What is the classification and management of angina?

Angina Classification and Management

The Canadian Cardiovascular Society (CCS) classification system is the standard for grading angina severity, with four classes based on physical activity limitations, while management should be tailored to both symptom severity and underlying coronary disease.

Classification of Angina

Stable Angina Classification (CCS)

The Canadian Cardiovascular Society classification system grades angina based on the level of physical activity that precipitates symptoms:

• Class I: Ordinary physical activity (walking, climbing stairs) does not cause angina. Angina occurs with strenuous, rapid, or prolonged exertion at work or recreation 1

• Class II: Slight limitation of ordinary activity. Angina occurs when walking/climbing stairs rapidly, walking uphill, walking after meals, in cold weather, under emotional stress, or only during the few hours after awakening. Angina occurs when walking more than two blocks on level ground or climbing more than one flight of ordinary stairs at normal pace 1

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

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

Unstable Angina Classification

Unstable angina has three principal presentations:

• Rest angina: Angina occurring at rest and prolonged, usually greater than 20 minutes 1

• New-onset angina: New-onset angina of at least CCS class III severity 1

• Increasing angina: Previously diagnosed angina that has become distinctly more frequent, longer in duration, or lower in threshold (increased by 1 or more CCS class to at least CCS class III severity) 1

Prognostic Significance

• Higher CCS classes (III and IV) are associated with increased all-cause mortality (hazard ratios 1.33 and 1.48 respectively, compared to CCS class I) 2

• CCS class IV is associated with higher rates of hospitalization, percutaneous coronary intervention (hazard ratio 1.92), and coronary artery bypass grafting (hazard ratio 2.51) 2

• Patients with CCS class III and IV have significantly fewer normal coronary angiograms, indicating more severe coronary disease 3

Management of Angina

Pharmacological Management

1. First-line medications:

   • Beta-blockers (e.g., metoprolol) - reduce heart rate, blood pressure, and myocardial contractility, thereby decreasing myocardial oxygen demand 4
   • Nitrates - cause vasodilation, reducing preload and afterload 1

2. Second-line medications:

   • Calcium channel blockers - particularly useful when beta-blockers are contraindicated 1
   • Ranolazine - for patients with persistent symptoms despite other therapies 1

3. Important considerations for beta-blocker therapy:

   • Do not abruptly discontinue in patients with coronary artery disease due to risk of severe angina exacerbation, MI, or ventricular arrhythmias 4
   • When discontinuing, gradually reduce dose over 1-2 weeks 4
   • Use with caution in patients with heart failure, as beta-blockers can cause depression of myocardial contractility 4

Risk Factor Modification

• Primary care providers should evaluate major risk factors for coronary heart disease at regular intervals (approximately every 3-5 years) 1

• Patients with established coronary heart disease should receive intensive risk factor intervention, including:

  • Smoking cessation
  • Blood pressure control
  • Lipid management
  • Diabetes management
  • Weight management
  • Physical activity 1

Revascularization

Indications for revascularization based on symptom severity and coronary anatomy:

• Percutaneous Coronary Intervention (PCI):

  • Indicated for patients with CCS class I-IV angina despite medical therapy with single-vessel disease 1
  • Also indicated for multi-vessel disease with objective evidence of large ischemia 1

• Coronary Artery Bypass Grafting (CABG):

  • Indicated for left main stem disease, three-vessel disease with objective large ischemia, three-vessel disease with poor ventricular function, or two/three-vessel disease including severe disease of the proximal LAD 1
  • Preferred over PCI in diabetic patients with multi-vessel disease 1

Management Algorithm Based on CCS Class

1. CCS Class I:

   • Optimize medical therapy with beta-blockers and/or nitrates 4
   • Aggressive risk factor modification 1
   • Consider stress testing for risk stratification 1

2. CCS Class II:

   • Intensify medical therapy 1
   • Consider non-invasive testing for ischemia 1
   • Consider revascularization if symptoms persist despite optimal medical therapy 1

3. CCS Class III-IV:

   • Prompt coronary angiography 1
   • Revascularization (PCI or CABG) based on coronary anatomy 1
   • Optimize medical therapy while awaiting revascularization 1

4. Unstable Angina:

   • Immediate hospitalization 1
   • Intensive medical therapy 1
   • Early invasive strategy with coronary angiography 1

Special Considerations

• Refractory angina: For patients not suitable for revascularization with persistent symptoms despite optimal medical therapy, novel therapies such as coronary sinus reducing devices may be considered 5

• Microvascular angina: Patients may have typical angina symptoms with non-obstructed coronary arteries. Consider assessment for endothelial dysfunction 1

• Vasospastic angina: May require calcium channel blockers as primary therapy rather than beta-blockers 1