Highly anticipated research on Abbott Vascular’s bioresorbable coronary stent was revealed over the weekend, and results were a bit underwhelming for cardiologists who hoped it would outperform metallic stents.
Two studies comparing the Absorb BVS to Abbott’s metallic stent Xience V were presented at this year’s TCT Conference in Washington, D.C. Bioresorbable stents offer major benefits including they fully dissolve over approximately three years, restore vasomotor function and pulsatility, and allow the heart to function more naturally than it would with a metallic stent, which remains in the body permanently.
Despite these benefits, they’re also more expensive, and results of the study didn’t show that it worked much better than the Xience model.
A study conducted by interventional cardiologist Runlin Gao, MD, included 480 patients from 24 sites in China. Results showed that after two years, rates of clinical events, cardiac death and device thrombosis occurring in patients with Absorb BVS were comparable to those with Xience.
In a separate study comparing the stents, led by Patrick W. Serruys, MD, PhD, researchers looked at three-year outcomes in more than 500 participants from 46 sites throughout Europe and New Zealand. The team found a significant difference in the stable mean lumen area in patients with Absorb BVS. They found that patients with Absorb BVS had less lumen area.
Much of the reason Absorb BVS didn’t outperform Xience in the trials can be attributed to physicians not implanting Absorb stents properly, said Charles Simonton, MD, chief medical officer at Abbott, in an interview with Cardiovascular Business.
“What we learned in two or three years is that the key to really good outcomes with Absorb is getting a really good final expansion of the scaffold or the stent itself,” Simonton said. “The patients in the trial were enrolled about two years before we actually discovered how to properly implant Absorb. So we weren’t surprised that the results were not up to par.”
Simonton said physicians weren’t sure how much pressure they could use on the Absorb stent while implanting it because of its polymeric plastic form. Throughout the trials, they have developed new techniques and are now using them when placing stents into patients. Data from those more recent patients has yet to be published.
“The results now, what they reflect, is what you can get if you implant the device the way we did it back then, which is not the way we’re doing it now,” Simonton said. “Next year you’ll see some of the other Absorb data coming out and that hopefully will help clarify some of this.”