Applications of nuclear cardiology in known stable coronary artery disease

Applications of Nuclear Cardiology in Known Stable Coronary Artery Disease Stable coronary artery disease (CAD) refers to non-acute presentations related to a mismatch of demand and supply of the myocardial blood flow, commonly presenting with symptoms of angina. In patients with an established diagnosis of CAD, objectives of testing are to establish if new or worsening symptoms are due to progression of the disease, identify those at a high future cardiac risk, and decide if there is a need for revascularization or uptitration of medical therapy. In this chapter, we compare the advantages and limitations of various non-invasive imaging modalities available to evaluate these patients. We discuss the indications of and the literature supporting the use of radionuclide myocardial perfusion imaging, which has a key role in evaluation of these patients. MPI is generally inappropriate for asymptomatic patients with known CAD, unless those otherwise at a high risk for flow-limiting CAD, such as those with elevated calcium scores or after a period of 2 and 5 years post PCI and CABG respectively, when prognostically important silent ischemia may be present. Exercise stress is preferred for patients who can exercise to a diagnostic workload. PET if available is preferred in those who need pharmacologic stress, and should be considered in patients where SPECT image quality may be hampered, and high risk patients who may have more extensive disease. Quantitative myocardial blood flow measurements with PET can detect high risk CAD phenotypes of diffuse atherosclerosis and microvascular dysfunction in addition to obstructive epicardial CAD. We also discuss how MPI results can help identify optimal candidates for revascularization.