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Brachytherapy for SVG In-Stent Restenosis

One-year results show promise for radiation therapy in saphenous-vein bypass grafts.

In-stent restenosis recurrence after PCI is even more common in saphenous vein grafts (SVGs) than in native coronary arteries, but the effectiveness of brachytherapy has been established only in the latter. These investigators conducted a multicenter study to determine whether intravascular gamma-radiation (iridium-192) reduces restenosis recurrence in SVGs. Two of the investigators do consulting in this field; 1 holds radiation-therapy patents.

Subjects were 120 patients with in-stent restenosis in SVGs; most had a diffuse restenosis pattern, and 60% had already received >1 treatment for in-stent restenosis. Randomization was either to dummy seeds or to intravascular radiation (doses: 14 to 15 Gy at 2 mm for vessels 2.5 to 4.0 mm in diameter; 18 Gy at 2 mm for vessels with diameters >4.0 mm).

Six-month angiography was performed in 87% of patients. Minimum lumen diameter was significantly greater in irradiated patients than in placebo patients (mean, 1.92 vs. 1.32 mm). The 6-month restenosis rate was correspondingly lower with radiation (21% vs. 44%), resulting in a lower 12-month rate of target-vessel revascularization (28% vs. 62%). Only 1 radiation recipient (vs. 3 placebo patients) developed late thrombosis, despite additional stenting in 50% of patients overall.

Comment: This study extends the benefits of vascular brachytherapy for in-stent restenosis to SVG conduits. The results were as good, if not better, than those observed in native coronary arteries. We now have an important therapeutic alternative for a challenging clinical problem.

— Howard C. Herrmann, MD

Published in Journal Watch Cardiology June 7, 2002

Citation(s):

Waksman R et al. Intravascular gamma radiation for in-stent restenosis in saphenous-vein bypass grafts. N Engl J Med 2002 Apr 18; 346:1194-9.

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