Lung transplant
February 9, 2010
A group of doctors at the Puerta de Hierro hospital in Madrid have performed two groundbreaking lung transplants with a technique that involves the preservation, testing and treatment of the lungs outside the body. The practice, known as ex-vivo perfusion, uses a machine to preserve, control and treat the organs outside the body.
Since 2001, 36 transplantations have been performed using this technique in Sweden, Canada and Great Britain. But this is the first time that it has been used with lungs from donors who have died from cardiac arrest in the street or in their home. All the other donors have been patients who have been declared brain dead in hospital.
All vital organs are fragile and have a short shelf life once the body has stopped supplying them with oxygen-laden blood. But according to Dr. Francisco Javier Moradiellos, one of the thoracic surgeons on the transplant team, lungs are especially vulnerable and lose their viability after just six hours. Because of the amount of time the operations take, that has meant that up until now, both the recipient and the donor had to basically be in the same hospital.
"For the first time in the world we have been able to evaluate lungs from non-heart beating donors and control non-heart beating donors with the ex vivo perfusion technique," he told Deutsche Welle. "The novelty is that it is not just retrieving and transplanting, but we are adding a middle stage which is evaluating these lungs."
Recreating the human body
The ex-vivo technique works by reproducing the conditions of the human body. The lungs are placed in a machine and set up with blood circulation, ventilation, and a constant temperature of 37 degrees Celsius (98.6 degrees Fahrenheit). An external pump drives a special solution, which does the job of blood, through the vessels. And there is a set of sensors that give information about the state of the lungs in real-time.
The machines are particularly good at resuscitating lungs damaged by fluid buildup, known as pulmonary edema, which is often the result of brain death. Moradiellos said that a lot of lungs have been rendered unusable because the donors have died outside of a hospital and were not hooked up to machines that keep the body and the organs within them viable.
In addition, according to Professor Dirk van Raemdonck, Surgical Director of the Lung Transplant Program at the University Hospital in Leuven, Belgium, the successful transplant of some organs is more critical that others. He has worked extensively with the ex-vivo technique and has followed this new development in Madrid with interest.
Van Raemdonck told Deutsche Welle that the "technique is very useful, because you can monitor the lung for several hours outside the body."
"Because if you compare it with a kidney transplant, for instance, if the kidney is not working, you can put the patient back on dialysis and you can wait until the kidney will start functioning again, let us say, a week after the transplant," he said. "You can't do that with lungs and heart, because they need to begin to function immediately.”
Number of lung transplants could increase
Last year Spanish doctors performed 219 lung transplants. Since 1990, there has been a total of 2,237 of these operations in the country's hospitals. This places Spain in the top league in the field of lung transplants. As in the general field of organ donations and transplants, where Spain with a total of 34.3 donors per million inhabitants, almost twice the EU-average, is the world leader.
That is mostly due to the fact that in Spain, unlike in Germany, the UK or the US, organ donation is not something you sign up for. The Spanish assume that unless a person specifically states that they do not want their organs to be donated, they are a potential candidate. Still, in 2009 there where 160 people on the waiting lists for a lung transplant in Spain.
The doctors at the Puerta de Hierro hospital perform between 35 and 45 lung transplants a year and Moradiellos expects this number to rise dramatically with the application of the new technique. According to his calculations, they might be able to retrieve 25 more valid lungs each year.
"Once all groups are working with this technique we might be able to increase, perhaps by 20 or 25 percent, the number of lung transplants performed yearly," he explained.
And the ex-vivo machines will have many potential uses. The most amazing, according to Moradiellos, will probably be the use of gene therapy and stem cell therapy, something the Canadians are already working on.
Treating the lungs before transplanting means they can also personalize those lungs to the particular recipient to which they are destined. And this is very important.
"That would reduce the risk of rejection and overall we hope it will improve the results of lung transplantations," said Moradiellos.
Author: Mikkel Larsen
Editor: Mark Mattox