Key result
X-ray exposure (median 5.6-6.4 mSv) during pediatric cardiac catheterization increased gamma-H2AX foci, yielding an estimated lifetime cancer mortality risk of 4% vs 1% with standard models.
Why the study?
Does cardiac catheterization induce DNA double-strand breaks (measured by gamma-H2AX foci) in pediatric patients with congenital heart disease?
Observational (n=49)
Does cardiac catheterization induce DNA double-strand breaks (measured by gamma-H2AX foci) in pediatric patients with congenital heart disease?
gamma-H2AX foci indicate that radiation risk estimates from pediatric cardiac catheterization using the linear-no-threshold hypothesis may underestimate the true risk of DNA damage and subsequent cancer mortality.
Suggests pediatric catheterization radiation may confer higher cancer mortality risk than standard models; challenges linear-no-threshold assumptions and leaves validation open.
BACKGROUND: A better knowledge of patient x-ray dose and the associated radiation risk in pediatric interventional cardiology is warranted in view of the extensive use of x-rays and the higher radiosensitivity of children. In the present study, gamma-H2AX foci were used as a biomarker for radiation-induced effects. Patient-specific dose was assessed and radiation risks were estimated according to the linear-no-threshold model, commonly used in radiation protection, and the gamma-H2AX foci data. METHODS AND RESULTS: In 49 pediatric patients (median age, 0.75 years) with congenital heart disease who underwent cardiac catheterization procedures, blood samples were taken before and shortly after the procedure. gamma-H2AX foci were determined in peripheral blood T lymphocytes. In each patient, a net increase in gamma-H2AX foci, representing DNA double-strand breaks induced by interventional x-rays, was observed. In addition, a patient-specific Monte Carlo simulation of the procedure was performed, resulting in individual blood, organ, and tissue doses. Plotting of gamma-H2AX foci versus blood dose indicated a low-dose hypersensitivity. Median effective doses calculated according to the International Commission on Radiological Protection 60 and 103 publications are 5.6 and 6.4 mSv, respectively. The lifetime-attributable risk of cancer mortality was calculated from the linear-no-threshold model and the gamma-H2AX foci data. This resulted in lifetime-attributable risk values of 1% and 4%, respectively, for the patient population under study. CONCLUSIONS: gamma-H2AX foci as a biomarker for DNA damage indicate that radiation risk estimates according to the linear-no-threshold hypothesis are possibly underestimates. Great care should be taken to minimize and optimize patient radiation exposure.
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Beels et al. (2009) conducted an observational in Congenital heart disease (n=49). X-ray exposure during cardiac catheterization vs. Baseline (before procedure) was evaluated on Net increase in gamma-H2AX foci and lifetime-attributable risk of cancer mortality. X-ray exposure (median 5.6-6.4 mSv) during pediatric cardiac catheterization increased gamma-H2AX foci, yielding an estimated lifetime cancer mortality risk of 4% vs 1% with standard models.
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