Transcription:
Treating Aortic Stenosis with Transcatheter Aortic Heart Valve Procedures

Melanie:    Welcome to Better edge a Northwestern medicine podcast for physicians. I'm Melanie Cole. And I invite you to listen in. As we examine treating aortic stenosis with transcatheter aortic heart valve procedures. Joining me is Dr. Ranya Sweis She's an Interventional Cardiologist and Clinical Practice Director of the Cardiology Outpatient Clinic at Northwestern Memorial Hospital and an Associate Professor of Medicine at Northwestern University Feinberg School of Medicine Dr Sweis it's a pleasure to have you join us today. Briefly, describe for us the procedure and indications for TAVR.

Dr Ranya Sweis: Thanks Melanie. Yes. TAVR is FDA approved for treating patients with severe aortic stenosis. So that is severe stenosis of the aortic valve. Patients at any risk level, so whether they're low risk for surgery or high risk for surgery are currently approved, to be treated using this method. And this is a transcatheter method that uses, mostly femoral access, to deliver a bioprosthesis that's essentially in a stent that's able to be deployed using a balloon inflation in position and that way, it allows for smaller access in the femoral artery to deliver this valve.

Melanie: Doctor, please speak about patient selection. Tell us about low risk and high-risk patients for TAVR procedure.

Dr Ranya Sweis: The TAVR procedure was first studied and first approved for patients that are inoperable and high risk. And that's really pretty standard for any new device. You investigate its feasibility and safety in patients who have no other options. And at that time, when patients were inoperable, that meant a surgeon was worried that they would die during the surgery and so would not offer them surgery. And so the TAVR procedure was approved in those patients because it's showed that treating their valve via TAVR saved their lives and decreased the death rate in patients that did not have an option for surgery because compared to medical therapy, it definitely won out and then, the studies showed that also in the high-risk patients, they did better long-term for having the TAVR compared to surgery. And we were also able to do the studies and show this on intermediate and low risk. Of course, I should clarify what low, intermediate and high risk actually means. We're talking about the patient characteristics and generally, this is determined based on other comorbidities, in addition to age and gender. So a patient with many medical problems that could include renal failure, whether they're on dialysis or not, it can include whether they've had a stroke in the past, have peripheral vascular disease, if they're diabetics, if they have had prior cardiac surgery, all of these things can contribute to making a patient high risk. And that means they will have a higher risk of morbidity and mortality related to surgery. And obviously the patients that are low risk, don't have these general characteristics. So for example, a 60-year-old patient with no other medical problems, other than aortic stenosis is considered a low-risk patient.

And a patient who's high risk is maybe an 85-year-old person who has some kidney failure, diabetic and has had a prior stroke. So you can imagine that those two patients are not going to have the same kind of surgery or even recovery afterwards. And that's how we look at the patients to help determine if they're appropriate for a TAVR. The current TAVR procedure is FDA approved for low, intermediate, high risk and inoperable patients. So all patients,

With severe symptomatic aortic stenosis are approved for TAVR. And then it takes, the clinical judgment to

help determine if this is the right choice. The little caveat is what do we do about the low-risk patients that are really young?

When we talk about a bioprosthetic valve that may last 10 to 15 years, how do we decide what the right treatment is for a patient that's in their forties and fifties? Many of these patients probably have bicuspid aortic valves. And if that is what they have, then at this time, particularly if they have concomitant aortapathy or coronary disease, their better choice may very well likely be surgical valve replacement. But as I've alluded to, it really is a case by case, patient by patient decision. It's a conversation between the physician and the patient to look at what their best option is in the current time, as well as their best long-term option. We don't want to be doing procedures now that put patients at a disadvantage 10 or 15 years from now, when then they don't have good options because of what we did before.

Melanie: So then what are some complications of the TAVR procedure and how do they compare to surgical aortic valve replacement complications?

Dr Ranya Sweis: So I talk about a few categories of complications when I'm discussing TAVR procedures with patients. First of all, the access point, particularly if we're talking about the femoral artery; we talk about possible injury to the vessel, bleeding or infection at the entry point. Now we use CT scans to plan this procedure and we get pictures of what the artery looks like. So we can predict to a certain degree where we need to enter the artery. And if we're going to have any difficulties related to peripheral vascular disease or incompatible arteries from the size standpoint, but obviously during the procedure itself, if there are any complications, we'd need to address them.

I talk about the risk of stroke. There are particles of atherosclerosis in the aorta, that could be dislodged from the device as it's passing in the aorta to the aortic valve position. There's also calcium particles on the aortic leaflets themselves that could get dislodged during the procedure. Any of these particles in the bloodstream, may go anywhere, including the head and that could result in strokes. Now the risk of that is less than 5%. And as our technique has gotten better, we've been able to reduce this risk, quite significantly. I also discuss, the potential need for pacemaker after this procedure.

So, our body or our heart's squeezing is controlled via the conduction system and the AV node runs alongside of the aortic valve. So when we place this new aortic valve in its position, it may put pressure on the AV node. And depending on if there's underlying conduction disease, whether it's recognized on EKG or whether the EKG looks normal, sometimes that can cause complete heart block so that the atrium does not conduct to the ventricle. And in that situation, the patient may need a pacemaker. This may become obvious during the procedure itself, although that tends to be a minority of the patients. Generally there may be some changes on the EKG that develop over the next 24 to 48 to 72 hours after the procedure. And if we notice any of these concerning changes, we typically monitor the patient, in the hospital after the procedure, to make sure that they will not need a pacemaker before discharge and the rates on pacemaker post TAVR, are probably in the nine to 12 range.

When you talk about surgery, obviously there's an incision in the sternum. And so there's healing, infection, bleeding at that site. There is a risk of stroke related to manipulating the aorta. In the most recent low risk study, it seemed that the risk of stroke with TAVR was less than this risk of stroke with surgery. And there's also a risk of needing a pacemaker with surgery, although that is probably more in the 3% range.

Melanie: Well then how about highly torturous iliofemoral arteries? Is there a way to navigate around this problem, doctor?

Dr Ranya Sweis: The CT that we obtain, for procedure planning definitely gives us a sense of whether this could be a problem or not. The vast majority of even tortuous arteries, once we place our wires up into the aorta will actually straighten out and not cause much of a problem. The good news is that there are two iliofemoral systems. And so if one is less torturous than the other, we can generally use that. But if either the disease is too significant or the tortuosity is too significant that it prevents us from using the femoral access, then we do have some other options for access so we can use. Probably the next least invasive option is the axillary artery, either preferentially on the left, but the right can be used as well.

And generally that is done via surgical cutdown. But we have also been able to deliver these TAVR valves using, cut down over the carotid artery. So if all these other arteries are too diseased, then we've been able to use cut down on the carotid. There are some other access options that are available to us. But now that the sheath sizes that we use are a lot smaller, we rarely have to use them such as a thoracotomy and cut down on the aorta itself, or a thoracotomy with trans atypical access. But like I mentioned, we have so many other options now because the catheter sizes are a lot smaller that we rarely need to use these more surgically invasive options.

Melanie: So how has the Northwestern team successfully used TAVR to treat failed surgical aortic valve replacement, or failed TAVR valves?

Dr Ranya Sweis: We've been using surgical valves, these bioprosthetic surgical valves for decades, and we typically, think that they last about 10 to 15 years. Although in some patients they can last even up to 20 years and they eventually may fail. If they fail, they can either fail by becoming stenotic or they can fail by becoming regurgitant and we can treat either of these, situations with TAVR valves.

Currently, TAVR procedure is FDA approved for valve in valve in the high-risk patients. And there's ongoing trials for treating valve failure in this method, in the low or intermediate risk patients. But the valve can be placed inside of a surgical valve or inside of a failed TAVR valve, in a similar fashion to how it's placed in the native annulus.

The CT planning that's done beforehand, helps determine the appropriate sizing. And there are a few items that we need to pay attention to, when we're doing this procedure. Primarily being, the position of the coronary arteries. So we measure the heights of the coronary arteries from the annulus, to make sure that there's enough clearance between, the origin of the coronary arteries and where the surgical valve is and where the TAVR valve inside the surgical valve would land.

Melanie: Isn't that fascinating. So tell us a little bit about post TAVR. Is dual antiplatelet therapy, aspirin still indicated. And if so, for how long? Speak about post-procedural medicational intervention.

Dr Ranya Sweis: Honestly, this really is a miracle of modern medicine and I often feel humbled and excited to be able to offer it to patients because many of them are having dinner in the chair that night after their procedure or up walking with physical therapy the next day. And because they don't have to recover from surgery, they're often already experiencing the improved symptoms, from no longer having aortic stenosis. In terms of their care afterwards, if there were no concerns about heart block, many of my patients are going home the next day.

So it's almost an outpatient procedure. If there's any concern about the pacemaker, we're obviously monitoring, for that potentially one or two more days. With regards to the medical therapy, patients may need adjustment of their therapy for their blood pressure. The heart has been hypertrophying this whole time that the patients have had aortic stenosis.

And so they may still have an element of diastolic heart failure. And so they may need to have diuretic treatment long-term for that. So just the mere fact that they had the valve in place does not necessarily mean that all their cardiac therapy is able to be stopped. Obviously, this is a patient by patient assessment and decision.

And then finally, to your question about the anti-platelets, there had been general consensus in the transcatheter valve therapy community, particularly for the aortic valve, that patients needed to have dual anti-platelet therapy. So aspirin plus Plavix, for at least three months post-procedure and then they can drop the Plavix and continue with aspirin. But actually at the European Society meetings in August, there was a paper that was published that actually suggested the patients do just as well with just aspirin and no dual anti-platelet therapy, unless they have another reason to be on the two medications, such as if they've had coronary stents.

So if patients do not have any other reason to be on blood thinners or anti-platelet therapies, then many of us are now transitioning to sending them home on just a single agent, aspirin.

Melanie: So then tell us about what TAVR clinical trials you've participated in at Northwestern Medicine. And what are you most excited about?

Dr Ranya Sweis: So Northwestern has been part of the Partner Clinical Trials from the beginning. We started in 2008, with a Partner, A and B on the high risk and inoperable patients, and then continued to participate in Partner 2 and Partner 3 with the low-risk patients. We celebrated with the rest of the cardiology community, the excellent results of TAVR compared to SAVR for patients that are low risk and are appropriate for transcatheter therapies. We are currently participating in the early TAVR study. So, as I mentioned earlier, patients with aortic stenosis have LVH, LV hypertrophy with time. And when they're finally treated, this LV hypertrophy does not go away and many are left with diastolic heart failure.

So now that we have a treatment that is a lot less impactful to the patient to receive, the question is, would it be better if we treat patients earlier and prevent some of this hypertrophy and potential diastolic heart failure. So the early TAVR study takes patients with severe aortic stenosis who are asymptomatic. And sometimes it's hard to tell if patients are asymptomatic or not. And if they can't confirm that 100%, then they undergo a modified Bruce Exercise Treadmill Study and as long as they meet certain parameters, they could qualify. So if they are asymptomatic, they are randomized to TAVR NOW versus TAVR when symptomatic, and then they are followed, over time.

And if they do not receive the TAVR NOW, when they are symptomatic, they would qualify to have the valve replacement via TAVR. So that's a very exciting, study because that could very well change the paradigm for how we treat aortic stenosis long-term As I also mentioned earlier, we are participating, in the low and intermediate risk, valve in valve treatment of patients with TAVR, both for surgical valve failures or TAVR valve failures. As I mentioned, it's approved for high-risk patients, but not low and intermediate risk. And so we're studying that. There's also a TAVR UNLOAD study that, is hypothesizing that patients with LV dysfunction and aortic stenosis basically are having two problems that they're fighting against. And if we, are able to treat their aortic stenosis, it might, optimize the treatment of their LV. And these are for patients with moderate stenosis. So not waiting until, they have severe stenosis. So those sort of are the primary enrolling studies that are active right now that we're excited about.

Melanie: Dr. Sweis, as we wrap up, because TAVR is now prevalent at many healthcare systems, how's Northwestern Medicine, staying cutting edge regarding TAVR and why should referring physicians consider Northwestern Medicine for their TAVR patients?

Dr Ranya Sweis: Obviously, I think experience matters. And at this point we've had 13 years of experience of implanting these valves. And as somebody who's participated in the program, since the beginning, I can tell you that what it looks like now is totally different than what it looked like for TAVR 13 years ago, when we started. Like I mentioned, TAVR is almost an outpatient procedure.

We no longer, give patients general anesthesia. So patients get sedation. They're usually pretty sleepy, mostly, mostly asleep and snoring. But that's managed by the anesthesia team and is not deep enough sedation that they require intubation. So that allows patients to recover more rapidly from their procedure itself, and of course is an advantage to patients with significant lung disease, where intubating them, could put them at risk for a prolonged intubation, and as long as patients do well, they're able to go home the next day. We're monitoring the need for pacemaker aggressively. And in patients that we have questions or concerns about, our electrophysiology colleagues might do a procedure that measures some of the intervals of their conduction system, to help us determine if, they may need a pacemaker or not. And then the obvious, comment that we made to the prior question. We are able to offer TAVR to patients through the research trials that are not necessarily available commercially. And so that may be an advantage for patients that are interested in the early TAVR study or the TAVR UNLOAD, for example.

Melanie: Thank you so much, doctor for joining us today and sharing your incredible expertise. What a fascinating topic. To refer your patient, you can call 312-NMHEART. Or you can visit our website at heart.nm.org to get connected with one of our providers. That concludes this episode of Better Edge, a Northwestern Medicine Podcast for physicians. Please remember to subscribe, rate and review this podcast and all the other Northwestern Medicine Podcasts. I'm Melanie Cole.