When I was a teen in the 1970s, listening to a lot of music and watching a lot of television, there was a company called Memorex. It made audio tapes to record music on. (Yes, I lived in the age of the dinosaur, long before iPods and iPhones). There was a very popular commercial that instantly became a classic. It showed Ella Fitzgerald singing a note that shattered a glass while being recorded to a Memorex audio cassette tape. The tape was played back and the recording also broke a glass. A narrator asked the question: "Is it live, or is it Memorex?" This would become the company slogan which was used in a series of advertisements released through the 1970s and 1980s.
So when thinking about heart transplants, one wonders if there is an option to transplant a mechanical heart versus a human heart. And if there is, which option would be better – live or the heart version of Memorex? I recall that years ago there were some experiments with artificial hearts. But I lost track (and at that time probably interest) in whether there was any progress made with artificial hearts. But now that the heart (and the threat of worsening heart failure) basically rules every minute of my day, I have become extremely interested in this topic.
So you are probably asking why anyone would prefer an artificial heart to a human heart. I suspect that for most of us, a human heart, which is what we have been living with for years, is the preferable option. But is it always the available option?
First, the good news: Doctors have been performing successful human heart transplants for over 50 years. According to a March 26, 2012 article on the website for the Daily Beast, there are approximately 5,000 heart transplants each year, to include 2,000 in the United States alone. The article also tells us that at any given time, there are 3,000 people waiting for a heart.
So it looks like the demand for a human heart to transplant very much exceeds the supply. The average wait time for a heart is between six months and a year, and this means that some patients will die while they are on the wait list. According to the United Network for Organ Sharing (UNOS), the organization that manages the transplantation program, here are the factors that are considered in selecting a donee: medical urgency, time spent on the waiting list, organ size, blood type and genetic makeup. The organ is offered first to the candidate that is the best match.
According to the Cleveland Clinic website, there were initially two obstacles to heart transplants: The first obstacle was the rejection of the donor organ by the patient. This obstacle was overcome in 1983 after the drug cyclosporine was introduced to suppress rejection of a donor heart or heart-lung by the patient's body.
According to the Cleveland Clinic, cyclosporine and other medications to control rejection have significantly improved the survival of transplant patients. About 80 percent of heart transplant patients survive 1 year or more. About 60 percent of heart-lung transplants live at least 1 year after surgery. Research is under way to develop even better ways to control transplant rejection and improve survival.
As already mentioned, the second obstacle to increasing the number of successful heart transplants still exists: organ availability. Hospitals and organizations nationwide are trying to increase public awareness of this problem and improve organ donation and distribution. I think this is a good goal. But there are mechanical devices that doctors use to help someone bridge the time until a heart can be found. So that is what leads me to ask if it is possible that a mechanical device, more commonly referred to as an artificial heart, can be developed to replace the human heart?
About the time I had this question, a friend sent me an article from a recent Wall Street Journal. The article was a review of a book chronicling the bumps in the road in the efforts to create a safe and efficient artificial heart. The book “Ticker” by Mimi Swartz covers the ground-breaking work to related to devices to assist the heart, as well efforts to create a viable artificial heart. She also covers the effort in the 1980s to implant an artificial heart into a human. I remember reading about it at the time. The patient was Barney Clark, the procedure was in performed in Utah and the heart was the Jarvik 7. According to Ms. Swartz, Clark lived for 112 days with the artificial heart, but there were so many complications that the case seemed to cast doubt on the whole artificial heart enterprise.
So if the medical experts can create a viable heart, what is the problem? According to a March 2018 article in the MIT’s Technology Review website, “building one that imitates a real heart over a long period of time without breaking or causing infections or blood clots is incredibly difficult. One problem is that the more parts there are, the more things could go wrong.”
The article also tells us that only one artificial heart, made by SynCardia, is currently available in the US. It is meant to be a temporary fix while patients wait for a heart transplant, requiring patients to carry around an external air compressor in a backpack that pumps the implanted artificial heart from the outside. So it’s obviously not a perfect fix, but it certainly beats having your heart give out with no substitute.
An article on the website of the Heart Foundation says: “Research is being done in several areas to improve the quality and the use of artificial hearts. Researchers are looking into reducing the size of artificial hearts so that they can be totally implanted inside the chest. Work is also being done to develop artificial heart batteries that are small, long-lasting and implantable, and which can be recharged across the patient's skin. Biologically superior materials are being developed to reduce the tendency for blood to clot and the need for blood-thinning medicines (anticoagulants).”
I was confused when I saw the articles about artificial hearts and wondered if what they were really talking about was a Left Ventricular Assistive Device (LVAD). The answer appears to be no. The literature refers to the differences between LVAD and the total artificial heart (TAH). According to the website Syncardia:
It appears that the Total Artificial Heart has come a long way. I found an article dated May 21, 2010 on the CBS website. Charles Okeke lived for 10 years with a heart transplant before his body rejected the heart and his body was not ready to accept a new heart. The News Scientist website tells us that from September 2008 until May 2010 Okeke apparently had an artificial heart, but had to live in the hospital attached to a 400 pound machine. Okeke was the first to receive the much smaller version of the SynCardia Freedom Driver that was small enough to fit into a backpack that he must wear continuously.
In addition to the artificial heart, there is another interesting technological advance that has appeared on the scene: 3D printing. An article in the Washington Post on August 12, 2018 discussed 3D printing. What exactly is 3D printing, and does it have a role in creating organs that can be used for transplantation? The Post article referred to 3D printing as additive manufacturing.
So what is additive manufacturing? According to the Department of Energy website, it is an emerging manufacturing practice that allows researchers to create physical, three-dimensional objects directly from a computer design file. It’s similar to how common desktop printers form images—but instead of ink, 3D printers use a wide variety of materials ranging from polymer composites, metals and ceramics to food, foams, gels, and even living tissue. The Post article tells us that one of the most exciting areas of additive manufacturing is bioprinting which includes making customized 3-D-printed prosthetics and orthodontics, and most hearing aids. So are bioprinted organs far behind, or is this still just a pie in the sky idea?
Well at least not as of September 2015 when the Smithsonian Magazine featured an article entitled: “Soon, Your Doctor Could Print a Human Organ on Demand.” But the solution for heart failure patients must involve more than just producing a human organ. After reading the Smithsonian article and researching this for a while on line, the problem is that you need to create the tissues and internal environment for the organ to work inside the patient once it is transplanted. But I have to think that the advances in technology will soon surmount and overcome the lingering issues. I think I would consider a 3D printed heart as long as I didn't run out of toner cartridges (only kidding!).
So are the only options for heart transplant candidates either to wait for a human heart to be available or to wait for technology to create a viable free-standing artificial heart? Well there is a third option according to an article on the Time Magazine website dated February 15, 2018. The article discusses work of a group of scientists led by George Church, a professor of genetics at Harvard Medical School. According to the article: Using a new DNA editing tool called CRISPR, Church and his team generated more than a dozen pigs that were bred without certain viruses that had made many of their organs unusable for human transplant.
The article said: “Church anticipates that pig-to-human organ transplant clinical trials could happen in as little as two years, which would help address the organ shortage that keeps more than 110,000 people on the transplant list each year. Currently, heart valves from pigs are used to replace diseased or damaged ones from people, but doctors are studying ways that other tissues, like those from the kidney, liver, lungs or pancreas, may be safely transplanted.”
According to the Food and Drug Administration (FDA) website, this practice is known as xenotransplantation, which “is any procedure that involves the transplantation, implantation or infusion into a human recipient of either (a) live cells, tissues, or organs from a nonhuman animal source, or (b) human body fluids, cells, tissues or organs that have had ex vivo contact with live nonhuman animal cells, tissues or organs.”
The FDA also says that “although the potential benefits are considerable, the use of xenotransplantation raises concerns regarding the potential infection of recipients with both recognized and unrecognized infectious agents and the possible subsequent transmission to their close contacts and into the general human population. Of public health concern is the potential for cross-species infection by retroviruses, which may be latent and lead to disease years after infection. Moreover, new infectious agents may not be readily identifiable with current techniques.” Apparently this is why the use of the CRISPR tool by Church and his team is so significant.
It is an interesting concept, albeit a little creepy. I am aware of people who have the pig heart valves. But that is just a portion of the heart – not the entire heart. (For some reason when I think of pigs, my mind goes to Ms. Piggy the Muppet – with her pearls, her blond hair with the flip, and the ever constant “Moi” coming from her lips. Will I turn into a Ms. Piggy clone if I have a pig heart?) Regardless of being a bit creepy, it shows how far we have come that this is something that is on the drawing board and may become a reality within a matter of a few years.
I guess the bottom line for me is that scientists continue to search for organ transplant options that are available, and maybe even more plentiful, than human organ transplants. Each of the options has its own set of benefits along with its own set of risks, and some options may sends some chills up our spines if we overthink them. At this point, none of the options discussed ready for prime time - yet. But each is a beacon of hope for those of us who have weakening hearts but may be able to hang in there until new options are perfected.
So when it comes right down to a replacement heart, it isn’t important to me whether it is live or whether it is Memorex. It will just need to work better than the heart that is currently inside me.
Melanie discovered that she had heart failure in 2013. Since that time, she has been learning how to live with the condition, and how to achieve balance and personal growth.