Bioresorbable Stents Promising But Metal Stents Still Have Role in Coronary Intervention
Absorb, the first everolimus-eluting bioresorbable vascular scaffold system, was approved for use in the United States in July 2016.
The FDA has approved the first everolimus-eluting bioresorbable vascular scaffold, Absorb (Abbott Vascular) for use in the United States.
The Cardiology Advisor recently spoke with physicians who said the stent is an important development, but unlikely to lead to major changes in clinical practice.
Last year, the European Union approved the use of Absorb, sold commercially as the Absorb GT1 Bioresorbable Vascular Scaffold (BVS) system. The pharmaceutical company stated that Absorb is the only fully dissolving stent approved for the treatment of coronary artery disease (CAD).
“This is a significant technological advance in that we now have a bioresorbable stent. But it's first generation,” said Manesh Patel, MD, director of Interventional Cardiology and Cardiac Catheterization Labs with the Duke University Health System. “It will have an effect, but I'm not sure it will have a huge effect yet because there are some limitations.
“We know that the strut thickness is a little bit larger and the stent is a little bit bulkier to deliver. Certainly we will be using it, but we'll be using it in larger vessels where we can clearly deliver the stent and clearly define where the stent is going to be placed after predilation.”
Absorb is designed to dissolve approximately 3 years after implantation.1 In results from the phase 3, multicenter ABSORB III trial, researchers found that 7.8% of patients randomly assigned to Absorb had target-lesion failure at 1 year compared with 6.1% of patients assigned to the drug-eluting stent, Xience (Abbott Vascular; 95% confidence interval: −0.5 to 3.9; P=.007 for noninferiority and P=.16 for superiority).
There were no significant differences between the Absorb and Xience groups in rates of cardiac death, target-vessel myocardial infarction, or ischemia-driven target-lesion revascularization. Device thrombosis within 1 year occurred in 1.5% of patients in the Absorb group and in 0.7% of patients in the Xience group (P=.13).
“At the end of the day, it's still a stent used to treat CAD. It's not going to change the way we treat that percutaneously in terms of coronary artery blockage,” said Shing-Chiu Wong, MD, an interventional cardiologist at Weill Cornell Medicine and New York-Presbyterian. “That said, it will change the clinical practice in terms of patient selection, the technique the stent requires. That's why I think the company, very wisely, is going to roll out that stent in a rather slow pace.”
Dr Wong worked with Absorb as part of ABSORB III trial. He said the dissolvable stent had clinical, philosophical, and cultural implications.
“In some cultures outside this country, [patients] don't want anything permanently inside the body. A lot of patients, if you give them a choice, would rather choose a stent that goes away after it does its job,” he said. “Once the stent platform goes away, the patient may have a more favorable clinical outcome down the road compared to a patient with an artery that will be caged by metal that will stay in place forever, but that will have to be demonstrated through further investigation.”
Both cardiologists foresee an ongoing role for metal stents, at least in the short term.
“It's going to depend on how well the next generation of bioresorbable stents replicate what the metal stents have been able to do with regards to deliverability and ability to keep the vessel open,” Dr Patel said. “In theory, if the technological advances with bioresorbable stents can deliver what the bare metal or even the drug-eluting stents can, then you would see the metallic stents disappear. But I would be hesitant to see them fully disappear until some advances have been made with bioresorbable stents.”
- Ellis SG, Kereiakes DJ, Metzger C, et al. Everolimus-eluting bioresorbable scaffolds for coronary artery disease. N Engl J Med. 2015;373:1905-1915. doi: 10.1056/NEJMoa1509038.