Current international guidelines for the investigation of patients with suspected coronary artery disease

Patients suspected of having coronary artery disease (CAD) who present with new onset chest pain can be investigated by numerous diagnostic modalities. National and international guidelines have been drawn up to assist cardiologists in selecting the most appropriate investigation(s). Here, we summarize and compare three current guidelines and discuss the differences between them. The UK National Institute for Health and Care Excellence (NICE) published its guidelines in 2010.1 The guidelines recommend that patients are categorized into ‘low’ or ‘high’ risk of CAD groups, depending on whether they have a cardiovascular risk factor (diabetes, smoking, and hyperlipidaemia). Patients are assigned a pre-test probability (PTP) score of having CAD based on risk category, age, gender, and typicality of chest pain. The guidance then suggests that patients with a PTP of <10% should not be investigated further. Patients with a PTP of 10–29% are recommended to undergo computed tomography (CT) calcium scoring. A zero calcium score is taken as confirmation of very low likelihood of CAD and no further testing is suggested. If the calcium score is above zero, it is recommended to proceed to a CT coronary angiogram (CTCA). If there is extensive calcification (calcium score of >400), a functional imaging test or invasive coronary angiography (ICA) is recommended. Patients with an intermediate PTP of 30–60% are recommended to have a functional imaging test; i.e. myocardial perfusion scintigraphy (MPS), stress echocardiography, or stress cardiac magnetic resonance imaging. Patients with a high PTP of 61–90% are recommended to undergo ICA, and patients with a PTP of >90% are assumed to have CAD without requiring further testing to make the diagnosis. The assessment of prognosis and management of patients diagnosed as having stable angina is covered in a separate guideline, which emphasizes the importance of secondary prevention and optimal medical therapy.2 According to this guideline, revascularization should be considered in all patients with confirmed significant CAD, particularly if they have ongoing symptoms on optimal medical therapy, on the basis of an informed discussion about the potential additional benefit.2