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Purpose and principlesIndications, selection and cautionsMethod and interpretationClinical next stepsRisks, monitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Cardiac catheterisation and coronary angiography

Cardiology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Time-critical presentation

Activate immediate invasive management for STEMI and for NSTE-ACS with haemodynamic instability, recurrent or refractory pain, life-threatening arrhythmia or acute heart failure; stabilisation and transfer should occur in parallel.

Purpose and principles

Use invasive angiography and haemodynamic catheterisation when results will change treatment, while reducing access, bleeding, kidney and radiation harm.

Invasive angiography is justified when pre- or post-test probability is high, symptoms remain severe despite medical therapy, anatomy is high risk, ACS timing requires it or non-invasive tests are inconclusive and a result will change management.

The report should describe access, coronary dominance, lesion site and severity, flow, physiology, collateral vessels, complications, contrast and radiation, and any intervention. A visual percentage alone is inadequate for an intermediate lesion.

Diagnostic catheterisation and PCI are related but separate consent decisions. Ad hoc PCI is appropriate only when the likely options and alternatives were discussed and anatomy supports it.

Key points

  • Coronary angiography defines lumen anatomy but does not show plaque biology or prove that an intermediate stenosis causes ischaemia.
  • Use FFR or a validated non-hyperaemic pressure ratio to assess intermediate lesions before revascularisation when functional significance is uncertain.
  • Radial access usually reduces access-site bleeding and permits earlier mobilisation, but anatomy and procedure may require femoral access.
  • Before the procedure review indication, alternatives, consent, renal function, blood count, coagulation, allergies and all antithrombotic medicines.
  • Right-heart catheterisation measures pressures, cardiac output and shunt data when non-invasive assessment is insufficient for a decision.
  • New chest or back pain, hypotension, neurological deficit, limb ischaemia or enlarging access swelling after catheterisation is an emergency.
  • A normal angiogram in a patient with angina can redirect assessment toward vasospasm or microvascular dysfunction rather than proving symptoms are non-cardiac.

Indications, selection and cautions

High-risk coronary anatomy

Left main or complex proximal multivessel disease prompts urgent Heart Team consideration of PCI versus CABG, clinical state permitting.

Coronary occlusionRed flag

Acute occlusion with an ACS presentation requires immediate reperfusion strategy and antithrombotic management.

Access-site bleedingRed flag

Persistent bleeding, expanding haematoma, hypotension or falling haemoglobin requires compression, resuscitation and urgent vascular assessment.

Retroperitoneal haemorrhageRed flag

Back or flank pain, hypotension and unexplained anaemia after femoral access may occur without obvious groin swelling.

Contrast-associated or embolic complicationRed flag

Oliguria, acute neurological deficit, coronary dissection, no-reflow or limb ischaemia requires prompt targeted escalation.

Method and interpretation

  1. 01
    Invasive coronary angiographyFirst step
    Why
    Define coronary anatomy and enable revascularisation in appropriate ACS or chronic coronary syndromes.
    Interpretation and limitations
    Describe lesion distribution and flow; use physiology or intravascular imaging when angiography alone cannot answer significance or mechanism.
  2. 02
    FFR or non-hyperaemic pressure ratio
    Why
    Determine whether an intermediate epicardial stenosis is functionally significant.
    Interpretation and limitations
    Use validated thresholds, check for pressure drift and interpret within the clinical and microvascular context.
  3. 03
    IVUS or OCT
    Why
    Clarify lesion morphology, left-main severity, stent sizing or complications and selected uncertain diagnoses.
    Interpretation and limitations
    Intravascular imaging adds vessel-wall detail but introduces procedural and, for OCT, contrast considerations.
  4. 04
    Right-heart catheterisation
    Why
    Measure right-sided filling and pulmonary pressures, cardiac output and shunt data, and estimate left-sided filling pressure from pulmonary artery wedge pressure when a decision depends on direct haemodynamics.
    Interpretation and limitations
    Pulmonary artery wedge pressure is an estimate rather than a direct LV end-diastolic pressure; level and zero the transducer correctly because respiratory phase, oxygen, ventilation and volume state alter measurements.

Clinical next steps

01Preferred routeChronic coronary syndromeFirst stepPreferredSevere refractory symptoms, high event risk or high pre/post-test likelihood+
  1. 1Confirm the indication, optimise guideline-directed therapy and review non-invasive anatomy or ischaemia.
  2. 2AlternativeObtain informed consent covering diagnostic angiography, possible PCI, CABG alternative and material risks.
  3. 3Perform angiography with radial access when suitable and use invasive physiology for intermediate stenoses.
  4. 4Use shared or Heart Team decision-making for complex anatomy and document the prevention plan regardless of revascularisation.
02AlternativeNSTE-ACS invasive timingAlternativeUnstable angina or NSTEMI+

Risks, monitoring and follow-up

  • Before and after the procedure monitor observations, access site and distal neurovascular status.
  • Record contrast volume, radiation dose and fluoroscopy time and minimise repeat exposure.
  • Recheck haemoglobin or renal function when bleeding, kidney risk or clinical change warrants it.
  • After PCI document antiplatelet agent, dose, intended duration and what to do before any interruption.
  • Confirm follow-up of non-culprit disease, staged procedures and cardiac rehabilitation.

Special situations

Visual stenosis is imprecise

Intermediate lesions are commonly over- or underestimated; physiology can prevent both missed treatment and unnecessary stenting.

Radial has its own checks

Reduced major bleeding does not remove the need to monitor hand perfusion, haematoma and radial occlusion.

Haemodynamics need context

Sedation, positive-pressure ventilation, oxygen and diuresis can materially change catheter measurements.

Normal lumen is not normal function

Vasospasm and microvascular dysfunction can cause genuine ischaemic symptoms despite non-obstructive angiography.

Consent anticipates forks

Discuss possible medical therapy, physiology, PCI and surgical referral before sedation whenever foreseeable.

Common pitfalls

  1. 01

    Stenting an intermediate lesion from visual estimate alone when physiology is appropriate.

  2. 02

    Missing retroperitoneal bleeding because the groin looks normal.

  3. 03

    Failing to reconcile anticoagulants and antiplatelets before and after the procedure.

  4. 04

    Calling non-obstructive angiography a non-cardiac diagnosis.

  5. 05

    Documenting 'angiogram plus or minus PCI' without meaningful discussion of alternatives and DAPT implications.

Practice

Two practice questions

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Question 1 of 2
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CardiologyOriginal SBA

Intermediate lesion

A stable patient has a visually intermediate coronary stenosis at angiography and no prior functional evidence. What is the preferred next assessment before PCI?

Choose one answer, then submit
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Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Apply principles in context and verify current guidance when a decision affects care. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • NICE CG95: Recent-onset chest pain
  • NICE NG185: Acute coronary syndromes
  • ESC 2024 Guidelines for chronic coronary syndromes
  • ESC 2023 Guidelines for acute coronary syndromes

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom
  • 05
    Pre-procedure blood tests
    Why
    Assess haemoglobin, platelets, renal function, electrolytes and coagulation where relevant.
    Interpretation and limitations
    Use results to modify access, contrast, antithrombotic and hydration strategy rather than cancelling automatically.
    • 1
    Use immediate angiography for clinical instability, recurrent refractory pain, life-threatening arrhythmia or acute heart failure.
  • 2Offer angiography within 72 hours when NICE risk assessment indicates predicted 6-month mortality above 3% and there is no contraindication.
  • 3Individualise conservative management when comorbidity or bleeding risk outweighs benefit, documenting the reasoning.
  • 4Do not give prasugrel before coronary anatomy is known.
    • 03EscalationPost-procedure deteriorationEscalationHypotension, pain, bleeding, neurological change, dyspnoea or limb symptoms+
    1. 1Perform ABCDE, inspect access, check distal perfusion and obtain ECG and urgent blood tests.
    2. 2Control external bleeding and reverse or modify antithrombotic therapy only with senior procedural input unless immediately life-saving.
    3. 3Use urgent echo, CT or repeat angiography according to suspected tamponade, bleeding, stroke or vessel complication.
    4. 4EscalationEscalate directly to interventional cardiology, vascular surgery, stroke or critical care as indicated.