Diagnostic Approach to Coronary Artery Disease

Initial Evaluation and Testing

The European Society of Cardiology recommends exercise stress testing as the initial test for diagnosing coronary artery disease in patients with intermediate pre-test probability who have a normal resting ECG, can exercise adequately, and are not taking medications that interfere with ECG interpretation 1, 2
Exercise stress testing is useful for evaluating control of symptoms and ischemia in patients already on treatment, providing valuable information beyond ECG changes, including workload achieved, heart rate response, blood pressure response, and symptoms 1, 2

The European Society of Cardiology recommends stress MIBI as the initial test when pre-test probability is high (66-85%) or LVEF <50% in patients without typical angina, and for patients with abnormal resting ECG that prevents accurate interpretation of ECG changes during stress 1, 3
Stress MIBI is indicated for patients who have had prior revascularization (PCI or CABG) with a significant change in anginal pattern, and for assessing functional severity of intermediate lesions on coronary angiography 1, 3, 4, 5
Stress MIBI is superior to exercise ECG in diagnostic performance, with the ability to quantify and localize areas of ischemia 2, 6

The American College of Cardiology recommends pharmacologic stress perfusion imaging (dipyridamole/adenosine) for patients unable to exercise adequately, and as the first-line pharmacological stress test for patients with left bundle-branch block (LBBB) or electronically paced ventricular rhythm, regardless of ability to exercise 7, 4, 2

The American College of Cardiology recommends coronary angiography after non-invasive testing has suggested significant CAD that may benefit from revascularization, and when stress imaging tests show high-risk features despite a normal exercise ECG 4, 8
Coronary angiography is indicated when non-invasive test results are equivocal or conflicting with clinical presentation, and may be considered first-line in patients with high pre-test probability and severe, typical symptoms 1, 3, 8

For patients with LBBB or paced rhythm, pharmacologic stress perfusion imaging (dipyridamole/adenosine) is preferred, while exercise or dobutamine stress imaging is not recommended 7, 4
For patients with LVH, stress nuclear techniques have similar diagnostic sensitivity and specificity as in patients without LVH 7
For women, exercise ECG is less sensitive and specific, but a randomized trial showed no incremental benefit of initial MPI over standard exercise testing in women with preserved functional capacity 1
For elderly patients, perfusion scintigraphy has demonstrated prognostic value 7

The American Heart Association recommends exercise stress SPECT as the preferred choice for patients capable of adequate exercise (≥5 METs), as it provides superior physiological stress and powerful independent prognostic information from exercise capacity alone 9, 10
Exercise testing should be selected over pharmacological stress when patients can perform routine activities of daily living without difficulty, as exercise often achieves higher physiological stress than pharmacological agents, translating into superior ischemia detection 9
The ability to exercise provides critical prognostic data—exercise capacity alone is one of the strongest predictors of mortality, independent of imaging findings, with a strength of evidence considered high 11

Exercise SPECT has a sensitivity of 85-90% and specificity of 70-75%, while adenosine SPECT has a sensitivity of 83-94% and specificity of 64-90% 12, 13
Pharmacological stress perfusion imaging (adenosine or dipyridamole) is the preferred first-line approach in patients with left bundle branch block (LBBB) or ventricular paced rhythm, as it provides superior diagnostic accuracy and risk stratification 14
Patients who are unable to exercise adequately, such as those with physical limitations or severe deconditioning, should undergo pharmacological stress SPECT 9, 12, 13

For symptomatic women with intermediate risk who can exercise ≥5 METs with normal resting ECG, exercise SPECT is recommended as the initial test, according to the American College of Cardiology 10
In elderly patients, exercise capacity remains a powerful prognostic indicator, and exercise stress testing should be used when feasible rather than defaulting to pharmacological stress based on age alone, as recommended by the American Heart Association 11
A stepwise approach to selecting the appropriate stress test includes assessing exercise capacity, checking for LBBB or ventricular pacing, and verifying the absence of disabling comorbidities, with the goal of maximizing prognostic value and diagnostic accuracy 9, 14, 12, 13