Reduction of vasoconstriction by removing periarterial nerve in human gastroepiploic artery imply prevention of vasospasm

Background The right gastroepiploic artery (GEA) is used as an in‐situ arterial graft for coronary artery bypass grafting (CABG). However, the GEA is more likely to cause vasospasms compared to the internal thoracic artery. We hypothesized that the significant cause of GEA spasms is triggered by periarterial sympathetic nerve, since the GEA is classified as a muscular artery. Materials and Methods Unused parts of the GEA were obtained from patients who underwent CABG. The vessel was assigned to control (N+) and denervation (N−) group. For N− group, periarterial nerve was microscopically removed. These vessels were investigated by hematoxylin‐eosin (H‐E) and immunohistochemical staining. Then, each vessel was exposed to electrical field stimulation (EFS). Results Histological analysis revealed that the periarterial connective tissues including neuropeptide Y (NPY) were removed from lateral layer to external elastic membrane in the N−, whereas they were preserved in N+. The vasoconstriction by EFS with serial frequency was consistently lower in N− than N+ (p<0.05 at 20 and 50Hz; n=8 each). These vasoconstrictions were inhibited by tetrodotoxin. Moreover, endothelium dependent relaxation and vasoconstriction of the smooth muscle were similar in both groups. Conclusions The removal of periarterial nerves from human GEA can prevent graft spasms without disturbance of endothelial and smooth muscle functions.