National Diagnostic Reference Levels for Endovascular Aneurysm Repair in Sweden

The 2023 European Society for Vascular Surgery (ESVS) guidelines on radiation safety recommended establishment of national diagnostic reference levels (DRLs) for endovascular procedures, which indicate an expected radiation dose for any given procedure for the average sized patient. The aim of this study was to propose a national DRL for Sweden for standard endovascular aortic repair (EVAR).

This was a national registry based study where all EVARs performed in Sweden over a two year period (2021 - 2022) were identified in the Swedish vascular registry, Swedvasc. Patient demographics were extracted from Swedvasc and radiation related parameters were collected at centre level. Multivariable analyses were performed to assess which factors affected fluoroscopy time, total dose area product (DAP), and cumulative air kerma (CAK). The national DRL was defined as the third quartile of all centre specific median values for DAP total.

Nine hundred and thirty-three procedures at 23 centres were included; 831 (89.1%) intact abdominal aortic aneurysms (AAAs) and 102 (10.9%) ruptured AAAs. The median (interquartile range [IQR]) DAP for EVAR at centre level varied from 28.3 Gy·cm² (IQR 14.1, 76.1) to 212.7 Gy·cm² (IQR 196.8, 275.0). Overall, the third quartile of the DAP radiation dose for EVAR in Sweden was 152.6 Gy·cm². The DAP was a median 81.1  Gy·cm² and 116.5 Gy·cm² for intact and ruptured EVARs, respectively (p < .001). The DRL was 147.7 Gy·cm² and 213.8 Gy·cm² for intact and ruptured EVARs, respectively. In a multivariable linear regression analysis, rupture, iliac branched repair, access complication, obesity, low centre volume and larger aneurysm were predictors for higher DAP during EVAR.

The current report proposes a DRL for DAP of 152.6 Gy·cm² for EVAR procedures in Sweden, with specific benchmark DAP values proposed for subgroups of patients. There is a considerable difference in radiation dose between different centres, suggesting a potential for implementation of improved radiation routines in some centres based on benchmarking.