Radiation exposure of patients undergoing transcatheter aortic valve implantation and factors contributing to it

Background/ Introduction Aortic stenosis (AS) is a calcific disease which affects the aortic valve leaflets and is commonly prevalent in people who are 65 years and older. The global burden of AS is expected to keep on increasing due to the longer life expectancy as well as the morbidity and mortality associated with the disease. Transcatheter aortic valve implantation is utilised for the management of AS. Currently, TAVI is recommended as a first-line treatment for patients who are 75 years and older and those who are at an intermediate to high surgical risk, with the aim of becoming the first treatment option for patients who are 65 years and older. However, one of the concerns of TAVI is the need of ionising radiation during valve placement. The study of exposure to ionising radiation in the TAVI population is becoming progressively more important to consider due to the broader population being considered and the long-term effects related to radiation. Purpose Locally there was no data available covering this topic, thus the aim of the study was to quantify the radiation dose that patients receive during TAVI procedures and to determine any procedural and patient factors that contribute to this radiation dose. Methods Retrospective data analysis was performed for procedures effected between January 2019 and December 2022. All the patients that underwent a transfemoral (TF) TAVI and fit within the inclusion criteria were included in the study. The data was collected from medical databases and underwent a process of data cleaning before information relating to patient and procedural characteristics was extracted. Data about percutaneous coronary interventions (PCI) that were performed during the same time period by the same operators was collected for comparison purposes. Results In total the data of 241 TAVI patients was analysed. Dose Area Product (DAP) was the main radiation metric utilised to quantify the radiation dose. Non-parametric statistical tests were performed due to right-skewedness. The median (IQR) DAP for these procedures was 9000 cGym2 (5975-13150) and the median (IQR) fluoroscopy time was 18.25 minutes (15, 23.5). The years 2019 and 2020 had the lowest median DAP. The DAP obtained in this study is lower than the European DRLs of 13000 cGym2. The median (IQR) DAP (5320cGym2 (2385-9860)), and fluoroscopy time (13.75 mins (8.25-21.62)) for PCIs were lower than for TAVI and this difference is statistically significant (P = <0.001). DAP was not significantly related only to age category and the operator’s combination. Generalised linear models (GLM) showed that prosthetic valve size, body surface area (BSA) and aortic valve gradient are statistically significant predictors of DAP. Conclusion This study shows that the local TAVI patients receive a radiation dose which is within acceptable European limits and that valve size and patient’s BSA are the variables that impacted the radiation dose.