New Roche Troponin Assay Has Proven Advantages for the Diagnosis of Acute Myocardial Infarction

Doctors in a specialist cardiology clinic in Heidelberg, Germany, have shown that the Elecsys® Troponin T high sensitive (hs) assay helps to identify more patients with acute myocardial infarction (AMI) earlier, compared to less sensitive 4th generation cardiac troponin assays.

This high sensitive assay for cardiac Troponin T (cTnT) offers excellent precision (<10% CV) at the 99th percentile reference limit of a healthy population, making it the first commercially available Troponin T assay to meet the recent ESC/ACCF/AHA/WHF* recommendations for the diagnosis of myocardial infarction (MI)1,2.

“The revised definition of MI recommends that elevations above the 99th percentile of the normal population should be measured with <10% coefficient of variation (CV). The Elecsys Troponin T hs assay was the only test available that offered this level of sensitivity and precision,” comments Dr Evangelos Giannitsis from the Cardiology Clinic at the University Hospital, Heidelberg.

“The improved performance of the high sensitive assay means that not only can we identify MI at an earlier opportunity, but we can also now identify more patients with MI (amongst those with symptoms of acute coronary syndrome (ACS)) than we could with the less sensitive assay. It also means that additional tests for MI/ischaemia markers are no longer required,” Dr Giannitsis adds.

The ESC/ACCF/AHA/WHF redefinition of MI requires an increase or decrease of cardiac troponin to be demonstrated in patients with symptoms of ACS, with at least one of the concentrations greater than the 99th percentile of the reference population. Dr Giannitsis and his team found that, when used in this way, the Elecsys Troponin T hs assay increased the number of non- ST segment myocardial infarction (NSTEMI) diagnoses and enabled earlier detection of evolving NSTEMI3.

“The increased sensitivity of the high sensitive assay reduces the specificity of a single test for MI,” continues Dr Giannitsis. “But I see this as a strong advantage. The test has 100% tissue specificity and so it is excellent for the identification of patients with sub-clinical disease manifestations, such as heart failure, valve disease, arterial hypertension and cardiac myopathies, which may also have an elevated cTnT. Interpretation of the high sensitive result should therefore consider the clinical presentation and the kinetics of the cTnT elevation. This is very helpful for distinguishing between chronic and acute disease. If there is a very rapid elevation or decline in cTnT between two measurements then this implies an acute condition such as AMI. If there is a more stable elevation, then it is more likely to be a chronic condition.”

“A raised cTnT measurement is also an important prognostic marker,” Dr Giannitsis stresses. “In high risk candidates it is extremely important to look for the reason for the elevation. It is not restricted to ACS and the treatment for non-MI patients would be very different.”

The cardiology clinic in Heidelberg now uses the Elecsys Troponin T hs assay routinely to test patients presenting with ACS.

The new Elecsys Troponin T hs assay is suitable for use on all cobas® and MODULAR ANALYTICS serum work areas. For further information, please contact the Roche Centralised Diagnostics Marketing team at 01444 256000 or visit the Roche website at www.roche-diagnostics.co.uk.

*ESC, European Society of Cardiology; ACCF, American College of Cardiology Foundation; AHA, American Heart Association; WHF, World Heart Federation

References:
1. Thygesen K, Alpert JS, White HD (2007) Joint ESC/ACCF/AHA/WHF Task Force for the Redefinition of Myocardial Infarction. Universal definition of myocardial infarction. Eur Heart J 28:2525–2538; J Am Coll Cardiol 50:2173–2195; Circulation 116: 2634–2653.
2. Giannitsis E, Kurz K, Hallermayer K, et al (2010) Analytical Validation of a High-Sensitivity Cardiac Troponin T Assay. Clin Chem 56(2): 254–261.
3. Giannitsis E, Becker M, Kurz K, et al (2010) High-Sensitivity Cardiac Troponin T for Early Prediction of Evolving Non–ST-Segment Elevation Myocardial Infarction in Patients with Suspected Acute Coronary Syndrome and Negative Troponin Results on Admission. Clin Chem 56(4) in press.