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New Data Offer a Sound Basis for Renal Denervation

  • Authors: Michael A. Weber, MD; Michel Azizi, MD, PhD; Michael J. Bloch, MD, FACP, FASH, FNLA, FSVM; Naomi D. Fisher, MD; Ajay J. Kirtane, MD, SM
  • CME / ABIM MOC Released: 9/29/2022
  • Valid for credit through: 9/29/2023, 11:59 PM EST
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Target Audience and Goal Statement

This activity is intended for cardiologists, nephrologists, and primary care physicians.

The goal of this activity is that learners will be better able to understand the efficacy and safety as well as the prospective role of renal denervation in the management of patients with uncontrolled hypertension.

Upon completion of this activity, participants will:

  • Have increased knowledge regarding the
    • Recent data on the efficacy and safety of renal denervation options
    • Patient perspectives on blood pressure management


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  • Michael A. Weber, MD

    Professor of Medicine
    Division of Cardiovascular Medicine
    SUNY Downstate Medical Center
    Brooklyn, New York, United States


    Michael A. Weber, MD, has the following relevant financial relationships:
    Consultant or advisor for: Ablative Solutions; Medtronic; ReCor Medical

  • Michel Azizi, MD, PhD

    Professor of Vascular Medicine
    Université Paris-Descartes
    Hôpital Européen Georges-Pompidou
    Hypertension Department
    Paris, France


    Michel Azizi, MD, PhD, has the following relevant financial relationships: 
    Consultant or advisor for: Alnylam Pharmaceuticals; Idorsia; Medtronic; Novartis; ReCor Medical 
    Speaker or member of speakers bureau for: ReCor Medical
    Research funding from: Idorsia; ReCor Medical

  • Michael J. Bloch, MD, FACP, FASH, FNLA, FSVM

    Associate Professor
    Department of Internal Medicine
    University of Nevada School of Medicine
    Medical Director of Vascular Care
    Renown Heart and Vascular Institute
    Reno, Nevada, United States


    Michael J. Bloch, MD, FACP, FASH, FNLA, FSVM, has the following relevant financial relationships:
    Consultant or advisor for: Esperion Therapeutics; Janssen; Medtronic; Novartis; ReCor Medical
    Speaker or member of speakers bureau for: Amgen; Esperion Therapeutics; Janssen
    Research funding from: Amgen; ReCor Medical 

  • Naomi D. Fisher, MD

    Associate Professor
    Harvard Medical School
    Endocrinology, Diabetes and Hypertension
    Brigham and Women’s Hospital
    Hypertension Service and Hypertension Specialty Clinic
    Boston, Massachusetts, United States


    Naomi D. Fisher, MD, has the following relevant financial relationships:
    Consultant or advisor for: Aktiia; Medtronic; ReCor Medical
    Research funding from: Aktiia; ReCor Medical

  • Ajay J. Kirtane, MD, SM

    Professor of Medicine  
    Chief Academic Officer, Center for Interventional Vascular Therapy
    Director, NYP/Columbia Cardiac Catheterization Laboratories Columbia University College of Physicians and Surgeons
    New York-Presbyterian Hospital
    New York, New York, United States


    Ajay J. Kirtane, MD, SM, has the following relevant financial relationships:
    Institutional research grant funding: To Columbia University and/or the Cardiovascular Research Foundation from Medtronic; Boston Scientific; Abbott Vascular; Amgen; CSI; Philips; ReCor Medical; Neurotronic; Biotronik; Chiesi; Bolt Medical; Magenta Medical; Canon; SoniVie; Shockwave Medical; Merck 
    Consulting and/or speaking engagements: institutional funding includes fees paid to Columbia University and/or Cardiovascular Research Foundation for which Dr. Kirtane controlled the content.  
    Personal Consulting with Interventional Medical Device Solutions (IMDS).  
    Travel Expenses/Meals from: Medtronic; Boston Scientific; Abbott Vascular; CSI; Siemens; Philips; ReCor Medical; Chiesi; OpSens; Zoll; Regeneron 


  • Asha P. Gupta, PharmD, RPh

    Associate Medical Education Director, Medscape, LLC


    Asha P. Gupta, PharmD, RPh, has no relevant financial relationships.

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    Senior Director, Accreditation and Compliance, Medscape, LLC


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    Associate Director, Accreditation and Compliance, Medscape, LLC


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New Data Offer a Sound Basis for Renal Denervation

Authors: Michael A. Weber, MD; Michel Azizi, MD, PhD; Michael J. Bloch, MD, FACP, FASH, FNLA, FSVM; Naomi D. Fisher, MD; Ajay J. Kirtane, MD, SMFaculty and Disclosures

CME / ABIM MOC Released: 9/29/2022

Valid for credit through: 9/29/2023, 11:59 PM EST


Activity Transcript

Chapter 1: Ultrasound and Radiofrequency Experience for Renal Denervation

Michael A. Weber, MD: Hello, I'm Michael Weber, professor of medicine in the Division of Cardiovascular Medicine at SUNY Downstate Medical Center in Brooklyn, New York. Welcome to this program entitled, "New Data Offer a Sound Basis for Renal Denervation". 

In each segment of this program, I'll be joined by a hypertension expert as we discuss new data, new guidance, and considerations regarding renal denervation.  In the first segment, Michel Azizi and I will discuss ultrasound, radiofrequency experience for renal denervation.

Welcome, Michel, and let's start talking about this new procedure. Could you explain to us what these different techniques are and how they manage to achieve renal denervation? 

Michel Azizi, MD, PhD: Thank you, Michael, for the introduction. Yes, there are different ways to make this renal nerve ablation. Each of these techniques, we are going to destroy the renal nerves, which are in the adventitia of the renal arteries. Either it's using low-intensity current, which is going to make a heating ablation of this renal nerves, or it's using ultrasound denervation, so highly-focus ultrasounds, which also are going to give heating lesion in which is focused inside the renal artery. 

Dr Weber: Well, that's very interesting and very important, and I think we're all excited that this new technology allows us to have a means of treating hypertension other than using drug therapy and lifestyle changes. But why do we really need denervation? Where does it fit in? 

Dr Azizi: I think we always have to keep in mind the epidemiology of hypertension, which even today, remains the first cause of disability and mortality worldwide. If there is one field in the history of medicine where you have a lot of evidence, it's hypertension because of all these trials and medications. But still today, everywhere in the world, even in your country, in the US, and in France, we are seeing that the blood pressure control is going down progressively probably because of different issues. One is the non-adherence to treatments, which is really a major issue with medications, some physician inertia to increase medication despite the high blood pressure, and probably issues around the chronicity of all other diseases which are now associated with the aging population, making taking care of this patient more and more complex. 

This is the picture where we are, so we need new ways of treating hypertension and there is no new drugs. This is why from where we started. 

Dr Weber: Now, in very broad terms, coming back to how we achieve ablation of the renal nerves, does it make a huge amount of difference whether we use ultrasound, radio frequency energy, or are the results relatively similar? 

Dr Azizi: I think if we come from the experimental models to human, so both technologies are going to reduce the activity of the sympathetic nerves within the kidney. This is demonstrated. Now, if we look at the patients and what happened in the second-generation trials, which are these sham-control, randomized the trials with optimized catheters, these trials have shown a similarity in the drop in blood pressure, which is very important. Independent trials, similar results. 

Dr Weber: Okay. Just remind us, because I think many of us have seen some of these data published in the medical journals, what are the main studies, the landmark studies, that have really pushed the field forward? 

Dr Azizi: There are really, let's say, 4 main studies using radiofrequency energy. These are the SPYRAL-HTN program, off medication, on medication; and also the RADIANCE program using ultrasound renal denervation - without medication, the SOLO trial; in resistant hypertension, the TRIO trial. 

Dr Weber: Now, those are pivotal studies obviously, very important studies. Now, I understand while we have to do studies such as the SOLO trial or the off meds trial with SPYRAL in patients not taking medications because that gives us perhaps the best view of what denervation does all by itself, but is that where we're really going to be using denervation in the future? 

Dr Azizi: You're perfectly right. Remember, when we started these trials, we were coming from SIMPLICITY HTN-3, including patients off medication gave the perfect signal of the efficacy and the drop in blood pressure induced by these technologies. But it's just the huge amount of patients, millions of patients, by definition, so we will have to select more carefully patient for- 

Dr Weber: Very important. 

Dr Azizi: ... treatment. 

Dr Weber: Now, I think many of us would regard the TRIO trial as a real tour de force because that was done in patients already taking 3 medications in an optimal combination therapy all in 1 pill. Those patients could be regarded as having true resistant hypertension. Is that the sort of patient that we're going to be looking at? 

Dr Azizi: I think, yes, because these are the patient who are at the highest risk of having an event. We know from the literature that patients with resistant hypertension have an increased mortality or morbidity within a very short time frame of 1 to 2 years. This is well-known that this increased risk is associated with the poor control in blood pressure. So I think, yes, this should be one of the populations where we apply denervation. 

Dr Weber: How long do these results last? How long does the blood pressure stay down after denervation? 

Dr Azizi: You are perfectly right and this is one of the major questions. In the trials during the first phase where the patients and the physician are blinded, we know that until 6 months, everything is okay. We can find this blood pressure lowering effect. Then patients are switched in the, let's say, real life and taken care by the physician. Fortunately, and I think it's a very important thing, we have now evidence that after 36 months follow-up, either in the SOLO trial using ultrasound renal denervation and also in the SPYRAL-HTN ON Med trial, there is a remaining and really clinically relevant drop in blood pressure which is persistent during this duration of time. 

Dr Weber: Well, that's very exciting! As far as I know, 3 years is by no means the end of it because data at 3 years, if anything, are better than they were at any other time. 

Dr Azizi: You're right. 

Dr Weber: Michel, so finally, what are likely to be the recommendations from experts in the field for who should receive treatment with renal denervation? 

Dr Azizi: Thank you, Michael. It's an important question. We had a consensus statement which was released at the European Society of Cardiology (ESC) very recently, and renal denervation may be used in adults with uncontrolled hypertension, despite being treated with 3 good and complementary antihypertensive medications. In some patients, it could be also a possible treatment option in patients who do not tolerate antihypertensive drugs in the long term. 

Dr Weber: Yes. As you pointed out earlier, so many patients just don't take their medications, and I think they're going to represent an important part of that group as well. 

Dr Azizi: Yes, absolutely. 

Dr Weber: Thank you so much, Michel. It's been delightful talking to you. 

Dr Azizi: Same thing. Thank you. 

Chapter 2: Latest Clinical Data on Ultrasound Renal Denervation: RADIANCE II

Michael A. Weber, MD: Well, we've heard a great deal already about the general picture of renal denervation. But today, at the meetings of the TCT in Boston, we heard Ajay Kirtane talk about RADIANCE II, the pivotal trial for the ultrasound method of renal denervation. And we're very fortunate to have Ajay join us now to tell us more about that study.  

Ajay, I recall you and I were co-authors on a paper 7, 8 years ago where we said the best way to understand what denervation does is to take patients off medications and really see what denervation itself can provide. Do you think that RADIANCE II, in a sense, is the ultimate way of demonstrating that approach? 

Ajay J. Kirtane, MD, SM: I'm not sure I'd say ultimate, but I will tell you that it's been a long time coming. And as you and I both know, the history of this field is really based upon the prior experiences and prior failures. At times, they were difficult. I think many of us were very disappointed with what happened previously, but out of that became this desire to re-study it with better devices, better scientific methods, and one of which includes this exact approach, which is taking patients off of medications. 

Dr Weber: Now, this obviously was a major trial. It followed on an earlier study called the RADIANCE-HTN SOLO study. In a sense, it continued it, didn't it? First of all, if you'd just give a little bit of background, what did Solo show and why did that lead to RADIANCE-HTN SOLO? 

Dr Kirtane: So RADIANCE-HTN SOLO was not a pilot study. It was actually powered for an efficacy endpoint to lower blood pressure. And in that trial, patients were taken off of their medications, randomized to denervation versus a sham procedure, and when the primary endpoint was to ascertain at 2 months, there was a significant reduction in the denervation arm and not so much in the sham arm. I'll also point out that, within that program, there was a similar parallel study, a cohort study, called RADIANCE-HTN TRIO, which were patients on medicines but stabilized on a single combination therapeutic agent. Similar results were seen, reduction with denervation compared to sham.   

We've also done durability studies, but suffice to say that in one of the designs, and I credit you for this design, actually, this feature of adding patients back on medicines later, and showing that while the durability of the blood pressure reductions with denervation were maintained, they could be maintained with less medicines added back. So, in a sense, it's a pure comparison of, one, denervation versus sham, but also a comparison of denervations plus medications, less medications compared to sham plus medications. 

Dr Weber: What kind of patients were enrolled for RADIANCE II? Were they your everyday primary care kind of patient? 

Dr Kirtane: Yeah. In a sense, they're uncontrolled blood pressure patients and we know that this is a large proportion of patients out there. Some estimates are 40% of patients out there with hypertension that's diagnosed. These patients typically could either be on 1 or 2 medicines and still be uncontrolled or on no medicines but previously treated still uncontrolled. 

Dr Weber: So they were randomized to obviously intervention compared with sham. When was the primary endpoint of the study? 

Dr Kirtane: We ascertained the blood pressure reduction at 2 months. These patients though had to have elevated blood pressures that were maintained that way after all medicines were removed. So there was a baseline of no medications in each arm. Obviously, if patients went too high, they could be rescued and they wouldn't be then randomized. But for those patients that were able to tolerate this, and for a 3-month interval, they're able to tolerate this, many patients, we then randomized them. We followed them for 2 months after that. And, remember, the patients didn't know what therapy they had received. 

Dr Weber: Right. 

Dr Kirtane: The treating physicians in the clinic did not know what therapy they had received and they followed these patients and then measured their blood pressures with an ambulatory home blood pressure monitoring device at 2 months. 

Dr Weber: And the results, just in a nutshell, what did we find in RADIANCE II? 

Dr Kirtane: Well, the primary endpoint essentially showed that with RDN, there was a reduction in blood pressure of 7.9 mmHg. The sham group, as expected, had minimal change in blood pressure and, as a result, the difference across both arms was 6.3 mmHg, which in some respects is remarkable because in RADIANCE-HTN SOLO, the difference between the 2 arms was 6.3 mmHg. 

Dr Weber: Wow. That's wonderful to have that kind of consistency. And talking of 6.3 mmHg, are we talking about daytime? Nighttime? What exactly is the parameter we're looking at? 

Dr Kirtane: So this is daytime ambulatory systolic blood pressure (ABP), but I want to emphasize that so many people in this space, and we've learned so much over the years, fixate on the number. What's the reduction? What is it, one therapy versus the other? And, remember, it's a population and it's the mean of a population. So there's some patients that have a greater response than that. Some patients that have a lesser response to that. 

Dr Weber: Very good, yes. 

Dr Kirtane: One of the key slides I think that we've worked hard to construct in time for the presentation was to illustrate that the reductions in blood pressure were greater in patients who started off higher. And for those patients who started off lower, closer to 135 mmHg, because you did have to have that to get in the trial, the reductions were a little bit less. And so there's a gradient of effect, in a sense. And that's reassuring because if you're a clinician and you start off with somebody with a blood pressure of 170 mmHg, it'd be nice that the reduction were greater. And in this case it was almost 10 mmHg with daytime ABP. 

Dr Weber: But the great thing about RDN, and we've seen it now with the long-term follow up of the original SOLO cohort and with other studies in RDN, including other methods of denervation, this works 24 hours a day and it works 7 days a week, and as far as we know we've got some data that goes out for 3 years now, especially from the original SOLO trial. So, in a sense, this is the gift that keeps on giving, isn't it? It's as if you've given the patient a permanent reduction in blood pressure that's going to persist perhaps for years and years. 

Dr Kirtane: And certainly, in RADIANCE II, we showed the ABP monitoring curves and you can appreciate that throughout the 24-hour circadian cycle there's a reduction in blood pressure, such that daytime is reduced, nighttime isolated is reduced, and, therefore, 24-hour is also reduced to a greater extent with denervation compared to sham. 

Dr Weber: Ajay, RADIANCE II ... clearly, a big landmark as it's a pivotal trial, but what's next on the agenda? 

Dr Kirtane: Well, several things. I think, number one, we want to emphasize that we need longer-term follow-up for safety because in this trial specifically there were no adverse safety events that were observed, either changes in renal function or the other pre-specified endpoints. We want to confirm that. And that was one of the reasons why there was 2:1 randomization to get more patients treated with this device to get the experience of that.  

There are continued access registries. Some of these are led by Professor Fisher, myself, and others, you're obviously very involved in this, to treat more patients with difficult-to-treat blood pressure and to see how they respond over time. We do need to get device approval. I think that with this study we hopefully have enough data to be able to achieve that. 

Dr Weber: Right. Congratulations on a very outstanding outcome for the RADIANCE II trial and let's hope we continue to see more of these important trials being conducted. 

Dr Kirtane: Thanks and congratulations to you, too. Because, as you know, we've been through this for a long time and some of the contributions in terms of trial design, we're truly a team effort. It was really a group of people working together, trying to solve problems, and for many of us this makes this a great day. 

Dr Weber: Great. Thank you, Ajay. Great having you on the program. 

Chapter 3: Uncontrolled Hypertension: When and Whom to Refer

Michael A. Weber, MD: So we've been talking about the use of ultrasound, RDN and we've talked about some of the main studies, the RADIANCE trials, the TRIO study, and we've explored how efficacious RDN can be in many patients. I'm now joined by Dr Naomi Fisher to talk about when and whom to refer for RDN. Welcome, Naomi.  

First of all, what is the broad picture of hypertension right now in the United States? 

Naomi D. Fisher, MD: If I have to paint a picture right now, the colors that I'm choosing are browns and blacks. We're unfortunately not in a great position. There was excitement in the early part of this century with a rise in control rates, as you know, that approached 45%, even 50% and then a tapering off and over the past several years, we've stagnated and even fell. So this is not just the US, but rates are falling around the world. Even worse control in areas that have less economic fortune than the US and then Western countries. So we have a lot of work to do. 

  Dr Weber: Yes, indeed. And if we look for the reasons for poor control, it's not any particular person's fault, it's all of our faults. Patients not taking the medicines we prescribe for them a lot of the time and doctors who ought to be prescribing more aggressively, not really following through on recommendations. 

  Dr Fisher: It's interesting. You would think hypertension is simple. It's really hard. It's really hard. I think if it were easier, we wouldn't have our dismal control rates. And by the way, to put a number on it, we were maybe about 40% several years ago using the old criterion of 140/90 mmHg. But if you look at the control, which we know we should obtain, right, 130/80 mmHg, we're in the 20s (%) control rate in the US. So it's really quite dismal. 

So I think it's instructive and valuable to figure out exactly why it is so hard to take care of patients with high blood pressure. First of all, it's a chronic disease that affects millions of patients. So we've got a vast population to take care of. The population has poor lifestyle habits that are only getting worse, where more overweight, salt excess, alcohol excess stress, sedentary lifestyle. 

Hypertension is an asymptomatic syndrome, asymptomatic disease. So we know we'd all be a lot better off. It would be so much easier if a patient came in and the blood pressure of 150/100 mmHg meant their back would start hurting, or they would have a chronic cough that they couldn't get rid of. But it's not the case. So patients ignore their disease. You mentioned nonadherence, can't underestimate it. Fifty percent of patients aren't taking their pills a year out. It's half of our patients aren't taking their medications and a whole host of reasons -- cost, fear, misunderstanding, trust. 

Dr Weber: Yes, I know we used to blame that medicines cost too much, but even in health plans where you get your medicines free of charge, you still don't get good outcomes. 

Dr Fisher: Right. I think cost still plays a role, but less of a role. There's no reason for us to be prescribing anything but generic medications these days and medications that last the full 24 hours, once a day drug. But patients have, even if patients pay $10 a month for each pill and they're taking 5 pills just for their blood pressure, maybe there's 5 more for their diabetes and then for their depression. So it can add up. 

Dr Weber: Well, with all of that, when a new treatment comes along, we'd all say, "Oh, this could be great. This could be a solution." Particularly something like RDN, because once you've done it, it's there, right? You don't need anyone to take a pill. You don't need anyone to do anything proactive. It's there and, presumably, for a long time. 

Dr Fisher: And day and night, right? So we've shown that it's there. So if you take a pill, even if you take your pills, a morning pill, it's supposed to last 24 hours.  

Well, by the early morning hours, when patients are so at risk for stroke or heart attack, the pill effect may have worn off. So you add that in.  

Dr Weber: No, no. I love that thought, because if you think about RDN reduces sympathetic activity, we can reduce sympathetic activity with medicines, but very often with side effects. Here, we get it symptom-free. So another benefit, but surely there have to be some limitation on the use of RDN it's going to cost obviously, it's going to cost money. How do we decide who is the best candidate? 

Dr Fisher: We're going to be grappling with that question in a very real way now, which I think implementation is on the doorstep, really on the horizon. Patients that have severe high blood pressure, probably increased cardiovascular risk -- so stage II hypertension, blood pressure is 160 mmHg, 170 mmHg, 180 mmHg, histories of stroke and heart attack. That's the perfect person to start. There are other patients who are uncontrolled, who can't take their medications or who won't take their medications, who just simply aren't taking their medications. And I think they need to be folded in the mix. What do you think? 

Dr Weber: Now, that's exactly what worries me that as you pointed out, half of our patients don't even take whatever it is that we prescribe for them. And it's so easy to say, "It's their problem, it's their fault." But we can't think like that. Medicine is not based on that kind of ethic. We have to do whatever we can to bring their blood pressure down to a safer level. And as far as I'm concerned, if after weeks or months of trying hard to control someone's blood pressure with medications and we still haven't got near where we need to get, then we have to start talking about RDN. 

Dr Fisher: We have to talk with them and you're right. I envision this as a communication and a project together. It's not my job or my patient's job. It's our job. We work together as a team to try and get the blood pressure down and we have an option to investigate and the patient preference and what the patient thinks about is a really important consideration. 

Dr Weber: Naomi, now I can't let you escape without asking a very quick question parallel to this discussion. I know you have a very innovative program at Harvard, where you actually treat people in a sense remotely through surrogates, so to speak. Just give a very quick glimpse of that. 

Dr Fisher: So we have developed an entirely remote management program for hypertension, which preceded COVID-19 by the way. It's turned out to be a boon for patients who don't want to leave their homes now, but we've really turned the traditional model of hypertension management on its head. So instead of 1 doctor coming in, a patient takes a half a day off of work, comes in to see the doctor waits for 2 hours, pays for parking, has one blood pressure measured that's high because of white coat hypertension. 

We want to exclude white coat hypertension, and we want to exclude secondary causes while I'm at it. So this traditional model is faulty. We're not using blood pressures that matter the most. So in our program, patients are given a blood pressure cuff. They put it on, they measure their blood pressure according to AHA/ACC guidelines, which is to measure it for a week at a time, twice in the morning and twice in the evening before meds. And the blood pressures automatically and seamlessly appear. And we have, as you say, non-licensed personnel, non-licensed providers, patient navigators, we call them, could use community health workers. Dozens of them can take care of panels of thousands of patients. They look at the blood pressure averages. We have an algorithm that says not quite at goal, here's what you're on now, here's your next step.

Dr Weber: Well, that's fantastic. And I very much hope that sort of thinking pervades the community at large and we can get to that. So back to RDN, if I'm a practitioner out in the community, I've got a patient, I'm totally frustrated. I really need help. I really think that RDN is the answer for my patient. How will I get that patient to the right place? 

Dr Fisher: We need to work on the referral patterns and build it up. And it's all starting with education. So I love this program right now that we're involved in here, because we've got to educate providers. We've got to educate ourselves. We've got to educate patients and we have to build networks. Clearly, there aren't enough hypertension specialists in the country to take care of the hundred million patients with high blood pressure. 

  So it can't depend on you getting referred to a hypertension specialist. Most of the patients with hypertension are coming from primary care practices or nurse practitioners. We have to make it very, very simple for them. I can envision a checklist where they have a list of potential indications. Here's how you denied a patient and here's where you go with it. We have to simplify it, educate and simplify. 

Dr Weber: Perfect. I agree totally. We can't depend on hypertension specialists or hypertension centers. We're going to have to train a lot of people out in the community to be thoughtful and responsible referrers. 

Dr Fisher: Absolutely. 

Dr Weber: Naomi, a real delight talking to you.  

Dr Fisher: Yeah, always is. 

Dr Weber: Thank you so much for joining us. 

Dr Fisher: Thank you. Thanks, Michael. 

Chapter 4: Patient Perspectives on Blood Pressure Management

Michael A. Weber, MD: My pleasure now to welcome, Dr. Michael Bloch, a very experienced hypertension expert, who's been a big part of the development of RDN for treating hypertension. Michael, you have a lot of patient contact. You have a busy practice. What is it that is motivating patients or will be motivating patients to consider having RDN? 

Michael J. Bloch, MD, FACP, FASH, FNLA, FSVM: Well, I think patient preference is going to be incredibly important in moving this technology forward. And I've been really surprised both in my own practice of recruiting patients for clinical trials, as well as in some of the research that's been done around patient preference, about just how wide an audience is interested in RDN. When you ask patients whether they would rather take another medicine or potentially get RDN, in the setting of poorly controlled high blood pressure. Usually, most of these surveys suggest that somewhere between about 30% and 50% of them would consider RDN.   

Dr Weber: One of the fascinating things we've learned from some of the surveys that have been done and from other sources as well, is that probably the biggest explanation for poor blood pressure control is the failure of patients to take medications. In other words, poor adherence. Now I will immediately acknowledge, but big part of not getting good blood pressure control is often that physicians are not as aggressive as they should be in writing prescriptions and in encouraging people to take meds ... But there is a paradox isn't there? We have patients who worry that pressure is high. They know they could be at risk of a stroke or a heart attack, yet they're not all that reliable in taking the medications. Have you ever been able to understand that? For me, it's very mystifying. 

Dr Bloch: Yeah. For these surveys, it has helped me understand that a little bit better. I've always wondered why it was, why don't they care about their blood pressure? Why don't these folks with uncontrolled high blood pressure want to get it down? And what I think that these surveys, and there're a lot of different surveys, and this is talking about them generally, an aggregate.  

Interestingly it does appear that patients really do want their blood pressure down. Sometimes we don't realize it, but they do. If you ask them, they want their blood pressure down, they just don't necessarily want to take another medication. And they are willing, in fact, to accept fairly high side effect ratios, higher than we've seen in our clinical trials ... and fairly modest gains in blood pressure, less than we've seen in our clinical trials in order to have that procedure and get their blood pressure down. It's just, I think we've always underestimated how much patients don't like taking a pill, or at least some patients, don't like taking a pill every morning.   

And these surveys are done in a really interesting way. Generally, what we're asking is would you take another pill? Because that's really the clinical question, right? It's not, "Hey, do you want to have this procedure?" It's, "All right your blood pressure's not controlled. Which would you rather do -- take another pill or perhaps, have this procedure?" And it's in that scenario that patients are saying, "I'd rather at least consider this investigational device that we don't know very much about. And it has a risk of side effects rather than take another pill. I really don't want to take another pill." 

Dr Weber: No, that's really very interesting. And I suppose we've slowly learned that lesson over the years. But when we think about RDN, it is a procedure, and there's going to be some need to be selective in how we choose patients who, perhaps, are the most eligible to have this intervention. What are some of the minimum requirements, Michael, that you would want to impose before you would say to a patient, "Would you like to be considered for RDN?" 

Dr Bloch: Oh, it's interesting. So some of these actually come out of the same surveys that look not just at patients, but also at providers. And one of the things that providers tell you, is that they are only willing to do an intervention like this if they have a patient who has poorly controlled blood pressure; if they're going to think they're going to get a significant reduction in blood pressure; if they've confirmed the blood pressure is high out of the office before providing this procedure; have a low risk of side effects; and importantly, they also want to make sure that there is high cardiovascular risk in these patients. I think most providers and, I think this has come through in most of our guidelines, really want to have at least some degree of a measurement of cardiovascular risk and absolute benefit in these patients. 

Personally, I don't believe that all of these patients need to have resistant hypertension. There're a lot of patients on 0, 1, and 2 medicines who have poor blood pressure control and are unwilling or unable to take another anti-hypertensive medication. I think this is a great procedure for them. I think we just want to make sure that the cardiovascular risk is high enough to warrant a potentially expensive procedure. And then that blood pressure elevation is confirmed out of the office. 

Dr Weber: Well, of course, with a population that seems to be getting progressively older and progressively more obese, there will be plenty of people at relatively high risk who would be eligible for this procedure. And it's going to be fascinating to see how it all plays out once these procedures become available. 

Dr Bloch: I think that's absolutely right. But I think that that's why our guidelines, the guidelines that have come out or the statements that have come out such as the one from the National Kidney Foundation and SCAI, really speak so much about patient preference -- has to be a big piece of the puzzle. How are we going to whittle down that huge funnel of uncontrolled high blood pressure? We really want to be doing it for patients who'd rather do it than take a medicine. And I think we do need multidisciplinary teams of providers who seem to really understand the question that's being asked. Is this a good candidate for RDN, as opposed to medications? So a patient who's activated and well-informed meeting with a set of providers who are also well informed and well intentioned. That's where I think we're going to get our best clinical decisions, not just really for hypertension, but in general. 

Dr Weber: Well, thank you, Michael. Very illuminating talking to you and I very much appreciate your insights into this matter.  

During the course of our program, we've had the opportunity of considering a number of issues. And again, I'd like to thank Dr Azizi and Dr Kirtane for their insights unto the status of RDN. At the current time, it is not yet approved for use in the United States. It's still investigational, but probably going to be available relatively soon. So it's soon going to be a real issue and a real choice that we and our patients are going to have to make. And we heard about the progress of the clinical trials using either ultrasound, as the means for causing denervation of the kidneys or radiofrequency ablation. Those are the two techniques currently most far along in terms of development. There may be some other techniques lagging a little bit behind, but could also be very effective and well worth considering.  

We had a wonderful input from Dr Naomi Fisher, who just made the point that fewer than half of our patients with hypertension had their blood pressures under control. It's really lamentable that with so many medicines available, we as a community, have not done a good job in managing hypertension. Some of the blame’s on us as physicians, that we've not been as aggressive and assertive as we should be in managing hypertension. 

But there is this huge problem, as Dr Bloch has pointed out to us of patients not being adherent, not wanting to take more pills. Hypertension, after all, is an asymptomatic condition. You don't have a pain or some other distressing symptom that's going to compel you to say, "Oh, I better keep taking my medications." So, a real issue.  

And of course, RDN working 24 hours a day, seven days a week ... and as we heard from Dr Azizi working for 2, 3 years, at least -- so a really nifty solution to patients who are not doing well on medications, whatever that reason might be. 

So an exciting area, I look forward to further developments over the next few months. Once again, my thanks to Dr Michael Bloch and our other colleagues for participating in this program. And of course, my thanks to those of you who are watching. I think it's very important that you be kept up to date with these developments.

I hope you'll answer the questions that will now follow and give us a good evaluation of what we have been discussing in this program today. Thank you very much for being part of this important program. 

This transcript has not been copyedited

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