WHY heart stents FAIL?

great to be with you it's peterbal I see a cardiologist now one of the more common topics and videos that we've had as part of the channel relates to heart stents and just a quick thank you to everybody that's clicked and watched it and great to hear that you have found it useful but a common question and comment that I often get asked is how long do heart stents last while answering that is like answering how long is a piece of string there are so many variables that we can't provide you with a you know prediction but what I want to do today is to go through three broad categories that we know lead to stints failing [Music] so as you would know heart stents are little devices that are used to prop open blockages inside the arteries of the heart they can be used at the time of somebody having a heart attack or for patients who have stable symptoms called angina where you might have pressure in the chest shortness of breath particularly our binclines upstairs with physical activity that is not responding to medicines while stents can be useful to improve blood flow and therefore symptoms and since nowadays are very very safe the risks of stents are very low but they're not zero anytime we implant a device personally in the body while there are inherent complications that can arise and to categorize these complications I want to provide you with a framework of how I think about the topic of stints failing or stint re-stenosis where the stent develops this excess scar tissue inside or stents can suddenly fail with a condition known as stent thrombosis where that might be a bit more emergent and the risk of a heart attack is high if the artery fills up with clot at the level of the stent and it's crucial that gets fixed up urgently now I want to divide these complications and why stents fail in three categories first I want to focus on well the patient factors so what are some of the factors that are relevant to the patient that may make the stent more likely to re-narrow secondly I want to focus on stent factors themselves so the devices that we're using and features of the blockage that we use to treat the problem well there are some issues that can arise instance as a result of the type of blockage that we are trying to open up and thirdly procedural factors and they are factors well in short their factors relevant to the cardiologist that places the stent and will delve into a few of those so patient factors well why will stents fail stents will fail if we don't maintain them if we don't look after them and I often tell my patients that the easiest part of the stent is actually putting the stent in in the first place but then it's the many many years and Decades of life that we have to maintain the stent and how do we maintain it well we know that patients with diabetes are at a slightly higher risk of developing complications inside stents so of course controlling diabetes appropriately well will significantly reduce the risk we know that patients with chronic kidney disease are also at a higher risk of developing complications inside stents patients who may not be compliant or taking the appropriate medication and there are a series of medicines that we do prescribe after we use and we place a stint to help reduce the risk of the stent filing or developing a complication such as a clot formation and these medicines often use to stop these clots forming aspirin Clopidogrel ticagrelor some of the drugs that we use and we use them for a specific purpose in that in the initial phase in the first few months of the stent being in the body well there is no tissue overlying the stent it's a plain you know metal metal extent that's floating inside the artery of the heart well we need to suppress the body's reaction against the stent and the risks of developing clots inside that stent as the stent heals inside the body while these blood medicines these blood anti-cot medicines are crucial that we remain on and if we don't well there's a higher risk of developing a complication known as stent thrombosis where the stent May block off also not remaining on other types of medicines and in particular a couple of specific types of medicines have been shown to reduce the chances of building up cholesterol and blockages inside stents and they are statins so there's a lot said about statins and I understand that there are people who have very very strong views about statins but there is a notion that if we can reduce the blood levels of cholesterol and therefore reduce the accumulation of cholesterol plaque inside while the region of where we've put the stent in the first place we can reduce the risk of re-naring and that re-narrowing is a process known as Neo atherosclerosis where new plaque forms inside the stent over time and by taking statins we significantly reduce that the statins also reduced a process known as inflammation and inflammation is also very very important at causing cholesterol to become more active and to disrupt and to cause complications while statins can reduce that managing blood pressure so of course the higher the blood pressure the more risk of developing re-narrowing inside stents but also the risk of developing further blockages in other parts of the artery so controlling that is Paramount stopping smoking cigarette smoking is unfortunately one of the key factors that does lead to stents failing stents forming an excess amount of tissue or scar tissue inside can cause restonosis and that can then bring on more symptoms chest pain shortness of breath and obviously has an impact on quality of life so we know that cigarette smoking is a strong predictor of why a stint may fail so there's some of the patient factors again complying with medication having diabetes chronic kidney disease so smoking not controlling blood pressure not controlling blood levels of cholesterol and not complying with medication they are all factors that mean that you are a slightly higher risk of developing complications inside your heart stent now the second part I want to focus on are extent factors or blockage or lesion factors and these are factors that are relevant to your individual arteries and where the blockage is actually formed and then the types of stints that we're using because there are we know some factors that do lead to a slightly higher risk of stents failing the type of scent and we had a recent video on the differentiation between Bare Metal stents and Drug eluting stents well we know that with bare metal stints where there's no drug coating around that that inhibits the body's reaction against the stent there is a higher risk of re-naring and re-stenosis inside the stent with bare metal stints it's not to say that we can't achieve excellent results with bare metal stents we can't but we know time and time again that if bare middle stands are used compared to the more traditional now drug eluding stents or dry coated stents then there is a higher risk of renaring and therefore bare metal sense are probably not indicated at present given the great results that we're able to achieve with this drug eluding stents with a significantly lower risk of complications so treating blockages that occur at bifurcation lesions and we've had a separate video on bifurcation lesions themselves and these are blockages that build up inside Branch points of arteries so when you have a blockage that forms in a rather complex part of an artery that has a branch Point while putting stents in that type of blockage versus a blockage that occurs in a single or a straight part of an archery with no Branch there is a slightly higher risk of complications and re-narrowing treating calcium or calcified lesions when the arteries have got this material that essentially makes up our bone and our teeth calcium and over time they can build up and it becomes almost like a rock a material becomes so hard that we've often got to use very high pressure balloons to try to stretch and crack that calcium open so we can put stents in but we often have to use these drills inside the artery to shave off some of the calcium to allow us to be able to expand this tint is that when we implant stents in these very calcified arteries there is a slightly higher risk of re-naring purely because of the forces that are exerted by the calcium can mean that these stents may be at a slightly higher risk of renaring at that level of where the calcium is another site relevant to the arteries is if we put stents into arteries where there are bends and not small bends but when I'm talking about bends I'm talking very sharp bends or Kinks and Our arteries are all unique but if blockages do develop in areas where the arteries are bending and we put a stent or a scaffold inside that area well you can imagine over time as the arteries beating every heartbeat and that motion of the coronary artery can often lead to a condition known as stent fracture where the stint material starts breaking and starts fracturing and that can be a reason why the stent can develop re-narrowing at that site and start giving you more symptoms and finally I want to cover factors that are associated with the procedure itself and as Interventional cardiologists you know around the world we strive to achieve an excellent result for all our patients but there are some risks that are inherent with this procedure so for example one of the more common reasons why a stint May Fail in the immediate sort of few hours after a procedure and you might have had the stint in and you had to go back and be rushed back into the procedural laboratory because you've developed significant chest pain and changes on your your electrocardiogram is a condition known as a dissection and dissections are little tears in the walls of the artery that are initiated by us putting balloons and putting these stents inside the archery and we create these microscopic little tears and Trauma in the archery but most often that heals and settles down particularly when they are very very microscopic and small the body just heals naturally but if these little tears occur at the edge of where we've put the stent in and that tear is having an impact on blood flow well that can acutely cause a clot formation inside that part of the artery and inside the stent meaning that we have to urgently go back in to put a further stint to cover that area that had that little dissection to ensure that can heal safely and Achieve an excellent result long term another procedural factor is stints that are not sized appropriately to the artery and that is a challenge when the archery for example might be large in caliber and all our arteries are very unique but if the archery for example at the top part of the the one of the key arteries of the heart is about you know four or five millimeters in diameter and there's a blockage there well we've got to ensure that we use the appropriate size stint to ensure that the stent is fully expanded inside that artery if we use a smaller stent a smaller diameter stent well then you can imagine that stent isn't fully expanding that large artery and that is a reason why stents can re-narrow and why they can fail and here's an example of an artery that has had a stent placed but this was a relatively small stent that was put in and over time because of that mismatching the size of the stent versus the size of the archery there was a complication in restonosis re-narrowing about 90 blockage are developed inside and I needed to go and put another stent to fix that up so in this video we've covered a few key factors that lead to stents re-naring or failing this is a very complex topic but an important one and this I hope has given you some framework some better understanding that putting the stent in of course is an involved process requires your doctor to have the relevant experience to be able to size the stent appropriately to get a very good fit into your archery but then there are also those additional factors of trying to you know improve diabetes reduce blood pressure reduce the cholesterol levels in the bloodstream stop smoking and those key lifestyle factors that will ensure you achieve a stint that lasts forever thanks for joining me I hope you found that useful until the next video bye for now

Channel: Heart Matters

Views: 261,097

Keywords: cardiology, heart stent, stent restenosis, stent thrombosis, ami, atherosclerosis, cholesterol, plaque, coronary stents, risk of coronary stents, clopidogrel, blood thinners, why stents fail?, heart matters, Prof Peter Barlis Cardiologist, angina, heart attack, safety of heart stents

Id: igjBBcybOhs

Length: 16min 19sec (979 seconds)

Published: Thu Nov 03 2022