Corus CAD test outperforms myocardial perfusion imaging in new study


CardioDx has announced that the COMPASS (Coronary Obstruction Detection by Molecular Personalized Gene Expression) study has been published in Circulation: Cardiovascular Genetics and indicates that the Corus CAD test outperforms myocardial perfusion imaging in overall diagnostic accuracy for obstructive coronary artery disease.

According to a CardioDx press release, the results of the prospective, multicentre study showed that Corus CAD, a blood-based gene expression test, demonstrated high accuracy with both a high negative predictive value (96%) and high sensitivity (89%) for assessing obstructive coronary artery disease in a population of patients referred for stress testing with myocardial perfusion imaging. 


The study’s authors conclude that using Corus CAD earlier in the diagnostic algorithm could reduce the number of invasive cardiac tests by more accurately evaluating the presence of obstructive coronary artery disease compared to the traditional algorithm of stress myocardial perfusion imaging in these patients.



COMPASS enrolled stable patients with symptoms suggestive of coronary artery disease who had been referred for myocardial perfusion imaging at 19 US sites.  A blood sample was obtained in all 431 patients prior to myocardial perfusion imaging and Corus CAD gene expression testing was performed with study investigators blinded to Corus CAD test results. Following myocardial perfusion imaging, patients underwent invasive coronary angiography or coronary CT angiography, gold-standard anatomical tests for the diagnosis of coronary artery disease.


The study was designed to provide additional independent validation of the Corus CAD test in a real-world intended use patient population of patients presenting for myocardial perfusion imaging, a common non-invasive test for CAD, and builds on the results of the previous PREDICT validation study.


The press release stated that Corus CAD requires only a simple blood draw for testing, making it safe, convenient, and easy to administer. The study evaluated results in stable non-diabetic patients with typical or atypical symptoms suggestive of CAD and found that Corus CAD surpassed the accuracy of myocardial perfusion imaging, a test that was administered more 10 million times in the US in 2010.


“The evaluation of stable patients with chest pain and other symptoms suggestive of coronary artery disease is a common challenge for clinicians, accounting for as many as 10,000 outpatient visits each day,” said the publication’s lead author, Gregory S  Thomas, medical director of the MemorialCare Heart & Vascular Institute at Long Beach Memorial Medical Center and clinical professor of Medicine and director of Nuclear Cardiology Education at the University of California-Irvine School of Medicine. “In the US, myocardial perfusion imaging testing is often performed in these patients and is followed by referral to invasive coronary angiography. Based on the results of this study of the Corus CAD gene expression test, we now have a reliable diagnostic approach for evaluating patients with symptoms of obstructive CAD.  With its high sensitivity and negative predictive value, Corus CAD may help clinicians accurately and efficiently exclude the diagnosis of obstructive CAD early in the diagnostic pathway, so they can assess for other causes of their patients’ symptoms.”