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Aortic Stenosis and the urgency for treatment

Welcome to this evening’s aortic stenosis and the urgency for treatment webinar.  My name is Dr Trish Kahawita and I will be your host for the evening.  Before we get started, I would like to acknowledge the traditional owners of the lands from where each of us is joining this webinar today.  I wish to pay my respects to the elders past, present and emerging.  Just a few housekeeping notes, this webinar is being recorded and you will receive a copy in the coming week.  If you cannot see this control panel on your screen, move your cursor over the bottom of your screen and the panel will appear.  The control panel provides you with the audio tools for adjustment and is where you can ask questions via the Q&A module.  We have put everyone on mute to ensure learning will not be disrupted by background noise.  If you need assistance, please use the Q&A feature to raise any technical issues and to submit your questions throughout the presentation.  We will be addressing questions throughout and after the presentation in the dedicated question and answer time.  You can upvote the questions by selecting the tick icon on a question, this will assist in reducing the amount of same or similar questions being submitted.  Tonight’s webinar is proudly supported by Medtronic and our presenter this evening is A/Prof is Dion Stub.  A/Prof is Dion Stub is an interventional cardiologist specialising in coronary and structural heart intervention.  He also has a particular interest in treating the cardiac emergencies of myocardial infarction and cardiac arrest and was awarded his PhD in 2013, developing Australia’s first treatment pathways for patients with refractory cardiac arrest through combined research at the Baker IDI Heart and Diabetes Institute and the Alfred Hospital.  He is a staff specialist at Alfred Hospital and Western Health and has rooms at Cabrini Hospital, Malvern.  We will get started now and I will hand over to Dion to commence his presentation.  Thanks Dion.
 
4:18
Thanks Trish and thanks to the RACGP, yeah, absolute pleasure to present you this evening.  Just a shoutout to my New South Wales colleagues who are stuck in lockdown, I think being from Melbourne we very much empathise and wish you a speedy out of lockdown, it’s a frustrating time for us all really and presenting unique challenges within the healthcare sector, that’s definitely had an impact on cardiac disease and we could spend the hour talking about the ramifications to heart health and I definitely think it has impacted out all the population with a specific topic in today we will be talking about aortic stenosis, the urgency for treatment and it is a very specialised topic and selective topic, but I think they are very relevant and important and in particular because of the massive and fundamental changes that have happened over the last decade and some of the challenges that we still face in Australia.  In terms of my disclosures, the biggest is the length that I present from as an interventional cardiologist specialising in aortic stenosis and offering transcatheter therapies that come with my own unique approach, which may be a little bit different to my cardiac surgical colleagues, but I will try and present a holistic and a complete picture to the challenges and options that we face with dealing with our patients with valvular heart disease, and I have grateful support from the National Heart Foundation for ongoing research.  So, in terms of the plan for today is really to give a wholesale look at the problem of aortic valve disease, in particular aortic stenosis.  We will talk a bit about from a primary care perspective, how important you are as the gatekeepers of really detecting the disease, monitoring it, like all things knowing when to call in specialised services.  We will talk through signs, symptoms, issues with recognition, some problems with delay to therapies that both happen from a patient perspective, primary care perspective and specialist perspective.  We will talk a bit about the heart team and shared decision-making and then go through some of the wealth of clinical evidence that we have when it comes from aortic stenosis.  As _____ very happy to take questions during the talk and then we will spend a bit of time at the end going through further questions you have.  So, I thought I would start with a case that illustrates how this treatment has evolved, typical patients and then some of the frustrations we have, so these are fairly typical patients that you will see in primary practice and very typical to patients.  I see this 75-year-old otherwise well male, high functioning, still working.  So, even though aortic stenosis is a disease of the elderly, significant numbers of our older patients, where they have been late 60s, mid 70s and even our 80-year-old patients will still work and be extremely active and so really important when it comes to patient-based decision-making and the kind of outcomes that patients are wanting from their therapies.  He had known aortic stenosis that had been watched for a number of years and we will talk about monitoring that throughout the presentation, that had definitely now become severe, so we will talk a bit about the criteria, but on his echo he had a gradient of 60, an aortic valve area of 0.8, still had preserved systolic function and started to describe New York Heart Association II dyspnoea and I will focus a lot on that, it’s one symptoms begin that really the transition from being a benign condition to something quite lethal begins.  Had had a workup for his aortic stenosis with mild coronary artery disease and this is all on the background of being an extremely well 75-year-old with only hypertension and dyslipidaemia.  And what happened to him is he is becoming increasingly typical to what our patients are facing and in essence, due to the change in technology and treatment for aortic stenosis, both providers, whether they be primary care providers or cardiologists, are faced with a lot of choice and those choices often lead to confusion, so this patient had a longstanding cardiologist, who recommended the time was right for aortic valve replacement, he recommended he go see the surgical colleague, so he saw a cardiothoracic surgeon.  He recommended that he have minimally invasive surgical aortic valve replacement with a mini thoracotomy.  This patient, like many increasing numbers of patients, had had a friend who had had an alternative therapy, which was TAVI, transcatheter aortic valve implantation, and so he asked if he could see another cardiologist, so he saw a second cardiologist who recommended that he go and see a third cardiologist, who was me, as the TAVI specialist, and I said, well why don’t we finish the workup with a TAVI CT, we will talk a little bit about how important anatomy is to making decisions.  He then saw a second cardiothoracic surgeon.  We will talk about the heart team and the regulations within Australia and how we need a consensus at the moment still for a patient to undergo TAVI.  And so finally, after seeing three cardiologists and two surgeons, the patient had the therapy and clearly, when we are talking about any disease process, it really shouldn’t be this hard.  So, the patient then underwent TAVI, just to orientate you from a procedural point of view, most TAVIs around Australia are done with local anaesthetic and minimal conscious sedation.  They are done percutaneously, so that means there is no cutting involved, it’s all done with needles and wires and in a vast majority of patients this is done through the femoral artery, ultrasound guidance, we access the common femoral artery and femoral vein.  Most procedures, depending on complexity, would be anywhere from 45 minutes to 60 minutes.  He was fairly straightforward so he had a 43-minute procedural time, minimal amount of contrast, and in terms of orientating you, this is the aorta, this is the aortic valve calcified, this is left ventricle, there is a wire, a very stiff wire sitting in the left ventricle and then this is the self-expanding TAVI valve that we implanted narrow, so it is narrowed in its shape that allows us to access it through a 16 French sheath, and then we gradually unsheathe it until we are left with… he had a large annulus and so we ended up inserting the largest type of TAVI valve with a 34mm valve and you can see excellent final position, no aortic regurgitation and essentially after 43 minutes you have an instantaneous curing of his aortic stenosis with his gradient going from 60 down to 8, which is a great result post any bioprosthetic valve, trivial aortic regurgitation.  I will talk a little bit about the issues with TAVI, one of them being we monitor closely for heart block and need for permanent pacemaker.  This patient did beautifully, was walking on the same afternoon, so this is really important, almost all of our patients sit up out of bed and are walking that evening.  As I said, all done with local anaesthetic, particularly important with all the patients that may have a degree of early cognitive impairment.  Normal haemoglobin.  Creatinine 80.  Was discharged home on day 2.  I worked in Canada for a number of years where this technology was invented and they send their patients home on day 1.  Most Australian patients prefer to spend the first day walking around and monitoring in the hospital and so in most units if patients are doing well patients will go home day 2 or day 3 and this patient, 75, still working, was essentially straight to the office even though we did advise him that he couldn’t drive for a couple of weeks.  So, this has really transformed the paradigm for patients with aortic stenosis where for the last 30 years it was excellent results, but it required a midline sternotomy, cardiopulmonary bypass, a week in hospital potentially needing to go to rehab and taking months until quality of life was restored.  It has really transformed therapy.  So, we will sort of take a step back and work out who is it that we have to consider for this therapy.  So, in terms of aortic stenosis, it is the most prevalent native valve disease, I am sure many of you would see significant numbers of patients with varying degrees of aortic stenosis in your practice, a few percent of patients at the age of 65 will have it, but 4 to 5% of patients over the age of 80 will have calcific aortic stenosis.  Rheumatic is really no longer an issue in most Australians for our first nations, it is still unfortunately an issue as for some migrant populations, but the vast majority of patients with aortic stenosis will either be calcific degenerative or the congenital form which is bicuspid aortic stenosis and for those with bicuspid aortic stenosis they usually present with issues 10 to 15 years before calcific degenerative, but the vast majority of patients with aortic stenosis are calcific degenerative.  Most of the risk factors would be very similar to the risk factors with coronary artery disease.  I will talk a little bit, however, how unlike with coronary artery disease where we have fabulous medical therapy which can change the prognosis of the condition, we don’t have any medical therapy with AS, a mechanical condition that really has only one mechanical solution.  So, in terms of the problem it is absolutely a benign condition in its early stages and so for many years our patients we may pick up a degree of aortic sclerosis where we just hear a soft murmur in the patient's late 50s or early 60s and we know when it is mild and moderate it is absolutely benign, but once the aortic stenosis becomes moderate plus or moderate to severe severe and then absolutely when the patient develops symptoms, the condition transforms fairly radically where we have a benign condition in its early years to becoming an absolutely fatal condition unless treated, and unfortunately we put down a lot of early symptoms to aortic stenosis to the ageing process, so very early symptoms for AS will be lethargy, some tiredness and then potentially some very mild shortness of breath and so many patients will just put that down to being slightly unfit and getting older and so a careful question I ask all my patients when I am monitoring their AS is how do they feel three months, so now compared to three months ago or now compared to six months ago and their energy levels change, their ability to walk up a hill, do their activities of daily living, how has that changed, and so, it is still an issue and it does not matter what study you look at, whether you look at studies that have done in south-east Asia, Europe or America, I think if we took one message away from tonight is that in all parts of the world wherever we have studied at a population level aortic stenosis, this problematic stubborn number of 30% of patients are being left untreated, and so this is clearly room for improvement where all parts of the world we still have a significant number of patients with aortic stenosis with an absolutely lethal disease.  So, this is comparing severe symptomatic untreated aortic stenosis for a whole series of cancers and you can see, it is absolutely a terminal condition once it becomes severe and once you develop symptoms.  Now, for many of these patients that are untreated, a small percentage we would say, it may be appropriate, I will talk about frailty and so a 90-year-old patient with advanced dementia who is doubly incontinent in a wheelchair at a nursing home, it may be absolutely appropriate for them not to be referred for an aortic valve replacement, but that’s a relatively small percentage when we are looking at these studies, and so there is a significant proportion for a whole variety of reasons that are being left untreated, and I think this is clearly the group in Australia that we need to work on.  We have hinted already about how the patient presents and I think an assessment … and one of the takeaway message is we will talk a bit about the heart checks and the assessment for aortic stenosis is very much like the assessment you would do for any older patient when screening them with regards to whether the coronary disease, hypertension or heart failure or valvular disease, the symptoms and risk factors that we look for are all very similar and so as our patients age, start thinking more about coronary disease as well as valvular heart disease.  The gender has an issue, but we do know that females post menopause, in particular with regards to coronary risk factors, start mimicking ____ detected pre menopause and then smoking, hypertension, dyslipidaemia, all significant parts that we want to pick up with coronary disease.  They have similar risk factors with regards to valvular heart disease and aortic stenosis.  In terms of the symptoms, in medical school we are taught about the classic triad of aortic stenosis being dyspnoea, angina, and syncope, clearly I think if we are waiting for our patients to become syncopal, this is an end-stage issue and clearly I think we definitely left things too late, but the earliest symptoms for aortic stenosis already alluded to are fatigue and dyspnoea, that absolutely once patients have become dyspnoeic it is definitely time to start thinking about what are the next steps.  In terms of the signs, it is the easiest murmur to pick up, it is a crescendo decrescendo, which is the harshest of the murmurs that you would hear, it sounds a lot harsher than the pansystolic murmur or mitral regurgitation.  In terms of severity, the length and lightness of the murmur, there are more subtle features that I think in the age of echocardiography that subtle art of auscultation is disappearing, but definitely picking up a harsh-sounding murmur loudest in the aortic region radiating to the carotids, fourth heart sound again is a late sign that would be a feature of significant severity, plateau pulse again is a decreased impulse of the carotid pulse, is again a key feature of severity, it is the finding _____ gradient clinically, but definitely any murmur, the murmur of aortic stenosis can often be heard throughout the precordium, so it may be loudest at the aortic region, but you can actually hear it in many patients all over the chest even when you are auscultation lung fields posteriorly, you may often hear the transmitted sound due to the crescendo decrescendo nature of the murmur.  So, I think one of the other messages that any patient with a murmur I think should have the murmur quantified with an echocardiography.  I think this is a really fabulous initiative , it’s been around now for a few years, the ability for dedicated item number within primary care for a heart health check and when we are thinking about our older patients with valvular heart disease, clearly all the patients that we are talking about would fit within this heart check, as I said, valvular heart disease, in particular aortic stenosis, is typically a disease of the elderly, but patients with bicuspid congenital aortic valve disease can present earlier.  I have got a few patients that I have referred for intervention in their 40s.  We will talk about how those kind of patients would clearly need a surgical aortic valve replacement, but from a heart check perspective you meet criteria for a heart check if you are over 45, without known cardiovascular disease, but people with known cardiovascular disease or already established valvular heart disease, they wouldn’t be fitting in the heart check.  And then in terms of frequency of echocardiography, I think if you are very stable and you are monitoring your hypertension we are looking at left ventricular function and left ventricular hypertrophy, stable coronary artery disease, then an echocardiogram every two years is adequate.  I think it is very useful looking at the change.  It is an ultrasound, there is no radiation, but for patients with more advanced valvular disease, so when you are moving from mild-to-moderate aortic stenosis then I think moving to an echocardiogram every 12 months ____, so we do not miss that early window for intervention would potentially be more appropriate.  So, in terms of assessing the severity, when I lecture medical students and residents, I tell them there’s not many numbers to remember in cardiology.  When we think about left ventricular function the number of ejection fraction of 35% is the magic number when one’s thinking about heart failure.  For aortic stenosis, the magic number is a mean gradient of 40 and an aortic valve area of 1.  Once the patient has a gradient above 40 and an aortic valve area of less than 1 is considered severe aortic stenosis.  Unfortunately, like most areas of medicine, patients don’t fit into nice and neat groups and there is a significant proportion, almost 50% of patients, will have numbers outside of those ranges, but still deem to be at severe aortic stenosis and the reason is because of these issues around low-flow states, so whether a patient has significant diastolic dysfunction and therefore low cardiac output and therefore the gradient may be lower than 40, but they still have severe aortic stenosis.  For patients who have systolic heart failure, whether it be from prior myocardial infarction, so their heart just can’t amount that gradient, so they may actually have a gradient of 20 and an ejection fraction of 30 and still have severe aortic stenosis.  So, in some patients it can actually be quite challenging to work out whether the patient has moderate or severe aortic stenosis, we are using other tools such as stress echo or dobutamine echo and then more recently, calcium score with a CT where I think most of us would be familiar with calcium score of the coronaries and that guides the need for things like primary prevention statins or actually starting out to do calcium scores on the aortic valve, and that can be very useful when the diagnosis is a bit tricky, is this moderate AS or is it severe, but that would often be once the patient has met a cardiologist, but even a specialist within the area it can be hard to tease out in particular with comorbid patients what is truly moderate AS versus severe and it has significant implications for pulling the trigger on therapies.  So, in terms of the other key message, which I have hinted at already is that in terms of your following your patients for a number of years with mild to moderate aortic stenosis, remaining completely asymptomatic, one of the big messages is when to refer to your friendly cardiologist, is when the patient has severe aortic stenosis, which will clearly be a change in the conclusion of their echo reports, and I have hinted at what some of those numbers are, gradients about 40, valve areas below 1, and in particular when the patient develops symptoms.  So, if you have your 75-year-old who swears black and blue, still mow their lawn with no problems, ride their bicycle for half an hour and really have no limitations at all, that is clearly an asymptomatic older patient and therefore there is no rush for intervention, but once you get severe aortic stenosis with symptoms, it is class 1 indication to consider aortic valve replacement.  It is tricky, I think like most areas in medicine, we don’t have a lot of evidence when the patient is asymptomatic, that’s for much of cardiology, whether to be asymptomatic coronary artery disease or asymptomatic valvular heart disease.  Clearly with coronary disease, we know medical therapy is useful, there is no medical therapy that changes the prognosis of aortic valve disease and so for our asymptomatic patients it is tricky.  It is also hard because, as I have said, this is the disease of older Australians and they often have comorbid conditions, so a classic comorbid condition is osteoarthritis, limited mobility due to hip pain or knee pain, and therefore they say they are completely asymptomatic, but are really hard to tease out because they are just not walking as much as they used to be.  When I went through medical school it was considered a contraindication, if you had aortic stenosis you shouldn’t have a stress test.  We now know that that’s not the case and that a careful Bruce protocol stress test or a regular stress test that is done carefully can be incredibly useful in patients with aortic stenosis and they use it a lot in my asymptomatic patients that now have moderate AS or approaching severe AS.  Are they truly asymptomatic?  And so patients may say that they have no symptoms, but when we put them on a very gentle treadmill and within a minute they are huffing and puffing, then clearly their definition of asymptomatic is quite different to what I might consider asymptomatic, and we know prognostically, if you develop symptoms early in your stress test, you behave very much like a patient with symptomatic aortic stenosis, and therefore we should consider intervention.  The other interesting thing is this concept of asymptomatic severe AS and there has been some more, I suppose, provocative data that has come from a large echo database that is even hinting, which I haven’t presented here, but it’s even hinting at moderate aortic stenosis, that maybe we are waiting too long, and that for patients with asymptomatic severe AS they have a worse survival and a worse outcome compared to patients that undergo aortic valve replacement and potentially that applies to the moderate or at least the moderate plus group.  So, I suppose the message is once your patients have moderate to moderate to severe aortic stenosis and certainly start reporting functional decline, that we need to think about referring for at least consideration of a discussion to meet a cardiologist and then thinking about the workup to look at anatomical suitability for the variety of possibilities.  And so, this is another issue on the theme, I will hint a bit about the difference between public and private system in Australia, there are some unusual issues where it is perversely easier in some aspects to have treatment in the public system than the private system at present, but there’s definitely a cost on the waiting list and we know that we see not huge numbers, but small numbers of patients, this was an American study, we saw similar data when I worked in Canada and definitely similar, in our own experience in Australia, that there is a cost on the waiting list and the patients will unfortunately be waiting too long and so this is clear if you are dying on the waiting list waiting for your aortic valve replacement then there is clearly an issue around potentially referring too late and that we needed to meet these patients earlier in their disease process.  So, in terms of therapeutic options, as I have hinted at from the outset, it’s a mechanical condition that has only one mechanical solution and that is an aortic valve replacement and so the issue is that over the last 30 years where it was 20 to 25 years ago, it was simple from a decision perspective, we had a surgical aortic valve replacement and the biggest decision was to put in a tissue or a bioprosthetic valve or do you put in a mechanical valve, and so now we are left with do we have a surgical aortic valve replacement and within that should we have a minimally invasive surgical aortic valve replacement or should we have the traditional midline sternotomy, should we have a bioprosthetic or a mechanical valve, so despite the new and novel direct oral anticoagulation agents sort of transforming anticoagulation in atrial fibrillation, they haven’t been used yet in mechanical valve, there’s been one trial, but at the moment if you have a mechanical valve that is usually reserved for younger patients, essentially it’s lifelong warfarin and so for many patients that is a massive ask and so we know there has been a big trend both in Australia and internationally, _____ that increasingly patients are asking for bioprosthetic valves, so where anyone under 60 used to get a mechanical aortic valve replacement, increasingly 50-year-olds that need aortic valve intervention are asking not to have a mechanical aortic valve and they want a bioprosthetic valve, which has implications for lifelong decision-making.  And then the big change in Australia and around the world, which is now 11 to 12 years old, we have had a decade of transcatheter aortic valve replacement, which has really revolutionized, I have already hinted, that has completely transformed decision-making and so for patients, when I talk to them about the differences between the two therapies, they kind of look at me with bewilderment as to why anyone would ask for a midline sternotomy when they can have potentially a procedure in 45 minutes under local anaesthetic and be discharged in day 2.  Its really important and it can be a very difficult conversation where I actually tell patients for a variety of reasons that I think they should have surgical aortic valve replacement and I will hint at what some of those are, those that have complex coronary artery disease where we don’t think we can get a good job with stents, more congenital abnormalities, bicuspid disease.  Whilst the majority of patients may be anatomically suitable for TAVI, a small percent, maybe 10 to 15% of patients, we may say, no, you should have the traditional surgical aortic valve replacement.  Very similar to the discussion we would have with patients when we are talking about stenting, percutaneous coronary intervention and stenting for coronary artery disease, there’s coronary artery bypass graft surgery.  It is all regarding the anatomy and what we think is best for our patients, not what we can do, but rather what we think the patient should have, and then in terms of other options, aortic valvuloplasty where instead of inserting a valve we will just balloon the valve, is really reserved as a potential breach to TAVI if they complicated or have other issues like sepsis and they have a kind of have a TAVI at the time, or as a palliative measure.  It doesn’t really change the natural history of the disease, but it can be very useful for symptoms.  And as I have hinted already, there is a group of older Australians with significant comorbidities or a particular significant frailty that we just don’t think are suitable for an aortic valve replacement, whether that be TAVI or surgery, so some centres will consider valvuloplasty, again, it is almost a palliative procedure; other centres would say valvuloplasties are a waste of time, and it’s important that we don’t think of age as the limitation, I think this is a great photo that shows both two 90-year-old patients, but very different end-of-the-bed frailty assessments.  Increasingly, we know we can TAVI, that a dedicated frailty scores and frailty tests are very useful, but the end-of-the bed test or sitting beside your bed _____ on your examination table, it can be very clear that one may be a very robust 92 or 93-year-old who is still living at home and independent, versus a much more frail patient where you may be having different more end-of-life care decisions with them and their family.  I think the other really interesting thing that has come out of the whole debate between TAVI, percutaneous aortic valve replacement and surgical aortic valve replacement is this concept of the heart team and shared decision-making.  It is also similar to what would happen in larger centres around complex coronary stenting versus coronary artery bypass graft surgery, but it is a mandated component of TAVI in Australia, which I think has its pros and cons, but essentially in Australia you can’t offer somebody a TAVI until they have gone through a heart team and in one sense, that is a good thing so that all patients in Australia if they are being considered for TAVI, have to be presented at a heart team, it’s interesting that the converse is not true, but you can have a surgical aortic valve replacement without going through a heat team, but I think that’s more of a historical thing, but the heart team is where you get an interventional cardiologist and a surgeon and then someone who is not involved in the case that can talk through the issues whether they be anatomy, comorbidities, look at all the pictures and make a recommendation for what they think the best is anatomically for the patient.  The other interesting thing within the regulations are there is nothing at the moment with regards to patient preference, which is also unlike any other condition in medicine.  So, in terms of what’s the revolution, well, the revolution is that we now have the ability of a patient’s procedure done with local anaesthetic and that is TAVI which really has dramatic implications for their recovery.  When we looked at quality of life studies, it takes patients 6 to 12 months post surgical aortic valve replacement to achieve the quality of life that the patients will have within a week of TAVI, so it’s very clear that it has revolutionised therapy around the world.  It is no longer an experimental therapy, we have done it for over a decade approaching 12 years now in Australia, over a million patients have been treated, over 15,000 patients in Australia and New Zealand and essentially every country that offers surgical aortic valve replacement now offers TAVI, and I will show you some figures where you will see there is a significant trend where TAVI has now overtaken surgery with regards to the preferred option.  The other really interesting thing and I think because of the debate between really the two service providers, is that I think it is safe to say that there is no other procedure in medicine, and I don’t think that’s an exaggeration, that has undergone seven large randomised controlled trials, international randomised controlled studies that have looked at one surgical technique, which is aortic valve replacement and compared it surgery to TAVI, so they have looked at patients that are prohibitive, that couldn’t have surgery then they looked at patients that were high risk for surgery then they looked at intermediate risk for surgery and then they finally did low-risk surgery, and I suppose whilst being incredibly frustrating as a provider, it has meant that we have incredibly robust data that far exceeds really any other discussion we have with our patients, we can very precisely tell them with randomised level evidence international class I data what their outcomes are going to be for each individual subset of patients.  The two largest trials that really I suppose cemented TAVI as a therapy considered for the vast majority of patients with severe symptomatic aortic stenosis were the seminal low-risk trials that included both the dominant players in the market that were a balloon expanding TAVI valve as well as a self-expanding TAVI valve.  We are involved in Australia, I think we are almost the highest recruiter outside the United States in one of the trials and the two trials were interesting, run by two separate companies with remarkably similar results that I think provided significant external validity to the results and this is on the back of already five other very large randomised controlled trials in more higher risk patients and showed that this is consistent theme, which is when we talk to patients they say, well, it’s clearly a no-brainer from their perspective, but we can definitely say that within the randomised trials and if you fell within the randomised trials, again these are for patients who meet the anatomical specifications of the trial, that to have the procedure done percutaneously was both safer from a point of view of death and disabling stroke, as well as the ability to be discharged directly home rather than to a rehabilitation facility with quite dramatic differences in quality of life.  I think the Achilles heel for TAVI is still rates of permanent pacemaker, are still higher in patients having TAVI, in particular with self-expanding valves compared to surgical aortic valves, and so this is really important when we are going through the pros and cons.  For the patients, we do tell them that there will be a slightly higher risk of needing a permanent pacemaker and so for some patients they say they are just terrified about the thought of a pacemaker and then we will talk to them about other options, but an important part of the consent process.  So, in terms of now we have large randomised trials, significant _____ analysis, I mean it is very reasonable that we can say of these large randomised trials with TAVI compared to open heart surgery, that you have death, less stroke, less major bleeding, less renal injury, less peri-procedural atrial fibrillation, significant differences in quality of life and length of stay, with the main downside being high permanent pacemaker rate and potentially slightly more aortic regurgitation, but again that is much less an issue with our newer technology valves.  The other interesting thing which I think is really important when we are starting to think of expensive new toys in medicine, in particular in cardiology where it does feel like every few years we invent a new expensive prosthesis whether it be new pacemakers, defibrillators, ablation procedures or implantables, that looking at the cost effectiveness is really important and fundamental to moving forward.  TAVI is one of the very rare procedures where its new and on the initial it looks that the TAVI valves are more expensive when you buy them off the shelf compared to the surgical aortic valves and so on the day of the procedure the TAVI is more expensive than surgery, but due to the benefits of reduction in length of stay, dramatic reductions of ICU, 99% of patients in Australia don’t go to ICU.  When we look, we have looked at, now we have published two papers, both in international and local journals in intermediate and low-risk patients, and so TAVI is one of the very new therapies that is both more efficacious, so it’s safer for patients, but it is also cheaper and so if every patient, if we moved every patient to be having TAVI compared to surgery the government would save significantly when it comes to the cost effectiveness of the therapies.  So, not only is it cost-effective, in the vast majority of cases it’s cost dominant procedure, which is unlike many of the other new therapies where we think of cardiology, oncology and haematology, where we are still testing their cost effectiveness, but very few of them are actually cost dominant when they are more efficacious and cheaper.  Haemodynamics is important, in particular with regards to longevity, there is some differences between self-expanding and balloon expandable, but the important message is they hold up very well and the easy answer is they behave exactly like surgical tissue valves, they are just a bioprosthetic valve with a different delivery system.  The other big thing in particular with younger patients, if I started to think about treating 65 and 70-year-olds, is how longer the valves last and the therapy has only been around for a decade, so we really can’t say beyond the decade, but when we talk about the life of a surgical tissue valve we are really only quoting 10 years as they are usually 10 or 15 years max.  The issue is for all tissue valves, when you put them in younger patients, they actually last less than when you put them in older patients, for a variety of both patient and prosthesis factors, but the thing we can say is this is a six-year data, this same trial has now published eight-year data that just came out last week, TAVI valve is behaving exactly like a bioprosthetic valve, so there is no signal towards reduction in longevity with regards to the valve whether you choose surgery or TAVI from a bioprosthetic.  All bioprosthetic valves or all tissue valves will eventually fail anywhere from 10 to 15, if they are likely beyond 15 years, which is quite different as we mentioned at the beginning to our mechanical metal valves that really we say in most cases last the life of the patient, and so if we are treating 65 and 70 year olds thinking about what are the next steps, what are we going to do in 10 years’ time when this valve fails, the wonderful option is TAVI in a failed surgical valve or TAVI in the failed TAVI valve, and so you can even do TAVI after bioprosthetic valve failure, which is a common procedure and even a third procedure, especially if you are thinking of a 60-year-old, but may be treat them when they are 75, 85 and potentially even 90.  And with regards to long-term….
 
42:02
Sorry Dion, there is a question from anonymous relating to that, the question was how available is TAVI for patients who have a bioprosthetic valve such as an Edwards PERIMOUNT 2900 valves-in- valves.
 
42:12
Yes.  So, valve-in-valve procedure is a wonderful option for patients who have a failed surgical bioprosthetic valve.  There are some issues around the size of the initial surgical valve, so if it was very very small, because when we do the TAVI we are not cutting the valve out, it can be an issue, but for the vast majority of patients who have a surgical tissue valve, important not mechanical, we cannot do TAVI into a mechanical valve, but for the vast majority of patients who have failed tissue valves, TAVI in a bioprosthetic valve, so we call that valve-in-vale TAVI, is essentially the preferred option.  It is a big ask to ask all the patients to have a redo sternotomy, so they have to have a second cardiac surgical procedure and so TAVI in a failed bioprosthetic valve is a fantastic option for 99% of patients with failed tissue valves.  There are some subtleties around the type of tissue valve they had and the anatomy of the patient, but it is a wonderful option for the vast majority of these patients and it has increasingly been done because 50-year-olds are wanting bioprosthetic valves rather than metallic valves.  What happens when they are 60 and 65 and they have their valve fail is really becoming an increasing issue and it will be the same we will see in 10 years when our 70-year-olds have TAVI, will need to have to think what’s the next step and so TAVI in a failed TAVI is also very readily done and even the third procedure, again it’s Russian dolls, but there is no reason that you can’t do TAVI in a bioprosthetic valve, so valve-in-valve TAVI and then do another procedure in 10 years’ time, so again, even as a third option.  Again, outside the realms of evidence, but again it has been done in a number of times, and so you definitely _____ when we are really thinking of the life journey of the patient, what’s going to happen over the next 10, 20, 30 years.  Again, when I talk to my patients and say we need to think about what’s happening in 15 years’ time, they look at me strange and say, doc why don’t we just get through this heart operation first, but I think definitely from a decision-making it’s important that we at least think about those next steps.  In terms of local data, we are one of the first centres in Australia at the Alfred, but again similar to what centres in Sydney, Brisbane and Perth, Adelaide, essentially all surgical centres in Australia are now, if you are offered surgery it is very likely that they are offering TAVI, and our centre like other centres in Australia are showing similar to international data, that the TAVI valves are behaving very much like a surgical bioprosthetic valves.  They are not perfect, eventually they all will fail, but they do appear to be lasting 8, 10, 12 years plus.  I think the longest we have at the Alfred I actually think is the longest TAVI survivor in the world, and we are up to 12 years now in him, he is in his mid-90s.   So, I suppose one issue to touch on that many of you who may have started referring patients to consideration of TAVI is that we do have some interesting rules in Australia that is again almost unique to all procedures in medicine.  I do not think there is any other procedure in medicine that has these caveats to being able to do it.  And so in Australia, you cannot perform a TAVI unless you present the patient at a case conference and the case conference has to deem that the patient is unacceptably high risk for surgical aortic valve replacement.  So, this is one of the most famous people who have undergone TAVI and this was him actually a couple of weeks after his TAVI procedure and so I joked that this was his cardiac rehab performing in the UK on stage, and so, for our Australian rock stars, we have a few ageing rock stars, they can’t access TAVI certainly within the private sector at the moment based on our current MBS rules.  It’s an incredibly frustrating, but this is where we stand at the moment.  The hope is this will change soon due to the overwhelming evidence in both the low and intermediate risk and so because of these MBS rules, if you are 70 and healthy it’s perversely easier to have TAVI in the public system compared to in the private system where you actually can’t because you do not meet MBS criteria, and so because of that if we compare TAVI to surgery compared to the United States and in Europe, in the United States almost three years ago now, TAVI far exceeded surgical aortic valve replacement, if you look at all ______, needing aortic valve replacement, the same in Germany even earlier, they exceeded back in 2014 and 2015.  We are still nowhere near doing more TAVI compared to surgery and so if you look at, these are estimations of public hospital TAVI vs surgery and then in the private hospital similar but we are less than half and so this is around the regulation.  So, despite us being one of the very first countries that actually pioneered the therapy, and we offer fantastic outcomes that are monitored and so you get fantastic outcomes in large volume centres across Australia, they are still because of our regulations we still have to jump through all lot of hoops and it means still the vast majority of patients are having surgical aortic valve replacement compared to TAVI, which is frustrating at all levels, incredibly frustrating for our patients, incredibly frustrating and confusing for our primary care physicians and cardiologists as well as TAVI doctors and surgeons.  But the takeaway messages are that there are benefits to the heart team, it means you should get unbiased opinions as to what’s better, whether the patient needs to have an aortic valve replacement, we have already hinted at the main messages, severe symptomatic aortic stenosis and then what is best for the patient, what‘s their coronary anatomy like, is their anatomy suitable for TAVI, what’s their age, do they have congenital bicuspid disease with trileaflet, do they have anatomical issues that would make surgery very risky, such as a porcelain aorta compared to complex coronary artery disease where they may need bypass grafts vs a couple of stents that could be done before the TAVI and then the TAVI.  So, those decisions really should be on an anatomical level what is best for the patient, much like we do as I have already hinted at, when we are deciding should we do multi-vessel PCI or should we do coronary artery bypass graft surgery, very similar anatomical thoughts to TAVI vs surgery.  So, I suppose just to finish up and for the right time for questions, the big takeaways are that I think we have some work to do to try and reduce that stubborn 30% whether, Europe, America or Australia, we are still missing significant proportion of patients with symptomatic severe aortic stenosis, in fairness I think both primary care physicians and even cardiologists, sometimes underappreciate how terrible a prognosis and that your chance of you being alive in two years with severe symptomatic AS is worse than most metastatic cancers and that is truly a terminal condition, and so really we need to think about appropriate timing of referral and once a patient has moderate plus aortic stenosis, in particular once they develop symptoms, they really need to be referred for your friendly nearby cardiologist for what are the next steps, and they can start making decisions around TAVI or surgery and those decisions are increasingly being sort of dominated by the patients are walking into our offices with preconceived ideas already due to their neighbours, friends and colleagues.  That’s it for me, I am very happy to go through some questions.
 
50:13
Thanks so much for that Dion.  Just in relation to that stubborn 30%, there has been a popular question from Danielle Andersen.  She asks, given no medical management for aortic sclerosis, does it always progress to severe assuming patient lives long enough.  If so why do we wait until severe and symptomatic before a surgical AVR or TAVI, why not operate when younger and perhaps less severe comorbidities.  Is it because of the lifespan of the surgical aortic valve replacement/TAVI?
 
50:42
Yeah, I think that’s a fabulous question.  So, the easy answer is, once you have any amount of AS, once you have ____ aortic sclerosis where you don’t have stenosis, you just have a little bit of turbulence of flow, but once you have stenosis, even if it’s mild so you have a gradient of 10 to 15, if you live long enough, you will develop severe aortic stenosis.  What is interesting is it can progress over a few gradient of five points of gradient per year that you think is very logical and you suspect that is 10 years away from needing intervention, but then we can be surprised and that that it can jump unexpectedly, I think that’s got to do with the nature of the calcium, so it can be completely unpredictable.  That is where you may in the beginning look at two-yearly echoes, but once it progresses potentially move to yearly echoes and even sometimes when I am on the fence about deciding I may even think about six-monthly echoes, if this is still asymptomatic then I am just sort of hedging my bets, so the question is why don’t we go earlier.  I think that’s a fabulous question that cardiology is grappling with that.  There is no, as good as we are procedurally, both interventional cardiologists and surgeons, sometimes I call it is just the procedure meeting the anatomy of the patient and that there is no way to do heart surgery, whether it be TAVI or surgery that’s completely risk-free.  So, the patients will always wear a small risk, we ____ include TAVI now in the order of 0.5% mortality similar for stroke, but so we want to absolutely make sure that the benefit of the procedure outweighs the risks and so if you are asymptomatic and moderate, then we would say at the moment with our best evidence we are happy to wait.  The other benefit to waiting is if it is going to be two to five years until you need the procedure, it means you are five years not needing the next procedure, which is if you are 65 or 70, the chances that you need a second procedure are very very high, and so waiting till you need it is important, but yeah I also showed that we could definitely wait too long and that you need an angiogram, you need to assess your anatomy, patients need to get their affairs in order, you know sometimes they have other issues to deal with, they need screening colonoscopies or they got a polyp, and other medical issues come up, hence there is that window where it may be _____ more severe and the symptoms are not too bad, but it may be better than waiting later, so that’s an emerging field, we have clinical trials at the moment that we are recruiting both in moderate AS and both in asymptomatic severe, trying to answer that question, we definitely know that there are costs for going too late and so the question is at what point should we pull the trigger early, and so I suspect in a few years’ time the message will be… but we are not quite there yet is the easy answer, but once the trials come out I suspect we will know that potentially we should go a little earlier, but I think for most things in cardiology it is very similar with coronary disease, that if you are truly asymptomatic you don’t need your stent in your artery and it’s the same with TAVI, you don’t need an aortic valve replacement if you are truly asymptomatic.  You just need good primary practice, good medical management of your hypertension, cholesterol, et cetera, and it’s once you develop symptoms that the true benefits are there.  So, stress testing is fabulous to tease that out.
 
54;24
Excellent.  And just a call to our watchers to add your questions to the Q&A section, and so Anonymous has also asked, is it technically more difficult to do a  TAVI if the patient has a supracoronary aortic graft?
 
54:42
Yeah.  So, patients will commonly have peripheral vascular disease, they may have _____, so whether they be supracoronary aortic grafts or even abdominal aortic grafts it’s for the vast majority of these it is reasonably straightforward to do transfemoral TAVI.  There is the ability to do transfemoral TAVI where due to significant peripheral vascular disease or other anatomical issues you cannot go through the femoral arteries and then you can go through other arteries such as subclavian, direct aortic, apical, there’s even transparotid TAVI, that’s getting a bit specialized, but in essence once we leave the femoral arteries the vast benefits of TAVI compared to surgery disappear, and that then you have to think, well, should they just have traditional sternotomy, we are talking about often comorbid patients, that’s because they have significant other issues such as peripheral vascular disease, so we may do a non-transfemoral TAVI which is a possibility, but we do have significant increased morbidity, but that is a definite possibility, it’s probably about 5% of TAVI, is done outside of transfemoral, so the vast majority of TAVI is through the femoral artery and there is no issues navigating whether they be peripheral vascular stents or abdominal aortic stents.
 
56:02:
Excellent.  Can I ask, is the increased risk for needing a pacemaker is that just at the time of insertion or is that the lifelong of the TAVI, and does it change?
 
56:18
Yeah. So, there is a risk of needing a permanent pacemaker anytime you intervene on the aortic valve, so for surgical aortic valve replacement the risk of needing a pacemaker is about 5% and that’s because the AV node sits kind of right underneath the aortic annulus.  For balloon expandable TAVI it is about 6%, and then for self-expanding TAVI with newer techniques it is probably 6 to 10%, so a little bit higher, but again for ____ TAVI that is reducing as the technique and the technology has improved, but no, the risk of the pacemaker is early, so it is in the first few days or the _____ where they develop heart block after they gone home, but it’s usually in the first few weeks and once you are past that period, which is why we watch people in the hospital, sometimes a bit longer than that day 2 discharge if they have conduction issues, no then your risk is similar to every other patient in your age group that has had aortic valve intervention.
 
57:23
Yep.  And then John Meyer has asked, would you change anticoagulation treatment for AS post TAVI from a NOAC to warfarin.
 
57:31
Yep.  That’s a fabulous question.  So, one is what therapies do we do post-TAVI.  Again, in the beginning of TAVI, we treated it like a coronary stent, so we put in everyone on dual antiplatelet therapy, aspirin and clopidogrel.  We now have done some trials recently that show aspirin is enough and so it is very much we are treating up like a surgical bioprosthetic valve.  So, patients postsurgical bioprosthetic valves would be put on aspirin, we are doing the same with TAVI now, we are just putting patients on aspirin that is really important for our frail or older patients with high bleeding risk, but then a lot of patients, as the question allude to, will have an indication for anticoagulation, usually it’s atrial fibrillation, it may be previous pulmonary embolism and so then they have an indication outside of the TAVI to be on a NOAC or warfarin and then we know if you are on a NOAC for AF then we leave you on the NOAC.  We may fiddle with the NOAC.  There was funny trial done with the Xarelto post TAVI, the results weren’t quite as good as we wanted, so most TAVI doctors if you come in on Xarelto, will put you on an alternative NOAC such as dabigatran or apixaban, but that’s just as a trial evidence, but no we won’t swap you to warfarin.  You would only be left on warfarin if you came in on warfarin and the patient was stable on warfarin.
 
59:02
Excellent.  Excellent.
 
59:03
And I suppose the other thing to remember in particular from primary practice perspective is whether it is TAVI or surgical aortic valve replacement.  Once they have a new aortic valve, mechanical surgical TAVI, that I remind my patients and all of us remind our patients about appropriate antibiotic prophylaxis before procedures, because endocarditis in any bioprosthetic valve is a disaster and so, reminding patients that they need to remind their dentists and doctors who are doing skin removal, colonoscopies, biopsies, and it’s usual antibiotic prophylaxis, nothing special, whatever their dentist or doctor normally gives.
 
59:45
That was a very good point.  I think that’s all our questions unless there is any last-minute questions.  I think we are all ____ time as well.  If you have any other burning questions, feel free to email RACGP, they will pass them onto Dion, but otherwise a big thank you to our presenter Dion for sharing his knowledge and time this evening and also thanks to our webinar partners Medtronic, and thank you to everyone for attending and hope you enjoyed the webinar.
 
60:25
Thanks Trish.
 

Other RACGP online events

Originally recorded:

8 July 2021

Aortic Stenosis (AS) is the most common type of heart valve disease. Currently AS affects approximately 2% of patients over the age of 65 years, increasing to 10% of patients aged 80+. If left untreated, patients with symptomatic AS have a greatly reduced life expectancy and quality of life. Survival rates at 2 years can be as low as 50%. Early diagnosis and referral is key to patients receiving appropriate treatment with General Practitioners playing a vital role in this process.

This webinar will outline diagnostic options in general practice for identifying Aortic Stenosis, highlight the importance of early referral and discuss the evolution of both pharmacological and procedural interventions for the treatment and management of patients with Aortic Stenosis.
 
This event attracts 2 CPD points

This event attracts 2 CPD points

This event is part of Medtronic 12 part webinar series. Events in this series are:

Facilitator

Dr Trish Kahawita

Trish is a new GP fellow who is passionate about digital health, medical education, and doctor wellbeing. She has been practicing medicine for the last ten years and has worked all around Australia, in both urban and remote areas. Her main clinical interests include Women's and Children's Health, Mental Health, Neurology, Geriatrics / Palliative Care, and Tropical Medicine. She has just moved to Sydney where she will work as a medical educator for GP Synergy as well as being a community Palliative Care GP. She also volunteers as a peer support facilitator for junior doctors. She is excited about the future of primary care and the use of innovative health technologies.

Presenter

Associate Professor Dion Stub
Interventional Cardiologist

Associate Professor Dion Stub is an Interventional Cardiologist specialising in coronary and structural heart intervention. He also has a particular interest in treating the cardiac emergencies of myocardial infarction and cardiac arrest, and was awarded his PhD in 2013 developing Australia’s first treatment pathway for patients with refractory cardiac arrest, through combined research at the Baker IDI Heart and Diabetes Institute and The Alfred Hospital. Dion spent 2 years overseas in USA and Canada, as a post doctorate fellow and working with Prof John Webb, an international expert at transcatheter aortic valve replacement. Dion has published extensively and delivered multiple presentations in both cardiac emergencies and structural heart intervention, and has been internationally recognized for his research. He is a staff specialist at Alfred Hospital and Western Health and has rooms at Cabrini Hospital Malvern. Dion is married with 3 children, a keen sportsman and a passionate Carlton supporter.

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