Randomized Trial of 90Sr/90Y beta-Radiation Versus Placebo Control for Treatment of In-Stent Restenosis - Randomized Trial of 90Sr/90Y beta-Radiation Versus Placebo Control for Treatment of In-Stent Restenosis

Description:

The goal of this study was to evaluate the efficacy of intracoronary radiation with the use of a 90Sr/90Y beta-source for the treatment of in-stent restenosis.

Study Design

Study Design:

Patients Enrolled: 476

Drug/Procedures Used:

The study design was a randomized multicenter blinded trial of 476 patients with in-stent restenosis. Patients were randomly assigned to receive an intracoronary catheter containing either 90Sr/90Y (n=244) or placebo (n=232) sources. The dose 2 mm from the center of the source was 18.4 Gy for vessels between 2.70 - 3.35 mm in diameter and 23.0 Gy for vessels between 3.36 - 4.0 mm. The primary end point was clinically driven target-vessel revascularization by 8 months.

Principal Findings:

The primary end point was observed in 56 (26.8%) of the patients assigned to placebo and 39 (17.0%) of the patients assigned to radiation (P=0.015). The incidence of the composite endpoint of death, myocardial infarction, and target-vessel revascularization was 60 (28.7%) in the patients assigned to placebo and 44 (19.1%) in the patients assigned to radiation (P=0.024). Binary 8-month angiographic restenosis (50% diameter stenosis) within the entire segment treated with radiation was reduced from 45.2% in the placebo-treated patients to 28.8% in the 90Sr/90Y treated patients (P=0.001). Stent thromboses was seen infrequently and occurred in 1 patient assigned to placebo within 24 hours after the procedure and in 1 patient assigned to 90Sr/90Y at day 244.

Interpretation:

Among patients with in-stent restenosis, beta-radiation using 90Sr/90Y was associated with a reduction in the primary endpoint of clinically driven target vessel revascularization by 8 months. Likewise, binary angiographic restenosis was reduced. In stent restenosis remains a significant clinical problem with more than 100,000 patients treated for this condition each year. Previous trials have demonstrated that gamma radiation is effective in the treatment of in-stent restenosis with significant reductions in target vessel revascularization noted in several clinical trials. The START investigators have demonstrated that beta radiation also effectively reduces target vessel revascularization in patients with in-stent restenosis. An important consideration is that despite radiation, binary angiographic restenosis was still observed in > 28% of these patients. If the preliminary results from the drug-eluting stents are confirmed in larger trials, the role of radiation therapy in treating patients with in-stent restenosis will need to be reevaluated and compared with this new modality. If drug eluting stents are effective, the incidence of in stent restenosis will likewise be reduced. Very late follow-up of these patients remains to be reported at this time.

References:

Popma JJ, Suntharalingam M, Lansky AJ, et al for the Stents And Radiation Therapy (START) Investigators. Randomized Trial of 90Sr/90Y beta-Radiation Versus Placebo Control for Treatment of In-Stent Restenosis. Circulation 2002;106:1090-96.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Stable Ischemic Heart Disease, Chronic Angina

Keywords: Myocardial Infarction, Beta Particles, Follow-Up Studies, Coronary Restenosis, Thrombosis, Drug-Eluting Stents, Research Personnel, Constriction, Pathologic, Gamma Rays


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