The SOS (Stenting Of Saphenous Vein Grafts) Trial

Introduction: The prevalence of coronary artery bypass graft (CABG) surgery is high in the veteran population. Saphenous veins are used as conduits in the majority of CABG operations. Compared to arterial conduits, saphenous vein grafts (SVGs) have a high rate of failure, requiring percutaneous coronary intervention (PCI) or repeat CABG. Bare metal stents are currently used in the majority of PCI in SVGs because they increase the procedural success rate and decrease restenosis. However, even with the use of bare metal stents, restenosis still occurs in 37-53% of the SVGs, often requiring repeat target vein graft revascularization.

Drug-eluting stents (DES) have been a major breakthrough in percutaneous coronary intervention because they significantly reduce the incidence of in-stent restenosis in de novo lesions of native coronary arteries. Even though, no randomized controlled trials have compared DES with bare stents in SVG interventions, DES are increasingly being used off label in this setting, based on registry data. DES are expensive and may not provide benefit in SVGs since the atherosclerotic process is different in SVGs and in native coronary arteries. We propose to compare the 12-month angiographic restenosis rates after implantation of a polymer-based paclitaxel-eluting stent or the Express-2 bare metal stent (which is identical to the paclitaxel-eluting stent but has no drug coating) in saphenous vein graft lesions.

Hypothesis: Compared to implantation of a bare metal stent, implantation of a similar paclitaxel-eluting stent (Taxus™, Boston Scientific, Nattick, Massachusetts) in saphenous vein graft lesion will reduce the incidence of angiographic in-stent restenosis after 12 months.

Specific objectives: We propose to randomize patients undergoing stenting of a saphenous vein graft lesion to a bare metal stent or an identical paclitaxel-eluting stent (Taxus™) in order to determine:

• whether the paclitaxel-eluting stent will reduce the incidence of binary angiographic in-stent restenosis, as assessed by 12-month follow-up quantitative coronary angiography (primary study endpoint), and
• whether the paclitaxel-eluting stent will reduce the 24-month incidence of ischemia-driven target vessel revascularization, target vessel failure, overall major adverse cardiac and cerebrovascular events, and intra-stent intimal hyperplasia accumulation, as measured by intravascular ultrasound (secondary endpoints).

Inclusion criteria

• at least one 50-99% de-novo or restenotic lesion in a saphenous vein graft that is between 2.5 and 4.0 mm in diameter, requiring percutaneous coronary intervention according to the opinion of the attending cardiologist
• willing to return for repeat coronary angiography after 12 months
• able to give informed consent

Exclusion criteria

• previous or planned use of intravascular brachytherapy in the target vessel
• a left ventricular ejection fraction of less than 25 percent
• hemorrhagic diatheses
• contraindications or allergy to aspirin, thienopyridines, paclitaxel, or stainless steel
• a history of anaphylaxis in response to iodinated contrast medium
• use of paclitaxel within 12 months before study entry or current use of colchicine
• a serum creatinine level of more than 2.0 mg per deciliter (177 µmol per liter)
• a leukocyte count of less than 3500 per cubic millimeter, or a platelet count of less than 100,000 per cubic millimeter
• a recent positive pregnancy test, breast-feeding, or the possibility of a future pregnancy
• coexisting conditions that limit life expectancy to less than 24 months or that could affect a patient's compliance with the protocol