• July 2019

    Keeping cardiovascular genetic testing top of mind

As with most medical progress, the rapid advancement in treatment modalities for various forms of cardiovascular disease has been made possible in part by a better understanding of disease pathology.

Genetic testing is playing an increasingly important role in diagnosing and developing a care plan for certain cardiomyopathies, aortic disease, arrhythmias, atherosclerotic risk factors and other forms of cardiovascular disease.

The presence of a hereditary component is often overlooked across many forms of cardiovascular diseases, according to Robert Gottlieb, MD, PhD, a heart failure specialist on the Baylor Scott & White Heart and Vascular Hospital – Dallas medical staff.

“For aortic diseases, providers often stop the conversation at Marfan syndrome, and they forget to think about the rest of it,” says Dr. Gottlieb, who has a clinical focus in cardiovascular genetics.

“Providers will refer a Marfan patient along for genetic testing, and they’ll refer a basketball player along for genetic testing just because of tall stature, but they might not know there is a reason to refer along a patient with unexpected aortic rupture or aortic aneurysm, regardless of how tall or lanky. It can be a challenge to remember the aorta because it cannot be seen or measured during a clinical exam.”

Beyond aortic disease, there are other groups for whom genetic testing may be useful. Many patients labeled as being affected by a viral cardiomyopathy actually have a familial cardiomyopathy. Those patients may not become symptomatic until an illness or stressor, leading to an incorrect conclusion that it is viral. The same is true for certain arrhythmias, which may in fact be caused by a genetic condition predisposing patients to extra circuits in cardiac tissue.

The ability to uncover any genetic component and beginning to take preventative measures as appropriate can be crucial to preserving function and reducing risk of sudden cardiac death (SCD).

Finding a Cause

“We have to look beyond the label of someone dying from a massive heart attack and ask ‘what really happened?’” says Dr. Gottlieb. Many patients who experience SCD have an underlying familial disease. Determining precise disease pathology can have important ramifications for surviving family members.

According to a review published in JAMA Cardiology in October 2017, “Obtaining a detailed family history is critical to identify families who will benefit from genetic testing, determine the best strategy, and interpret results.”

The review recommends a family approach to genetic testing at multidisciplinary centers with clinicians who have a high level of expertise and experience in genetic testing.

Dr. Gottlieb agrees, “It requires a lot of expertise to do genetic testing.”

He points out there are not only medical risks in interpreting complex genetic results, but there could be legal and insurance considerations as well. “Sometimes a negative test is re-assuring, but sometimes it just means we as a field just don’t know why they have what they have. We need to ensure that each test is interpreted correctly, and that requires knowing who is being tested, why they are being tested, and who in the family is affected.”

Purpose and Considerations

Ideally, testing begins with the patient known to be affected by a potential hereditary cardiovascular condition, while he or she is still alive. If a familial component is discovered, first-degree relatives should next be considered for testing.

  • Genetic testing can improve care by serving as a basis for an individualized treatment plan based on disease mechanism and phenotypic subgroups.
  • Testing should be limited to the clinical question at hand, as there is a risk of over-testing and finding results that may not be meaningful, but cause undue worry for the patient.
  • The timing of testing is typically in adolescence or early adulthood, but may vary.
  • There are employment and medical insurance protections against genetic discrimination.
  • The cost of genetic testing has gone down considerably over the past decade.

Many patients who are aware of a familial cardiovascular condition often live under the assumption that they will eventually be impacted by the condition as well. Genetic testing and counseling can help empower these patients by confirming their suspicion or alleviating their fear.

If confirmatory, a program to surveil the condition, initiate preventive steps and make recommendations on medications and activities to avoid can be made. Almost as important, is being able to remove the disease burden from a patient with no need to carry it.

“It is a gift you can give a patient when they assume they are going to get a condition and you can tell them that they are not,” says Dr. Gottlieb.