ART: A randomised trial to compare survival following bilateral versus single internal mammary (IMA) grafting in coronary revascularisation 

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	Presenter
	Presenter | see Discussant report
Taggart, David (United Kingdom)

List of Authors:

Abstract:

OBJECTIVES:
Recent trial data indicate that coronary artery bypass graft (CABG) surgery remains the most effective intervention for patients with severe coronary artery disease (CAD). Over two decades ago, the use of a single internal mammary artery (SIMA) during CABG was demonstrated to improve survival and freedom from myocardial infarction, recurrent angina and repeat intervention. Observational data suggest that using bilateral internal mammary arteries (BIMA) may provide even superior revascularisation with improved long-term survival and reduced need for repeat CABG. However, < 5% of patients undergoing CABG in Europe and the USA receive BIMA because of concerns that, as it is technically more challenging and takes longer, it increases early mortality and major morbidity including impaired sternal wound healing.

The Arterial Revascularisation Trial (ART), one of the largest trials ever conducted in cardiac surgery, is a randomised trial of BIMA grafts versus SIMA grafts whose primary outcome is survival at 10 years. Secondary end-points include clinical events, quality of life and cost effectiveness. We report safety data in the whole cohort up to 1 year after randomization.

METHODS:
ART is an investigator initiated trial funded by the UK MRC and British Heart Foundation with 28 participating centres in Australia, Austria, Brazil, India, Italy, Poland and the UK. Eligible CABG patients (ie. no contraindication to BIMA grafts), were randomised to SIMA or BIMA grafting with supplementary grafts (saphenous vein or radial artery) as necessary. CABG could be performed as an on-pump or off-pump procedure. The effect of age, LV function, diabetes and off-pump surgery are pre-specified subgroup analyses.

RESULTS:
Between June 2004 and December 2007, a total of 3102 patients were randomised to receive SIMA (n=1554) or BIMA (n=1548). The mean age was 64 years (SD 9) with 86% males. 24% of patients had diabetes, 42% had prior MI and 16% prior PCI. Ejection fraction was > 50% in 73% of patients. 40% of the SIMA procedures and 42% of the BIMA procedures were performed off-pump. Mean operation time was 3 hours 19 minutes (SD 58 minutes) in the SIMA group and an additional 23 minutes in the BIMA group. Ventilation time was a median (IQR) of 578 minutes (335-830) in the SIMA group and 598 minutes (360-890) in the BIMA group. Overall 30 day mortality was 1.2% in each group and one year mortality was 2.4% in the SIMA group and 2.5% in the BIMA group. At 6 weeks the incidence of sternal wound reconstruction was 0.5% in the SIMA group and 1.5% in the BIMA group. Median duration of hospital stay post operation was 6 days in the SIMA group and 6.5 days in the BIMA group. Data will be presented at the ESC Congress on the following clinical events in-hospital and up to one year; CVA, myocardial infarctions and further revascularisation.

CONCLUSIONS:
ART is the one of the largest randomised trials ever conducted in cardiac surgery and the preliminary results demonstrate that, in contrast to the widespread surgical perception that BIMA grafting increases early surgical mortality and major morbidity, these were similar in both groups at 30 days and 1 year. There is a small increase in the need for sternal wound reconstruction using BIMA from 0.5% to 1.5%. These 1 year outcome data suggest that it is safe to use BIMA in a far higher proportion of patients undergoing CABG. Longer term analyses will indicate whether SIMA or BIMA strategies have particular advantages in specific sub-groups.

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	Discussant
	Discussant | see Presenter abstract
Kappetein, A Pieter (Netherlands)

Report:

A single internal mammary artery (SIMA) rather than vein graft to the left anterior descending coronary artery is undoubtedly the standard therapy in coronary bypass surgery. Surprisingly, the usage of 2 mammary arteries has not been accepted as the standard of care and the benefits and disadvantages have been a matter of debate for years. Numerous compelling retrospective studies have documented a clear benefit for bilateral mammary artery grafting (BIMA) over SIMA grafting in reducing the long-term risk of death, cardiac death and late cardiac events. Nevertheless there is a wide discrepancy between these findings in the literature and clinical practice.

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Full text of the Hot Line Commentary published in European Heart Journal Conclusion

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.