For years physicians have assessed coronary artery disease (CAD) by reviewing a patient's symptoms, medical history and cardiovascular risk factors, as well as use tests that yield anatomical and functional information about the heart and its vessels.

While there have been tremendous advances surrounding the technologies that treat this disease, the diagnostics tools used to identify CAD hasn't quite kept the same pace.

A new test from CardioDX (Palo Alto, California) promises to give physicians far greater insight on a patient's probability of having obstructive CAD. The company reported launching its Corus CAD test in select states, and that the test recently completed the PREDICT multicenter validation study.

Corus CAD at its core is a genomic test that was developed after physicians expressed dissatisfaction with some of the shortcomings of imaging tests like stress echocardiography, myocardial perfusion imaging and computed tomography angiography.

"We usually take a tremendous amount of time with physicians before we delve into the R&D phase of our products," David Levison CEO and founder of the 5-year-old CardioDX told Medical Device Daily. "We asked physicians what were the challenges in the diagnosis and care of coronary patients."

The number one response the company received was that clinicians and doctors were trying to get a more objective look into identifying and predicting the occurrence of serious cardio disease, according to Levison.

The company, once finding out what direction it should go in, started work on proving a hypothesis that there is a strong correlation between the peripheral blood gene expression and CAD.

"Physicians said give us a test that has a very high sensitivity level so they can rule out any patients who might not be at risk," he said. "Our test is much more objective in nature [than imaging tests on the market]. The result is going to be the same every time you run a sample, and not necessarily depend on how a clinician views an image."

To date the company has collected more than 2,800 patient samples through PREDICT from more than 40 clinical sites in the U.S. Trial results and the Corus CAD validation data are expected to be presented toward the end of 2009.

Here's how the test works:

The clinician takes a simple blood sample, without exposing the patient to radiation, contrasts or dyes and it is then sent to CardioDx's CLIA-certified laboratory for gene expression analysis. CardioDx scientists use quantitative real-time polymerase chain reaction (qRT-PCR), a highly sensitive laboratory process for precise quantification of gene expression. Validated in a rigorous multi-center trial, Corus CAD integrates the expression levels of 23 genes and other patient characteristics empirically shown to indicate obstructive CAD.

Results are delivered to the physician via a patient report that includes a numeric score between 0 and 40.

"The higher the score the more likely obstructive coronary disease could occur in the patient," Levison told MDD.

He added that the test combines gene expression information with standard information from clinical assessments and enables physicians to have a "more complete picture" of their patient's disease, and allows for more "individualized" and "informed" patient care decisions.

As of now the test is only available in nine states Kentucky, Maryland, Illinois, Washington, Wisconsin, Minnesota, North Carolina, Texas and Arizona. Plans call for tests to be administered in more states next year.

"With this test, for the first time physicians have the biology behind the imaging," Levison said. "We've developed a test that is very actionable. It's a test that can give physicians a [road map] to determine the next course of action for patients."

CardioDx is a cardiovascular genomic diagnostics company providing physicians with clinically validated tests to enable more informed and individualized patient care decisions. The company is strategically focused on developing products for three forms of cardiovascular disease: CAD, cardiac arrhythmias and heart failure.

Omar Ford, 404-262-5546;