The burden of radiation exposure in congenital heart disease: the Italian cohort profile and bioresource collection in HARMONIC project

Abstract Background The European-funded Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy in Pediatrics (HARMONIC) project aims to improve knowledge on the effects of medical exposure to ionizing radiation (IR) received during childhood. One of its objectives is to build a consolidated European cohort of pediatric patients who have undergone cardiac catheterization (Cath) procedures, with the goal of enhancing the assessment of long-term radiation-associated cancer risk. The purpose of our study is to provide a detailed description of the Italian cohort contributing to the HARMONIC project, including an analysis of cumulative IR exposure, reduction trend over the years and an overview of the prospective collection of biological samples for research in this vulnerable population. Methods In a single-center retrospective cohort study, a total of 584 patients (323 males) with a median age of 6 (2–13) years, referred at the Pediatric Cardiology in Niguarda Hospital from January 2015 to October 2023, were included. Biological specimens from a subset of 60 patients were prospectively collected for biobanking at baseline, immediately post-procedure and after 12 months. Results Two hundred fifty-nine (44%) patients were under 1 year old at their first procedure. The median KAP/weight was 0.09 Gy·cm2/kg (IQR: 0.03–0.20), and the median fluoroscopy time was 8.10 min (IQR: 4.00–16.25). KAP/weight ratio showed a positive correlation with the fluoroscopy time (Spearman’s rho = 0.679, p