Gender-specific blood RNA diagnostic test for obstructive coronary artery disease

22 August 2012

A new diagnostic test uses a blood sample to measure blood cell RNA levels of a number of genes to assess the presence of obstructive coronary artery disease.

 The test, the Corus CAD gene expression test developed by CardioDx Inc., gives a new tool for the assessment of non-diabetic patients, particularly women, with suspected obstructive coronary artery disease.

A study of the test has been published online in the American Heart Journal. The paper, titled. A Gender Specific Blood-Based Gene Expression Score for Assessing Obstructive Coronary Artery Disease in Non-Diabetic Patients: Results of the PREDICT Trial.

“Corus CAD is unique as it is the only gender-specific diagnostic test currently available that accurately risk stratifies patients with obstructive coronary artery disease, accounting for key biological differences between men and women,” said Alexandra Lansky, M.D., Associate Professor of Medicine and Director of the Cardiovascular Research Center at Yale University School of Medicine, who is the lead author of the study.

“This study found that commonly used diagnostic approaches, including symptom evaluation and myocardial perfusion imaging, performed less well in women than in men for identifying obstructive coronary artery disease. In contrast, the Corus CAD test performed well in both women and men. Corus CAD offers a reliable diagnostic approach for the assessment of non-diabetic patients, particularly women, with suspected obstructive coronary artery disease.”

The results of the analysis showed that Corus CAD test scores were significantly correlated with obstructive coronary artery disease in both male and female cohorts in PREDICT. The Corus CAD score was significantly and independently associated with obstructive CAD in both men and women, while symptoms of typical angina were significantly associated with obstructive CAD only for men (p<0.001).

 Women often have non-specific, atypical symptoms of CAD that make the assessment of CAD disease more difficult. Traditional diagnostic methods such as cardiac imaging do not account for gender-specific factors, and the real-world performance of these diagnostic tools is often compromised in women. In addition, many traditional tests involve radiation exposure, and cumulative effective doses of radiation from imaging procedures have been shown to be higher in women than in men.

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, despite the fact that the majority of patients (84 percent) had received noninvasive diagnostic tests prior to referral to catheterization.

The authors concluded that current modalities for identifying which patients should undergo elective invasive coronary angiography to diagnose obstructive CAD have limitations, and that better methods are needed for patient risk stratification. Typical and atypical presentations of stable chest pain account for up to two percent of all doctor’s office visits each year, or as many as 10,000 patients every day in the U.S.

“Traditional tests for obstructive coronary artery disease result in many cardiac catheterizations where no disease is found, especially in women,” said Mark Monane, M.D., Chief Medical Officer of CardioDx. “This analysis from the PREDICT trial adds to the clinical evidence demonstrating that the Corus CAD test can accurately and non-invasively help clinicians identify whether or not patients need further diagnostic cardiac evaluation, enabling many patients to avoid unnecessary testing and exposure to radiation risks or imaging agent intolerance.”

Further information

A Gender Specific Blood-Based Gene Expression Score for Assessing Obstructive Coronary Artery Disease in Non-Diabetic Patients: Results of the PREDICT Trial. American heart journal. Published online August 2012.

 

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