Doctors Excited by 'Breakthrough' Heart Stent
WebMD News Archive
"I'm impressed," said Dr. Karl Karsch, head of
cardiology at Bristol University in England, "but I'm always suspicious
when the complication rate is zero. We have seen devices before that were very
promising at this stage. Everybody was excited and it turned out that after two
or three years there was a certain [relapse]."
Van der Giessen added that the rarely reported problem of
contaminated (or infected) stents may get worse because the drug coating
hampers the immune response.
More than one third of heart disease patients get angioplasty
-- about 1 million people every year worldwide. Some patients have it done
several times because their arteries keep renarrowing. An additional 700,000
people worldwide have heart surgery every year.
"At the moment, many patients are still treated with
medicines, unless they have a [significant artery] blockage. Now, if you have a
safe device that really works -- the effectiveness of angioplasty is now over
90% -- [fewer] patients will go to surgery," Morice said.
With simple angioplasty, a balloon at the end of a long tube is
threaded through an artery in the groin. The doctor shimmies the probe up
through the patient's leg and right into the arteries of the heart, inflating
the tiny balloon at the spot where the vessel has narrowed. The balloon cracks
open the plaque and stretches the walls of the vessel. Then the balloon is
deflated and removed. In about 25% or 30% of patients, the arteries close up
To keep the vessel open, doctors often add a stent to the end
of the balloon catheter. Stents bring the rate of renarrowing down to about 15%
to 25% of cases.
It happens because the blood vessel wall is injured when the
stent is implanted. The area then becomes inflamed and new cells start to grow
to form scar tissue. The attempt to heal the wound becomes exaggerated and the
artery walls become so thick that it sometimes protrudes into the inside of the
mesh scaffold. This tends to happen within six months of the stent being