BYPASS-CTCA-MACE: 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

Is a Computed Tomography Coronary Angiography (CTCA) guided strategy superior to invasive angiography alone in patients with previous coronary artery bypass surgery with recurrent symptoms.

Background: Invasive coronary angiography (ICA) is the gold standard for the assessment of patients with prior coronary artery bypass graft surgery (CABG) who present with cardiac chest pain, however it is more challenging than in patients without grafts.

Procedures last longer and have an increased risk of complications, with stroke and contrast-associated kidney injury being approximately three and four times higher respectively, compared with patients without previous CABG.

A recent single centre randomised controlled trial (BYPASS-CTCA) demonstrated that performing a computed tomography coronary angiography (CTCA) scan prior to an invasive coronary angiogram is beneficial.

The group assigned CTCA had angiograms that were shorter, rates of contrast associated kidney injury were reduced, and patient satisfaction was increased. Major adverse cardiovascular events (MACE) were also lower in the CTCA+ICA group. However, whether the CTCA can replace invasive angiography and improve outcomes in these patients is unknown.

This study will specifically address the limitations of the BYPASS-CTCA trial in a multi-centre powered study assessing whether using CTCA as gatekeeper to coronary angiography improves clinical outcomes in patients with previous CABG.

Aims and Objectives: This study aims to assess whether in patients with previous CABG with an indication for invasive coronary angiography, does a CTCA guided strategy reduce MACE compared to a coronary angiography alone strategy.

Methods: BYPASS-CTCAMACE is a multi-centre, randomised controlled trial of a CTCA guided strategy versus invasive coronary angiography in patients with previous CABG. 930 patients with a history of previous CABG and an indication for angiography will be randomised (1:1) to upfront CTCA or invasive angiography alone (standard of care).

Randomisation will be stratified by the centre and type of presentation (ACS).

The primary endpoint is major adverse cardiovascular events (all-cause mortality, stroke, myocardial infarction, cardiac hospitalisation) during follow-up. Key secondary endpoints include days alive and out of hospital, quality of life, and the cost effectiveness of CTCA. The trial will be registered with clinicaltrials.gov.

Timelines for delivery: The trial is expected to last for 36 months in total, with 24 months recruitment, minimum 6-month follow-up and 6-months for set-up/analysis and close-out.

Anticipated Impact and Dissemination: The findings of this study will be disseminated in a variety of formats to improve accessibility to the medical community, patients and society. PPI representatives will assist with the dissemination of findings.

Publication in international high impact medical journals and presentation at national and international cardiology and general medicine conferences will be planned, alongside presentation in online fora including podcasts and blogs.

If the results challenge the current first line treatment of coronary angiography, a change to the standard of care could be implemented within 5-years with potential to improve the lives of CABG patients with further symptoms. Potential indirect benefits to the NHS include reduced need for hospital attendances and admissions.