The primary hypothesis of ROMA is that in patients undergoing primary isolated non-emergent coronary artery bypass surgery (CABG), the use of two or more arterial grafts compared to a single arterial graft is associated with a reduction in the composite outcome of death from any cause, any stroke, post discharge myocardial infarction and/or repeat revascularization. The secondary hypothesis is that in patients undergoing primary isolated non-emergent CABG, the use of two or more arterial grafts compared to a single arterial graft is associated with improved survival.

Prospective event-driven unblinded randomized multicenter trial of at least 4,300 subjects enrolled in at least 25 international centers. Patients will be randomized to a single arterial graft (SAG) or multiple arterial grafts (MAG). Patients will be randomized in a 1:1 fashion between the two groups. Permuted block randomization with random blocks stratified by the center and the type of second arterial graft will be used to provide treatment distribution in equal proportion.

In the 1980's, it was recognized that long-term survival was enhanced in patients undergoing coronary surgery when the left anterior descending (LAD) was grafted with a left internal thoracic artery (ITA) rather than a saphenous vein (1). This difference was predicated, at least in part, due to greater and more durable patency of the left ITA compared to an increased early occlusion rate and later progressive atherosclerosis of saphenous vein grafts (SVG) (2).

For more than 20 years it has generally been accepted that patients who receive multiple arterial grafts (AGs) at the time of coronary artery bypass surgery (CABG) have increased postoperative survival compared to those who receive only one AG, especially over the long term (3-5). The current United States and European Guidelines encourage the use of AGs in patients with a long life expectancy (6, 7). Last year, a position paper from the Society of Thoracic Surgeons strongly recommended a wider use of AGs (8).

The putative mechanism underlying the AG hypothesis is greater patency. In line with the original findings of improved LAD graft patency with ITA vs. SVG, data from randomized control trials (RCTs) as well as observational studies and a network meta-analysis (9) have demonstrated that the patency of the RA, as well as the right ITA, exceed that of a SVG, providing mechanistic basis to support the AG hypothesis.

ROMA is a two arm event driven randomized multi-centre trial aimed at evaluating the impact of the use of one ITA vs two or more AGs for CABG on a composite of death from any cause, any stroke, post discharge myocardial infarction and/or repeat revascularization. The trial is powered to detect a 20% relative reduction in the primary outcome with 90% power at 5% alpha.

The primary aim is to conduct a multicenter international randomized control trial to test the hypothesis that the use of a two or more AGs compared to a single arterial graft is associated with a reduction in the composite outcome of death from any cause, any stroke, post discharge myocardial infarction and/or repeat revascularization.

The secondary aim is to conduct a multicenter international randomized control trial to test the hypothesis that the use of two or more AGs compared to a single arterial graft is associated with improved survival.

Inclusion Criteria:

• Primary isolated CABG patients with disease of the left main coronary artery and/or of the left anterior descending and the circumflex coronary system with or without disease of the right coronary artery.

Exclusion Criteria:

• Age > 70 years
• Single graft
• Emergency operation
• Evolving myocardial infarction within 48 hours of surgery
• Left ventricular ejection fraction of < 35%
• Any concomitant cardiac or non-cardiac procedure
• Previous cardiac surgery
• Preoperative severe end-organ dysfunction (dialysis, liver failure, respiratory failure), cancer or any co-morbidity that reduce life expectancy to less than 5 years.
• Inability to use the saphenous vein or to use both radial and right internal thoracic arteries
• Anticipated need for coronary thrombo-endarterectomy
• Planned hybrid revascularization

The endpoint assessors will be blinded to treatment allocation (PROBE).