CardioDx Releases More Studies Validating Use of Its Assay

CardioDx, the California-based molecular laboratory, has issued two new studies connecting its blood-based assay to the reduction of further cardiac interventions.

The most recent study, which was published in Circulation: Cardiovascular Quality and Outcomes, concluded that the use of the company's Corus CAD test to determine the risk of cardiac obstructive disease led to far fewer referrals for often pricey—and inconclusive—cardiovascular diagnostics and procedures.

The study focused on 718 medically stable and non-acute adults without a history of obstructive coronary artery disease from 21 primary care practices who underwent the Corus CAD assay from September 2012 to August 2014. Those who scored on the lower end of the risk spectrum were 82 percent less likely to be referred for additional testing, according to the data.

"Data from recent studies suggest that physicians have a challenging time accurately risk stratifying patients presenting with stable symptoms suggestive of obstructive CAD," said Joseph A. Ladapo, M.D., an assistant professor of medicine at the New York University School of Medicine and lead author of the study, in a statement. "Our analysis ... demonstrates that using the score that incorporates age, sex, and gene expression in a primary care setting in patients with symptoms suggestive of obstructive CAD can help clinicians safely and efficiently rule-out low-risk patients."

Oftentimes, patients are referred for cardiac stress tests and other workups for symptoms such as unspecific chest pains or tightness. The practice was highlighted in a recent article in the New Yorker magazine by physician Atul Gawande, who noted that procedures such as cardiac ultrasounds, the placements of cardiac stents and even heart bypass procedures are commonplace in patients whose medical history and complaint show little need for such interventions, which can cost tens of thousands of dollars and place the patient in other perils. This even happened to Gawande's mother, who received a carotid ultrasound and cardiac catheterization after fainting. It turned out that Gawande's mother had fainted due to dehydration and lack of food.

The second CardioDx study focused specifically on women patients and was published online by Menopause: The Journal of The North American Menopause Society. The study focused on 320 women who were medically stable but had symptoms suggesting they might have obstructive coronary artery disease. Of those women, 77.5 percent had Corus CAD test results suggesting they had a low risk for the disease. Only 4 percent of those women were referred for additional diagnostics and treatments.

CardioDx officials indicated the test can prove especially useful in women, who are often more difficult to diagnose as having obstructive coronary artery disease than men and therefore are often subject to more testing and other procedures that may be medically unnecessary.

Commercial health insurers Aetna and Coventry Health began covering the assay last year for any non-diabetic adult enrollees without a history of coronary artery disease who are experiencing chest pain or equivalent symptoms. CardioDx also raised $35 million in financing late last year from the Alberta Investment Management Corporation.

Takeaway: CardioDx is providing more clarity as to when interventions are required in patients with some symptoms suggestive of a cardiac issue.