Diagnostics

Initial evaluation

• Clinical evaluation

  • Determine the pretest probability of CAD.

  • Identify traditional ASCVD risk factors.

  • Determine the nature and frequency of angina episodes.

  • Physical examination may be normal; look for:

    • Clinical features of peripheral vascular disease

    • Clinical features of heart failure

    • Features of valvular heart diseases

• Resting ECG: indicated for all patients

Additional evaluation [13]

Perform the following according to the pretest probability of CAD: [14]

• Obvious noncardiac cause : No cardiac testing required

• Low PTP of obstructive CAD

  • Additional diagnostic testing is not routinely recommended.

  • CAC scoring or cardiac exercise stress testing may be considered in select cases.

• Intermediate to high PTP of obstructive CAD

  • Coronary CT angiography (CCTA)

  • OR cardiac stress testing

    • Patients able to exercise: Exercise stress testing is preferred.

      • Interpretable ECG: Obtain exercise ECG testing or exercise stress imaging.

      • Uninterpretable ECG: Obtain exercise stress imaging.

    • Patient unable to exercise: Pharmacological stress testing (i.e. with imaging) is appropriate.

• Best initial test for chest pain

• Usually normal in stable angina

• Findings that suggest previous MI or unstable angina: These typically necessitate further workup (see “Acute coronary syndrome”).

  • ST-segment depression

  • T-wave inversion or T-wave flattening

  • Wellens pattern

• Uninterpretable ECG: one that does not allow identification of stress-induced ischemic changes, typically due to preexisting abnormalities that affect interpretability, such as

  • LBBB

  • Ventricular paced rhythm

Resting ECG results are usually normal in patients with stable CAD.

• Noninvasive testing

  • Provocative: cardiac stress testing

    • Exercise stress testing

      • Exercise ECG testing

      • Exercise stress imaging: e.g., echocardiography, myocardial perfusion scan, cardiac MRI (CMR)

    • Pharmacological stress testing: cardiac imaging (e.g., echocardiography, myocardial perfusion scan, CMR) combined with pharmacological stressor (e.g., dobutamine) under ECG monitoring

  • Nonprovocative: cardiac anatomic testing, e.g., CCTA, CAC scoring

• Invasive testing: coronary angiography

Description

• The goal is to detect evidence of stress-induced ischemia.

• Heart rate is monitored throughout the study [19]

  • Estimated maximum heart rate = 220 – age (in years)

  • Target heart rate = 85% of the maximum heart rate

• 12-lead ECG is used for monitoring throughout the study.

Indications [20]

• Chronic stable angina

• Provocation of arrhythmia

• Evaluation of patients who experience other exertional symptoms (e.g., palpitations, syncope)

• Risk assessment for patients who are due to undergo cardiac revascularization

Types of stress induction

• Exercise stress tests (e.g., treadmill or bicycle): first-line [14][18]

• Pharmacological stress tests (e.g., vasodilator or inotropic medication): alternative in patients unable to exercise [1]

Some clinical and ECG criteria vary between exercise stress tests and pharmacological stress tests (see “Comparison of cardiac stress tests” for details). General criteria include the following:

• A diagnostic endpoint is reached (preferred). [14][19][20]

• A target heart rate threshold is achieved (i.e., if no diagnostic endpoint is reached)

• Significant cardiac arrhythmia

• Hold methylxanthines (e.g., caffeine, aminophylline) for 12 hours prior to testing (no need to hold for dobutamine testing).

• Hold dipyridamole for 48 hours prior to adenosine and regadenoson stress tests.

• Beta blockers, CCBs, and nitrates can affect diagnostic value and may be held prior to testing at the treating clinician's discretion. [20]

• Coronary CT angiography (CCTA): can visualize anatomic CAD [21]

• Coronary artery calcium (CAC) scoring: measures the amount of calcification in the coronary arteries

• Indications

  • Chronic stable angina

    • Contraindications for or inability to perform noninvasive testing

    • High clinical suspicion for CAD and ambiguous results on noninvasive testing

    • Abnormal results from noninvasive testing

    • Persistent symptoms of angina despite appropriate therapy

  • Other indications: e.g., acute coronary syndrome and certain valvular diseases (see “Cardiac catheterization”)

• Uses

  • Direct visualization of coronary arteries

  • To determine the feasibility of direct therapeutic intervention using percutaneous coronary intervention (see “Treatment” below)

  • Cardiac catheterization can provide information on several parameters (e.g., coronary blood flow, pressure within heart chambers, cardiac output, oxygen saturation). [25]

• Supportive findings: [12]

  • The extent of the disease is reported as either the number of involved vessels (1, 2, or 3 vessels) or involvement of the left main coronary artery (LMCA).

  • Significant coronary artery stenosis is usually defined as one of the following:

    • ≥ 50% narrowing of the LMCA

    • ≥ 70% narrowing of other coronary arteries, e.g., RCA, LCx, LAD

Patients with acute chest pain and other concerning clinical findings (e.g., hypotension) or ECG changes that are suggestive of acute coronary syndrome (e.g., new heart blocks or arrhythmias) should undergo cardiac catheterization.