Reducing the Burden of Cardiovascular Disease with Precision Medicine

Precision medicine is an overarching term that describes the customization of healthcare, with medical decisions, practices, or products being tailored to each individual patient. In short, precision medicine means personalized medicine. It’s a new and emerging approach to treating patients based on their unique biology and genetic makeup and what is happening to them. This area of medicine has evolved since the mapping of the Human Genome fourteen years ago, and significant progress has been made since then.

Early on, personalized medicine seemed far-fetched. With information elucidated from the human genome, significant technology was developed to capture the molecular signatures of disease processes happening at the most basic levels. These discoveries enabled researchers to translate science into a new class of biomarker tests for clinical application that would tailor the diagnosis and treatment of disease specific to that patient. The first area of medicine to adopt these new tests was oncology. There is good reason for this, and it lies in the patient’s biology. Much of what happens with cancer is related to a person’s genes, including their inherited genetics. With oncology, we know that mutations in specific genes can affect a person’s cancer status and direct how they respond to medications and treatment. The relatively quick adoption of personalized genomic analysis in oncology, particularly as it relates to companion diagnostic tests used with specific oncologics, has not yet been seen in other disease areas. 

The state of personalized medicine in cardiology

Though slow to evolve, advances in the application of precision medicine tools in cardiology are taking place. These technologies have been slower to develop because diseases like coronary artery disease are multifactorial and are rarely limited to one or a small set of genes. Since a person’s environment, such as diet and lifestyle, contributes significantly to the manifestation of heart disease, researchers are studying the expression of the genome (e.g. gene expression, proteonomics, metabolomics), with the hopes of identifying biomarkers that would correlate with and predict cardiovascular disease. 

Recently, the American Heart Association (AHA) convened a team of experts to survey, review, and summarize their findings on advancements developed with the expressed genome and its impact on cardiovascular patient care. The resulting statement, The Expressed Genome in Cardiovascular Diseases and Stroke: Refinement, Diagnosis, and Prediction, was published in the journal Circulation: Cardiovascular Genetics. The authors of the AHA Scientific Statement shared their excitement and optimism with not only the current state of science, but also the advances it expects to realize from the expressed genome and its impact on personalized medicine in cardiology over the next few years.

The AHA defines the “expressed genome” in this way: “the inner workings of the body reflect the complex interplay of factors beyond the DNA sequence, including epigenetic modifications, RNA transcripts, proteins, and metabolites, which together can be considered the ‘expressed genome.’”

The AHA asserts “the emergence of high-throughput technologies, including epigenomics, transcriptomics, proteomics, and metabolomics, is now making it possible to address the contributions of the expressed genome to cardiovascular disorders.” The published AHA statement identifies two currently available commercial tests that underscore these advancements.

Article continues on page 2

Let’s look at one of the two clinically available tests born out of this research and science. The age, sex and gene expression score (ASGES), also known as the Corus CAD blood test, is used in the outpatient setting to help doctors rule out obstructive cardiovascular disorders in stable symptomatic patients with suspected coronary artery disease (CAD). It is known that 90% of stable chest pain patients seen in the primary care setting have symptoms attributed to non-cardiac sources such as gastrointestinal reflux disease (GERD), musculoskeletal pain, and anxiety, according to American Family Physician. The Corus CAD test provides the current likelihood of whether a patient has a significant blockage of coronary arteries on a real-time basis. Whereas one’s genes and genetic makeup can be used to extrapolate future risk, it is gene expression that can tell us about the here and now. By ruling out CAD early in the primary care setting, this frees the patient from worry and the doctor to pursue other non-cardiac causes. The early, appropriate use of this test for triage decreases the chance that the patient will be sent for a potentially unnecessary cardiac evaluation (cardiac imaging and cardiac catheterizations) that is costly and have associated with it procedural risks. The AHA cited the Corus CAD test as having the largest body of work around gene expression profiling for CAD, and that the test has been proven to be valid and useful.

How does a managed care organization evaluate whether to cover such tests?

Before recommending a test for coverage, we want to ensure it passes the litmus test.

1. What does the data look like? Has the test been proven valid in multiple populations that translate to real world experience?
2. If yes, then we want to ask whether there is clinical utility. Are physicians using the tests to change their management of the patient? Are patient outcomes improved with this product?
3. What is the pharmacoeconomic data? What is the cost/benefit of this new product?

The AHA’s statement supports that there is an adequate level of evidence for the ASGES test concerning its clinical validity and utility.

In the current healthcare climate, we know that cost is a constant source of discussion and stress. Cost savings, once we’ve checked the boxes of substantial and substantiated data and clinical utility, are an important consideration when deciding whether to add diagnostics and clinical advancements to treatment guidelines. I spent many years evaluating new products, including those in emerging fields and agree with the AHA that tests in the omics, genomics, genetics, etc., spaces are the future of advancement in cardiovascular medicine. It is encouraging that we are starting to see products like the ASGES test be supported by significant published data and mentioned in articles like the recent AHA Scientific Statement. Genomic tests can reduce the burden on clinicians and payers alike by providing personalized care to patients. I think that in light of that fact, payers and managed care entities should strongly consider the Corus CAD test as adequately proven and available for coverage.