Coronary Endothelial Dysfunction Distal to Stent of First-Generation Drug-Eluting Stents

ObjectivesThis study sought to evaluate the relationship between coronary endothelial function and neointimal coverage after drug-eluting stent (DES) implantation.BackgroundThe mechanisms of endothelial dysfunction after DES implantation remain to be fully elucidated. We hypothesized that poor neointimal coverage after DES implantation may be associated with endothelial dysfunction distal to the stent site.MethodsSixty-six stable angina patients treated with a first-generation DES were enrolled. At 9-month follow-up, coronary endothelial function was evaluated with intracoronary infusion of incremental doses of acetylcholine (10−8, 10−7, and 10−6 mol/l) and nitroglycerin (200 μg). Vascular responses at the segments proximal and distal to the stent site were angiographically and quantitatively measured. At the same time, the degree of neointimal coverage was evaluated using coronary angioscopy and classified into 4 grades: 0 (no coverage) to 3 (full coverage).ResultsWe divided the subjects into poor-coverage (grades 0 to 1, n = 33) and good-coverage (grades 2 to 3, n = 33) groups. Acetylcholine induced dose-dependent coronary vasoconstrictions in both groups. At the segment distal to the stent, the magnitude of vasoconstriction to acetylcholine in the poor-coverage group was significantly greater than in the good-coverage group (p < 0.001), whereas vasomotor responses proximal to the stent and vasodilation by nitroglycerine were similar between the 2 groups.ConclusionsCoronary endothelial dysfunction distal to the stent was associated with poor neointimal coverage after DES implantation.