|The Bioresorbable Vascular Scaffold is made of polylactide, which has been used in other dissolvable medical devices. Photo provided by Abbott Vascular.|
Whereas metal mesh coronary stents have been the more traditional path for angioplasty, with the option for drug-eluting devices, the Absorb Bioresorbable Vascular Scaffold (BVS) is intended to dissolve into the system within a year to allow the artery to return to normal functioning. Currently available in 35 countries, including those in Europe, Latin America, and Asia, Abbott is now starting a clinical trial with 2,250 patients who have coronary artery disease.
The scaffold is made of polylactide, a material that has been used in its technological predecessors, such as dissolvable sutures. The only exception is two pairs of tiny metal markers, which indicate to the physician where the device was placed. The product is also drug-eluting, delivering everolimus to the system as the artery recovers and the scaffolding breaks down. Abbott spent ten years trying to figure out the proper materials and engineering that would be needed for the device, which, although it is like a stent, it is not classified as one because it is intended to be temporary.
Steve Kelly, senior public affairs manager for Abbott Vasular, says that this technology is considered by the company to be the fourth revolution in the treatment in coronary artery disease, preceded by angioplasty, bare metal stents, and drug-eluting stents. “With no permanent metallic stent remaining, the vessel has the potential to return to a more natural state,” Kelly says. “It is free to move, flex, pulsate and dilate similar to a natural vessel in response to normal activities such as exercise.”
Although the company also produces both bare metal and drug-eluting stents, one of its long-term goals was to create a temporary artery scaffolding to potentially replace them. During the trial, Abbott will be putting the BVS against its own XIENCE, a drug-eluting metallic stent.
The BVS mirrors the multilink design found on Abbott’s metallic coronary stents, which provides similar flexibility to a normal stent. Unlike the metallic stent, the dissolvable nature of the BVS may produce fewer long-term complications, including late stent thrombosis, prolonged usage of anticlotting medications, and interference with medical diagnostic equipment such as MRI and CT scans.
The primary endpoint for the trial is target lesion failure, or a combination of safety and efficacy. Other endpoints, such as vasomotion, or a measure of how much natural motion returns to the vessel as the BVS dissolves into the arterial tissue, will also be examined in a handful of the patients. The company’s goal is to complete the trial to get the BVS in front of FDA for approval by 2015, and to make it available for the commercial market shortly after.