predictors of death in clinically challenging subgroups such as patients with pre-existing coronary artery disease, impaired renal function, and patients older than 75 years. CONCLUSION: High-sensitivity cardiac Troponin T is more accurate than hs-cTnI in the prediction of long-term mortality. Changes of hs-cTn do not seem to further improve risk stratification beyond initial presentation values.

Direct comparison of high-sensitivity-cardiac troponin I vs. T for the early diagnosis of acute myocardial infarction.

AIM: It is unknown whether cardiac troponin (cTn) I or cTnT is the preferred biomarker in the early diagnosis of acute myocardial infarction without ST segment elevation (NSTEMI). METHODS AND RESULTS: In a prospective multicentre study, we measured cTnI and cTnT using clinically available high-sensitivity assays (hs-cTnI Abbott and hs-cTnT Roche) and compared their diagnostic and prognostic accuracies in consecutive patients presenting to the emergency department with acute chest pain. The final diagnosis was adjudicated by two independent cardiologists using all information pertaining to the individual patient. The mean follow-up was 24 months. Among 2226 consecutive patients, 18% had an adjudicated final diagnosis of NSTEMI. Diagnostic accuracy at presentation as quantified by the area under the receiver-operating-characteristics curve (AUC) for NSTEMI was very high and similar for hs-cTnI [AUC: 0.93, 95% confidence interval (CI) 0.92-0.94] and hs-cTnT (0.94, 95% CI: 0.92-0.94) P = 0.62. In early presenters (<3 h since chest pain onset) hs-cTnI showed a higher diagnostic accuracy (AUC: 0.92, 95% CI: 0.89-0.94) when compared with hs-cTnT AUC (0.89, 95% CI: 0.86-0.91) (P = 0.019), while hs-cTnT was superior in late presenters [AUC hs-cTnT 0.96 (95% CI: 0.94-0.96)  vs. hs-cTnI 0.94 (95% CI: 0.93-0.95); P = 0.007]. The prognostic accuracy for all-cause mortality, quantified by AUC, was significantly higher for hs-cTnT (AUC: 0.80; 95% CI: 0.78-0.82) when compared with hs-cTnI (AUC: 0.75; 95% CI: 0.73-0.77; P < 0.001). CONCLUSION: Both hs-cTnI and hs-cTnT provided high diagnostic and prognostic accuracy. The direct comparison revealed small but potentially important differences that might help to further improve the clinical use of hs-cTn.

High-sensitivity cardiac troponin in the distinction of acute myocardial infarction from acute cardiac noncoronary artery disease.

BACKGROUND: We hypothesized that high-sensitivity cardiac troponin (hs-cTn) and its early change are useful in distinguishing acute myocardial infarction (AMI) from acute cardiac noncoronary artery disease. METHODS AND RESULTS: In a prospective, international multicenter study, hs-cTn was measured with 3 assays (hs-cTnT, Roche Diagnostics; hs-cTnI, Beckman-Coulter; hs-cTnI Siemens) in a blinded fashion at presentation and serially thereafter in 887 unselected patients with acute chest pain. Accuracy of the combination of presentation values with serial changes was compared against a final diagnosis adjudicated by 2 independent cardiologists. AMI was the adjudicated final diagnosis in 127 patients (15%); cardiac noncoronary artery disease, in 124 (14%). Patients with AMI had higher median presentation values of hs-cTnT (0.113 µg/L [interquartile range, 0.049-0.246 µg/L] versus 0.012 µg/L [interquartile range, 0.006-0.034 µg/L]; P<0.001) and higher absolute changes in hs-cTnT in the first hour (0.019 µg/L [interquartile range, 0.007-0.067 µg/L] versus 0.001 µg/L [interquartile range, 0-0.003 µg/L]; P<0.001) than patients with cardiac noncoronary artery disease. Similar findings were obtained with the hs-cTnI assays. Adding changes of hs-cTn in the first hour to its presentation value yielded a diagnostic accuracy for AMI as quantified by the area under the receiver-operating characteristics curve of 0.94 for hs-cTnT (0.92 for both hs-cTnI assays). Algorithms using ST-elevation, presentation values, and changes in hs-cTn in the first hour accurately separated patients with AMI and those with cardiac noncoronary artery disease. These findings were confirmed when the final diagnosis was readjudicated with the use of hs-cTnT values and validated in an independent validation cohort. CONCLUSION: The combined use of hs-cTn at presentation and its early absolute change excellently discriminates between patients with AMI and those with cardiac noncoronary artery disease. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00470587.

Risk stratification in patients with unstable angina using absolute serial changes of 3 high-sensitive troponin assays.

BACKGROUND: It is unknown whether unstable angina (UA) results in previously nondetectable low-level myocardial necrosis. We compared the pattern of myocardial necrosis between patients with UA, acute myocardial infarction (AMI), and noncardiac chest pain (NCCP) using 3 high-sensitive cardiac troponin (hs-cTn) assays. METHODS: In a multicenter study, we enrolled 842 unselected patients with acute chest pain in the emergency department. Roche hs-cTnT, Beckman Coulter hs-cTnI, and Siemens hs-cTnI were determined in a blinded fashion at presentation and after 1, 2, 3, and 6 hours. The final diagnosis was adjudicated by 2 independent cardiologists. RESULTS: A change in hs-cTn of ≥2 ng/L within the first hour after presentation as assessed with Roche hs-cTnT, Beckman Coulter hs-cTnI, and Siemens hs-cTnI was observed in 26%, 31%, and 32% of patients with UA (n = 115) compared with 91%, 92%, and 96% in patients with AMI (n = 120) and 12%, 23%, and 16% in patients with NCCP (n = 415; P < .001 for all comparisons between UA and AMI, P > .05 for all comparisons between UA and NCCP). In patients with UA, such a 1-hour change in hs-cTn of ≥2 ng/L was associated with an increased risk of death or AMI during the 30-day follow-up (P = .003, .03, .03) and 2-year follow-up (P < .001, .002, and .006). CONCLUSIONS: In marked contrast to patients with AMI, most patients with UA do not exhibit relevant hs-cTn changes. The minority of UA with hs-cTn changes, however, has a significantly worse short- and long-term outcome.

Comparison of the performances of cardiac troponins, including sensitive assays, and copeptin in the diagnostic of acute myocardial infarction and long-term prognosis between women and men.

BACKGROUND: Concerns have been raised about possible gender disparities in cardiac investigations and/or outcome. This study sought to examine and compare the diagnostic and prognostic performance of selected cardiac biomarkers in women versus men. METHODS: In a prospective, multicenter cohort of patients with acute chest pain cardiac troponin T (cTnT) (fourth-generation Roche assay), high-sensitivity cTnT (hs-cTnT), and copeptin were measured at presentation. RESULTS: Of 1,247 patients, 420 were women and 827 were men. Although the rate of acute myocardial infarction was similar in women (14.5%) and men (16.6%, P = .351), women more frequently had cardiac but noncoronary causes of chest pain (17.4% vs 10.8%, P = .001) and less frequently had unstable angina (8.8% vs 16.6%, P = .002) than men. Diagnostic accuracy as quantified by the area under the receiver operating characteristic curve (AUC) for acute myocardial infarction in women was 0.90 (95% CI 0.84-0.95) for cTnT, which was lower than the AUC for hs-cTnT alone (0.94, 95% CI [0.91-0.98]), the combination of cTnT with copeptin (0.96, 95% CI [0.94-0.98]) or the combination of hs-cTnT with copeptin (0.96, 95% CI [0.93-0.98]) (P = .008, P = .006, and P = .002, respectively). Prognostic accuracy as quantified by the AUCs for 1-year mortality was 0.69 (0.56-0.83), 0.86 (0.79-0.93), 0.87 (0.81-0.94), and 0.87 (0.80-0.94), respectively. No relevant gender differences in AUCs were observed. CONCLUSION: The diagnostic and prognostic performance of cTnT, hs-cTnT, and copeptin is as good in women as in men. High-sensitivity cTnT and the combination of cTnT and copeptin outperform cTnT alone, both in women and men.

Uric acid for diagnosis and risk stratification in suspected myocardial infarction.

BACKGROUND: Hypoxia precedes cardiomyocyte necrosis in acute myocardial infarction (AMI). We therefore hypothesized that uric acid - as a marker of oxidative stress and hypoxia - might be useful in the early diagnosis and risk stratification of patients with suspected AMI. MATERIALS AND METHODS: In this prospective observational study, uric acid was measured at presentation in 892 consecutive patients presenting to the emergency department with suspected AMI. The final diagnosis was adjudicated by two independent cardiologists. Patients were followed 24 months regarding mortality. Primary outcome was the diagnosis of AMI, secondary outcome was short- and long-term mortality. RESULTS: Uric acid at presentation was higher in patients with AMI than in patients without (372 µM vs. 336 µM; P < 0·001). The diagnostic accuracy of uric acid for AMI as quantified by the area under the receiver operating characteristic curve (AUC) was 0·60 (95%Cl 0·56-0·65). When added to cardiac troponin T (cTnT), uric acid significantly increased the AUC of cTnT from 0·89 (95%Cl 0·85-0·93) to 0·92 (95%Cl 0·89-0·95, P = 0·020 for comparison). Cumulative 24-month mortality rates were 2·2% in the first, 5·4% in the second and the third and 15·6% in the fourth quartile of uric acid (P < 0·001 for log-rank). Uric acid predicted 24-month mortality independently. Adding uric acid to TIMI and GRACE risk score improved their prognostic accuracy as shown by an integrated discrimination improvement of 0·04 (P = 0·007) respective 0·02 (P = 0·021). CONCLUSIONS: Uric acid, an inexpensive widely available biomarker, improves both the early diagnosis and risk stratification of patients with suspected AMI.

High-sensitive troponin T measurements: what do we gain and what are the challenges?

Cardiac troponin (cTn) I and T are structural proteins unique to the heart. Detection of cTn in peripheral blood indicates cardiomyocyte damage. As acute myocardial infarction (AMI) is the most important cause of cardiomyocyte damage, cTns have become an integral part in the diagnosis of AMI. For this indication, cTns are superior to all other biomarkers and therefore are the preferred marker for the diagnosis of AMI. However, cTn indicates and provides an estimate of cardiomyocyte damage irrespective of its cause. The major limitation of contemporary cTn assays is that they are often not elevated during the initial hours of AMI. Recent advances in assay technology have led to more sensitive and precise cTn assays that will have a profound impact on clinical practice. High-sensitive cTn (hs-cTn) assays have two differentiating features from contemporary cTn assays: (i) detection of cTn in a majority of healthy persons and (ii) precise definition of what is 'normal' (=the 99th percentile). Recent multicentre studies have shown that hs-cTn assays improve the early diagnosis of patients with suspected AMI, particularly the early rule-out. To achieve best clinical use, cTn has to be interpreted as a quantitative variable. Rising and/or falling levels differentiate acute from chronic cardiomyocyte damage. The terms 'troponin-positive' and 'troponin negative' should therefore be avoided. 'Detectable' levels will become the norm and will have to be differentiated from 'elevated' levels. The differential diagnosis of a small amount of cardiomyocyte damage and therefore minor elevations of cTn is broad and includes acute and chronic cardiac disorders. The differential diagnosis of larger amount of injury and therefore more substantial elevations of cTn is largely restricted to AMI, myocarditis, and a rare patient with tako-tsubo cardiomyopathy.

Early diagnosis of acute myocardial infarction in patients with pre-existing coronary artery disease using more sensitive cardiac troponin assays.

AIMS: We sought to examine the diagnostic and prognostic utility of sensitive cardiac troponin (cTn) assays in patients with pre-existing coronary artery disease (CAD). METHODS AND RESULTS: We conducted a multicentre study to examine the diagnostic accuracy of one high-sensitive and two sensitive cTn assays in 1098 consecutive patients presenting with symptoms suggestive of acute myocardial infarction (AMI), of whom 401 (37%) had pre-existing CAD. Measurements of Roche high-sensitive cTnT (hs-cTnT), Siemens cTnI-Ultra, Abbott-Architect cTnI and the standard assay (Roche cTnT) were performed in a blinded fashion. The final diagnosis was adjudicated by two independent cardiologists. Acute myocardial infarction was the final diagnosis in 19% of CAD patients. Among patients with diagnoses other than AMI, baseline cTn levels were elevated above the 99th percentile with Roche hs-cTnT in 40%, with Siemens TnI-Ultra in 15%, and Abbott-Architect cTnI in 13% of them. In patients with pre-existing CAD, the diagnostic accuracy at presentation, quantified by the area under the receiver operator characteristic curve (AUC), was significantly greater for the sensitive cTn assays compared with the standard assay (AUC for Roche hs-cTnT, 0.92; Siemens cTnI-Ultra, 0.94; and Abbott-Architect cTnI, 0.93 vs. AUC for the standard assay, 0.87; P < 0.01 for all comparisons). Elevated levels of cTn measured with the sensitive assays predicted mortality irrespective of pre-existing CAD, age, sex, and cardiovascular risk factors. CONCLUSION: Sensitive cTn assays have high-diagnostic accuracy also in CAD patients. Mild elevations are common in non-AMI patients and test-specific optimal cut-off levels tend to be higher in CAD patients than in patients without history of CAD. Sensitive cTn assays also retain prognostic value. (ClinicalTrials.gov number, NCT00470587).

Utility of absolute and relative changes in cardiac troponin concentrations in the early diagnosis of acute myocardial infarction.

BACKGROUND: Current guidelines for the diagnosis of acute myocardial infarction (AMI), among other criteria, also require a rise and/or fall in cardiac troponin (cTn) levels. It is unknown whether absolute or relative changes in cTn have higher diagnostic accuracy and should therefore be preferred. METHODS AND RESULTS: In a prospective, observational, multicenter study, we analyzed the diagnostic accuracy of absolute (Δ) and relative (Δ%) changes in cTn in 836 patients presenting to the emergency department with symptoms suggestive of AMI. Blood samples for the determination of high-sensitive cTn T and cTn I ultra were collected at presentation and after 1 and 2 hours in a blinded fashion. The final diagnosis was adjudicated by 2 independent cardiologists. The area under the receiver operating characteristic curve for diagnosing AMI was significantly higher for 2-hour absolute (Δ) versus 2-hour relative (Δ%) cTn changes (area under the receiver operating characteristic curve [95% confidence interval], high-sensitivity cTn T: 0.95 [0.92 to 0.98] versus 0.76 [0.70 to 0.83], P<0.001; cTn I ultra: 0.95 [0.91 to 0.99] versus 0.72 [0.66 to 0.79], P<0.001). The receiver operating characteristic curve-derived cutoff value for 2-hour absolute (Δ) change was 0.007 µg/L for high-sensitivity cTn T and 0.020 µg/L for cTn I ultra (both cutoff levels are half of the 99th percentile of the respective cTn assay). Absolute changes were superior to relative changes in patients with both low and elevated baseline cTn levels. CONCLUSIONS: Absolute changes of cTn levels have a significantly higher diagnostic accuracy for AMI than relative changes, and seem therefore to be the preferred criteria to distinguish AMI from other causes of cTn elevations. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. UNIQUE IDENTIFIER: NCT00470587.

How safe is the outpatient management of patients with acute chest pain and mildly increased cardiac troponin concentrations?

BACKGROUND: The appropriate management of patients discharged from the emergency department (ED) with increased high-sensitivity cardiac troponin T (hs-cTnT) but normal or borderline-high conventional cardiac troponin concentrations is unknown. METHODS: We investigated 643 consecutive ED patients with acute chest pain who had been discharged for outpatient management after acute myocardial infarction (AMI) had been ruled out by serial measurements of conventional cardiac troponin. hs-cTnT was measured blindly, and we calculated the rates of all-cause mortality (primary endpoint) and subsequent AMI (secondary endpoint) at 30, 90, and 360 days. RESULTS: hs-cTnT concentrations were increased (>14 ng/L) in 114 patients (18%) but <30 ng/L in 95% of these patients. Of those 114 patients, 96 (84%) had an adjudicated noncoronary cause of chest pain. Thirty-day mortality (95% CI) was 0.9% (0.1%-6.1%), 90-day mortality was 2.7% (0.9%-8.1%), and 360-day mortality was 5.2% (2.2%-11.9%) in patients with increased hs-cTnT; respective rates (95% CI) of AMI were 0.0%, 1.9% (0.5%-7.2%), and 7.6% (3.7%-15.3%). Increased hs-cTnT was associated with increased mortality and AMI at 90 days (P = 0.006 and P = 0.081, respectively) and 360 days (P = 0.001 for both). CONCLUSIONS: hs-cTnT is a strong prognosticator of intermediate and long-term mortality and AMI in low-risk patients discharged from the ED after AMI has been ruled out. The relatively low rate of 30-day events may suggest that patients without acute coronary syndrome and small increases in cardiac troponin are in need of further investigations and treatments, but not necessarily immediate hospitalization.

Growth differentiation factor-15 in the early diagnosis and risk stratification of patients with acute chest pain.

BACKGROUND: Growth differentiation factor-15 (GDF-15) is a stress-responsive marker that might aid in the early diagnosis and risk stratification of patients with suspected acute myocardial infarction (AMI). METHODS: In a prospective, international multicenter study, GDF-15, high-sensitivity cardiac troponin T (hs-cTnT), and B-type natriuretic peptide (BNP) were measured in 646 unselected patients presenting to the emergency department with acute chest pain. The final diagnosis was adjudicated by 2 independent cardiologists. The primary prognostic end point was all-cause mortality during a median follow-up of 26 months. RESULTS: AMI was the adjudicated final diagnosis in 115 patients (18%). GDF-15 concentrations at presentation were significantly higher in AMI patients compared to patients with other diagnoses. The diagnostic accuracy of GDF-15 at presentation for the diagnosis of AMI as quantified by the area under the ROC curve (AUC) was lower (AUC 0.69, 95% CI 0.64-0.74) compared to hs-cTnT (AUC 0.96, 95% CI 0.94-0.98, P < 0.001) and BNP (AUC 0.74, 95% CI 0.69-0.80, P = 0.02). A total of 55 deaths occurred during follow-up. GDF-15 predicted all-cause mortality independently of and more accurately than hs-cTnT [AUC 0.85 (95% CI 0.81-0.90) vs 0.77 (95% CI 0.72-0.83), P = 0.002] and BNP (AUC 0.75, 95% CI 0.68-0.82, P = 0.007). Net reclassification improvement was 0.15 (P = 0.01), and the absolute integrated discrimination improvement was 0.07, yielding a relative integrated discrimination improvement of 0.36 (P = 0.07). CONCLUSIONS: GDF-15 predicts all-cause mortality in unselected patients with acute chest pain independently of and more accurately than hs-cTnT and BNP. However, GDF-15 does not seem to help in the early diagnosis of AMI.

Markers of plaque instability in the early diagnosis and risk stratification of acute myocardial infarction.

BACKGROUND: Plaque erosion and plaque rupture occur early in the pathophysiology of acute myocardial infarction (AMI). We hypothesized that markers of plaque instability might be useful in the early diagnosis and risk stratification of AMI. METHODS: In this multicenter study, we examined 4 markers of plaque instability, myeloperoxidase (MPO), myeloid-related protein 8/14 (MRP-8/14), pregnancy-associated plasma protein-A (PAPP-A), and C-reactive protein (CRP) in 398 consecutive patients presenting to the emergency department with acute chest pain and compared them to normal and high-sensitivity cardiac troponin T (cTnT and hs-cTnT). The final diagnosis was adjudicated by 2 independent cardiologists. Primary prognostic end point was death during a median follow-up of 27 months. RESULTS: The adjudicated final diagnosis was AMI in 76 patients (19%). At emergency department presentation, concentrations of all 4 biomarkers of plaque instability were significantly higher in patients with AMI than in patients with other diagnoses. However, their diagnostic accuracy as quantified by the area under the ROC curve (AUC) was low (MPO 0.63, MRP-8/14 0.65, PAPP-A 0.62, CRP 0.59) and inferior to both normal and high-sensitivity cardiac troponin T (cTnT 0.88, hs-cTnT 0.96; P<0.001 for all comparisons). Thirty-nine patients (10%) died during follow-up. Concentrations of MPO, MRP-8/14, and CRP were higher in nonsurvivors than in survivors and predicted all-cause mortality with moderate accuracy. CONCLUSIONS: Biomarkers of plaque instability do not seem helpful in the early diagnosis of AMI but may provide some incremental value in the risk stratification of patients with acute chest pain.

Impact of soluble fms-like tyrosine kinase-1 and placental growth factor serum levels for risk stratification and early diagnosis in patients with suspected acute myocardial infarction.

AIMS: Angiogenic factors play an important role in the development of atherosclerosis and show pronounced changes during acute myocardial infarction (AMI). We analysed the impact of placental growth factor (PlGF) and its endogen opponent, soluble fms-like tyrosine kinase-1 (sFlt-1), on clinical outcome and the early diagnosis of AMI. METHODS AND RESULTS: This multicentre study enrolled patients presenting with symptoms suggestive of AMI. The final diagnosis was adjudicated by two independent physicians. Levels of sFlt-1 and PlGF were compared with results of a standard troponin T and a novel high-sensitive troponin (hsTnT) assay. Of the 763 patients enrolled, 132 were diagnosed with AMI. Multivariable Cox regression analysis demonstrated sFlt-1 >84 ng/L [hazard ratios (HR) 2.6, 95% confidence intervals (CI) 1.2-5.4, P=0.01] and PlGF >20 ng/L (HR 3.6, 95% CI 1.3-10.4, P=0.02) as predictors for mortality during 1-year follow-up, independent from information provided by troponin T and N-terminal pro-B-type natriuretic peptide (NT-proBNP). However, only sFlt-1 persisted as independent predictor for mortality when analysed together with hsTnT and NT-proBNP, and after adjusting for significant clinical parameters. For the diagnosis of AMI, the combination of troponin T and sFlt-1 improved the performance of troponin T alone and led to a negative predictive value of 98.3% already at time of presentation. However, sFlt-1 and PlGF added only limited diagnostic information when used together with hsTnT. CONCLUSION: Only sFlt-1 but not PlGF provides overall independent prognostic information in patients presenting with symptoms suggestive of AMI. After the introduction of hsTnT in clinical routine, sFlt-1 and PlGF can only add limited diagnostic information for the detection or exclusion of AMI. CLINICAL TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov, NCT00470587.

Early diagnosis of acute myocardial infarction in the elderly using more sensitive cardiac troponin assays.

AIMS: To examine the diagnostic accuracy of sensitive cardiac troponin (cTn) assays in elderly patients, since elevated levels with sensitive cTn assays were reported in 20% of elderly patients without acute myocardial infarction (AMI). METHODS AND RESULTS: In this multi-centre study, we included 1098 consecutive patients presenting with symptoms suggestive of AMI, 406 (37%) were >70 years old. Measurement of three investigational sensitive cTn assays [Roche high-sensitive cTnT (hs-cTnT), Siemens cTnI-Ultra, and Abbott-Architect cTnI) and the standard assay (Roche cTnT) was performed in a blinded fashion. The final diagnosis was adjudicated by two independent cardiologists. Acute myocardial infarction was the adjudicated final diagnosis in 24% of elderly patients. Among elderly patients without AMI, baseline cTn levels were elevated above the 99th percentile in 51% with Roche hs-cTnT, in 17% with Siemens TnI-Ultra, and 13% with Abbott-Architect cTnI. The diagnostic accuracy as quantified by the area under the receiver operating characteristic (ROC) curve (AUC) was significantly greater for the sensitive cTn assays compared with the standard assay (AUC for Roche hs-cTnT, 0.94; Siemens cTnI-Ultra, 0.95; and Abbott-Architect cTnI, 0.95 vs. AUC for the standard assay, 0.90; P < 0.05 for comparisons). The best cut-offs for the sensitive cTn-assays determined by the ROC-curve in elderly patients differed clearly from those in younger patients. Furthermore, the prognostic value regarding 90-day mortality varied among the sensitive cTn assays. CONCLUSION: Sensitive cTn assays have high diagnostic accuracy also in the elderly. Mild elevations are common in elderly non-AMI patients, therefore the optimal cut-off levels are substantially higher in elderly as compared with younger patients. Furthermore, sensitive cTn assays yielded different prognostic value.

Incremental value of high-sensitivity cardiac troponin T for risk prediction in patients with suspected acute myocardial infarction.

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 < 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 < 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 >0.014 µg/L improve the prediction of death but not subsequent AMI in unselected patients presenting with acute chest pain.

Endogenous stress response in Tako-Tsubo cardiomyopathy and acute myocardial infarction.

BACKGROUND: As the clinical, electrocardiographic and laboratory presentation of Tako-Tsubo cardiomyopathy (TTC) and acute myocardial infarction (AMI) is similar, both entities are in general only distinguishable by coronary angiography. The purpose of this study was to examine the endogenous stress response at presentation, quantified by the copeptin level, of patients with TTC and patients with AMI, as copeptin may be useful in the non-invasive differentiation between both diseases. METHODS: We compared the endogenous stress response at initial presentation, quantified by the plasma copeptin levels, in 21 consecutive patients finally diagnosed with TTC and 21 patients finally diagnosed with AMI matched for sex and time since chest pain onset. RESULTS: The prevalence of cardiovascular risk factors and initial cardiac troponin T levels were comparable in TTC and AMI. Copeptin levels were significantly lower in patients with TTC when compared to patients with AMI (median 4·8 [interquartile range, IQR 3·5-13·5] pM vs. 25·6 [IQR 12·1-63·9] pM, P = 0·002). The accuracy for diagnosing TTC as quantified by the area under the receiver operating characteristics curve was significantly higher for copeptin than for cardiac troponin T (0·782 vs. 0·549, P = 0·031). The optimal cut-off value for differentiation between TTC and AMI was found at a copeptin level of 7·8 pM (sensitivity 67% at a specificity of 86%, negative predictive value 72%, positive predictive value 82%). CONCLUSIONS: The endogenous stress response, quantified by a novel sensitive biomarker, seems to be different in patients with TTC and AMI. Copeptin levels may be helpful in the non-invasive differentiation between TTC and AMI.

Direct comparison of serial B-type natriuretic peptide and NT-proBNP levels for prediction of short- and long-term outcome in acute decompensated heart failure.

INTRODUCTION: Monitoring treatment efficacy and assessing outcome by serial measurements of natriuretic peptides in acute decompensated heart failure (ADHF) patients may help to improve outcome. METHODS: This was a prospective multi-center study of 171 consecutive patients (mean age 80 73-85 years) presenting to the emergency department with ADHF. Measurement of BNP and NT-proBNP was performed at presentation, 24 hours, 48 hours and at discharge. The primary endpoint was one-year all-cause mortality; secondary endpoints were 30-days all-cause mortality and one-year heart failure (HF) readmission. RESULTS: During one-year follow-up, a total of 60 (35%) patients died. BNP and NT-proBNP levels were higher in non-survivors at all time points (all P < 0.001). In survivors, treatment reduced BNP and NT-proBNP levels by more than 50% (P < 0.001), while in non-survivors treatment did not lower BNP and NT-proBNP levels. The area under the ROC curve (AUC) for the prediction of one-year mortality increased during the course of hospitalization for BNP (AUC presentation: 0.67; AUC 24 h: 0.77; AUC 48 h: 0.78; AUC discharge: 0.78) and NT-proBNP (AUC presentation: 0.67; AUC 24 h: 0.73; AUC 48 h: 0.75; AUC discharge: 0.77). In multivariate analysis, BNP at 24 h (1.02 [1.01-1.04], P = 0.003), 48 h (1.04 [1.02-1.06], P < 0.001) and discharge (1.02 [1.01-1.03], P < 0.001) independently predicted one-year mortality, while only pre-discharge NT-proBNP was predictive (1.07 [1.01-1.13], P = 0.016). Comparable results could be obtained for the secondary endpoint 30-days mortality but not for one-year HF readmissions. CONCLUSIONS: BNP and NT-proBNP reliably predict one-year mortality in patients with ADHF. Prognostic accuracy of both biomarker increases during the course of hospitalization. In survivors BNP levels decline more rapidly than NT-proBNP levels and thus seem to allow earlier assessment of treatment efficacy. Ability to predict one-year HF readmission was poor for BNP and NT-proBNP. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00514384.

Copeptin and risk stratification in patients with acute dyspnea.

INTRODUCTION: The identification of patients at highest risk for adverse outcome who are presenting with acute dyspnea to the emergency department remains a challenge. This study investigates the prognostic value of Copeptin, the C-terminal part of the vasopressin prohormone alone and combined to N-terminal pro B-type natriuretic peptide (NT-proBNP) in patients with acute dyspnea. METHODS: We conducted a prospective, observational cohort study in the emergency department of a university hospital and enrolled 287 patients with acute dyspnea. RESULTS: Copeptin levels were elevated in non-survivors (n = 29) compared to survivors at 30 days (108 pmol/l, interquartile range (IQR) 37 to 197 pmol/l) vs. 18 pmol/l, IQR 7 to 43 pmol/l; P < 0.0001). The areas under the receiver operating characteristic curve (AUC) to predict 30-day mortality were 0.83 (95% confidence interval (CI) 0.76 to 0.90), 0.76 (95% CI 0.67 to 0.84) and 0.63 (95% CI 0.53 to 0.74) for Copeptin, NT-proBNP and BNP, respectively (Copeptin vs. NTproBNP P = 0.21; Copeptin vs. BNP P = 0.002). When adjusted for common cardiovascular risk factors and NT-proBNP, Copeptin was the strongest independent predictor for short-term mortality in all patients (HR 3.88 (1.94 to 7.77); P < 0.001) and especially in patients with acute decompensated heart failure (ADHF) (HR 5.99 (2.55 to 14.07); P < 0.0001). With the inclusion of Copeptin to the adjusted model including NTproBNP, the net reclassification improvement (NRI) was 0.37 (P < 0.001). An additional 30% of those who experienced events were reclassified as high risk, and an additional 26% without events were reclassified as low risk. CONCLUSIONS: Copeptin is a new promising prognostic marker for short-term mortality independently and additive to natriuretic peptide levels in patients with acute dyspnea.