Randomised Controlled Trial to Assess Whether Computed Tomography Cardiac Angiography Can Improve Invasive Coronary Angiography in Bypass Surgery Patients

A large number of patients with symptomatic ischaemic heart disease undergo coronary artery bypass grafting (CABG) to alleviate their symptoms and improve prognosis. Given the progressive nature of coronary disease, bypass grafts can narrow or block over time, leading to chest pain and the need for further invasive coronary angiography. Invasive coronary procedures in patients with bypass grafts can be more complicated due to the variation in bypass graft ostia. This can lead to longer procedure times, with higher doses of contrast and radiation and more discomfort for the patient. The aim of this study is to see if the use of computed tomography cardiac angiography (CTCA) in patients with previous bypass grafts prior to invasive coronary angiography will help make their procedure safer and quicker.

The BYPASS-CTCA trial is a single-centre, randomised controlled trial, which plans to recruit 688 patients who have had previous bypass grafts and require invasive coronary angiography over a period of 30 months.

Patients will be randomised to receive either computed tomography cardiac angiography (CTCA) prior to their invasive coronary angiogram, or invasive coronary angiography alone.

The primary endpoints will be the incidence of contrast induced nephropathy, the duration of the invasive coronary angiographic procedure and patient satisfaction. A number of secondary endpoints will also be looked at.

Findings from BYPASS-CTCA will potentially demonstrate that a CTCA prior to invasive coronary angiography in this cohort of patients reduces the incidence of contrast-induced kidney injury, the length of procedure and improves patients satisfaction. The results of this trial may influence future clinical practice guidelines in coronary artery bypass graft patients undergoing invasive coronary procedures.

Eligibility Criteria:
Inclusion Criteria:

1. Patients undergoing invasive coronary angiogram +/- percutaneous coronary Intervention
2. Previous Coronary Artery Bypass Grafting (CABG)
3. Aged ≥18
4. Patients able and willing to give their written informed consent.

Exclusion Criteria:

1. Subjects presenting with ST elevation myocardial infarction, cardiogenic shock (systolic blood pressure \<80 mmHg for \>30 minutes, or requiring inotropes or emergency intra aortic balloon pump for hypotension treatment) or cardiopulmonary resuscitation.
2. Subjects with eGFR \<20ml/min or on renal replacement therapy.
3. Current life-threatening condition other than vascular disease that may prevent a subject completing the study.
4. Clinical instability including cardiogenic shock, hypotension (low blood pressure-systolic blood pressure less than 90 mmHg), sustained ventricular or atrial arrhythmia requiring intravenous medications.
5. Inability to tolerate beta-blockers, including those with chronic obstructive pulmonary disease or asthma, complete heart block, second-degree atrioventricular block
6. Known contrast dye allergy.
7. Pregnancy or unknown pregnancy status.
8. 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).
9. Inability or refusal to provide informed consent.
10. Any inclusion criteria not met