Hi, my name is Dr Warrick Bishop and welcome to my podcast and videocast station. I really appreciate you tuning in and I really hope I can share something today that you find valuable and informative and interesting. Look, there's a couple of things I would like to define. today. The very first thing I'd like to define is this concept of family risk or family history of cardiovascular disease. Now, this is really, really important. I see plenty of patients who come in and they're worried because their cholesterol is up a little bit and they report that they've got a family history of coronary artery disease and that is concerning them because it might be putting them at increased risk. Well, When I ask these people a little more detail, I often find out that they're talking about Uncle Bulgaria, who is a distant uncle who may have had a heart attack or a stroke at 90 odd years of age. Well, off the bat, really importantly, having a heart attack or a stroke or some sort of cardiovascular event at an older age does not necessarily put the individual... who's concerned about their future risk at increased risk. When we talk about the family history that can put an individual at increased risk, we talk about a first-degree relative, so that is a parent or a sibling, or a child for that matter, a parent or a sibling who, as a male, has had a cardiac event at less than approximately 50 to 55 years of age without any other significant driving risk factor, or a female approximately 60 years of age, 55 to 60 years of age or less, who has not got any other driving risk factor, obvious one like smoking, for example, or marked obesity. So when we talk about family history or significant family history of coronary artery disease, which would put the individual that we're considering at risk, we are talking about males 55 years of age or less, females 60 years of age or less being affected, who are... first degree relatives of the individual whose risk we're assessing and there is no other striking feature. Now cholesterol can be raised and that can be included in that familial hypercholesterolemia discussion and can be included in that risk assessment. I'm talking about... risk factors that may impact that individual which are not genetic, such as lifestyle and social habits, alcohol, smoking, lack of exercise, significant obesity. So I hope that makes sense. First degree, so cardiovascular risk is significant for the individual we're assessing if they have a first degree relative who's had a cardiac event, a heart attack, Male, 55 years of age or less. Female, 60 years of age or less. This does not include rhythm problems necessarily or valve problems. We're talking about coronary artery issues only. I hope that makes some sense. The other thing I'd really like to define today is cholesterol. What is cholesterol? high cholesterol. Well, we know cholesterol is, well, needs to be broken down and thought about in different ways. And high and low is sort of meaningless without any context. First of all, when we think about cholesterol levels, let's think about high and low in terms of people who have had an event, secondary prevention, or not had an event, primary prevention. So for an individual who's had an event and we're looking to lower cholesterol to reduce future risk, a high cholesterol is an LDL cholesterol of over 1.4 millimoles per liter. These are the current world guidelines seen in the US, Europe, across Asia and in Australia. So 1.4 millimoles per liter if you have had... a previous coronary event, and above that would be considered high for you. If you are at super high risk, and there's some details that I could go into there, but people are at super high risk, getting that cholesterol level even lower becomes more and more important. So high cholesterol, if you've had an event, it's an LDL cholesterol, an LDL, cholesterol of over 1.4 millimoles per liter. Previously, our upper limit used to be 1.8 millimoles per liter, but in recent time that has been adjusted downward. Now, here's the complicated space around what's a high cholesterol in the primary prevention setting. Well, first of all, we see very high cholesterol. generally in association with a family history, and this is what we see in familial hypercholesterolemia. These individuals can have a total cholesterol over 7.8, a LDL cholesterol over 4.9. So these are very, very high. If you are thinking about individuals... height and comparing that to their cholesterol levels, these are the basketballers in the community, if you like. I'm not saying basketballers have raised cholesterol, but they are really right at the extreme of that bell-shaped distribution curve. So very high, total cholesterol over 7.8, LDL cholesterol over 4.9 millimoles per litre. High cholesterol is considered Total cholesterol 6.2 up to 7.7 and an LDL cholesterol of 4.1 up to 4.9. Now, I will mention that in the Australian guidelines, the recommendation is for people with the total cholesterol at 7.5 millimoles per liter or more, they should be offered cholesterol lowering therapy there and then as part of our guideline recommendations. Borderline high cholesterol, total cholesterol of 5.5 up to 6.2. And those borderline high people will have an LDL cholesterol of 3.4 up to 4.1. desirable would be a total cholesterol of less than 5.2 and an LDL of less than 3.4. And generally, we really hope to see an LDL cholesterol down as low as 2.6. I'll also add in there that when we look at the Australian primary prevention guidelines, they recommend an LDL cholesterol of 2.0. Now, when we're thinking about high cholesterol, it really doesn't make sense to think about it as pigeonholed and cutoffs, because, of course, this is a continuum. How could it be that, for example, up to 5.2, you're perfectly well, over 5.2, you go into high risk? Of course, that makes no sense. But these are guidelines. What's really important to understand is as that cholesterol level increases, we know the risk of plaque developing increases. As the risk of plaque developing increases, we know the risk of cardiovascular event increases. Remember, really important, we need to think about high cholesterol in this complex way where we think about people who've had an event, secondary prevention. People who have not yet had an event, and for those people who have not yet had an event, very high, often with a family history, as I've explained what a family history is, high, borderline high, desirable, preferred, and the Australian primary prevention target for LDL cholesterol of 2 millimoles per liter or less. Remember, though, it is a continuum, and we can see people with low cholesterols. that end up with plaque in their arteries. And we can see people with high cholesterols and no plaque in their arteries. Remember, once we get to very high in family history, these are the individuals we should be treating proactively to protect them in the future. One of the ways I often speak to my own patients about understanding the impact of this LDL cholesterol in the bloodstream is to use the analogy of parking your car by the sea. Now, if we take a brand new car and we park it by the sea, there'll be no rust if we walk around it. If we leave it six or 12 months, there's still maybe no rust. If we think about the salt air as LDL sea particles, then over time, there's a very, very good chance that the longer we leave that car parked by the sea, the greater the risk of rust, the further we move the car back from that sea air environment, that environment of rust formation, that environment of plaque formation, the slower the progression of rust, if you like, cholesterol buildup or atheroma within that car. And I think this is a really nice way to think about how that LDL-C cholesterol interplays. And we've got some really nice data that we've started to formulate, which talks about lifetime LDL-C exposure. Really, if you like, understanding that environment of plaque formation, a bit like we would understand an environment of rust formation if it were to be affecting our car. That helps a couple of definitions, family history, what's a high cholesterol, and some concepts around that environment of plaque formation. Well, I've been getting some questions from people who've been listening recently, and I really appreciate that. It lets me know that people are listening, and it gives me a chance to know what I can either clarify for you or what people have an interest in. So I'm happy to hear. I am open to any suggestions for future podcasts. And I think I've done a couple for people just recently. As always, I'm delighted if you have subscribed. I'm super delighted if you've subscribed and you've shared and recommended this to someone else. So please take a moment to do that if you wouldn't mind. It is my pleasure to share with you, actually. And I do hope you get some value from... these small snippets to help raise your medical literacy. For now, I am going to wish you the very best. I hope you live as well as possible for as long as possible. Take care and bye for now.
