Midterm endothelial function and remodeling of radial artery grafts anastomosed to the aorta

Background: The purpose of this study was to elucidate the midterm endothel ium-dependent vasodilatory capacity of radial artery grafts anastomosed to the aorta, as well as their morphometric evolution with the time. Methods: Five years after surgery we evaluated the response of aorta-anasto mosed radial artery grafts to the endovascular infusion of acetylcholine in 11 of the first 61 patients operated on at our institution, and we compare d it to the response with that of internal thoracic artery grafts. Moreover , the first 20 patients who had a perfect radial artery graft on angiograph y at 1 year were restudied at 5 years and subjected to a comparative analys is of the diameters of the radial artery graft and the grafted coronary art eries. Results: At midterm angiography, dilation of the 2 types of grafts was simi lar in response to acetylcholine administration (radial artery, from 2.61 /- 0.39 to 2.90 +/- 0.34 mm; internal thoracic artery, from 2.68 +/- 0.21 t o 2.93 +/- 0.27 mm; P =.01 for both). The diameters of aorta-anastomosed ra dial artery grafts and grafted coronary arteries increased between both 1 a nd 5 years according to angiographic studies (radial artery grafts, from 2. 08 +/- 0.45 to 2.54 +/- 0.53 mm; grafted coronary arteries, from 1.92 +/- 0 .47 to 2.18 +/- 0.41 mm; P <.001 for both), but the increase was greater fo r the radial artery grafts (P <.001). Conclusions: Aorta-anastomosed radial artery grafts maintain an appreciable capacity for endothelium-dependent vasodilatation 5 years after implantati on and undergo a progressive increase in luminal diameter with time. These observations contradict the presumed tendency for progressive fibrous intim al hyperplasia to develop in radial artery grafts.