BACKGROUND:  High blood pressure is a serious condition that can lead to stroke, kidney failure, heart failure, coronary heart disease, and many other health problems.  Blood pressure is the tension of blood pushing against the walls of the arteries as the heart pumps blood.  One in three adults in the United States has high blood pressure.  People can have it for years and not even know it.  However, through time it can damage the heart, kidneys, blood vessels, and other parts of the body.  (Source: www.nhlbi.nih.gov)

 

BLOOD PRESSURE NUMBERS:  Blood pressure is measured as diastolic and systolic.  Diastolic refers to blood pressure when the heart is at rest between beats.  Systolic is when the heart beats while pumping blood.  More commonly, blood pressure numbers are written with the systolic number before or above the diastolic number, like 120/80 mmHg.  Normal blood pressure levels in adults are 120/80.  Prehypertension levels are 120-139/80-89. High blood pressure in stage 1 can range from 140-159/90-99.  High blood pressure in stage 2 can range from 160 or higher/100 or higher. Blood pressure levels are usually not consistent.  It can lower while sleeping and rise when awaking.  It can rise from being excited, active, or nervous.  If numbers stay in the prehypertension level, then the risk of developing high blood pressure increases.  (Source: www.nhlbi.nih.gov)

 

NEW TECHNOLOGY:  People who have high blood pressure can take steps to control it and reduce the risk for other health problems.  Lifestyle changes go a long way when controlling high blood pressure, but sometimes that’s not enough. Medications are generally prescribed by doctors to lower it, but depending on the stage and the patient’s general health medications may not be an option.  One of the body’s methods for controlling blood pressure involves the sympathetic nervous system.  It includes the major organs responsible for regulating blood pressure.  The kidney plays a major role in regulating blood pressure.  Renal nerves communicate information from the kidney to the brain.  People with hypertension have hyperactive renal nerves, which raises blood pressure.  Renal Denervation treatment is in clinical trials to learn whether renal denervation is safe and effective.  The Simplicity HTN-3 clinical trial will attempt to disrupt the hyperactive nerves by applying radio frequency energy near the nerves with an experimental medical device.  A single procedure inserts a tube in the groin and places the device in the artery leading to the kidney.  Multiple treatments are performed in each artery to disrupt the hyperactive nerves.  After treatment, the device is removed.  To find out if you are a candidate for this trial, visit http://www.symplifybptrial.com/candidate/ to take a short survey.  (Source: http://www.symplifybptrial.com/therapy/)

 

David Brown, MD, Interventional Cardiologist at The Heart Hospital, talks about a new way to treat high blood pressure.

How many people in the world are affected by hypertension?

Dr. Brown: There are a billion people in the world that have hypertension, high blood pressure that is not controlled. By 2025, there will be 1.6 billion people with hypertension. One-third of them are treated and not controlled with resistant hypertension and another third are untreated.

What does that mean? Are the numbers going to skyrocket with people having heart attacks and strokes?

Dr. Brown: Absolutely. For every 10 mmHg of blood pressure increase, the number of heart attacks doubles and strokes double.  For every reduction of 2 mmHg, there is a decrease in strokes by 10%.

Until now, was it kind of a hopeless feeling for you when you had someone who did not respond to medication?

Dr. Brown: Interestingly enough, it really wasn’t hopeless to physicians. If we go out and survey physicians right now every one of us will tell you, “Oh, I treat high blood pressure. I treat it really well. I am the best doctor treating high blood pressure.” It turns out; your patients still have high blood pressure. We found that out by doing this trial and looking at this treatment we are going to talk about. Because if you ask me, I would say “Oh, no, I have got this covered. I know how to treat blood pressure. I got my patients on the right medicines.” However, sometimes they do not take it; sometimes they are allergic to it; sometimes they are just aggravated about it and do not do it; and other times they are missing when their blood pressure is too high. So, we really have not controlled the blood pressure very well at all; even though we thought we did and even though we say we do.

What is the theory behind renal denervation? 

Dr. Brown: This is the first change in 100 years in the treatment of high blood pressure. I mean this is a disruptive technology. This is something that really changes the face of treatment of the disease. We have learned a long time ago that if you change some of the patterns of nerve information sending in the body, we can alter some of the metabolic processes and one of them is how blood pressure is controlled. We have used medicines to do it, but all the medicines have side effects. We see these patients who require 1, 2, 3, 4 or 5 medicines. They require maximum doses of medicines while not feeling well. So, the issue is with renal denervation, we thought if we can change that by having a treatment that brings blood pressure down significantly, then we might be able to remove some of those medicines; maybe even get off medicines all together.

This specifically targets the pathways from which organ?

Dr. Brown: This is primarily brain and kidney nerve flow and nerve impulses go both ways; some from the kidney feed to the brain, the brain back to the kidney, and the brain to the kidney. It is the part that controls what happens to sodium retention, your volume, and blood pressure. The kidney sends signals to the brain telling it what is going on and what to do. If those signals ramp it up too much and the result is hypertension, all kind of bad things happen.

How often have you done this procedure?

Dr. Brown: We have only done about 13 of these procedures.

Can you explain exactly how you do it? 

Dr. Brown: People are familiar with heart catheterization, but that is when we want to go look at things in the heart. We go look at arteries and look at blood flow. We do that by usually going through the groin or we can go through the radial artery.  It is under local anesthetic; the patient is awake. It is a small needle stick to get into the bloodstream. Well, this new procedure is the same thing. This is kind of like angiograms. So, we put a needle in the femoral artery in your groin. Once we get in there, we can put wires, catheters, balloons, and all sorts of devices in there. We go up and we take some pictures of the kidney arteries. It tells us the size of the arteries, where they branch and what they look like. Basically, we are looking to guarantee the safety of a procedure by following those pictures with an electrode-tipped catheter. It is basically a catheter with electricity where we can put it in the right spot in the artery and we are going to with low radiofrequency transmission, burn the nerves, and ablate them or knock them out. If we do that, we can change some of that feedback that is going on between the brain.

Is it that you are blowing out or not going to burn anything that is important?

Dr. Brown: This was discovered not quite three-quarters of a century ago. In the 1940’s and 50’s, this was done by surgeons whenever it was discovered that this could really have a big impact on decreasing this sympathetic nerve overdrive system. They went in and did it surgically. The problem was with surgery. They had all sorts of other complications. Now, we have a direct and easy way to get there and not harm any other organs and not hurt the kidney. With low frequency electricity, we can actually ablate that nerve. It is like cutting a wire. Once we do that, we can stop a lot of these bad impulses going back and forth.

There are so many wires in a car because all those wires go someplace and serve a purpose; does this not serve a purpose for anything? 

Dr. Brown: It does. It serves the purpose of conducting those nerve impulses that we talked about that go back and forth to the brain. However, what has happened is basically some evolution. We needed this nerve overstimulation or this sympathetic drive, sort of like the fight or flight adrenaline syndrome. Now, interestingly enough, it can still do that even after we ablate these nerves because you have plenty left and we many only reduce it by 20%, but we do not need those times and events anymore. The effect that it has on you and human life and what you do, is nonexistent. I mean you really cannot measure any difference and what you can do about all that.