Bioabsorbable Polymer DES Represent Evolution to Stenting Platform

Few early differences exist among the various iterations of drug-eluting stents (DES). Instead, disparities between bioresorbable and permanent polymer devices only emerge over the long term, according to a lecture focusing on the future of metallic DES held Monday at TCT 2014.

Juan F. Granada, MD, Executive Director and Chief Innovation Officer of the CRF Skirball Center for Innovation, Orangeburg, N.Y., discussed the technological and therapeutic nuances of durable vs. bioabsorbable polymer DES.

“In the early phases of healing and due to the presence of polymeric carriers and antiproliferative drugs, minimal differences in device thrombogenicity may be seen between different DES technologies,” Granada explained. “Beyond this early phase, stent surface biocompatibility and thrombogenicity plays an important role in long-term clinical outcomes.”

Although permanent polymer DES provide low rates of restenosis and stent thrombosis, he said, there remains room for improvement in clinical outcomes. For example, high-risk patients with complex lesions tend to have more aggressive thrombogenic milieu, therefore ancillary devices and overlapping stents are used. Rates of stent thrombosis in this subset remain high, and prolonged dual antiplatelet therapy should be maintained to ensure safety.

“In the experimental setting, abluminally placed bioabsorbable polymers display lower degrees of vessel wall inflammation and thrombogenicity when compared with durable polymers,” he said. “However, large randomized controlled clinical trials may be required to prove the clinical superiority of this technological approach.”

Depending upon the polymer-drug absorption time, Granada said the net effect on healing may be comparable between bioabsorbable and durable polymers within the first 6 to 9 months. Once the drug is out of the stent and the polymer is in the process of degrading, there are differences in healing times between metallic and polymeric surfaces. Migration speed of endothelial cells is more than twofold with grooved surfaces vs. flat metal surfaces.

“It is very difficult to group all of the concepts of every single bioresorbable DES either under development or in the clinical arena,” he said. “One of the reasons is because every technology has a different stent platform, different drug or polymer type, and all of these differences contribute to the overall efficacy of the vessel.”

Disclosures:

• Granada reports research/grant support from multiple pharmaceutical and device companies and receiving consultant fees/honoraria from Boston Scientific and Covidien.