Coronary artery disease: Clinical sciences

Coronary artery disease, or CAD, is caused by atherosclerosis of the coronary arteries, which occurs when plaque builds up in the vessels, eventually narrowing the lumen, and causing a mismatch between oxygen supply and demand of the heart. Over time, reduced oxygen supply can lead to myocardial ischemia or even infarction.

The diagnosis of CAD is based on atherosclerotic risk factors that categorize patients into low, intermediate, or high risk groups based on their probability for obstructive disease.

Now, if you suspect CAD, first perform an ABCDE assessment. This is to determine if the patient is unstable or stable.

If unstable, stabilize their airway, breathing, and circulation. Next, obtain IV access, provide supplemental oxygen, and put them on continuous vital sign monitoring including blood pressure, heart rate, and pulse oximetry.

At this point, you should suspect CAD with acute coronary syndrome, which includes unstable angina, non-ST elevated myocardial infarction, or NSTEMI, or ST-elevated myocardial infarction, or STEMI.

Once you stabilize the patient, obtain a focused history and physical examination, and order serial troponin levels and an ECG.

Okay, let’s focus on unstable angina, your patient may report sudden chest discomfort that doesn’t improve with rest, and feelings of uneasiness or “impending doom”.

Other common symptoms include dizziness, shortness of breath, sweating, as well as nausea.

Physical exam typically reveals a distressed, anxious, and diaphoretic individual.

Ok, next take a look at the serial troponins. If there’s no myocardial infarction, troponins will typically be normal.

While ECG may or may not show signs of ischemia like ST segment depression or new T wave inversion.

This combination of history, physical exam, labs, and ECG findings are characteristic of unstable angina, where chest pain is caused by an insufficient supply of oxygen to the cardiac tissue.