Paclitaxel-Eluting Stents vs. Brachytherapy for In-Stent Restenosis - TAXUS V ISR

Description:

The goal of the trial was to evaluate treatment with paclitaxel-eluting stents compared with vascular brachytherapy (VBT) among patients with restenotic coronary lesions.

Study Design

Study Design:

Patients Enrolled: 396
Mean Follow Up: 9 months
Mean Patient Age: Median age 63 years
Female: 34

Patient Populations:

Age ≥18 years with stable or unstable angina or inducible ischemia undergoing percutaneous coronary intervention (PCI) of a single bare-metal ISR lesion in a native coronary artery

Exclusions:

Previous or planned use of VBT, external beam radiotherapy, or any antirestenotic drug-eluting stent in the target vessel; ataxia-telangiectasia or other known genetic radiation sensitivity disorders; myocardial infarction within 72 hours or creatine kinase-MB level >2 times the upper limit of normal; left ventricular ejection fraction <25%; stroke within 6 months; planned coronary artery bypass graft surgery within 9 months; hemorrhagic diatheses or contraindications or allergy to aspirin, thienopyridines, paclitaxel, stainless steel, or anaphylaxis to iodinated contrast; current or future warfarin use anticipated within 6 months of the procedure; chemotherapy within 12 months, or planned use of paclitaxel, rapamycin, or colchicines within 9 months; serum creatinine level >2.0 mg/dl, leukocyte count <3500/μL or platelet count <100,000 or >750,000; woman of child-bearing potential without a recent negative pregnancy test or lactating; man or woman with planned procreation within 3 months; comorbid conditions limiting life expectancy to <24 months or that could affect protocol adherence; planned procedure requiring antiplatelet therapy withdrawal within 6 months; and current participation in other investigational trials

Primary Endpoints:

Ischemia-driven TVR at 9 months

Drug/Procedures Used:

Patients were randomized to angioplasty followed by VBT using a beta-source (n = 201) or to PCI with paclitaxel-eluting stents (n = 195). Patients underwent repeat angiography at 9 months.

Principal Findings:

Median time since bare-metal stent implantation was 316 days in the VBT group and 281 days in the paclitaxel group (p = 0.43). Target lesion was left anterior descending in 33.3% of the VBT group and 39.2% of the paclitaxel group. Stenosis at baseline was ~68% in each group, with a median lesion length of ~15 mm. The restenosis pattern was diffuse in 47.0% of the VBT group and 60.8% of the paclitaxel group, and was focal in 29.0% and 18.6%, respectively. Final post-procedure diameter stenosis in the analysis segment was 29.3% with VBT and 20.6% in the paclitaxel group (p < 0 .001).

The primary endpoint of ischemic target vessel revascularization (TVR) at 9 months was lower in the paclitaxel group compared with VBT (10.5% vs. 17.5%, p = 0.046). The composite of any major adverse cardiac event (MACE) was also lower in the paclitaxel group (11.5% vs. 20.1%, p = 0.02), although this was primarily driven by the reduction in TVR, with no difference in death (n = 0 vs. n = 1) or myocardial infarction (3.7% vs. 4.6%, respectively). There was one case of target vessel thrombosis in each group post-discharge through 1 month, and two in the paclitaxel group and three in the VBT group from 1 month through 6 months.

Angiographic follow-up at 9 months showed a smaller minimum lumen diameter in the VBT group in the analysis segment (1.55 mm vs. 1.99 mm, p < 0.001), as well as a higher rate of binary restenosis with VBT (31.2% vs. 14.5%, p < 0.001).

Interpretation:

Among patients with restenotic coronary lesions, treatment with paclitaxel-eluting stents was associated with a reduction in ischemic-driven TVR at 9 months compared with VBT.

Intravascular brachytherapy is the only currently approved treatment for in-stent restenosis (ISR). However, brachytherapy is complicated to perform and is only undertaken at a limited number of sites. While not approved for ISR, drug-eluting stents have been used for the treatment of ISR and the present study is now the second large-scale randomized trial to show superiority with drug-eluting stents over VBT for treatment of ISR.

The SISR study evaluated brachytherapy compared with sirolimus-eluting stents for ISR treatment, and showed a reduction in target vessel failure with sirolimus-eluting stents.

References:

Presented by Dr. Gregg W. Stone at the March 2006 ACC Annual Scientific Session, Atlanta, GA.

Stone GW, Ellis SG, O'Shaughnessy CD, et al. Paclitaxel-eluting stents vs vascular brachytherapy for in-stent restenosis within bare-metal stents: the TAXUS V ISR randomized trial. JAMA 2006;295:1253-63.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Stable Ischemic Heart Disease, Atherosclerotic Disease (CAD/PAD), Interventions and Coronary Artery Disease, Chronic Angina

Keywords: Coronary Artery Disease, Myocardial Infarction, Follow-Up Studies, Coronary Restenosis, Drug-Eluting Stents, Sirolimus, Constriction, Pathologic, Angioplasty, Percutaneous Coronary Intervention, Paclitaxel, Metals, Thrombosis, Brachytherapy


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