Are two internal thoracic artery grafts as safe as one?

In the current issue of the Journal, Baradi and colleagues report a retrospective study of short-term outcomes in two groups, each of 637 patients, undergoing either BITA or SITA CABG matched for age, gender, body surface area, diabetes and hypertension.1 They report no significant difference in the composite primary endpoint, nor of any of its individual components, between patients receiving BITA or SITA. They consequently imply that the use of BITA is as safe as SITA and recommend there should be increased utilisation of BITA in selected patients.This issue is very important. Significant new evidence has emerged recently of the superiority of CABG over PCI for most patients with multi-vessel coronary artery disease.2,3 While the benefits of a SITA graft were firmly established over a quarter of a century ago, more than 10 years ago strong evidence emerged of the potential survival benefits of BITA grafts.4 The proven superiority of the long-term patency of BITA grafts in comparison to vein grafts when placed to the left sided coronary vessels is the likely explanation. Furthermore while the use of BITA grafts has additional survival benefit for younger patients it allows, with composite grafting techniques, the development of a truly off pump no touch aortic technique in those at higher risk of stroke.Yet, in a survey of UK Cardiac Surgeons, although the majority believed that there were potential benefits for most CABG patients with two BITA grafts,5 in reality they were used in only a relatively small number of patients. A decade later currently fewer than 10% of patients in Europe and 5% in the USA receive BITA grafts.Consequently the ART Trial, a prospective randomised trial of 3100 patients operated on by 67 surgeons in 7 different countries, was established to determine if there are long term benefits of BITA grafts and, if so, in what patient groups.6 Crucially the one-year outcomes were published as "a safety endpoint" and showed that the use of BITA grafts did not increase the risk of death, myocardial infarction or stroke in comparison to a single ITA graft. From the surgical perspective harvesting a second ITA graft added 23 minutes to operation time and an extra hour and half of ventilation in patients who were ventilated for around 12 hours.The one crucial difference was an increase in the risk of sternal wound reconstruction from 0.6% in the SITA group to 1.9% in the BITA group (translating in to a number needed to harm of around 78 patients with each BITA operation). Current analysis of the ART data will identify which patients were at most risk of sternal dehiscence and this is almost certainly likely to be in obese diabetic patients. However even this risk can be reduced with more selective use of BITA and a skeletonisation harvest technique.Considering its proven angiographic superiority, the very low rates of BITA use is an indictment of the practice of contemporary CABG. For those who argue that there is no evidence from RCTs to support BITA use the same is true for the use of a SITA graft.Use of BITA grafts should be in the routine surgical armamentarium of all cardiac surgeons.