Angina Classification and Management

Introduction to Angina Types

The American College of Cardiology and other guideline societies classify angina into five major types: stable angina, unstable angina, variant (Prinzmetal's) angina, atypical angina, and microvascular angina (Syndrome X), each with distinct clinical presentations and prognostic implications that guide management decisions 1, 2, 3

Stable angina is characterized by predictable chest discomfort that occurs with exertion or emotional stress, has not changed in frequency or pattern for at least 6 weeks, and is consistently relieved by rest and/or nitroglycerin, with severity graded using the Canadian Cardiovascular Society (CCS) classification system 1, 2, 4
The discomfort is typically retrosternal, described as pressure or heaviness, and may radiate to the left arm, neck, or jaw 5
Episodes are triggered by increased myocardial oxygen demand (physical activity, emotional stress) and resolve within minutes of rest 1

Unstable angina represents a critical phase of coronary disease with three defining presentations: rest angina lasting ≥20 minutes, new-onset severe angina (CCS Class III or IV), or crescendo angina with recent acceleration in severity, requiring urgent evaluation 1, 2, 7
Unlike stable angina, symptoms occur unpredictably at rest or with minimal exertion 7
Compared to NSTEMI patients, those with unstable angina have lower mortality risk but still face substantial morbidity 5, 7

Variant angina is caused by coronary artery vasospasm, typically occurs spontaneously at rest (not with exertion), and is characterized by transient ST-segment elevation during episodes 3

Atypical angina refers to chest discomfort that is possibly consistent with myocardial ischemia but lacks the classic characteristics of typical angina pectoris, with symptoms including epigastric pain, indigestion-like complaints, or isolated dyspnea without classic chest pressure 6, 1, 3
This presentation is more common in elderly patients, women, and those with diabetes, chronic kidney disease, or dementia 5

Microvascular angina (Syndrome X) is defined by the triad of typical exercise-induced angina, positive stress testing, and angiographically normal coronary arteries, caused by coronary microvascular dysfunction 8
Patients experience frequent anginal episodes (often several times per week) with both exertional and resting chest pain 8
This condition is frequently encountered in patients with hypertension, with or without left ventricular hypertrophy 8

Noncardiac chest pain represents discomfort that is inconsistent with myocardial ischemia and requires consideration of alternative diagnoses including gastrointestinal, pulmonary, or musculoskeletal causes 6, 3
Differential diagnoses include esophageal spasm, gastric ulcer, cholecystitis, pancreatitis, pulmonary embolism, pericarditis, and aortic dissection 5, 9

When evaluating chest pain, the American Heart Association recommends following a sequence that includes determining stability, assessing timing and triggers, evaluating response to testing, and identifying high-risk features 1, 7
The European Society of Cardiology suggests that relief of symptoms with nitroglycerin is not specific for angina, as it occurs with other causes of chest pain including esophageal disorders 9