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Subclinical diastolic dysfunction may be detected among adult survivors of childhood cancer before left ventricular ejection fraction (LVEF) becomes abnormally low, according to longitudinal echocardiographic data.

Among participants in the St. Jude Lifetime Cohort Study (SJLIFE) diagnosed with cancer at a median age of 8 years, the proportion of diastolic dysfunction was approximately 15% when assessed in their 30s, with cases usually appearing with concurrent systolic dysfunction, reported Cassady Palmer, BS, a cardiac sonographer of the Christ Hospital Health Network in Cincinnati, and colleagues.

Strictly isolated diastolic dysfunction, per traditional parameters, affected fewer than 5% of young adult survivors with preserved ejection fraction -- though global longitudinal strain (GLS) criteria suggested a prevalence of 9%, they noted in .

According to the study authors, left ventricular (LV) GLS improved the identification of diastolic dysfunction that appeared to have a generally low prevalence regardless of whether the cancer survivors had been given chest-directed radiation and/or anthracycline chemotherapy as children. These potentially cardiotoxic therapies are known to carry a dose-related increased risk of congestive heart failure and are associated with early mortality.

Yet definitions of cardiotoxicity continue to focus on LV systolic dysfunction alone.

Based on the present study, "tools capable of earlier detection of cardiotoxicity, including more precise assessment of diastolic injury, may improve the identification of patients with dysfunction who may benefit from intervention to preserve cardiac function," Palmer and team wrote.

"Despite the current definitions of CTRCD [cancer therapeutics-related cardiac dysfunction] focusing on systolic function, these results show that the incidence of [diastolic dysfunction] occurs in adult survivors of childhood cancer and provide evidence that supports diastolic assessment as part of the comprehensive evaluation of cancer treatment-related cardiac toxicity," noted Hector Villarraga, MD, and colleagues from the Mayo Clinic in Rochester, Minnesota.

In an , they explained that change in GLS precedes a decline in LVEF, adding that "identification of patients with diastolic dysfunction before a drop in ejection fraction but with abnormal GLS may play an important role in this patient population."

Palmer and colleagues said they relied on a relatively conservative GLS cutoff point of -15.9%, since there is no recommended threshold for this echocardiographic metric. Traditional parameters of diastolic dysfunction were based on the .

Importantly, it is unclear whether any observed diastolic dysfunction among cancer survivors was the result of cancer treatment or unrelated issues in adulthood such as hypertension, diabetes, and obesity, the authors cautioned.

This observational analysis included 3,342 adult cancer survivors (52.7% men) who underwent a baseline assessment at a median age of 30.1 years, with last follow-up at age 36.6 years.

Palmer and colleagues acknowledged that at SJLIFE's inception in 2007, echocardiography was risk-based and limited to patients exposed to anthracycline chemotherapy or chest-directed radiotherapy. In 2015, the cohort migrated to systematic echocardiographic follow-up regardless of exposure status.

Another limitation of the study was its lack of information on echocardiographic changes within 10 years from initial childhood cancer diagnosis.

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