Part 2: Beyond the Basics
Originally broadcast Tuesday, March 2, 2021
Join Us For Part Two of our LIVE 2-Part Virtual HVAD Waveform Bootcamp
Featured Faculty
Michele Kassemos - Moderator
Michael S. Kiernan, MD, MS, MBA
Marwan F. Jumean, MD, FACC, FSCAI
Jennifer Pavone, MS, RN, AGACNP-BC
Brief Statement HeartWare™ HVAD™ System Indications For Use: The HeartWare™ HVAD™ System is indicated for hemodynamic support in patients with advanced, refractory left ventricular heart failure; either as a Bridge to Cardiac Transplantation (BTT), myocardial recovery, or as Destination Therapy (DT) in patients for whom subsequent transplantation is not planned.Contraindications: The HeartWare System is contraindicated in patients who cannot tolerate anticoagulation therapy. Warnings/Precautions: Proper usage and maintenance of the HVAD™ System is critical for the functioning of the device. Serious and life-threatening adverse events, including stroke, have been associated with use of this device. Blood pressure management may reduce the risk of stroke. Never disconnect from two power sources at the same time (batteries or power adapters) since this will stop the pump, which could lead to serious injury or death. At least one power source must be connected at all times. Always keep a spare controller and fully charged spare batteries available at all times in case of an emergency. Do not disconnect the driveline from the controller or the pump will stop. Avoid devices and conditions that may induce strong static discharges as this may cause the VAD to perform improperly or stop. Magnetic resonance imaging (MRI) could cause harm to the patient or could cause the pump to stop. The HVAD™ Pump may cause interference with automatic implantable cardioverter-defibrillators (AICDs), which may lead to inappropriate shocks, arrhythmia, and death. Chest compressions may pose a risk due to pump location and position of the outflow graft on the aorta — use clinical judgment. If chest compressions have been administered, confirm function and positioning of HVAD Pump post-CPR.Potential Complications: Implantation of a VAD is an invasive procedure requiring general anesthesia and entry into the thoracic cavity. There are numerous known risks associated with this surgical procedure and the therapy including, but not limited to, death, stroke, neurological dysfunction, device malfunction, peripheral and devicerelated thromboembolic events, bleeding, right ventricular failure, infection, hemolysis, and sepsis. Refer to the “Instructions for Use” for detailed information regarding the implant procedure, indications, contraindications, warnings, precautions, and potential adverse events prior to using this device.Caution: Federal law (USA) restricts these devices to sale by or on the order of a physician.Waveforms Disclaimer Virtual Disclaimer www.medtronic.com/us-en/privacy-statement.html
Mm. Uh huh. Mm, yeah, yeah. Mhm, Mhm, yeah, Mhm, yeah, Mhm, yeah! Mhm, Yeah, yeah! Mhm, yeah! Mhm! Mhm. Mm. Yeah, yeah, yeah, yeah, yeah! Mhm. Mhm. Mhm. Mm hmm. Mhm. Uh huh. Hello. On behalf of Medtronic NCs, it's my pleasure to welcome you to part two of our two part virtual H Bad way from boot camp. Last week's webinar had 145 attendees from 44 countries, including Australia, Canada, Taiwan and the United States. We'd like to thank you for your attendance and the tremendous positive response to receive from many of us after last week's session. There's absolutely no doubt that its success was 100% attributable to the presence and contributions of our distinguished faculty. Here with us again today is Dr Michael Kiernan, the medical director of Toughs. Bad program in Boston, Massachusetts. Doctor Marwin Julian is joining us from University of Texas Health Science Center in Houston, where he's an interventional heart failure cardiologist as well as a former fellow of Dr Kern in a Tough and Miss Jennifer Pavane, acute care nurse practitioner and the director of transplant operations at N Y u Langen Health in New York City. Welcome once again to you all, and without further ramblings, I'll kick it over to you, Dr Kernan. Great. Thanks, Michelle. So much. And thanks. As always for the invitation to speak at the electronic age Bad waveform bootcamp. Welcome to all of those who are able to join us last week as well as to those who are you who are new to the presentation this week in terms of how we're going to spend the next hour, I just want to spend a quick 5 to 6 minutes providing a brief review of what we talked about last week, and that's really discussing how wave forms are generated in reviewing the physiology of continuous flow. L VADs with the understanding that if you I feel strongly that if you understand the information provided to us in a bad way, forms and you, in fact do have a solid, uh, understanding of of continuous flow physiology and the patient with advanced heart failure and then after that, we'll dive straight into a number of cases and then, for the last 15 or 20 minutes, will spend some time looking at the other pieces of information that are available to us both on the H vac monitor as it relates to looking at historical trends of data as well as in log file analysis. As I mentioned last week, one of the primary values to me, uh, and using this device is the information that is provided to us in the wave forms as it relates to, uh their ability to impact, um, diagnosing the patient's condition into assisting with clinical management, uh, and device optimization and what that will jump back in. And so, as I mentioned, we have a few slides that are our review, for those of you were with us last week. But review is always good, particularly you're new to wave forms to making some of these concepts a little bit more concrete. Uh, so to begin, when we think about flow through a centrifugal flow or a continuous flow, l vod, it's really dependent on three factors. The first is the speed that is set in that pump is now, or that Roeder is pushing blood across the pressure head, and that pressure head is the pressure difference between between two chambers. That's the pressure in the left ventricle is demonstrated in this dark red line in the bottom. So we see LV systolic pressure increase during sisterly, and then the pink pressure, which is pressure in the aorta and the pressure head or the Delta P. The pressure in the aorta minus the left ventricle varies across the cardiac cycle as the LV contract, so that pressure head is at a minimum insistently. And because of that, when the L V is contracting, there is acceleration of flow through the L bad and that acceleration decreases in diastolic when the pressure head is the Gradus. And it's that concept that leads to the generation of H. Fahd wave forms and the concept of flow, pulse utility and a continuous flow device at a very simplistic level. One way to think about it as the LV is contracting it is augmenting or squeezing additional blood into the device. So it's really the degree of pulse utility represents the native lvs contribution to flow through a centrifugal flow pump. We see that here on this slide in an L V that is perhaps under filled that, and so again, in this low blue line on the bottom, we see increasing pressure insistently But the difference in the pressure head across the cardiac cycle are going to be minimized in an under filled left ventricle, which is going to translate to a low degree of pulse it till it e is seen in the panel on the right, in contrast, in the panels on the bottom. If the L V has higher pre load or even greater contract, I'll reserve we're going to see greater pressure generation insistently, which is going to lead to a lower pressure difference between the aorta and the left ventricle insistently so the pressure difference across the cardiac cycle is going to be higher. So in this example, we have a pressure difference between diastolic in 60 insistently of about 60 compared to 20 and the example above. And that translates to higher pulse utility a flow through the device itself. And again, right now we're focusing on device pulse utility, which correlates with but doesn't necessarily equate to pulse utility in the patient or the arterial system. And we will review that concept with some of the case examples and so understanding the patient pump interaction really gets down to your understanding of heart failure in general. because anything that affects left ventricular function and these are the three concepts we think about in the management of heart failure, which is pre load after load and contract ill itty. All three of those variables impact, uh, device function, and h that waveform so again, under filling of the left ventricle, will lead to reduced LV systolic contraction, which will minimize the degree of pulse utility in the device. High after load, in contrast, is going to decrease device flow just like it would decrease native LV flow. But it actually translates to higher pulse utility, and we'll look again, an example of why that occurs and then contract till it and I mentioned this concept of contract tile reserve. So if an L V has a higher baseline stroke volume, that will translate perhaps into a higher degree of H bad flow pulse utility and then lastly, this cartoon which kind of ties this together. So what we want to avoid when we think about speed optimization is this first area where an LV is under supported, it is not adequately unloaded. The device is not providing enough support where we have a high degree of residual pulse utility, the L V is doing a lot of the work in diastolic. We see that the trough could in fact fall below zero, which we absolutely want to avoid, because that means we could be having regurgitating flow through the device. As we ramp up the speed, we augment average flows or mean flows leading to greater unloading in the left ventricle. Less pulse utility until we hit a region whereby we could have a complete laminar flow, which may result in Internet and partial suction events. And that's the area that we want to avoid because it doesn't give a cushion for the patient as it relates to physiologic changes that could acutely decrease pre load, uh, such as coughing, straining, standing up, walking around, Um, and in the absence of that cushion, those could precipitate intermittent partial suction events versus all out suction. And so we'll look at how wave form profiles with even provoke a bill. Maneuvers may help to assist device optimization in addition to other standard ways of doing that, such as echo and right heart catheterization. Uh, and then, lastly, the rules of two. So here we have a nice sinew soil normal h bad away form. The rules of two are that we want the flow pulse amplitude. So the difference between the peak and the trough to be on average at least two leaders are greater. And we want that trough to be higher than two liters per minute. And the example I showed before in the cartoon again. Avoidance of the troughs falling near zero or worse below. Which means there is regurgitation flow down the inflow. I'm sorry, the outflow cannula of the L, that versus a low pulse, a tile state. And we'll do some case examples of this as well as reviewing again high pulse style conditions in what the differential diagnosis is. So with that, let's jump right in to our first scenario. Um and I'm going to ask Jen if I made to help walk us through this, which so, Jen, this is a 37 year old patient and you're called as a you know, a lead bad coordinator person with most knowledge of these devices in the hospital to assist the bedside nurse because she sees something that she recognizes is abnormal, and she thinks it's suction. But frankly, she's not sure what she's seeing. So maybe you can walk us through what we're seeing and what your thought processes. Sure. So, um, this does look like a very abnormal waveform are flows are okay. There are 3.5 with a baseline of four. Our powers are totally fine. Um, but the pulse utility, you can't sort of distinguish what's happening. And you have these negative deflections toward zero, which are normally section. But what's very important here is that we're immediately post up and still have a balloon pump in. That's at 1 to 2. So these abnormal contours of these wave forms show the reflective of when the balloon inflates and you have a temporary obstruction of flow, it creates that negative deflection down. So this isn't something that we is necessarily abnormal when you have a balloon pump in as you were in the balloon pump and take it out that those waveform should return to normal. Perfect. Yeah, exactly. Right. Thank you. And, uh, again highlights some of the discussion from last week when we're seeing irregular, um, trends, impulsive ability. Um, we often think about arrhythmia related, and that's usually more pertinent in terms of the peak to peak intervals. Um, versus, uh, irregularities in the pulse utility. And we saw the impact of the LEVAR Recycle last week, and this very much is totally regular device function in the setting of a balloon pump and just to explore what John was saying a little bit more. And why that occurs is a review of what occurs with balloon pump inflation. So we use these devices to increase blood pressure and to decrease after load and someone with acute on chronic heart failure with a shock condition. The red line here is an arterial tracing. So with in diastolic, we have the democratic notch, which triggers, which means that indicates closure of the aortic valve. So that's the diastolic period. And with the balloon pump in place, the balloon pump inflates in diastolic at the time of the aortic valve closure to augment diastolic pressure that helps with coronary profusion and increasing a systemic profusion. So that's the augmented diastolic pressure. Of course, higher pressure in diastolic in the aorta is going to further increase the pressure head that we just discussed to the extent where it may actually cause record latent flow or at least Stasis in the device at the time of balloon inflation. So something we do want to avoid in the in the H fat weight forms here. In contrast to the last picture, this is a balloon pump, actually at 1 to 1. So at least in this example, you can see that the flows are not approaching zero in diastolic like we saw with the last one, Uh, not uncommon for patients to come out of the operating room with balloon pumps in. Oftentimes, it could be coagulate pathetic at the time of surgery. But when we do see this, generally speaking, at least in our institution, we dropped the balloon pump to 1 to 2 or 1 to 3 until we think it can be safely removed. Because balloon pump certainly don't after load reducing. L've at if anything, you can think about it when that it's a continuous flow device and that continuous flow is being now interrupted in diastolic with balloon pump inflation. I have a question for you, and maybe Jane can comment on it. So, um, in a patient on 1 to 2, if it would you ever reduce the augmentation of the balloon pump. If you approach zero and the wave form with the L that or we just say it 1 to 2 and stop. I think in that I have not. To be honest, I've never adjusted the augmentation of the balloon pump in that setting. I mean, we may think about dropping it to 123 if that's what you're asking and then really kind of working with the surgical team in the intensive this team, just try to get that out sooner rather than later. I agree. Trying to get it out is probably the best move assess. If you needed to assess the waveform, you could pause it for a little bit. But I think taking it out is probably definitely something to be aware of. That I have. I have been called without question to the bedside to help diagnose and troubleshoot this on more than one occasion. Okay, so, Dr Judy, we're going to move on to you here for for a case number two. So we have a 52 year old now who's a couple years post H fat implant who is presenting to clinic um, plugged into the monitor. This is what you see, um and he does report that, you know, he's not quite as active as he was. He's feeling a little bit more disk nick with activities that weren't causing him difficulties 6 to 12 months ago. He's definitely slowing down. He noticed a little bit more swelling in shortness of breath. So, um, again, you know, the power of this device is the dynamic display that you can get that you can put in in the clinical context of the scenario. So you have several years out, um, and H five presentation and the waveform is giving you a low possibility, high flow. And whenever Whenever you see that the two things that pop in my mind is Are we dealing with the thrombosis or we're dealing with aortic valve pathology, specifically aortic valve regurgitation. Um, you can quickly discern this from talking the patient in terms of history that can suggest if there's an issue with the pump or, um, and if there is none, then you can do an echocardiogram that can show you evidence of AI. You know, we know that you know about, uh, you know, at three years, about 30% of that patients will have some issues with the aortic valve, specifically aortic regurgitation. And you know, we can underestimate the severity because it's a continuous AI because it continues to flow. Pump across the aortic valve. So this is a this is suggestive of of of A I at least from that wave form that you're seeing. Great. Yeah. I mean, honestly, we could spend the next 45 minutes, I think, talking about this case alone, we won't. But I think there is some stuff to dive into. So just in terms of nuts and bolts of clinical management, So this certainly would raise red flags about the presence of a I, as would anyone, I think, coming in with symptoms of heart failure. Who is 3 to 4 years out from l VAT etcetera. So how often Marwan are you screening your patients for development of valvular heart disease? Or do you do regular screening echoes So routinely, we do an echocardiogram in clinic in asymptomatic patients every six months, just if they're looking at the different parameters, including the aortic valve. If there are symptomatic or they have evidence of at least moderate Ai and I think we can increase the frequency to three months and couple that with invasive him with dynamics. Um, and not just noninvasive assessment of the Yuri valve. What about you, Mike and Jen? Yeah, we did the same thing every six months routinely on asymptomatic patients. I would say, um, a I is one of the things that scares me the most. Um, it's it's a tough, tough thing to handle, um, for sure in these patients. So I think identifying it, optimizing speed for it. And, um, no England to intervene or all some pretty, pretty hard things that aren't easy to navigate. Yeah, there are no right answers here, and we're gonna We're gonna put it back in marlins lap in a second. But I agree. You know, there's a whole philosophy about Do we let the valve open regularly? So we don't have, uh, commit sure, fusion over time, which can provoke a I, um but Marwan mentioned in doing an invasive evaluation, I think that's really critically important because it's very often that right heart failure in a i r co prevalent, they come, they come together, and it's hard to distinguish. Oftentimes, is the patient's symptoms driven by the right heart failure? Or is it driven by the eye? Because if we start talking about intervening on the eye, which may not be a low risk procedure, it's hard to define how much better we expect the patients symptoms to be. So I absolutely agree with thinking about things like a right heart capitalization to look for the degree of unloading. I mean, if we're sitting with a wedge pressure that's 25 not improving with the ramps feed study because you can't unload an L V that's got high amount of aortic regurgitation. In contrast, you know, if you haven't if you have a wedge, that's 13 with an R A of 20 because both of those could be low systemic cardiac output states, then that's going to help distinguish potentially more of a right heart failure state than an AI state. I'm going to ask more on how he approaches as an interventional heart failure specialist, the question of Tomur versus surgery, but really quickly just want to run through because this is a waveform boot camp. Why AI translates to low pulse utility so it's high flow because you essentially have a runaway VAT. You know you're sucking blood from the L V into a device out the aorta, and it's immediately being sucked back into the device. But as it relates to the pulse utility again, it's about the changes in pressure across the cardiac cycle. So in a normal patient, not an L VAD patient, remember insistently there is no pressure. Gradient. The pressure in the aorta and the left ventricle are the same when the valve is open and diastolic when the valve is closed. There's, of course, a pressure gradient of about 50 to 60 between aortic diastolic and LV and diastolic pressure. In a I two things happen. So one we talk about a widened arterial pulse pressure. So you have dropping an aortic diastolic pressure, and at the same time, because you're not unloading the LV, you're having a regurgitation flow. You have a rise in L V and diastolic pressure, so those two things lead to a decrease in the pressure gradient in diastolic between the left ventricle and the ordinates. That concept, now a reduced pressure difference or pressure head in diastolic, is going to translate to a low degree of pulse utility, potentially on the H bad wave forms. All right, so with that explanation for the wave forms, you know, we'll close this out with asking Morrow. And what do you think you have? I actually don't have a lot of experience with top over. It certainly talked a lot about in the in the community. But is that is that a procedure? You do? Yes, we we. So the way we approach bad patients specifically with modest, severe ai, um, depends on if the human dynamics support the need for an intervention number. One of our is a patient listed for transplant. We're dealing with the DT patient. That's question number one. Question number two If it's an old that you know, the practice, at least from the surgery perspective, Um, a while back, not so much now is do they stitch? Do they have a park stitch on the valve or not? Number three, the age of the patient and classification of the ambulance, um, is a patient at high risk or we do. If they are listed. Um, can we listen for an exception or not? But after looking at everything, and if we deem that the patient requires, uh, an invention of the year exile we've done, Um um Tavern, you know, to be the classic Teaching is a self expanding valve in a not so heavily calcified Angelus is probably a better approach than a balloon expandable valve. Um, but we've done a few balloon expandable valves without any problems, as long as you oversize it from a technical perspective. The bottom line is a lot of factors, um, going to play into place when you decide what to do. For those patients, it stems from whether we're dealing with D T versus BT, surgical candidacy and surgical risk. Um, technically, can you do it if you decide it's pretty genius and technically, can you do it if it's surgical or not? Outstanding. And may I ask you guys, in my experience of visiting a lot of bad programs, this is one of the most common findings that sometimes overlooked, particularly like you, said Dr Kernan, because it's mixed in with the patient. That's kind of got ongoing heart failure symptoms. So as they're progressing worse and worse than the heart failure, maybe some right heart failure, Um, kind of the whole picture is sometimes missed, so I was gonna ask, um, two questions. Is there one finding just on the way for? Of course, it's not diagnostic. You don't know what's really going on. But is there one thing that keys you into like, Ah, let's get an echo number one and two. What do you do? Uh, what do you do in the short term? Right. You know, you're going to work this patient up for a potential, um, intervention and a fix here, um, and assess them. But what do you do, right? You know, when you see them and they're symptomatic. Well, I think in terms of your first question, it's always, you know, it always re emphasis. You know, there's incredible amount of information in the wave forms, but it always needs to be taken in the context of the rest of the patient. And that includes exam. Echo is always the first other diagnostic modality. And then in right heart, cath is usually step to down the road in terms of thinking about optimization. Um, you know, we would do an echo optimization. My experiences. It doesn't usually not terribly helpful, But remember that theoretically, at a higher speed, what you're doing is going to increase aortic pressure. But at the same time, you're going to be unloading the left ventricle. So now you're going to be. We were talking about the pressure gradient across the L VOD, but now we're going to talk about the pressure gradient across the aortic valve. So if you're increasing your aortic root pressure because of decreased LV outflow in the same time, decrease increasing aortic root pressure decreasing left ventricular pressure because you're unloading with the device that's going to increase agreement across the valve and could theoretically worsen ai. So usually we're looking to minimize feed a little bit. But, you know, if you have a outflow cannula that may be regulated and shooting blood up the aortic root, you know, we've seen cases sometimes where higher speed may look better. But honestly, it's a surgical. As marijuana was saying, You really need a procedure. If the patient's a candidate, we can tinker with the L VAD we can work with after load reduction, but at the end of the day, it's kind of really a surgical problem. So, actually, you know, you just mentioned that producing the pump speed um, I don't know if I'm going to disagree with you on this or not. But, um, in the short term, don't you think that going up on the pump speed and someone who is symptomatic with heart failure is going to give them some benefit? Until you get to a more definitive approach, as opposed to lowering the pumps, people is going to take away from the better and in theory, reduce the AI. But when you're dealing with high, LVPD is gonna be a problem. So, yeah, like I totally agree. I you know, I think it's a case to case, and it's hard to predict how a patient's going to respond. I think the initial teaching when we learned about this from a physiologic perspective, is where I started. But I think in a clinical in a real life situation, often we do exactly what you just said. 100%. Okay. All right. So, um, that's what was you know, and this is just a rounding up. The intervention that was done was considered taboo versus surgery. Okay, so scenario three, we'll stick with tomorrow. And if that's okay for this one, I often find that this can be a great masqueraders and one of the more challenging ones to diagnose. But a 64 year old female, another remote implantation 4.5 years ago have been doing well now presents with, uh, you know, an isolated little flow alarm as well as some symptoms of progressive heart failure. What do you think? So again, you know, looking at the looking at just the wave forms, you can see there is evidence of low flow, low pulse utility. And if we remember, you know the differential diagnosis when we're dealing with low flow. Low possibility is, you know, the volume on the L V is reduced, whether it's because of hyperbole, Mia or the RVs down or temple, not features that you can see early on post op. You mentioned this patient had a bad several years ago. And whenever that happens and you have to think about, are we dealing with an inflow and outflow obstruction of the of the pump itself? Um, as as as as as a possibility and from my experience, typically see a lot more outflow issues compared to inflow issues on the pump itself. So if I have to, if I have to guess one of them, I'd probably give him the sneer that you presented. We're dealing with an issue of the outflow graft perfect and to highlight. So once that differential again, it's really going to be the echo in the exam that's going to help TV set out, and we'll talk about some other that interrogation strategies. But in the patient with right heart failure with low pulse utility low flow, you're going to likely have a left ventricle that is unloaded. The problem is in the L V. So now we're going to expand into that concept that can be confusing as it relates to thinking about patient pulse utility versus device pulse utility. So if there is an obstruction in the L VAD circuit anywhere along the circuit, there's going to be decreased blood flow through the L VAD. So the L that is not going to see any pulse utility when the left ventricle is contracting. Now the patient is actually going to be very pulse a tile. So in the setting of of inflow and outflow obstruction, you would expect the aortic valve to be opening very regularly, and that's going to tell you that uh, there is a problem. There is device malfunction, particularly if the aortic valve was closed predominantly on the most proximal echo before this presentation. So in that setting, again, the L V is contracting. But now that pulse, a tile flow is going out the native circulation meaning out the aortic valve rather than ejecting into the the pump into the H That so that is going to help you differentiate what the underlying diagnosis is in that setting. So oftentimes the next clinical assessment would be doing a C t. A of the heart and the device to look for obstruction. In that circuit, you can obviously see inflow cannula obstruction very easily with CT scanning. But it can be very helpful to diagnose Qingqing or obstruction of the outflow cannula. And here at that red arrow, you can see what appears to be a stone attic area just proximal to the aortic anastomosis. And we've certainly seen this, uh, in a number of patients. Um, So, Martin, what would you do in this setting? Um, what would be the practice? So we'll start with invasive him with dynamics, assessing whether Cath looking at whether the lvs loaded or not assessing the RV. And then, um oftentimes, um, if we demonstrate on CT scan with three D reconstruction, there is evidence of cyanosis or king sometimes really not, uh, easy to discern. Um, the issues that may arise either at the anastomosis of the outflow graft to the aorta. Or sometimes you see it, um, a kink in the middle of the outflow graft. Either way, we can we can do a human dynamic assessment on the left side, Uh, looking at the grading across that. And if that is significant, then then again, depending on the patient, um, whether there are candidates for redo operation to fix the telegraph. Um uh, listing if there are on the transplant list or fixing it per continuously. And we've been successful in, um, I want to say in the past five years, about 15 to 20 of those have been scented successfully with with with a stent in the cath lab, and you'll see an immediate improvement in the the human dynamics as well as the wave forms on the pump. Great, they can occur. You know, I'm not a surgeon, is my disclosure, but we've seen that depending on the on the material that sometimes surgeons used to cover the graft, and the intent of that is to reduce the amount of adhesions to make re entry into the chest of the patient, whose Bt, at the time of transplant surgery easier. But there was some materials that were more prone to when there's some seepage out of the outflow graft that could build up pressure in between the potential space between that covering, which could then lead to that cinematic area in the in the outflow graft. So we would do the same thing. I mean, oftentimes we have just like yourself, someone who is both an interventional list and heart failure specialist. And they would put a pressure wire down the outflow graft, the document, the severity of the stenosis. And if it looks significant, think about stenting, and what's really rewarding is you see that impact immediately on the waveform, so you'll see the waveform is going from non pulsar tile. Repulsive tile is flow is restored through the device in an immediate augmentation of the average flows. Once that stent is deployed and this is just again just to highlight the principles of functioning, L VOD will focus on the right panels here, but again, in an unsupported left ventricle. We talked about this last week and a little bit earlier. This talk you have left ventricular pressure with his economic contraction systolic ejection, where the aortic valve opens and then diastolic with isil. Olympic relaxation as we further unload the L VAD with ramping up l've at speed as the L V. Does the L VAD does more and more work more the pumping? We're going to gradually decompress or unload the left ventricle leading to uncoupling of those two wave forms. So in panel see, the aortic valve would still be opening. But it's what we see. An echo. It's not full leaflet tip excursion. It's partially opening each cardiac cycle and then d any we would see that the aortic valve is no longer opening at all. So as the speed goes up, we have a reduction in LV systolic pressure. That's what we see in the pressure volume loops, as well as an overall decrease in the volumes. The end, diastolic and systolic volumes in the heart. That's what we're calling unloading of the left ventricle. Here is a case study of that which we did an H at patient with a presumed device malfunction. And in fact, what we saw by putting a pressure wire in the left ventricle is that this left ventricular waveform was appropriately uncoupled from the aortic waveform. So this actually highlights, in fact, normal. L've add function in this patient. All right, we're gonna move on to the next, uh, scenario. Oh, sorry. Here again, just to round up this case. The patient was taken to the O. R. Wasn't stent ID. The vascular graph was repaired. Uh um and we see now normalization of pulse utility as well as flows in this in this patient. So, Jen, let me pull you back into the conversation here for case four, if I may. So we have a 38 year old now we're going back to the somewhat early postoperative period. The patient's transitioned out of the unit on the heart failure Step down unit. And once again, you're called by an astute bedside nurse who noticed when the patient sleeping, particularly on the left side, that there is an irregularity. There we go. Highlight that here in the in the each bad waveform. So Can you describe that and let us know what you're thinking? Sure. So, um, we notice here. Also, the flow is a little bit higher than normal. Reading 7.4, the baseline of 6.5. Our power is okay. Our pulse utility Baseline being five. And you can see here are our pulse utilities about three. And it looks pretty normal in the in the beginning. And then as time goes on, you see, we have intermittent suction. Um, So it becomes variable at the end and a little irregular. Um, so definitely not a normal waveform there at the end. And as you mentioned, this happens when the patient lays on his left side. So, um, we're certainly going to think Is this positional? Um, you know, there's arrhythmias that we're also thinking about, but particularly that hint of him being on his left side. Um, it's important. Then you know what happens when he's on his right side. Has anything else happened? Are there any other position changes? Um, so that would be what I'm thinking about first here. Great. Yeah. Um, and so it is. And it is positional. And I would agree with you It's not just positional isn't really a diagnosis. I would say this is positional partial suction events that are occurring when the patient is on his or her left side, which is what we see. But I would also like you. The patients are almost universally on telemetry, so you certainly want to look in the corner of the room to make sure that it wasn't runs of non sustained V T that could be potentially triggering this. And in the absence of that, then we're really left with positional related partial suction events. So the question is what you know. What's causing that. And the most common ideology would be a potential sub optimal positioning of the inflow cannula where it could be SEPTA Lee, Angular waited where there can be some compression that are of of that side when the patients lying on the left that leads to these partial suction events. So we've seen that in my response to it would be to decrease the speed the patients at a moderate speed at 26 62 slowly back off the speed and doing so you actually may see resolution of that condition whereby we're no longer having that problem because I've certainly seen it occur again because these troughs can drop so low. Where the patient goes home lies on his left side. And now we're getting called at two in the morning with low flow alarm. So it's definitely something to be aware of. And this is something that we want an echo. We want some imaging, and then we do some waveform optimization with bedside speed changes in maneuvers. I think also to add to that optimizing their fluid status is important when they're dry. This is just going to be exasperated. Yep, So it's definitely need their tanks to be more full if this is a problem. And unfortunately you can't reposition l vod. So even under the best of circumstances, sometimes you know, not all patients are as dilated as others. You may have the best surgeon in the world, but still be left with with seeing this condition. At times, you had mentioned something. Oh, sorry. But you had mentioned high flow morrow and I'll jump back to you just a second. Can you Can you tell me? You know the flows are pretty high. Can you talk about that? A little bit. Sure. So, um, we know that flow is estimation of speed, power and hematocrit. Um, so are hematocrit in the case, I believe was 24. Um, so the first question is that accurate? Um, as your hematocrit is lower, your flows are going to be higher. Um, and vice versa. So it's important to know that, uh, it's not. Your flows aren't changing. When you update your hematocrit, you're just getting more accurate representation of what is actually happening. Um, so in this particular patient there hematocrit, I believe, is, um actually, they got maybe some transfusions and when they were transfused two units. Sorry. Yes, I left that out. You're exactly right. Yeah. So his his manager actually being closer to 36. When you update that in the monitor, you're just going to get a more accurate representation of flow. It will come down. Um, probably into the 5.5. 6 range. Perfect. Yes. Remember everybody we talked about last week. That flow is estimated in its generated by three variables. The fixed speed, which we set the power required to maintain that fixed speed against the pressure head, which is directly measured And then the viscosity setting, which is estimated by the patient's inadequate. So you can think about it that if the patient has is anemic, their blood is thin, flows will be higher. If the blood is thick, flows will be lower. And so the converse is true if if, um adequate setting is set higher than the patients, inadequate actually is, and the flow is going to be underestimated. But it is, in fact, that viscosity setting that allows flow estimation to be more accurate with centrifugal flow devices. Marlon, I interrupted. You apologize? Well, I just wanted to, um, just can you share your thoughts with us? So, um, you think about Canada position? Um, can you tell from this way form that this is the issue as opposed to let's keep the tank full, your approach to choose to lower the RPMs as opposed to giving volume, for example, is there a way that you can tell based on that way form or not? Not really. I don't think, by the way, for Malone. I think that's what the you know exam is the J BP elevators. The patient look dry and then imaging both chest X Ray is you know, even when it's p A and lateral is not great at being able to tell us. So oftentimes, if we're getting alarms, we'll do a CT scan to better visualize where the inflow cannula is situated in the left ventricle. Do you see this issue more with April calculation versus non April cancellations of divide of, uh, H fads? Or not necessarily, I would say I don't have limited experience were predominantly in a pickle cancellation, Um, center. So I can't comment on a comparison there. But I mentioned last week we had a patient who had a door procedure, which is an LV aneurysm. Surgical repair. So they had their their the geometry of the LV was abnormal and that patient had an l. That and we saw very. We saw wave forms that we can, no matter what we weren't able to persistently, chronically looked just like this. Because of that, she wasn't terribly dilated. And again, I just had to do with the positioning of the inflow cannula. Okay, but thankfully, symptomatically, she's been fine. Okay, we're gonna move a little bit more quickly through these last few scenarios because I do want to get to the log file analysis. By the way, this is what John had said. So the inadequate setting was appropriately updated to 36. And now flows are are back within the normal range. Um, an interesting case that I had. I was called to the unit because the patient was having that was very de conditioned. Post surgery was having trouble standing with physical therapy because each time PT stood up, the patient, the telemetry bells were going off and they were having non sustained runs. VT. So the patient was having non sustained V t. That was positional in nature. So I went into the bedside. I didn't have anybody with me to help stand up the patient. So I asked this patient to do a quick Val Salva maneuver. Of course, Val Salva. Well, let's just see what happens first and then we can talk about it. Oh, sorry. I may have advanced, at least on my screen. Advanced one too many. Um, if we could play that video again, I'm not sure if it was visible to everybody that suddenly he what almost looks like suction events that are very rapid that play through and so that occurred. I'm staring at the HD monitor as well as up at the corner of the room and telemetry. And sure enough, the patient had a prolonged run of non sustained VT. And three nurses ran into the room to see what's going on in the patient. And so in that setting, when we're when we're doing about Salva, we're increasing intra thoracic pressure. So we're going to decrease Venus return, were decreasing pre load to the left ventricle. And because of that, if the LV is now under filling, the inflow cannula can come in contact with the septum. And so septal contact that can tickle the septum and and cause a run of non sustained ventricular tachycardia can provoke arrhythmias. So by doing a simple speed reduction here from 2800, um, down to 28 60 down 60 RPMs to 2800 will play the next clip and we'll see. This is just a minute later with that speed change. I had the patient Val Salva again, Uh, and there is no VT induced by the Val Salva. And here you can see now an augmentation of pulse utility during the Val Salva maneuver. And that occurs because when you also Val Salva increasing intra thoracic pressure, you're increasing after load to the device. Uh, and we know that hypertension or increased after load can can lead to augmented pulse utility and a reduction of flow. And we'll look at that in the log files for the sake of time. I don't want to spend much time here. This was This was an interesting case just to highlight how sensitive each that way forms are too small changes in cardiac physiology. This was an astute e p fellow of mine that called me over the weekend. It was post op Day one. We're turning the patient's defibrillator back on. He had a bi ventricular peacemaker, and the fellow noted that when he turned on the left ventricular pacing lead that there was an augmented degree of pulse utility in the H. God wave forms in a slight increase in flow. So not a lot to learn as it relates to diagnosis and troubleshooting, but just highlighting again the power of information that could be contained and how sensitive um, wave forms are too small changes that can occur in cardiac function in this setting. In fact, with the L V pacing lead on, we see that the patient was having more frequent partial intermittent suction. So not the nice sinew soil pattern we're seeing at the tail end of that wave form. So, in fact, we leave the LV lead off in most of our patients to preserve generator life. You know, if there's time at the end of this, I'd like to know Marwan and Jen's practices regarding, um, I, c. D or CRT device management. But like I mentioned, I do want to make sure we get to a couple of cases here at the end. Uh, we'll we'll end really with this case before log files. So, um, Jen, because I do think this is an important one. This is a patient who presents to the emergency department 65 6 months post transplant, who called with some palpitations and a low flow alarm. Generally looks okay, but it's a you know, a little bit more breathless and short winded. Looking at this, if you can quickly walk us through what you think, sure, so his. The first thing you know this is that this patient is tachycardic their heart rates got to be high. We're looking at the right time scale. Where? On 10 seconds. Um, you know, our amplitude is okay. Are flows are a little bit lower. The power is fine, but that is the first thing to take away from this wave form. Um, so next I would look at their telly, get an e k g and see what's happening. Um, this, uh, particular patient, Mike, if you want to go to the next slide, Um, uh, we see that we're in ventricular tachycardia sauce with a heart rate of 151. So, um, I don't even think we need all of these human dynamics that, you know, I'm not necessarily worried about their wedge pressure right now. And they're CVP because while of that patient will tolerate VT better than a non bad patient. Eventually, something's going to Peter out their RVs gonna take a hit. Um, so the first move here is to get them out of the T. And the biggest thing I would say is definitely sedate these patients because they are awake normally. Um, and tolerating this pretty well so you can see this patient got cardio overdid, and immediately there wave forms returned to normal. So this was This is an easy fix, but definitely important to do it timely. Yep, I don't have much to add. I'm sure everyone is aware that patients on this call that patients with L. VADs can tolerate VT oftentimes better than those without L VADs, so they certainly can walk into clinic or the emergency department. But just as Jen noted, it's not going to last forever. So we do wanna We do want to do a controlled cardioversion chemical or electrical, but making sure the patients to date. So that's great. Okay, let's jump past these last two cases and dive into, uh, the power of of log file analysis to further assist is one more tool to assist in the diagnosis. Um, we mentioned that flow is estimated already based on these parameters. One thing I did want to highlight is everyone should be familiar with the power speed um, graph that we have here, where you can plot a patient speed and make sure that their power is falling in within the range of normal. Because if you have a power that's outside of the range of normal that would be consistent with an abnormal state, namely if it was higher than expected. Most commonly, it would be thrombosis if it was lower than expected. It may be obstruction like Dr Julian was speaking on on previously, but what log files do is they capture, Um, this information from the wave forms every 15 minutes, and it converts it into trends over time. A lot of this data is, you're aware, can be looked at real time just in the history page of the H God monitor. And then we also have the opportunity to send log file reports, which we do pretty routinely, and you get that back instantaneously with an interpretation. Just to confirm your own suspicions is too much going on in these patients as well? So again, log files are showing historical trends about what's going on as it relates to trends in power flow and pulse until it e in our patients and also, of course, capturing any alarm states. This is what the log file trend would look like going up here to the waveform. So we have the peak in the trough, and then the green is the average flow. So now we're talking about peak flow, trough flow, average flow. That's the dark green. That's what we're reading in the upper left hand corner of the monitor. So it's showing us average flow here over a 30 day period. The light green is the degree of flow pulse utility or the amplitude, so the peak in the trough of the flow. So if that's minimized and we'll see in some case examples, that would mean low pulse utility during those conditions. Trends in power. And then, of course, the black is the speed which you always want to look at because if there is a change in speed, that's going to translate to changes in flow estimation. And then lastly, before we dive into a few cases, is just to be aware of this circadian pattern. So flow is greatest during the waking hours in a patient who is ambulatory so as were up and about moving around during the day, we have increased venous return being pumped from our skeletal muscles, and then when we're sleeping, flow is at a low overnight, so that is a healthy circadian pattern to log files as you'll see in some of the examples and patients who are very sedentary, Um, or who are oftentimes hospitalized in bed. You lose that beautiful circadian pattern. Um, uh, that we're seeing here. So, uh, tomorrow and maybe or Jan, actually, can you hop into this first case and just tell us again? There's no mysteries here at the end of the webinar about what we're looking at. But if you can just describe what you're seeing with this log file analysis and comment whether or not you would, this would trigger any changes in your mind to device settings. Sure. So what? I'm looking here. You know, we have that nice circadian rhythm as you mentioned, but this green shading of our pulse utility that's just all over the place. And we have all of these spikes downward. So, um, if this is not, I would bring this patient in, take a look at their log files, look at their volume status and figure out exactly what's happening. Because this is definitely concerning. I you know, how do they feel? There could be a lot into this, but it's pretty easy to tell with that green shading all deflecting downwards that you're having some suction here. Completely agreed. So I think to me this would trigger, you know, an echo optimization. There's high degree of pulse utility, and there's lots of suction. So we need to know what's going on in this ventricle and see if there's anything we could do to optimize and avoid. You know, our suspicion is that intermittent suction events may be related to adverse, you know, Huma compatibility events that needs to be studied prospectively, but I think certainly want to avoid this burden of intermittent suction that we're seeing in the waveform again just to highlight. So without even log files, you can trend data over tying four hours 12 hours, 20 for a week, 14 days and even 30 on on the HD monitors. So these were just some clips that I took from our patients. This was a deep downward, you know, an isolated suction event. But if the patient's asymptomatic, this actually looks fairly clean. I might not make changes. This was a patient came into the E. D with a single episode who got dehydrated. You could see volume depletion over 2 to 3 days in advance with the deep negative suction downward deflection and then with resuscitation, so different trends that you can see even without sending log files. But we would always send log files in addition to this. Um, that can help assist to make sure that we're interpreting things accurately. And there's nothing else we're missing. And so, marijuana, if you want to maybe talk about what? You're what you're seeing in this scenario one that we all fear and dread. Yeah. So, you know, you have two examples here, you know, it's written there thrombosis. You can see the flow and power consumption are stable until towards the end of the, uh, the, uh the, uh, log follow. You see, there is an acute rise in and power consumption. You know, you have a set speed, and the pump is going to try and maintain that Set speed and flow is, as you mentioned, is a function of power consumption. So the flow will automatically go up doesn't mean that there is flow through the pump. This can be either an acute response that can happen because of because of Thomas. And then you can see, I think, on the right side, probably an intervention that led to the resolution of the issue, and you can see that pump a power and flow went back to normal after that. That's right. So, yeah, this was exactly that administration of throwing politic therapy. And you can nicely see if you, despite no change in speed, an abrupt decrease in flow, which is normal, because again, this was false flow estimation at a high level. With that in this patient, I assume probably went on to that exchange. Hence, we don't see resolution of that event. Um, we'll spend maybe just a minute here. Jen, if you want to talk about this, we kind of highlighted a little bit earlier in terms of hypertension. What we're seeing on the log files. Sure. So this is pretty reflective of what we see. Um, on their weight forms, we are flows are lower. There's not great variability Are shading here signifying our amplitude is all the way down to zero. So we can see pretty pretty easily here that this patient is hypertensive and needs an intervention to decrease after load and get the that trough greater than two. Perfect. Yeah, Just to end here. Just to highlight again in terms of the physiology of hypertension. If we have increased blood pressure, diastolic arterial pressure is going to rise. Which increases The pressure had our gradient in diastolic, and that's what accounts for increased pulse utility in a patient with With With hypertension. Uh, we're going to end here because I think some, I was told, alerted that some questions are coming in. I do just want to highlight one thing to tie in our discussion about pulse utility and the patient versus the pump. And that's this concept of obstruction. So this is an example of a potential ingestion and obstruction, and you'll see normal shaded pulse utility here, but really minimized shading or pulse utility in the l VAD. But this is a patient that, if they had a line in, would in fact likely have augmented arterial pulse utility. But the device is not seeing it. Resolution of that event with potential if it was an outflow cannula stenting in return of normal pulse utility that we see on the on the log files. Um and then, um, same thing with an arrhythmia. Sorry. Loss of pulse utility because of ventricular fibrillation. If the LV is not contracting you're gonna have laminar blood flow through that device. And then and then lastly, just to highlight that idea of loss of circadian rhythm in a patient with right heart failure. So someone who is hospitalized in bed bound, you don't see a nice circadian pattern of flow changes over the diurnal cycle. So let's end there. And Michelle, why don't you walk us through some of the questions and see if our panel great and I just like to apologize? We did receive reports that there was an interruption and we should be back on now as we apologize for that technical issue. Um, so one question from the audience here with positional partial section would you continue to reduce speed to prevent the section from occurring? Um, at the consequence of lowering the baseline, which do you think is more prone to clot formation, low baseline or impartial section? I think this is really dependent on the clinical scenario. And the patient, you know, really is why, why why suction happening? Um uh, and I think if we answer that question, I think that will become much easier in terms of how we manage the patient. I think um, the ideal thing is to maintain the rule of two. And if you deviate from that, then you can potentially have issues. Um, as Mike mentioned him, compatibility issues after that. I know. What, Mike? Your thoughts on that? No. I mean, I think it's a very, uh, patient, specific issue. And so I think you need more information. You need to see what the echo looks like. You need to know that the loading conditions, what the patient looks like. So, you know, I fully agree. I think we would attempt we would do a device optimization study. We bring the speed up, and we bring the speed down to see if we can optimize the the profile of those waveforms. But it's hard to give an absolute answer in terms of, what's more important, avoidance of suction versus a trough that's approaching zero as long as it's not. If I was getting a smoother curve with avoidance of suction and I had the trough around one leader, I'd be okay with that. So we talk about the rules of tools, but those aren't absolute. So as long as I wasn't seeing regurgitating flow, I think I would air towards higher pulse utility with the more Sinus oil smooth curve, even if that trough was lower than we generally like it to be, assuming it wasn't at or below zero. Great. One last question. Um, do you download log files as a part of your You know, every time you see patients in clinics as part of your standard practice? Or do you just download log files because you think something's wrong? Um, yeah, I'll go ahead and take that. We do it on every visit. The time it takes is not, um, it's insignificant, and the amount of information that you get back is enormous. So, um, I think other things like alarms. If you didn't know they double disconnected their power. That's going to show up on your log files. If there batteries are running low there at 500 cycles, that's going to show up on your log files. So there's more to the clinical picture, so we do it at every visit. Great, thank you. And I wish we could continue. I know that we can talk about this, especially folks like us all day long. So just a little bit of housekeeping again we wanna apologize for those technical issues. We try our best to answer questions as they come in in real time. In the event you submitted a question that was not answered, we will consult with the faculty here and respond via email to your questions. So please don't worry. We'll answer your questions. Um, if you'd like to review the content that you see today on the webinar there, there is a way. There is a way to watch this on Medtronic Academy. Just watch for a Medtronic email announcing when both of these webinars are posted to Medtronic Academy. Uh, speaking of Medtronic Academy, head on over to Medtronic academy dot com and check out additional clinical education that's assembled by our fantastic M. C s medical education team. Following this broadcast, you'll be receiving an email with an evaluation of the event we love to hear your feedback, the good, the bad and everything in between. Dr. Dr Karen in Dr Julian Miss proven Thank you for sharing your time and insights with us. The discussions here today have highlighted how specific physiologic conditions, both ideal states that we hope for in our patients and the sub optimal conditions can be reflected and illuminated, uh, in the h fed way for him. I think at one point I heard Dr Kern and say the power of the way from the power of the information and, uh, couldn't have said it better myself. So thank you. Um, you know, as clinicians it would never occur to us to see a patient in clinic around on a patient in the hospital and not look at, you know, pertinent clinical data, whether it's lab work, diagnostics or imaging looking at pump specific data both in the form of the real time waveform and controller log files similarly offers this insight into the dynamic kind of relationship between the patient's physiology and the pump in the hands of knowledgeable clinicians like yourself. This data can be instrumental in the management of the pump and in achieving the best possible possible outcomes for our patients. If you're interested in additional education or learning more about wave forms and log files, please reach out to your local Medtronic Trade field team. Thank you so much and we'll see you here again soon. Thanks, Michel. Have a great evening, everyone. Thank you. Mhm. Mhm. Yeah, yeah. Mhm, Yeah. Mhm. Mm. Mhm. Yeah. Mhm. Mhm, Mhm. Mhm! Yeah! Mhm. Mhm. Mhm! Yeah, yeah, yeah. Mhm. Mm hmm. Mm. Mhm. Mhm. Mm. Mhm. Mhm. Mm. Mhm. Yeah. Okay. Mhm. Yeah. Mm, yeah. Mhm. Yeah. Mhm. Yeah. Mm, yeah. Mhm. Mhm. Yeah, yeah.
