Patient radiation exposure during invasive graft surveillance after heart transplantation

Invasive procedures, including endomyocardial biopsy (EMB), right heart catheterisation (RHC) and coronary angiography (CA), are essential components of graft surveillance after heart transplantation (HTx). Fluoroscopy remains the primary imaging modality. Data on patient radiation exposure in HTx recipients are limited. The aim of this study was to investigate the kerma-area product (KAP, Gy.cm²), peak skin dose (PSD, Gy) and fluoroscopy time (s) in these procedures, assess trends in patient radiation exposure over time and identify the procedures contributing most to cumulative radiation during post-transplant surveillance.

Retrospective cohort study at a tertiary care centre including patients who underwent HTx between January 2018 and December 2019. All patients were followed through their invasive organ surveillance period with a median follow-up time of 4.9 years. For the primary end point, KAP (Gy.cm²), PSD (Gy) and fluoroscopy time (s) were assessed. Secondary end points were procedural success rate and procedure-related complications.

A total of 382 procedures were performed: 330 EMB (86.4%), 22 EMB+RHC (5.8%), 30 EMB+CA with or without RHC (7.8%). The mean annual KAP from fluoroscopic procedures per patient was 50.9±3.95 Gy.cm² in the first post-transplant year, dropping to 11.1±6.1 Gy.cm² by year 5 (p<0.001). By day 387 after HTx, 50% of the total dose was reached. CA was the primary contributor to radiation peaks beyond year 1. Radiation per EMB procedure decreased significantly over time (p=0.002). Procedural success rate was 98.2%, with a 1.0% complication rate.

Radiation exposure is highest in the first-year post-HTx, with CA contributing most to later peaks. Time-specific and procedure-specific strategies are warranted to minimise exposure and optimise long-term care.