Understanding Saphenous Vein Graft Patency

Saphenous vein was the conduit used in the first series of coronary surgery, and, with the exception of revascularization of the left anterior descending coronary artery, it remains the most commonly used conduit.1 There are several reasons for this. First, because of its relatively large diameter and wall characteristics, it is technically easy to use; second, it is plentiful, and therefore can be used to perform multiple grafts; third, it is long and can reach any coronary artery; and fourth, it is easily harvested. However, its durability and longevity are not ideal. One year after coronary surgery, 10% to 20% of saphenous vein grafts fail.2–4 From 1 to 5 years, an additional 5% to 10% fail, and from 6 to 10 years, an additional 20% to 25% fail.5 At 10 years, only about half of saphenous vein grafts are patent, and of those, only half are free of angiographic arteriosclerosis.6Article see p 280Saphenous vein graft failure during the first year of surgery is due to technical errors, thrombosis, and intimal hyperplasia. All saphenous vein grafts experience endothelial damage during harvesting and initial exposure to arterial pressure. This intimal injury leads to platelet adherence that may result in graft thrombosis and acute occlusion. Platelet adherence to the intimal surface is also the initial event in the development of intimal hyperplasia. After adhering to the intima, platelets release mitogenic proteins, stimulating smooth muscle cell migration, resulting in intimal proliferation and hyperplasia.7–11 After a year from surgery, arteriosclerosis is responsible for further saphenous vein graft failure.12,13 Mural thrombi and intimal hyperplasia are the early stages of vein graft arteriosclerosis.4,12 With time, lipid becomes incorporated in these areas of intimal hyperplasia, resulting in arteriosclerotic plaque, and eventual …