Sr90 Treatment of Angiographic Restenosis - START

Apr 10, 2003
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Date Presented:
01/01/2000
Date Published:
01/01/2002
Date Updated:
04/10/2003
Original Posted Date:
04/10/2003
References

Description:

The goal of the Sr90 Treatment of Angiographic Restenosis Trial (START) was to evaluate the efficacy of intracoronary radiation with the use of Sr90/Y90 beta source for the treatment of in-stent restenosis.

Hypothesis:

Beta-radiation brachytherapy using the Novoste Betacath system can safely and effectively reduce restenosis rates.

Study Design

Study Design:

Patients Enrolled: 476
Mean Follow Up: 8 months
Mean Patient Age: mean age 61 years
Female: 34%
Mean Ejection Fraction: Mean 54.2% in the beta arm versus 54.6% in the placebo arm.

Patient Populations:

Single target site of in-stent restenosis in a native vessel between 2.7-4.0 mm; lesions <20 mm in length.

Exclusions:

Planned multivessel PCI, MI within prior 72 hours, unprotected left main coronary artery disease, two overlapping stents, prior history of any chest radiotherapy, or prior stent placement for in-stent restenosis.

Primary Endpoints:

Efficacy: TVR Safety: MACE (composite of death, MI, or TVR)

Drug/Procedures Used:

Patients with in-stent restenotic lesions underwent percutaneous coronary intervention (PCI) to obtain visual diameter stenosis <30%. Following PCI, patients were randomized to adjunctive treatment with Sr90/Y90 beta-radiation (n=244) or placebo (n=232) using a 30 mm (n=452) or 40 mm (n=24) BetaCath radioactive source train (Novoste Corp).

Concomitant Medications:

Aspirin (325 mg)

Principal Findings:

The primary end point of target vessel revascularization (TVR) by eight months was lower in the beta-radiation arm compared with placebo (17.0% vs. 26.8%, p=0.015). The major adverse cardiac events (MACE) composite of death, myocardial infarction (MI), or TVR also occurred less frequently in the beta arm than the placebo arm (19.1% vs. 28.7%, p=0.024). Beta-radiation was associated with reduced restenosis rates (in-stent 14.2% vs. 41.2% [p<0.001]; analysis segment 28.8% vs. 45.2% [p=0.001]). Lesion length at follow-up was shorter in the beta arm compared to the placebo arm (8.62 mm vs. 12.5 mm, p<0.001). Stent thrombosis occurred in one patient in each arm.

Interpretation:

Among patients undergoing successful PCI for in-stent restenosis, use of beta-radiation brachytherapy using the Novoste Betacath system was associated with a reduction in TVR and MACE at eight months. Additionally, angiographic restenosis rates were reduced in the beta-radiation arm, with no excess of stent thrombosis. This was the first randomized trial to show such a benefit with Sr90/Y90 beta-radiation. Prior studies have shown a benefit with gamma-radiation. However, gamma-radiation requires longer exposure times (3-5 minutes with beta-radiation vs. 20-30 minutes with gamma-radiation). Longer follow-up is needed to ascertain if restenosis was delayed and to ascertain if aneurysmal dilation occurs.

References:

Popma JJ, Suntharalingam M, Lansky AJ, et al. Randomized trial of 90Sr/90Y beta-radiation versus placebo control for treatment of in-stent restenosis. Circulation. 2002;106:1090-6. Initially reported at late-breaking trials, ACC 2000.

Keywords: Myocardial Infarction, Beta Particles, Follow-Up Studies, Thrombosis, Constriction, Pathologic, Brachytherapy, Stents, Percutaneous Coronary Intervention


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