A research group from University of California, Los Angeles has developed a novel material that can help fight peripheral arterial disease also known as hardening of arteries.
The condition is considered a red flag for vascular disease, heart attack and stroke, and its progression can result in the loss of limbs or death. While there are current treatments for PAD, including balloon angioplasty, stenting and bypass surgery, devices used in the latter two can frequently cause thrombosis, in which clots form inside blood vessels, obstructing blood flow and leading to serious complications.
The researchers are working on developing a PAD treatment device that can prevent thrombosis in small-diameter blood vessels.
They focused on stents that incorporate a material known as Nitinol, a superelastic nickel and titanium alloy that has the ability to be deformed and to recover its original shape upon heating.
"Nitinol, discovered back in the 1960s, is a shape-memory material. They thought it was going to revolutionize the engineering field. It wasn't until 1985 that people began to think this material would probably be great to use in a stent," said Greg Carman, a professor of mechanical and aerospace engineering and lead investigator for the multidisciplinary research team.
"The reason they liked it for a stent is because you could bend the material a very large distance and it would return back to its original shape.
"Other metals, such as surgical steel, do not allow such a large shape recovery and, as such, cannot be used in many stenting devices," Carman added.
In the early 2000s, Carman's group started looking into making thin-film Nitinol and accidentally stumbled across a way to fabricate what they believed was very high-quality, uniform-composition Nitinol.
"I immediately saw the promise that thin-film Nitinol had for intravascular and cardiac applications," said Dr. Daniel Levi, a pediatric cardiologist at Mattel Children's Hospital UCLA and a principal investigator on the team.
The researchers looked into producing stents that incorporated thin-film Nitinol on the exterior. Originally, the team considered it a possible treatment for neural vascular disease.
They then discovered that their thin-film Nitinol, at only 5 microns thick - compared to commercial stents, with a covering 100 microns thick - could be placed into much smaller tubes or catheters and used on much smaller-diameter blood vessels, like those found in limbs.
During testing, the team soon discovered their new stent possessed several attributes that could combat thrombosis.