Follow-up and surveillance of vein grafts: when and how to intervene to prevent complications.

Despite advances in endovascular strategies, surgical infrainguinal lower limb revascularization remains the gold standard treatment for critical lower limb ischemia and disabling claudication. Maintaining patency of infrainguinal vein bypass grafts has been a challenging task for vascular surgeons as they are prone to developing stenoses which may precipitate failure of the bypass. Duplex ultrasound scanning has evolved as the investigation of choice to identify vein graft lesions but graft surveillance programs using this technique remain controversial. The rationale for graft surveillance is that intervention in a patent but failing graft results in improved long-term patency and limb salvage rates compared to rescue of an occluded graft. The six-week postoperative Duplex ultrasound scan is important in identifying flow abnormalities that can predict the natural history of a vein graft and the outlook for the limb in the medium term. There are multiple factors influencing vein graft failure, which means guidelines should be flexible in terms of when and which type of intervention to the graft is optimum. Patency and durability favour open surgical revision over endovascular intervention but this must be counter balanced by the increased morbidity associated with surgical revision.