Occlusion Less in Radial-Artery Than Saphenous-Vein Bypass Grafts
In bypassing the right coronary artery or circumflex artery, radial-artery grafts provide better 1-year patency than saphenous-vein grafts, according to a report in the November 25th issue of The New England Journal of Medicine. However, the results suggest that radial-artery grafts should preferentially be used for high-grade lesions.
The findings are based on a study of 561 patients with triple vessel disease who were randomized to have the right coronary bypassed with a radial-artery graft and the circumflex bypassed with a saphenous-vein graft or to the converse situation. In all patients, the anterior circulation was bypassed with the left internal thoracic artery.
Dr. Stephen E. Fremes and colleagues, from the University of Toronto, note that angiographic follow-up at 1 year was available for 440 patients. This showed that at 1 year, 8.2% of radial-artery grafts were totally occluded compared with 13.6% of saphenous-vein grafts.
In contrast, saphenous-vein grafts were associated with a lower risk of diffuse graft narrowing on angiography. This finding was observed in 7% of radial-artery grafts, but just 0.9% of saphenous-vein grafts (p = 0.001).
Using a radial-artery graft on a vessel without severe stenosis increased the risk of occlusion and diffuse graft narrowing. Thus, the authors note that it is best to use such grafts for target vessels with high-grade lesions.
In a related editorial, Dr. Bruce W. Lytle of the Cleveland Clinic Foundation, comments that it is possible that radial-artery grafts will supplant not only saphenous-vein grafts, but also right internal thoracic artery (RITA) grafts.
“Because of the increased technical difficulty of operation with bilateral internal thoracic-artery grafting,” he notes, “if the long-term patency of radial-artery grafts is shown to approach the patency rates of RITA grafts, radial-artery grafts are likely to be substituted for RITA grafts as well as for saphenous-vein grafts in the future.”
