Manuel Rodriguez-Davalos, MD, Dir, Living Liver Donor Transplant Program at Intermountain Healthcare Transplant Services talks about the benefits of live liver transplanting and how 3D printing of livers can help make a dent in the very long liver transplant list.
Interview conducted by Ivanhoe Broadcast News in May 2019.
Let’s talk a little bit about the Finleysons. Going forward was that a good case for the living donor liver program? And why is it good?
RODRIGUEZ-DAVALOS: One of the bigger problems that we have in the country right now is that we have a very long list of patients waiting for liver transplantation. And unfortunately, many of them get very sick. We think over 10% of the patients that are listed may fall off the list because they’re too sick to transplant. And although, we’re the country that does the most transplants in the world at this point and we have a great system, we still have a good number of patients that don’t make it to transplant. So, the advantage of live donor liver transplantation is that you can actually plan the case and transplant the patients on the list before they get too sick. And in Mrs. Finleyson’s case that was the case. We have a lot of patients and her disease you have autoimmune and other diseases, that we see both in young adults and in patients in her age group, oftentimes don’t get very high points to get access to livers. And so live donor liver transplants is a fantastic way of helping our patients. It also gives us a lot of time to find as much as we can about the donors. Usually these are healthy donors. And in general, I would say between 18 and 55. Although, there’s really no cap. We’ve done evaluations for people older; the evaluation process takes around two or three weeks. But we’ve had patients that have been very sick. And we’ve been able to do that live donor evaluation within one week. And again, nowadays with the new technologies we have very good evaluation of the volume and the amount of liver that the potential donor has. And we can calculate how much liver the recipient needs. The reason why live donor is important to do before the patients get to sick is because you’re not doing a full liver, you’re only doing 40 to 60 percent. And although, the liver is an amazing organ that can regenerate, you need a good amount of liver mass for the first two or three weeks as they start to recover.
Is this because of recovery? Because the livers not really big enough to handle all the functions, right?
RODRIGUEZ-DAVALOS: It’s good enough to handle the function of someone with what we call a low MELD. So the system we have right now for allocating livers in the countries called the MELD system, M E L D – the Model for End-Stage Liver Disease. It was designed at the Mayo Clinic back in the ’80s to see how sick the patients were. The higher your MELD, the sicker you are. Your MELD is too high, you need a whole liver. But if your MELD is on the lower or mid ranges even, like 40 to 50 percent of a liver should be more than enough. And as you get sicker you need more. There are variables, like the size of the donor and the size of the recipient. And Mrs. Finleyson is a small woman. And that’s why we’re able to do a left lobe transplant. Most of the adult transplants done in the country are right lobes. In our program we do both right lobes and left lobes. We also do something called left lateral segment for pediatric patients. But we feel that for donors that are not very sick and that are not very large doing a left lobe liver transplant gives enough liver for them to recover. But also it’s a safer surgery for the donor and the recovery is much faster. The average length of stay of a left lobe donor is four to five days.
And for this procedure you use the 3-D printing?
RODRIGUEZ-DAVALOS: Yes.
Can you tell me how that worked in?
RODRIGUEZ-DAVALOS: We’ve been working for almost five years now on different technologies, even before I moved to Salt Lake City. 3-D imaging is very important to know, not only the volume of the liver that the donors donating but also the volume of the liver that they’re keeping. The most important thing about live donor liver transplantation is the safety of the donor because you have someone that’s completely healthy making this amazing gift and a sacrifice for their loved one. So we have to measure the volumes of the liver and then understand the anatomy. There are different connections that we do for other types of transplant. So, we started with 3-D imaging which is fantastic because it can help us manipulate doing the transplant OR the different angles of the vessel. And then we start to work with the innovation team. Many of them engineers with biomedical backgrounds that can actually print a model of the liver and they can make it the same size of the liver of the donor. And inside they can give us the anatomy of all the vessels and bile ducts that we have to connect. It gives you a completely different perspective on the volumes and how to plan the surgery. This is something that is being used in the space and a lot of that aromatic modeling. I think in many things we need these types of tools to make it safer for our patients.
This is the first time that’s been used for this, is that right?
RODRIGUEZ-DAVALOS: It was the first time used for an adult to adult case in the state of Utah. We had used it on some of our pediatric cases. Live donor liver transplantation started back in the late ’80s with pediatrics because the patients that were waiting the longest because of the size were children, so parents would donate. Now it has grown so much all over the world that it’s a known thing. Now we have it as a routine to do the 3-D modeling of our donors. And we recently applied for a grant for research trying to actually print the donor and the recipient and then keep them in like a library of livers. The cranial facial surgeons do this a lot. They 3-D print the surgeries they’re going to do. So if we can 3-D print now and understand the anatomy and the variation in the liver it’s not only going to help our patients now but patients in the future. And it’s going to help us train a lot of future surgeons on how to do these procedures.
How much easier did having 3-D printed livers make that transplant for you?
RODRIGUEZ-DAVALOS: I think it makes a big difference. We always say transplantation; especially liver transplantations are teamwork. So, we have multiple surgeons. There are two surgeons on the donor surgery and two surgeons on the recipient’s surgery. We need a week before to kind of go over the steps of surgery and plan everything. The fact that we’re able to kind of go over step-by-step it’s just so much easier than just seeing a cat scan on a screen. The other thing I think is it helps everyone. It helps the patient understand. It helps the donor understand and know the risk in how things are going. Part of the current research we’re doing is also a year after donation, do another 3-D modelling to see how the liver has grown on each side. Because there have been few studies to understand how the liver grows and what would happen with these donor recipients 10 – 20 years from now. So, I think there’s so much to learn. But it does make it so much easier to do this surgery when you can actually know everything before even getting in there.
I know the families said that being able to look at it and touch it and feel it made it easier for them.
RODRIGUEZ-DAVALOS: Her case was also challenging in particular because she had had a previous liver resection done here back in 1983. So, we also did a 3-D model of her own liver. They had resected the whole right lobe of her liver. So, it was very good to actually see her anatomy with a 3-D printing model. And then the anatomy of her son and kind of plan how we were going to do the different angles of the veins and vessels. Taking in to account how the liver is going to grow over time in her. Because one of the amazing things some people don’t know about the liver is that within three weeks to three months from donation 90% of the volume that was donated will regenerate. So when we plan these surgeries, we need to think what it’s going to be that growth like to prevent any complications later.
So it was his left lobe that replaced her right?
RODRIGUEZ-DAVALOS: No. His left lobe for her left lobe.
Oh, OK.
RODRIGUEZ-DAVALOS: Her liver had grown because she had a resection in the ’80s, her liver had grown to normal size. So it was just the anatomy that was the anatomy of a left lobe.
What haven’t I asked you that you think is important to get across?
RODRIGUEZ-DAVALOS: One of the things is that as live living donor continues to increase all over the world. I think in the U.S.; we went through a plateau. We were one of the countries that have – had the biggest growth in the ’90s when I started to get training in these. And then after 2001, it was just low. And in the last two years, there’s been a big increase all over the country. And I think it’s because we know that there’s a lot of people waiting, and we know that the results are actually as good as this is donor. There are some studies and disinformation depending on the diagnosis and other things. But there are some studies that have shared that actually with a 10-year follow up there’s some live donor transplants that have better results than a deceased donor. I believe that every hospital in the country should be able to offer living donation. And I think that we have a lot of patients that are waiting. And someone like Mrs. Finleyson shows a very important message and her case is that I don’t think because of her age and the stature of this is she would not have been able to get a deceased donor otherwise because at the rate of her disease would have been too much for her to get high enough on the list. Another important thing about living donation is that in 2018 it was the first time the country in the last 15 years that we’ve done more live donor liver transplants in the country.
Do many other places use the 3-D printing to assist in surgery?
RODRIGUEZ-DAVALOS: I know the first publications came out from Cleveland Clinic in Ohio. And they’ve used to it routinely. Mayo Clinic has now almost a whole library. They use it for a lot of their surgeries. When I came on I had been working before here at Yale New Haven transplant center and that’s where we started to use some of the 3D printing modeling. The next step is really doing what we call bio-3-D printing which is a venture with this type of technology we’ll be able to print vessels or bio ducts. And again it sounds like science fiction. But I think that’s where we’re going. We’ve had some research when I was at Yale where we actually printed vessels that were part of surgical and were actually implanted in animal models. Here, we started to do some research on bio 3D printing too. I think that’s where we’re heading in the future.
RODRIGUEZ-DAVALOS: Hopefully one day we can print your own liver and we wouldn’t need transplants.
END OF INTERVIEW
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