Laboratory Tests and Medications for Chest Pain Occurring One Week Ago
For a patient with chest pain that occurred one week ago, the recommended initial laboratory tests include cardiac troponin (preferably high-sensitivity), complete blood count, and basic chemistry, along with an electrocardiogram (ECG) and chest radiograph to evaluate for cardiac and non-cardiac causes.
Initial Diagnostic Evaluation
- A chest radiograph is useful to evaluate for cardiac, pulmonary, and thoracic causes of chest pain, including pneumonia, pneumothorax, or rib fractures 1
- Serial cardiac troponin measurements are essential, with high-sensitivity troponin (hs-cTn) being the preferred biomarker due to its greater diagnostic accuracy and more rapid detection of myocardial injury 1
- For conventional troponin assays, measurements should be taken 3-6 hours apart; for high-sensitivity troponin, 1-3 hours between measurements is recommended 1
- Institutions should implement a standardized chest pain diagnostic protocol that includes specific troponin sampling based on their particular assay 1
- A single hs-cTn concentration below the limit of detection may be sufficient to exclude myocardial injury if symptoms began at least 3 hours before presentation 1
- Creatine kinase myocardial (CK-MB) isoenzyme and myoglobin are not useful for diagnosis when cardiac troponin is available 1
Risk Stratification
- Patients should be categorized based on their 30-day risk of death or major adverse cardiovascular events (MACE) 1
- Low-risk patients have <1% 30-day risk of death or MACE and may be discharged without admission or urgent cardiac testing 1
- For intermediate-risk patients, transthoracic echocardiography (TTE) is recommended to establish baseline ventricular and valvular function, evaluate for wall motion abnormalities, and assess for pericardial effusion 1
- Management in an observation unit is reasonable for intermediate-risk patients to shorten length of stay and lower costs 1
Medication Recommendations
- Aspirin 75-500mg should be administered if not contraindicated (no history of allergy or recent bleeding) 2
- For patients with suspected acute coronary syndrome (ACS), low molecular weight heparin or unfractionated heparin should be administered 2
- Beta-blockers should be considered if there are no contraindications, particularly with tachycardia or hypertension 2
- Pain relief with morphine given intravenously is recommended for severe pain, titrated according to severity 2
- Supplemental oxygen should be provided if oxygen saturation is low (<94%) 2
Further Testing Based on Risk Assessment
- For patients with non-diagnostic initial evaluation but intermediate risk, stress testing options include:
- Coronary CT angiography (CCTA) is an alternative to functional testing in appropriate patients 1
Important Considerations and Pitfalls
- Pain severity is a poor predictor of imminent complications such as cardiac arrest 2
- Elderly patients or those with diabetes may present with atypical symptoms 2
- A normal ECG does not exclude significant coronary artery disease, particularly left circumflex or right coronary artery occlusions 1
- Clinicians should be familiar with the analytical performance and the 99th percentile upper reference limit that defines myocardial injury for the troponin assay used at their institution 1
- For patients with chest pain occurring one week ago who are currently asymptomatic, risk stratification should still be performed as delayed presentations of ACS are common 1
Specific Contraindications to Testing Modalities
- Exercise ECG is contraindicated in patients with abnormal ST changes on resting ECG, left bundle branch block, or inability to achieve adequate exercise levels 1
- Stress nuclear imaging is contraindicated in patients with significant arrhythmias or contraindications to vasodilator administration 1
- CCTA is contraindicated in patients with allergy to iodinated contrast, renal impairment, or inability to cooperate with scan acquisition 1