Blood test better for coronary arteries

ORLANDO, Fla., Nov. 15 (UPI) -- A blood test is more effective to rule out obstructive coronary artery disease than a test that uses a radioactive agent, U.S. researchers say.

Dr. Gregory S. Thomas, clinical professor of medicine and director of nuclear cardiology education at the School of Medicine at the University of California, Irvine, said the blood test used gene expression, which provides valuable tissue and cell-specific information about the molecular mechanisms involved in disease processes.

Unlike genetic tests, which measure genetic variations, mutations, traits and predispositions -- factors that are constant over a person's lifetime -- gene expression testing assesses a dynamic process, integrating both genetic predisposition and additional behavioral and environmental influences on current disease state.

The study involved 537 stable patients with symptoms suggestive of coronary artery disease who had been referred to myocardial perfusion imaging at 19 U.S. sites.

Following myocardial perfusion imaging, patients were referred either to invasive angiography or to CT angiography, gold-standard measurements for diagnosis of coronary artery disease. A total of 431 patients were eligible for analysis, having completed gene expression testing, myocardial perfusion imaging and either invasive angiography or CTA.

The study found the blood-based gene expression test was superior to myocardial perfusion imaging in diagnostic accuracy and demonstrated excellent performance for ruling out obstructive coronary artery disease.

The findings were presented at the American Heart Association Scientific Sessions conference in Orlando, Fla.