THE CONTEXT
Risk assessment in stable angina combines symptoms, associated illness, coronary anatomy and ventricular function. Imaging establishes coronary disease and helps guide further treatment.
Higher-risk and lower-risk findings
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Recent-onset symptoms lasting less than 6 months are higher risk; long-standing symptoms are lower risk.
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Canadian Cardiovascular Society class II–IV symptoms are higher risk, whereas class I symptoms are lower risk.
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Diabetes mellitus and comorbidity are listed among higher-risk findings.
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Post-infarct angina is higher risk, whereas predictable exertional angina is lower risk.
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Ischaemia at low workload is higher risk; ischaemia occurring only at high workload is lower risk.
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Left main or three-vessel disease is higher risk; single-vessel or two-vessel disease is lower risk.
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Poor left ventricular function is higher risk, whereas good left ventricular function is lower risk. Patients may fall between the two risk categories.
CT coronary angiography
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CT coronary angiography is the first-choice non-invasive imaging investigation for diagnosing coronary artery disease.
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It clarifies the diagnosis and guides preventative and anti-anginal treatment.
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It helps reduce invasive catheterisation in patients with normal coronary arteries and directs it towards patients with significant disease.
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Its use is associated with a marked reduction in future MI risk, likely through better-targeted preventative interventions for previously unrecognised disease.
Functional imaging in known coronary disease
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Myocardial perfusion scanning or stress echocardiography is indicated when the relationship between symptoms and myocardial ischaemia is uncertain.
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A perfusion defect present during stress but absent at rest indicates reversible myocardial ischaemia.
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A persistent perfusion defect during both stress and rest usually indicates previous MI.
Invasive coronary angiography
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Coronary angiography provides detailed anatomical information about the extent of coronary luminal obstruction.
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It is usually performed when coronary artery bypass graft surgery or percutaneous coronary intervention is being considered.