EVALUATION IN-VIVO OF THE ENDOTHELIAL FUNCTION OF THE NATIVE GASTROEPIPLOIC ARTERY

The endothelial function of a coronary bypass graft is an important as pect, contributing not only to its potency but to its functional perfo rmance. To evaluate this aspect in vivo, we studied 16 patients who un derwent selective catheterization of the native gastroepiploic artery (GEA). Quantitative angiography of the GEA was performed at baseline, after 2 minutes' infusion of acetylcholine in three ascending doses, a nd after 2 mg isosorbide dinitrate injection directly into the GEA. Me an GEA diameter was 2.02 +/- 0.38 mm at baseline. We observed dose-dep endent vasodilation during acetylcholine infusion: The mean diameter i ncreased slightly to 2.11 +/- 0.32 mm (+6%, not significant) with the second dosage and, more significantly, with the highest dosage, to 2.3 2 +/- 0.33 mm (+18%, p < 0.001). More important vasodilation was obser ved after administration of nitrates (+36%, p < 0.001). We found no di fference between patients with and without coronary artery disease and no relationship with risk factors for atherosclerosis. A positive cor relation was seen between the vasodilation observed after nitrate admi nistration and the highest dose of acetylcholine (r = 0.728, p = 0.002 ). In conclusion, the GEA demonstrates a notable vasodilatory response to nitrates (non-endothelium-dependent) and a dose-related dilator re sponse to acetylcholine, reflecting preserved endothelial function. Th is sensitivity should affect favorably the hemodynamic performance of grafts performed with GEA, as well as these grafts' long-term potency rate.