Maryland Shock Trauma Center patients who had previously undergone kidney, liver, lung and other organ transplants recovered as well as the general population, according to a University of Maryland study that experts say demonstrates the resiliency of transplanted organs.
But they were more likely than their peers who had not suffered traumatic injuries to later reject transplanted organs, the study found. That raises new questions about the immune response that trauma can trigger and how it affects transplant patients.
The study gave a rare look at a subset of patients that is difficult to study for most medical centers.
"It's very encouraging to see how robust the reserve of these transplanted organs really is," said Dr. Daniel Salomon, president of the American Society of Transplantation. "They can handle the most extreme challenge that a human body will face."
That runs counter to the assumptions of many doctors. About 28,000 organ transplants are performed across the country each year, and about 124,000 people are living with transplanted organs in the U.S., according to the Health Resources and Services Administration. While the short-term survival rate for transplant recipients has improved drastically in recent decades, to as high as 99 percent within a year post-transplant, the survival rate beyond a decade is about 50 percent.
Maintaining function in a transplanted organ requires a regimen of drugs that suppress the patient's immune system so that it doesn't attack and reject the organ. The drugs must be taken for the rest of a person's life.
To explore how transplanted organs fared during traumatic injuries, three surgeons looked retrospectively at patients who visited Shock Trauma from 2007 through 2011. Given that the University of Maryland Medical Center has relatively high patient volume both in transplants and trauma, they believed they would have enough data.
Of more than 13,000 patients who visited the trauma center in that span, 50 had received organ transplants. Most received donated kidneys, some along with the pancreas, while others had received a new liver or lung.
Of those 50, four received some injuries to their transplanted organ, three of them maintaining organ function. Overall, the patients spent about an equal amount of time in intensive care and had similar rates of bone breaks and infections as patients who had not received organ transplants.
"You would have thought that wouldn't be true, but it turns out it is true," said Dr. Thomas Scalea, physician-in-chief at Shock Trauma and senior author on the research paper, published last month in the Journal of Trauma and Acute Care Surgery. "I was a little surprised."
The paper's authors say that while it doesn't provide absolute proof, it suggests there may be less to worry about for transplant patients.
"It provides you a little bit of reassurance that when these patients show up at a trauma center, we know they're not going to do any worse, at least in the first several months," said Dr. Joseph Scalea, lead author on the paper and a surgeon at University of Maryland Medical System (and Thomas Scalea's nephew).
While they recovered from their trauma injuries just as well as other patients, some faced difficulties that other organ transplant patients don't. About 17 percent of the organ-transplant patients suffered from organ rejection within six months of their traumatic injuries.
The surgeons say that raises more questions — and the need for research — about the body's response to trauma. Inflammatory immune system responses to such injuries include pain, swelling and loss of organ function, and they are marked by a surge in white blood cell counts. The transplant patients showed significantly lower white blood cell counts after traumatic injuries than non-transplant patients, possibly because of the immune-system-suppressing drugs they take.
Those drugs, the doctors thought, might have contributed to transplant patients' faring poorer after trauma. The patients recovered well, but in some cases it appeared the inflammatory response to injury contributed to organ rejection.
To explore further, the doctors would like to perform an active study (as opposed to a retrospective one using hospital data) that looks more closely at inflammation indicators and studies patients with the most severe injuries, Thomas Scalea said.
"This study asks us to ask more questions," he said. "You rarely definitely answer something."
But in the meantime, it offers encouragement to organ transplant patients who are eager to move on with their lives, said Dr. Stephen Bartlett, surgeon-in-chief for University of Maryland Medical System and another of the paper's authors.
"We tell people to live a normal life, and now we have a journal article that tells us that's actually the right answer," Bartlett said.