Types of aortic valves available.

What kind of valves can be used for an aortic valve replacement? Generally the artificial valves or the prostatic valves that we use for replacing the native valve are categorized into two major classes. You have the metal valves or the tissue valves, the biological valves as we call them. So the metal valves are the mechanical valves, They are generally meant to last forever. They usually are offered to patients who are younger than 60 years of age. And the whole philosophy about offering them a mechanical valve is that you will not be undertaking a further surgical operation to replace this valve during their lifespan. Obviously, these valves are made of a pyrocarbon compound. which is thrombogenic, which means that when you implant this valve into the body, there will be a tendency for clots to form on this valve. Hence, to avoid that, patients would require lifelong anticoagulation, which essentially means that they would need to take a blood thinner for the rest of their life. Now, that may not be something that a lot of patients would like to have, and hence they can opt for the second type of valve, which is called a tissue or a biological valve. Before we talk about the biological, the tissue valves, it is also important to mention that the metal valves, they also make a ticking noise, which sometimes can be quite annoying for certain patients. And hence this aspect needs to be discussed with the with the patient before the valve is implanted. As I'm aware of patients who've come back and have requested that this valve be taken out and replaced with another valve. So I think this is a very important bit of information that must be shared with the patient when they are selecting the type of valve that they're gonna have. The second class of valve are the tissue valves and they are broadly classified into two or three categories. Um, there's the commonest category that we use at the moment, uh, valves, which are called stented valves. These basically are artificial valves, which are generally made out of, um, the heart lining of a cow's heart. Um, and these are also called the pericardial valves. Um, they are the most commonly used valves at moment. They are very durable and they normally, if implanted in a a patient who's 60 years or older would still be working in 85% of the patients at 15 years. So, generally these tissue valves are offered to patients who are 60 years or above and they give them a good 10 to 15 years worth of lifespan. After that, they would require a further operation because after 15 or 18 or 12 years, depending on individuals, these valves tend to degenerate and then they would require either a further operation to replace them, or at the moment, there's a lot of work happening whereby you can put a trans catheter or a TAVI valve inside these valves without cutting you open. So that option is there, and that is one of the other reasons why biological valves are now becoming very popular with patients, primarily because They do not require lifelong anticoagulation or intake of blood thinners, which means that there's very little impact on your quality of life. And secondly, because they do not require a further operation and most of these valves can be treated with transcatheter approaches. Hence, patients are now opting for these valves, even at a younger age. However, patients need to be mindful that if they opt for a biological valve at a younger age, then they will require further intervention. And if patient is relatively young, say in their 40s, and they offer a tissue valve, then they're looking at potentially at least two, possibly three further interventions during their lifespan. So these are important discussions that need to take place when a patient is opting for a valve. A lot of the patients opt for a biological valve because of the fact that they don't want a major impact on their lifestyle. For example, if someone is involved in contact sports and they're at a younger age group, they would opt for a biological valve because a mechanical valve would preclude them from taking part in contact sports as being on a blood thinner increases their risk of having bruises and hematomas, as we call them. and hence that means they would not be able to take part in the sports that they're doing. Also, if you're someone who's involved in an occupation where they're at risk of cutting themselves or injuring themselves at work, then they're generally advised not to go for a mechanical valve because being on a blood thinner can potentially increase the risk of bleeding. However, these decisions are generally made by the patient based on their preference and obviously advice from the expert. Another type of biological valve that we use occasionally is called a homograph, which is a valve that is taken out of a person who's died and this valve is then removed from their heart. This valve is generally reserved for patients who have infection on their native valve, something called endocarditis. In endocarditis, we would normally offer them a homograph or a valve taken out of a dead person's heart. And the reason for it is that these homographs seem to be resistant to further infection. Hence, instead of putting in an artificial valve, which is either a mechanical or a tissue valve, we tend to prefer a homograph. However, these views are also now changing. And I think there's a lot more evidence coming out to suggest that the choice of artificial valve does not necessarily have an impact on whether the infection recurs or not. But some institutions, some hospitals have a preference for using homographs in patients who have infection on the native valve.