“…Historically, the 2 main options for cerebral bypass grafts have been the radial artery (RA) and the saphenous vein. 2,12,29 While there are advantages and disadvantages to both, RA grafts are generally preferred for EC-IC bypass given their higher overall patency rates and better donor-recipient vessel size matching. Nonetheless, RA grafts are at risk for spasm, an extreme smooth muscle-mediated vasoconstrictive response to mechanical or pharmacological stimuli, which can occur in up to 10% of cases.…”