After the creation of an autogenous lower extremity bypass graft, the vein must undergo a series of dynamic structural changes to stabilize the arterial hemodynamic forces. These changes, which are commonly referred to as remodeling, include an inflammatory response, the development of a neointima, matrix turnover, and cellular proliferation and apoptosis. The sum total of these processes results in dramatic alterations in the physical and biomechanical attributes of the arterialized vein. The most clinically obvious and easily measured of these is lumen remodeling of the graft. However, although somewhat less precise, wall thickness, matrix composition, and endothelial changes can be measured in vivo within the healing vein graft. Recent translational work has demonstrated the clinical relevance of remodeling as it relates to vein graft patency and the systemic factors influencing it. By correlating histologic and molecular changes in the vein, insights into potential therapeutic strategies to prevent bypass failure and areas for future investigation are explored.Clinical Relevance:
The autogenous vein bypass graft remains the gold standard revascularization method for the ischemic limb. Newly implanted vein grafts undergo dramatic structural changes in response to the new high-flow, high-pressure environment. These changes, which are commonly referred to as remodeling, include a pronounced inflammatory response accompanied by the development of a neointima and significant changes in matrix composition. Similar to how maturation of arm veins predicts the performance of an arteriovenous fistula, recent translational work has demonstrated that remodeling of the vein graft is important for subsequent patency of the lower extremity bypass graft.