From the Guidelines
Troponin measurement is crucial in evaluating patients with sternal fractures to identify potential cardiac injury, and I recommend obtaining troponin levels on admission and serially at 3-6 hour intervals for at least 24 hours, even in the absence of obvious cardiac symptoms. In patients with sternal fractures, the proximity of the sternum to the heart increases the risk of cardiac injury, and troponin levels can help detect myocardial damage 1. Elevated troponin levels (typically >0.04 ng/mL, though laboratory reference ranges may vary) indicate myocardial injury and should prompt further cardiac evaluation including ECG, echocardiography, and cardiology consultation 1.
Key Points to Consider
- Blunt cardiac injury occurs in approximately 20-30% of patients with sternal fractures, and troponin is more sensitive than ECG alone for detecting this injury 1.
- Even in hemodynamically stable patients with normal ECGs, elevated troponin levels can identify patients at risk for cardiac complications who require closer monitoring 1.
- Patients with normal serial troponin levels and no ECG abnormalities generally have excellent cardiac prognosis despite their sternal fracture 1.
- The use of cardiac troponin as a biomarker for myocardial necrosis is preferred due to its improved sensitivity and superior tissue-specificity compared to other biomarkers 1.
Recommendations
- Obtain troponin levels on admission and serially at 3-6 hour intervals for at least 24 hours in patients with sternal fractures 1.
- Use elevated troponin levels as an indicator for further cardiac evaluation, including ECG, echocardiography, and cardiology consultation 1.
- Consider the clinical significance of troponin elevation in sternal fractures and the potential for cardiac complications, even in hemodynamically stable patients with normal ECGs 1.
From the Research
Role of Troponin in Sternal Fracture
- Troponin is used in conjunction with electrocardiogram (ECG) to detect myocardial contusion and arrhythmia in patients with sternal fracture 2.
- Serum troponin I administered 4 to 8 hours after chest trauma is recommended as an effective means of detecting substantial arrhythmia secondary to myocardial contusion 2.
- Elevated troponin levels are associated with an increased risk of complications secondary to myocardial contusion, and its use is suggested to identify patients at risk 2.
Diagnosis and Management
- The use of troponin in conjunction with ECG is suggested for patients with sternal fracture to detect myocardial contusion and arrhythmia 2.
- A study found that 24-hour telemetry monitoring may not be necessary for patients with isolated sternal fracture and minor ECG abnormalities or troponin elevation 3.
- Another study found that routine admission of patients with isolated sternal fractures for observation is often unnecessary, and that non-invasive cardiac monitoring can influence management 4, 5.
Clinical Significance
- Elevated troponin levels are not always associated with adverse outcomes, and may lead to unnecessary hospitalization 5.
- Echocardiogram can be used as a diagnostic and triage tool in patients with sternal fracture, especially those with associated injuries 6.
- Pericardial effusion found on echocardiogram may not always be associated with clinical cardiac significance, and patients with "benign" pericardial effusion can be discharged as soon as their medical condition improves 6.