Heart surgery - ART

The clinical question

Coronary artery bypass grafting (CABG) is a procedure used to treat people diagnosed with coronary heart disease. During CABG, surgeons use a piece of blood vessel taken from the leg, arm or chest to bypass a narrowed section of one or more coronary arteries supplying the heart. Most patients undergoing CABG have several narrowed areas in their coronary arteries, requiring more than one piece of ‘bypass’ vessel. 

The current standard way of performing CABG is to use one of the two arteries supplying blood to each side of the inner chest (the internal thoracic artery). Surgeons then use additional vessel grafts as needed. Typically, this will be pieces of vein taken from the leg, or pieces of artery taken from the arm. This procedure is usually successful at relieving symptoms in the short term. But grafted vessels, particularly veins, can become blocked or diseased over time. This can lead to symptoms returning and the need for further treatment. 

An international team of researchers - led by Professor David Taggart at the University of Oxford - wanted to find out if a less commonly performed operation, using both internal thoracic arteries, could lead to better long term outcomes for people having CABG. The ‘Arterial Revascularisation Trial’ (ART) was funded by the BHF in partnership with the Medical Research Council and the UK National Institute for Health Research.

What did the study involve?

Between 2004 and 2007, the trial recruited 3102 people undergoing CABG across the UK, Australia, Austria, Brazil, India, Italy and Poland. Participants were randomly assigned to:

• Have surgery using both internal thoracic arteries as grafts.

• Have surgery using one internal thoracic artery as a graft. Surgeons used additional pieces of vein or an artery from the arm to bypass other vessels as needed. 

The researchers then followed the health records of these patients over the next 10 years.

What did the study find?

• There were no differences in survival or the risk of heart attack or stroke between the two groups at 1, 5 or 10 years after treatment.

• The surgery using two internal thoracic arteries increased the risk of complications from the surgical wound. 

However, the results of this study were complicated by the high variation in surgical or medical treatment received by participants.  For example, 14% of people who were meant to receive two internal thoracic artery grafts actually received one. And there was a lot of variation in the different combinations of artery or vein grafts used. This meant that about 40% of participants in the trial received a different treatment to that planned for them.

The researchers found that those who received more than one artery graft overall – from either the internal thoracic artery or the radial artery in the arm – were more likely to survive 10 years after the surgery. This was compared to those who received one artery graft plus one or more vein graft. 

Why is the study important?

Professor Taggart, who presented the results of ART at the 2018 European Cardiology Society Conference in Munich, said: “ART is one of the largest trials with the longest duration of follow-up ever undertaken in cardiac surgery to guide future practice with regards to selecting which vessel to use for coronary bypass surgery.”

Members of the ART research team are now taking part in a new trial - the ‘Randomization of Single vs Multiple Arterial Grafts’, or ‘ROMA’ study. This trial will recruit patients undergoing CABG from across the world. It aims to test more definitively whether using multiple artery grafts is a better approach for this surgery.

Study details

"A randomised trial to compare survival following bilateral versus single internal thoracic (IMA) grafting in coronary revascularisation." 
Award reference: SP/03/001/14539, joint funding with MRC
Principal Investigator: Professor David Taggart, University of Oxford
Trial registration number: ISRCTN46552265

Publication details

1 year results - Taggart DP, Altman DG, Gray AM, et al. Randomized trial to compare bilateral vs. single internal mammary coronary artery bypass grafting: 1-year results of the Arterial Revascularisation Trial (ART). Eur Heart J. 2010;31(20):2470-81.

5 year results - Taggart DP, Altman DG, Gray AM, et al. Randomized Trial of Bilateral versus Single Internal-Thoracic-Artery Grafts. N Engl J Med. 2016;375(26):2540-9.

10 year results - Taggart DP, Benedetto U, Gerry S, et al. Bilateral versus Single Internal-Thoracic-Artery Grafts at 10 Years. N Engl J Med. 2019;380(5):437-446.