Vasospasm sometimes disturbs successful blood access for hemodialysis, and prevention of vasospasm is desirable when constructing arteriovenous fistulae. We first investigated vasospasm of the radial artery in this operation and analyzed factors associated with this phenomenon in 20 patients with end-stage renal disease. Alteration of blood flow in the radial artery was evaluated in them, and intima-media thickness (IMT), endothelial function index (EFI) and laboratory data were analyzed. Vasospasm occurred in 9 of 20 cases (45.0%) at 5 min after anastomosis, and displayed a marginally significant correlation (r=0.31, p=0.081) with EFI. We then conducted a randomized study of 84 patients with end-stage renal disease to examine the effects of administering transdermal glyceryl trinitrate (GTN) in this operation. EFI was significantly correlated with IMT (r= -0.45, p<0.001). At 5 min after anastomosis, vasospasm occurred in 12 (28.6%) of 42 patients who were administered GTN, while it occurred in 20 (47.6%) of 42 patients without GTN administration (controls); the difference was marginally significant (p=0.072). In patients with IMT≤1.1, alteration of diameter (5 min/1 min after anastomosis) was significantly reduced compared with controls (p=0.032). These data suggest that IMT could offer a predictor of vasospasm occurrence during arteriovenous fistula operations. Use of preoperative transdermal GTN may be effective in preventing vasospasm during such surgery.