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.

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.

Heart failure therapy-induced early ST2 changes may offer long-term therapy guidance.

BACKGROUND: Biomarkers may help to monitor and tailor treatment in patients with acute heart failure (AHF). METHODS AND RESULTS: Levels of ST2, a novel biomarker integrating hypervolemic cardiac strain and proinflammatory signals, were measured at presentation to the emergency department (ED) and after 48 hours in 207 patients with AHF. Patients were stratified according to their early ST2 response (responders: ST2 decrease ≥25%; nonresponders: ST2 decrease <25%) and beta-blocker, renin-angiotensin-aldosterone system (RAAS) blockade, or diuretic treatment status at hospital discharge. We assessed the utility of ST2 levels and its changes to predict long-term mortality and the interaction between ST2 levels, treatment at discharge, and 1-year mortality. ST2 levels were higher in nonsurvivors than in survivors (median 108 vs 69 ng/mL; P < .01) and decreased significantly during the 1st 48 hours (median decrease 33%). ST2 decrease was less in nonsurvivors compared with survivors (median -25% vs -42%; P < .01). In Cox regression, early ST2 changes independently predicted 1-year mortality (hazard ratio 1.07 for every increase of 10%; P = .02). RAAS blockers at discharge were associated with survival independently from ST2 response, whereas the association of beta-blockers with survival differed markedly according to ST2 response, with beneficial effects restricted to ST2 nonresponders (P interaction = .04). A similar, albeit nonsignificant, trend was observed for diuretics (P interaction = .11). CONCLUSIONS: ED and serial ST2 measurements are independent predictors of 1-year mortality in AHF.

Accelerated diagnostic protocol using high-sensitivity cardiac troponin T in acute chest pain patients.

BACKGROUND: We aimed to evaluate the efficacy and safety of using high-sensitivity cardiac troponin T (hs-cTnT) within an accelerated diagnostic protocol (ADP) in patients presenting with symptoms suggestive of acute myocardial infarction (AMI) for rapid rule-out of AMI. METHODS: In two independent large multicenter studies, levels of hs-cTnT at presentation and at 2 h were combined with the Thrombolysis In Myocardial Infarction (TIMI) risk score and ECG findings. The ADP defined patients with normal levels of hs-cTnT at presentation and 2 h, a TIMI score ≤1, and normal ECG findings as candidates for rapid rule-out of AMI and rapid discharge. Major adverse cardiac events (MACEs) occurring within 30-days were centrally adjudicated by two independent cardiologists. RESULTS: In the derivation cohort, among 1085 consecutive patients 198 patients (18.2%) had a MACE. The ADP classified 374 patients (34.5%) as low-risk. None of these patients had a MACE at 30 days, resulting in a negative predictive value (NPV) of 100% (95% CI, 99.0-100%) and a sensitivity of 100% (95% CI, 98.2%-100%). In the validation cohort, among 1590 consecutive patients 231 patients (14.5%) had a MACE. The ADP classified 641 patients (40.3%) as low-risk. 6 of these patients had a MACE at 30 days, resulting in a NPV of 99.1% (95% CI, 98.0-99.6%) and a sensitivity of 97.4% (95% CI, 94.5-98.8%). CONCLUSIONS: The ADP including hs-cTnT allows early identification 35 to 40% of patients to be at extremely low risk of MACE and therefore ideal candidates for outpatient management.

Sex-specific chest pain characteristics in the early diagnosis of acute myocardial infarction.

IMPORTANCE: Whether sex-specific chest pain characteristics (CPCs) would allow physicians in the emergency department to differentiate women with acute myocardial infarction (AMI) from women with other causes of acute chest pain more accurately remains unknown. OBJECTIVE To improve the management of suspected AMI in women by exploring sex-specific CPCs. DESIGN, SETTING, AND PARTICIPANTS: From April 21, 2006, through August 12, 2012, we enrolled 2475 consecutive patients (796 women and 1679 men) presenting with acute chest pain to 9 emergency departments in a prospective multicenter study. The final diagnosis of AMI was adjudicated by 2 independent cardiologists. INTERVENTIONS: Treatment of AMI in the emergency department. MAIN OUTCOMES AND MEASURES: Sex-specific diagnostic performance of 34 predefined and uniformly recorded CPCs in the early diagnosis of AMI. RESULTS: Acute myocardial infarction was the adjudicated final diagnosis in 143 women (18.0%) and 369 men (22.0%). Although most CPCs were reported with similar frequency in women and men, several CPCs were reported more frequently in women (P < .05). The accuracy of most CPCs in the diagnosis of AMI was low in women and men, with likelihood ratios close to 1. Thirty-one of 34 CPCs (91.2%) showed similar likelihood ratios for the diagnosis of AMI in women and men, and only 3 CPCs (8.8%) seemed to have a sex-specific diagnostic performance with P < .05 for interaction. These CPCs were related to pain duration (2-30 and >30 minutes) and dynamics (decreasing pain intensity). However, because their likelihood ratios were close to 1, the 3 CPCs did not seem clinically helpful. Similar results were obtained when examining combinations of CPCs (all interactions, P ≥ .05). CONCLUSIONS AND RELEVANCE: Differences in the sex-specific diagnostic performance of CPCs are small and do not seem to support the use of women-specific CPCs in the early diagnosis of AMI. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00470587.

Serial changes in high-sensitivity cardiac troponin I in the early diagnosis of acute myocardial infarction.

BACKGROUND: Current guidelines require a change (rise and/or fall) in levels of cardiac troponin (cTn) for the diagnosis of acute myocardial infarction (AMI). It is unknown whether absolute or relative changes provide higher accuracy when using high-sensitivity cTnI assays. METHODS: In a prospective international multicentre study, we assessed the diagnostic accuracy of early absolute and relative changes in cTnI measured with two novel pre-commercial high-sensitivity assays (Siemens and Beckman Coulter) in 943 unselected patients presenting to the ED with suspected AMI. The final diagnosis of AMI was adjudicated using all available data including serial hs-cTnT levels by two independent cardiologists. RESULTS: The diagnostic accuracy of absolute changes in the diagnosis of AMI as quantified by the area under the receiver operating characteristics curve (AUC) was very high (e.g. at 2 h, Siemens high-sensitivity cTnI AUC 0.93, 95%Cl 0.90-0.96; Beckman Coulter high-sensitivity cTnI AUC 0.93, 95%Cl 0.90-0.96) and superior to relative changes at all time points (p < 0.001). The results were consistent in clinically important subgroups. Direct comparison of the absolute changes in the two high-sensitivity cTnI assays showed similar accuracy. When combined with the baseline cTnI levels, the difference between absolute and relative changes became much smaller and remained statistically significant only for the Siemens assay. CONCLUSIONS: As single variables early absolute changes in high-sensitivity cTnI levels have significantly higher diagnostic accuracy than relative changes. When combined with the baseline cTn level, reflecting clinical practice, both absolute and relative changes provided very high accuracy with much smaller differences between both approaches.

Rapid rule out of acute myocardial infarction using undetectable levels of high-sensitivity cardiac troponin.

BACKGROUND: We examined whether undetectable levels of high-sensitivity cardiac Troponin (hs-cTn) can be used to rule out acute myocardial infarction (AMI) with a single blood draw at presentation to the emergency department (ED). METHODS AND RESULTS: In a prospective multicenter study we used 4 different hs-cTn assays (hs-cTnT Roche, and hs-cTnI Siemens, hs-cTnI Beckman Coulter and hs-cTnI Abbott) in consecutive patients presenting with acute chest pain. The final diagnosis of AMI was adjudicated by two independent cardiologists using all available data including serial hs-cTnT levels. Mean follow up was 24 months. Among 2072 consecutive patients with available hs-cTnT levels, 21% had an adjudicated diagnosis of AMI. Among AMI patients, 98.2% had initially detectable levels of hs-cTnT (sensitivity 98.2%, 95%CI 96.3%-99.2%, negative predictive value (NPV) 98.6%, 95%CI 97.0%-99.3%). Undetectable levels of hs-cTnT ruled out AMI in 26.5% of patients at presentation. The NPV was similar with the three hs-cTnI assays: among 1180 consecutive patients with available hs-cTnI (Siemens), the NPV was 98.8%; among 1151 consecutive patients with available hs-cTnI (Beckman Coulter), the NPV was 99.2%; among 1567 consecutive patients with available hs-cTnI (Abbott), the NPV was 100.0%. The percentage of patients with undetectable levels of hs-cTnI was similar among the three hs-cTnI assays and ranged from 11.4% to 13.9%. CONCLUSIONS: Undetectable levels of hs-cTn at presentation have a very high NPV and seem to allow the simple and rapid rule out of AMI. This criteria applies to much more patients with hs-TnT as compared to the investigated hs-cTnI assays.

Normal presenting levels of high-sensitivity troponin and myocardial infarction.

OBJECTIVE: To analyse whether levels of high-sensitivity cardiac troponin (hs-cTn) below their respective 99th percentile can be used as a single parameter to rule out acute myocardial infarction (AMI) at presentation. DESIGN: Prospective, multicentre study. MAIN OUTCOME MEASURES: We measured hs-cTn using four different methods (hs-cTnT Roche, hs-cTnI Siemens, hs-cTnI Beckman Coulter and hs-cTnI Abbott) in consecutive patients presenting to the emergency department with acute chest pain. Two independent cardiologists adjudicated the final diagnosis. Patients were followed for death or AMI during a mean period of 24 months. RESULTS: Among 2072 consecutive patients with hs-cTnT measurements available, 21.4% had an adjudicated diagnosis of AMI (sensitivity 89.6%, 95% CI 86.4% to 92.3%, negative predictive value (NPV): 96.5%, 95% CI 95.4% to 97.4%). Among 1180 consecutive patients with hs-cTnI Siemens measurements available, 20.0% had AMI (sensitivity 94.1%, 95% CI 90.3% to 96.7%, NPV: 98.0%, 95% CI: 96.6% to 98.9%). Among 1151 consecutive patients with hs-cTnI Beckman Coulter measurements available, 19.7% had AMI (sensitivity 92.1%, 95% CI 87.8% to 95.2%, NPV: 97.5%, 95% CI 96.0% to 98.5%). Among 1567 consecutive patients with hs-cTnI Abbott measurements available, 20.0% had AMI (sensitivity 77.2%, 95% CI 72.1% to 81.7%, NPV: 94.3%, 95% CI 92.8% to 95.5%). CONCLUSIONS: Normal hs-cTn levels at presentation should not be used as a single parameter to rule out AMI as 6%-23% of adjudicated AMI cases had normal levels of hs-cTn levels at presentation. Our data highlight the lack of standardisation among hs-cTnI assays resulting in substantial differences in sensitivity and NPV at the 99th percentile.

Validation of high-sensitivity troponin I in a 2-hour diagnostic strategy to assess 30-day outcomes in emergency department patients with possible acute coronary syndrome.

OBJECTIVES: The study objective was to validate a new high-sensitivity troponin I (hs-TnI) assay in a clinical protocol for assessing patients who present to the emergency department with chest pain. BACKGROUND: Protocols using sensitive troponin assays can accelerate the rule out of acute myocardial infarction in patients with low-risk (suspected) acute coronary syndrome (ACS). METHODS: This study evaluated 2 prospective cohorts of patients in the emergency department with ACS in an accelerated diagnostic pathway integrating 0- and 2-h hs-TnI results, Thrombolysis In Myocardial Infarction (TIMI) risk scores, and electrocardiography. Strategies to identify low-risk patients incorporated TIMI risk scores= 0 or ≤ 1. The primary endpoint was a major adverse cardiac event (MACE) within 30 days. RESULTS: In the primary cohort, 1,635 patients were recruited and had 30-day follow-up. A total of 247 patients (15.1%) had a MACE. The finding of no ischemic electrocardiogram and hs-TnI ≤ 26.2 ng/l with the TIMI = 0 and TIMI ≤ 1 pathways, respectively, classified 19.6% (n = 320) and 41.5% (n = 678) of these patients as low risk; 0% (n = 0) and 0.8% (n = 2) had a MACE, respectively. In the secondary cohort, 909 patients were recruited. A total of 156 patients (17.2%) had a MACE. The TIMI = 0 and TIMI ≤ 1 pathways classified 25.3% (n = 230) and 38.6% (n = 351), respectively, of these patients as low risk; 0% (n = 0) and 0.8% (n = 1) had a MACE, respectively. Sensitivity, specificity, and negative predictive value for TIMI = 0 in the primary cohort were 100% (95% confidence interval [CI]: 98.5% to 100%), 23.1% (95% CI: 20.9% to 25.3%), and 100% (95% CI: 98.8% to 100%), respectively. Sensitivity, specificity, and negative predictive value for TIMI ≤ 1 in the primary cohort were 99.2 (95% CI: 97.1 to 99.8), 48.7 (95% CI: 46.1 to 51.3), and 99.7 (95% CI: 98.9 to 99.9), respectively. Sensitivity, specificity, and negative value for TIMI ≤ 1 in the secondary cohort were 99.4% (95% CI: 96.5 to 100), 46.5% (95% CI: 42.9 to 50.1), and 99.7% (95% CI: 98.4 to 100), respectively. CONCLUSIONS: An early-discharge strategy using an hs-TnI assay and TIMI score ≤ 1 had similar safety as previously reported, with the potential to decrease the observation periods and admissions for approximately 40% of patients with suspected ACS. (Advantageous Predictors of Acute Coronary Syndromes Evaluation [APACE] Study, NCT00470587; A 2 hr Accelerated Diagnostic Protocol to Assess patients with chest Pain symptoms using contemporary Troponins as the only biomarker [ADAPT]: a prospective observational validation study, ACTRN12611001069943).