The cutting edge: dissecting the heart
Surprising results ensure when dissecting the patient's heart as Chris Smith found out with Dr Alison Cluroe...
Alison - To take off the front of the ribcage and the breastbone we're going to need to use some shears... OK, so this is the inside aspect of this gentleman's breastbone, looking at it from behind as if we were standing inside his chest looking out, and what we can see here are these nodules on the surface.
Chris - So just to describe these a little bit. There are some little bumps; they're between a few millimetres and maybe up to a centimetre across; they're white and there are lots of them. It's almost like a rash, like a chickenpox rash but on the inside. What is that?
Alison - That's a tumour of some form. I'm not sure what tumour yet, I'd need to look at it down a microscope.
Chris - Do you think that the history of asbestos might be relevant?
Alison - It's possible, but this could also be a metastatic tumour from another malignant process. It doesn't have to be asbestos related.
Chris - Right. So, this is the heart?
Alison - This is the heart...
Chris - And it's very big...
Alison - It's a huge heart. Much bigger then if you were to buy a heart from the butchers shop. You often buy a beef heart or an ox heart. The heart is made up of four chambers; two ventricles - the big pumps, and two atrias - the sort of smaller pumps really. Now all the chambers of this heart dilated so this is a very big heart. It actually weighs 610 grams...
Chris - A normal would be half that, wouldn't it?
Alison - 300-350 for this sort of sized person. So I'm going to open up the heart now and we're going to have a look into chambers, particularly looking at the valves that help with the blood flow through the heart...
I've taken these cross-sections through the heart, like slicing an orange and looking at the segments. The most striking thing is the actual chambers of the heart are very large.
Chris - Why does that happen?
Alison - Because the arteries that supply the muscle of his heart may be narrowed and those blood vessels are just not able to supply as much blood as we would like to see. The other striking thing, that perhaps I should mention, is that although the ventricular chambers and the atrial chambers are quite dilated. The heart muscle is quite thickened and it's very, very marked on the right side here. That is at least a centimetre in thickness that right side, and that's much too thick for the right side.
Chris - Two or three times bigger than it should be, isn't it?
Alison - Two or three times bigger than it should be and likewise on the left even here, we're almost up to 2 cm in places. Now this is a big meaty heart and it's failed so it's become baggy and you can imagine that's not going to work as an effective pump to force blood around the body.
So what I've got left now having removed the heart are the neck structures and the arche of the aorta. Now the aorta, if you remember, is the great big artery that feeds blood around the body.
Chris - This is the big blood vessel, it comes off the top of the heart, it curves and does almost 180 degrees like a U turn, to then go down the body. That's what we've just opened up and the first bit of it looked OK, but this bit doesn't look so good.
Alison - And we've got these great big yellow hard plaques which have got calcium in them. So this confirms the fact that this gentleman does have quite significant atheroma (hardening of the arteries), and you can perhaps hear the calcium there...
Chris - There is, quite literally, a stone in the wall of the artery, and that's classic for someone having hardened arteries?
Alison - Exactly.
Chris - James - it really was striking how hard those arteries were. Why should arterial disease end up with calcium like that?
James - One of the ways that the body tries to heal this longstanding inflammation is by actually laying down calcium, exactly the same as would happen in a bone after a bone fracture.
Chris - So why should this healing process actually be bad news.
James - Most of the time the calcification of the arteries is a good thing. The body does succeed in stopping the inflammation happening within the arteries. Sometimes, unfortunately, it doesn't and the calcification itself can lead to problems such as heart attack and stroke. So the plaque within the artery ruptures, and that fatty gruel that's built up within the artery wall over many years is suddenly exposed to the blood flowing right past it and this can trigger immediate formation of a blood clot within the artery. And if this happens in an important artery like an artery supplying the brain with blood or the heart muscle with blood, then you get downstream reduction of blood flow to that organ and you get a heart attack or a stroke as a result.
Chris - James - the other thing we found was what Alison described as "a very baggy heart." It was extremely large. Why does it look like that and how does this relate to that diagnosis of heart failure?
James - This is because there's long term high blood pressure which has caused thickening of the heart muscle, as you would if you worked in the gym on your biceps. The muscle mass of the biceps would tend to increase and this has happened in this patient. But the other thing in this gentleman is that, as I said, the arteries are hardened so the blood supply to the heart muscle is reduced, and has probably been reduced over many years. And this causes the heart to experience what we call heart failure whereby the chambers of the heart actually get larger and, unfortunately, the pumping power of the heart, even though it's more musclebound, actually get lower, and lower, and lower as time goes by.
Chris - So despite being a bigger heart, initially that would have probably helped to overcome the fact that this guy had high blood pressure. Eventually, the chronic deprivation of oxygen and blood flow to the heart, and ongoing problems like hard arteries, means the heart just can't cope and it begins to become bigger.
James - Exactly. So initially the compensation that you've described, the heart becoming more musclebound, would certainly have worked for this gentleman but, unfortunately, the heart can start to fail and this is where we see the heart becoming extremely large.
Chris - And Prina - when we looked at the breastbone, there were lots of little tumours that we highlighted. We said possibly related to asbestos. Before we speculate what the lumps are, how does asbestos cause lung disease?
Prina - Asbestos was commonly used in building about 40 years ago. We don't use it so much now, it's banned...
Chris - It's a mineral, isn't it?
Prina - Yes.
Chris - You dig it up out of the ground.
Prina - Exactly. So it's a mineral with silica. It's just a very heat resistant, durable, and quite useful material because you can mix it with other things.
Chris - So does concrete and that doesn't give us cancer, so what's the difference the distinction?
Prina - It can become a dust which, once its inhaled, can migrate into the lungs and you can't break it down. So it just sits there and it can participate inflammation in the lungs.
Chris - So it's the fact that it's very small, gets very far into the lung that then doesn't get out again, that you get cycles of inflammatory damage?
Prina - Exactly. The body recognises it as a foreign body but can't break it down and so then that can drive mutations and form tumours.
Chris - And someone who has had a lifetime exposure of asbestos and might be developing one of these asbestos-linked diseases, what short of symptoms would they have?
Prina - There's a long lag time from asbestos exposure to developing an asbestos related condition.
Chris - How long?
Prina - For the cancers it's in the range of 20 years. For the fibrotic conditions it may longer, 40 years after the exposure. But symptoms may include breathlessness, chest pain, a cough. It can be quite vague symptoms and people may not realise for quite a long time before they present for medical attention.