project: cardiodx

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Glossary

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Algorithm

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

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.

Arrhythmia

Arrhythmia is any disorder of the heart rate or heart rhythm, in which the heart beats too quickly (tachycardia), too slowly (bradycardia), or with an irregular pattern (fibrillation).

Atherosclerosis

Atherosclerosis is the accumulation of lipoproteins, cellular products, calcium, and other substances, all referred to as plaque, in the inner lining of an artery.

Bioinformatics

Bioinformatics is the analysis of biological data using advanced computational and statistical techniques.

Cardiac Catheterization

Cardiac catheterization is an invasive procedure used to examine the heart in coronary angiography and diagnose the presence and extent of coronary artery disease (CAD).

Case

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.

Control

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

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

Corus CAD is the only blood test that can help healthcare providers quickly and safely assess whether or not their patients' chest discomfort or other symptoms may be due to obstructive coronary artery disease (CAD). The Corus CAD test is a decision-making tool that can help identify patients unlikely to have obstructive CAD and help clinicians determine appropriate next steps for patient management.

DNA (Deoxyribonucleic Acid)

DNA is a nucleic acid that contains the hereditary genetic material for all living things. DNA is present in all human cells.

False-Negative

A negative result that occurs when the condition is present. An example of a false-negative would be if a particular test designed to detect pregnancy returns a negative result but the person is indeed pregnant.

False-Positive

A positive result occurs when the condition is not present. An example of a false-positive would be if a particular test designed to detect pregnancy returns a positive result but the person is not actually pregnant.

Gene

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

Gene expression is the term used to describe gene activity, or production of RNA (ribonucleic acid), in response to environmental factors. Gene expression occurs throughout a person's life in most cells and tissues. Gene expression can change in response to disease and other conditions. Some tests incorporate gene expression to help healthcare providers assess a patient's disease status. Gene expression tells you what's happening in your body right now.

Gene Expression Profile

A gene expression profile is the specific gene expression pattern from a set of genes within an individual.

Genetics

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

A genome is the complete hereditary information for a particular organism that is encoded in DNA.

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).

Genomics

Genomics is the study of the entire genetic makeup of an individual (their genome) coupled with the interaction of those genes with each other and with the individual’s environment.

Heart Failure

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.

Ischemia

Ischemia is a restriction of blood flow, and therefore oxygen, to any area of the body. Cardiac ischemia specifically relates to the restriction of blood to the heart.

Messenger RNA (mRNA)

Messenger RNA is a type of RNA transcribed from DNA and involved in protein synthesis.

Metabolomics

Metabolomics is the systematic study of small molecule metabolites found in bodily fluids such as whole blood.

Microarray

A microarray is a high-throughput technology that enables the detection of gene expression levels or the detection of single nucleotide polymorphisms (SNPs) within the genome.

Myocardial Infarction (MI)

Myocardial infarction, commonly referred as heart attack, is an irreversible damage of cells in the myocardium due to restricted blood flow.

Myocardial Perfusion Imaging (MPI)

Myocardial perfusion imaging is an imaging procedure that illustrates the function of the heart, through the injection of radioisotope dye.

Nucleotide

Nucleotides are the basic unit for DNA and RNA, consisting of a nitrogenous base, a phosphate group, and a sugar.

Polymorphism

Polymorphism is the presence of more than one allele (or genetic variation) in a given population.

Proteins

Proteins are large, complex molecules made up of amino acids. They are essential to biological function.

Proteomics

Proteomics is the study of the complete complement of the function and structure of proteins within an organism.

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 test 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.

RNA (Ribonucleic Acid)

RNA is a kind of nucleic acid that contains phosphate, uracil, and ribose. RNA is responsible for regulating gene expression and the synthesis of proteins.

Single Nucleotide Polymorphism (SNP)

A SNP (pronounced "snip") is a variation of a single nucleotide in the human genome. (See Polymorphism.)

Stenosis

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.)

Transcriptome

The complete set of transcripts present in a given cell.