Master Stable Angina for the USMLE

Patients develop a squeezing, heavy, choking chest pain substernally that occurs with exertion. Pain at rest is unusual for stable angina.

This chest pain is episodic and lasts from 5-15 minutes. Stable angina is typically relieved within 15 minutes.

A 12-lead ECG shows ST segment depression and possibly T wave inversion. This is indicative of myocardial ischemia. It should be noted that the ECG returns to baseline when the pain is relieved.

Nitroglycerin works to vasodilate blood vessels, improving the flow of oxygen and blood to the heart, and relieving the chest pain. It is administered as a fast acting sublingual pill.

This drug can be readministered, and patients can take up to 3 doses, separated by 5 minutes to help relieve chest pain. They should not take more than 3 nitroglycerin tablets over 15 minutes, as this may lead to unsafe blood pressure changes. If chest pain is not relieved in 15 minutes after taking 3 nitroglycerin tablets, emergency medical services should be contacted.

Rest is a relieving factor for patients with stable angina and allows cardiac perfusion to increase.

Antiplatelet drugs, such as aspirin or clopidogrel, may be indicated in patients who have regular anginal episodes. These are used to prevent clot aggregation at sites with profound atherosclerosis, in order to avoid progression to myocardial infarction.

Coronary artery bypass graft (CABG) is a more invasive option in treating angina. It involves bypassing constricted arteries using venous grafts obtained during cardiac surgery in order to provide adequate blood flow to cardiac tissues. Because of long-term patency rates (90% after 10 years), the internal mammary artery (IMA) is the most common artery used for a CABG.

Angioplasty, or mechanically widening the narrowed or obstructed coronary arteries, can be done to help prevent cardiac events. This is typically done using a balloon to widen the artery, and a stent may or may not be placed at the time of angioplasty. This is also called percutaneous coronary intervention (PCI).