From the Guidelines
Management of a patient with elevated troponin levels and suspected NSTEMI requires prompt initiation of dual antiplatelet therapy with aspirin and a P2Y12 inhibitor, such as ticagrelor or clopidogrel, as well as anticoagulation with unfractionated heparin, low molecular weight heparin, or fondaparinux, as recommended by the 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes 1. The diagnosis of NSTEMI is established if a biomarker of myocardial necrosis, such as troponin, has been released, and the patient presents with symptoms suggestive of acute coronary syndrome (ACS) and electrocardiographic ST-segment depression or prominent T-wave inversion 1. Key considerations in the management of NSTEMI include:
- Risk stratification using tools like the GRACE or TIMI score to determine the timing of coronary angiography, with high-risk patients requiring intervention within 24 hours 1
- Continuous cardiac monitoring, serial ECGs, and troponin measurements to detect evolving myocardial injury 1
- Pain management with nitroglycerin and morphine as necessary
- Additional medications, including high-intensity statins, beta-blockers, and ACE inhibitors or ARBs for patients with left ventricular dysfunction The 2014 AHA/ACC guideline also recommends the use of a GP IIb/IIIa inhibitor at the time of PCI in patients with NSTE-ACS and high-risk features, such as elevated troponin, who are not adequately pretreated with clopidogrel or ticagrelor 1. It is essential to note that solitary elevations of troponin cannot be assumed to be due to MI, as troponin elevations can be caused by various conditions, including tachyarrhythmia, hypotension or hypertension, cardiac trauma, acute heart failure, myocarditis, and pericarditis, as well as severe noncardiac conditions such as sepsis, burns, respiratory failure, acute neurological diseases, and drug toxicity 1.
From the Research
Diagnosis Approach
- The diagnosis of Non-ST-Elevation Myocardial Infarction (NSTEMI) involves the assessment of elevated troponin levels, which is a marker of myocardial injury 2, 3, 4.
- However, elevated troponin levels can also be caused by conditions other than NSTEMI, such as heart failure, dysrhythmia, and dissection, as well as non-cardiac conditions like pulmonary embolism, sepsis, and stroke 2, 3.
- Clinicians should consider the clinical context, patient symptoms, electrocardiogram, and ultrasound in their assessment of the patient with troponin elevation to avoid misdiagnosis 2, 3.
Management Approach
- The management of patients with suspected NSTEMI and elevated troponin levels involves a combination of anticoagulant and antiplatelet agents, such as aspirin, clopidogrel, and enoxaparin 5, 6.
- Reduced-dose enoxaparin combined with dual-antiplatelet therapy followed by triple-antiplatelet therapy alone during subsequent percutaneous coronary intervention (PCI) appears safe and may prove efficacious 5.
- New P2Y12 receptor inhibitors, such as prasugrel and ticagrelor, have clear benefits compared with clopidogrel for dual antiplatelet therapy, and cangrelor or vorapaxar may be of value in specific settings 6.
Key Considerations
- Elevated troponin levels are a marker of poor outcomes, including increased rates of mortality, and clinicians should consider the clinical context and other factors to avoid misdiagnosis 2, 3, 4.
- The combination of aspirin, clopidogrel, and low-dose rivaroxaban has recently been approved for secondary prevention after acute coronary syndrome (ACS) in some regions 6.
- Strategies to balance the potential benefit of antithrombotic therapy against the risk of bleeding complications are being developed, such as radial access in coronary angiography or restricted use of combination therapy 6.