Saving Charlie’s heart: Cardiac device for kids
BACKGROUND: Cardiomyopathy refers to diseases of the heart muscle. These diseases have many causes, signs and symptoms, and treatments. In cardiomyopathy, the heart muscle becomes enlarged, thick, or rigid. In rare cases, the muscle tissue in the heart is replaced with scar tissue. As cardiomyopathy worsens, the heart becomes weaker. It's less able to pump blood through the body and maintain a normal electrical rhythm. This can lead to heart failure or irregular heartbeats called arrhythmias. In turn, heart failure can cause fluid to build up in the lungs, ankles, feet, legs, or abdomen. The weakening of the heart also can cause other complications, such as heart valve problems.(Source: http://www.ncbi.nlm.nih.gov)
TAKING OVER OUR CHILDREN: Cardiomyopathy is nondiscriminatory in that it can affect any adult or child at any stage of their life. It is a particularly rare disease when diagnosed in infants and young children. Cardiomyopathy continues to be the leading reason for heart transplants in children. Currently there are no published reports specifying the total number of children affected, but it is roughly estimated to be in the hundreds of thousands when all forms of cardiomyopathy are taken into account. According to the national pediatric cardiomyopathy registry, 1 in every 100,000 children in the U.S. under the age of 18 is diagnosed with primary cardiomyopathy. (Source: Children’s Cardiomyopathy Foundation)
TREATMENT: Unfortunately, there is no current cure or treatment that can return the heart to normal or guarantee long term survival. Although occasionally children with certain types of cardiomyopathy do improve, the vast majority do not show any recovery in heart function. If detected in the earlier stages, cardiomyopathy may be controlled with long-term drug therapy and placement of a pacemaker/ defibrillator. If the cardiomyopathy is associated with electrical disturbances, heart pacemakers may be implanted to provide stable, coordinated electrical impulses to the heart muscle. If there is a potential for sudden cardiac death, an implanted defibrillator may be considered. The device can recognize ventricular fibrillation, a rhythm that does not allow the heart to contract, and deliver an electrical shock to return the heart to a coordinated stable rhythm. If indicated, there are some implanted devices that are both pacemakers and defibrillators. Severe cardiomyopathies may not be able to be controlled or treated with mediation, diet, or other surgical interventions. In this situation, heart transplantation may be a consideration as a final option. (Source: http://www.emedicinehealth.com)
NEW TECHNOLOGY:When a donor heart is not available during the end stage of heart failure, the implantation of a ventricular assist device is the only therapeutic alternative. Many such devices are designed to provide circulatory support to adults, but very few are available for children and infants, especially in the United States. In children, implantation of ventricular assist devices that are designed for adults carries a high risk of complications, because the low stroke volumes that must be used can result in inadequate pump washout and excessive thromboembolic risk. The Berlin Heart excor® Pediatric VAD is a pulsatile assist device that comprises a compressor and pumps (artificial ventricles); it is connected to the heart with cannulas. The device's pumps are designed to provide different stroke volumes: 10 mL (suitable for newborns), 25 and 30 mL (suitable for infants and children with body surface areas <1.2 m2), and 50 and 60 mL (suitable for adults and larger children). These stroke volumes in pumps designed for children of various sizes will enable proper washout of the pumps. (Source: http://www.ncbi.nlm.nih.gov)
Bob Stewart, MD, Pediatric Congenital Heart Surgeon at The Cleveland Clinic, talks about new technology that saved a little boy’s life.
Tell me a little bit about Charlie.
Dr. Stewart: Charlie is a 3-year-old boy, and right now, like most 3-year-old boys, he wants to do is play video games and pretend to be different super heroes. However, he has a serious heart condition called dilated cardiomyopathy. Dilated cardiomyopathy is a condition where his heart develops muscle cells are not normal. Charlie was diagnosed when he was 4 weeks old and since birth has been watched very carefully. A little over a year ago, he started to fail clinically. He was not able to run around and eventually it got bad enough where he was not really able to of eat.
Was he just so weak?
Dr. Stewart: He was so weak from his heart pumping so poorly and this lead to all of his life functions becoming diminished.
Is it expected?
Dr. Stewart: There is a lot of different flavors of cardiomyopathy, but it is not uncommon for patients to sort of have a heart that does not function normally, but many patients have a lot of reserve.
Is it a birth defect?
Dr. Stewart: It can be. You can be born with it, like he was. Right after birth he had an abnormal heart. Some babies need to be transplanted at birth because they never get out of infancy with the heart function they have. Charlie thrived for a while, but eventually it caught up with him. He was then evaluated and put on the transplant list at home, but his condition deteriorated. We brought him into the hospital and put him on an infusion of a medicine that helps the heart beat stronger. On this infusion, he was doing better.
Did he have to live at the hospital?
Dr. Stewart: Absolutely.
Was it a constant infusion?
Dr. Stewart: Exactly. It is a drug called Milrinone and it is used quite commonly. There are some adults who are living outside with a constant infusion of Milrinone. However with children, we keep them in the hospital once they get to that point and are waiting for a heart transplant. Despite that medicine, Charlie really did not get a lot better after a while. It was scary to see him deteriorating even with medical therapy. He was skin and bones. Despite our efforts at nutrition, he just failed because his heart wasn’t even strong enough to pump blood to his abdomen to digest food. He eventually was in constant pain from the poor blood flow to his abdominal organs. He was at a point where we thought he was in jeopardy of not surviving; we went ahead and implanted the Berlin Heart.
Is it really hard to find a heart for someone like Charlie, or a child?
Dr. Stewart: The waiting list seems to be getting longer and longer. In terms of getting a heart organ, I cannot tell you the exact statistics, but a few years ago, I knew that the waiting time was about 3-1/2 months and it has at least doubled.
If the FDA would not have approved the Berlin Heart for children in December, what would have happened to Charlie?
Dr, Stewart: We were able to get the Berlin Heart and it has been available through an exemption, but you literally have to just go through a lot of red tape. There are a lot of consent forms and you have to get letters from several physicians saying that this was a desperate measure and this was all that could be done and then you would send these in and they would literally get filed with the FDA. The equipment could not be kept in the United States, so unless they happened to have one that had been used at some other institution and it was getting sent back to Germany, you could intercept one and get one quickly, but otherwise, they literally have to fly a lot of the equipment in from overseas.
How long of wait would that be?
Dr. Stewart: A few years ago, it was up to a week and it got better and better as more people were successfully using the Berlin Heart and there were more centers and more children who were getting it. It could still be anywhere from 24 hours to 72 hours at a very critical juncture when you know somebody needs life support, it is not sort of “well, how about 3 days from now?”
What is the Berlin Heart?
Dr. Stewart: The Berlin Heart is a ventricular assist device (VAD) developed especially for children. Its function is to help the heart pump more efficiently. For adults, the technology for VADs has been around longer. There is a whole number of commercial available VADS for them. The transplant list can be so long. If you need a heart because you are not doing well, but you are not so sick that you need to be lying in a hospital bed, there is a big zone between those two. For those people is very difficult to get a heart on that list. The ventricular assist device in adults just by sheer size can be implanted inside of the body; either inside the chest cavity or in the abdomen, and connected to the heart such that you can have this exactly what the term says, ventricular assist. But with kids, even for the little small pumps, they are not really compatible with being put inside the body for the most part. The Berlin Heart mimics what we did with adults a number of years ago, where we had what we called extracorporeals, or pumps outside of the body. These cannulas are implanted in the heart then come out through the upper abdominal wall. They rest on the belly and then these things work no matter what kind of pump is used. The Berlin has a power source that is running the device which drives a pneumatic pump. There are other ones in the adult world where there is basically a screw, we call those axial pumps. As the screw turns it drives the blood along. But for kids who are under 25 kilograms (11 pounds), the Berlin Heart has been the most effective ventricular assist device. There has been a smattering of some other investigational ones, but this is the one that has been implanted in hundreds of kids in the United States, over 1000 worldwide.
Is it inside Charlie right now?
Dr. Stewart: Yes. He has a cannula that is sewn into his aorta and a cannula that is sewn right inside of his left ventricle. As blood enters his left ventricle, it should be pumped through his aorta. Instead, it is actually pulled out through that cannula that comes out of his abdomen into this chamber that squeezes. This cannula is connected to a driver that pushes air, squeezes his blood and it goes back into another cannula that returns blood back into his aorta. Essentially, this external pump takes over the function of the ventricle that is failing.
How quickly do you see a change?
Dr. Stewart: It is remarkable how his color immediately was better. His vital signs were better. Everything was better quite quickly. There is the trauma of the operation, which requires time for healing. He was awake and tolerating tube feedings within the first week. After 2 weeks he was taking small steps in his room, and within a month he was gaining weight again and taking walks all around the hospital.
How do you get him to not tug on the tubes?
Dr. Stewart: That was never an issue. Charlie learned very quicky that moving the tubes would hurt so he left them alone. We had to devise a bulky gauze dressing to support the pump and prevent the cannula from tugging on his abdomen. Coping with this new attachment to his body, and the intricate dressing changes is another story. It is very unnatural to have a giant pump coming out of you and then have something the size of a shopping cart basically that you have to push around. That is an adjustment. But, he is 3 and you get used to anything and Charlie has been very accepting of his new way of life..
Without it, would Charlie be here?
Dr. Stewart: I don’t think so. He was on a slide from just malnutrition alone. He was prone to have a serious complication and he would not, with his heart function, tolerate much of a complication. He just did not have the reserve anymore. I think he would have died. He has been on the Berlin Heart 4 months now. In fact, I almost want to say it is exactly 4 months.
When you get the Berlin Heart, does that put you at the top of the list for a transplant?
Dr. Stewart: No. It actually does not change your status in the sense that he was already on the most medical therapy that we could put you on without a device. That already puts you at the top of the list. He was a 1A. It just is a long time trying to get an appropriate size, appropriate quality heart for a little kid.
How long can he stay on this?
Dr. Stewart: Our first patient was on it for almost 9 months and did very well. In the U.S. there are reports of children being on the Berlin for up to a year. However, in Europe the longest time a patient was on the Berlin was 3 years. We worry about infection and thankfully Charlie did not have any serious infections. We also worry about neurologic complications. With your blood going through a device like this, at any time, you can get clots and they can go right up to your brain. To prevent those clots, we put you on a lot of blood thinners and those could cause serious bleeding. You are riding a fine line where you worry about a stroke from a clot or from a serious hemorrhage. He went 9 months without a stroke, which we feel good about and so far, Charlie is at 4 months without any serious complications. We have had to change just the pump itself. We have actually changed that 2 times now because it has developed very small clots that we can see, and when we see those, we replace the pump immediately to avoid serious complications.
How big a heart can he take?
Dr. Stewart: There are other factors when we look at size. We look at the kid’s height, but you can easily accept a heart twice your size, twice your weight and it has been demonstrated where some patients can take a heart 3 times the weight depending on it. You do not want a heart smaller than he is because it has to do a little extra work. Because of his long-term dysfunction, he has higher pressures in his lungs, so he needs a very strong right ventricle to tolerate his lung pressures. We have him listed at a heart slightly bigger than he is to a little, about 2.5 times his size.
FOR MORE INFORMATION, PLEASE CONTACT:
Cleveland Clinic Children’s Hospital
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