New York.– A simple blood test may detect whether a chronic heart transplant patient is rejecting their heart, and may reduce the need for invasive heart-muscle biopsies, according to the results of a multi-center study called CARGO (Cardiac Allograft Rejection Gene Expression Observational Study), led by NewYork-Presbyterian Hospital and Columbia University Medical Center and to be published in the December 19 The American Journal of Transplantation. 

The findings describe a new methodology that may impact the way heart transplant patients are treated.  

The four-year, eight-site CARGO study included data from centers accounting for approximately 22 percent of the yearly U.S. heart transplant population.  

The gene-expression test, called AlloMap™ molecular expression testing, developed in partnership with XDx, a molecular diagnostics company in South San Francisco, CA, and using data from more than 600 patients, presents a snapshot of the immune status of the transplanted heart recipient.  

This snapshot represents a profile of 20 genes representing molecular pathways in white blood cells that were found to be associated with heart transplant (allograft) rejection, and control genes. Following its development, the study conducted a blinded clinical validation of the AlloMap test.  

The AlloMap test in this study appeared to distinguish patients who were rejecting their heart from those who were not. Patients with a low AlloMap score had a less than one percent chance of rejection.  

"The genomics revolution ushered in by the completion of the Human Genome Project has made possible what was only dreamed about before-namely the ability to detect rejection of the transplanted heart without taking a tissue sample," says Dr. Mario Deng, the study's co-principal investigator and co-lead author of the publication.  

He is director of cardiac transplantation research at Columbia University Medical Center, assistant professor of medicine at Columbia University College of Physicians and Surgeons, and attending cardiologist at NewYork-Presbyterian/Columbia.  

AlloMap molecular expression testing is a service provided by XDx through its clinical laboratory, which is CLIA- (Clinical Laboratory Improvement Amendments) certified to perform AlloMap testing for heart transplant patients nationwide. NewYork-Presbyterian/Columbia will begin offering patients AlloMap testing on January 1, 2006.  

After the first year of transplant, heart transplant patients have an average risk of three to five percent for moderate/severe rejection. Consequently, for the rest of their lives, patients must be monitored for rejection to guide their immunosuppressant drug therapy. Rejection of a transplanted heart can lead to heart damage and eventual failure and loss of life.