There’s a battle underway among bioresorbable stents – polymer vs. metal. Which is the best option for clinicians and patients?
Bioresorable (also known as bioabsorbable) stents are being held up as a promising alternative to standard drug eluting stents. But there’s an internal battle (no pun intended) going on with bioresorable stents as well. Are polymer-based bioresorbable stents ideal for patients? Or should doctors opt for their metal counterparts?
Cases were made for both at the 25th annual TCT Conference in San Francisco, but researchers agree that polymer platforms have more data behind them. However, metal platforms should not be discounted as they may offer significant advantages over polymers.
The Case for Polymers
Right now polymer-based scaffolds (which are made of PLLA) have simply outpaced metallic bioresorbable stents when it comes to the quantity of data available. Dr. Syed Hossainy, director of the innovation incubator at Abbott Laboratories, a division of Abbott Vascular, said, “The reason I’m on the side of favoring polymer-based scaffolds is derived from significantly more clinical data that’s available. Some of it is in comparison with the leading drug eluting stent [DES] and second generation DES designs. Lastly, there is a significantly more understanding of the mechanistic function for PLLA-based platform as opposed to a metallic absorbable scaffold.”
Indeed Abbott has collected nearly five years of clinical trial data between two different designs for its Absorb bioresorbable scaffold. The Absorb Cohort B study (conducted by Abbott), demonstrated that the Absorb scaffold has a comparable clinical performance to XIENCE, the current standard for non-absorbable drug eluting stents.
Another study conducted to compare the Absorb to the Absorbable Metallic Stent (AMS) which made of magnesium and manufactured by Biotronik, found that the quick absorption of magnesium likely caused less structural integrity as compared to the Absorb, and that PLLA, unlike magnesium, does not immediately lose load bearing ability as it breaks down.
As the magnesium scaffold breaks down it was also found to leave chemical byproducts that could lead to potential complications such as ectopic calcification (calcium deposits in the soft tissue), whereas PLLA naturally breaks down into water and carbon dioxide, which are both naturally absorbed by the body.
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Source: www.mddionline.com; Chris Wiltz; October 31, 2013.