Formula to predict heart transplant success
Baltimore, September 1, 2011
A new formula can predict which heart transplant patients are at greatest risk of death in the year following their surgeries, said researchers at US-based John Hopkins Medicine.
This information that could help medical teams figure out who would benefit most from the small number of available organs, they added.
“Donor hearts are a limited resource,” says John V Conte, MD, a professor of surgery at the Johns Hopkins University School of Medicine and the senior author of the study.
“Now, we have a simple-to-use tool that is highly predictive of survival after a heart transplant, and can help guide organ allocation decisions.”
Conte and his colleagues, writing in the September issue of Annals of Thoracic Surgery, pulled together a series of risk factors already associated with poor outcomes, such as age, race, gender, the cause of a patient’s heart failure and whether he or she was on dialysis, and then assigned a number of points to each factor.
The sum of those points created a score. The higher the score, the higher the risk of death one year after transplant.
Some factors were weighted more heavily than others, such as female gender (three points); African-American race (three points), and the need for dialysis in the time between being put on the transplant waiting list and getting a transplant (five points).
Patients with the lowest scores — between zero and two — had a 92.5 per cent chance of being alive 12 months after surgery.
Patients with so-called IMPACT scores — the acronym the researchers came up with for the Index for Mortality Prediction After Cardiac Transplantation — above 20 points had a less than 50 per cent chance of survival one year after surgery. Every point on the scale increased the chance of death within one year by 14 per cent.
“As clinicians, we make an educated risk of what the risk is going to be,” said Conte. “This tool provides a quantitative way to assess the risk.”
To develop and test the validity of IMPACT, Conte and his team analyzed data provided by the United Network of Organ Sharing comprising information from all heart transplants — 21,378 of them — conducted in the US between 1987 and 2010.
More research is needed to learn what role is played by factors other than the recipient’s risks, Conte said.
Results of their study suggest, for example, that an organ coming from a donor over the age of 50 or one that has been outside the body for more than four hours also increases the risk of death in the recipient, he added. – TradeArabia News Service