Angulation of the C-arm During Complex Endovascular Aortic Procedures Increases Radiation Exposure to the Head

Abstract

Introduction: Reliance on endovascular techniques and increasing procedural complexity means that the vascular interventionalist is exposed to significant radiation doses, particularly to unprotected body parts. We aimed to directly measure head and body radiation exposure to the operating team during complex endovascular aortic procedures. Methods: Between November 2013 and April 2014, consecutive elective branched and fenestrated endovascular aortic repairs (EVAR) performed in a hybrid operating theatre were prospectively analysed. Body (over-lead and under-lead) and head doses were measured for the primary (PO) and assistant operator (AO) using electronic dosimeters (Hitachi-Alokai). Fluoroscopy time, digital subtraction angiography (DSA) acquisition time, C-arm angulation and dose area product (DAP) were recorded. Data were analysed using Mann–Whitney U test and logistic regression modelling. Results: Twelve cases were analysed (Crawford II [n = 3], Crawford III [n = 2], Crawford IV [n = 7]), with a median operative time of 230min (IQR 180–308). Median age was 76 yr (71–80); median body mass index was 28.6 kg/m2 (25.4–32.0); 85% male. Stent grafts incorporated branches only (n = 4), fenestrations only (n = 6) or a mixture of branches and fenestrations (n = 3). A total of 17 branches and 24 fenestrations were cannulated and stented. Head dose was significantly higher in the PO compared with AO (53 μSv [19–106] versus 10 μSv [6–25], respectively; p = 0.014), as was over-lead body dose (87 μSv (43–114) versus 9 μSv (5–36), respectively; p = 0.003). The corresponding under-lead doses were similar between operators (p = 0.241). Left anterior oblique (r2 = 0.53; p = 0.009) and cranial (r2 = 0.63; p = 0.007) C-arm angulation, and time to cannulation of the superior mesenteric artery (r2 = 0.62; p = 0.01) were predictors of greater PO head dose exposure. Conclusion: The head is an unprotected area that receives a significant radiation dose during complex EVAR. The deleterious effects of exposure to this area are not fully understood. Operators should be cognisant of head exposure increasing with angulation of the C-arm and limit this manoeuvre.