The Best Stent for Saphenous Vein Grafts Is?
Abstract & Commentary
By Michael H. Crawford, MD, Professor of Medicine, and Chief of Clinical Cardiology, at the University of California, San Francisco. Dr. Crawford is on the speaker's bureau for Pfizer.
Source: Vermeersch P, et al. Randomized Double-Blind Comparison of Sirolimus-Eluting Stent vs Bare-Metal Stent Implantation in Diseased Saphenous Vein Grafts. J Am Coll Cardiol 2006;48:2421-2431
After 8-10 years, atherosclerosis of saphenous vein grafts and symptoms of ischemia are common. Since repeat bypass surgery is associated with a higher mortality than first surgeries, percutaneous interventions (PCI) are preferred for vein graft disease. Bare metal stents (BMS) have a higher rate of restenosis, exceeding 30%, in vein grafts as compared to the native circulation. Thus, Vermeersch and colleagues hypothesized that sirolimus-eluting stents (SES) may be superior for vein graft disease and organized the Reduction of Restenosis in Saphenous vein grafts with Cypher sirolimus-eluting stent (RRISC) trial, which randomized patients with symptomatic vein graft disease to BMS or SES. Exclusion criteria included recent myocardial infarction, left ventricular ejection fraction < 25%, creatinine > 3.0 mg/dl, totally occluded grafts and previous brachytherapy. Distal protection and glycoprotein IIb/IIIa were strongly recommended during the procedure. All patients had repeat angiography with intra vascular ultrasound (IVUS) at 6 months. The angiograms and IVUS were analyzed quantitatively. The primary endpoint was 6-month in-stent late lumen loss. Several secondary angiographic, IVUS and clinical endpoints were also assessed. The study was done at a single center without industry support.
Results: The study enrolled 75 patients with 96 lesions in 80 vein grafts. In-stent late lumen loss was less with SES vs BMS (0.38 mm vs 0.79 mm, respectively, P = 0.001). Binary in-stent restenosis (% with > 50% lesion) was reduced by SES (11% vs 31%, P = 0.02) as was binary in-segment restenosis (14% vs 44%, P = 0.03). IVUS neointimal volume was less with SES (1 vs 24 mm3, P > 0.001). Target lesion revascularization was less with SES (5% vs 27% P = 0.01). Death and myocardial infarction were not different. The authors concluded that SES significantly reduced 6-month lumen loss as compared to BMS with a corresponding reduction in repeat revascularization procedures.
Commentary
This is the first prospective randomized trial of drug-eluting stent vs BMS in occlusive saphenous vein graft disease. The major weakness of the study was the small number of patients in this single-center study, which left it underpowered for clinical outcomes. However, it was designed as a 6-month angiographic study and has several strengths. It was not industry sponsored even though only one brand of stents was used. Almost all the patients actually had their 6-month study. IVUS was used. The methodology was strong, especially their blinding technique.
The results clearly show superior 6-month outcomes with the dug-eluting stent. Prior studies of BMS vs balloon angioplasty alone have not consistently shown any advantage to stenting, so these results are clearly welcome news. However, the major remaining issue is long-term results, especially late in-stent thrombosis or restenosis. This will have to await further studies. Another issue is that the patients only received clopidogrel for 2 months. This exceeds FDA recommendations, but may not be long enough in light of new data on late thrombosis. In addition, certain exclusion criteria leave the use of drug-eluting stents in saphenous vein grafts up in the air for certain patients; large vein grafts (> 4 mm), distal vein graft disease, and acute myocardial infarction due to saphenous vein disease. These issues also await further study. At this time many laboratories are deploying drug-eluting stents in saphenous veins when sizing isn't an issue, even though this is an off-label use, based upon this study and other encouraging data. This seems justified given the impressive short-term results in these challenging patients.
After 8-10 years, atherosclerosis of saphenous vein grafts and symptoms of ischemia are common. Since repeat bypass surgery is associated with a higher mortality than first surgeries, percutaneous interventions (PCI) are preferred for vein graft disease.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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