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Drug-Eluting Stents vs. Brachytherapy for Bare-Metal In-Stent Restenosis

Both paclitaxel- and sirolimus-eluting stents beat ionizing radiation.

Restenosis rates after percutaneous coronary intervention (PCI) are lower when drug-eluting stents (DES) have been used rather than bare-metal stents (BMS). In two new trials, researchers tested DES implantation in patients who had in-stent restenosis (ISR) after BMS placement. Both trials, funded by DES manufacturers, were randomized comparisons with vascular brachytherapy, the only FDA-approved treatment for ISR.

In the TAXUS V ISR trial, 396 patients with BMS ISR were randomized to undergo brachytherapy with a ß-emitting source or paclitaxel-eluting stent placement. Most patients had diffuse or proliferative restenotic lesions; 35% had diabetes. Crossover to stenting was required in 11% of brachytherapy patients. By 9 months, fewer DES recipients than brachytherapy recipients required revascularization for an ischemic target vessel (10.5% vs. 17.5%), even after adjustment for baseline differences between the groups (odds ratio, 0.52; P=0.04). Angiographic follow-up, obtained in 86% of patients at 9 months, revealed a trend toward less late loss in luminal diameter in the stent group and, consequently, a lower rate of binary restenosis with stenting than with brachytherapy (15% vs. 31%; P<0.001).

In the SISR trial, 384 patients with BMS ISR (32% with diabetes) were randomized in a 1:2 ratio to undergo brachytherapy (ß or ) or sirolimus-eluting stent placement. The groups had similar baseline clinical and angiographic characteristics, with a lesion profile similar to that in TAXUS V ISR. Angiography at 6 months revealed similar late loss in luminal diameter in the two groups, but significantly better net gain with stenting than with brachytherapy, due largely to better acute gain. Compared with brachytherapy, stenting achieved a trend toward a lower rate of binary angiographic restenosis at 6 months (20% vs. 30%; P=0.07) and a significantly lower rate of clinical target-vessel failure at 9 months (12% vs. 22%; P=0.02).

Comment: For in-stent restenosis after bare-metal stent implantation, paclitaxel-eluting and sirolimus-eluting stents both performed better than vascular brachytherapy. Mechanisms for the advantage include achievement of larger luminal diameters (through greater acute gain and comparable or less late loss) and no radiation-associated edge effects. Given these findings and the expense and logistical difficulties of brachytherapy, that treatment likely will continue to lose favor. Nonetheless, we need longer-term follow-up after DES implantation for ISR, to document rates of late thrombosis and of potential late catch-up restenosis. As the editorialists note, given the growing use of DES for de novo lesions, we’ll need new studies to identify optimal therapy for ISR after DES implantation.

— Howard C. Herrmann, MD

Published in Journal Watch Cardiology May 11, 2006

Citation(s):

Stone GW et al. for the TAXUS V ISR Investigators. Paclitaxel-eluting stents vs vascular brachytherapy for in-stent restenosis within bare-metal stents: The TAXUS V ISR randomized trial. JAMA 2006 Mar 15; 295:1253-63.

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Holmes DR Jr et al. for the SISR Investigators. Sirolimus-eluting stents vs vascular brachytherapy for in-stent restenosis within bare-metal stents: The SISR randomized trial. JAMA 2006 Mar 15; 295:1264-73.

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Mukherjee D and Moliterno DJ. Brachytherapy for in-stent restenosis: A distant second choice to drug-eluting stent placement. JAMA 2006 Mar 15; 295:1307-9.

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• Medline abstract (Free)