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Early Results with Biodegradable Stents

The proven benefits of current metallic intracoronary stents -- namely, sealing intimal dissections and preventing restenosis -- are realized during the first 6 months after implantation. Therefore, stents that biodegrade after 6 months may offer the same benefits without the potential risk for long-term complications. This report from the Japanese inventors of a poly-l-lactic acid (PLLA) stent describes the first implantations of biodegradable devices in humans. The stent is a self-expanding coil made of PLLA monofilament in a zigzag helical design; it is deployed using a balloon inflated with heated dye.

A total of 25 stents were implanted for 19 lesions in 15 patients. All stents were delivered successfully, which resulted in a decrease in percent diameter stenosis from 64 percent to 12 percent. One day after stenting, there was no evidence of additional recoil according to either angiographic or intravascular ultrasound (IVUS) measurements; within 6 months, there were no stent thromboses or adverse cardiac events. The 6-month binary angiographic restenosis rate was 10.5 percent. IVUS analysis demonstrated further stent expansion between 1 day and 3 months, with stent struts still visible at 6 months.

Comment: This is the first study to demonstrate the feasibility and safety of implanting coronary biodegradable polymer stents in humans. As the editorialists note, because there have not been any reported problems with metallic stents even after 6 months, the greatest promise for biodegradable stents may lie in their ability to serve as vehicles for local drug delivery. Longer follow-up is essential, however, to determine whether problems develop as stent dissolution occurs.

— HC Herrmann

Published in Journal Watch Cardiology September 29, 2000

Citation(s):

Tamai H et al. Initial and 6-month results of biodegradable poly-l-lactic acid coronary stents in humans. Circulation 2000 Jul 25 102 399-404.

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Colombo A and Karvouni E. Biodegradable stents: "Fulfilling the mission and stepping away". Circulation 2000 Jul 25 102 371-373.

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• Medline abstract (Free)