Evaluation in vivo of the endothelial function of the native gastroepiploic artery.

The endothelial function of a coronary bypass graft is an important aspect, contributing not only to its patency but to its functional performance. To evaluate this aspect in vivo, we studied 16 patients who underwent 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, and after 2 mg isosorbide dinitrate injection directly into the GEA. Mean GEA diameter was 2.02 +/- 0.38 mm at baseline. We observed dose-dependent vasodilation during acetylcholine infusion: The mean diameter increased slightly to 2.11 +/- 0.32 mm (+6%, not significant) with the second dosage and, more significantly, with the highest dosage, to 2.32 +/- 0.33 mm (+18%, p < 0.001). More important vasodilation was observed after administration of nitrates (+36%, p < 0.001). We found no difference between patients with and without coronary artery disease and no relationship with risk factors for atherosclerosis. A positive correlation was seen between the vasodilation observed after nitrate administration 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 response to acetylcholine, reflecting preserved endothelial function. This sensitivity should affect favorably the hemodynamic performance of grafts performed with GEA, as well as these grafts' long-term patency rate.