Case: You’re seeing a 50-year-old male for the first time complaining of aching chest pain for the last three months. It’s intermittent, triggered by exertion and quickly relieved by rest. He has dyslipidemia and his mother had a heart attack at age 60. You suspect he is experiencing stable angina from coronary artery disease. After ruling out other emergent diagnoses, you decide to order non-invasive cardiac testing.

What is stable vs. unstable angina? Angina is the clinical manifestation of coronary artery disease, and results from an imbalance of myocardial oxygen supply and demand. Typically, stable angina will be reproduced on exertion and relieved by rest (or nitroglycerin) in under 30 minutes. Patients may describe the following: pain that is squeezing, constricting, pressing, with or without radiating symptoms; as well as more subtle symptoms such as aching chest pain, nausea, fatigue, dizziness, or light-headedness. Unstable angina will present as new onset severe angina, angina at rest or with minimal activity, or recent increase in frequency and intensity of chronic angina. This patient belongs in your local emergency department.

 What test(s) should I order for my patient? You believe your pre-test probability is intermediate/high for stable angina, so you think a non-invasive cardiac workup is warranted. You ask yourself, which tests do I order? Think about accessibility, yield, and the pros and cons of each test.

Common Non-Invasive Cardiac Tests

A note on ordering a chest x-ray: consider ordering if low-intermediate pre-test probability; useful to assess heart size and pulmonary vasculature, may reveal non cardiac causes of chest pain (3).

Back to the case: You decide to order a routine ECG, chest X-RAY and stress echo to start, as all tests are easily accessible and should yield important diagnostic information. (Note: assessing metabolic risk factors would also be considered in this scenario – e.g. hemoglobin a1c, lipid profile, etc.).

Key Take Home Points:

1. If you have an intermediate/high pre-test probability for stable angina, consider a non-invasive cardiac work up. If you have a very low pre-test probability, avoid cardiac testing and consider alternative differential diagnoses.

2. When in doubt, consult your local cardiologist for recommendations when working someone up with stable angina.

References/Readings

1. Siontis GC, Mavridis D, Greenwood JP, et al. Outcomes of non-invasive diagnostic modalities for the detection of coronary artery disease: network meta-analysis of diagnostic randomised controlled trials. BMJ (Online). 2018;360:k504-k504. doi:10.1136/bmj.k504 (VIEW HERE)

2. Dowsley T, Al-Mallah M, Ananthasubramaniam K, Dwivedi G, McArdle B, Chow BJW. The Role of Noninvasive Imaging in Coronary Artery Disease Detection, Prognosis, and Clinical Decision Making. Canadian journal of cardiology. 2013;29(3):285-296. doi:10.1016/j.cjca.2012.10.022

3. Diagnostic imaging referral guidelines Section E: Cardiovascular (VIEW HERE)

4. Differential diagnoses of chest pain: (VIEW HERE)