Insights into the pathogenesis of vein graft disease: lessons from intravascular ultrasound

The success of coronary artery bypass grafting (CABG), although the gold standard for the treatment of multivessel coronary artery disease, is limited by poor long-term vein graft patency [1]. Early vein graft thrombosis (within 1 month) occurs in up to 15% of vein grafts due to graft spasm or technical error [2,3], whilst late vein graft failure occurs as a consequence of early neointimal hyperplasia with later superimposed atheroma, so called 'vein graft disease' [1,4] and as many as 50% of all vein grafts are occluded at 10 years post surgery [5,6]. Despite the superiority of arterial graft patency over that of vein grafts, the multivessel nature of coronary artery disease and ready availability of saphenous vein still result in its use in over 70% of CABG procedures [7]. The alternative treatment modality for multivessel coronary atheroma, percutaneous coronary artery angioplasty and stenting (PCI), has traditionally suffered from even worse long-term results compared to CABG, due to high early restenosis rates; over 30% within 1 year [8]. This results in more frequent and more rapid return of symptoms and major adverse cardiac events (MACE) with PCI compared to CABG, necessitating more repeat revascularisation procedures [8]. The apparent success of new drug eluting stents has challenged this paradigm however. Rapamycin (a macrolide antibiotic) and the taxane, paclitaxel, two agents with potent antiproliferative properties, eluted from intracoronary stents, have dramatically reduced restenosis rates, MACE and reintervention rates in clinical trials [9,10], to the point where the superiority of CABG is now being seriously challenged [11]. This represents the clinical application of intensive research into the mechanisms of atherosclerosis and restenosis and strategies for their prevention over the last decade. Conversely, CABG has suffered from its apparent success, and with some exceptions [12], there have been comparatively few attempts to prevent or inhibit t