Radiation Dose in Diagnostic Cardiac Catheterization: Results from the PROcedural RadiaTion Dose Exposure in Diagnostic Cardiac CatheterizaTION (PROTECTION VII) Study

Background: Cardiac catheterization is a frequently performed diagnostic procedure, but the associated exposure to ionizing radiation is a general healthcare concern. This study was designed to assess the level and development of radiation dose for diagnostic cardiac catheterizations (DCC).   Methods: In the PROcedural radiaTion dose Exposure in diagnostic Cardiac catheterizaTION (PROTECTION VII) study all DCC procedures reported to a nation-wide quality insurance program in Germany between 2008 and 2018 were included. The dose-area product (DAP) and radiation time were analyzed. Multivariate linear regression analysis was performed to identify predictors associated with radiation dose. Findings: We enrolled 5 401 525 patients undergoing DCC (median age 70 years, 40% female). The most frequent indication was the evaluation of suspected coronary artery disease in 43% of patients. The DAP of all DCC was 1 856 (IQR 990 - 3 290) cGy*cm2 and median radiation time was 3.0 (IQR 1.7 - 5.5) min. During the ten years of observation, median DAP significantly decreased by 47% (p < 0.001) resulting in 1 229 cGy*cm2 in 2018 (effective dose estimate 2.7 mSv). A 11.9-fold variability in median dose exposure was observed between catheterization laboratories in 2008, which was reduced to 4.5-fold in 2018 (both p < 0.001). Male gender, increased age, history of coronary-artery-bypass-graft surgery, heart failure and the respective indication were identified as independent predictors for increased radiation dose (all p < 0.001).   Interpretation: This large radiation dose survey demonstrates a considerable reduction in radiation exposure in DCC within the last decade. However, the inter-site variability underlines the need for further site-specific training and standardized implementation of low-dose protocols.  Funding: The PROTECTION VII study received no funding. Declaration of Interest: JH received speaker honoraria and research support from and serves as consultant for Abbott Vascular and Edwards Lifesciences. The other authors declare no conflict of interest. Ethical Approval: The PROTECTION VII study has been approved by the Federal Joint Committee (GBA), which is the highest decision-making body of the joint self-government of physicians in Germany (application number 2019-19/06).