Direct Comparison of High-Sensitivity-Cardiac-Troponin I vs. T for the Early Diagnosis of Acute Myocardial Infarction
What is the diagnostic accuracy of high-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity cardiac troponin T (hs-cTnT) for non–ST-segment elevation myocardial infarction (NSTEMI)?
This was an analysis of patients enrolled in PACE (Advantageous Predictors of Acute Coronary Syndrome Evaluation), an ongoing prospective international multicenter study. Eligible patients presenting with acute chest pain had measurement of cTnI and cTnT. Final diagnosis was adjudicated by two independent cardiologists. The primary prognostic endpoint was all-cause mortality during 24-month follow-up. Multiple statistical methods were used to characterize prognostic accuracy of the two high-sensitivity assays.
hs-cTnI showed higher diagnostic accuracy (area under the curve [AUC], 0.92; 95% confidence interval [CI], 0.89-0.94) when compared with hs-cTnT (AUC, 0.89; 95% CI, 0.86-0.91) in early presenters (<3 hours since chest pain onset). The converse was true for late presenters; hs-cTnT was superior (AUC, 0.96; 95% CI, 0.94-0.96), compared to cTnI (AUC, 0.94; 95% CI, 0.93-0.95). Prognostic accuracy for predicting all-cause mortality at 24-month follow-up was significantly high 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).
While both hs-cTnI and hs-cTnT provide high diagnostic and prognostic accuracy in patients presenting with NSTEMI, there are differences in their performance.
This is a useful comparison of two hs-cTn assays (which have yet to be approved for clinical use in the United States). The subtle differences between the two assays are of unclear significance. The diagnostic superiority of hs-cTnI in early presenters warrants further scrutiny and consideration; the early recognition of AMI is certainly important. On balance, though, the authors summarize the potential impact of their work well by writing, ‘The observed differences should not distract from the enormous amount of similarities between hs-cTnI and hs-cTnT, neither should they be misinterpreted as a suggestion to use two hs-cTn assays in parallel.’
Clinical Topics: Acute Coronary Syndromes
Keywords: Acute Coronary Syndrome, Follow-Up Studies, Troponin I, Troponin T, Confidence Intervals
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