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BRITISH BROADCASTING CORPORATION
RADIO SCIENCE UNIT
CASE NOTES
Programme 3 - Coronary Artery Surgery
RADIO 4
TUESDAY 20/09/05 2100-2130
PRESENTER:
MARK PORTER
REPORTER: MOLLY BENTLEY
CONTRIBUTORS:
KEVIN BEATT
COLIN BAIGENT
BRENDA MOELLER
ANDREW MICHAELS
MARIO PETROU
PRODUCER:
PAULA MCGRATH
NOT CHECKED AS BROADCAST
PORTER
Hello. One in five British men, and one in six women, will die from coronary heart disease - furring up and blocking of the coronary arteries supplying the muscular heart wall.
Last year for a quarter of a million people, that progressive narrowing led to total blockage and heart attack - and for some much earlier than others. Half of all heart attacks occur in people between the ages of 40 and 75.
Death rates from coronary heart disease in the UK have plummeted in the last decade - partly through better prevention and awareness of the benefits of a healthy diet and lifestyle, and partly because of better medical treatment - but there is still room for improvement. Heart disease still exacts a bigger toll in the UK than it does in almost any other country in Western Europe.
In today's programme I will be looking at what we can do to further reduce that toll.
I'll be finding out if an aspirin a day really does keep the doctor away? Should otherwise healthy middle aged and elderly people routinely take low dose aspirin to protect their hearts?
And I'll be looking at a new approach to treating heart attacks - primary angioplasty - a technique that, according to doctors in the States, offers much better results than the clot-busting injections which are currently the gold standard here in the UK.
My guest today is cardiologist Kevin Beatt.
Kevin, why are the coronary arteries so prone to furring up?
BEATT
Well in many ways it's the result of our lifestyle, amongst other things, people who have high cholesterol levels, high blood pressure, increased salt intake, smoking, strong family history which predispose the individual to these risk factors.
PORTER
But presumably that process is going on elsewhere in the body as well, why are the coronary arteries so troubled by this?
BEATT
I think that it's not entirely understood why particularly some arteries are more prone to others. The coronary arteries are particularly susceptible but, for instance, the cerebral arteries will also be affected leading to strokes in the same at risk group of patients.
PORTER
And when you say at risk, you mentioned some of the risk factors there, these are all things presumably that accelerate the process of the furring up, the damage to the blood vessels?
BEATT
Yes they predispose - even patients without those risks can have furring of the arteries and develop heart attacks and patients in that category often feel very unjustly treated. But these particular factors increase the risk quite considerably and the risk is an exponential increase as you add on additional risk factors. So once you get two or three risks then you really are predisposed to having a ...
PORTER
So they're not adding to each other, they're literally multiplying.
BEATT
They're multiplying, exactly.
PORTER
And one of the areas of interest of yours is the role of diabetes, this is relatively recently understood isn't it, the effects of sugar and insulin on the lining of our blood vessels?
BEATT
Yes, it's surprising really that it's been so little recognised. There are a number of reasons why diabetes is becoming so important, both diabetes and pre-diabetic states. One is our general lifestyle and increase in weight, as the body mass index rises so does the risk of diabetes. But also particularly at risk are immigrant populations who are not used to - genetically used to living our type of lifestyle and they are particularly at risk of developing diabetes as they get older.
PORTER
Such as South Asians?
BEATT
Well yes South Asians in particular but there are many other groups. I mean in the United States the Mexican and South American populations are particularly at risk.
PORTER
What are the telltale symptoms of coronary artery disease - how might somebody know that they were developing a problem?
BEATT
Well I would always start with their overall risk. Many patients will not know that they have coronary artery disease up until the time they have a heart attack. But it is actually possible to predict patients who are developing coronary artery disease just by their risk score. For instance, if you have an individual with a strong family history of a heart attack in their family at a young age and they're a smoker, you can almost guarantee that they will be developing coronary disease.
PORTER
And at what sort of age might that become clinically evident in that sort of person - let's say a smoker with a strong family history?
BEATT
Right, well ...
PORTER
How young are we talking?
BEATT
Well 30s, in their 30s certainly. You will begin to see the change, if you look at the arteries, you'll begin to see the changes but most people in their 30s we don't look at their arteries.
PORTER
And of course the telltale symptom is - can be pain on exertion, so-called angina - what's going on there?
BEATT
Well angina is the classical symptom when the heart is starved of oxygen, so as - and it typically occurs when the individual exercises the heart, so as they try to do more the heart works harder, it can't get enough oxygen and the patients begin to experience a particular very unusual type of pain usually, which they've not normally experienced before, which is generally a tightening around the chest, rather than classical pain. And that's usually the first presentation.
PORTER
Well one of the reasons for falling death rates from coronary heart disease is the more widespread use of low dose aspirin in people thought to be at highest risk - such as those who have angina or who've had a previous heart attack - or indeed those at higher than average risk of heading that way, due to the risk factors we have already discussed like high cholesterol levels, diabetes, smoking and obesity.
Low dose aspirin - 75-150 mg a day, that's a quarter to a half of a normal aspirin pill - acts on platelets in the blood to make them less sticky, reducing the likelihood of the clot based blockages that lead to heart attack - and most types of stroke.
Colin Baigent is reader in clinical epidemiology at the University of Oxford.
BAIGENT
So we know from randomised trials that we can prevent heart attacks and strokes by giving low dose aspirin long term. We also know that in the acute situation where somebody's having a heart attack at that moment that giving aspirin can prevent people from dying from those disasters. So, for example, if we treated a thousand people with a history of heart disease or a history of stroke with aspirin then we might expect to prevent 10-20 heart attacks and strokes in each year that went by. In the acute situation we can stop heart attacks and stroke at that rate really in the first few weeks. So we've ended up in a situation where we recommend that aspirin is given immediately after a heart attack or stroke and then continued long term for at least a couple of years. And in fact most doctors carry on treating the patient long term.
PORTER
Given that stroke and heart attack are the two biggest killers of men and women here in the UK why doesn't everybody take a low dose aspirin?
BAIGENT
Well the problem comes when we start to think about the risks of aspirin because although aspirin is very good at preventing clotting it also, by that very property, tends to cause people to bleed. It also causes damage to the stomach and even in low doses can cause stomach ulcers. They then bleed and we end up in a situation where a patient may develop an ulcer that bleeds very substantially and that threatens their life. So we have to balance the benefits of aspirin against the risks of bleeding.
PORTER
There has to be some sort of threshold that we doctors work to before recommending aspirin. I know in the States, for instance, and you often read this in the papers, that they calculate the risk of stroke and heart attack generally across the population as being quite significant above the age of 50, is one of the risk factors they use, and it's not unusual for American doctors to recommend nearly everybody over the age of 50 take the low dose aspirin, could we see a similar sort of recommendation here in the UK?
BAIGENT
Well I would hope not. I think that if a person who hasn't got a history of heart disease or stroke thinks that it might be worthwhile for them to take aspirin they should go and talk to their doctor about it, that's the first thing. But we've looked at the data from all the trials that have studied people with no history of heart disease or stroke and what we've found is that actually the difference between the benefit in terms of prevention of heart attacks and the risk in terms of causing bleeding is very marginal. And there's a further problem - once we get into older people where certainly the risks of heart attack and stroke tend to increase, and so we might expect the benefits to be substantially larger, the problem is that the risks of bleeding are also substantially larger. So we've got to be very sure when we recommend aspirin's used widely, say above a certain age, that that's not going to cause net harm.
PORTER
Can we quantify that risk, if we look at the average middle aged man or woman who's not a particularly high risk of heart disease and they're self-medicating with low dose aspirin, what sort of risks do they face - we talked about the bleeds - but how likely is that?
BAIGENT
In middle aged people with say no history of dyspepsia - that's stomach upset - or peptic ulcer, they've actually found an ulcer in the stomach - in those types of people the risks are around about an extra one bleed for every thousand people treated for a year.
PORTER
A bleed that's serious enough to admit them to hospital and require a transfusion - life threatening bleed?
BAIGENT
A life threatening bleed or potentially life threatening bleed. Most bleeds, of course, are not fatal, only about 10% of bleeds are fatal. But still that's an appreciable quantity, we're talking about treating healthy people, we don't want to expose them to those risks.
PORTER
Have we got the threshold right, at what sort of level of risks should we be initiating aspirin?
BAIGENT
The key thing to remember is that everybody with a history of vascular disease - heart attack, stroke or even intermittent claudication, which is where the arteries of the legs are damaged. Everyone in that situation should be taking aspirin, unless they have a definite contraindication. And then we've got to start looking at obviously if we can prevent somebody from having a first event then that would be ideal. But as I say I think the evidence on which we base our recommendations has to be very, very much stronger than it is at the moment. My biggest worry is the older population in whom the risks of bleeding can get up to 1%, 2% per annum when you take aspirin and that seems to me to be a real problem if we start using aspirin widely.
PORTER
Colin Baigent.
Kevin, I suppose the key advice is that, people shouldn't be self-medicating with low dose aspirin unless they've been advised to by a GP or a cardiologist.
BEATT
Yes I think that's correct. It is not always easy to actually quantify the risk of people - the risk of developing problems from vascular disease and I think you do need advice as to whether you are one of those individuals at risk and need to take aspirin.
PORTER
And that advice can change from year to year as we learn more about who might benefit because I know there are trials ongoing at the moment.
Let's look at other ways of protecting yourself against coronary heart disease. Obviously lifestyle, you know smoking, keeping active, eating a sensible diet - I don't want to go down that route, most people should know that by now but it's important. But what about medicines, what can we do to reduce or slow down the furring up of our coronary artery?
BEATT
Well I suppose the classical medication that's most widely used are statins, that lower the cholesterol, and they've been found to be very effective at reducing events.
PORTER
And this cholesterol effectively is the waxy material that is actually causing the blocking is that right?
BEATT
That's right, that's right and importantly it's been shown to save lives and I think it is a very effective drug. The other thing that I always advise patients who are particularly at risk is fish oil - fish oil supplements - Omega 3 fatty acids.
PORTER
And that's through an effect on cholesterol as well or ...?
BEATT
The effect is not entirely understood but it - what is very clear is that in populations that have high intakes they develop very little coronary artery disease and I think that's always - that's more - to me that's a more powerful argument than most clinical trials.
PORTER
What about the impending signs of serious trouble - is there any way that you as a doctor can predict whether someone's just about to have a heart attack?
BEATT
No, I think there are patients who even when they're assessed in the normal way by exercise testing etc., can go out of your surgery and have a heart attack, so it can be very unpredictable. But I think I would first of all say what I would first look at is what is the overall risk, if the overall risk is high then you have to be very suspicious.
PORTER
Very wary of any symptoms they may have. And if they get - if the heart attack is the first sign, as it often is, particularly in younger people, it comes out of the blue, what can we do to prevent that damage, because that means the blood supply's now been cut off to part of the heart, we can use clot-busting drugs, will they return the blood supply to normal?
BEATT
Yes I think there is now the potential to completely return the blood supply to normal.
PORTER
If given how quickly?
BEATT
Well this is one of the important issues - it has to be given - clot-busting drugs work best when they're given really within the first hour. Unfortunately, very few patients, even doctors, when they have heart attacks, present within the first hour. So ideally this has led to a policy where we've tried to get thrombolytics moved out to ambulances etc., it's not been successful in this country for various reasons. And very few countries have actually been able to get early delivery of thrombolytics in the time that we would like.
PORTER
I want to stop you there Kevin because there is another approach to treating heart attack, we're going to talk about a little bit later. You can locate the narrowed area in the artery and you can stretch it back to normal size so blood can flow again - a procedure called primary angioplasty, and one that has now become routine in the States. Molly Bentley went to California to find out more.
BENTLEY
The Cath lab at the University of California, San Francisco Medical Centre, is open 24 hours a day every day of the year, short for Catherisation Laboratory. The Cath lab doctors, nurses and technicians are on call ready to receive heart attack patients. And on a Friday evening four years ago that patient was 62-year-old Brenda Moeller.
MOELLER
The pain came on, it started with the arm. Intense pain in my left arm. No pain in the chest whatsoever. I was sweating profusely, felt extremely weak, the ambulance driver told me it was an MI and I figured that was what it was, a myocardial infarction. It was scary.
BENTLEY
Dr Andrew Michaels, who's the co-director of the Cath lab, was on duty the night that Brenda Moeller was brought in.
MICHAELS
Time is critical. Every minute that goes by there's more heart muscle that's dying. Once a heart muscle cell dies it never comes back. So you're really on the clock to open that artery to the heart muscle as soon as possible.
BENTLEY
The quickest way to open up the artery, so that blood can flow through, is with coronary angioplasty. The procedure has been around for a quarter of a century but only in the last 10 years has it been used to treat artery blockage in an emergency, during a heart attack. First you have to find out where the blockage is. An angiogram let's you see right inside the blood vessels, by inserting a small tube through the leg - up into the aorta.
Dr. Michaels says that almost all patients - regardless of age - are candidates for angioplasty. It's minimally intrusive - there are no open incisions - and a tiny balloon is used to get the blood flowing through the vessel again.
MICHAELS
Well the balloon is amazingly small, it comes tightly wrapped around a very small catheter, so you advance this catheter, you slide it over the guide wire, you reach the area of blockage, and then when you inflate the balloon that pushes the cholesterol plaque and the blood clot out of the way, then you deflate the balloon and remove the balloon, and then the blood flow is re-established.
BENTLEY
Brenda Moeller's right artery was 95% blocked when she was admitted. But Dr. Michaels had to take a less usual route to her heart. Brenda Moeller says she only remembers being in the Cath lab and feeling a slight prick in her groin - and then resistance.
MOELLER
The prick that I felt was them trying to go in through the groin, through the artery in the groin, but it was totally blocked. And they decided to go in through the wrist, that was the only other way to do it, otherwise they wouldn't have been able to get in there. So that's what they did, they went in through the wrist with the angioplasty and then followed by the stent in the right artery of the heart.
MICHAELS
And a stent is a small metal tube that comes crimped on one of these balloon catheters, and you position the stent across the blockage. When you inflate the balloon, the stent expands and becomes compressed against the blood clot and cholesterol plaque, and having that stent scaffolding there will help prevent a re-narrowing of that vessel over time.
SOUND OF CATH LAB
BENTLEY
This stent stays permanently in the heart. Back at the Cath lab, Dr. Michaels follows up on a patient who received three stents five years ago - to see how they were holding up, and whether he needed another.
ACTUALITY - LAB
If something feels sharp in your leg just let us know. We're all done with the pictures, all three of your stents look perfect.
BENTLEY
Blood-thinning drugs are delivered during the balloon and stent procedure to prevent a clot from developing on the stent or guide wire. The results are more successful than the old-style clot-busting or thrombolytic drug.
MICHAELS
When you give a thrombolytic drug intravenously only about 60% of those arteries are going to re-establish with normal blood flow. When you open it with a balloon or a stent you're up at around 90, 95% chance of getting that artery open with normal flow, and not only immediate, there is some long-term benefits of balloon angioplasty and stenting. It's a much more durable result - particularly with drug-eluting stents, there is less than a 5% chance that artery is going to close up again.
BENTLEY
That's good news for patients like Brenda, who has a positive outlook on life.
MOELLER
Prognosis as far as I can understand, of course I am a terrific optimist, is I'm going to be fine, as long as I take my medication and watch my cholesterol.
BENTLEY
Did they talk about the chances of re-blockage when you have a stent?
MOELLER
Well Dr. Michaels told me that with this stent, if it didn't re-block, or start to re-block, within a three month period, it probably would not.
BENTLEY
And how much time has gone by since he said that?
MOELLER
Four years! So I'm quite encouraged that it's not going to re-block. I do have other arteries though on the heart that are 50% blocked, as he's explained it to me, so I have to make sure that I don't let those get going any further.
PORTER
Molly Bentley talking to Brenda Moeller in California. You're listening to Case Notes, I'm Dr Mark Porter and I am discussing coronary heart disease with my guest cardiologist Kevin Beatt.
Kevin, do we do treat heart attacks in the same way here?
BEATT
Well there are a few centres in the UK that are offering this treatment, even fewer that offer it around the clock. In the west of London we've offered this service for the past three years and it's probably the most advanced programme I think in the country.
PORTER
I mean it sounds a fantastic way, I mean presumably you agree with those sorts of success rates, I mean they're much more successful than using the thrombolytic drugs.
BEATT
Yes, our data shows that we reduce mortality by 80%, which is in the scheme of things a very big reduction.
PORTER
Which is great if there's a 24-hour centre near you and as you said there aren't in most parts of the country and if there doesn't happen to be a patient in there already before you having the procedure done. It's only going to be for the lucky few isn't it?
BEATT
Well I don't - I don't really think so. Of course we do have to change the way we work and the question is should cardiologists group together and provide this service or should we just carry on in our disparate centres as we have done in the past? My view is that we can - we've shown that we can do it and it is the correct thing to do and I'm sure that we will eventually move that way nationally.
PORTER
In the meantime angioplasty is very widely spread - widely used now to prevent problems isn't it, I mean you're actually going in with people who've got angina to prevent a heart attack.
BEATT
Yes I think they referred to the use of drug eluting stents in the previous interview there and that has really revolutionised the treatment of angioplasty.
PORTER
And they are?
BEATT
Well these are the stents that are crimped on to balloons, the difference with the drug eluting stents is that they have a special coating on them that prevents scarring. The problems with what we call the bare metal stents, the original stents, is that they did have a tendency to block off again in about 20-30% of patients and we've now reduced that to probably under 4% now.
PORTER
Well angioplasty is an ongoing exciting development but some patients still need the more conventional, and more invasive approach of bypassing diseased coronary arteries with healthy vessels stripped from elsewhere in the body - coronary artery bypass surgery. Mario Petrou is a cardiac surgeon at the Brompton in London and performs hundreds of bypasses every year. We caught up with him as he prepared to operate on a 69 year old gentleman with angina.
PETROU
For most cases it's a mid-line incision in the middle of the front of the chest but also there are more peripheral incisions, like in the leg or the forearm because that's where we harvest the veins and the spare arteries to perform the bypasses with. For the conventional operation when we stop the heart and we use the heart/lung machine I'll say to the patient that there will be a period during the operation of approximately an hour when their circulation will be supported by a heart/lung machine. And that will enable us to do the delicate sewing of the grafts on the still heart.
So the first thing is to make sure that the quality of the conduits, as we call them, are very good, there is no point putting a tatty piece of vein, as it were, on the heart, the patient deserves better but also it will translate into a better clinical outcome.
What's your ACT?
[Two hundred]
Thank you very much. And now the next step really is to connect the patient's circulation to the heart/lung machine and these pipes we have here enable us to do that. Okay if everyone's happy can we go on bypass please. And there we are the pipes are filled with the patient's own blood that's circulating. And that enables the heart to do significantly less work, it's now much smaller than it was before, it's decompressed. And in a moment we'll switch the lungs off as well because the heart/lung machine will both oxygenate the blood and pump it around the body.
The word bypass is actually very appropriate and very apt because that's exactly what we're doing. We start off with the image provided by the angiogram - that's the investigation the patient has that's performed by the cardiology team - and that provides me with a roadmap basically and tells me where the narrowings are in the arteries. And the aim of the operation is to use spare veins and arteries to literally bypass around those narrowings. So the narrowings and patient's intrinsic arteries of the heart remain, we don't remove those. They stay as they are and we place the additional bypass vessels around those narrowings, so that the blood can flow into the heart uninterruptedly.
What I'm doing now I'm gently picking up the heart and examining the coronary arteries and what I'm doing I'm correlating the roadmap that I've seen on the angiogram with what's actually happening on the heart itself. And that will enable me to choose just the right targets on to which to graft. So I think we're going to do three bypasses here - a triple bypass.
The more severe extensive coronary artery disease patients are the ones we tend to see now because quite often that pattern of coronary disease is not really amenable to the stenting procedures that are usually very successful. That situation is still evolving however and it may be that in five years time all-comers with coronary artery disease will indeed be treated by cardiologists. I personally have my doubts about that, there will still, I believe, remain a proportion of patients with quite nasty, quite extensive complex coronary disease that I believe can only really be treated effectively and safely with surgery.
PORTER
Heart surgeon Mario Petrou - and I pleased to say the patient is recovering well.
Kevin, what determines whether someone with angina ends up being treated by a surgeon in that way or in a less invasive way by somebody like you?
BEATT
Well I think this varies around the country, it varies between hospital and between operator. Conventionally surgeons have done the more difficult cases and people like myself have done the relatively easy cases. What we're now finding because of the operative risk of the more risky patients is that we're increasingly taking on more difficult cases, so that we find the very high risk patients are in fact now having angioplasties rather than surgery.
PORTER
Because you're less invasive and it's less likely that you'll do - I mean basically they've got more chance of surviving the procedure.
BEATT
Yes I think it comes down to the co-morbidity, so these are the non-cardiac complications, things like renal failure and stroke, which are appreciable in some patients who are offered cardiac surgery, particularly the elderly.
PORTER
That's all we have time for. Dr Kevin Beatt, thank you very much.
As always you can access useful contacts and addresses on coronary artery disease via the Radio 4 Action Line that's 0800 044 044 or through our website at bbc.co.uk/radio4 where you can also listen to any part of the programme again.
We are out and about for next week's programme, for a behind the scene look at the world of the anaesthetist - if you have ever wondered what goes on after you've gone under then join me to find out.
ENDS
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