The use of drug-eluting stents in venous coronary artery bypass grafts.

Saphenous vein grafts (SVG) frequently develop atherosclerotic disease that may result in stenosis or occlusion. Percutaneous coronary intervention (PCI) of SVG is associated with a relatively high-risk of procedural complications (due mainly to distal embolisation) and restenosis rates, that along with accelerated atherosclerotic disease progression, result in a poor mid-term outcome. The role of drug-eluting stents (DES) in improving clinical results of PCI in SVG has not yet been established. Current information is limited and based on several retrospective uncontrolled cohort studies comparing DES and bare metal stents (BMS), two matched case-control studies and two prospective, very small size single-centre trials (RRISC, SOS) designed for 6-month angiographic endpoints, but underpowered for clinical events. Most studies with a short follow-up reported a significant reduction in target vessel revascularisation (TVR) in the DES-treated group, but for those with longer follow-up periods, the differences were either smaller or non-significant. Regarding safety, only the DELAYED RRISC trial reported a significant increased in stent thrombosis and death rates, while no increase in mortality was observed in any other. In fact, in two studies a trend towards a lower mortality rate was detected. In light of the actual data, and until more evidence has been provided by properly sized, multicentre prospective, randomised trials (which not even ongoing yet), we may assume that DES decrease short-term TVR rates as they do in native vessels, but that their impact on clinical events after one year is weak and inconsistent. Although unproven, the increase in mortality reported in one single trial supports a cautious approach towards the use of DES in SVG. Whether specific stent platforms, polymers or drugs are more appropriate in SVG lesions has not been addressed at this time.