Purpose
Echocardiographic surveillance for asymptomatic left ventricular systolic dysfunction (ALVSD) is advised in childhood cancer survivors (CCS), because of their risk of heart failure after anthracycline treatment. ALVSD can be assessed with different echocardiographic parameters. We systematically reviewed the prevalence and risk factors of late ALVSD, as defined by contemporary and more traditional echocardiographic parameters.
Methods
We searched databases from 2001 to 2020 for studies on ≥ 100 asymptomatic 5-year CCS treated with anthracyclines, with or without radiotherapy involving the heart region. Outcomes of interest were prevalence of ALVSD—measured with volumetric methods (ejection fraction; LVEF), myocardial strain, or linear methods (fractional shortening; FS)—and its risk factors from multivariable analyses.
Results
Eleven included studies represented 3840 CCS. All studies had methodological limitations. An LVEF < 50% was observed in three studies in 1–6% of CCS, and reduced global longitudinal strain (GLS) was reported in three studies in 9–30% of CCS, both after a median follow-up of 9 to 23 years. GLS was abnormal in 20–28% of subjects with normal LVEF. Abnormal FS was reported in six studies in 0.3–30% of CCS, defined with various cut-off values (< 25 to < 30%), at a median follow-up of 10 to 18 years. Across echocardiographic parameters, reported risk factors were cumulative anthracycline dose and radiotherapy involving the heart region, with no ‘safe’ dose for ALVSD.
Conclusions
GLS identifies higher prevalence of ALVSD in anthracycline-treated CCS, than LVEF.
Implications for Cancer Survivors
The diagnostic and prognostic value of GLS should be evaluated within large cohorts.
Protocol registration
PROSPERO CRD42019126588
In echocardiographic surveillance of anthracycline-treated childhood cancer survivors (CCS), left ventricular ejection fraction (LVEF) has insufficient prognostic value for future cardiac events, whereas longitudinal strain may be more sensitive. We describe the long-term incidence of cardiac events in CCS after previous measurement of LVEF and myocardial strain. Echocardiography, including four-chamber view longitudinal strain (4CH-LS), of 116 anthracycline-treated CCS was obtained between 2005–2009 (index echocardiography). Follow-up was obtained at the late-effects clinic. Primary outcome was occurrence of cardiac events, defined as either symptomatic heart failure, life-threatening arrhythmias, LVEF < 40% or cardiac death, in CCS with normal versus abnormal index 4CH-LS. LVEF from subsequent echocardiograms was obtained to evaluate its natural course as a secondary outcome. After index echocardiography (median 13.1 years since childhood cancer diagnosis), our study added a median follow-up of 11.3 years (median last clinical contact 23.6 years since diagnosis). Only three CCS developed a cardiac event (6.2, 6.4 and 6.7 years after index echocardiography), resulting in a ten-year cumulative incidence of 2.7% (95%CI 0.9–8.2). All three CCS had a clearly reduced index 4CH-LS and relevant cardiovascular risk factors, whereas their index LVEFs were around the lower limit of normal. Index LVEF correlated with index 4CH-LS but mean long-term natural course of LVEF was comparable for CCS with abnormal versus normal index 4CH-LS. Absolute 10-year cumulative incidence of cardiac events in anthracycline-treated CCS during long-term follow-up was low. Sensitive echocardiographic measurements, such as 4CH-LS may be useful to tailor surveillance frequency in a selected group of CCS without cardiovascular disease.
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