How is coronary artery disease diagnosed?

Diagnosis of Coronary Artery Disease

The diagnosis of coronary artery disease requires a combination of clinical evaluation, non-invasive functional imaging for myocardial ischemia, or coronary CT angiography (CTA) as the initial diagnostic tests in symptomatic patients where obstructive CAD cannot be excluded by clinical assessment alone. 1

Clinical Assessment

Symptoms and Signs

• Angina characteristics (cornerstone of diagnosis):

  • Location: Typically chest discomfort near sternum; may radiate to epigastrium, jaw, teeth, between shoulder blades, or either arm
  • Character: Pressure, tightness, heaviness; sometimes strangling, constricting or burning
  • Duration: Brief (usually <10 minutes)
  • Relationship to exertion: Appears or worsens with increased exertion, rapidly improves with rest 1

• Atypical presentations:

  • Shortness of breath (may be the sole symptom)
  • Fatigue, faintness, nausea, restlessness
  • Symptoms after heavy meals or upon waking 1
  • Response to nitrates (rapid relief with sublingual nitrates)

Risk Factor Assessment

• Hypertension, hypercholesterolemia, diabetes
• Smoking, sedentary lifestyle, obesity
• Family history of premature CVD 1

Diagnostic Testing Algorithm

Initial Non-Invasive Testing

1. 12-lead ECG: Recommended for all patients to establish baseline and identify silent ischemic changes 2

2. Non-invasive functional imaging OR coronary CTA:

   • Selection based on clinical likelihood of CAD, patient characteristics, local expertise, and test availability 1

   • Functional imaging options:

     • Stress echocardiography
     • Nuclear myocardial perfusion imaging
     • Stress cardiac MRI

   • Coronary CTA considerations:

     • Not recommended with extensive coronary calcification, irregular heart rate, obesity, or inability to cooperate with breath-hold 1
     • Functional imaging recommended if CTA shows CAD of uncertain functional significance 1

3. Resting echocardiography: Recommended to quantify left ventricular function in all patients with suspected CAD 1

4. Laboratory testing:

   • Lipid profile, fasting glucose/HbA1c
   • Renal function
   • High-sensitivity cardiac troponin 2

Advanced Testing

1. Invasive coronary angiography (ICA) recommended when:

   • High clinical likelihood with severe symptoms refractory to medical therapy
   • Typical angina at low exercise level with high event risk on clinical evaluation 1
   • Significant worsening of symptoms with high-risk clinical profile 1

2. Invasive functional assessment (FFR/iwFR):

   • Must be available to evaluate stenoses before revascularization (unless >90% diameter stenosis) 1
   • Recommended for risk stratification in symptomatic patients with severe CAD 1

Special Considerations

Vasospastic Angina

• ECG during angina episode if possible
• Invasive angiography or coronary CTA recommended for patients with characteristic episodic resting angina and ST-segment changes that resolve with nitrates/calcium antagonists 1

Common Diagnostic Pitfalls

1. Overreliance on symptoms alone: While history is crucial, objective tests are necessary to confirm diagnosis and assess severity 1

2. Focusing only on obstructive lesions: Non-obstructive plaques may also cause acute coronary syndromes 3

3. Inappropriate use of coronary calcium scoring:

   • Not recommended to identify individuals with obstructive CAD 1
   • Not recommended as routine follow-up test 1

4. Using invasive angiography solely for risk stratification: Not recommended without appropriate clinical indications 1

5. Underestimating risk in asymptomatic patients with severe coronary calcifications 2

Risk Stratification After Diagnosis

• Based on clinical assessment and results of initial diagnostic tests 1
• Preferably using stress imaging or coronary CTA
• Consider invasive angiography with physiological guidance (FFR) for patients with high-risk profiles 1

By following this diagnostic approach, clinicians can effectively identify CAD, assess its severity, and guide appropriate management strategies to reduce morbidity and mortality associated with this condition.