Saphenous vein grafts have an 80-90% patency rate at 1 year, 70-85% patency rate between 1 and 5 years and 45-65% patency rate at 10 years. Thus, essentially half of all saphenous vein grafts occlude at 10 years. In addition, about half of all patent vein grafts at 10 years have significant atherosclerotic changes.

Understanding Saphenous Vein Graft Patency. Sabik et al. Circulation;124:273-275.

Long-term patency of saphenous vein and left internal mammary artery grafts after coronary artery bypass surgery. J Am Coll Cardiol. 2004;44(11):2149-2156.