A new study led by researchers at the Scripps Translational Science Institute (STSI) validates that a promising gene expression test may be useful in helping doctors sort out which patients are the best candidates for angiograms, and who can potentially be spared the invasive diagnostic procedures.
The findings are significant, as more than 2 million U.S. patients undergo angiograms each year. The study will be published Oct. 5, 2010 in the Annals of Internal Medicine, the journal of the American College of Physicians.
Physicians are often challenged in diagnosing obstructive coronary artery disease, which results from fatty cholesterol buildups inside the arteries that nourish the heart muscle. After assessing a patient’s medical status and symptoms, doctors usually order stress tests. If these prove inconclusive, they may order angiograms, in which a thin tube is threaded up to the heart and dye is injected to check for blocked arteries.
The Scripps findings follow a study published earlier this year in the New England Journal of Medicine, which revealed that among 400,000 patients without known heart disease who underwent elective angiograms, 62 percent didn’t have evidence of significant obstructions. That study, sponsored by the American College of Cardiology, suggested physicians need to do better in determining which patients should have angiograms.
Led by principal investigator Dr. Eric Topol, director of STSI, the independent validation study involved 526 non-diabetic patients in 39 U.S. hospitals, including Scripps Green Hospital in La Jolla, Calif. The two-year study analyzed results from a gene expression test that looked at cells in the patients’ blood, and then compared them to outcomes from their angiograms.
“The critical question that we addressed – can the gene expression from white blood cells provide information about blockages of the coronary arteries? – was answered and validated in a select cohort who also underwent angiography,” Dr. Topol said. “The findings may help our future ability to direct coronary angiography to the patients with real clinical need.”
The study was co-authored by scientists from leading research organizations across the U.S., including STSI; Duke University; Vanderbilt Heart and Vascular Institute; Minneapolis Heart Institute Foundation; Piedmont Heart Institute; Washington Hospital Center; Oklahoma Cardiovascular Research Foundation; Cleveland Clinic; and Cardiovascular Research Foundation of New York.
The study was funded and co-authored by CardioDX, a cardiovascular genomic diagnostic company. An independent statistical validation of the study was completed by STSI without any funding from the sponsor.