Julia Meissner

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 (&Dgr;) and relative (&Dgr;%) 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 (&Dgr;) versus 2-hour relative (&Dgr;%) 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 (&Dgr;) change was 0.007 &mgr;g/L for high-sensitivity cTn T and 0.020 &mgr;g/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.

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.

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 &mgr;g/L [interquartile range, 0.049–0.246 &mgr;g/L] versus 0.012 &mgr;g/L [interquartile range, 0.006–0.034 &mgr;g/L]; P<0.001) and higher absolute changes in hs-cTnT in the first hour (0.019 &mgr;g/L [interquartile range, 0.007–0.067 &mgr;g/L] versus 0.001 &mgr;g/L [interquartile range, 0–0.003 &mgr;g/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.

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).

Use of Myeloperoxidase for Risk Stratification in Acute Heart Failure

BACKGROUND Myeloperoxidase (MPO) is a biomarker of inflammation and oxidative stress produced by neutrophils, monocytes, and endothelial cells. Concentrations of MPO predict mortality in patients with chronic heart failure. This study sought to investigate the diagnostic accuracy and prognostic value of MPO in patients with acute heart failure (AHF). METHODS We prospectively enrolled 667 patients presenting to the emergency department with dyspnea and observed them for 1 year. MPO and B-type natriuretic peptide (BNP) were measured at presentation. Two independent cardiologists adjudicated final discharge diagnoses. RESULTS MPO concentrations were similar in patients with AHF (n = 377, median 139 pmol/L) and patients with noncardiac causes of dyspnea (n = 290, median 150 pmol/L, P = 0.26). The diagnostic accuracy of MPO for AHF was limited [area under the ROC curve (AUC) 0.53] and inferior to that of BNP (AUC 0.95, P < 0.001). In patients with AHF, MPO concentrations above the lowest tertile (MPO >99 pmol/L) were associated with significantly increased 1-year mortality (hazard ratio 1.58, P = 0.02). The combination of MPO (< or = 99 vs >99 pmol/L) and BNP (median of < or = 847 vs >847 ng/L) improved the prediction of 1-year mortality (hazard ratio 2.80 for both variables increased vs both low, P < 0.001). After adjustment for cardiovascular risk factors in multivariable Cox proportional hazard analysis, increases in MPO contributed significantly toward the prediction of 1-year mortality (hazard ratio 1.51, P = 0.045). CONCLUSIONS MPO is an independent predictor of 1-year mortality in AHF, is additive to BNP, and could be helpful in identifying patients with a favorable prognosis despite increased BNP concentrations.

The GRACE score's performance in predicting in-hospital and 1-year outcome in the era of high-sensitivity cardiac troponin assays and B-type natriuretic peptide

Objective To compare the accuracy of the GRACE score, a strong prognosticator in acute coronary syndrome (ACS) that is calculated using conventional cardiac troponin (cTn) assays, with that calculated with high-sensitivity cTn (hs-cTn) and with the combination of the GRACE score with hs-cTn or B-type natriuretic peptide (BNP). Design Prospective international cohort. Settings University Hospital. Patients Patients enrolled in the Predictors of Acute Coronary Syndromes Evaluation prospective study with proven ACS. Main outcome measured The capacity to predict in-hospital mortality, 1-year mortality and combined death/acute myocardial infarction (AMI) at 1 year. Results 370 patients were enrolled (173 with unstable angina and 197 with AMI). In-hospital mortality was 4.1%; 1-year mortality was 12.5%. The GRACE score was significantly higher in patients who died than in those discharged alive (200 (174–222) vs 125 (98–155); p<0.001), and in those who died than in those who survived for 1 year (151 (133–169) vs 104 (85–125); p<0.001). The area under the curve of the GRACE score was 0.87 regarding in-hospital mortality and 0.88 for 1-year mortality; if calculated with hs-cTn, it was 0.87 and 0.88, respectively (p=NS for all comparisons). The addition of hs-cTn to the GRACE score resulted in no increased value, whereas the addition of BNP tended to improve 1-year mortality prediction (p=0.058). Conclusion The GRACE score is accurate for determining both in-hospital and long-term mortality in patients with ACS in the era of hs-cTn. The addition of hs-cTn or BNP to the GRACE score does not significantly improve risk prediction.

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.

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.

Interleukin family member ST2 and mortality in acute dyspnoea

Abstract.  Socrates T, deFilippi C, Reichlin T, Twerenbold R, Breidhardt T, Noveanu M, Potocki M, Reiter M, Arenja N, Heinisch C, Meissner J, Jaeger C, Christenson R, Mueller C. (Department of Internal Medicine, University Hospital Basel, Basel, Switzerland; University of Maryland, School of Medicine, Baltimore, MD, USA). Interleukin family member ST2 and mortality in acute dyspnoea. J Intern Med 2010; 268: 493–500.

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.