Blood-based genomic test better than imaging test for ruling out obstructive coronary artery disease

November 15, 2011
The gene expression test measures changes in blood cell RNA levels that are sensitive to the presence of coronary plaque. Credit: CardioDx

A blood-based gene expression test was found to be more effective for ruling out obstructive coronary artery disease in stable symptomatic patients than myocardial perfusion imaging (MPI), a common test that uses a radioactive agent to evaluate the blood flow and function of the heart.

Study results were presented today at the Scientific Sessions 2011 conference in Orlando, Fla.

"In this real-world patient population, the test demonstrates very high sensitivity and negative predictive value, enabling clinicians to rule out patients who do not have obstructive with high accuracy," said Dr. Gregory S. Thomas, clinical professor of medicine and director of nuclear cardiology education at the UC Irvine School of Medicine, who presented the findings. "The use of this test, followed by MPI for higher scores, may optimize diagnostic performance and utilization of health care resources."

Gene expression testing provides valuable tissue and cell-specific information about the involved in disease processes, enabling evaluation of an individual patient's disease state, activity, and/or progression at a given point in time. 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 COMPASS study enrolled 537 stable patients with symptoms suggestive of disease who had been referred to MPI at 19 U.S. sites. A blood sample was obtained in all patients prior to MPI, and gene expression testing was then performed, with study investigators blinded to gene expression test results. Following MPI, patients were referred either to invasive angiography or to CT angiography (CTA), gold-standard measurements for diagnosis of coronary artery disease. A total of 431 patients were eligible for analysis, having completed gene expression testing, MPI and either invasive angiography or CTA.

In the COMPASS study, the gene expression test was superior to MPI in diagnostic accuracy, sensitivity (89 percent vs. 27 percent, p<0.001) and negative predictive value (96 percent vs. 88 percent, p<0.001) and demonstrated excellent performance for ruling out obstructive coronary artery disease relative to both invasive angiography and CTA.

Better methods for risk stratification of patients with obstructive coronary artery disease are needed. A study published in the March 11, 2010 issue of The New England Journal of Medicine found that in nearly 400,000 patients who underwent elective invasive angiographic procedures, 62 percent were found to have no obstructive coronary artery blockage.

The gene expression test used in the study, called Corus CAD (CardioDx, Palo Alto, Calif.), measures the RNA levels of 23 genes from a whole blood sample. Because these RNA levels are increased or decreased when obstructive coronary artery disease is present, the Corus CAD score indicates the likelihood that an individual patient does not have obstructive coronary artery disease.

"Chest pain symptoms account for two percent of all visits to the doctor's office each year," said Dr. Mark Monane, chief medical officer of CardioDx. "Corus CAD has now been validated in more than 1,100 patients in three separate studies. For physicians, methods to improve the diagnosis of symptoms suggestive of coronary artery disease represent a huge unmet need, and the Corus CAD test may help clinicians make better decisions. For patients, the test may lead to better diagnostic accuracy as well as avoidance of unnecessary procedures. For payers, we believe that Corus CAD can address a major expense category."

Explore further: Researchers find common test may be unnecessary for bariatric surgery candidates

Related Stories

Researchers find common test may be unnecessary for bariatric surgery candidates

July 19, 2011
A new study by researchers from Rhode Island Hospital has found that stress testing with myocardial perfusion imaging as part of a pre-operative workup for bariatric surgery candidates may be unnecessary. The research is ...

The next stage of heart function testing

October 11, 2011
A new non-invasive technique for measuring how well the heart and blood vessels function in patients already suffering from coronary artery disease could, in a single test, identify which abnormally narrowed blood vessels ...

New test for coronary artery disease linked to higher rates of cardiac procedures and greater costs

November 15, 2011
A new, noninvasive diagnostic test for coronary artery disease is associated with a higher rate of subsequent invasive cardiac procedures and higher health-care spending. That's according to an observational study of Medicare ...

Recommended for you

Could aggressive blood pressure treatments lead to kidney damage?

July 18, 2017
Aggressive combination treatments for high blood pressure that are intended to protect the kidneys may actually be damaging the organs, new research from the University of Virginia School of Medicine suggests.

Quantifying effectiveness of treatment for irregular heartbeat

July 17, 2017
In a small proof-of-concept study, researchers at Johns Hopkins report a complex mathematical method to measure electrical communications within the heart can successfully predict the effectiveness of catheter ablation, the ...

Concerns over side effects of statins stopping stroke survivors taking medication

July 17, 2017
Negative media coverage of the side effects associated with taking statins, and patients' own experiences of taking the drugs, are among the reasons cited by stroke survivors and their carers for stopping taking potentially ...

Study discovers anticoagulant drugs are being prescribed against safety advice

July 17, 2017
A study by researchers at the University of Birmingham has shown that GPs are prescribing anticoagulants to patients with an irregular heartbeat against official safety advice.

Protein may protect against heart attack

July 14, 2017
DDK3 could be used as a new therapy to stop the build-up of fatty material inside the arteries

Heart study finds faulty link between biomarkers and clinical outcomes

July 14, 2017
Surrogate endpoints (biomarkers), which are routinely used in clinical research to test new drugs, should not be trusted as the ultimate measure to approve new health interventions in cardiovascular medicine, according to ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.