November 15, 2000
MEDIA CONTACT : Karen Infeld
Blood Components Indicate Risk of Rejecting A Transplanted Heart
Two tiny substances in the blood might alert physicians to which heart
transplant patients are likely to experience some form of organ rejection,
a Johns Hopkins study indicates.
For the study, researchers collected 132 blood specimens and heart tissue
samples from 35 patients between February 1997 and May 1998. The higher
the level of the substances prothrombin fragment (PF) 1.2 and p-selectin û
substances circulating in the blood that are involved in clotting û the
higher the rate of rejection, researchers found. Low levels of both
substances predicted that the specimen would be free of rejection 88
percent of the time. In addition, patients with a p-selectin level of at
least 65 nanograms per milliliter were 21.4 times more likely to have
rejection diagnosed in the biopsy specimens from their new hearts compared
to those with lower amounts of the substance.
Chronic organ rejection is the Number 1 reason patients need a second
transplant. Biopsies, which are done multiple times in the first few weeks
and months following the transplant, are currently the only way to
accurately detect organ rejection. Even after two years, many patients
still must undergo biopsies two or three times a year.
In this study, the PF 1.2 and p-selectin levels accurately predicted what
the biopsy would look like, says Jodi B. Segal, M.D., M.P.H., lead author
of the study and an assistant professor of medicine at Hopkins.
"Perhaps these blood measures could reduce the number of biopsies needed by
transplant patients, and allow us to monitor them noninvasively," she
says. "Mechanistically, they also tell us something about how
platelets û blood components involved with clotting û are functioning, and
suggest that anti-platelet agents should be further studied for prevention
of organ rejection."
American Heart Association 73rd Scientific Sessions
Information on Heart Disease Treatments at Johns Hopkins