High-sensitivity cardiac troponin T compared with standard troponin T testing on emergency department admission: how much does it add in everyday clinical practice?

Abstract

Background: We compared high-sensitivity cardiac troponin T (hs-cTnT) and standard cTnT for acute myocardial infarction (AMI) diagnosis in everyday clinical practice of an emergency department (ED).

Methods and results: cTnT was measured in 2384 consecutive patients (60 ± 21 years, 52% female) on ED admission. Readmissions to the ED (n=720) and mortality (n=101) were followed for an average period of 239 ± 49 days. There were 53 AMIs (delay, 1 to 96 hours; median, 3 hours), 440 chest pain patients, 286 dyspnea patients, 785 acute or chronic cardiac diseases, and 540 neurological diseases, with the remaining having various internal diseases. The diagnostic performances of hs- and standard cTnT were comparable for AMI diagnosis (area under receiver operating characteristics curves [ROC AUC], 0.91 ± 0.02 versus 0.90 ± 0.03; P=0.31). Using the 99th-percentile cutoff, the sensitivities and specificities for AMI in the whole population were 91% and 74% for hs-cTnT and 89% and 80% for standard cTnT. hs-cTnT detected significantly more patients with cardiac diseases (ROC AUC, 0.77 ± 0.01 versus 0.67 ± 0.01; P<0.001). hs-cTnT and standard cTnT were significant predictors of ED readmissions but not of mortality, but both were not independent predictors of ED readmissions or the combined end point of readmission or mortality in binary logistic regression analysis.

Conclusions: In unselected ED patients the diagnostic performances of hs-cTnT and standard cTnT for AMI diagnosis did not differ significantly. hs-cTnT detected significantly more cardiac diseases. hs-cTnT and standard cTnT were not independent predictors of ED readmissions and mortality from all causes.

Keywords: cardiac troponin T; diagnosis; emergency department; high sensitivity; myocardial infarction; risk stratification.

Figure 1.

Passing and Bablok regression analysis for the analytical comparison of the hs‐cTnT and standard cTnT (fourth‐generation) assays. A, There was a good agreement between both assays in the whole study group, with cTnT values above the lower limit of detection and below the dilution limit in both assays (hs‐cTnT=7.59+1.11×cTnT [fourth generation]; n=506). B, The agreement of both methods was weaker when values in the lower measuring range (>10 and <50 ng/L) of the fourth‐generation cTnT assay were compared (hs‐cTnT=3.05+1.36×cTnT (fourth generation); n=376). hs‐cTnT indicates high‐sensitivity cardiac troponin T.

Figure 2.

hs‐cTnT (A) and standard cTnT concentration distributions (B) in the different disease categories. Data given as box plots. hs‐cTnT and fourth‐generation cTnT concentrations of AMI patients were significantly higher compared with cTnT concentrations of all other disease groups (Kruskal–Wallis test, P<0.001). log fourth gen. cTnT indicates logarithmical fourth‐generation cardiac troponin T concentrations; log hs‐cTnT, logarithmical high‐sensitivity cardiac troponin T concentrations; AMI, acute myocardial infarction.

Figure 3.

ROC analysis of high‐sensitivity and standard cardiac troponin T for the detection of acute myocardial infarction (A) and cardiac diseases (B) in the whole study population. There were no significant differences between both assays for AMI detection (A), but hs‐cTnT detected significantly more patients with any cardiac diseases (B). ROC indicates receiver operating characteristics; AMI, acute myocardial infarction; hs‐cTnT, high‐sensitivity cardiac troponin T.