Prostacyclin production by different human grafts employed in coronary operations

Segments of human saphenous vein, internal mammary artery, right gastroepiploic artery, and inferior epigastric artery were incubated in vitro in Krebs-Henseleit solution and compared in terms of their capacity to generate and release into the medium 6-keto-prostaglandin F_1α (PGF_1α), the stable metabolite of prostacyclin. The four vascular conduits were also challenged with endothelin-1 (40 ng/mL), and accumulation of the lipidic material in the bathing fluid was also studied. The results obtained show clearly that under both normal and endothelin-1-stimulated conditions, the four vascular segments generate a substantial amount of 6-keto-PGF_1α. Multiple-comparisons analysis of the results indicates that the rank order in producing 6-keto-PGF_1α is as follows: inferior epigastric artery > internal mammary artery > right gastroepiploic artery > saphenous vein (p <0.01). A similar order of potency was obtained in vascular conduits stimulated with endothelin-1. The rate of formation of immunoreactive 6-keto-PGF_1α under both normal and stimulated conditions by the inferior epigastric artery (normal, 301 ± 8 pg/mg of tissue; stimulated, 519 ± 13 pg/mg of tissue) was at 10 minutes more than 2 times (p <0.01) that of the saphenous vein and about 1.5 times (p <0.01) that of the right gastroepiploic artery. In conclusion, the fact that the endothelium of the inferior epigastric artery has a better capacity to generate prostacyclin compared with the other vascular segments considered may have some relevance with respect to its resistance to atherosclerosis and its patency rate and may indicate this arterial conduit is a good alternative graft in myocardial revascularization.