When it comes to the success of liver transplantation, there are three key risk factors that play a primary role. That's the conclusion of a new study from Vanderbilt University Medical Center in Nashville, Tennessee.1
A Clearer Prognosis
"From these findings, we can develop preliminary models of pretransplant characteristics to help predict post-transplant survival," wrote Derek Moore, MD, in the department of Surgery at Vanderbilt University Transplant Center, and his colleagues.
The three factors are donor age, the length of time an organ is cooled between procurement and transplantation, and how urgently the recipient needs the transplant.
According to the researchers, nearly 2,000 people with end-stage liver disease die every year waiting for a suitable donor liver. In the year 2000, there were almost 17,000 candidates awaiting a liver transplant, but only 5,000 underwent the procedure.2 Thus, to help expand the supply of necessary donor livers, organs from donors that are not judged to be optimum for a variety of reasons are now considered for a possible transplant, according to Moore's team. Keeping that in mind, the focus of this study was determining the factors that have the most impact on patient and organ survival, which could not only increase the donor pool, but also shorten the wait for liver transplantation.
What Factors Are Linked to Transplant Success?
To ascertain that information, Moore's group collected data on all adult patients who underwent a liver transplant for end-stage liver disease at Vanderbilt University Medical Center between 1991 and 2003. The researchers included three categories of risk factors in their analysis: donor characteristics; including age and weight; technical characteristics, including cold ischemia time (the length of time an organ is cooled between its removal from the donor to the moment the transplant is performed); and cases in which opposing genders were involved in a transplant (male donor and female recipient, for example).
Other factors considered included the urgency facing a particular patient on the liver transplant waiting list and a patient's cause of liver disease. In all, nearly 500 liver transplant cases were studied.
The Three Keys to Improved Survival
After analyzing all the data, Moore and his colleagues determined that a donor age 60 years or older, a cold ischemia time of 12 hours or more, and a patient's urgent status on the transplant waiting list were independent risk factors for both shortened organ and patient survival in these procedures. "Five-year graft survival [the odds that a transplanted liver will not become diseased 5 years after transplant] was 72% for recipients of donors younger than 60 years, and 35% for recipients of donors 60 years or older," Moore's group wrote. "A cold ischemia time of 12 hours or more was associated with shorter 5-year graft survival (71% versus 58%)."
The 5-year organ survival rate in cases in which a patient on the waiting list had an urgent need for a transplant was 60% versus 71% for patients with less of an urgency, the researchers noted.
Using an example based on their findings, Moore said that a liver transplanted from a donor under age 60 into a recipient with a less-than-urgent status on the transplant waiting list would likely face a 75% chance of surviving 5-years after the procedure. By contrast, a liver transplanted from a donor older than age 60 into a recipient with an urgent status on the waiting list and a cold ischemia time of more than 12 hours would face only a 20% chance of survival 5 years after transplantation.
What's Next?
In future research, Moore and his colleagues want to confirm their findings by using a database of liver transplant donors and recipients managed by the United Network for Organ Sharing, a non-profit scientific organization that manages the nation's only Organ Procurement and Transplantation Network (OPTN), established by Congress in the mid-1980s. Their long-term objective is to create a set of variables that will accurately predict posttransplant and patient survival for a given case.
"Such a model could be used to make recipient-specific organ allocation decisions at the time of graft procurement," Moore said.
1. Moore DE, Feurer ID, Speroff T et al. Impact of donor, technical, and recipient risk factors on survival and quality of life after liver transplantation. Arch Surg 2005 Mar;140(3):273-7.]
2. The Organ Procurement and Transplantation Network. United Network for Organ Sharing (UNOS).
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
