What tests are used to diagnose patients at risk of coronary artery disease (CAD)?

Diagnostic Tests for Patients at Risk of Coronary Artery Disease

The most effective initial diagnostic approach for patients at risk of coronary artery disease (CAD) is non-invasive functional imaging for myocardial ischemia or coronary computed tomography angiography (CCTA), as these tests provide the highest diagnostic accuracy for detecting obstructive CAD in symptomatic patients. 1

Initial Risk Assessment

• Risk assessment should begin with estimating the probability of CAD based on patient age, sex, cardiovascular risk factors, and pain characteristics 1
• Assessment of cardiovascular risk factors should include:
  • Smoking history
  • Hyperlipidemia
  • Diabetes mellitus (particularly important risk factor)
  • Hypertension
  • Family history of premature CAD
  • Postmenopausal status in women 1
• Clinical risk assessment tools such as the Diamond-Forrester method, Framingham risk score, coronary calcium score (CCS), or Duke Clinical Score can be used to categorize patients as low, medium, or high risk 1

Basic Initial Tests

• Resting 12-lead ECG is recommended for all patients with chest pain without obvious non-cardiac cause 1
• Resting transthoracic echocardiogram is recommended for:
  • Exclusion of alternative causes of angina
  • Identification of regional wall motion abnormalities suggestive of CAD
  • Measurement of left ventricular ejection fraction for risk stratification
  • Evaluation of diastolic function 1
• Chest X-ray is recommended for patients with atypical presentation, signs/symptoms of heart failure, or suspected pulmonary disease 1
• Laboratory assessment should include lipid profile and screening for diabetes mellitus (HbA1c and fasting plasma glucose) 1

Advanced Diagnostic Testing Based on Pre-test Probability

For Low to Moderate Pre-test Probability (>5%-50%)

• CCTA is recommended as the preferred initial diagnostic test to rule out obstructive CAD 1
• CCTA is not recommended when extensive coronary calcification, irregular heart rate, significant obesity, or inability to cooperate with breath-hold commands is present 1
• Coronary calcium detection by computed tomography alone is not recommended to identify individuals with obstructive CAD 1

For Moderate to High Pre-test Probability (>15%-85%)

• Stress imaging tests are recommended:
  • Single-photon emission computed tomography (SPECT) or positron emission tomography (PET) myocardial perfusion imaging to diagnose and quantify myocardial ischemia/scar 1
  • Cardiac magnetic resonance (CMR) perfusion imaging to diagnose and quantify myocardial ischemia/scar 1
  • Stress echocardiography with myocardial perfusion using contrast agents to improve diagnostic accuracy 1

For Very High Pre-test Probability (>85%)

• Invasive coronary angiography (ICA) is recommended to diagnose CAD in patients with:
  • Very high clinical likelihood of disease
  • Severe symptoms refractory to guideline-directed medical therapy
  • Angina at a low level of exercise
  • High event risk 1

Important Considerations

• Selection of the initial non-invasive diagnostic test should be based on pre-test likelihood of CAD, patient characteristics, local expertise, and test availability 1
• Functional imaging for myocardial ischemia is recommended if CCTA has shown CAD of uncertain functional significance or is not diagnostic 1
• When ICA is performed, it is recommended to have coronary pressure assessment available (FFR/iFR) to evaluate functional severity of intermediate stenoses 1
• Exercise ECG is useful for assessing exercise tolerance, symptoms, arrhythmias, blood pressure response, and event risk in selected patients, but has limitations in diagnostic accuracy 1
• Ambulatory ECG monitoring is recommended only in patients with chest pain and suspected arrhythmias, not as a routine examination 1

Common Pitfalls to Avoid

• Relying solely on coronary calcium detection by computed tomography to identify individuals with obstructive CAD 1
• Using ST-segment alterations recorded during supraventricular tachyarrhythmias as evidence of CAD 1
• Performing ICA solely for risk stratification without clinical indications 1
• Using routine ambulatory ECG monitoring in patients with suspected CAD 1
• Failing to perform invasive functional assessment (FFR/iFR) to evaluate stenoses before revascularization, unless very high-grade (>90% diameter stenosis) 1

By following this evidence-based diagnostic approach, clinicians can effectively identify patients with CAD and initiate appropriate management strategies to reduce morbidity and mortality.