The best way to describe it, Dr. I-Wen Wang has found, is to call it a “mini ICU.”
A tiny hospital room plucked out of the intensive care unit, complete with monitors and pumps running. A chamber – about the size of a large shoebox – that a donated heart can live in, kept warm and pumping blood, for hours and hours as it is transported to its recipient.
In the world of heart transplants, the ‘heart-in-a-box’ is a game changer and Dr. Wang, a cardiovascular surgeon, and IU Health are currently at the center of U.S. clinical trials for the device.
Officially called the OCS Heart, the portable heart perfusion system is something Dr. Wang says will open “a whole brave new world.” The device not only allows donor hearts to be brought in from much longer distances, but has even allowed hearts that have gone into cardiac arrest to be resuscitated and successfully transplanted.
The company that manufactures the “heart-in-a-box” came to Indianapolis earlier this month to train an IU Health team on the device. And, as the heart (a pig’s heart) was removed and put into the chamber – shocked and then began beating and pumping blood – it almost looked like something out of science fiction. A literal heart, standing alone, alive.
We sat down with Dr. Wang after the training to get details on this groundbreaking transplant technique. Five patients have already agreed to be part of the clinical trials at IU Health. Dr. Wang expects his first human “heart-in-a-box” transplant is just around the corner.
What is the traditional way to transport a heart for transplant?
“Historically, the organs that are being procured are always stored cold, without any blood flow,” says Dr. Wang. “Normally, when we take the heart out of the donor, we flush the heart with a preservation solution and cool the organ down to minimize damage. And then we put it on ice and we bring it back in a cooler. So, whatever you see on TV, the coolers, is exactly what it is. So ‘ER’ or ‘Grey’s Anatomy,’ it’s somewhat close to the truth.”
Explain this new ‘heart-in-a-box’ technique.
“This represents a paradigm change in that we are actually perfusing the organ with blood, with warm blood so it’s like it is inside a body as it is being transported,” Dr. Wang says. “We actually take the donor’s blood and put it in the system. It’s oxygenated and nutrients are added to it to allow the heart to continue to work. As it is traveling to the recipient, the system monitors pretty much the same as if it were in the ICU -- the blood pressure, how much blood flow is going through the heart itself, the oxygen level, the temperature and so on and so forth.”
What is the benefit of the new method?
“When a heart is transported cold, there is a finite time limit. The longer you leave it cold, without blood, without working, the more injury the organ incurs,” says Dr. Wang. “Typically, we look at trying to maintain the time from when the blood stops flowing in the donor to the time the blood flow is restored in the recipient to about four hours. The longer it goes beyond four hours, the more likely it is to have an impact on the patient’s recovery and survival. We know, for example, that beyond six hours the 1-year mortality starts to rise. So, this is a real significant thing. It allows us to limit the time that the heart isn’t working and limit the damage.”
How will this affect hearts available for transplant?
“This allows us to transport organs over much longer distances than we’ve historically been able to do because the heart is working most of the time,” Dr. Wang says. “We think this will allow us to go much further away to get hearts. For us to fly to California or Hawaii or Puerto Rico, that now becomes possible with this device, whereas historically that just would not have been possible.”
In the whole scheme of heart transplantation, how big of a deal is this?
“It will be a game changer. And the game changer is not just this portion of it. Being able to procure from a greater distance is important. Being able to use organs that probably today we would not use is important,” says Dr. Wang. “But this perfusion outside of the body may also offer us opportunities to administer specific treatment to the donor heart that can improve its outcome long term. There are things we haven’t even begun to tap into.”
Can you give an example?
“Well, the bigger question with this technique is ‘Can we customize therapy to treat this isolated donor heart to make it work even better, to last even longer when we transplant it into patients.’” Dr. Wang says. “Our ability to take the organ out and put it in isolation may down the road help us to administer all different sorts of things, whether it’s agents or drugs or stem cells. That opens a whole other possibility and that would be tremendously exciting -- an ability to customize therapy for each patient. Can we match the profile of the donor heart’s protein to the recipient’s protein then find out what the areas of mismatch might be? How we can combat it? I mean, you’re now talking about a whole brave new world.”
What is one of the most exciting possibilities with this?
“Well, one thing they have begun to tap into is the use of donation after cardiac death. Some patients donate after the heart has actually arrested and stopped. We’ve, historically, never used those hearts because the heart’s stopped,” Dr. Wang says. “But, there are more than 40-some cases worldwide using this machine, where they have recovered resuscitated hearts that have arrested and then went on to transplant them successfully. That now opens up a whole other window.”
Is this technique safe?
“It’s actually for commercial sale in Europe and in Australia. Now, in the U.S., this is a clinical study and we think it’s safe, we think it’s going to be equal if not better and so that’s what we’re about to find out,” says Dr. Wang. “That’s what I tell patients, I say, ‘I can’t promise you this is a better way to do it. I do know the study has already been done that demonstrates it’s safe and at least equal to our current way of doing it.’”
You’ve been on the “heart-in-a-box” journey for quite some time. Tell us about that.
“When I was a general surgery resident at the University of Pittsburgh, we were the first test site for this. So my attendees and I put the first human heart on this device in 2001,” Dr. Wang says. “I still remember it very vividly. It was a 79-year-old lady who passed away from a stroke and because her heart was not usable for transplant, the family agreed to donate the heart for the purpose of research. So, we took the heart and put it on the machine and it ran for about 12 hours without any problems. That was a demonstration of feasibility. I left Pittsburgh and went to University of Michigan to do cardiac training and then I went to Washington University in St. Louis. While I was there, we were set up to do the earlier version of this clinical trial, but I left before that happened. So, we’re doing it here at IU Health.”