Preserved endothelium-dependent vasodilation in coronary segments previously treated with balloon angioplasty and intracoronary irradiation

Background-Abnormal endothelium-dependent coronary vasomotion has been repo rted after balloon angioplasty (BA), as well as after intracoronary radiati on. However, the long-term effect on coronary vasomotion is not known. The aim of this study was to evaluate the long-term vasomotion of coronary segm ents treated with BA and brachytherapy. Methods and Results-Patients with single de novo lesions treated either wit h BA followed by intracoronary beta-irradiation (according to the Beta Ener gy Restenosis Trial-1.5) or with BA alone were eligible, Of these groups, t hose patients in stable condition who returned for 6-month angiographic fol low-up formed the study population (n = 19, irradiated group and n = 11, co ntrol group). Endothelium-dependent coronary vasomotion was assessed by sel ective infusion of serial doses of acetylcholine (ACh) proximally to the tr eated area. Mean luminal diameter was calculated by quantitative coronary a ngiography both in the treated area and in distal segments. Endothelial dys function was defined as a vasoconstriction after the maximal dose of ACh (1 0(-6) mom), Seventeen irradiated segments (89.5%) demonstrated normal endot helial function. In contrast, 10 distal nonirradiated segments (53%) and 5 control segments (45%) demonstrated endothelium-dependent vasoconstriction (-19 +/- 17% and -9.0 +/- 5%, respectively), Mean percentage of change in m ean luminal diameter after ACh was significantly higher in irradiated segme nts (P = 0.01), Conclusions-Endothelium-dependent vasomotion of coronary segments treated w ith BA followed by beta-radiation is restored in the majority of stable pat ients at 6-month follow-up. This functional response appeared to be better than those documented both in the distal segments and in segments treated w ith BA alone.