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Corus CAD Clinical Validity

The clinical validation of the Corus CAD test was established in two prospective clinical studies: PREDICT and COMPASS. These studies documented the correlation between a Corus CAD score and the likelihood of finding obstructive coronary artery disease (CAD) in patients referred for either invasive coronary angiography (PREDICT) or myocardial perfusion imaging (COMPASS).

PREDICT
COMPASS

The PREDICT (Personalized Risk Evaluation and Diagnosis In the Coronary Tree) Study

Purpose:

To develop and validate the Corus CAD test.

Type:

Prospective

Size:

Over 4,000 samples collected from 39 sites in the U.S. The algorithm development and validation phases used 640 and 526 samples, respectively.

Study Design:

PREDICT1 enrolled patients who had been referred for invasive coronary angiography by their physician. Patients had a blood sample drawn just prior to their catheterization procedure. CardioDx received the angiography results from the catheterization procedure, including the clinician's assessment of the maximum percent stenosis, or level of CAD, in any of the major coronary arteries as well as clinical data. In addition to the local assessment of the extent of disease, each angiography used in the study was sent to a single third-party core lab for Quantitative Coronary Angiography, or QCA, to provide a second and independent assessment of the level of obstructive coronary artery disease*. A case was defined as any patient that had at least one lesion greater or equal to 50% stenosis by QCA, and a control was any patient with no lesions greater or equal to 50% stenosis. We compared the ability of the algorithm score to classify patients as to their case and control status from angiography and assessed whether the algorithm score had higher diagnostic performance than clinical factors alone.

Key Findings:

The PREDICT study demonstrated that the Corus CAD algorithm significantly classifies patients as to their obstructive CAD status and has a sensitivity of 85% and negative predictive value (NPV) of 83% at a score threshold of less than or equal to 14.75 in a population of men and women referred to the catheterization lab.

Status:

Published, Annals of Internal Medicine (October 2010)2

Identifier:

NCT00500617


* In the PREDICT Study, obstructive CAD is defined as at least one atherosclerotic plaque causing ≥50% luminal diameter stenosis in a major coronary artery (≥1.5 mm lumen diameter) as determined by invasive quantitative coronary angiography.

  1. PREDICT study. Clinical trial summary found at: www.clinicaltrials.gov, NCT00500617.
  2. Rosenberg S, Elashoff MR, Beineke P, et al. Multicenter Validation of the Diagnostic Accuracy of a Blood-Based Gene Expression Test for Assessing Obstructive Coronary Artery Disease in Nondiabetic Patients. Ann Intern Med. 2010;153:425-434.

The COMPASS (Coronary Obstruction Detection by Molecular Personalized Gene Expression) Study

Purpose:

To validate the Corus CAD test in an independent cohort of patients who had been referred for myocardial perfusion imaging (MPI), but who had not yet been referred for invasive coronary angiography. This population of patients more closely resembles the intended use population for the Corus CAD test than that observed in the PREDICT study.

Type:

Prospective

Size:

431 samples analyzed from 19 sites in the U.S.

Study Design:

COMPASS1 enrolled nondiabetic symptomatic patients who had been referred to MPI by their physician. If the MPI was positive and it was clinically indicated, the patient had an invasive coronary angiography. If the MPI was negative, the patient was referred to research coronary computed tomography angiography (CCTA) to assess what level of coronary disease, if any, was present. The investigators were blinded to the Corus CAD results. Investigators compared the ability of a Corus CAD score at a pre-defined threshold of 15 and MPI to accurately determine case-control status measured by invasive coronary angiography or CCTA.

Key Findings:

The COMPASS study found that the Corus CAD algorithm demonstrated a sensitivity of 89% and a negative predictive value (NPV) of 96% at the pre-specified threshold of 15 in a population of symptomatic men and women referred to MPI for the evaluation of obstructive CAD.

Status:

Published online, Circulation: Cardiovascular Genetics (April 2013)2

Identifier:

NCT01117506


  1. COMPASS Study. Clinical trial summary found at: www.clinicaltrials.gov, NCT01117506.
  2. Thomas GS, Voros S, McPherson JA, et al. A Blood-Based Gene Expression Test for Obstructive Coronary Artery Disease Tested in Symptomatic Nondiabetic Patients Referred for Myocardial Perfusion Imaging: The COMPASS Study. Circ Cardiovasc Genet. 2013;6(2):154-162.