Mayo Clinic Healthcare London Grand Rounds: Management of Left Main Coronary Artery Disease

Left main coronary artery (LMCA) disease can have life-threatening consequences for adults of all ages. Management decisions can play a significant role in providing the best long-term benefit for patients, while mitigating the risks related to revascularization. Our experts from Mayo Clinic Healthcare in London, discuss a pragmatic approach for shared decision-making for patients with LMCA disease. Featuring specialists Gurpreet Sandhu, M.D. and Malgorzata Wamil, M.D.

Grand Rounds: Management of Left Main Coronary Artery Disease

Nicole M. Eichenberger: All right. I'm going to begin. Welcome. On behalf of the Mayo Clinic School of Continuous Professional Development, I'd like to welcome you to the first Mayo Clinic Healthcare London Grand Rounds featuring management of left main coronary artery disease. Next slide, please. This webinar is accredited by the AMA for one credit hour. Next slide. Relevant disclosure for today's discussion is listed here. Next slide. A few housekeeping items before we get started today, this webinar is being recorded and will be saved to the course page. To access the recording, go to see And I will place this link in the chat as well so you can access that.

If you'd like to claim an AMA credit after the webinar, you'll be able to do so through a link that will be sent via e-mail. Next slide. The second item is how we’ll facilitate questions. You'll see at the bottom of your screen the chat and Q&A function. If you have any questions for today's presenters, please drop them into the Q&A channel rather than the chat box. This will help to ensure that the panel can see your questions. There's also a helpful upvote button, so be sure to upvote the questions you would like to see answered. If you are experiencing any technical issues during this webinar, please use the chat feature to share so our support team can assist. Next slide.

Today's learning objectives. Identify contemporary guidelines based management of left main disease. Provide individualized treatment based upon risk and co-morbidities. Next slide. With that, I would like to introduce and turn things over to Richard Pisarski.

Richard Pisarski, Commercial Director, Mayo Clinic Healthcare London: Hi, all and welcome. Welcome to our next Grand Rounds session. I’m Richard Pisarski from Mayo Clinic Healthcare in London and it's my great pleasure to introduce Dr. Navtej Buttar, who's our Medical Director for Europe, the UK, including Mayo Clinic Healthcare here in London.

Navtej Buttar, M.D., Medical Director, Mayo Clinic Healthcare in UK and Europe: All right. Thank you, Richard. Colleagues, welcome to the Mayo Clinic Healthcare's monthly Medical Grand Rounds. Today's topic is the management of left main coronary artery disease. We at Mayo Clinic Healthcare are located in the Harley Street Medical Area in central London. We are a multi-specialty outpatient diagnostic center that is part of Mayo Clinic, which has been consistently ranked number one in the world. Our great team of specialists at 15 Portland Place are well-connected with 4,000 of our sub-specialists in US. Today's first speaker, if he can go to the next slide, will be, next slide, Dr. Gosia Wamil, whose focus is on the area of cardio-metabolic disorders. And she has a particular interest in novel and advanced cardiac imaging. Our second speaker is Professor Gori Sandhu, who is the Vice Chair of international cardiology. He's managed that interventional cardiology practice here in Rochester for more than eight years. Next slide.

And Nicole, if you want to introduce our next section will be June the 8th. Actually, I'm one of the speakers, Nicole, go ahead.

Nicole M. Eichenberger: Yes. So our next Grand Rounds session will be Tuesday, June 28, and that will be with Dr. Buttar and Dr. East, and that will be 6:30 to 7:30 British Standard Time, and that's 12:30 to 1:30 Central Standard Time. And to register, you can visit the same link that will have the recording for today's session. Everything is available at So if you're interested, please go ahead and register. We do have registration open for that session.

Navtej Buttar, M.D.: Thank you. Dr. Wamil. Presenter mode. Thank you.

Gosia Wamil, M.D., Senior Associate Consultant, Cardiology, Mayo Clinic Healthcare London: It's a great pleasure to start at the Grand Rounds with my talk. I am a non-interventional cardiologists. And I would like to focus my talk on the role of non-interventional cardiologists in the management of coronary artery disease and especially in the management of left mainstem disease. I have no disclosures.

So for many years we have been told about the need for using so-called cardiovascular risk scores when managing patients and assessing the risk of future heart attacks and overall cardiovascular risk. So those risks scores have been developed based on a large databases. There are many of those options. So in the UK, we are most familiar with the use of so-called QRISK version 2, version 3. There is also added very famous example in the UK or the so-called heart age, which you may recognize on that image. However, back in an evidence base to an era of medicine. So we should ask ourselves a question about evidence-based approach and whether those risk scores that we apply to and we will use in our populations whether they have ever been shown to have a significant impact on, on cardiovascular rates on clinical outcomes. So in a large, a meta-analysis and the systematic review, it has been shown that the use of cardiovascular risk scores actually did not translate into a significant reduction of cardiovascular events.

There is also another caveat to that. And as I explained, those risks scores are statistical methods that are applied to the predictive models that are applied to different databases and different study populations. And therefore, we should not use risk scores when we are dealing with patients who may have been underrepresented in those databases. So in particular, this will involve women and also minorities or ethnic minority groups.

And lastly, and probably most importantly, in the context of coronary artery disease and future risk of heart attacks, the risks scores, those algorithms that are based on statistical methods and such, and have biases. They are based on assumptions that have been shown to be heavily influenced by the age. So the higher the age of the patient, the higher the risk score. But this does not necessarily mean that it's translated into a significantly higher risk of heart attacks and cardiovascular disease.

So with all of this in mind, in 2019, European Society of Cardiology, but also similar societies around the world, started introducing another way of screening patients for the presence of coronary artery disease. So in European Society of Cardiology guidelines, they have been through discussions and an introduction first time in 2019 of so-called cardiovascular imaging different modalities as a screening method for the presence of coronary artery disease. So they introduced CT coronary angiography as the first line and stress imaging, so-called functional imaging, as the second line. And this is all before the patient would be considered for invasive coronary angiography in the cath lab. So those are the, this is the summary of recommendations of the European Society of Cardiology when they released the use of CT coronary angiography as a cost-efficient way of assessing patients with unstable, so chest pain or asymptomatic or with atypical chest pain, not necessarily asymptomatic patients and we'll come back to that for the presence of coronary artery disease.

They also suggest that the use of functional images, and there are several of those. Those would include stress echocardiography or dobutamine stress echo and perfusion cardiac MRI, and also the use of an extension to their CTCA, a so-called CTFFR functional assessment. And those tests should be considered if there is an abnormal result of the CTCA, or there is a significant obstruction of coronary artery based on the CTCA images or if there is an uncertainty about the results based on CTCA.

So let's focus a little bit more on the role of CT coronary angiography. You may all remember that the first CT scan that had been introduced in the management or assessment of screening of patients for the presence of coronary artery disease was calcium score. So we now have a years of experience with using that technique. And you can see on your, on your right side an image that shows you how we quantify the presence of calcium. We provide a so-called Agatston score that then is applied to the populational database, and we can assess a personal risk against the populational risk of coronary artery disease.

So the idea of using calcium score is illustrated below on that figure, which shows the progression, the natural progression of atherosclerosis and how this could correspond to the calcium score and how it increases a mortality risk with cardiovascular disease. So you can see that initially and patients will have, so there was an accumulation of macrophages and foam cells in the wall of their coronary artery. This then eventually leads to a building a core of extra cellular lipids. And this is when the calcium score is still 0. There may be a presence of a very small soft, not low attenuation clock at that stage. Then the progression then leads to a building of fibrous thickening cap and the calcium, which usually indicates that the block becomes more stable. And eventually when the calcium score is very high above hundreds of Agatston score, then we can usually identify not only the fibrous core and calcium, but also that there are features of more complicated lesions.

So I would like to show you an example that I hope that will convince you that in the current stage of advancement in the CTCA and in the management of patients with coronary artery disease, the use of calcium score is not enough. So this as a 67-year-old lady who presented with atypical chest pain. Her past medical history significant for high blood pressure. She had a TIA from which she recovered fully. She also had recently a normal exercise tolerance test. Her calcium score showed a Agatston score of 62. So not dramatically high. There was a decision made at that time that despite all of that, they, the cardiologist who run the study, decided to proceed to second stage to the CT coronary angiography. And as you can see on the panel A, B, and C, so this is, this shows significant obstructive disease in the LAD, there was also disease in the first diagonal. Panel D shows you how we reconstruct and analyze the significance of that is obstructive coronary artery disease in LAD. And I just want to convince you that we are not far from the gold standard investigations from invasive coronary angiography. And on a panel E you can see, in fact, that angiography, a confirmed and non-calcified, softer plaque described on CT and it was in the mid-LED.

So the plaque wasn't, it was soft. It was a low attenuation block. So having, such blocks have more features of a, more a block that has a higher risk of rupturing.

So another confirmation and an argument for why CTCA has become now the first line and a management option for patients assessed for the presence of coronary artery disease is a trial, so-called SCOT-HEART trial from Edinburgh from a few years back. So this was a randomized control trial that recruited approximately 4,000 patients. Patients were recruited with stable chest pain, sometimes with atypical chest pain. They were then randomized to two arms, standard care and plus coronary CT/coronary angiography or standard care only. And the primary endpoint in that trial was death from coronary artery disease and non-fatal MI. And as you can see, in the trial, there was a significant reduction of primary endpoints, so of death from coronary artery disease and MIs in the group that was assessed on top of the standard curve with additional CT coronary angiography.

There are also some other interesting observations from the trial. So we now know that patients with stable chest pain, should be evaluated for the presence of CT coronary angiography depends on their overall risk, cardiovascular risk, with different imaging modalities. And CT coronary angiography should be taken into account. And it's interestingly on that trial has also showed that, shown that in patients who had nonsignificant, not classical chest pain, the CT coronary angiography demonstrated in half of those patients a normal coronary arteries, but half of those patients with atypical chest pain, not classically having features of angina had obstructive or non-obstructive coronary artery disease.

I mentioned low attenuation blocks or so-called soft block, as we frequently talk about in the CTCA field. So those are high-risk blocks. So when we analyzed the plaque in the coronary arteries with histology, we characterize those blocks as so different and so complexity of those blocks. So they had a high-risk blocks, the blocks that are more of the risk of rupturing and causing ST elevation myocardial infarction are those blocks that will have signs of inflammation, micro calcifications, fibrous cap, and a large lipid-rich necrotic core. As you can see on your right panel, so those are the cross sectional CT coronary angiography images that we can obtain by reconstructing and analyzing the lumens of their coronary arteries. And you can see we can visualize the complexity of those blocks.

So another analysis, very interesting analysis, that came from the same group in Edinburgh, and based on the Scottish data of the HEART-SCOT trial, have shown that in patients with low attenuation block, when the burden of those block, soft block, is above 4%, then they were five times more likely to suffer fatal and nonfatal myocardial infarction. On the other hand, they have shown that calcific blocks, those blocks that would be detected by the calcium score, had been in general considered to be stable. And in this trial they had been shown that they were less likely to cause rupture and cause myocardial infarction.

So the CT field and especially CT coronary angiography field is an area of fast advancement. And the novel techniques and technologies allow us to identify the block that is more likely to rupture. Those are two examples of a scan, pre- and post-heart attack in a patient. We’re using an AI technology with an algorithm that identifies inflammation in the fats surrounding the coronary arteries so we can see a significant difference. So this is a product that has been developed at the University of Oxford and has been now taken forward by a company called Caristo. So they calculate so-called fat attenuation index, which allows us then to identify fats around that coronary artery that is most likely suggested that there is a significantly increased risk of a rupture, there is unstable plaque.

So the guidelines also suggest use of stress imaging. So as an example, so this is an 80-year-old patient who had a pre-test probability, so-called, so cardiovascular risk score of 37 percent. So this was a significant increased cardiovascular risk. So the patients underwent a CT coronary angiography, which as you can see here, shows not only left main stem disease, but also a block that so extended towards proximal LAD. And in panel B, you see an example of so-called CT FFR. So this is another new technology that has been and is in healthcare, in a clinical practice, for several years now. We're getting more and more experience with the use of that technique. What it does, it applies an algorithm, a mathematical algorithm, an AI technology, in the analysis of the CT coronary angiography and provides information, functional informations, about the significance of the obstructive disease. So here are the CT FFR score was 0.98, which is nonsignificant. So the gold standard or another technique that we use to assess the severity or significance of obstructive coronary artery disease is a stress perfusion cardiac MRI. And on the panel, you can see examples of those images. And in this case, there was no evidence of profusion defects, neither at rest nor at stress. So this was not significant obstructive disease.

So talking about the stress perfusion MRI, so stress profusion MRI has been also in our clinical practice for many years now. So we use this as a functional, non-invasive method of assessing for that hemodynamically significant coronary artery disease. It provides additional information about the function of the left and right ventricle, which is always of benefits when making decisions about a type of revascularization or whether revascularization should be considered. And it also enables detection of myocardial ischemia. So it talks about viability of the myocardium. So it is able to compare the area of scarring in the left ventricle and assess whether there is a significant inducible ischemia that would suggest that revascularization should be considered. As you can see in this example, so there are two examples, on the left side you've got a nonsignificant LAD disease. And on the right side you've got a significant obstruction. So both patients had been assessed invasively during that invasive coronary with FFR. So similar technique but in the cath lab where the wires inserted during the procedure. And as you can see, so that in basic FFR assessment was negative in the non-invasive, non-significant case here on the left side but positive on the other side. And the same was confirmed during stress perfusion cardiac MRI with a significant induce ischemia in the septum and extending towards the anterior wall in the image on the right side.

I also need to highlight another very important randomized-controlled trial that has been completed a few years ago and has had a significant impact on our clinical practice, both from the interventional cardiologists’ point of view but also for us cardiac imagers. So this is an ischemia trial, so-called international study that compared effectiveness of invasive approach with revascularization versus optimal medical therapy. So for more than 5,000 patients had been recruited to have with stable coronary artery disease. The trial, the primary outcome and endpoint in the trial was cardiovascular death, heart attack, hospitalization for unstable angina for heart failure and cardiac arrest. And the patients were followed up for a median follow-up of 3.3 years. The trial was negative with regards to the primary endpoint and with regards to invasive approach. So it did not show that an invasive approach with revascularization in those patients recruited in the trial reduced their primary end outcomes.

From that cardiac imaging point of view, the importance of that trial is associated with the fact that again it confirmed and supported the role of CT coronary angiography as the first line test in evaluation of patients for the possibility of coronary artery disease. So patients that were recruited in that trial, where all offered CT coronary angiography and six percent were found to have a significant left mainstem disease without any significant unstable angina or pain that would suggest that. So we know now that we learned from the trial that CTCA is an excellent imaging modality that can exclude a significant left mainstem disease, proximal coronary artery disease. Something also that was observed in the trial and was extremely interesting that will have in future even more important in clinical outcome is that 20 percent of participants recruited in the trial who had stenosis in their CT coronary angiography greater than 50 percent, they had moderate to severe perfusion abnormality. So although the stenosis was described by the CT coronary angiography as not severe, not significant obstructive coronary artery disease, that actually, the stress imaging that in the majority of those patients had a stress profusion MRI, they, they had significant results and confirming that there was inducible schema in those regions. And lastly, that trial also confirmed and highlighted the role of myocardial perfusion imaging, so stress MRI and the role of the MRI, especially in assessing a patient and obtaining the full picture before decisions about revascularization. So I mentioned to you earlier that during cardiac MRI profusion stance we can fully assess for left ventricle systolic impairment. We can assess the presence of significant valvular pathology. So it gives a wider understanding of their clinical picture.

And lastly, I would like to focus your attention on the role of heart team. And this is also to explain why, me, and non-interventional cardiologists is involved in making decisions about revascularization in patients with coronary artery disease. So historically and initially, heart team approach has been introduced in the context of randomized control trials. So patients who were recruited to those randomized controlled trials had to be assessed by a team that's allowed a balanced view, and assured that committee running the trial, that they have taken the right decision and they there was no bias in terms of recruiting patients who, for example, had a lower predictive risk of heart attacks to a specific arm in the trial. However, over the last few years, that approach has been accepted widely in the clinical practice. So this is a heart team. We define a multi-disciplinary team that includes cardiologists with an expertise in interventional cardiology, those that have an expertise in cardiac imaging, those that have a more kind of general cardiology expertise as well. Apart from that, obviously, a surgeon, cardiothoracic surgeons, would be involved in those discussions. So this allows us to provide a very balanced approach to decision making. This is extremely important in those cases when we're dealing with complex coronary artery disease with co-morbid condition, so patients who have multiple comorbidities, which can have a significant impact on the success of a specific revascularization strategy. It also allows us to take into account a patient's clinical social situation, that, again, will have a significant impact on a clinical outcome.

So very briefly in my last slide, I just wanted to show a very quick example that shows the complexity of that approach. I know that perhaps Sandhu we'll be discussing this further, so I'm going to pause here. So thank you very much for listening, too.


Navtej Buttar, M.D.: Thank you, Dr. Wamil, for very informative talk. There are a few questions coming up on the QA channel. Let's go ahead with Dr. Sandhu’s talk. And then meanwhile, if you could please answer them online and towards the end, we will address the rest of the questions as a group. Dr. Sandhu.

Gurpreet Sandhu, M.D., Ph.D., Vice Chair, International Cardiology: Sure. Thank you, Dr. Buttar and Dr. Wamil. It's an absolute pleasure to join all of you here today. And while I get my slides setup on here, I'd like to thank all the participants for joining us from around the world. And basically Dr. Wamil had mentioned the heart team. So, Mayo actually has a very seamless heart team, that extends all the way from our centers, covering Abu Dhabi and the Emirates to London to our major destination medical centers in the US. We have approximately, I would say 300 cardiologists and surgeons who are part of our heart team. So, it's pretty much a seamless experience. If you see a Dr. Wamil, you can get a second opinion from virtually anywhere in the world, from any expert, literally within 24 hours. So, with that, I'll start my presentation here. And I love carrying on from where Dr. Wamil ended her discussion. I have no disclosures. And let's start with a clinical case. This is a 93 year old female we saw a couple of years ago. No real medical problem, just mild hypertension, hyperlipidemia, she drives her own car independently, came in with new onset of chest pain. Mildly abnormal troponins. And as you can see on the left side, she has a critical left main stenosis, it's about 95% occlusion. On the right side you see the right coronary artery and down below and the posterior descending we have at least a 70, 80 percent, blockage out there as well. So realistically you have left main disease, three vessel disease. And by default, the preferred approach would be, coronary artery bypass grafting. But how many people would realistically say 93 year old, even though she is in great shape, let's take her to the OR and have her undergo open heart surgery. So that leads to the question of what do we do next? And our team approach is definitely critical in this case. So with a ninety three-year-old, obviously surgery, even though it as an option, not really your first-line choice. What if I were to say that this is not a 93 year old. This is actually a 53 year old female. Does that change your thought process? Would someone want to put bypass grafts in a 53 year old? Or if this is someone who is 73, does that make it more appropriate at that time? So, let's look at some of the data. So, Dr. Wamil had talked about some of the discrepancies in the order studies in terms of just diversity, the patient population. So, all the surgical data came from the early 1970's. And this was basically surgery versus medical management. There were no stents in those days. So, the VA study barely had a 1,000 patients. It did show increased survival with left main disease. With ECASS, again about 700 patients, almost all males, young males below 65 which is rare to see nowadays. But these had improvement with the three vessel disease, proximal LAD and left main symmetry. With CASS trial again, 700-800 patients, almost all young males, and some nonsignificant trend towards improved survival with three vessel disease and low ejection fraction. So, this is basically where surgery versus medical management started. How about more recent data? And even their recent data is now getting 15 years old. What about stents versus CABG? Our initial good studies where the Syntax study, this had about 2,000 patients left main disease and three vessel disease patients and it was PCI versus CABG. And here what was shown was that five-year adverse events were about the same. The different thoughts were if someone had highly complex blockages, multiple blockages and CABG was better. But if someone have simpler blockages, less calcification then PCI was probably a little bit better. And then we had the Freedom trial, which once again documented that cabbage is better for patients who have diabetes, they seem to do better over the long term with full arterial revascularization. Now moving on to left main disease. When is PCI appropriate? When is CABG appropriate? So, the Syntax study basically had patients, or rather the Excel study had patients with a low syntax score. So low to moderate complexity, left brain disease, so not something that was heavily calcified, severe discipline vessel disease. And these were randomized between standard placement and surgery. At the chart below actually is pretty straightforward. And the blue line, what you see is that stroke or MI. And here what we see is with CABG, you had more adverse events in the perioperative period. But over the longer term, over five years, patients do quite well. With stent placement in red. Initial adverse events, that's strokes were lower. But over time because of increased need for revascularization, re-stenting, the numbers look a little worse. So overall this was a wash. And so, what do we do with this data? How do we operationalize it? What is a pragmatic approach? What does Mayo Clinic do on a day-to-day basis? So, with optimal medical management there is no longer a controversy of medical management versus surgery or medical management versus stents. It is simply medical management is needed for every single patient irrespective of whether they have stents or surgery or no procedure. So, this is a given. And let's take a look at outcomes. With CABG we know for a fact if somebody has arterial revascularization with the Lima graft, they will do really well pretty much forever. The graft failure rates are 5% or less. And so nowadays there is more of a preference for full arterial revascularization, with the Lima and a Lima radial artery graft. With vein graphs historically, about 20 percent will fail within a year. The numbers are slightly more nowadays. But over ten years about half the vein graphs have significant disease or have shut down. And then how about stents? With stents are current generation stents are actually quite good. With the DES restenosis realistically 3-4 percent, so less than 5%. And then earlier on, about 10, 15 years ago, there was a huge concern about stent thrombosis. That pretty much has gone away. Our current rates of stent thrombosis are realistically less than 0.5%. It's about 0.3-0.4%. And many of these are due to either some mechanical complication during the procedure or due to the patient not being able to take dual anti-platelet therapy because of some other GI bleed, some other issues. So overall, in terms of a procedural perspective, stents and surgery are both excellent choices in the right patient. So, with this, the guidelines that the US actually changed last year in December. And so, the current guidelines state that for left main disease, surgical revascularization is indicated to improve survival. However, percutaneous revascularization or stents are also reasonable to improve survival in patients with low to medium complexity of coronary artery disease. So, coming back to our patient, 93-year-old, what do we do with her? Stents versus surgery versus just medical management? So, we know for a fact as patients get older, their predicted mortality goes up higher with surgery. So, if you're in your 90’s your mortality is about two or three times higher. But if you look at SDS score or Euroscore, and with revascularization in elderly, the bottom line is they get the same success, same benefits as a younger patient. But there are procedural risks we need to consider. So, differences in short and long-term mortality. If someone is 93, they have other comorbidities. You're not going to give them a 20-year benefit of CABG. So maybe we offer them stent placement, give them good quality of life. Similarly, procedural stroke and cognitive impairment is real. So many elderly patients may actually have cognitive impairment that can last for weeks or months after surgery and they may never fully recover from surgery even though they don't technically have a stroke. So, quality of life becomes important. And then finally, bleeding is a real risk. If you put an 85, 90 year old on aspirin and clopidogrel or ticagrelor and they have a major GI bleed, then stents obviously wasn't the right thing and shouldn’t have been done. So, with this, let's go to what we see on a day-to-day basis. This is a patient that showed up a few months ago, basically middle of the night and did a ST elevation. And you look at the angiogram on the left side, there is thrombus in the left main coronary duct. So, at three in the morning or two in the morning, someone showed up like this. Simple, straightforward lesion. We simply put in a stent and the left main coronary, as you can see on the right side. Beautiful result. And the patient actually went home in 48 hours with a normal ejection fraction without requiring surgery. So, some of these decisions are straightforward. But when do you need the hard things? So, the hard things technically are indicated whenever the optimal treatment option is unclear. So, at Mayo, what we worry about besides the coronary anatomy and the complexity are the co-morbidities. We want to make sure that our patients get absolutely the best quality care they can get. And they get the best guidance that will give them the most sensible solution and the best long-term outcomes. So, here if you look at the list with diabetes, yes, surgery is still potentially better, especially with full (unclear) with systolic dysfunction, with reduced ejection fraction surgery is potentially better. But if somebody truly has an EF of 10 or 20 percent, they are very high risk for surgery, so there stents is usually a better option. Coagulopathy and bleeding risk needs to be made both in terms of postoperative bleeding as well as with bleeding with anti-platelet agents. Valvular heart disease. If somebody has multi valve disease, they are younger, otherwise viable, then definitely surgery would address both. If someone is elderly has severe aortic stenosis, then maybe TAVI or TAVR plus stent would be the right decision there. Over the last few years, frailty is another issue that has become very significant, that is always considered. So, with frailty, we need to make sure that our patients can actually not only go through surgery safely but can also undergo cardiac rehab and have good quality of life. If someone is too frail to recover, then it makes more sense to then think about medical management or stents for revascularization. Other things we worry about re malignancy. Does someone really have enough longevity to be able to get benefit from open heart surgery or should we simply put in a stent to improve their quality of life. Similarly with end stage renal disease or close to end stage renal disease. Whether someone has surgery and gets placed on a bypass pump, or has PCI with high contrast mode, the risk of renal failure is high in either case. And so, therefore, before proceeding you need to have a discussion with nephrology and the patient regarding the risk of leading life from dialysis. Other things. I won't go down every single list detail, but immuno suppression and wound healing is a concern. Liver disease, cirrhosis with wound healing is also a concern. Prior stroke impacts both CV, both stents versus CABG, porcelain aorta. I would obviously be a barrier for surgery. Someone has aortic aneurism there again, depending on the location, maybe surgery is a better option. So, with these complexities, when we boil things down, life expectancy, durability of graphs are we doing this to improve survival or symptoms is the primary concern. And then the bigger issues that we always look at are diabetes, renal function, ejection fraction, polymerase shadows, can they tolerate anesthesia, and previous cardiac surgery. Is this surgery number 2 or 3, which increases the complexity for the surgeons and then frailty. Recovery and rehab I’ve obviously mentioned. So, the current guidelines when they talk about improvement or improve survival and heart disease. With left main disease CABG is recommended. And class 2a, PCI, it is reasonable to improve survival. For diabetes, it is still pretty much the same. CABG, Lima to the LAD is preferred. Class 2a if someone is not truly a surgical candidate than PCI obviously a good option. And then finally with left main stenosis, low complexity disease, PCI may be considered as an alternative. And so, I will basically end with this last case. This is a patient who had a stress test, had ST segment elevation during the stress test, came in for angiography. Critical left main disease on the left side. On the right side you can see it as highly complex. Right coronary artery again, had severe disease. Patient was 76, no other major medical issues. So, someone like this would be a good surgical candidate. They have full outdated revascularization, and they will do pretty much well forever. And so, take home points are with stents versus surgery, we do need to individualize this. Heart team approach, obviously it's critical. Look at the age of the patient, the durability of graphs, what is the life expectancy, current and expected quality of life, co-morbidities. And then have a good patient family discussion. And any patient family discussion .it is critically important that we set realistic expectations. So they know what they're getting into, what outcomes to expect. So, I think I will stop at this point and thank you so much for joining us today.

Navtej Buttar, M.D.: Thank you Dr. Sandhu and thank you Dr. Wamil for the informative talks and also Dr. Wamil for answering the questions. Dr. Sandhu there is a question for you. You have apples and oranges and regarding the CABG PCI slide, the question is that it didn't show how many re PCIS were needed and the crossover. And yet there's a probability at five years, a one hundred 9, 6 year of SV equal to VJ. What does that track record of ten year with PCI and how many needs to be done in that time span?

Gurpreet Sandhu, M.D., Ph.D.: So great question. There are very few studies that actually show a track record of anything for either PCI or CABG. Majority of studies end at three years or five years. And realistically in the current day and age, there is one single solution. If you have simple lesions you put in stents, it obviously does not prevent new blockages from forming upstream or downstream. And that's where general cardiology, preventive cardiology is critically important and medical management for reducing the risk of recurrence and needing additional procedures. Similarly with surgery, there is no such thing as a one-time open-heart surgery. Invariably patients will come back whether it is five years down the road tens years down the road, requiring either a PCI in their vein graft, or they might form a main or distal LED blockage beyond a perfectly clean looking LIMA and needing revascularization. So, in terms of prediction and actual numbers, I think there are many smaller studies that we can quote. But realistically, things are at the point where individualization makes the most sense, both for immediate risk, long-term benefit, and hopefully over time we'll have more data. But currently I think there is really no right or wrong decision as long as you have input from both the patient's primary cardiologist, an interventional cardiologist, and a surgeon. So, there's no bias and no tendency for just one person to give their personal opinion. I hope that sort of answers the question. Thank you.

Navtej Buttar, M.D.: Gosia, Dr. Sandhu if I am a patient, how do you want to start? Should it be started with, of course, a visit with patients, primary cardiologists. But from there, if the options need to be discussed, do they first meet with interventional cardiologist and then surgeon or are there possibility of joint multi-disciplinary team like the oncologists deal with this situation.

Gurpreet Sandhu, M.D., Ph.D.: That’s also a great question. Maybe Dr. Wamil can start, and I can add to that.

Navtej Buttar, M.D.: What is your approach Dr. Wamil?

Gosia Wamil, M.D.: So, it very much depends on the clinical situation. So, in the case where you know that there is a confirmed coronary artery disease, then obviously you want your patients to see interventional cardiologist as quickly as possible. Because those of my colleagues will be able to guide the patient and describe, so what are the options, so what are the risks associated with certain, certain treatments? However, if we're talking about a patient who is not known and has never had a confirmed coronary artery disease, then, as the clinical guidelines suggest, and the data from the randomized controlled trials, those ones that I cited suggest. So, cardiologists should see the patient and assess it should be the cardiac imager that is able to offer a more noninvasive approach. Whether one of them of the imaging modalities that we've got an offer. And this has been shown to be more cost effective, cost-efficient way of assessing patients with chest pains or those who do not have chest pain but have significantly increased cardiovascular risk. So, I think that would be my suggestion. I don't know what about Guri feels about this is.

Gurpreet Sandhu, M.D., Ph.D.: This is a great question and now this varies a lot from institution to institution, especially upon availability of resources and the physicians and surgeons. So, at Mayo Clinic, we have a very unique approach. Anyone who sees Dr. Wamil or one of her colleagues across our entire enterprise, whether it is in the US or London or in Abu Dhabi. Once they see a patient, they do a risk assessment. Patient comes to the cath lab and we have cath labs as you know, in seven different major hospitals around the world. And so in the cath lab, we have diagnostic cardiologists who don't do interventions, they do the diagnostic imaging. We also have interventional cardiologists who do the diagnostic imaging. So our policy is the minute we have the pictures I will pick up a phone, I will call Dr. Wamil and say, Dr. Wamil this is what we see. And she has a capability of pulling up the images that we have here real-time, taking a look, and then we make a decision. It's a shared decision-making. And the decision there is something that needs to be treated, is this something that is safe and sensible to treat at this time. If yes, and the patient has already been consented ahead of time, we will go ahead and do the procedure. So it's a one-time deal for the patient. We don't put them through multiple procedures. If on the other hand, between the interventional cardiologists or the diagnostic cardiologist and Dr. Wamil, we feel that things are more complex and needs more discussion we simply stop at and we then have the patient meet with a surgeon. Or if it is something that is too critical or too high risk and the patient cannot be sent home, then we will simply call the surgeon. They would walk down to the cath lab and we literally have a three-way consultation right there and then make a decision at that point we take the patient off the table, let their sedation wear off, and then have a proper discussion with the patient and the patient's family about risks of surgery versus high risk stents. And so it's a nice heart team approach, but this is a heart team in real life as opposed to simply on paper.

Navtej Buttar, M.D.: Thank you, Dr. Wamil, and thank you Dr. Sandhu. Any other questions from colleagues participating in the grand rounds? I found one other question. Pardon my ignorance. The radiation exposure with the imaging technologies that you are informing versus MR. What's your view on that? Do you take some pre-test probability to use one approach versus other approach if there's concern with the radiation exposure?

Gosia Wamil, M.D.: Well, yes. So, we are very lucky here at the MCH in London because we've got a service that provides so all sorts of imaging modality. So, I can assess a patient and choose the right modality that will give me the highest benefit. The more certainty about the significance of coronary artery disease or any other differential diagnosis. And also, this is balanced carefully against the risks of different modalities and use of different imaging modalities such as especially radiation. So, we're very, very proud of the advancements in CT coronary angiography. And so, in the past, we used to be criticized for using a quite high doses of radiation. And then the main criticism used to be that the international colleagues would come back to us and say, well, if you've used such a high radiation dose, and you've just acquired diagnostic images is this really helpful? I still need to take the patients to the cath lab. So, this is not an argument any longer. So, these days with modern scanners and it's still very much depends on the on the type of the scanner that is used for the CT coronary angiography. But with the modern scanners, we can reduce the dose of radiation to the dose that is comparable to a few chest x-rays. So, we are winning on that front. And CT coronary angiography is advancing. There are those new techniques that I have shown. So, examples of those. So, CT FFR, the Karystos company, proposing that AI use of algorithms that define how severe the plaque is, what is the risk of the rupture of the plaque. So with all those images, and with all those advancements, so we believe that we are providing such a valuable additional information that there is a huge value of using CT coronary angiography before we send patients to interventional colleagues and these days mostly to ask them to perform angioplasty. So, um, in the, in Europe, I think we've been observing over the last few years and advent of using cardiac imaging, CT coronary angiography and stress imaging, I think especially cardiac MRI profusion in a non-invasive way of assessing patients with chest pain. And I'm sending to the cath lab only those that will require stent insertions. So, this significantly reduces the number of diagnostic, invasive angiographies. We all know there are complications associated with those procedures. So, we hope that's with that strategy we are creating a safer and less invasive cardiology.

Navtej Buttar, M.D.: Dr. Wamil, Dr. Sony had a question also asking for a comment on Fortego system radiation protection. Could you comment on that, please.

Gosia Wamil, M.D.: And so, the radiation protection from I don’t fully understand the question.

Navtej Buttar, M.D.: It's in the chat. Dr. Sandhu while we're looking into that what is your view on the radiation?

Gurpreet Sandhu, M.D., Ph.D.: So, radiation safety is a huge concern. And here at Mayo, including at our facility in London, we are fortunate to have a complete spectrum of capabilities. So, depending on the patient's presentation, not everyone needs a CT angiogram or a coronary angiogram. With many, you can simply do various modalities of stress testing with imaging without use of any radiation. And we don't routinely use CT angiograms as a screening, do sequential follow up too. So, things are driven mostly by symptoms. If someone comes in with symptoms, stress echo might be the best modality where you can actually assess a patient's functional capacity as well. And then also we have radiation physicists and biomedical physicians that are part of the cath lab team and our diagnostic radiology team that basically monitor radiation exposure both for the personnel and the patients. And we continually try and dial down the levels. And not only do we optimize our own machines and the cath lab to get the lowest possible radiation exposure for the patients and the personnel. We actually have values that we have set internally that are shared openly with other centers, other sites. So, if anyone is concerned about radiation protection or radiation levels, with their x-ray machines, we'd be more than happy to help work with the companies and get those down for you.

Navtej Buttar, M.D.: Thank you Dr. Sandhu. Dr. Wamil. We are at the top of hour. Sorry, that was the last question about the Protego?

Gosia Wamil, M.D.: I think the question applies more to Dr. Sandhu rather than me. This applies to radiation in the cath lab.

Gurpreet Sandhu, M.D., Ph.D.: Yeah. Yes. Also, there are many different systems that wasn't familiar with this brand name. That basically you have big shields that you get between yourself and the patient. And you can sometimes walk around with shields. In general, it's a good concept, but from a practical perspective, it’s very difficult in terms of reaching their equipment, maintaining sterility. And especially with trainees, with advanced fellows in the lab to switch position with them. It is a little bit difficult. We also actually have our own processes that we developed robotic PCAs and get our staff away from the radiation completely. But that is still pretty early stage with robotics. That's probably another 5-6 years away. But this is completely something which we are looking into and we're developing our own technology is truly radiation is a concern. And anything we can do to reduce that would be absolutely wonderful.

Navtej Buttar, M.D.: Well, thank you, Dr. Wamil, and thank you Dr. Sandhu for the incredible talks and very informative Q and A session. I would also like to thank our participants. If you have more questions. Nicole, can they still send you the questions through chat box so that we can share or is this it?

Nicole M. Eichenberger: I don't know about that. If they can still send me questions this way.

Navtej Buttar, M.D.: Sounds good. Well, thank you and have a great rest of the day.

Gurpreet Sandhu, M.D., Ph.D.: Thank you.