April 18, 2002Open Access
View Full PaperIntravascular Gamma Radiation for In-Stent Restenosis in Saphenous-Vein Bypass Grafts
Key Result
Intravascular gamma radiation reduced the 12-month rate of major cardiac events compared to placebo (32% vs. 63%, P<0.001) in patients with in-stent restenosis of saphenous-vein bypass grafts.
Study Design
Type
RCT (n=120)
Blinding
Double-blind
Randomization
Randomized
Structured PICO
Does intravascular gamma radiation reduce the composite of cardiac death, Q-wave MI, or target vessel revascularization in patients with in-stent restenosis of saphenous-vein bypass grafts?
P
Population
120 patients with in-stent restenosis in saphenous-vein grafts (majority with diffuse lesions) who underwent successful balloon angioplasty, atherectomy, additional stenting, or a combination of these procedures
I
Intervention
Intravascular gamma radiation with a ribbon containing iridium-192 (dose of 14 to 15 Gy in vessels 2.5 to 4.0 mm in diameter and 18 Gy in vessels >4.0 mm in diameter)
C
Comparator
Intravascular treatment with a ribbon containing nonradioactive seeds (placebo)
O
Outcome
Death from cardiac causes, Q-wave myocardial infarction, revascularization of the target vessel, and a composite of these events at 12 monthscomposite
Intravascular gamma radiation significantly reduces the rate of major cardiac events and target lesion revascularization in patients with in-stent restenosis of saphenous-vein bypass grafts.
Main Result
Absolute Event Rate: 32% vs 63%
p-value: p=<0.001
Abstract
BACKGROUND: Intracoronary radiation therapy is effective in reducing the recurrence of in-stent stenosis in native coronary arteries. We examined the effects of intravascular gamma radiation in patients with in-stent restenosis of saphenous-vein bypass grafts. METHODS: A total of 120 patients with in-stent restenosis in saphenous-vein grafts, the majority of whom had diffuse lesions, underwent balloon angioplasty, atherectomy, additional stenting, or a combination of these procedures. If the intervention was successful, the patients were randomly assigned in a double-blind fashion to intravascular treatment with a ribbon containing either iridium-192 or nonradioactive seeds. The prescribed dose, delivered at a distance of 2 mm from the source, was 14 to 15 Gy in vessels that were 2.5 to 4.0 mm in diameter and 18 Gy in vessels with a diameter that exceeded 4.0 mm. The primary end points were death from cardiac causes, Q-wave myocardial infarction, revascularization of the target vessel, and a composite of these events at 12 months. RESULTS: Revascularization and radiation therapy were successfully accomplished in all patients. At six months, the restenosis rate was lower in the 60 patients assigned to the iridium-192 group than in the 60 assigned to the placebo group (21 percent vs. 44 percent, P=0.005). At 12 months, the rate of revascularization of the target lesion was 70 percent lower in the iridium-192 group than in the placebo group (17 percent vs. 57 percent, P<0.001), and the rate of major cardiac events was 49 percent lower (32 percent vs. 63 percent, P<0.001). CONCLUSIONS: The results of our study support the use of gamma-radiation therapy for the treatment of in-stent restenosis in patients with bypass grafts.