Diagnostic Testing for Suspected Angina

Patient Selection and Testing Criteria

The American College of Cardiology and European Society of Cardiology recommend exercise stress testing for patients with suspected angina who have an intermediate to high probability of coronary artery disease, as this is essential for risk stratification to determine subsequent coronary events and mortality risk 1, 2
The European Society of Cardiology specifically recommends exercise ECG for patients with pre-test probability of 15-65%, while stress imaging is preferred for those with 66-85% probability or reduced left ventricular ejection fraction 4, 5
Exercise ECG using the Bruce protocol with Duke treadmill score should be the initial test for patients with suspected chronic stable angina who have a normal or near-normal resting ECG, are not taking digoxin, and have an intermediate to high probability of CAD (15-85% pre-test probability) 1, 2, 4, 5

Exercise ECG testing is contraindicated or non-diagnostic in patients with Wolff-Parkinson-White syndrome, electronically paced ventricular rhythm, complete left bundle-branch block, more than 1 mm ST depression at rest, or those taking digoxin 1, 2, 4
For these patients, pharmacologic stress imaging (echocardiography, SPECT, PET, or CMR) should be used as the initial test 2, 5

The Duke treadmill score provides critical prognostic information that directly impacts mortality, with a low risk score (≥5) indicating 4-year survival of 99% (0.25% annual mortality) and a high risk score (≤-10) indicating 4-year survival of 79% (5% annual mortality) 1, 2, 3
The formula for the Duke treadmill score is: Exercise time (minutes) − (5 × ST deviation in mm) − (4 if angina occurs) − (8 if angina causes test termination) 1, 3

For patients with low-intermediate pre-test probability (15-50%), coronary CTA may be considered as an alternative to ischemia testing, provided adequate technology and local expertise are available 4, 5
Stress imaging (echocardiography or nuclear perfusion) is recommended for patients with abnormal resting ECG, prior coronary revascularization, inability to exercise adequately, or women (though standard exercise ECG remains acceptable as initial test) 2, 3, 5, 6

The European Society of Cardiology recommends against ordering stress testing in truly low-risk patients (pre-test probability <15%), as this leads to false-positive results and unnecessary downstream testing 4, 5
The American College of Cardiology recommends against repeating stress testing within 3 years in patients without change in clinical status, and against delaying angiography by ordering stress testing in patients with high-risk clinical features (severe symptoms, prior positive stress test, known multivessel disease) 6
Exercise stress testing is more useful for ruling out CAD than confirming it, with a negative test in appropriate patients having excellent negative predictive value (annual cardiac event rate 0.9%) 1