How good is Troponin T or I to rule out acute coronary syndrome in the emergency room when a patient presents within two to three hours after the onset of symptoms ?
- Very useful
- Useful
- Rarely useful
- Not useful
- Not at all useful
The answer is 5 , can be 3 or 4 , never 1 or 2 !
If you are surprised with the answer
Findout why , read further
Final message
Troponin has a definite diagnostic and prognostic value in STEMI or NSTEMI but relying on a single normal troponin level very early after an ACS can be . . . futile.
Realis, diagnosis of ACS , especially STEMI , is primarily by ECG and clinical features . Even in NSTEMI biomarkers help primarily to risk stratify the event. Bio markers come into picture only in borderline ECGs and in baseline ECG defect like LBBB/Pacing rhythm .
It should be recognised , the major draw back of cardiac markers is , it does not represent real time cardiac myocyte events. (But the good old ECG has this unique property !) .The myocyte secretion & release kinetics , the effect of native (and pharmocological ) reperfusion make it a unreliable marker.Apart from the time lag , the laboratory methods to detect these molecule needs further refinement.
For the current day cardiologists , it is required to finish off the entire treatment of MI within 6 hours by doing a primary PCI . It is an irony , troponin begins to appear only by then to be detected in the blood !
Further reading
A .All about troponin
http://www.annals.org/cgi/content/full/142/9/786
B.Troponin In aortic dissection
Dr.S.Venkatesan MD 