In 2012, more than 3 million people had stents inserted in
their coronary arteries. These tiny mesh tubes prop open blood vessels healing
from procedures like a balloon angioplasty, which widens arteries blocked by
clots or plaque deposits. After about six months, most damaged arteries are
healed and stay open on their own. The stent, however, is there for a lifetime.
Most of the time, that’s not a problem, says Patrick Bowen,
a doctoral student studying materials science and engineering at Michigan
Technological University. The arterial wall heals in around the old stent with
no ill effect. But the longer a stent is in the body, the greater the risk of
late-stage side effects. For example, a permanent stent can cause intermittent
inflammation and clotting at the implant site.
In a small percentage of cases, the tiny metal segments that make up the
stent can break and end up poking the arterial wall.