Diagnostic and prognostic value of the sex-specific 99th percentile of four high-sensitivity cardiac troponin assays in patients with suspected myocardial infarction.

AIMS: High-sensitivity cardiac troponin (hs-cTn) assays are used for detection of myocardial infarction (MI). Ninety-ninth percentiles show wide inter-assay variation. The use of sex-specific cut-offs is recommended as definitory cut-off for MI. We compared diagnostic performance and prognostic value of sex-specific 99th percentiles of four hs-cTn assays in patients with suspected MI. METHODS AND RESULTS: Concentrations of four hs-cTn assays were measured at presentation and after 3 h in patients with suspected MI. Final diagnoses were adjudicated according to the 4th Universal Definition of MI. Unisex and sex-specific 99th percentiles were evaluated as diagnostic cut-offs following the ESC 0/3 h algorithm. These cut-offs were used in Cox-regression analyses to investigate the association with a composite endpoint of MI, revascularization, cardiac rehospitalization, and death. Non-ST-elevation MI was diagnosed in 368 of 2718 patients. Applying the unisex 99th percentile, Elecsys hs-cTnT provided highest negative predictive value (NPV) of 99.7 and a positive predictive value (PPV) of 75.9. The analysed hs-cTnI assays showed slightly lower NPVs and comparable PPVs [Architect (NPV 98.0, PPV of 71.4); Atellica (NPV 97.7, PPV of 76.1); Pathfast (NPV 97.7, PPV of 66.6)]. Application of sex-specific 99th percentiles did not significantly affect diagnostic performance. Concentrations above 99th percentile were independent predictors for impaired long-term outcome (hazard ratios 1.2-1.5, P < 0.001). CONCLUSION: We describe a good diagnostic accuracy of four hs-cTn assays using the assay-specific 99th percentile for detection of MI. Application of sex-specific 99th percentiles did neither affect diagnostic performance nor prognostic value significantly. Finally, values above the 99th percentile were associated with poor long-term outcome.

Validation of a 0/1 h Algorithm for Rapid Diagnosis of Myocardial Infarction Using a High-Sensitivity Troponin I Assay.

BACKGROUND: Current guidelines recommend 0/1 h algorithms using high-sensitivity cardiac troponin (hs-cTn) for fast diagnosis of myocardial infarction (MI). Yet, for some assays, existing data is limited. We aimed to evaluate the diagnostic performance and the prognostic value of a rapid 0/1 h algorithm for the Access hs-cTnI assay. METHODS: In consecutive patients presenting with suspected MI, we measured concentrations of Access hs-cTnI at presentation and after 1 hour. Final diagnosis was adjudicated independently by 2 cardiologists. Parameters for diagnostic performance were calculated, applying the recently derived European Society of Cardiology (ESC) 0/1 h algorithm for Access hs-cTnI. Additionally, we assessed the prognostic utility of Access hs-cTnI for the composite end point of all-cause mortality and incident MI at 3 years. RESULTS: In 1879 patients, 257 non-ST-elevation MIs occurred. Application of the 0/1 h algorithm classified 44.5% as rule-out, 20.3% as rule-in, and triaged 35.1% to the observe group. High rule-out safety was confirmed with a sensitivity of 97.7% (95% CI, 95.0%-99.1%) and a negative predictive value of 99.3% (95% CI, 98.4%-99.7%). Rule-in capacity was moderate with a specificity of 88.0% (95% CI, 86.3%-89.6%) and a positive predictive value of 50.8% (95% CI, 45.7%-55.9%). After exclusion of patients with ST-elevation MI the results showed strong prognostic value, even after adjustment for cardiovascular risk factors and comorbidities, with adjusted hazard ratios of 2.51 (95% CI, 1.56-4.04) in the observe and 3.55 (95% CI, 2.18-5.79) in the rule-in group for the composite end point of all-cause mortality and incident MI at 3 years, compared to ruled-out patients. CONCLUSION: The ESC 0/1 h algorithm for Access hs-cTnI allows safe and efficient triage of patients with suspected MI and has strong prognostic utility up to 3 years after the initial evaluation.

Predictive Value of Serial ECGs in Patients with Suspected Myocardial Infarction.

The electrocardiogram (ECG) is an important diagnostic tool for patients with suspected acute myocardial infarction (AMI). Current guidelines recommend serial ECGs in case of persisting symptoms. We aimed to analyze the predictive value of ischemic ECG-signs in patients with suspected AMI. Patients presenting to the emergency department with suspected AMI were included. All patients with ST-elevation AMI were excluded from analyses. Patients received 12-lead-ECG and high-sensitive Troponin T (hs-TnT)-measurement at admission and after 3 h. Four groups were defined: no ischemic signs in either ECG; new ischemic signs in the second ECG; resolved ischemic signs in the second ECG; and persistent ischemic signs in both ECGs. Patients were followed for 2 years to assess the composite endpoint of all-cause-mortality, AMI, and coronary revascularization. Using a 30-day landmark analysis, a Cox regression with ischemic signs as the variable of interest, adjusted by cardiovascular risk factors, was calculated. Of 1675 patients, 1321 showed no ischemic signs, in 25 new-, in 92 resolved- and in 237 patients, persistent ischemic signs were documented. Patients with persistent ischemic signs had significantly worse outcomes, compared to those without. Compared to no ischemic signs, adjusted hazard ratios for the combined endpoint were 0.81 (95% CI 0.20, 3.31; p-value = 0.77) for new-, 0.59 (95% CI 0.26, 1.34; p-value = 0.21) for resolved-, and 1.47 (95% CI 1.102, 2.13; p-value = 0.041) for persistent ischemic signs. In patients with suspected AMI, persistent ischemic ECG-signs are predictive of a higher rate of all-cause-mortality, AMI, and revascularization.