An algorithm is a mathematical formula or equation derived from extensive biostatistical analysis, that, when applied to measurements of specific genomic markers (e.g., gene expression), provides a score that can assess likelihood of a current or future disease state.
Angina is chest pain or chest discomfort when a person’s heart muscle does not get enough blood, because of blockages in the coronary arteries. Some patients may feel this as pressure in the chest, squeezing pain in the chest, or pain in the shoulders, arms, neck, jaw, or back.
In a case-control clinical trial, a case is defined as a patient with disease. In the PREDICT trial, a case is defined as a patient having 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 (QCA). (See Control.)
CLIA (Clinical Laboratory Improvement Amendments)
Congress passed the Clinical Laboratory Improvement Amendments (CLIA) in 1988, establishing quality standards for all laboratory testing to ensure the accuracy, reliability, and timeliness of patient test results regardless of where the test is performed. All CardioDx tests are processed in a CLIA-licensed laboratory.
Clinical Study or Trial
Clinical studies are research studies designed to answer specific questions regarding safety or efficacy of emerging tests or therapeutics or new applications of known tests or therapeutics.
In a case-control clinical trial, a control is defined as a patient without disease. In the PREDICT Trial, a control is defined as a patient having no atherosclerotic plaque(s) causing ≥50% luminal diameter stenosis in a major coronary artery (≥1.5 mm lumen diameter) as determined by invasive quantitative coronary angiography (QCA). (See Case.)
Coronary angiography is an invasive procedure using X-ray imaging technology and a contrast agent to visualize the lumen, or interior, of the blood vessels of the heart. This examination is performed in the cardiac catheterization lab.
Coronary Artery Disease (CAD)
CAD is a disease caused by atherosclerotic luminal narrowing of the coronary arteries leading to the heart, which limits the supply of blood to the heart. (See Atherosclerosis.)
Corus CAD is the only blood test that can quickly and safely identify symptomatic patients unlikely to have obstructive* coronary artery disease (CAD).
A gene is an ordered sequence of nucleotides that is located in a particular position on a particular chromosome. Genes contain information to make specific proteins, which then express specific traits or carry out functions in living things.
Gene expression is the process by which genetic information from DNA is made into a functional gene product through transcription into mRNA and translation into protein. RNA levels change as a result of disease processes happening inside a person’s body and can be used to inform on current disease status. The Corus CAD gene expression test provides information about a person’s current disease state because it measures the activity of specific RNAs known to be involved in the response to and development and progression of atherosclerosis.
Genetics is the scientific study of inheritance, as it relates to heritable traits, diseases, and other characteristics. Genetic testing uses various approaches to identify genetic variations, traits, mutations and predispositions. The results of genetic testing are constant throughout an individual's lifetime and can help estimate a person’s risk of developing disease in the future.
Genome-Wide Association Study (GWAS)
A genome-wide association study is the empirical clinical study approach that examines the entire genome with the goal of identifying single nucleotide polymorphisms (SNPs) uniquely present in patients with disease (cases) relative to those without disease (controls).
Heart failure is a structural problem or functional impairment that limits the ability of the heart to pump effectively and provide adequate blood flow to the body and organs, resulting in fluid build-up, difficulty breathing, and lung congestion.
Human Genome Project
The Human Genome Project is an international scientific project (1990–2003) that successfully culminated in the sequencing of the first entire human genome and the identification of its approximately 25,000 genes.
Quantitative Coronary Angiography (QCA)
Considered the "gold standard" for evaluating obstructive CAD, QCA is an objective, semi-automated method for calculating maximal percent stenosis as found during invasive coronary angiography. QCA was used as the endpoint in the PREDICT trial where the Corus CAD gene expression score was correlated to the maximal percent diameter stenosis as determined by QCA.
Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR)
qRT-PCR is a technology used to quantify DNA sequences. This technique is useful in determining the presence and amount of a single, specific sequence within a sample of DNA.
Single Nucleotide Polymorphism (SNP)
A SNP (pronounced "snip") is a variation of a single nucleotide in the human genome. (See Polymorphism.)
Stenosis is a narrowing within any tubular structure. In cardiovascular disease, this is specifically related to the narrowing of an artery or, less often, a vein. Arterial stenosis due to atherosclerotic disease can result in the obstruction of blood flow, or cardiac ischemia.
Sudden Cardiac Arrest (SCA)
Sudden cardiac arrest is the sudden, abrupt loss of heart function typically caused by rapid, irregular ventricle rhythms, either ventricular fibrillation (VF) or ventricular tachycardia (VT). The quivering ventricles are unable to pump blood to the body, and the condition is lethal 95% of the time if not treated in time (i.e., sudden cardiac death).
Sudden Cardiac Death (SCD)
Sudden cardiac death is death as a result of an unattended sudden cardiac arrest (SCA) event. (See sudden cardiac arrest.)
* 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 (QCA).