Study Finds No Difference in Patency Between Radial Artery Grafts and Saphenous Vein Grafts

A new study of angiographic patency for male patients undergoing first-time elective coronary artery bypass grafting (CABG) found no difference in 1-year patency for those who had radial artery grafts compared with those who received saphenous vein grafts. The findings from the randomized trial were published in the Journal of the American Medical Association [2011;305(2):167-174]. It is estimated by the Society for Thoracic Surgery that >163,000 patients received CABG surgery in the United States in 2008; however, the success of this common operation depends on the long-term patency of arterial and venous grafts. According to the authors of this recent prospective study, little is known about the effectiveness of radial artery grafts in patients over time. In this trial, which was sponsored by the Department of Veterans Affairs (VA) Cooperative Studies Program, researchers sought to learn more about radial artery grafts by creating a study that compared the 1-year patency of patients randomly assigned to receive either radial artery grafts or saphenous vein grafts during first-time CABG surgery. The study included 733 patients selected from 11 VA medical centers from February 2003 to February 2009. According to researchers, whenever it was possible, the left internal mammary artery was used to preferentially graft the left anterior descending coronary artery during surgery, while the best remaining recipient vessel was randomized to either a radial artery or saphenous vein graft. After surgery, patients were instructed to take aspirin daily for at least a year. Postoperative followups were also conducted every 3 months, and a graft angiography was done 1 week and again 1 year after surgery. Those patients who had an occluded study graft at 1 week or those who had a clinically indicated angiogram within 1 year after surgery were not given another angiography at the 1-year mark. The primary outcome of the study was angiographic graft patency 1 year after surgery. Secondary end points were also identified and included myocardial infarction, stroke, repeat coronary revascularization, and death. During the study, researchers reported that 5% of patients (95% confidence interval [CI], 3%-7%) in the radial group and 20% of patients (95% CI, 16%-24%) in the saphenous vein group had endoscopic vessel harvesting (P<.001). Researchers found that there was no significant difference in graft patency at 1 year between the radial artery group (238/266, 89%; 95% CI, 86%-93%) and the saphenous vein graft group (239/269, 89%; 95% CI, 85%-93%; unadjusted odds ratio, 1.07; 95% CI, 0.62-1.84; P=.82). They also found no significant differences for any of the secondary end points. During the study, researchers also compared cost estimates of the 2 procedures but did not find any significant difference in the mean cost of the hospital stay for either group. However, researchers did find that there was a higher incidence of a 99% occlusion in the radial artery graft group (21/266, 8%; 95% CI, 5%-11%) than there was in the saphenous vein graft group (3/269, 1%; 95% CI, 0%-2%; P<.001). They also noted that the 1-year patency was lower for those patients in the saphenous vein group who had endoscopic vessel harvesting (40/51, 78%; 95% CI, 67%-90%) compared with those in the saphenous vein group who had other vessel harvesting (199/218, 91%; 95% CI, 88%-95%; P=.009). However, in the radial artery group, there was no significant difference in patency based on the form of vessel harvesting. The researchers concluded that they did not find a significant difference between the radial artery graft or the saphenous vein graft groups in terms of patency; however, they believe further study is needed to evaluate the long-term patency of each method. The VA Cooperative Studies Program plans to follow these patients and conduct a 5-year angiography to learn more.