What is the difference between stable angina (Angina Pectoris) and unstable angina in terms of chest pain presentation?

From the Guidelines

Stable angina and unstable angina differ significantly in their clinical presentation, with stable angina being predictable and relieved by rest or nitroglycerin, whereas unstable angina is more dangerous, unpredictable, and may not respond to rest or nitroglycerin, often indicating a partially ruptured plaque with forming blood clot that could lead to a complete blockage and heart attack. The key characteristics of stable angina include:

• Predictable chest pain that occurs with exertion or stress
• Reliably improves with rest or nitroglycerin
• Typically lasts 5-15 minutes
• Follows a consistent pattern over time
• Represents a chronic condition where coronary arteries are narrowed but not completely blocked

In contrast, unstable angina is characterized by:

• Unpredictable chest pain that may occur at rest or with minimal exertion
• Lasts longer than 20 minutes
• May not fully resolve with rest or nitroglycerin
• Represents a medical emergency that requires urgent evaluation and treatment to prevent progression to myocardial infarction
• May present as new-onset severe angina or a significant worsening of previously stable symptoms
• Pain quality may be more intense, sharp, or accompanied by additional symptoms like sweating, nausea, or shortness of breath

According to the 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease 1, the initial diagnostic approach to patients who present with symptoms that suggest IHD, such as anginal-type chest pain, should include assessment of cardiovascular risk factors and comorbid conditions that may precipitate "functional" angina. The guideline also emphasizes the importance of distinguishing between stable angina and unstable angina, as the latter requires urgent evaluation and treatment to prevent progression to myocardial infarction.

The European Society of Cardiology's 2013 guidelines on the management of stable coronary artery disease also highlight the importance of careful history-taking and physical examination in diagnosing chest pain, and provide a classification system for chest pain that includes typical angina, atypical angina, and noncardiac chest pain 1.

Overall, the distinction between stable and unstable angina is crucial, as it guides the management and treatment of patients with chest pain, and has significant implications for morbidity, mortality, and quality of life.

From the Research

Difference in Chest Pain: Stable vs Unstable Angina

• The key difference between stable and unstable angina lies in the severity and unpredictability of chest pain, with unstable angina being more severe and unpredictable 2.
• Unstable angina is a condition where the blood flow to the heart is suddenly reduced, causing chest pain that is often more severe and prolonged than stable angina 3, 4.
• Stable angina, on the other hand, is a condition where the blood flow to the heart is reduced, but the chest pain is predictable and usually occurs with physical activity or stress 2.
• The treatment for unstable angina typically involves a combination of medications, including antiplatelet agents, anticoagulants, and nitrates, as well as possible invasive procedures such as angioplasty or coronary artery bypass grafting 3, 4, 5.
• In contrast, stable angina is often managed with lifestyle modifications, such as regular exercise and a healthy diet, as well as medications to control symptoms and prevent further progression of the disease 5, 2.
• Studies have shown that patients with unstable angina have a higher risk of adverse outcomes, including myocardial infarction and death, compared to those with stable angina 3, 4.
• The use of antiplatelet agents, such as aspirin and clopidogrel, has been shown to be effective in reducing the risk of adverse outcomes in patients with unstable angina 3, 4, 6.
• Additionally, the use of glycoprotein IIb/IIIa antagonists has been shown to be effective in reducing the risk of adverse outcomes in patients with unstable angina, particularly those undergoing invasive procedures 3, 6.