Stable chest pain — suspected coronary artery disease

NICE CG95 (2016 update); ESC 2024 chronic coronary syndromes

Anatomical imaging of the coronary arteries has become the first test for new stable chest pain in most systems. Almost every vetting decision here is about whether the patient can be prepared to give a diagnostic study: heart rate, rhythm, breath-hold and nitrate tolerance.

New or worsening chest pain of suspected cardiac origin in a patient without known coronary disease, referred from a chest pain clinic or from primary care.

Referenced decision support — confirm against your local protocol.

Decision support, not a directive. Protocols and timings shown are typical published ones — your local protocol takes precedence, and the vetting radiologist decides.

The request in front of you

Everything is optional. Leave a field alone and the answer assumes nothing — the verdict updates as you go.

Study requested

What the referrer actually asked for. It is evidence of intent, not a constraint on the right answer.

Contrast as written

What the request form says, not what it should say.

Age

Pick a band, or type an exact age if it matters.

years

Pregnancy status

Renal risk factors

The question a vetter can actually answer from the request. An explicit “none known” is a real answer, and it removes checks rather than deferring them.

Previous contrast reaction

The pathway — tap anything already done

Marking a study complete moves the answer on. A patient arrives partway through a pathway far more often than at the start of one.

Accept as requested

CT Coronary Angiogram — ECG-Synchronised

CT Coronary Angiogram (CCTA)

What we'd amend, and why

The coronary arteries are two to four millimetres wide and move several centimetres with every beat, so the entire protocol is an exercise in freezing them. Heart rate control to roughly 60 beats per minute and a regular rhythm are what make a prospectively triggered acquisition possible — the scanner captures a single narrow window in diastole, and if the rate is fast or irregular that window contains motion instead of anatomy. Sublingual nitrate dilates the epicardial vessels so a normal artery is not reported as diffusely diseased, and it needs several minutes to take effect before scanning starts. The reason the test is first-line is that it shows plaque as well as stenosis, so it distinguishes a patient with normal arteries — who can be reassured and needs no further cardiac testing — from one with non-obstructive disease who nonetheless benefits from preventive treatment.

Nothing needs resolving before this goes ahead. Routine checks below are owned downstream.

How was this decided?

pathwayadult — Adults
rulerule-contrast-reaction-premed — Prior contrast reaction and elective premedication; checked by Nurse before the scan
rulerule-metformin — Metformin and iodinated contrast; checked by Radiographer at the scanner
rulerule-paeds-dose — Child-sized technique and contrast dose; checked by Radiographer at the scanner
rulerule-paeds-sedation — Sedation or anaesthesia for a child; checked by Nurse before the scan
rulerule-renal-iodinated — Kidney function and intravenous iodinated contrast; checked by Radiographer at the scanner
rulerule-iv-access — Intravenous access adequate for the planned injection; checked by Radiographer at the scanner

Decision support only. Local protocol takes precedence.

Handled at the scanner(3)nothing for you to do

Settled and owned downstream. Each returns to a radiologist only on the stated trigger.

Metformin and iodinated contrast
Confirm whether the patient takes metformin or a metformin-containing combination, and if so whether ACR Category II applies (eGFR below 30, known or suspected AKI, or an arterial catheter study likely to cause renal embolisation). If Category I — that is, no AKI and eGFR at or above 30 — no action of any kind is needed.
Radiographer at the scannerAt the scanner
Flags back if: The patient takes metformin AND meets ACR Category II — eGFR below 30 mL/min/1.73 m2, known or suspected acute kidney injury, or an arterial catheter procedure with likely renal arterial embolisation. Metformin plus a normal or mildly reduced eGFR is explicitly NOT a flag-back: there is no need to stop metformin before or after intravenous iodinated contrast in Category I patients, and no need to re-check creatinine afterwards.
Child-sized technique and contrast dose
Confirm that a size- or weight-based protocol is selected — child-sized kV and mAs against size-based diagnostic reference ranges — and that contrast volume is calculated by weight rather than taken from an adult default. Weight-based iodinated contrast volumes of roughly 1.5–2.0 mL/kg are widely used in paediatric CT.
Radiographer at the scannerAt the scanner
Flags back if: No paediatric or size-based protocol exists on the scanner for the requested examination, or the requested coverage or number of phases exceeds what the clinical question needs — for example a multiphase study where a single phase answers it, or whole-body coverage for a focal question.
Intravenous access adequate for the planned injection
Site and test a cannula that supports the protocol flow rate, preferring an antecubital or large forearm vein, and observe the injection for extravasation. A 20-gauge or larger cannula is preferred for flow rates of 3 mL/s or more.
Radiographer at the scannerAt the scanner
Flags back if: No cannula can be sited that supports the protocol flow rate — for example only a 22-gauge hand or foot cannula for a CT angiogram needing 4–5 mL/s; or the only available access is a central line or port that is not labelled power-injectable; or an extravasation occurs.

Pathways

Big forks are separate pathways; the first whose conditions match is the one used.

Adults

Matches your inputsDefault

Role	Study & protocol	Why this answers the question
First line	CT Coronary Angiogram (CCTA) CT Coronary Angiogram — ECG-Synchronised usually appropriate	The coronary arteries are two to four millimetres wide and move several centimetres with every beat, so the entire protocol is an exercise in freezing them. Heart rate control to roughly 60 beats per minute and a regular rhythm are what make a prospectively triggered acquisition possible — the scanner captures a single narrow window in diastole, and if the rate is fast or irregular that window contains motion instead of anatomy. Sublingual nitrate dilates the epicardial vessels so a normal artery is not reported as diffusely diseased, and it needs several minutes to take effect before scanning starts. The reason the test is first-line is that it shows plaque as well as stenosis, so it distinguishes a patient with normal arteries — who can be reassured and needs no further cardiac testing — from one with non-obstructive disease who nonetheless benefits from preventive treatment.
Second line	Cardiac MRI Cardiac MRI — vasodilator stress perfusion	When the CT shows a stenosis of uncertain haemodynamic significance, the question changes from anatomy to physiology, and vasodilator stress perfusion answers it directly: a subendocardial perfusion defect appearing during first pass and absent at rest indicates a flow-limiting lesion. It is also the better first test where the CT would be uninterpretable — heavy calcification, extensive stenting, or an uncontrollable heart rate — and where radiation matters, as in younger patients requiring repeated assessment.
Problem solving	CT Coronary Artery Calcium Score CT Coronary Calcium Score — Unenhanced ECG-Gated	A short unenhanced gated acquisition performed immediately before the angiogram, used to predict whether the angiogram will be interpretable: a very heavy calcium burden blooms across the lumen and can make stenosis grading impossible, which is worth knowing before the contrast is given. It is a technical adjunct in this context, and a separate exposure — it should be requested deliberately rather than added by habit.

Pitfalls

Scanning an uncontrolled or irregular heart rate and reporting the result. Motion artefact mimics stenosis and, more dangerously, hides it.
Omitting nitrate, which leaves normal distal vessels looking diffusely narrowed.
Blooming from dense calcification systematically over-calls stenosis severity; grading should be done on thin axial and curved reformats and reported with an explicit statement of confidence.
Applying this pathway to a patient with known coronary disease or previous stenting, where CT performs much less well and functional testing or invasive angiography is more appropriate.
Requesting a calcium score instead of an angiogram in a symptomatic patient — a score of zero does not exclude non-calcified plaque and cannot exclude obstructive disease in someone with typical angina.

Priors — what to pull first

Check for a previous calcium score or coronary angiogram. A patient with established obstructive disease is not on this pathway at all, and CT angiography performs poorly in stented and grafted anatomy.
A previous CT of the chest for another reason often already shows the coronary calcium burden and can inform the discussion before anything is booked.

What makes a good request

A good request states the resting heart rate and rhythm, whether beta-blockade is contraindicated by asthma or bradycardia, whether nitrates are contraindicated, the ability to breath-hold, and the renal function.
Guidance genuinely diverges. NICE makes coronary CT angiography the first-line test for essentially all patients with angina and no known coronary disease, having abandoned formal pre-test probability calculation; the 2024 ESC chronic coronary syndrome guidance treats CT angiography and functional imaging as alternatives selected by pre-test likelihood, availability and local expertise. A department can defensibly follow either.
Acute chest pain in the emergency department is a different question with a different evidence base and belongs on an acute pathway.

Scoring this once it is done

The classification and risk tools this question ends in.

CAD-RADS 2.0 (Coronary CTA)Coronary Artery Calcium (Agatston) Score Categories eGFR (CKD-EPI 2021 Creatinine)

How these studies are acquired

Contrast, phases and timing for every study on the pathways above.

CT Coronary Angiogram — ECG-Synchronised Cardiac MRI — vasodilator stress perfusion CT Coronary Calcium Score — Unenhanced ECG-Gated

Confirm locally

CT Coronary Angiogram — ECG-Synchronised: timings are typical — confirm against local protocol.
Timings, contrast volumes and rates above are typical published values. Your department's protocol, scanner and patient population decide the actual numbers.
Safety thresholds and premedication policy follow local policy where it differs from the cited guidance.

References

Implemented from the cited published sources. Educational and workflow support only; confirm against current guidelines and local policy before clinical use.