Is It Time to Update Guidelines For Family HCM Screening?

A new study suggests that early screening guidelines for phenotype-positive hypertrophic cardiomyopathy (HCM) may be missing a significant number of children.

Published in the European Heart Journal, the analysis included children who underwent family screening for HCM prior to 18 years of age. The authors defined major cardiac events (MaCEs) as sudden cardiac death, or the need for cardiac interventions (myectomy, implantable cardioverter defibrillator insertion, or transplantation). The patients sample included 524 screened children, 331 of whom were under the age of 10. Of those, 9.9% had echocardiographic evidence of HCM, and 1.1% were symptomatic at screening time.

According to the study results, the median onset time of HCM in the patient population was 8.9 years. A total of 91.0% of the children were free of phenotype-positive HCM at 10 years of age, and of 80 phenotype-positive children, 42 (52.5%) became phenotype-positive before age 10. A total of 17 children experienced MaCEs during follow-up, seven of whom experienced it before age 10. The median age for MaCE was 10.9 years. The researchers noted that 13 of 17 children with a MaCE had early onset HCM.

They also determined that 201 (38.4%) of the children fulfilled criteria for early screening based on symptoms or a family history of sudden cardiac death. Among the 42 children who experienced HCM before age 10, however, only 29 met the criteria for early screening. They also reported that upon multivariable Cox regression analysis, the male gender, a family history of sudden cardiac death, P/LP variant in MYH7 or MYBC3 in child or family were associated with early onset HCM.

“The results of our study coupled with other recent evidence of the yield on clinical screening in young family members indicate that disease prevalence and penetrance as well as event rates are not lower in children compared to adolescents (and adults),” the researchers wrote in their paper. “Although annual event rate in children who develop HCM is low, given the potential for rapid progression, early detection of clinical HCM is important in order to facilitate close follow-up and timely interventions to prevent sudden cardiac death, and to alleviate symptoms of worsening left ventricular outflow obstruction before adverse events occur.”

They concluded: “Younger family members should be considered for early clinical and genetic screening to identify the subset in need of close monitoring and interventions.”

Time to change family screening for hypertrophic cardiomyopathy?
-524 children screened, 331 were under 10 years of age
-9.9% had echo evidence of HCM, and 1.1% were symptomatic at first screening.
– Median age at HCM onset was 8.9 y, and MACE 10.9 y.https://t.co/V7vAMB1lW7 pic.twitter.com/Ne1NSX6y2R

— Juan Pablo Costabel MD 🇦🇷 (@jpcostabel) June 24, 2019

The study findings highlight the need for starting screening of family members at a young age to permit early diagnosis. #HCBiobank #HCM #CMP #familyscreening https://t.co/gLbMnzLbVg

— Heart Centre Biobank (@hcbiobank) July 17, 2019