The quickening pulse of medical device design, not to mention the pace of investment by leading manufacturers, points to bioabsorbable polymers as a big part of the future roadmap for coronary stents.
New drug-eluting and bioabsorbable stent designs using polymer materials have the potential to improve patient outcomes while allowing the native blood vessel to heal naturally. Unlike metal stents, the biodegradable materials dissolve and can be completely absorbed by the body over time.
Regulatory approvals and the investment required to bring a new stent to market propel substantial design innovations that result in improved patient outcomes—and challenge manufacturers to identify how to cost-effectively machine these new biodegradable polymer materials and micro-features.
Femtosecond lasers are already emerging as the enabling technology to commercialize complex, next generation stent designs with more intricate patterns and shrinking stent sizes which enable deeper access to smaller spaces in the cardiovascular system.
Bare Metals to Polymers
Little more than twenty years ago, the introduction of vascular stents transformed the treatment for coronary atherosclerosis disease and immediately improved patient outcomes. Turning angioplasty procedures into minimally invasive techniques, the use of coronary stents keeps arteries and blood vessels open around the heart.
The first generation of both coronary and peripheral stents was designed from bare metals, like 316L stainless steel, and dramatically reduced the risks of restenosis (narrowing of the blood vessel) or thrombosis (blood clots) when compared with earlier medical interventions.
Bare metal stents (BMS) material continues to evolve with the introduction of better-performing gold, platinum, nitinol, cobalt chromium and memory shape alloys to improve device delivery, flexibility and residual strength.
Medical device manufacturers quickly turned from mechanical tooling and fabrication methods to laser micromachining of bare metals in order to reduce the thermal effects and melt areas, recast or burrs which require costly acid etching, bead blasting and interior dimension honing re-work to correct.
But even longer-pulse lasers diffuse heat and heat affected zone (HAZ) damage to stents, limiting design and features while creating time-consuming, post-processing steps to meet quality control.
As the market shifts from bare metals to polymer stents, today’s longer pulse continuous wave (CW), nanosecond and picoseconds lasers are not capable of processing the heat-sensitive, biodegradable polymers.
Drug-eluting stents (DES) promise to deliver drugs more effectively to the target treatment area over a longer period of time, improving vessel wall healing and further reducing the risks of inflammation. The three DES components are the bare metal scaffold, the drug and the biodegradable polymer coating that carries the drug.
Polymer bioresorbable vascular stents (BVS), including poly-L-lactic acid (PLLA) and poly lactide-co-glycolic acid (PLGA), elute 100% of the drug as prescribed before the stent is completely absorbed by the body within a matter of months. The polymers will dissolve to nontoxic byproducts and disappear, enabling the body and arteries to return to a more natural healing process.
All-Laser Solutions Enable Innovations Roadmap
Biodegradable polymer stent materials require system flexibility, precise energy and an ultrashort femtosecond laser pulse width – in the one quadrillionth of a second regime– to achieve true athermal laser processing. This eliminates heat transfer or damage during manufacture as well as any risks to device integrity or performance with one-step, non-contact processing that delivers superior part-to-part consistency.
Raydiance’s all-laser precision manufacturing solutions enable rapid prototyping and ROI with seamless transition of new parts from design to production. This makes validation of production processes relative to regulatory requirements straightforward and predictable—also enabling the future innovations roadmap for medical device applications.