For many Americans living with a heart transplant, invasive heart-muscle biopsies that check for organ rejection are a fact of life.
However, a simple blood test that analyzes a patient's genes, introduced in 2005, has been evaluated by leading transplant centers and their experience verifies it can detect the absence of heart transplant rejection, according to data reported in a new study authored by a consensus team of international heart transplant experts and published in the December 2006 edition of the Journal of Heart and Lung Transplantation (JHLT).
In 2006, results from the CARGO (Cardiac Allograft Rejection Gene Expression Observational) study were published and reported on the utility of a gene expression profiling (GEP) test, called AlloMap® molecular expression testing, which had been commercially available for nearly a year.
Developed by XDx, a molecular diagnostics company in Brisbane, Calif., the test is currently offered at 40 transplant centers in the United States.
"AlloMap testing is not only less invasive and less risky than biopsy, it also monitors the absence of organ rejection and raises the suspicion of damage before any damage to the heart happens.
Biopsy records damage that has already occurred," says Dr. Mario Deng, the article's corresponding author. Dr. Deng is director of cardiac transplantation research and associate professor of clinical medicine at Columbia University College of Physicians and Surgeons, and a practicing cardiologist at New York-Presbyterian/Columbia University Medical Center.
Approximately 30 percent of all heart transplant patients reject their new heart at least once in the first year after transplantation. When testing reveals organ rejection, a patient's immunosuppressive regimen is adjusted.
"The Cleveland Clinic was the first transplant center in the United States to use the AlloMap test to follow patients after cardiac transplant," said Dr. Randall C. Starling, the editorial's first author and vice chairman of cardiovascular medicine and section head of heart failure and cardiac transplant medicine at Cleveland Clinic.
"There is clearly a need for new methods to determine the best way to manage heart transplant patients. Gene expression profiling appears to be the future, and holds the potential to improve accuracy of diagnosis, reduce the need for invasive procedures and reduce cost. Additional research is necessary, but we are encouraged that gene expression profiling will improve the care of our patients."
Based on the new data published as an invited editorial, in more than 99 percent of cases, the AlloMap test successfully predicted the absence of moderate or severe acute cellular organ-transplant rejection. These results confirm the findings of the CARGO study.
The AlloMap test was developed to rule out rejection, meaning that a low test score very reliably identifies transplant patients who are not rejecting their transplanted heart.
"Many of the premier transplant centers in the United States have incorporated AlloMap testing into their treatment protocol and physicians are relying on the test to accurately manage the care of heart transplant recipients," said Pierre Cassigneul, president and chief executive officer of XDx.
"The invited editorial in JHLT further validates the usefulness and accuracy of AlloMap testing. We are pleased to see continued confirmation of the test's abilities from real-world use."