ACCF 2012 Expert Consensus Document on Practical Clinical Considerations in the Interpretation of Troponin Elevations Date Posted:
The following are 10 points to remember from an Expert Consensus Document on interpretation of troponin elevations:
1. Even though elevated troponin is a sensitive and specific indication of cardiac myonecrosis, by itself, it does not indicate a myocardial infarction (MI) (myonecrosis due to ischemia) or any specific etiology.
2. The ‘Third Universal Definition of Myocardial Infarction’ (2012) classifies 5 types of MI: Type 1 is termed spontaneous, related to ischemia due to a primary coronary event (e.g., plaque rupture); Type 2 is secondary to increased oxygen demand or decreased supply; Type 3 is associated with sudden unexpected cardiac death; Type 4a is associated with percutaneous coronary intervention (PCI); Type 4b is associated with stent thrombosis; and Type 5 is associated with coronary artery bypass grafting (CABG) surgery.
3. An elevated troponin level that is ‘smoldering’ and relatively constant over an appropriate sampling interval is more likely to be caused by chronic diseases (e.g., heart failure) versus ischemia.
4. A 20% change at 3-6 hours from the baseline value may be suggestive of MI. That said, there is insufficient evidence to provide concrete guidelines on how to differentiate between acute coronary syndrome (ACS) and non-ACS ischemia-induced troponin elevations without accounting for the clinical circumstances.
5. It is imperative to incorporate troponin testing into global risk assessment. Those patients with an elevated troponin and a high pretest probability of ACS are most likely to derive benefit from a treatment strategy that targets coronary thrombosis.
6. The 2012 universal definition of MI recommends the following for defining a PCI-related MI (Type 4a): a troponin elevation within 48 hours post-procedure of >5x upper limit of normal (ULN) with either symptoms of myocardial ischemia, new ischemic electrocardiographic changes, or documented complications during the procedure.
7. The 2012 universal definition of MI recommends the following for CABG-related MI (Type 5): troponin elevation >10x ULN when there are corresponding changes on ECG, angiography, or imaging.