One of the commonest procedures performed around the world is called 'stenting'. It's
where doctors open up a blocked artery in the heart, and put in a little sliver of metal
to keep it open. But there have been allegations that far too many stents are being put in,
when medications and lifestyle change could do the job just as well, if not better. And
in fact, a cardiologist in the United States has recently been suspended for putting in
too many stents. So what is the story here? I spoke to a leading cardiologist, Associate
Professor David Playford.
Stenting in the setting of a heart attack is beyond question. So nobody would ever argue,
if somebody came in with symptoms consistent with a heart attack, about going straight
to the lab, getting pictures and fixing up the artery as quickly as physically possible.
In the setting of somebody who comes in with unstable symptoms or even symptoms that have
rapidly increased, again, opening the artery up quickly is beyond question. The question comes
in when somebody comes in with minimal symptoms, or symptoms that are not clearly due to angina.
And then looking for narrowed arteries, and if you find one, then opening that artery
up. There's no evidence whatsoever that that's beneficial. If anything, there is evidence
that that can cause harm.
And then there's this grey area called 'stable angina'. What is stable angina, and what's
the grey area?
Stable angina is reproducible symptoms with exercise.
Which creep up on you.
Right. It's due to the progressive narrowing of an artery that comes up over some time.
Plaque or cholesterol deposition in the artery that can slowly narrow it down to a point where
there's insufficient blood going through there at times of stress. Usually there are no symptoms
at rest because there is still enough flow down the artery for the metabolic demands
of the muscle. But with exercise, that fixed narrowing doesn't allow enough blood to go
down there to meet the demands of the muscle, and so that's when the symptoms occur; with
exercise. So a very important symptom with stable angina is that it's reproducible and
occurs every time with the same level of exercise.
And what you're talking about mostly is chest pain.
It's usually a discomfort, even the word 'pain' is not often used. It's often across the chest,
It may go up into the neck or the jaw or even the teeth or the gums, and it can sometimes
go down the left arm. It can be associated with other symptoms like nausea and a bit
of sweating, and often some breathlessness. But those symptoms are classical, and a lot
of people don't have classical symptoms. Any symptom that's reproducible with exercise
could be angina.
So why are so many cardiologists putting in stents for stable angina?
The key issue here is in relation to the underlying anatomy. If you've got stable or unstable
anatomy -- so if you come in with symptoms that are reproducible and the same every time,
or if you come in with symptoms that have suddenly occurred or or suddenly worsened,
or if you come in with a heart attack -- underlying there is still the same disease. It's
atherosclerosis. What atherosclerosis is, is a slow and progressive development of cholesterol
buildup within the wall of the artery, associated with inflammation. So inflammation is an essential
part of the process of development of atherosclerosis. The artery initially starts out with this
thing that we call a fatty streak, which is really just that that the artery's still the same size, there's
no narrowing of the size of the artery itself, the amount of blood going through is completely
normal. But eventually as this progresses through, you get the formation of actual plaque, which
is cholesterol deposits within the artery wall. It's almost like a semi-liquid
form associated with the inflammatory cells, and it's almost like a sore. It's hot, it's
inflamed and it's almost like it's got a scab on the top of it. And you still don't know you've got it.
So even though there may be a number of these throughout the body, there may be a number
in the coronary arteries, in the arteries that supply the brain, you don't know you've
got it. And the scary thing about atherosclerosis is that you may not have any knowledge that
there is a problem until the first complication, which could be a heart attack, or could be
a stroke.
And of course, the reason for talking about the underlying causes is that the stent is
more appropriate for one situation than the other. Yet cardiologists are putting in stents
for both.
Stenting is a very effective treatment for relieving angina. But what you're doing by
stenting is putting in a piece of metal. You're scaffolding this artery. And the scaffolding
itself is not an inert substance. It's like a bare metal barrier inside this coronary
artery. And the risk is that you could form a blood clot on there, or that the scaffold
can get covered over by tissue, and get ingrowth. Now in order to stop the ingrowth new stents
were developed which are called 'drug-coated stents'. They have this coating on the outside
of the stent to stop the tissue from growing back into it. The trouble with the drug-coated
stents is that they are so effective in stopping tissue growing into it that the tissue never
grew in, so there's this bare scaffold that was exposed to the blood. And so if you stopped
one of your medications to thin your blood, there is a significant risk of developing
sudden blockage of that stent, and a heart attack.
If you've got stable symptoms, if they've come on over a period of time and you've got
what we call stable angina, most of the time you don't need a stent. But if you come in
with sudden symptoms that have occurred at rest, most of the time you do need a stent.
Again, coming back to criticism of cardiologists, is that they treat the artery and not the
person. Because presumably, if you've got one artery which is diseased, you're going
to have far more than that in your body, and you'll never have enough stents to be able
to stent every artery that's sick in your body. What's the story in terms of holistic
care for somebody who's got one artery that's gone wrong?
Well, I think, the key thing is that you haven't just got one artery that's gone wrong. In
the situation of somebody who comes in with symptoms of some sort, it doesn't have to
be angina or a heart attack, it could be a stroke or a transient ischaemic attack, which
is like a mini-stroke, or some other abnormality. If there's any symptom related to the vascular
system, it means the problem is widespread, Atherosclerosis doesn't affect just that one
artery and leave the others clean. All arteries will be affected. So that means that whatever
the process is that's gone on to develop the narrowing over the lifetime of this individual, we have
to address everything in order to slow down the process. And if anything, we try to stop
the process getting any worse in the long term. What has been very clear is that an
improvement of weight, an improvement of diet, an improvement of exercise levels, do actually
make a difference in the long term.
As well as reducing your cholesterol and taking aspirin.
Even if you can get good lifestyle changes, there is very good evidence that long-term
therapy, once you've got atherosclerosis, you need the cholesterol lowering and you need the aspirin.