From the Guidelines
Elevated troponin levels indicate heart muscle damage, and any elevation is significant and requires immediate medical attention to determine the cause and appropriate treatment. Troponin is a protein released into the bloodstream when heart cells are injured, most commonly due to a heart attack (myocardial infarction) 1. Normal troponin levels are very low or undetectable in healthy individuals. Besides heart attacks, elevated troponin can occur in conditions like heart failure, myocarditis (heart inflammation), pulmonary embolism, sepsis, kidney failure, or after strenuous exercise 1.
Key Points to Consider
- The degree of elevation often correlates with the extent of heart damage, and serial measurements help determine if levels are rising, falling, or stable 1.
- This trend provides valuable diagnostic information, and doctors will typically perform an ECG, additional blood tests, and possibly imaging studies to assess heart function and determine the underlying cause of the troponin elevation 1.
- Elevated troponin levels are associated with an increased risk of death and reinfarction, and the risk of death is also correlated with the degree of troponin elevation 1.
- In patients with COVID-19, elevated troponin levels are associated with increased mortality, but the cause of this elevation has not been fully elucidated and may result from entities other than acute plaque disruption, including myocarditis, stress cardiomyopathy, acute heart failure, direct injury from SARS-CoV-2, and so on 1.
Clinical Implications
- Any detectable elevation of cardiac troponin is associated with an increased risk of death and reinfarction, and the risk of death is also correlated with the degree of troponin elevation 1.
- The 99th percentile of the upper reference level is the appropriate cutpoint for considering myocardial necrosis, and evidence for a serial increase or decrease ≥20% is required if the initial value is elevated 1.
- In the diagnosis of NSTEMI, cardiac troponin values must manifest an acute pattern consistent with the clinical events, including ischemic symptoms and electrocardiographic changes 1.
From the Research
Elevated Troponin Levels
Elevated troponin levels are highly sensitive and specific markers for acute myocardial infarction (AMI) 2, 3, 4, 5, 6. However, a wide range of non-AMI conditions can also cause significant elevations in cardiac troponins 2, 3, 5, 6.
Indications of Elevated Troponin Levels
- Myocardial injury or damage 2, 3, 4, 5, 6
- Acute myocardial infarction (AMI) 2, 3, 4, 5, 6
- Myocardial cell damage 6
- Other disease states, such as pericarditis, myocarditis, pulmonary embolism, and cardiomyopathy 3, 5, 6
Diagnostic Considerations
- Elevated troponin levels alone cannot establish a diagnosis of myocardial infarction (MI) 3, 4, 5, 6
- Clinical presentation and electrocardiogram (ECG) must be taken into account 3, 5, 6
- Corresponding clinical evidence of acute myocardial ischemia is required for the diagnosis of myocardial infarction 4, 6
- Highly sensitive troponin assays can detect myocardial infarction more frequently and earlier, and can also rule out myocardial infarction with higher diagnostic accuracy 6