The potential role of external venous supports in coronary artery bypass graft surgery.

Despite the apparent superiority of arterial conduits for coronary artery bypass grafting (CABG), the long saphenous vein remains the most commonly used graft. The high failure rate of long saphenous vein grafts (SVGs) over time is therefore an important limiting factor for the long-term outcomes of CABG. Various methods to improve SVG patency have been proposed, although few have had a significant impact on clinical practice. External SVG supports have been a focus of research over the past 50 years, with their use intended to minimize well-documented pathophysiological changes that occur in the SVG following implantation into the coronary circulation. These devices have been trialled extensively in animal models to assess their impact on both the morphology and the function of vascular conduits. Recently, a number of studies have been conducted in patients, leading to a substantial development in their design and the accumulation of a large body of evidence attesting to their potential benefit in CABG. In this review, we briefly discuss the proposed mechanism of action of external SVG supports and then evaluate the results from animal studies and more recent research assessing their use in CABG patients. Finally, we conclude that newer models of external stents have the potential to improve long-term outcomes in SVG.