Radiation burden of contemporary diagnostic pathways for chronic coronary syndromes: an ancillary analysis of the international EURECA Imaging Registry

AIMS: To evaluate cumulative radiation exposure associated with contemporary diagnostic pathways in patients with suspected chronic coronary syndromes (CCS), and to assess the impact of first-line imaging strategies, downstream testing, geographic variability, and adoption of guideline-recommendations on radiation burden. METHODS AND RESULTS: This sub-analysis of the prospective, multicentre EURECA Imaging registry included 2058 patients (out of 2306 with available radiation data) undergoing at least one ionizing imaging test across 24 countries. Effective dose (ED) was calculated for each modality and cumulatively across diagnostic pathways. Median cumulative ED differed significantly according to initial testing strategy (p < 0.001). Single-photon emission computed tomography (SPECT)-first and computed tomography coronary angiography (CTCA)-first approaches were associated with a significantly lower radiation exposure (median ED 6.68 mSv, IQR 5.12-9.05 and 6.86 mSv, IQR 5.32-10.64, respectively), than an invasive coronary angiography (ICA)-first strategy (12.60 mSv, IQR 3.86-35.68). Marked inter-regional variability was observed across all modalities, with the highest doses generally reported in Eastern and Southern European countries. Guideline-adopting diagnostic pathways were associated with significantly lower cumulative ED in several regions. At multivariable analysis, hypertension, obesity, former smoking, and family history of coronary artery disease were independently associated with higher radiation exposure, while female sex, non-anginal symptoms, and guideline adoption predicted lower ED (all p < 0.01). CONCLUSIONS: Cumulative radiation exposure in CCS varies substantially according to diagnostic strategy and practice patterns. Non-invasive, guideline-adopting pathways are associated with lower radiation burden, whereas ICA-first approaches lead to higher exposure. Optimizing test selection and promoting guidelines adoption may improve radiation safety in cardiovascular imaging.