BACKGROUND: Abnormal endothelium-dependent coronary vasomotion has been
reported after balloon angioplasty (BA), as well as after intracoronary
radiation. 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 segments treated with BA and brachytherapy. METHODS AND RESULTS:
Patients with single de novo lesions treated either with BA followed by
intracoronary beta-irradiation (according to the Beta Energy Restenosis
Trial-1.5) or with BA alone were eligible. Of these groups, those patients
in stable condition who returned for 6-month angiographic follow-up formed
the study population (n=19, irradiated group and n=11, control group).
Endothelium-dependent coronary vasomotion was assessed by selective
infusion of serial doses of acetylcholine (ACh) proximally to the treated
area. Mean luminal diameter was calculated by quantitative coronary
angiography both in the treated area and in distal segments. Endothelial
dysfunction was defined as a vasoconstriction after the maximal dose of
ACh (10(-6) mol/L). Seventeen irradiated segments (89.5%) demonstrated
normal endothelial 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 mean luminal diameter after ACh was significantly higher in
irradiated segments (P=0.01). CONCLUSIONS: Endothelium-dependent
vasomotion of coronary segments treated with BA followed by beta-radiation
is restored in the majority of stabl