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Support for dilated-cardiomyopathy screening in affected families

Reuters Health - 01/02/2022 - A new analysis shows that family members of patients with idiopathic dilated cardiomyopathy (DCM) have a "substantial" lifetime risk of developing the condition, supporting a role for family-based DCM screening, researchers say.

"For the first time, this study gives us hard numbers on how to counsel family members on their risk of developing DCM, and especially so for family members of Black patients with DCM," Dr. Ray Hershberger of The Ohio State University Wexner Medical Center, in Columbus, told Reuters Health by email.

"The lifetime risk of DCM is at least one in five for family members of patients with DCM, and is higher in Black families. So the guidelines, that with a diagnosis of DCM, family members need to undergo clinical screening, should be followed," Dr. Hershberger said.

DCM is the chief cause of clinical heart failure, a leading indication for heart transplant. DCM has long been observed to run in families, suggesting the presence of shared genetic and non-genetic factors.

Early identification in at-risk family members could provide the opportunity to initiate treatment early. Yet, accurate, up-to-date estimates of the prevalence of familial DCM are lacking.

To that end, Dr. Hershberger and colleagues did a cross-sectional study of 1,220 patients with DCM, defined as left ventricular systolic dysfunction and left ventricular enlargement after excluding usual clinical causes, and 1,693 of their first-degree relatives.

The prevalence of familial DCM was estimated at 29.7% in first-degree relatives and the estimated cumulative risk of DCM by age 80 years in family members was 19%, they report in JAMA.

These estimates were higher (56.9% and 33%, respectively) when using an expanded definition of familial DCM that included first-degree relatives who had partial phenotypes in addition to first-degree relatives who had DCM.

The risk of familial DCM was higher in Black than in white first-degree relatives but did not differ significantly between Hispanic and non-Hispanic relatives. The cumulative risk of familial DCM was greater in relatives of patients diagnosed with DCM at younger ages.

"These findings are relevant to the care of the families of patients diagnosed as having DCM and provide an estimate for clinicians practicing at a U.S. advanced heart failure program of the cumulative risks of DCM or partial phenotypes in first-degree relatives of their patients," the study team writes.

"While DCM is usually silent until late-phase disease, often presenting with heart failure, conventional medical treatment has been shown to mitigate asymptomatic DCM," they point out.

Therefore, the findings support cardiomyopathy guidelines that call for counseling patients diagnosed with DCM regarding risk to family members and screening first-degree relatives for DCM, they say.

The author of an accompanying JAMA editorial notes that "existing trial data support a role for evidence-based neurohormonal agents (such as angiotensin-converting enzyme inhibitors) to prevent the progression of asymptomatic left ventricular systolic dysfunction to overt and symptomatic clinical heart failure."

The current study "suggests the utility of family-based clinical screening for DCM to more readily identify the individuals with preclinical disease who might benefit from the early initiation of neurohormonal therapies," writes Dr. Krishna Aragam of Massachusetts General Hospital in Boston.

He says more study is needed to better define the best timing and frequency of familial DCM screening as well as the role of genetic testing in routine practice.

Nonetheless, Dr. Aragam says this study provides a "critical first step to comprehensively understand the risks associated with familial DCM and the value of family-based clinical screening. Forthcoming efforts are poised to build on the important findings from this study to change the narrative for DCM from one of 'diagnose and treat' to that of 'preempt and prevent.'"

Support for this research was provided by the National Institutes of Health.

SOURCE: https://bit.ly/3rrYA5z and https://bit.ly/3KZDfIi JAMA, online February 1, 2022.

By Megan Brooks

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