What is chronic stable angina?

Definition of Chronic Stable Angina

Chronic stable angina is a clinical syndrome characterized by discomfort in the chest, jaw, shoulder, back, or arm that is typically aggravated by exertion or emotional stress, lasts for several minutes, and is relieved by rest and/or nitroglycerin. 1

Key Characteristics

Chronic stable angina is distinguished by several specific features:

• Location: Typically substernal chest discomfort, but may be felt anywhere from the epigastrium to the lower jaw or teeth, between the shoulder blades, or in either arm to the wrist and fingers 1

• Character: Often described as pressure, tightness, heaviness, strangling, constricting, or burning sensation 1

• Duration: Brief episodes, usually lasting less than 10 minutes, and commonly even less 1

• Precipitating factors:

  • Typically triggered by physical exertion (walking up an incline, against a breeze, in cold weather)
  • Emotional stress
  • Heavy meals
  • Cold exposure 1

• Relieving factors:

  • Rest
  • Sublingual nitroglycerin (typically within minutes) 1

Classification of Angina Severity

The Canadian Cardiovascular Society (CCS) classifies angina severity into four grades:

• Class I: Ordinary physical activity (walking, climbing stairs) does not cause angina. Angina occurs with strenuous, rapid, or prolonged exertion.

• Class II: Slight limitation of ordinary activity. Angina occurs when walking or climbing stairs rapidly, walking uphill, walking after meals, in cold/wind, under emotional stress, or during the few hours after awakening.

• Class III: Marked limitation of ordinary physical activity. Angina occurs when walking 1-2 blocks on level ground or climbing one flight of stairs at normal pace.

• Class IV: Inability to perform any physical activity without discomfort—anginal symptoms may be present at rest. 1

Distinguishing Features from Other Types of Angina

Chronic stable angina must be differentiated from:

1. Unstable angina: Defined as angina that presents in one of three ways:

   • Rest angina
   • Severe new-onset angina
   • Increasing angina (crescendo pattern) 1, 2

2. Variant (Prinzmetal) angina: Occurs spontaneously, usually at rest, and is frequently associated with transient ST-segment elevation 1

3. Microvascular angina: May present with typical angina symptoms but in the setting of non-obstructive coronary artery disease 3

Clinical Significance and Prognosis

Chronic stable angina represents a significant cause of morbidity that impacts quality of life 4. The prognosis for patients with isolated stable angina (without prior cardiovascular events) includes:

• Annual mortality rate of approximately 1.4 per 100 patient-years
• Combined rate of death or cardiac events of 8.7 per 100 patient-years 5

Important Considerations for Diagnosis

• A careful history remains the cornerstone of diagnosis 1
• Chest pain can be classified as typical angina, atypical angina, or non-cardiac chest pain based on characteristics 1
• Patients with chronic stable angina should not have had an acute myocardial infarction or revascularization procedure in the previous 6 months 1

Management Implications

Proper identification of chronic stable angina is crucial for appropriate management, which may include:

• First-line medications: beta-blockers, calcium channel blockers, and short-acting nitrates 6, 7
• Second-line medications: ranolazine, ivabradine, nicorandil, and trimetazidine (availability varies by country) 8, 7
• Consideration of revascularization in certain high-risk individuals 4

Understanding the precise definition and characteristics of chronic stable angina is essential for accurate diagnosis and effective management to improve patient outcomes and quality of life.