If the radial artery is being accessed then it may be necessary to shave the area prior to starting the procedure. Contrast dye is used during a coronary angiogram, and it is important to know if the patient has any allergies to contrast dye. The procedure may be done through the femoral artery in the groin but may also be done through the radial artery in the forearm. Numbness distal to the incision can be a sign of internal bleeding from the artery that was accessed and is abnormal.