Denervation can lower blood pressure for some patients

[00:00:00] Host Amber Smith: Upstate Medical University in Syracuse, New York invites you to be "The Informed Patient" with the podcast that features experts from Central New York's only academic medical center. I'm your host, Amber Smith. High blood pressure can lead to stroke, heart attack, kidney damage, and other problems. Many people struggle to control their high blood pressure with lifestyle modifications and medications. They have what's known as resistant hypertension. An endovascular surgeon at Upstate now offers a procedure to help lower high blood pressure. Dr. Wei Li is an associate professor of surgery at Upstate, and he's here to tell us about renal denervation. Welcome back to "The Informed Patient," Dr. Li.

[00:00:44] Wei Li, MD: Thank you Amber. Thank you for the nice introduction.

[00:00:47] Host Amber Smith: Well, let's start with a description of what blood pressure is and why it's an important measure of our health. What is a healthy blood pressure number?

[00:00:57] Wei Li, MD: The healthy blood pressure numbers in the United States, according to the national guidelines, are anything above 130 over 80 are considered hypertension. And according to many studies in the nation, one in two Americans suffer hypertension in our lifetime.

[00:01:18] Host Amber Smith: So the blood pressure reading, does this kind of tell us how well our arteries are working? Is that what we use it for?

[00:01:25] Wei Li, MD: That's correct. Not only tell us how well our arteries system is working, also tell us how much blood flow and if there's any potential damage to our end organs -- meaning brain, heart, kidneys -- can benefit or can be harmed by the blood flow perfusion. If the blood pressure too high, will damage our heart and the brain, kidney, and even more. With hypertension, certain patients unfortunately cause mortality as a result of heart failure or stroke. Some of them are related to hypertension.

[00:02:04] Host Amber Smith: So why do some people get high blood pressure or hypertension? What causes that?

[00:02:11] Wei Li, MD: It's a long story. Hypertension can be causedwith many, many reasons. And there are two different categories. One is primary hypertension, which I think majority of hypertension patients belong to that category. The second one we call secondary hypertension. Very few people statistically belong to that category.

I think this today's topic, we mainly talk about primary hypertension that could be potentially treated with renal denervation, which is a new technology the US FDA (Food and Drug Administration) approved recently in November last year.

[00:02:53] Host Amber Smith: So that is for people whose hypertension is uncontrolled with multiple medications and with multiple lifestyle modifications.

[00:03:02] Wei Li, MD: Mm-hmm.

[00:03:02] Host Amber Smith: They still have high blood pressure. And so now the FDA has approved this new procedure. What can you tell us about it? What's it called, and how does it work?

[00:03:11] Wei Li, MD: This new procedure actually started around eight, seven years ago. And the current device are second generations, and their two manufacturers make this device. The current generation, according to the FDA clinical trial, both devices can on average lower the blood pressure, systolic blood pressure, we call SBP, by 10 millimeters of mercury. As background information in a big journal, notable to any medical professionals, published in 2016, a reduction of 10 millimeters of mercury in systolic blood pressure is associated with substantial or significant risk reductions. For example, 28% reduction in heart failure, 27% reduction for stroke, 17% for coronary disease, meaning heart vessel disease, and 5% for chronic kidney failure. And the most important thing is the 13% reduction for mortality by even as little as 10 millimeters of mercury, 10 point of blood pressure drop in SBP, we call systolic blood pressure. So that's the benefit, and the very significant benefit, that could potentially offer by these two newer generation of renal innovation devices.

[00:04:39] Host Amber Smith: Those numbers do sound significant. How safe is the procedure? And, are there any risks?

[00:04:46] Wei Li, MD: Like any other newer minimally invasive procedure, they all have a risk. However, the benefit at the current time, based on the clinical trial and also my personal experience, the benefit outweighs the risks. However, we always consider risk for any procedure, even for a small procedure like hernia repair, gallbladder removal, they all have a risk.

But I think for this particular procedure, is generally speaking, considered low risk procedure, can be done with local anesthesia, moderate sedation without going to the operating room. And we can do what we call in the "cath lab," (catheterization lab) and patient come in the same day in the morning and then finish the procedure and then to be discharged on the same day.

[00:05:33] Host Amber Smith: So, Dr. Li, I understand you're the principal investigator of studies for Recor Medical, the maker of this renal denervation device. What does that role involve?

[00:05:45] Wei Li, MD: That role involves actually a post-market study. The study is considered to get the real world experience after the FDA approved the devices and I was selected as a PI (principal investigator) for this study. And actually for this year, the study organizer only picked about 30 PIs or institutions to be part of the study. And I was honored to be selected as the only vascular surgeon PI among this 30 PIs in this study. And of course, Upstate is one of the 30 sites, first batch of the 30 sites.

And to be in this study, that means what? Meaning we are able to offer the, not only the commercial use of the device to treat non-controlled hypertension or resistant hypertension. Also as an institution, as my study group, we'll be able to contribute the real world experience in terms of this study. This is significantly important compared to the pre-approval study population because this is a real world experience on the general public.

[00:06:59] Host Amber Smith: So that's really an important role to be a principal investigator for anything, but for this in particular. So can you walk us through what patients will experience? How would a person be determined to be a candidate for this procedure?

[00:07:15] Wei Li, MD: There are three different indication or criteria for patient to be selected, to be indicated for this procedure. And the first one will be patient on three blood pressure medications with maximum dose they can tolerate and still cannot meet the goal of blood pressure of 130 over 80.

And the second group of patients who are indicated (for the) procedure are the ones, the patient, for whatever reason, they cannot have a good compliance with the medication they were given. For example, maybe because of the side effects, maybe because the patient's personal reasons. For example, frequent travelers cannot take the water pills every day, for example, because if that's the case, they have to go to the bathroom frequently, right? Then some of them in the second group, a lot of them are working group, working age group patients. They cannot tolerate the side effect. And then at the end of the day, between the work and life, they end up with uncontrolled hypertension.

The third one the group for the patients who have non-controlled hypertension above 130 over 80. And those group patients already suffer the complications from their hypertension. For example, they already had stroke, they already had heart attack, already have kidney issues. But luckily they still can survive at this time.

But I think the renal denervation offers a good adjunct treatment for all three groups, in addition to the blood pressure medications. I want to make it clear, the renal denervation procedure is not designed as a sole treatment for hypertension. They are designed as adjunct treatment, which is the first ever minimally invasive treatment hypertension, in addition to conventional, traditional medication. Most of them are pills.

[00:09:14] Host Amber Smith: So the patient may still require some medications, is what you're saying, after the procedure.

[00:09:21] Wei Li, MD: Yes, that's exactly correct. For example, my first patient was on four medications, still couldn't get control, and my first time I saw him, I remember his blood pressure was 190 over 89. The second time I saw him, the blood pressure was 180 over 86. That was about four months apart. And he was very actively involved with his cardiologist, general cardiologist, to get pressure control, but was not able to over four months. And then at the same time, he had another aortic pathology, which gave him additional risk factor in terms if the blood pressure not controlled.

So after procedure, he was normotensive, blood pressure about 120 over 70. As a result, I actively reached out with his cardiologist, even from day zero on the same day of the surgery, to coordinate the care. And at the current time he not only reduced the from four to two medications, but even the two medication he has right now, I was told by him and the family and his cardiologist, those two medications, now he's taking with reduced dose.

We all know the less medication, the less side effect; and the lower dose, the better in terms of not only side effect and also overall given the magnitude of hypertension. And if you take the population as a whole, that procedure itself will offset some of the healthcare expenditures for the long run.

[00:11:00] Host Amber Smith: This is Upstate's "The Informed Patient" podcast. I'm your host, Amber Smith. I'm talking with Dr. Wei Li. He's an associate professor of surgery at Upstate, and he's the first vascular surgeon, not just in upstate New York, but globally to perform the ultrasound renal denervation on a patient after the FDA approval.

So patients who have uncontrolled high blood pressure, they may be referred to you by their primary care doctor or their nephrologist or a cardiologist. And then they come to you, and once you determine that they're a good candidate for this procedure, and they decide they want to do it, can you walk us through how it's actually done?

[00:11:40] Wei Li, MD: We give the patient the material about the procedure. We have a very detailed, we call in medicine or surgery we call "informed consent," with heavy involvement of the patient, not only patient, but also family because they need to understand what the procedure is. Because this group of patients, a lot of them are relatively healthy. We make sure they understand the risk benefit.

And once the patient understand the procedure, once we determine the patient's a good fit for the procedure, then we start planning.

[00:12:14] Host Amber Smith: So the procedure takes about an hour. It takes place in the hospital. Is the patient awake for this, or are they under anesthesia?

[00:12:23] Wei Li, MD: Patient is awake, and I can have the conversation with the patient because sometime ask the patient: hold breathing, breathe in and out, and then relaxing. In the procedure, of course we give local anesthesia just like we go to the dental office, right? We can inject local anesthesia to make a patient more comfortable. We give something called moderate sedation, meaning patient is not asleep, but we give some medicine to make patient comfortable as much as possible remove their anxiety, for example.

At the same time, they are alert. They can have a conversation with the providers.

It's considered outpatient procedure. The patient is admitted in the morning and discharged after the procedure, in this case early in the afternoon.

[00:13:09] Host Amber Smith: Now you said it's minimally invasive. So where is the, it's a single incision that you make, is that right?

[00:13:15] Wei Li, MD: I would say you can call it single incision, but it's mostly a needle hole. It's about 1.5 millimeters on the skin and then require no, or almost no stitches.And the patient walk out the hospital on the same day, walking around at the same day.

[00:13:35] Host Amber Smith: So you need that so that you can access the artery.

[00:13:39] Wei Li, MD: Yes.

[00:13:39] Host Amber Smith: And then you insert something that goes, how far? How far down the artery do you go before you -- because that's how you apply the ultrasound through this, this probe or something, right?

[00:13:51] Wei Li, MD: Actually we use ultrasound for different means. At first we use ultrasound guidance to access the arteries, so we make sure it's minimally invasive. We use a needle at the groin area, only one groin, not two. How far it goes: the catheter wire system go up, from the groin to the kidney level to the aorta and around the renal artery. And then we put the catheter system into the renal artery with a careful maneuver.

We advance the catheter with a balloon into the renal artery, and we utilize ultrasound as energy. And the energy, this is what they call renal ultrasound based renal denervation. We use ultrasound as the energy to basically ablate or kind of block the nerve surrounding the renal artery, because the nerves surrounding the renal artery are the ones to mediate blood pressure change. Because a patient with uncontrolled hypertension, somehow the activity of those nerves surrounding renal artery have a higher than average activity so we try to decrease the activity of those nerves to block the pathway of hypertension, the circuit.

So this was done through energy from the ultrasound. And then of course we use the balloon filled with the water because ultrasound transfuses or travel better through the water. The nerve around the renal artery can be treated, and as a result, lower the blood pressure.

[00:15:35] Host Amber Smith: So even though the patient has some conscious sedation, can they feel when you're doing this? Can they tell that you're near their kidney when you're doing the work?

[00:15:45] Wei Li, MD: Most people don't feel too much. I think small proportion, and my patient, did not feel at all. But according to the pre FDA approval study, some patients feel some pain in the back. That's why we need good coordination, as a team, with our nurses, at the bedside and during the procedure, to give the medication in advance before we trigger the ultrasound energy to treat the nerve. It's individually different. It varies from patient to patient, but overall it should be tolerable. It should not require major medication for pain.

I alert the patient before I start the treatment, because it requires three activations of ultrasound energy deliveries for each artery. So totally together is about six treatments, less than 10 seconds for each treatment and total together 60 seconds or less.

With the trained individual practitioners, and I think this is a good adjunct treatment with minimally invasive technology to treat uncontrolled hypertension, which is a disease over 100 years, were treated with pills only.

[00:16:53] Host Amber Smith: So how soon after this procedure does the blood pressure lower?

[00:16:59] Wei Li, MD: It varies from individual to individual. For this particular patient, the pressure drop on the table, to normal pressure from 170 over 80, all the way down to 120 over 70. Individual response is different from patient to patient. So that's why that requires a lot of coordination among care providers. Depending the level of responsiveness on the patient, we address medication accordingly.

For the long term most patient can maintain more than 10 points of blood pressure decrease over long term. After procedure, the pressure as a human body because the body try to repair and try to reset back to their status from before the operation, before the procedure. We may expect some of this patient blood pressure may slowly back up a little bit, right? But I think based on the study we have, prior to FDA approval, the study still suggested that the long term blood pressure reduction is still there. And as a result, we'll significantly reduce the complications from the hypertension.

[00:18:05] Host Amber Smith: Do we know how long the denervation will last? Will those nerves kind of re-nervate?

[00:18:13] Wei Li, MD: So at this time, based on the study, the FDA indication and suggestions are we only do one time per patient lifetime for renal denervation.

Then that means based on all the study published from the clinical trial prior to FDA approval for both devices, actually, the FDA does not suggest doing a second time renal denervation with either devices. That's based on the study we have so far. Because it's new device, less than half years old, long term, I think rely on physicians, rely on the post-market study, which I'm one PI in the nation to confirm or to revise the indication if there is a change in terms of long-term result.

[00:19:01] Host Amber Smith: I know that you said, Dr. Li, the patient may end up needing to still take their blood pressure medicine, but different dosages or fewer meds maybe. Are there other restrictions after the procedure for patients? Does this impact what they can and can't do?

[00:19:17] Wei Li, MD: For the short term, immediate after the procedure, of course, like any other procedure like hernia repair, or gallbladder removal, I always tell the patient activity as tolerated, and return to work if they're not heavy labor. If they're office worker or even moving around their house, I do not have much restrictions.

Of course, whenever a patient adjusts medications, patient need to closely watch their blood pressure, because whenever there's change on the medications, the blood pressure, the body responds differently from patient to patient. And even if the medication decreased by half, I would suggest the patient monitor their blood pressure closer than before. Maybe check the blood pressure at least once a day and then talk to the providers who gave them medication frequently in case the patient finds their blood pressure fluctuation, or decreasing or increasing.

[00:20:11] Host Amber Smith: I appreciate you making time for this interview, Dr. Li.

[00:20:15] Wei Li, MD: Thank you.

[00:20:16] Host Amber Smith: My guest has been Dr. Wei Li, an associate professor of surgery at Upstate who offers a renal denervation procedure for people with resistant hypertension. "The Informed Patient" is a podcast covering health, science and medicine, brought to you by Upstate Medical University in Syracuse, New York, and produced by Jim Howe. Find our archive of previous episodes at upstate.edu/informed. If you enjoyed this episode, please tell a friend to listen too. And you can rate and review "The Informed Patient" podcast on Spotify, Apple Podcasts, YouTube, or wherever you tune in. This is your host, Amber Smith, thanking you for listening.