Advances in bioresorbable stents show promise for treating PAD

Bioresorbable stents initially gained attention a decade ago as a potential revolution in coronary interventions and there was a lot of hope the U.S. Food and Drug Administration (FDA)-cleared Abbott Absorb. However, challenges related to strut thickness, vessel opposition, poor performance in small vessels and scaffold durability led to setbacks, which led to the Absorb being pulled off the market. Despite this hurdle, there were many valuable lessons learned that are now being used to build better scaffolds now in trials that have revitalized interest in these stents, particularly for peripheral applications.

A new wave of bioresorbable stents

Today, bioresorbable scaffolds are seeing renewed momentum, with a focus on below-the-knee interventions. The Abbott Esprit stent, which builds upon the previous Absorb bioresorbable technology, has received FDA clearance and demonstrated strong clinical trial performance. Secemsky told Cardiovascular Business its improved design, featuring a smaller strut thickness, has made it a viable option for PAD patients.

He said other companies are now entering the market with promising innovations. Reva Medical recently completed the MOTIV trial for its Tyrocore-based bioresorbable scaffold. The new plastic material enables much smaller stent strut than traditional polylactic acid (PLLA) used on the Absorb, down to about 95 microns. Secemsky said the Tyrocore platform is also designed to improve visibility on angiography and performance.

Meanwhile, R3 Vascular has developed a PLLA scaffold with high molecular weight, thinner struts, and strong radial strength.

Beyond polymer-based scaffolds, Biotronik is developing a bioresorbable magnesium stent, which is currently in the planning stages for a U.S. clinical trial. These stents offer an alternative to traditional PLLA models, potentially broadening treatment options for patients with PAD. This stent begins to dissolve after impact and loses about 40% of its mass within the first 90 days, and about 95% of its mass by one year. PLLA and Tyrocore scaffolds dissolve over the course of about three to four years, and uncage the vessel to allow normal vasodilation after about nine to 12 months.

"It will be nice to have some options here and look at the different properties, strengths and weaknesses of each of the technologies," he explained.

Secemsky emphasized the importance of vessel preparation and imaging to ensure the success of bioresorbable stents, which do have limitations and handle differently that metallic stents. He said intravascular imaging and possibly cardiac CT angiography could play a role in improving reservable stent outcomes.

Looking ahead to coronary applications for absorbable scaffolds

While current efforts focus on below-the-knee interventions, there is growing interest in expanding bioresorbable stent applications to above-the-knee PAD treatments, and even reintroducing them into coronary artery disease management. However, Secemsky said the emergence of drug-coated balloons in coronary interventions has introduced new competition, raising questions about how bioresorbable technology will fit within the broader interventional toolkit.

Despite past challenges, the latest generation of bioresorbable stents demonstrates significant progress in structural integrity, durability, and clinical efficacy. As new trials continue to unfold, these advancements could mark a new era in vascular intervention, providing patients with safer and more effective treatment options.