Welcome, my name is Dr. Warrick Bishop. I'm a cardiologist, an author and a keynote speaker. I'm CEO of the Healthy Heart Network. I'm all about trying to help people live as well as possible for as long as possible. Heart disease is huge in Australia. Every 20 minutes someone suffers a heart attack. Most of these could probably have been avoided if only we knew what to do. This podcast is all about helping you understand blood pressure, weight, cholesterol for better health. If you enjoy this podcast, I would be honoured for a five-star review. You can share it with your family and friends. It may well save someone you love. Hi, my name is Dr. Warrick Bishop and today I'd like to talk a little bit about blood thinners. Well, you'd probably be aware that there are blood thinners that we use to keep the platelets. Less sticky platelets are non-cellular particles that float around in the bloodstream and help with clot formation. They have lots of receptors on them and they're always looking for damage to the lining of the blood vessel so that they can clump and prevent us bleeding to death. So we have anti-platelet agents. Then we have anticoagulants. Now warfarin is the one that's been around forever and warfarin blocks the production within the liver of a number of the vitamin K dependent clotting factors. That's 2, 7, 9 and 10. We also have another group of anticoagulants and then the non-vitamin K oral anticoagulants or NOACs. needs these medications and when do they need these medications? Well, the antiplatelet agents, aspirin and the other agents, such as clopidogrel, which you may have heard of, such as prezogrel, which you may have heard of, these agents are... critical in the management of atherosclerosis because they reduce the chance of clot forming within an artery. So atherosclerosis is evidenced by ischemic heart disease, stroke or peripheral vascular disease. These patients will, by default of their condition, require some sort of antiplatelet therapy. In the setting of cardiac disease, specifically if an individual needs a stent, we know that to try and keep the blood thin while that stent is covered by the internal lining of the blood vessel, those individuals will need two antiplatelet agents for a period of time. It can be up to a year, it can vary, but we use a dual antiplatelet therapy regime when a stent is implanted. It's very, very important to be in touch with the cardiologist, the interventionalist who put that stent in because the nuances of that implantation may determine the recommendation for dual antiplatelet therapy. For example, bifurcation stents are complicated and the... Interventionists may recommend antiplatelet therapy for an extended period of time subject to review. Sometimes a stent inside a stent may define that this person is at higher risk and therefore may require dual antiplatelet therapy for a longer period of time. This individual may also be someone who suffers from atrial fibrillation and therefore be on an anticoagulant, in which case there would be a balance of dual antiplatelet therapy run at what would be considered a minimal time to give that person maximal safety without the risk of two antiplatelet agents and an anticoagulant giving rise to problems with bleeding. So it's very important. that the message about anti-platelet therapy post-stent is guided by the interventionalist who will have the best idea of the risk inherent for that particular individual and that particular procedure. Well, let's move on to the anticoagulants. Well, warfarin's pretty old and it is something that does take a bit of work to prescribe and live with because of regular blood tests. So why would we still use it? Well it turns out that in certain situations warfarin just outperforms the non-vitamin K oral anticoagulants. So the new agents just don't match warfarin in two very important situations. The first is in rheumatic heart disease mitral stenosis with atrial fibrillation. So where there's narrowing of that mitral valve and associated atrial fibrillation, our research still tells us that the warfarin anticoagulation regime is more effective than the NOAC anticoagulation regime. This is one of the reasons that when an individual is diagnosed with atrial fibrillation and a regularly irregular pulse, it's very important that that individual see the local cardiology service so that at least an echo of the heart can be undertaken to discern whether that individual is non-valvular or valvular mitral stenosis atrial fibrillation because that will define the best care for that individual. So mitral stenosis atrial fibrillation is managed with warfarin, not a NOAC. The other situation where we believe warfarin offers benefit over the NOACs is in mechanical valves. Now, for some reason, it seems that the propensity to form clot on these valves is not covered as well by the non... vitamin K, oral anticoagulants. We don't really know why, but for now, all our research has told us that warfarin is the agent of choice, and it's very important that this is adhered to and understood. This will be guided very much generally by the cardiologist for the individual who has a mechanical valve. So where do we use the NOACs, the non-votum K oral anticoagulants, well in non-valvular atrial fibrillation they really have proven to be at least as effective as warfarin, perhaps a little bit more effective with less side effects and much more convenience. So they are truly the go-to for non-valvular atrial fibrillation. They work really well, they're very well tolerated and they really do the job. We also know that these non-vitamin K oral anticoagulants are beneficial for the management of pulmonary embolus. They work very quickly at the time of diagnosis of pulmonary embolus or even DVT. These agents can be implemented. Their serum levels rise very quickly and therapy at a known level can be undertaken effectively and efficiently for that individual. So we've talked about thinning the blood either through making the platelets less sticky or by altering the coagulation cascade by dampening down or obstructing the function of some of the compounds, some of the particular proteins within the coagulation cascade. What about stopping some of these medications? When might we do that? Perhaps if someone needed surgery. And this becomes really very important and it's something I'd like to talk about and emphasise a little. When it comes to stopping dual antiplatelet therapy, as I alluded to, this really needs to be guided by the individual who... put the stent in or by the cardiologist who's responsible for that patient. There are nuances and specifics around individuals that may mean this person should be on dual antiplatelet therapy longer than the average or less than the average. So I would defer in that situation to the cardiologist who knows that patient best and generally that will be the interventionalist who put the stent in. Well, what about warfarin and novel oral anticoagulants or non-vitamin K oral anticoagulants prior to surgery? Well, this is really a bit of a thorny problem and it comes up regularly. I commonly get phone calls from GPs and even more commonly from surgeons saying, I want to do this procedure. Can I just stop this medication? And they're talking about warfarin or one of the NOACs. Well, of course, it's more complicated than that. And in my experience, I've now moved to a situation where I think this is a conversation that needs to be had with the patient who's going to undergo the surgery, with the cardiologist who generally is the person who commenced that anticoagulant regime, and then have a discussion about the risks of bleeding related to surgery and the risk of clot forming if stopping the anticoagulant. this is really important because it will go wrong from time to time and that consultation is an opportunity to discuss the pros and cons to discuss the timing of alteration of that anticoagulant regime and it's also an opportunity to document an understanding from the patient that there is a no zero risk position in going through surgery if you need to reduce or hold anticoagulation so I tend to use those opportunities as a consent to procedure and an understanding of the risk and benefit. It turns out that sometimes patients come and see me and it's been quite a while since I've seen me as a cardiologist so it's a great opportunity to do a little bit of a tidy up and a bit of maintenance as well so more than one good reason to touch base and make sure everything is is lined up as well as possible for an upcoming surgery. My recommendation, don't just stop the anticoagulants without really deferring to someone who knows the risks inherent with stopping that anticoagulation and without deferring or giving that patient actually, deferring time-wise to allow that patient to have the conversation about the risks and benefits so that they understand it as well. Well, that's a little bit on blood thinners. I hope you found it interesting. If you have any queries or questions, please feel free to drop me a line. For now, I'm going to wish you the very best. Take care and bye for now. Did you know that coronary artery disease kills one in four people? So most of us are likely to carry some risk or know someone who does. If you're interested in finding out more about how to evaluate that risk, check out. www.virtualheartcheck.com.au It'll give you information about risk and what else can be done to be even more precise.
