Troponin: Perhaps no other laboratory test has the authority to alter a patient's clinical course and cost of care so broadly. As the 2 case studies illustrate, an increased troponin concentration usually leads to concern for acute coronary syndrome and to evaluation with either stress testing or coronary artery imaging (or both), which in turn can lead to coronary artery revascularization (as with case 2). Indeed, it is broadly accepted that patients with an acute coronary syndrome and a troponin increase have a better outcome with an approach that includes medical management and coronary artery revascularization. Troponin assays are now exquisitely sensitive, and the assessment of the patient with an increased troponin value has become complicated. As the authors emphasize, “clinical judgment is essential.” A troponin increase should not automatically lead to either a hospital admission or a coronary angiogram.
The new troponin assays have exposed the vulnerability of the myocardial cell to stress (acute or chronic). Even running a marathon can lead to appreciable troponin release in an otherwise healthy heart (1). As the authors note, the list of conditions that cause troponin increases (dynamic or static) is substantial and ever increasing. This is an area of opportunity for research.
A by-product of the clinical use of the troponin assay has been the discovery of new conditions that cause acute myocardial injury, such as takotsubo cardiomyopathy. In this regard, cardiac MRI has been particularly valuable and has also improved diagnostic accuracy substantially for such uncommon conditions as coronary embolization and acute myocarditis (2).
In the end, an increased troponin concentration is not a diagnosis; rather, it is an indicator of myocardial injury or stress. The troponin assays have greatly improved, yet our patients are becoming older, with increasingly complex conditions. Understanding troponin increases in this setting is both a challenge and an opportunity.
Author Contributions: All authors confirmed they have contributed to the intellectual content of this paper and have met the following 3 requirements: (a) significant contributions to the conception and design, acquisition of data, or analysis and interpretation of data; (b) drafting or revising the article for intellectual content; and (c) final approval of the published article.
Authors' Disclosures or Potential Conflicts of Interest: No authors declared any potential conflicts of interest.
- Received for publication October 4, 2011.
- Accepted for publication October 7, 2011.
- © 2012 The American Association for Clinical Chemistry