Low Long-Term Patency Rates Seen With Radial Artery Bypass Grafts

While there has been a dramatic rise in the use of radial artery grafts during cardiac bypass surgery in recent years, findings from a new study, which shows higher long-term patency rates for other graft types, may dampen some of the enthusiasm for radial artery grafts.

With an average follow-up period of 565 days, the patency rate for such grafts was just 51.3%, markedly lower than the 90.3% rate seen for left internal mammary artery (IMA) grafts (p < 0.0001). In fact, even saphenous vein grafts (SVG) were associated with a higher patency rate of 64.0% (p = 0.0016), according to the report published in the May 4th rapid access issue of Circulation: Journal of the American Heart Association. “Most studies comparing radial artery grafts with left IMA and saphenous vein grafts have looked at outcomes within 1 year of surgery,” lead author Dr. Umesh N. Khot, from Indiana Heart Physicians in Beech Grove, told Reuters Health. “In that time frame, all three graft types tend to do well.” “Our study looked at patients a little bit farther out in time and it included patients who were returning with problems,” Dr. Khot noted. “The results suggest that radial artery grafts aren’t doing as well as we expected them to.” The findings are based on a study of 310 patients who underwent CABG that included at least one radial artery graft at The Cleveland Clinic between 1996 and 2001. The grafts used in the group included 398 radial artery, 272 SVG, 269 left IMA, and 77 right IMA. Occlusion rates and severe stenosis rates were also higher with radial artery grafts than with other types. For example, radial artery grafts had an occlusion rate of 33.7%, while left IMA grafts had a rate of just 4.8% (p < 0.0001). Similarly, the severe stenosis rate for radial artery grafts--15.1%--was about 10% higher than that seen with the other graft types. Women appeared to be particularly poor candidates for radial artery grafts with a patency rate of only 38.9%–much lower than the 56.1% rate seen in men (p < 0.0001). On multivariate analysis, radial artery graft was the strongest predictor of severe stenosis or occlusion, the researchers report. Due to a diseased radial artery graft, 84 patients required revascularization procedures, including 26 who underwent repeat CABG. “The findings suggest that instead of having 100% enthusiasm for radial artery grafts, we need to pause for a moment and really question whether they’re doing what we’re claiming them to be doing,” Dr. Khot said. Circulation 2004;109.