CTCA Prior to Invasive Angiography in Post-Bypass Patients (BYPASS CTCA 2)

A Multi-Centre, Randomised Trial Assessing the Value of Computed Tomography Coronary Angiography Prior to Invasive Coronary Angiography in Patients With Previous Coronary Artery Bypass Grafts in Reducing Cardiac Events

The goal of this clinical trial is to evaluate whether a coronary computed tomography angiography (CTCA)-guided strategy can reduce the risk of death, heart attack, stroke, and hospital admissions in patients experiencing angina or myocardial infarction following coronary artery bypass graft (CABG) surgery. The main questions it aims to answer are:

• Can CTCA reduce major adverse cardiovascular events compared to standard invasive coronary angiography?
• Is CTCA a cost-effective and safer alternative that improves patient quality of life? Researchers will compare outcomes between patients receiving CTCA prior to angiography and those undergoing standard angiography alone to determine if CTCA improves clinical outcomes and procedural safety.

Participants will:

• Be randomly assigned to either CTCA-guided care or standard angiography
• Undergo coronary imaging and follow-up assessments
• Complete questionnaires on quality of life and healthcare resource use

Patients with prior coronary artery bypass graft (CABG) surgery frequently present with recurrent angina or acute coronary syndromes due to progressive native coronary artery disease or graft failure. Invasive coronary angiography remains the standard diagnostic approach but is technically challenging in this population due to variable graft anatomy, leading to prolonged procedure times, increased radiation exposure, higher contrast volumes, and elevated risk of procedural complications.

Computed Tomography Coronary Angiography (CTCA) offers a non-invasive alternative with high diagnostic accuracy for graft patency and coronary anatomy. Prior observational data (e.g., BYPASS-CTCA study) suggest that CTCA performed prior to invasive angiography may improve procedural efficiency and safety. However, whether CTCA can guide clinical decision-making to avoid unnecessary angiography and improve long-term outcomes remains unproven.

This multi centre, randomised controlled trial will enrol 1,000 patients with prior CABG presenting with angina or myocardial infarction. Participants will be randomised to either a CTCA-guided strategy or standard care involving direct invasive coronary angiography. In the CTCA arm, angiography may be deferred if CTCA findings support medical management. The primary outcome is the composite rate of major adverse cardiovascular events (MACE), including death, myocardial infarction, stroke, and hospitalisation for unstable angina. Secondary outcomes include procedural metrics, patient-reported quality of life, cost-effectiveness, and healthcare resource utilization.

Clinical data will be collected through patient questionnaires, procedural records, and central registry downloads. The study incorporates patient and public involvement throughout its design and implementation. Results will be disseminated via peer-reviewed publications, public-facing reports, and digital platforms.

Inclusion Criteria:

• Aged ≥18

• Previous coronary artery bypass grafting (CABG)

• An indication for coronary angiography

  • Angina
  • Ischaemia on perfusion imaging
  • Acute coronary syndrome

• Patients are able and willing to give their written informed consent

Exclusion Criteria:

• Subjects presenting with ST segment myocardial infarction within window for primary PCI
• Patients considered unsuitable to participate by the research team (e.g. due to medical reasons, laboratory abnormalities, or subject's unwillingness to comply with all study related procedures)
• Life expectancy less than 1 year