Early diagnosis of MI using serial troponin measurements

The recent introduction of high sensitivity troponin assays (hsT) has improved the sensitivity of this assay for the detection of myocardial infarction, whilst simultaneously decreasing specificity.  To overcome this problem, the use of troponin kinetics – to identify acute myocardial damage  – has been proposed, either alone or in combination with other diagnostic markers of cardiovascular disease.

1818 patients with suspected acute coronary syndromes were recruited from three German hospitals between 2007 and 2008.  Each patient had blood drawn for the detection of twelve biomarkers, including both normal (cTnI)  and high sensitivity (hsTnI) troponin, on admission and at 3 and 6 hours.  The main outcome measure was  the diagnostic performance of baseline and serial changes in hsTnI and cTnI results at 3 hours after admission to the emergency department.

Of the 1818 patients, 413 (22.7%) were diagnosed as having had a myocardial infarction.  The use of hsTnI at admission was found to have a sensitivity of 82.3% and a negative predictive value of 94.7%. By comparison, the use of cTnI  at admission had a sensitivity of 79.4% and a negative predictive value of 94.0%. However, when levels were taken 3 hours after admission, the sensitivity was 98.2% and the negative predictive value was 99.4% for both hsTnI and cTnI assays. By combining the 99th percentile cutoff at admission with the serial change in troponin concentration within 3 hours, the positive predictive value for hsTnI increased from 75.1% at admission to 95.8% after 3 hours, and for cTnI increased from 80.9% at admission to 96.1% after 3 hours.

Conclusions:

Among patients with suspected acute coronary syndromes, a serial change in hsTnI or cTnI levels from admission to 3 hours after admission may facilitate an early diagnosis of myocardial infarction.

  • Keller T, Zeller T, Ojeda F et al.  Serial Changes in Highly Sensitive Troponin I Assay and Early Diagnosis of Myocardial Infarction.  JAMA.2011;306(24):2684-2693. doi:10.1001/jama.2011.1896