...surgeons have a choice between using the radial artery or a saphenous vein graft...

For many years, the surgeon's graft of choice for patients undergoing CABG surgery has been the left internal mammary (thoracic) artery (LIMA). The basis of this strategy is the evidence that graft patency and patient outcomes are superior with the LIMA than with other potential conduits, such as the saphenous veins. The LIMA is, therefore, the most commonly used graft for the left anterior descending coronary artery, with vein grafts often used for the other coronary vessels. Over the past decade, interest has grown in identifying other arterial conduits that could rival the LIMA in terms of clinical benefit and, therefore, be used as an alternative graft. The radial arteries are an obvious choice, since they are easy to harvest without substantial long-term adverse effects. Dr Steven Goldman, from the Southern Arizona Veterans Affairs (VA) Health Care System, and his colleagues have now reported that the patency of radial artery grafts and saphenous vein grafts did not differ significantly at 1 year after CABG surgery in a randomized controlled trial of patients treated at VA hospitals.

The analysis included 733 patients (99% of whom were male) who were randomly assigned in a 1:1 ratio to receive a radial artery graft or a saphenous vein graft for a first, elective, CABG surgery. The two treatment groups were balanced in terms of baseline demographic and clinical characteristics. Coronary angiography was performed to assess graft patency at 1 year (the primary end point) after surgery.

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After 1 year of follow-up, the graft patency rate was the same for each of the two groups (radial artery: 89%, 95% CI 86–93%; saphenous vein: 89%, 95% CI 85–93%). The statistical nonsuperiority of radial artery use was maintained when the results were adjusted for confounding factors, including differing target vessel, on-pump versus off-pump surgery, and the patient's smoking status. Although the incidence of hemorrhage (requiring a blood transfusion) was lower among patients who received a radial artery graft than in the saphenous vein graft group (0.8% versus 3.3%, P = 0.03), radial artery grafts were associated with increased evidence of vasospasm ('string sign'). Notably, among patients with diabetes (42% in each treatment group), the saphenous vein seemed to be the preferable choice of graft, with a patency rate significantly higher than for the radial artery (P = 0.04). This finding could be related to the fact that arterial grafts are more prone to the development of atherosclerosis and calcification in patients with diabetes than in those without this condition.

“Based on these 1-year data, surgeons have a choice between using the radial artery or a saphenous vein graft,” says Dr Goldman, but looking to the future, he continues “because the important question is long-term patency, the VA Cooperative Studies Program has funded a 5-year angiographic follow-up of these patients to define chronic graft patency in this population.” The results will be eagerly awaited.