Arterial grafts, such as the internal mammary artery, have several advantages over vein grafts. Arterial grafts tend to stay open longer and have higher patency rates, meaning they are less likely to become blocked over time, compared to vein grafts. This can result in improved long-term survival and reduced need for repeat procedures. Arterial grafts also have better resistance to atherosclerosis and can provide better blood flow to the heart muscle, leading to improved outcomes.