From the Guidelines
I strongly recommend waiting for a delta 2-hour troponin before initiating the ACS protocol. The patient's initial troponin I of 22 ng/L is only mildly elevated and falls within the "indeterminate range" for many assays. Since the chest pain has resolved, the ECG is normal, and there is no cardiac history, serial troponin testing is appropriate to determine if there is a significant rise or fall in levels, which would be more indicative of acute myocardial injury 1.
Key Considerations
- The use of troponins at 0 and 2 hours as a stand-alone measure for excluding the diagnosis of ACS is strongly discouraged 1.
- Negative high-sensitivity troponin I (hs-cTnI) measured at 0 and 2 hours may be used together with low-risk stratification to identify those patients who have a less than 1% 30-day risk of a major adverse cardiac event (MACE) 1.
Management While Waiting for Delta Troponin
While waiting for the repeat troponin, ensure the patient remains on continuous cardiac monitoring, maintain IV access, and consider administering aspirin 325 mg if not contraindicated. The delta troponin will help distinguish between acute coronary syndrome and other causes of mild troponin elevation such as renal dysfunction, sepsis, or pulmonary embolism.
Next Steps
If the repeat troponin shows a significant increase (typically >20% from baseline), then initiate the full ACS protocol including antiplatelet therapy, anticoagulation, and cardiology consultation for possible intervention. This approach is supported by the 2015 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations 1.
From the FDA Drug Label
The CURE study included 12,562 patients with ACS without ST-elevation (UA or NSTEMI) and presenting within 24 hours of onset of the most recent episode of chest pain or symptoms consistent with ischemia Patients were required to have either ECG changes compatible with new ischemia (without ST-elevation) or elevated cardiac enzymes or troponin I or T to at least twice the upper limit of normal.
The patient's troponin I level is 22 ng/L, which may not be elevated to at least twice the upper limit of normal. It is recommended to wait and get a delta 2 hr troponin to confirm the diagnosis of acute coronary syndrome (ACS) before starting the ACS protocol.
From the Research
Patient Evaluation
The patient, a 55-year-old female, presents to the emergency department with left-sided chest pain that has now resolved. She has no cardiac history, a normal ECG, but an elevated Troponin I level of 22 ng/L.
Risk Stratification
According to the study 2, the evaluation of chest pain in the emergency department should be systematic, risk-based, and goal-driven. The initial evaluation is based on the history, a focused physical examination, and the ECG. This information is sufficient to categorize patients into groups at high, moderate, and low risk.
Troponin Levels and ACS Protocol
The elevated Troponin I level indicates potential myocardial injury. However, the study 3 does not provide specific guidance on the timing of troponin levels in relation to the initiation of the ACS protocol.
Management of Acute Coronary Syndrome
The management of acute coronary syndrome (ACS) involves the use of antiplatelet agents, anticoagulants, and early revascularization, as stated in the study 4. Aspirin is recommended for all patients with suspected ACS, unless contraindicated. The addition of a second antiplatelet agent and parenteral anticoagulation is also recommended for most patients.
Decision to Start ACS Protocol
Given the patient's elevated troponin level and resolved chest pain, it is essential to consider the potential benefits and risks of initiating the ACS protocol. The study 5 suggests that an early invasive strategy in high-risk patients is associated with lower mortality over the long term. However, the patient's current risk stratification and the need for further evaluation, such as a delta 2-hour troponin, should be considered before making a decision.
Further Evaluation
The study 2 emphasizes the importance of a systematic evaluation program for patients with chest pain, including the use of additional methods to identify acute coronary syndromes in patients initially appearing at moderate or low risk. A delta 2-hour troponin may provide valuable information to guide further management and risk stratification.
- Key considerations:
- Elevated Troponin I level indicating potential myocardial injury
- Normal ECG and no cardiac history
- Resolved chest pain
- Need for further evaluation, such as a delta 2-hour troponin, to guide management and risk stratification
- Potential benefits and risks of initiating the ACS protocol, as outlined in studies 3, 4, and 5