Many patients with CAD present with CKD and these patients have a significant increased risk of CV mortality due to CIN. At the ACC2021 Virtual Innovation Stage, Dr. Ziad Ali and Dr. Jai Radhakrishnan discussed these patients and the challenges in diagnosis and treatment of CAD alongwith a variety of tools, techniques and insight that may help facilitate less risky PCI.
Hello everyone. I hope you're enjoying A CC 2000 and 21 with exciting late breaking clinical trials and featured research sessions. Were excited to talk to you today about how we should optimize Pc I N. C K D. I'm Ziad Ali from ST Francis Hospital and Heart center and the Dramatics Cardiovascular Institute. And I'm joined by my good friend and recently former colleague J Radhakrishnan, who is a professor of medicine and neurology at Columbia University Medical Center. Over the next 25 or 30 minutes we're going to be talking to about how we should optimize PCI from both the nephrologist point of view as well as from an interventionist point of view. But most importantly, I think what you're going to note is that a synergistic collaboration between the nephrologist and the interventional cardiologist is key in managing these patients. These are relevant disclosures for doctors, Radhakrishnan and I. So the objectives of today's session are that dr Radhakrishnan will take you through the definition epidemiology and risk factors for contrast induced neuropathy and for CKD in general and patients who are undergoing invasive angiography and potentially pc I how we might be able to prevent contrast induced neuropathy or contrast. Associate acute kidney injury and to introduce you to this important topic of regionalism. A sort of surrogate of racism for patients who are in need of invasive angiography but might actually have it be avoided due to their proposed risk. Well then transfer over to me and we'll talk about how we can limit contrast induced neuropathy or contra associated acute kidney injury during angiography and PC. I and what some of the technological advances are that facilitate angiography and PC. I in advanced ckD. So gi welcome, thank you very much for doing this. And I'm absolutely delighted to have not only a nephrologist, but one of the founders of the first cardio nephrology programs in the country to advise us in this lecture. Thank you. See it. And it's indeed a pleasure to be here at the sec. So, I shall begin my talk and trying to define what is contrast induced the property. And I think the most universally accepted definition in 2021 Is the Katy go criteria where uh, if you give a patient contrast and you see a rising creatinine within 48 hours of 0.3 or a 50% increase in creating about baseline within seven days. Or if you are measuring urine volumes through a fully catheter, especially in ICU patients, you see a drop in your involvement on the 0.5 mils per kilo for our for a period of six hours after contrast would all be considered as being associated with contrast in the property. So, why does contrast of property happened? It's a complex model. But there are key to key uh, events with Chaka usually consequentially to giving contrast. So the first is that there is an intense phase of vessel constriction when uh, contrast is first administered and that is a set up then for contrast being concentrated in the proximal renal tubular where it's a direct toxin. And as these cells undergo damage and necrosis, it incites the entry of inflammatory cells including neutrophils and macrophages which further propagate the century and the consequences a drop in kidney function uh in the hours today's uh subsequent receiving contrast. So how common is this? So if you look at the G. F. R, that's the single most important predictor of who's gonna uh actually reach contrast and property. So if you look at normal G fr above 60 on the left and you proceed along mild, moderate and severe detriment in the G. F. For 230 You see the bar which is essentially the number of people requiring dialysis from .7% all the way up to 4.3%. And correspondingly the incidents of a contrast of property goes from about 5%, about 26%. And the most severely affected patients with G.F. are under 30. So what is the consequence of uh of a patient with a K. I. And our dialysis following a contrast procedure. And there are these are association studies and you can see on the left bottom its debt. So when you go from a G. F. R. Of uh no, no contrast of property 0.5. All the up to 34% of mortality in patients who need dialysis and bleeding is commoner as well as the risk of uh a post procedure. Myocardial infarction. So everyone's familiar with this calculator by dr Moran who was at Columbia of several years ago. And I'd like to point out that the two most common risk factors at the bottom is the volume of contrast and the severity of CKD before the contrast is administered and that's really the focus of this talk. Many of the uh risk factors above these two are really not modifiable but clearly if you can produce contrast volume and uh this might serve patients better in terms of this very devastating uh complication of procedures. So when you look at another registry, this is the N. C. D. R. Cat pc a registry and you look at once again what is the most important risk factor for A. K. I. On the left and Dallas is on the right. You see at the bottom it's uniformly severe, detrimental G. Fr which is the most important risk factor in this group of patients. So one uh confound er is that in patients who are receiving contrast, it just might not be the contrast alone that's causing a decline in kidney function. Because many of these patients have an acute illness which enough themselves could lead to a drop in kidney function. For example, patients may have an acute M. I with or they may be in a hemorrhagic situation or infection of ischemia. And all these factors at the bottom, low cardiac output hypertension hyperbole mia all play a big role in the incidents of a key i uh in such patients. So we'd like to if possible uh separate contrast induced A. K II versus contrast associated daycare. And many times this is not possible. And we have to basically look at these patients as a holistic manner to try to mitigate the effects of contrast on these patients. So we'll discuss some of the preventive strategies pre and geography and then most of the studies have been negative as you're well aware. But I'd like to just point out that uh the uh there have been many contrast media available and the role of low osmolarity versus Aiso a smaller uh has been debated for a long time. But I think the most recent meta analysis suggested that is a a smaller uh contrast media for example, Dixon all at the bottom may have a slightly lower risk of C. I. N. Than the low a similar group. But these are not considered to be clinically important because the p value was just borderline when comparing this uh study was his others. Okay, so the single most important point about prevention is hydration and this is the consensus um volume requirements before the procedures. It's 1 to 1.5 ml tequila per hour, 3 to 12 hours before the procedure and for 6 to 24 hours afterwards. So another interesting um method of ensuring volume and also to prevent the sludge ng of contrast within the tubules is to give the patient furosemide and then match them with hydration to exactly reproduce the urine volume required um to come versus the I. V. Saline administered. So you sure can achieve this urine volume using this procedure. So it's a it's a device that measures the collection of urine volume and then calibrates the I. V. Saline infusion to exactly measure the exactly after the urine volume after giving the patient for euros might. And indeed in in in one of the trials it showed that there was a clear reduction of events in the group that received the real guard device. And in a systematic review meta analysis. Also this device favored the prevention of contrast and property. I'm going to pause right here and ask uh Yeah I mean does he use this device in his practice? And how helpful do you think it is? Thanks guy. Well um well the original trials were a little bit difficult to conduct because they were in order to completely match the ins and outs. Um There was a trial protocol which involved fully catheterization of both um of all patients. And of course for uh today's interventional cardiology practice. Even in patients with CKD um fully categorization has its own risks hazards. And as a result it was somewhat difficult to recruit during the early parts of this study. Um Nonetheless I do think that creating a target for for any of these metrics either using a specific device or by matching hydration uh to output. They all kind of point towards the same thing and that is the critical importance of hydration. Thank you very much. So there's another interesting observation which began with pre clinical trials in lab animals is that if you induced ischemia in a remote area, for example, the arm by inflating a blood pressure cuff for five minutes and you separated by five minutes uh and give four cycles of such inflation. It prevents damage to organs in the setting of surgery as well as contrast. And the way this works is um when you when you produce ischemia an organ, there's a systemic release of certain preconditioning substances and there's a long list of these substances and what it does is that it changes energy uh kinetics especially at the level of the mitochondria. And in doing so you get effective remote organs, for example, the heart as well as the kidney in preventing damage to these organs during periods of stress, toxic toxin and ischemia. And this has been used for example, in contrast in the next slide. So when you look at patients who are in the cap lab and are getting uh just hold, just being prepared for the contrast can go to the next flight early. Yeah. So we can see that uh using this remote ischemic preconditioning, there's a sharp drop in in this in in the rates of contrasts of property in especially in patients with advanced kidney damage with G. F. R. is under 30. So the other concept from a nephrology standpoint is is the axis for the angiography. So traditionally people have been using the femoral artery but increasingly nowadays the radial artery is a favorite site because the complication rates from bleeding are much lower the big problem from our side. As nephrology says we would like to preserve the radial artery for future A. V. Fistulas. And it's been shown that there is a significant but fortunately small rate of radial artery occlusion following the procedure. And I'd like to ask ali and we've been through this a couple of times is how best do you approach such patients? Especially those patients whose G Fr. Is under 20 and who are imminently looking at dialysis over the next few months or a year or so. So how would he approach such patients? Yeah. It's an excellent question. And um one without an answer. The from the interventional cardiology community there is I would say some pretty robust evidence in meta analysis to suggest that radio artery catheterization is safer for patients predominantly from a bleeding point of view. And if you if you basically extrapolate that from all comer patients to ckD patients who are unique in that they have a high throw Bostic and ischemic risk but also have a very high bleeding risk. There is actually a considerable advantage to using the radial artery at least theoretically um where the balance lies between This 5% risk of radial artery occlusion at seven days versus the loss of access site. And they're balanced against their bleeding risk from federal access. No one really knows. And it's a rather difficult question to answer. Certainly, I think if that patients have, say, for example, a right radial artery fistula, um or they've got previously failed fistulas and you're on your last site, for example, I've got a left and it's failed or failing. Then I'll probably end up using the groin. But we really don't know here, giant. And we need some better studies to help determine this. One thing that I should say is that meticulous care to radio artery homeostasis can definitely reduce this number. And the evidence shows that we can get this to about less than 1% if we do something called patent radial homeostasis. And that basically means rather than just pulling a band as tight as you possibly clan and including the radio artery if you tighten the bend until the point that the bleeding stops. But you can still feel distal perfusion and pulse, then the Peyton sees much better. Thank you. So let's, we'll end with regionalism. And uh, how do we handle this from our site as an astrologist? Uh there are a couple of things we need to consider. So what is realism? It's the uh inappropriately low rates of coronary angiography and patients, especially with kidney function were elderly. And this is uh a seminal paper by Glenn shirt House an astrologist. And if you look at uh this study uh you look at various propensity groups and this is looking at each quintile from 1 to 5 and for each quintile compared to the reference one, you can see there's a much lower likelihood of undergoing coronary angiography appropriate for the procedure. So the appropriateness was determined by A predefined uh calculus. And you can see overall that your chance, your chance of getting an angiography in patients who are uh we're supposed to get it was 40% lower than what you expected. So this is regionalism. It's being a little nihilistic about coronary procedures. And the question is how do we approach this in a combined cardio renal fashion. So another study that looked at managing uh cory artery disease in CkD patients um And these were randomized into an invasive strategy and patients were deemed to require it versus a conservative care. And they asked the question, are you going to see a lower rate of death or a nonfatal am I and also angina related health status event. So the bottom line in this paper was that the risk of death or nonfatal? Um I was no different in the two groups invasive. Was this conservative care. And also I'd like to point out that on the left. You can see that the rate of C. V. A. Was a little higher as was also the risk of death of diocese in the group that received the invasive strategy. One problem with this study was that revascularization was profound in only one half of the patients who were destined to receive it in the invasive strategy group. So I think the jury is still a little open out there to say is it really um uh worth not pushing an angiography in patients who would need it in in in in the presence of CKD. And I think uh better studies and longer studies are required to answer this question. So here's the major conundrum is when patients are referred to me say by a cardiologist saying could you claim a patient who has to get the for a left heart study? And I would say let's talk a little bit. What is the risk stratification? There's a patient really required this or can they wait until they hit dialysis? Or is he a patient who could manage with just a conservative procedures? So this risk benefit analysis is always on our minds when we analyse situations. So what we typically do and I'm sorry this slide is a little messed up. But if you look at G. F. R. Is about 60 we would ask them to stop metformin insects and rats and bidders prior to the procedure and continue with statins or start them if they haven't done so already for patients with GF are between 30 and 59. We would do the hydration protocol as we discussed And then this is a very good time to discuss intra procedural interventions which are which is a is going to talk to you about very, very shortly. And in those patients whose Jaafar is low, especially if it's below 20, we would strongly consider hospitalizing this patient and we'll have a real service follow such patients And then very, very importantly, we need to know who is the person in the group that can use the lowest quantity of Volume 2 to perform the procedure. And then once we have made this this discussion uh and we're both comfortable the cardiologist, nephrologist and it's very important for the patient to know, hey, it's not going to be a walk in the park, there is a risk. But this procedure is very important as we have discussed before and we provide some reassurance that the kidneys service will monitor you in the hospital. And we have agreed on a plan to reduce this risk as far as possible and then especially if it's zero. And I'm going to tell the patients, look, I have a lot of confidence in ZR performing the procedure and your chance of getting kidney failure is very, very low because he doesn't use much contrast at all. And then finally, the once the patient is in the setting of an urgent left heart cath, you'll do all of the above has discussed. But the critical part is that since these patients are technically more complicated and at much higher risk of a key. I we would plan for dialysis in the right uh scenario. So to conclude contrast induced a K II. Or associated acai is common. It's associated with significant morbidity and mortality. And they're clearly uh pre and intra procedural interventions that have been shown to reduce the risk of this complication and a careful assessment of which was his benefit. And using cardiologists with specific skills to minimize contrast volume is critical to avoiding realism. Regionalism should say realism is correct. Thank you guys. So um I'm up next and I think this dovetails beautifully on what I was talking about because this really has to be a partnership between the nephrologist and the cardiologist. And to be honest not just sort of one cardiologist In our program, we have a group of cardiologists each which understand the nuances of patients with cardiovascular disease and advanced CKD. And that might mean individualized decision for patients with low ventricular functions who meet criteria for defibrillator because having someone who's on dialysis who is being accessed centrally three times a week who also has an implanted lead might not be the same risk ratio as someone who doesn't uh you know for example expertise in something like subcutaneous II. C. D. Might be very valuable in that situation similarly with pacemakers. But these are some of the things that guy and I will discuss in uh the discussion section. So with regards to invasive management there is a problem. So this is a patient of mine in december 2017. Bad coronary disease. Right so patient is in CkD Stage five. It's obviously a complex P. C. I. We gave the patient a 2% risk of need for dialysis. The patient became very scared after discussing with their nephrologist and their local cardio primary care doctor as well as cardiologist who said there's no way this can be fixed. We should be managed medically. And you see 10 months later there is rapid progression. Now the patient is presented with an acute coronary syndrome. So this is the real manifestation of regionalism in real life accelerated accelerated atherosclerosis in an extremely high risk patient population. So how do we minimize risk? Well this is both easy as well as a little bit disappointing because there are really only two proven methods to reduce the risk of invasive risk. For contrast associated cute kid injury. One is hemo dynamically guided I. V. Hydration. This is the Poseidon study published in 2014. The Lancet and you can see that the risk of major adverse events, death, myocardial infarction and dialysis is all reduced in patients who undergo a left ventricular and diastolic pressure guided hydration strategy Should be noted that the mean Jaafar in this patient population was around 50 not 20 where the extreme risk may lie. And the second was actually a study published in 2014 called the Mozart Study, which looked at using intravascular imaging to act as a surrogate for many of the things that usually require contrast injection on angiography, they showed that for straightforward PC. I you could reduce the risk of Uh reduce the use of contrast by approximately 50. So the first thing that we have to discuss is what is actually the contrast limit, how much is safe. So this is work by the brown group from Rhode island, which shows that after about a ratio A contrast volume to Egypt a ratio of one. You start to see an increase either risk adjusted or crude in the risk of you moving on to have a contrast associate acute kidney injury. We actually validated this at Columbia and found an almost identical number just slightly lower at 0.89. And that means that you need a certain volume to actually inject into the coronary artery. And we'd say in Egypt for of less than 15 would be the right amount. We typically use projections, right coronary artery, left coronary artery and then the left ventricular end diastolic pressure is used to guide hydration. So we're gonna move straight onto a case. This 71 year old male with a history of asthma hypertension. CKD with a very high creatinine. But the patient has had a stable craning has really wants to avoid going on dialysis For many reasons, including lifestyle limitation. And he would like to continue to work. The patient resorts Disney as well as chest pain and a diagnostic catheterization revealed severe multi vessel coronary artery disease. And at that time PC. I have the right coronary artery was done using 13 CCS. And the patient was planned for a stage zero contrast catheterization and pC. Of the LED answer complex. So this is an ultra low contrast angiogram and what you'll notice that's the patient moving. Typically we do not move the camera during a ultra low contrast angiography because this really has to act as the blueprint for the entire procedure. So really these should be non contrast a non panning angiograms. And so if we focus on the left side here, what you'll see is there are two lesions which are moderate to severe. Uh they would be characterized an ambiguous lesions and under most situations in most catheterization laboratories, what would happen here is the operator would go ahead and take multiple views of this three dimensional structure in two dimensions. Using contrast angiography and all of those angiograms add up very quickly. But now we have different technologies to be able to help us. The first thing we want to do is to assess whether or not those lesions are physiologically significant. Well how do you know your guide is actually engaged? Well what you'll notice is you have a flat E. K. G. On the left side and on the right side by injecting 0.9% sodium chloride into the artery. You get E. K. G. Changes because of course conveniently the myocardial conducts electricity. Once you engage the guide catheter, we do have other strategies to be able to help us. And that is to take a contrast angiogram. A single shot and use something called the dynamic coronary roadmap. The dynamic coronary road map basically creates a real time automatic motion compensated coronary image that you will move with the patients. So if you move the table or move the patient a little bit it will stick with you. And that allows you to minimize the amount of further um the injections that are required. Now here's an example of assessing legion significance. So what we've done here is advance the I. F. R. Pressure wire, the omni wire which is extremely favorable characteristics. And now what we're doing is we're doing an I. F. R. Pull back to actually co localize the site of the pressure drop where we think the angiogram was. And so we remember those approximate lesion of the angiogram and we see a focal step up in the approximate led. One thing that's very unique about sink vision is that we can actually go ahead and co register the angiogram and the uh the pressure wire without using any contrast. So by pulling back your wire and using the sink vision system, you can see that the fr wire has detected where the pressure losses confirming that the lesion that we saw on our and geographic blueprint is in fact the culprit lesion and that stenting this lesion may have some clinical and prognostic benefit. Whenever we do imaging or physiology guiding PC. I. We really want to divide things up into those things that make the most clinical impact for the patient. So pre Pc I would like to know the morphology, length and diameter of our artery. We'd like to know post PC. I whether there's a dissection which may cause a late clinical outcome that the stent is opposed in that floating and that we have maximum expansion, which is the most important predictor of long term clinical outcome. Now that's intravascular imaging. Made easy. It's a little bit more difficult when you can't use any contrast. But we do have some tools for this. So this is I've a sink vision without die. So we've activated the sink vision system and what the ST vision has done has identified the wire as the region of interest. But fortunately sink vision allows us to manually manipulate this ibis and by pulling it onto the wire, you'll now able to see that we can co register this ibis in perfect location with the lens and the marker right on top of each other allowing us to perform imaging guided Pc without the use of any contrast. And so now if we do a pullback we're able to look at the morphology within the artery. Looking at the artery from the inside out and the outside in. And the most important finding here is that there is very minimal calcification. So our lesion preparation strategy is not aggressive and we are likely going to be able to direct stent. Now the this also allows us to determine perfectly how big the artery is. So here we're measuring the diameter of the artery at the distal reference and you can see that it's measuring 3.4x3.9. So mean of 3.6 We do the same thing at the proximal edge. And so we find a normal landing zone and go ahead and measure again. Remember distantly we were 3.6. Now, approximately our measurements show that were 4.2 and you'll see on the sink vision. It's telling us that we need an 18 millimeter device. So what that really does is allow us to perform a PC. I. Strategy upfront knowing all of the equipment that we need. So we need a 3.5 by 18 millimeter stent to cover the physiological gradient identified by sink vision. We're going to direct stent because there's very little calcium and then we'll consider post dilation with a 3.5 by 12 noncompliant and even a 40 12 noncompliant. So all of our equipment is in the room. And this procedure becomes much more like a taverna or planned procedure than something that's happening at hawk. And so what we can do for placing the stent is actually use the co registration. If you remember on our initial ideas, try registration. We mark the distal reference and by marking the distal reference with the ideas we can line up our stent in exactly the same place and expand our stent. Minimizing the risk of an geographic miss and then we have excellent features available to us, such as device detection. Of course, one of the problems with imaging guided pc. I without contrast is that you need to make sure that you are where you think you are and what we don't want to do is inflate the balloons and segments that may not be stent, ID or may not be injured. But the Philips device detection allows us exactly to line up our markers within the stent. To minimize the risk of edge complications and make sure that only our stinted segment is expanded without a network effect elsewhere. And you can very quickly do assessment of the medial and proximal edge to make sure that there is no edge dissection here, you can see that at the proximal and distal edge. We're doing a quick perusal to make sure that there is no evidence of a major edge dissection and in this situation you'll see on either side that indeed there is not. We also want to make sure that our stent is not floating and that it's fully opposed. And again, a quick perusal through the artery allows us to ensure that there are no floating stents. And the stent is indeed touching the vessel wall propagating and allowing maximum vessel healing. Finally, we want to measure the expansion and by measuring expansion, we need to first measure the area at the distal reference. And here we can see it's about 7.2 millimeters squared. And then what we want to do is do the same thing and measure are minimal stent area by finding the smallest area within the longitudinal segment of the stent. So here you can see that on our longitudinal segment, our minimal stent area is gonna be somewhere in this region. And then by finding that region, we can go ahead and make a measurement. And so by making a measurement at the distal reference area as well as the minimal stent area. It allows us the opportunity to measure expansion. And in this situation we know that the distal reference there was 7.1. The minimal stent era, 7.2. So the stent is greater than 100% expanded. And then what we can do is actually do a post pc II fr without using contrast. And but because we know where our stent is already placed, we have a workhorse wire. The omni wire is extremely favorable wiring characteristics. We can simply place this distal to the stent and measure the I. F. R. And we confirm a successful procedure with not only the acceptable, but the ideal I fr target based on the defined pC. I study of greater than 0.95 and you can see the P. I. Have defined Pc. I alan Jeremiah's is here with me on this case. So this patient actually underwent a zero contrast PC. I. The patients now completely angina free the Creon and his 5.1 day one, we rechecked it at day seven. I didn't show you. But we did a physiological lesion assessment of the circum flex, which was the other lesion and it was completely negative. And as a result, we were able to provide a complete revascularization on this patient With a total of 13 mm and maintain them in the healthiest way possible. Minimizing their risk for dialysis. So, in summary in the catheterization laboratory technology can significantly impact the ability to perform complex PC. I. In this subgroup. The sink vision physiology confirmed the presence of a scheme in our case and the absence of ischemia post pc. I. Making sure that we have the optimal outcomes for the patient. The omni wire has excellent handling characteristics in my opinion, is the gold standard of physiology wires currently available. Try registration allows synchronization of angiography. I fr and ibis to limit the use of contrast in high risk patients and really genuinely allows you to look at the artery from the inside out, both from an atherosclerosis point of view but also from a physiology point of view. Finally, device detection allows accurate precise placement of devices to avoid geographic myths and avoid injury of the edges of the stent and ultra low contrast or in fact in this case zero contrast Pc. I is certainly feasible and maybe safely performed in complex patient cohorts. So thanks very much. If you were interested to learn the step by steps of zero contrast pc I you can record or click on this link where Allen and I perform a complex zero contrast bifurcation. DK crush. Thank you very much. And I look forward to the questions. Thank you very much indeed. Uh huh. So giant. Why don't we start while we get some questions how much of a problem is realism outside of major academic institutions. And then second question is how much is the public reporting of dialysis induced by procedures? A limitation or propagator of realism in your opinion? So, I think this is real. And you know, we've, you know, over the course of my career, we've had to uh get patients, you know, into our center because they were basically getting, you know, really limiting in china for example, they were pre dialysis or they were pre transplant and the message will be uniformly, you need to go on dialysis and then we'll fix the, you know, the arteries. So it's real. And uh you know, luckily we managed to take care of most of these patients within our center. I'm not sure about the reporting strategy but I do believe that a. I. Is a major um complication that needs to be reported, right? So I mean I actually think from the interventionist point of view gi that this uh journalism is massively propagated by public reporting. So new york massachusetts many states have um it is reportable if you put a patient on dialysis now, what's interesting about that is that you get the same Slap on the wrist or report that goes into the New York State PC registry, whether the patient Scranton going in is seven or whether it's 0.7. And so what happens is patients where when we are clearly assessed by metrics from the state, there is genuinely an avoidance for operators to take on the risk of a publicly reportable event If they don't have to. So what happens is the patient with the crown in a 51. They simply get medically managed and you've shared these patients with me over the years where patients are referred from outside centers after being repeatedly being told that they can't have a procedure because of the fear of dialysis. So thank you. Yeah. And uh we should uh wind up now because we're over and there are no further questions apparently. So thank you very much. I appreciate everyone's time and I will see you soon feel free to reach out to either of us if you have any questions about this interesting patient population and enjoy the rest of a. C. C. Thank you.