When should I consider referring a patient with suspected coronary artery disease for further investigation?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 14 August 2025Updated: 14 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

You should consider referring a patient with suspected coronary artery disease (CAD) for further investigation in several scenarios, depending on the urgency and initial clinical assessment.

  • Emergency Referral (Suspected Acute Coronary Syndrome - ACS):
    • Refer people to hospital as an emergency if they have a recent (confirmed or suspected) ACS and develop further chest pain .
    • If an ACS is suspected, immediate management should begin, and a resting 12-lead ECG should be taken, but these actions should not delay transfer to hospital .
    • Arrange urgent hospital admission if there is any suspicion of a serious cause or concern regarding the patient's general well-being .
    • If the patient is acutely unwell with chest pain and the cause has not been determined, they should be admitted for further assessment .
  • Non-Emergency Diagnostic Investigations:
    • Initial Diagnostic Testing (CT Coronary Angiography): Offer 64-slice (or above) CT coronary angiography if clinical assessment indicates typical or atypical angina . This is also offered if clinical assessment indicates non-anginal chest pain but a 12-lead resting ECG shows ST-T changes or Q waves . When considering diagnostic testing, use clinical judgement and take into account the patient's preferences and comorbidities .
    • Non-Invasive Functional Imaging: Offer non-invasive functional imaging for myocardial ischaemia if 64-slice (or above) CT coronary angiography has shown CAD of uncertain functional significance or is non-diagnostic . For patients with confirmed CAD (e.g., previous myocardial infarction, revascularisation, previous angiography), offer non-invasive functional testing when there is uncertainty about whether chest pain is caused by myocardial ischaemia . An exercise ECG may be used instead of functional imaging in this specific group .
  • Referral for Invasive Coronary Angiography:
    • Offer invasive coronary angiography as a third-line investigation when the results of non-invasive functional imaging are inconclusive .
    • Refer to a cardiologist for angiography (and possible revascularization) if the patient has evidence of extensive ischaemia on ECG, or if angina persists despite optimal drug treatment (maximum therapeutic doses of two drugs) and lifestyle interventions . This decision should be made with the patient, explaining the prognosis without revascularization, the likelihood of left main stem disease or proximal three-vessel disease, and the benefits and risks of the procedure . This discussion is typically undertaken by a practitioner with up-to-date specialist knowledge, usually a cardiologist .
  • ECG Findings:
    • Changes on a resting 12-lead ECG consistent with CAD that may indicate ischaemia or previous infarction include pathological Q waves, left bundle branch block (LBBB), and ST-segment and T wave abnormalities (e.g., flattening or inversion) . These findings should be considered alongside the patient's clinical history and risk factors .

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Educational content only. Always verify information and use clinical judgement.